Title of Invention

"CLUSTER KEY ARRANGEMENT"

Abstract A cluster key arrangment may be mechanically configured or eletronically configured, The cluster kay arrangment may include twelve cluster keys configured in an arrangement of three columns by four rows, such as conventionally found on standard telephones. The cluster key arrangement may also be eonfigured for user on cellular/mobile telephones, television remote controls, other handheld, data entry devices, automotive controls. desktop/will-mounted/coedless telephones, combination telephone recorders, Personal Digttal Assistants, and other electronic devices. The mechanically or electronically configured cluster keys provide a user with the abiliiy to select one of a plurality of key elements representing numbers, letters, symbols, function, etc. in a manually exclusives manner.
Full Text CLUSTER KEY ARRANGEMENT TECHNICAL FIELD
The present invention relates to a cluster key arrangement which provides a user with the ability to select one of a plurality of key elements representing numbers, letters, symbols, functions, etc., in a mutually exclusive manner.
BACKGROUND ART
The touch-tone dial system has become the standard dialing system for conventional telephones, largely replacing the older rotary dial. The standard touch-tone dials have push-buttons arranged in a rectangular matrix pattern. Each button activates a switch to energize a tone generator of unique frequency. In addition, the push-buttons are arranged to activate a common switch for disconnecting the transmitter while a tone generator is operating.
Use of a telephone keypad with a telephone keypad matrix as a data terminal for the input of alphanumeric characters into a computer system, using or via a telephone line which further in turn forwards the message from the terminal to a service provider computer, such as a paging system, facsimile device, e-mail and/or voice mail system, or Personal Digital Assistants (PDAs) which have the ability to store schedules, memos, etc., and further have the ability to upload and download information from a base computer, which are operated on an on-board 'battery with an operating life of many days for a monochrome display, and an operating life of on the order of six hours for displays with color capability which are increasingly desirable for clarity and user friendliness, and cellular phones with desirable code

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division multiple access (CDMA) technology which provides for better voice quality and security having only about two to three hours of CDMA talk time are some of the trends in this area.
The most obvious form of elementary clustering is noticed in the standard 102 or 104 key personal computer keyboards in the grouping of the directional arrows. Other than copying this idea on some cellular telephone models, this has not resulted in any clustering of other keys either in patents or in commercially available products. Thus, what is being proposed here is not a mere extension of the preceding, which would be obvious to those skilled in the art. Rather, what is being proposed here derives from an identification of the deficiencies of the prior art and an invention that; overcomes those deficiencies.
It is worthwhile to review contradictions between standards that have come about due to their divergent origins but nonetheless find themselves in a convergent path due to emergence of technology driven changes. The most obvious example is the "789" arrangement of the calculator industry and the "123" arrangement of the pushbutton telephone. The horizontal "1234567890" derived from the "QWERTY" typewriter keyboard forms the backbone of computer data entry with the "789" calculator still present on the right hand side as a rarely used vestigial organ. Most of the numerical entries are done on the QWERTY side. Other non-QWERTY approaches, although better in concept have not really taken off. The preceding is mentioned also to reinforce that certain consumer "corporate memory" driven preferences will prevail as in QWERTY and in other cases the "123" of the telephone has clearly become more dominant instead of the "789" of the calculator. However, the same "123"'s additional alphabet assignments, upon "force

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fitting" them for additional uses such as for paging and e-mails have not been user friendly.
Most cell phones serve the purpose of audio(voice) interaction and are often used in unsafe but widely-prevalent "while driving in an automobile mode". Typically numbers are punched in or a received call is answered by pressing a button most often with the thumb. Thus, user friendliness based on ergonomic features is a must. Thus, making the individual number buttons as large as possible is a must. In reality all products in the market have seen a trend toward miniaturization of the keycap size, driven by factors such as: (1) relentless downsizing in width (Ericsson KH668 is 1 3/4" for example contrasted with Nokia 2190 at 2 1/4" and Casio's CP-850 cordless telephone is 2 1/4") . Product sleekness can still be achieved by better utilization of the space available; (2) "Real Estate" requirements for the liquid crystal display and the control keys have made the keypad size shrink further in the top vertical direction, typically being 1 1/2" for the primary keys (1, 2, 3, 4, 5, 6, 7, 8, 9, 0, *, and #). In most cell phones, the control keys comprising ON/OFF and NO/END are in one button (in Ericsson KH6S8) , the SEND or YES (to answer
an incoming call) is a second button, a CLEAR button

along with two forward and backward arrows make up five keys. An additional switch may be located on the side surface. Conceptually, the prior art deficiency stems from on the one hand mindless and unimaginative miniaturization of the human interface in attempting to keep up with electronic miniaturization and assuming wrongly that all the control keys need to be associated with the display and consequently are better positioned at the top in one separate row which happens to take up the most space. In actuality, the two largest keys (ON/OFF and NO/END) and (SEND/YES) have more functional association with the primary

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function of the telephone without a display. The minimal set of keys for the display are three, i.e. CLEAR, and two arrow keys.
The related art is represented by the following patents of interest.
U.S. Design Patent Number 397,694, issued on September 1, 1998 to Nicholas Mischenko et al. , shows an ornamental design for a faceplate having a keypad cover for a portable telephone. Mischenko et al. do not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 4,370,528, issued on January 25, 1983 to Louis F. Aschenbach, describes a miniature sealed toggle switch. Aschenbach does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 4,418,247, issued on November 29,
1983 to Kaj B. Hansen, describes an electrodynamic
transducer which has an additionally improved
sensitivity and can be produced almost completely
automatically. Hansen does not suggest a cluster key
arrangement according to the claimed invention.
U.S. Patent Number 4,439,647, issued on March 27,
1984 to Nick Calandrellb, describes a capacitive
keyboard which uses a standard printed circuit board
provided in various locations with spaced conductor
pairs. Calandrello does not sugaest a cluster key
arrangement according to the claimed invention.
U.S. Patent Number 4,680,577, issued on July 14, 1987 to David H. Straayer et al, , describes a multipurpose keyswitch for controlling cursor movement on a CRT display and for character entry. Straayer et al. do not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 4,687,200, issued on August 18, 1987 to Ichiro Shirai, describes a multi-directional switch in which on-off operation of multiple contacts

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is dependent on the pressing directions of the switch. Shirai does not suggest: a cluster key arrangement according to the claimed invention.
U.S. Patent Number 4,891,777, issued on January 2, 1990 to James M. Lapeyre, describes a keyboard for use by one hand and adapted for entry of a large number of selections including those for alphanumeric data processing and a large range of computer operation commands. Lapeyre does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 4,918,264, issued on April 17,
1990 to Masato Yamamoto et al. , describes a switching
device capable of returning to the neutral position of
the operating member or centering itself by the
resilience of a rubber switch. Yamamoto et al. do not
suggest a cluster key arrangement according to the
claimed invention.
U.S. Patent Number 5,057,657, issued on October 15,
1991 to Vedran Skulic, describes a low profile
keyboard switch, having tactile and/or audible
attributes for use in combination with a digitally
operable, membrane switch array. Skulic does not
suggest a cluster key arrangement according to the
claimed invention.
U.S. Patent Number 5,22,7,594, issued on July 13, 1993 to Louis G. Russo, describes an electrical switch assembly. Russo does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,253, 940, issued on October 19, 1993 to Max Abecassis, describes a method to arrive at a single standard for numeric keypad layouts that provides consumers the means to setfor themselves a single numeric keypad standard, and in this manner lead to the abandonment of layouts inconsistent with the layout incorporated on telephone devices. Abecassis does not suggest a cluster key arrangement' according to the claimed invention.

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U.S. Patent Number 5,339,358, issued on August 16,
1994 to Adel Danish et al. , describes a data terminal
enabling a user to easily input alphabetical, as well
as numerical characters, into a telephone for input to
a computer which in turn accesses a service provider
computer, Danish et al. do not suggest a cluster key
arrangement according to the claimed invention.
U.S. Patent Number 5,378,862, issued on January 3,
1995 to Hideo Tasaka et al. , describes a switch which
provides different switching inputs by pushing
different operating portions of a single operating
button. Tasaka et al. do not suggest a cluster key
arrangement according to the claimed invention.
U.S. Patent Number 5,386,091, issued on January 31, 1995 to Kevin F. Clancy, describes a low profile keyswitch for use with a computer keyboard, calculator and other electronic machines that process data and information. Clancy does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,3 96,030, issued on March 7, 1995 to Hiroshi Matsumiya et al., describes a control-key mechanism. Matsumiya et al. do not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,430,262, issued on July 4, 1995 to Hiroshi Matsui et al. , describes a combination push switch device comprising a single push button with at least two push members which can independently operate at least two switch elements. Matsui et.al. do not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,612,690, issued on March 18, 1997 to David Levy, describes a compact keypad system in which each function may be actuated comfortably by an adult-sized human finger. The key pad electronics are designed to register simultaneously actuated keycaps at an interstice as an input uniquely

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associated with the symbol located at the interstice. This distinguishes over the present invention because in the present invention a single character is generated in a mutually exclusive manner depending upon which specific key of a cluster key is depressed. Levy does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,631,453, issued on May 20, 1997 to Takuya Maeda, describes a multi-way flipping switch in which a movable contact can be reliably brought into contact with a stationary contact to thereby attain a stable contact state, and is capable of preventing two or more pairs of switching elements from being simultaneously turned on while securing the requisite waterproofness for the contact section. Maeda does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,666,113, issued on September 9, 1997 to James D. Logan, describes a system which automatically switches use of a touch sensitive computer input touchpad between the functions of cursor control and keypad emulation. Logan does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5, 758, 295, issued on May 26, 1998 to Bjorn Ahlberg et al., describes a single mode mobile cellular telephone with a man-machine interface which is the same for all cellular telephone systems. Ahlberg et al. do not suggest a cluster key

arrangement according to the claimed invention.
U.S. Patent Number 5,818,437, issued on October 6, 1998 to Dale L. Grover et al. , describes a highly efficient reduced keyboard which is used in conjunction with a display. The keyboard has twelve keys, nine of them labeled with numerous letters and other symbols, and those nine plus one more are labeled with one of the ten digits. Textural entry

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keystrokes are ambiguous. The user strikes a delimiting "select" key at the end of each word, delimiting a keystroke sequence which could match any of many words with the same number of letters. The keystroke sequence is processed with a complete dictionary, and words which match the sequence of keystrokes are presented to the user in order of decreasing frequency of use. The user selects the desired word. The letters are assigned to the keys in a non-sequential order which reduces chances of ambiguities. The present invention generates a single character in a mutually exclusive manner depending upon which specific key of a cluster key is depressed. Grover et al. do not suggest a cluster key arrangement according to the claimed invention.
U.S, Patent Number 5,841,374, issued on November 24, 1998 to Joseph N. Abraham, describes a compact, pocket computer for word processing utilizing keys which combine a plurality of toggle switches or multidirectional keys in a pocket size case. Abraham does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,844,506, issued on December 1, 1998 to Ronald P. Binstead, describes a touchpad comprising an electrically insulating membrane with a first series of spaced apart conductors on a first face of the membrane and a second series of spaced apart conductors on or proximal thereto, in which there is no electrical contact between the first and second series of conductors. Binstead does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,852,414, issued on December 22, 1998 to Seymour H. Yu et al. , describes a triangle-shaped 4-way-switching key for a keypad consisting of 10 keys alternating upwards and downwards pointing positioned for entering alphanumeric data into a

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computer or communication device. Yu et al. does not suggest a cluster key arrangement according to the claimed invention.
U.S. Patent Number 5,861,823, issued on January 19,
1999 to Gary J. Strauch et al. , describes a data entry
device having multifunction keys, which can produce
more than one character depending upon how the key is
depressed. Separation of the intended function of
depressing the central primary key is achieved in all
three embodiments through a second function key which
puts the device in a primary function or a
multifunction mode. Strauch et al. requires the
generation of at least two characters, a primary
character and at least one secondary character, upon
depression of any key. This distinguishes over the
present invention because in the present invention a
single character is generated in a mutually exclusive
manner depending upon which specific key of a cluster
key is depressed. Strauch et al. does not suggest a
cluster key arrangement according to the claimed
invention.
Germany Patent document 3,234,417 Al, published on March, 22, 1984, describes a keyboard for generating an alphanumerical symbol. Germany ' 417 does not suggest a cluster key arrangement according to the claimed invention.
Germany Patent document 3,532,201 Al, published on March, 19,, 1987, describes an electronic keyboard. Germany '201 does not suggest a cluster key arrangement according to the claimed invention.
Great Britain Patent document 1,035,193, published on July, 6, 1966, describes an electric switch which includes fixed contacts and a moving bridging contact in the form of a surface of revolution carried by a support on which it is free to turn about its axis and with which it can be moved generally in a radial direction at right angles to the line joining the

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fixed contacts to engage them. Great Britain '193 does not suggest a cluster key arrangement according to the claimed invention.
Great Britain Patent document 1,313,754, published on April 18, 1973, describes a joystick controlled switch apparatus comprising an operating lever rotatable about a pivot point in a support intermediate first and second portions of the lever. Great Britain '754 does not suggest a cluster key arrangement according to the claimed invention.
Japan Patent document 1-93249, published on April 12, 1989, describes a character information input device. Japan '249 does not suggest a cluster key arrangement according to the claimed invention.
An article entitled "THE ABCS OF KEYPAD LOGIC", by Mike Mills, published February, 15, 1999 in the Washington Post, describes a keypad operating in conjunction with software to disambiguate keystrokes entered by a user to make a highly educated guess of what the user is trying to spell. The keyboard has twelve keys, nine of them labeled with numerous letters and other symbols, and those nine plus one more are labeled with one of the ten digits. Textural entry keystrokes are ambiguous. The user strikes a delimiting "select" key
at the end of each word, delimiting a keystroke
sequence which could match any of many words with the
same number of letters. The keystroke sequence is
processed with a complete dictionary, and words which match the sequence of keystrokes are' presented to the user in order of decreasing frequency of use. The use selects the desired word. The letters are assigned to the keys in a non-sequential order which reduces chances of ambiguities. The present invention generates a single character in a mutually exclusive manner depending upon which specific key of a cluster key is depressed. This article does not suggest a

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cluster key arrangement according to the claimed invention.
An article entitled "INVENTOR ON THE VERGE OF A NERVOUS BREAKTHROUGH", by David Stipp, published March 29, 1999 in Fortune Magazine, pages 106-116, describes a palm-sized keyboard with full-sized keys. This article does not suggest a cluster key arrangement according to the claimed invention.
An article entitled "SEMI-CAPTIVE KEYBOARD", published in February, 1976 in Xerox Disclosure Journal Vol. 1 Number 2, page 85, describes a keyboard for information encoding with minimal finger movement by the operator. This article does not suggest a cluster key arrangement according to the claimed invention.
An article entitled "COMPACT COMPUTER KEYBOARD" published in March, 1985 in IBM Technical Disclosure Bulletin, Vol. 27 No. 10A, pages 5640-5642, describes a small computer keyboard that retains the conventional spatial relationships among the alphabetic keys without reducing the standard surface area for finger contact on each key or the spacing between adjacent keys. This article does not suggest a cluster key arrangement according to the claimed invention.
An article entitled "SMART. KEY", published in October, 1985 in IBM Technical Disclosure Bulletin Vol. 28 No. 5, pages 1859-1860, describes a special key positioned on the keyboard portion of an interactive terminal for controlling cursor positioning at the terminal display by touch control. This article does not suggest a cluster key arrangement according to the claimed invention.
An article entitled "SPACE BAR THAT ROLLS", published in August, 1989 in IBM Technical Disclosure Bulletin Vol. 32 No. 3B, pages 700-701, describes a space bar-which can rotate along its long axis in order to* provide an additional function. This article does not

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suggest a cluster key arrangement . according to the claimed invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.
DISCLOSURE OF INVENTION
The present invention is a cluster key arrangement.
The cluster key arrangement may be mechanically
configured or electronically configured. The cluster
key arrangement may include twelve cluster keys
configured in an arrangement of three columns by four
rows, such as conventionally found on standard
telephones. The cluster key arrangement may also be
configured for use on cellular/mobile telephones,
television remote controls, other handheld data entry
devices, automotive controls,
desktop/wall-mounted/cordless telephones, combination telephone recorders, Personal Digital Assistants (PDAs), and other electronic devices. The cluster keys provide a user with the ability to select one of a plurality of key elements representing numbers, letters, symbols, functions, etc., in a mutually exclusive manner.
The mechanical cluster keys each include a primary key and at least one secondary key. The number of secondary keys is. preferably in the range of four to eight. The mechanical cluster keys are preferably constructed from material giving • a large range of hardness that may be needed to provide positive tactile feedback to the user. The primary key preferably includes a dome or convex shaped button profile further shaped circularly, ellipsoidally, pentagonally, etc., as viewed from the top. The dome or convex shaped primary key profile as it reaches the vicinity of the secondary key assumes a concave

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profile. While a concave profile may be substituted for a dome, other button shapes, as viewed from the top, such as hexagonal, heptagonal, or octagonal maybe substituted. The secondary keys preferably each have a concave profile starting at the perimeter of the primary key somewhat underneath the primary key in elevation and rise up in a concave arcuate profile to increase the contact surface area of the fingertip for better pressure distribution and ends with a greater width such as obtained by the wide end of a trapezoid, for providing a greater width to the finger to act on, and ends at an elevation which is slightly lower than the top elevation of the dome of the primary key, with which it is clustered. Other secondary key profiles, as viewed from the top, may include shapes such as rectangular, trapezoidal, semi-circular, or elongated to provide more finger contact.
The primary keys are each labelled with a number, an
asterisk symbol (*) , or a pound sign (#) . The
secondary keys are each labelled with a function
designation, letters, or character symbols. Each key
has a first portion of the key exposed on a first side
of the key cluster, and a second portion and third
portion of the key exposed on a second side of the key
cluster. When the first portion of a key is depressed
by a user, the second portion of the primary key comes
into contact with the second portions of the secondary
keys with which, it is clustered and mechanically
mutually excludes any of the corresponding secondary
keys' third portions of that particular key cluster
from contacting a substrate such as a prxnted circuit
board or an intermediate layer of an elastomeric sheet
that has hat like protrusions with attached conductive
elements under the hats to complete a circuit upon
being depressed. If the primary key is depressed,
none of the associated secondary keys may contact the
substrate. If a secondary key is depressed preferably

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neither the associated primary key nor the remaining secondary keys may contact the substrate. It is possible that if a secondary key is depressed, at least two of the immediately adjacent secondary keys will be precluded from acting on the substrate.
One technique for detecting a depressed condition of a key utilizes a capacitive key wherein a key circuit element forms two spaced apart metallic areas and has a plated pad formed from a metal such as tin, nickel, or copper such that when the key end is brought in close proximity to the current element, a capacitive charge is noted by a keypad circuit board and a key-depressed state is acknowledged by a corresponding keyboard microprocessor and logic unit. An alternative construction incorporates a hardcontact keyboard, wherein the key has a stem which directly engages with the concave cavity, in close proximity with a pair of contacts comprising the circuit element which are then brought into electrically communicative relationship therebetween. Such a configuration for use in association would include physical shell caps on a flexible board spaced from a circuit board which includes metallic contacts. The shell caps each include a metallic element within the cap. When a user presses one button of a selected cluster key, a signal is generated when the key bottom of the key presses a shell cap and causes the associated metallic element to contact a metallic contact.
A mechanical cluster key arrangement configured for use on-a remote telephone, includes a housing, a speaker, and a microphone. The" housing also includes a liquid crystal display. Openings in the housing are provided for the individual cluster keys. In addition, the remote telephone may also include a buzzer; indicator lights, and other features, depending upon a particular design or model. The remote telephone includes a main printed circuit board

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which includes all of the major radio frequency (RF) and logic circuits required to provide at least basic cellular telephone service and support a variety of features. Such circuits typically include a plurality of chips, integrated circuits, and other components interconnected formed within, or on the surface, of . the printed circuit board. The remote telephone also includes an antenna that extends through an aperture provided in the housing and is electrically connected to the printed circuit board.
The housing encloses a substrate on which are mounted the closing switches and the dial pulse circuit which is controlled by these switches. Upon reception of RF signals, the mobile telephone receives the RF signals through the antenna. The antenna converts the received RF signals into electrical RF signals for use by the radio circuitry. The radio circuitry demodulates the electrical RF signals and recovers the data transmitted using the RF signals. Additionally, the radio circuitry outputs the data to a processor. The processor includes at least a main processor and associated memory as well as other control circuits including integrated circuits or other known technologies. The processor formats the data output from the radio circuitry into a recognizable voice or message information for use by the user interface. The user interface communicates the received information or voice to a user through the use of the speaker and the display. All digital or all analog or combinations of analog and digital network based cellular telephone services are possible.
Unlike present analog systems and other digital systems that divide the available spectrum into narrow channels and assign one or more conversations to each channel, CDMA is a wideband spread spectrum technology that spreads multiple conversations across a wide

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segment of the broadcast spectrum. Each telephone or. data call is assigned a unique code that distinguishes it from the multitude of calls simultaneously transmitted over the same broadcast spectrum. So long as the receiving device has the right code, it can pick its conversation out from all the others.
Another mechanical cluster key arrangement according to the invention includes cluster keys which each include a primary key circularly surrounded by a concave shaped secondary key. The various possible shapes attributed to the primary and secondary keys in the previously described mechanical cluster key arrangements are also possible in this mechanical cluster key arrangement. The cluster keys in this cluster key arrangement are preferably constructed from material giving a large range of hardness that may be needed to provide positive tactile feedback to the user. As before, typically, the primary keys are each labelled with a number, an asterisk symbol {*), or a pound sign (#) . The secondary keys are each labelled with at least one function designation, letter, or character symbol. Each key has a first portion of the key exposed on a first side of the cluster key assembly, and a second and third portion of the key exposed on a second side of the cluster key assembly. When the first portion of a key is depressed by a user, the third portion of the key comes into contact* with a substrate while its second portion mechanically mutually excludes any functions associated with the corresponding secondary key of that particular cluster key from contacting the
substrate.
The primary key travels through a stepped hole in the key cluster. When the primary key is actuated, a shoulder on the primary key mates with steps in - the secondary keys. This engagement of the shoulder of the primary key with the steps in secondary keys traps

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the secondary keys against the substrate and prevents them from rotating and rolling over the surface of the substrate. Since the secondary keys are actuated by rotating and rolling over the substrate, the secondary keys can not be actuated when the primary key is actuated.
When a secondary key is actuated by rotating and rolling over the surface of the substrate, it positions the primary key at an angle with the substrate. If the primary key is then depressed, this angle will cause the edge of the primary key to contact the substrate and prevent the bottom face of the primary key from making contact. Since actuation of the primary key is produced by the bottom face contacting the substrate, this prevents actuation of the primary key when a secondary key is actuated. Each secondary key includes a bottom surface which includes electrical traces corresponding to the number of functions designated on the upper surface of the secondary key. Selection of one function mutually precludes the selection of the other secondary key functions or the primary key function.
An electronic cluster key arrangement comprises a
primary key and at least one secondary key and is
electronically configured in the form of a transparent
a touch screen liquid crystal display (LCD) mounted
within a remote telephone which includes a housing, a
speaker, and a microphone. Obviously, this
electronically configured touch screen LCD cluster key
arrangement may also be configured for use on
cellular/mobile telephones, television remote
controls, other handheld data entry devices,
automotive controls, desktop/wall-mounted/cordless
telephones, combination telephone recorders, PDAs, and
other electronic devices, according to the desires of
the user. The cluster keys in this electronic «
configuration are preferably displayed in the form of

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circular, ellipsoidal, pentagonal, etc., images as viewed from the top. The secondary keys each preferably displayed in the form of rectangular, trapezoidal, semi-circular, images which may be elongated to provide more finger contact.
The housing also includes a liquid crystal display Many approaches to the determination of the location of X and Y coordinates of a touch point based on sensing pressure are well known. A pressure-sensitive input device comprising an X-coordinate detection resistive element connected to mutually parallel vertical conductors and a Y-coordinate detection* resistive element connected to mutually parallel horizontal conductors, for detecting the position of a point depressed by a stylus or the like, works by detecting changes in the resistance values of these resistive elements. Switches are used for on-off control of the current flowing1 into or out of both ends of the X-coordinate detection "resistive element and the Y-coordinate detection resistive element, and a voltage detection circuit detects the voltage between the X-coordinate detection resistive element and the Y-coordinate detection resistive element. Multiple inputs can be detected based on the results from the voltage detection circuit when the currents v are switched by the switches.

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The preceding is but one approach to pressure sensing based location determination known in the art. A more sensitive "smart sensor" type micro-strain gage based localized point sensor located at the midpoint of the keycaps of the primary keys and at the midpoint of the secondary keycaps, located along the circumference of a circle which constitutes the ^virtual circle" along which lie the locus of the centers of the secondary keys of the various embodiments, This sensitive pressure sensor can output an analog pressure level and its digitized digital equivalent and likewise the rate of change of pressure and its digitized equivalent. The sensor is a smart sensor in that it can be embedded in the carrier material.
The first level of mutual exclusivity is rather trivial. The system logic will not accept inputs from two different cluster keys; such dual activation attempt will occur when a user inadvertently presses two adjacent secondary keys belonging to two different clusters (the system will output an error message and sound a beep asking the user to move the finger a little closer to the center of the cluster) . It can also occur when one purposely tests the system by pressing keys from clusters that are not adjacent (this will merely elicit a beep and optionally display an error message).
Once the finger is operating within a cluster, the finger perhaps overlaps a little over let us say 3 keys.,.. The intended secondary key {let us say the alphabet B) , the corner of the primary key (which is the number 2) and a portion of the adjacent secondary key (say the letter A}... under these circumstances, the pressure sensor that is distributed over the entire "keycap" areas of both the secondary keys and the primary key will generate a logical YES for these keys. However, the more sensitive pressure sensor

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located in the-middle {lower threshold) will in most instances have an output only in the intended secondary key of B. This output in reality has two components, an analog level (or its digitized equivalent) representing the amount of or relative amount of pressure (this is likely to be the highest in the intended secondary key since presumably the finger tip is acting on it. For further reliability, a rate input will also be generated in identical fashion. When uniqueness is established the logical outputs from the other two keys are precluded from proceeding further. h simple implementation would accomplish this inside the box with conventional electronics. It is also possible to implement this in a solid state or monolithic way by opening the conductive pathway from the non intended keys thus making it mutually exclusive.
A second pressure sensor, i.e., the generalized or entire keycap based pressure sensor also needs to be there for another case, i.e.1 when one attempts to provide a very clean input by using a pen tip or stylus as is done on palmtop PDAs these days. This capability falls under the realm of user friendliness, since there are many users who use this method currently, albeit with a complaint. Of course they are doing it because they have no choice.
The touch screen LCD could be of the monochromatic type or an active matrix full color display. As is known widely to those skilled in the art, an active matrix generally consists of two sheets between which is inserted an electro-optical material such as a liquid crystal. On one of the sheets is a matrix of transparent conductive blocks, thin film transistors, a group of conducting addressing lines, and a group of conductive addressing columns. Each transistor has-a gate connected to a line, a source connected to a block, and a drain connected to a column. On the

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second sheet is a counter electrode. In one electronic cluster key arrangement, on top of the liquid crystal material is attached a flexible transparent film which has patterned thin film semiconductor layers preferably comprising a layer of i (intrinsic) -type semiconductor disposed between a layer of p-type semiconductor and a layer of n-type semiconductor. The p-i-n layer is further sandwiched on either side by a thin layer of transparent conductive layer such as tin oxide, indium tin oxide, or the like, to constitute a p-i-n junction amorphous silicon solar cell.
A silicon solar cell connected to the emitter of a common base amplifier biased so that the cell voltage is near to zero, a short-circuit load can be used as a sensor. Collector load is three forward diodes which develop an approximately logarithmic voltage versus current in the current ranges involved. The next stage provides the alternating current (AC) coupling for the pulses, so that the sensitivity of the sensing system is essentially independent of the light level on the cell. This stage is an operational amplifier with a bypass on the feedback for high AC gain and low direct current (DC) gain. This network also has a low-pass net to reject noise spikes picked up from the environment. The coverage of the conductive layers by an actuating finger causes shadowing which results in a decreased current output proportional to the area shadowed.
The p-i-n junction amorphous silicon solar cell is scribed, preferably using a laser scriber, into smaller portions comprising one primary portion and at least one peripheral secondary portion {preferably four secondary portions around the primary portion) to configure an electronic cluster key. The p-i-n junction amorphous silicon solar cell include at least one vertical and horizontal grid of transparent

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conductors laid in between two transparent insulating
layers of the thin film variety such as silicon
dioxide. The p-i-n junction amorphous silicon solar
cell's two conductive transparent coatings of tin
oxide, indium tin oxide, or the like, can be combined
in series using techniques well known to persons
skilled in the art to provide a trickle charge at
approximately 12-14 volts. One approach to series
connection entails using a laser to scribe and
separate the initial tin oxide coating into islands,
using a photoresist mask on the edge to prevent the
subsequent layers of p-type, i-type, and n-type
semiconductors from touching the conductive layer.
Thereafter, the mask is removed and the second tin
oxide layer is applied which connects the top surface
of the second cell to the bottom surface of the first
cell, resulting in a series connection. Other
intervening steps are well known to those versed in
the art. The p-i-n junction amorphous silicon solar
cell may include capacitors and/or pressure sensors at
the center of each key which are all deposited on a
flexible transparent substrate such as Kapton and then
glued on to the LCD. Kapton or other high temperature
plastic is used to withstand high temperatures
associated with chemical vapor deposition of amorphous
silicon. It is possible to integrate the processing
of the solar cell and the touch screen LCD based on
active matrix thin film transistors (TFTs) .
The touch screen LCD is preferably an active matrix TFT display which.preferably displays the primary keys as white key .with black characters for most contrast and which preferably displays secondary key alphabet characters in a particular color such as red. Preferably secondary key function symbols are displayed in green, secondary key characters such as the AT sign (@) are displayed in blue, and secondary key control symbols such as YES/SEND are displayed in

23
yellow with green letters and NO/END are displayed in yellow with red letters. Obviously, a variety of other color assignments are possible.
The electronic cluster key arrangement is configured utilizing a keyboard emulator within the remote telephone in accordance with the mode selected by the user using the mode switch. One arrangement showing an electronic cluster key arrangement comprises a set of twelve cluster keys arranged in four rows by three columns. Each electronically configured cluster key includes a primary key location surrounded by at least one secondary key location. By touching a particular key location on the touch screen LCD, the user activates an electrical signal which passes through an electrical matrix formed by a plurality of contact lines interconnecting each of the particular key locations. The electrical signal is delivered to a processing unit stored within the remote telephone, which is then converted into a symbol and displayed on the LCD. The remote telephone also includes circuitry which precludes the simultaneous activation of more than one key location of a particular cluster key.
The electronic or opto-electronic mutually exclusive cluster key arrangement works on the same basis of preprocessing as was done in the mechanical cluster key arrangements wherein only one signal could be generated at a time. In the electronic cluster key arrangement the preprocessing is based on sensing one or more variables such as contact pressure or shadowing of a solar cell's microcell element. Both analog levels and digital/logical inputs are used in preprocessing. Other types of sensing such as capacitive is also possible. Appropriate grid work of conductors and electronics which is well known to those skilled in the art will- be used, entailing the use of digital and analog multiplexers, operational ' amplifiers polling elements and the like. In a pure

24
LCD cluster key arrangement, wherein a pressure sensor alone is the sensing element, in the trivial case where one uses a stylus, such as is done in the use of PDAs currently available in the market the sensing and interpretation is easy. These preceding devices do not work with fingers reliably since the keycaps are too small.
In the present invention, since there is a certain amount of shared "real estate" due to clustering, the user is intentionally allowed to press part of an adjacent key (principally the primary key while pressing a secondary key) . The present invention utilizes a distributed or wide area logical pressure sensor alone which provides a logical YES output for a selected positional area, or a low threshold central pressure sensor in combination with other detected readings such as an applied pressure, applied pressure rate, or shadowing. However, the pressure sensing area is mostly in a restricted smaller area around the center. The centers of the adjacent keys are located far enough apart that they result in one or more different levels of pressure generated by a pressing finger. The key associated with the higher level is selected as representing the fingertip which better represents the intended key. In the embodiment with the solar cell, the pressing of a key generates both an analog signal representing the amount of shadowing of a key cap by a operating finger and a digital/logical output which are used in preprocessing singly or in combination with the outputs from the pressure sensor. One approach involves picking for comparison of the shadowing levels only those keys whose pressure sensors have generated a logical YES and simultaneously picking for comparison of the pressure levels only those keys whose shadowing has generated a logical YES. In this scheme of preprocessing, at any stage upon identifying a

25
reliable output such as by the use of a logical AND of the pressure and shadow/solar cell sensors further processing is stopped. The early and reliable identification of an input precludes the activation or consideration of another input in this mutually exclusive electronic cluster key arrangement.
The invention is believed to reside in the cluster key per se, the various arrangements thereof, the combination of known electronic circuitry, and the overall combination of cooperating telephones, PDAs or the like including the Internet at large. Furthermore, the invention may be easily implemented in a manner that is compatible with the existing prior art in terms of user friendliness, such as allowing a user to operate a device in a numeric mode, an. alphabetic mode, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a front perspective view of a cluster key arrangement according to the present invention.
Fig. 2 is a top view of a mechanical cluster key arrangement according to the present invention configured in the form of a telephone.
Fig. 3 is a top view of a mechanical cluster key arrangement according to the present invention.
Fig. 4 is a side perspective view of a mechanical cluster key according to the present invention.
.Fig. 5 is an exploded^view of the mechanical cluster key shown in Fig.
Fig. 6A is a substrate electrical contact for the mechanical cluster key shown in Fig. 4 in accordance with the present invention.
Fig. 6B is a cross-sectional view of the substrate electrical contact shown in Fig.._ 6A.

26
Pig. 7 is a front perspective view of a mechanical cluster key arrangement according to the present invention.
Pig. 8A is an exploded perspective view of a cluster key from the cluster key arrangement shown in Fig. 7,
Pig. SB is a cross-sectional view of the cluster key shown in Fig. 8A.
Fig. 9 is a bottom view of the cluster key shown in Fig. 8A.
Pig. 10A is a front view of a mobile telephone with a touch screen LCD utilizing an electronic cluster key configuration according to the invention.
Fig. 10B is a front perspective view of a p-i-n junction amorphous silicon solar cell according to the invention.
Similar reference characters denote corresponding features consistently throughout the attached drawings.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
The present invention is a cluster key arrangement. The cluster key arrangement may be mechanically configured or electronically configured, A mechanical cluster key arrangement according to the invention is shown in Fig. 1, This mechanical cluster key arrangement 10 includes twelve cluster keys configured in an arrangement of three columns by four rows, such as conventionally found on standard telephones. This cluster key arrangement 10 may also be configured for use on cellular/mobile telephones, television remote controls, other handheld data entry devices, automotive controls, desktop/wall -mounted/cordless telephones, combination telephone recorders, PDAs, and other electronic devices. The cluster keys provide the user with the ability to select one of a plurality* of key elements representing numbers, letters.

27
symbols, functions, etc. , in a mutually exclusive manner.
The cluster keys shown in Fig. 1 each include a . primary key 12 surrounded by four secondary keys 14. However, a cluster key arrangement according to the invention may obviously include a primary key and any number of secondary keys, i.e., one, two, three, etc. The number of secondary keys is preferably in the range of four to eight. The cluster keys are preferably constructed from material giving a large range of hardness that may be needed to provide positive tactile feedback to the user. The primary key 12 for a particular cluster key preferably includes a dome or convex shaped button profile further shaped circularly, ellipsoidally, pentagonally, etc., as viewed from the top. The dome or convex shaped primary key profile as it reaches the vicinity of the associated secondary keys 14 assumes a concave profile. While a concave profile may be substituted for a dome, other button shapes, as viewed from the top, such as hexagonal, heptagonal, or octagonal may be substituted. The secondary keys 14 preferably each have a concave profile starting at the perimeter of the primary key somewhat underneath the primary key 12 in elevation and rises up in a concave arcuate profile to increase the contact surface area of the fingertip for better pressure distribution and ends with a greater width such as obtained by the wide end of a trapezoid, for providing a greater width to the finger to act on, and ends at an elevation which is slightly lower than the top elevation of the dome of the primary key 12, with which it is clustered. Other secondary key profiles, as viewed from the top, may include shapes such as rectangular, trapezoidal, semi-circular, which may be elongated to provide more finger contact.

28
The primary keys 12 are each labelled with a number, an asterisk symbol (*) , or a pound sign (#) . The secondary keys 14 are preferably nominally small in relation to the associated primary key 12 to accommodate space constraints. The secondary keys 14 preferably each include an arcuate concave surface which increases the surface area of contact for better pressure distribution at the finger tip of the user. Preferably, the outer edge of the secondary keys 14 flares out to provide a greater width on which a finger may act. The secondary keys 14 are each labelled with a function designation, letters, or character symbols.
Each primary key 12 has a first portion of the key exposed on a first side of the associated key cluster, and a second portion and third portion of the key exposed on a second side of the key cluster. When the first portion of a primary key 12 is depressed by a user, the second portion of the primary key 12 comes into contact with the second portions of the associated secondary keys with which it is clustered and mechanically mutually excludes any of the corresponding secondary keys' third portions of that particular key cluster from contacting a substrate such as a printed circuit board or an intermediate layer of an elastomeric sheet that has hat like protrusions with attached conductive elements under the hats to complete a circuit upon being depressed. If the primary key 12 of a cluster key is depressed, none of the associated secondary keys may contact the substrate. If a secondary key of a cluster key is depressed preferably neither the associated primary key nor the remaining associated secondary keys may contact the substrate. It is possible that if a secondary key is of a cluster key is depressed, at least two of the immediately adjacent secondary keys* will be precluded from acting on the substrate.

29
A perspective view and an exploded view of one of
these key clusters 100 is shown in Figs. 4 and 5,
wherein a primary key 101 is surrounded by four
secondary keys 104 that each pivot about a pivot axis
106. As shown, the primary key 101 includes a first
portion of the key exposed on a first side of the
associated key cluster, arid a second portion 103 and
third portion 102 of the key exposed on a second side
of the key cluster. If the primary key 101 of the
cluster key is depressed, none of the associated
secondary keys 104 may contact the substrate. If a
secondary key 104 of the cluster key is depressed
neither the associated primary key 101 nor preferably
the remaining associated secondary keys 104 may
contact the substrate, since secondary key mutual
exclusivity actuator 108 precludes it. However, it is
possible to mechanically configure a cluster key
arrangement wherein two secondary keys of a particular
cluster key may be simultaneously depressed. In that
case a processor operating in conjunction with the
cluster key arrangement would not generate a signal in
response to such activity, and may generate a error
signal to the user.
One technique for detecting a depressed condition of a key utilizes a capacitive key wherein a key circuit element forms two spaced apart metallic areas and one key and has a plated pad formed from a metal such as tin, nickel, or copper such that when the key end is brought in close proximity to the current element, a capacitive charge is noted by a keypad circuit board and a key-depressed state is acknowledged by a corresponding keyboard microprocessor and logic unit. An alternative construction incorporates a hardcontact keyboard, wherein the key has a stem which directly engages with the concave cavity, in close proximity with a pair of contacts comprising the circuit element which are then brought into electrically communicative

30
relationship therebetween. As shown in Figs. 6A and 6B, such a configuration for use in association with the cluster key shown in Figs. 4 and 5 include physical shell caps 160 on a flexible board 158 spaced from a circuit board 164 which includes metallic contacts 166. The shell caps 160 each include a metallic element 162 within the cap 160. When a user presses one button of a selected cluster key, a signal is generated when the key bottom of the key presses a shell cap 160 and causes the associated metallic element 162 to contact a metallic contact 166.
A mechanical cluster key arrangement configured for use on a remote telephone 2 0 is shown in Fig. 2 which includes a housing 22, a speaker 24, and a microphone 26. The housing 22 also includes a liquid crystal display (LCD) 28. Openings in the housing are provided for the individual cluster keys. In addition, although not shown, the remote telephone 20 may also include a buzzer, indicator lights, and other features, depending upon a particular design or model. The remote telephone 20 includes a main printed circuit board (not shown) which includes all of the major radio frequency (RF) and logic circuits required to provide at least basic cellular telephone service and support a variety of features. Such circuits typically include a plurality of chips, integrated circuits, and other components interconnected formed within, or on 'the surface, of the printed circuit board. The > remote telephone 20 also includes an antenna 30 that extends through an aperture provided in the housing 22 and is electrically connected to the printed circuit board. The housing 22 encloses a substrate on which are mounted the closing switches and the dial pulse circuit which is controlled by these switches. Upon reception of RF signals, the mobile telephone 20 receives the RF signals through the antenna 30. The antenna 30 converts the received

31
RF signals into electrical RF signals for use by the radio circuitry. The radio circuitry demodulates the electrical RF signals and recovers the data transmitted using the RF signals. Additionally, the radio circuitry outputs the data to a processor. The processor includes at least a main processor and associated memory as well as other control circuits including integrated circuits or other known technologies. The processor formats the data output from the radio circuitry into a recognizable voice or message information for use by the user interface. The user interface communicates the received information or voice to a user through the use of the speaker 24 and the display 28. All digital or all analog or combinations of analog and digital network based cellular telephone services are possible.
Unlike present analog systems and other digital systems that divide the available spectrum into narrow channels and assign one or more conversations to each channel, CDMA is a wideband spread spectrum technology that spreads multiple conversations across a wide segment of the broadcast spectrum. Each telephone or data call is assigned a unique code that distinguishes it from the multitude of calls simultaneously transmitted over the same broadcast spectrum. So long as the receiving device has the right code, it can pick its conversation' out-from all the others.
The mechanical cluster keys*- shown in Fig. 2 each include a primary key 32 and five secondary keys. As stated before, a cluster key arrangement according to the invention may obviously include a primary key and any number of secondary keys, i.e. one, two, three, etc. The selected number of secondary keys is preferably in the range of four to eight* The cluster keys are preferably constructed from material giving a large range of hardness that may be needed to provide positive tactile feedback to the user. The

32
primary key 32 for a particular cluster key preferably includes a dome or convex shaped button profile further shaped circularly, ellipsoidally, pentagonally, etc., as viewed from the top. The dome or convex shaped primary key profile as it reaches the vicinity of the associated secondary keys assumes a concave profile. While a concave profile may be substituted for a dome, other button shapes, as viewed from the top, such as hexagonal, heptagonal, or octagonal may be substituted. The associated secondary keys each preferably have a concave profile starting at the perimeter of the primary key somewhat underneath the primary key in elevation and rises up in a concave arcuate profile to increase ' the contact surface area of the fingertip for better pressure distribution and ends with a greater width such as obtained by the wide end of a trapezoid, for providing a greater width to the finger to act on, and ends at an elevation which is slightly lower than the top elevation of the dome of the primary key, with which it is clustered. Other secondary key profiles, as viewed from the top, may include shapes such as rectangular, trapezoidal, semi-circular, which may be elongated to provide more finger contact.
The primary keys 32 are each labelled with a number, an asterisk symbol (*) t or a pound sign (#5 . The secondary keys are each labelled with a function designation, letters, or character symbols. In this mechanical cluster key arrangement, the primary key labelled "l" is surrounded by unmarked secondary keys 34,35,38,40 and a secondary key labelled with "I" . While the secondary keys 34,36,38,40 may obviously be labelled according to the desires of the user, preferably secondary key 34 is labelled HCLR", secondary key 36 is labelled "YES/SEND" , secondary key 38 is labelled WPWR ON/OFF", and secondary key 40 is1 labelled "NO/END" . Each key is disposed within the

33
housing. The primary key labelled "4" includes an unmarked secondary key 42 which is preferably labelled "CTRL". The primary key labelled "5" includes an unmarked secondary key 44 which is preferably labelled "ALT" . The primary key labelled "6" includes an unmarked secondary key 46 which is preferably labelled "ENTER" . The primary key labelled "8" includes an unmarked secondary key 48 which is preferably labelled with an accent mark. The primary key labelled "0" includes an unmarked secondary key 50 which is preferably labelled "SPACE BAR". The primary key labelled "#" includes an unmarked secondary key 52 which is preferably labelled with an underscore. The primary key labelled "#" also includes another unnumbered unmarked secondary key which is preferably labelled "MODE" . Each key has a first portion of the key exposed on a first side of the housing and a second portion of the key exposed on a second side of the housing. When the first portion of a key is depressed by a user, the second portion of the key comes into contact with a substrate and mechanically mutually excludes any of the corresponding keys of that particular key cluster from contacting the substrate. These cluster keys function in the same manner as the cluster key shown in Figs. 4 and 5, wherein a primary key is surrounded by secondary keys which pivot about a pivot axis. If the primary key of a cluster key is depressed, none of the associated secondary keys may contact the ^substrate. If a secondary key of a cluster key is depressed preferably neither the associated primary key nor the remaining associated secondary keys may contact the substrate. It is possible that if a secondary key of a cluster key is depressed, at least two of the immediately adjacent secondary keys will be precluded from acting on the substrate on account of secondary key mutual exclusivity actuator 108.

34
One technique for detecting a depressed condition of a key utilizes a capacitive key wherein the key circuit element forms two spaced apart metallic areas and has a plated pad formed from a metal such as tin, nickel, or copper such that when the key end is brought in close proximity to the current element, a capacitive charge is noted by the circuit board and a key-depressed state is acknowledged by a corresponding keyboard microprocessor and logic unit. An alternative construction incorporates a hardcontact keyboard, wherein the key has a stem which directly engages with the concave cavity, in close proximity with a pair of contacts comprising the circuit element which are then brought into electrically communicative relationship therebetween, previously described.
Another mechanical cluster key arrangement 60 according to the invention is shown in Pig. 3. The cluster keys in this cluster key arrangement 60 each include a primary key 62 surrounded by six secondary keys. As stated above, a cluster key arrangement according to the invention may obviously include a primary key and any number of secondary keys, i.e., one, two, three, etc. The number of secondary keys is preferably in the range of four to eight. The cluster keys are preferably constructed from material giving a large range of hardness that may be needed to provide positive tactile feedback to the user. The primary key for a particular cluster key preferably includes a dome or convex shaped button profile further shaped circularly, ellipsoidally, pentagonally, etc., as viewed from the top. The dome or convex shaped primary key profile as it reaches the vicinity of the associated secondary keys assumes a concave profile. While a concave profile may be substituted for a dome, other button shapes, as viewed from the top, such as hexagonal, heptagonal, or octagonal may be substituted. The secondary keys each

35
have a concave profile starting at the perimeter of the primary key somewhat underneath the primary key in elevation and rises up in a concave arcuate profile to increase the contact surface area of the fingertip for better pressure distribution and ends with a greater width such as obtained by the wide end of a trapezoid, for providing a greater width to the finger to act on, and ends at an elevation which is slightly lower than the top elevation of the dome of the primary key, with which it is clustered. Other secondary key profiles, as viewed from the top, may include shapes such as rectangular, trapezoidal, semi-circular, which may be elongated to provide more finger contact. The primary keys 62 are each labelled with a number, an asterisk symbol (*), or a pound sign (#) . The secondary keys are each labelled with a function designation, letters, or character symbols. Each key is disposed within the housing. In this cluster key arrangement, the primary key 62 labelled "1" is surrounded by unmarked secondary keys 64,66. While the secondary keys 64,66 may obviously be labelled according to the desires of the user, preferably secondary key 64 is labelled "NO/END", and secondary key 56 is labelled "YES/SEND". The primary key labelled "2" includes an unmarked secondary key 68 which is preferably labelled "MODE". The primary key labelled M3" includes an unmarked secondary key 70 which is preferably labelled "ENTER". The primary key labelled "8" includes an unmarked secondary key 72 which is preferably labelled "ALT". The primary key labelled vv*" includes an unmarked secondary key 74 which is preferably labelled "F10" . The primary key labelled "*" also includes an unmarked secondary key 76 which is preferably labelled " CTRL". The primary key 1abelied "0" include s an unmarked secondary key 78 which is preferably labelled "Fll" . The primary key labelled M#" includes an unmarked secondary key 80 which is preferably labelled

36
WF12". The primary key labelled "#" also includes an unmarked secondary key 82 which is preferably labelled "SPACE BAR". The primary key labelled "#" also includes another unnumbered unmarked secondary key which is preferably labelled "MODE". Each key has a first portion of the key exposed on a first side of the housing and a of the key exposed on a second side of the housing. When the first portion of a key is depressed by a user, the of the key comes into contact with a substrate and mechanically mutually excludes any of the corresponding keys of that particular key cluster from contacting-the substrate. These cluster keys function in the same manner as the cluster key shown in Figs. 4 and 5, wherein a primary key is surrounded by secondary keys which each pivot about a pivot axis. If a primary key 62 is depressed, none of the secondary keys associated with that key cluster may contact the substrate. If a secondary key is depressed neither the primary key nor the remaining secondary keys may contact the substrate.
One technique for detecting a depressed condition of a key utilizes a capacitive key wherein a key circuit element forms two spaced apart metallic areas and one key and has a plated pad formed from a metal such as tin, nickel, or copper such that when the key end is brought in close proximity^to the current element, a capacitive charge "is noted by^ a1 .keypad circuit board and a key-depressed state is^ \acknowledged by a corresponding, keyboard microprocessor and logic unit. An alternative construction incorporates a hardcontact keyboard, wherein the^key has a stem which directly engages with the concave cavity, in close proximity with a pair of contacts comprising the circuit element which are then brought into electrically communicative relationship therebetween.
Another mechanical cluster key arrangement 110K according to the invention is shown in Fig. 7. The

37
cluster keys in this cluster key arrangement 110 each include a primary key 112 circularly surrounded by a concave shaped secondary key 116, as more particularly shown in Figs. 8A, 8B, and 9. The various possible shapes attributed to the primary and secondary keys in previously described mechanical cluster key arrangements are also possible in this mechanical cluster key arrangement. The cluster keys in this mechanical cluster key arrangement are preferably constructed from material giving a large range of hardness that may be needed to provide positive tactile feedback to the user. As before, typically, the primary keys 112 are each labelled with a number, an asterisk symbol (*) , or a pound sign (#) . The secondary keys 116 are each labelled with at least one function designation, letter, or character symbol. Each key has a first portion of the key exposed on a first side of the cluster key assembly 110 and a of . the key exposed on a second side of the cluster key assembly 110. When the first portion of a key is depressed by a user, the of the key comes into contact with a substrate and mechanically mutually excludes any functions associated with the corresponding secondary key of that particular key cluster from contacting the substrate. If a primary key 112 is depressed'^ .the secondary key 116 associated with that key cluster may contact the substrate. If a secondary key 116 is depressed the primary key 112 may not contact the substrate.' As shown in Fig. 9, each secondary key 116 includes a convex bottom surface 118 which includes electrical traces 119 corresponding to the number of functions designated on the concave upper surface 117 of the secondary key 116. Selection of one function mutually precludes the selection of the other secondary key functions or the primary key 112 function.

38
One technique for detecting a depressed condition of a key utilizes a capacitive key wherein a key circuit element forms two spaced apart metallic areas and has a plated pad formed from a metal such as tin, nickel, or copper such that when the key end is brought in close proximity to the current element, a capacitive charge is noted by a keypad circuit board and a key-depressed state is acknowledged by a corresponding keyboard microprocessor and logic unit. An alternative construction incorporates a hardcontact keyboard, wherein the key has a stem which directly engages with the concave cavity, in close proximity with a pair of contacts comprising the circuit element which are then brought into electrically communicative relationship therebetween.
Each key has a first portion of the key exposed on a first side of the cluster key assembly, and a second and third portion of the key exposed on a second side of the cluster key assembly. When the first portion of a key is depressed by a user, the third portion of the key comes into contact with a substrate while its second portion mechanically mutually excludes any functions associated with the corresponding secondary key of that particular key cluster from contacting the substrate.
The primary key 112 travels through a stepped hole in the key cluster. When the primary key 112 is actuated, a shoulder 114 on the primary key 112 mates with steps 119 in the associated secondary key 116. This engagement of the shoulder 114 of the primary key 112 with steps in the secondary key 116 traps the secondary key 116 against the substrate and prevents it from rotating and rolling over the surface of the substrate. Since the secondary key 116 is actuated by rotating and rolling over the substrate, the secondary key 116 can not be actuated when the primary key 112» is actuated.

39
When a secondary key 116 is actuated by rotating and rolling over the surface of the substrate, it positions the associated primary key 112 at an angle with the substrate. If the associated primary key 112 is then depressed, this angle will cause the edge of the primary key 112 to contact the substrate and prevent the bottom face 115 of the primary key 112 from making contact. Since actuation of the primary key 112 is produced by the bottom face 115 contacting the substrate, this prevents actuation of the primary key 112 when the associated secondary key 116 is actuated.
An electronic cluster key arrangement according to the invention is shown in Fig. 10A. This cluster key arrangement is electronically configured in the form of a touch screen liquid crystal display (LCD) 132 mounted within a remote telephone 120 which includes a housing 122, a microphone 124, and a speaker 126. Obviously, this electronically configured touch screen LCD cluster key arrangement may also be configured for use on cellular/mobile telephones, television remote controls, other handheld data entry devices, automotive controls, desktop/wall-mounted/cordless telephones, combination telephone recorders, PDAs, and other electronic devices, according to the desires of the user.
The cluster keys in this electronic configuration are preferably displayed in the form of circular, ellipsoidal, pentagonal, etc., images as viewed from the top. The secondary keys each preferably displayed in the form of rectangular, trapezoidal, semi-circular, images which may be elongated to provide more finger contact. The preceding images may be similar to those shown in Figs. 1, 2, 3, and 7. The housing 122 also includes a liquid crystal display (LCD) 130 for displaying information for the user, a power switch 134, and a mode switch 136. The touch

40
screen LCD may be any conventionally configured touch screen LCD. For example, the touch screen LCD may be configured in the form of an upper glass sheet and a lower glass sheet with a thin layer of liquid crystal material including a pressure sensing element sandwiched between the glass sheets. However, the touch screen LCD may also be configured in combination with a transparent thin film solar cell such as a p-i-n junction type amorphous silicon solar cell 140, as shown in Fig. 10B.
Many approaches to the determination of the location of X and Y coordinates of a touch point based on sensing pressure are well known. A pressure-sensitive input device comprising an X-coordinate detection resistive element connected to mutually parallel vertical conductors and a Y-coordinate detection resistive element connected to mutually parallel horizontal conductors, for detecting the position of a point depressed by a stylus or the like, works by detecting changes in the resistance values of these resistive elements. Switches are used for on-off control of the current flowing into or out of both ends of the X-coordinate detection resistive element and the Y-coordinate detection resistive element, and a voltage detection circuit detects the voltage between the X-coordinate detection resistive element and the Y-coordinate detection resistive element. Multiple inputs can be detected based on the results from the voltage detection circuit when the currents are switched by the switches.
The preceding is but one approach to pressure sensing based location.determination known in the art. A more sensitive "smart sensor" type micro-strain gage based localized point sensor located at the midpoint of the keycaps of the primary keys and at the midpoint of the , secondary keycaps, located along the circumference of a circle which constitutes the

41
"virtual circle" along which lie the locus of the centers of the secondary keys of the various electronic arrangements. This sensitive pressure sensor can output an analog pressure level and its digitized digital equivalent and likewise the rate of change of pressure and its digitized equivalent. The sensor is a smart sensor in that it can be embedded in the carrier material.
The touch screen LCD 132 could be of the monochromatic type or an active matrix full color display. As is known widely to those skilled in the art, an active matrix generally consists of two sheets between which is inserted an electro-optical material such as a liquid crystal. On one of the sheets is a matrix of transparent conductive blocks, thin film transistors, a group of conducting addressing lines, and a group of conductive addressing columns. Each transistor has a gate connected to a line, a source connected to a block, and a drain connected to a column. On the second sheet is a counter electrode. On top of the liquid crystal material is attached a flexible transparent film which has patterned thin film semiconductor layers preferably comprising a layer of i(intrinsic)-type semiconductor disposed between a layer of p-type semiconductor and a layer of n-type semiconductor. The p-i-n layer is further sandwiched on either side by a thin layer of transparent conductive layer such as tin oxide, indium tin oxide, pr the like-to constitute a p-i-n junction
amorphous silicon*sol'ar cell.*"**^
/ ¦ ^ A silicon solar cell connected to the emitter of a
• !
common base amplifier biased so that the cell voltage
is near to zero, *a: short-circuit load can be used as a sensor. Collector^lbacU is three forward diodes which develop an approximately logarithmic voltage versus current in the current ranges involved. The ( next stage provides the AC coupling for the pulses, so

42
that the sensitivity of the sensing system is essentially independent of the light level on the cell. This stage is an operational amplifier with a bypass on the feedback for high AC gain and low direct current DC gain. This network also has a low-pass net to reject noise spikes picked up from the environment. The coverage of the conductive layers by an actuating finger causes shadowing which results in a decreased current output proportional to the area shadowed.
A preferable p-i-n junction amorphous silicon solar cell 140 is shown in Fig, 10B. This p-i-n junction amorphous silicon solar cell 140 includes nine layers 141-149 . Layer 141 is a transparent conductive tin oxide layer. Layer 142 is a transparent layer of p~type semiconductor. Layer 143 is a transparent layer of i-type semiconductor. Layer 144 is a transparent layer of n-type semiconductor. Layer 145 is a transparent conductive tin oxide layer. Layer 146 is a transparent insulating silicon-dioxide layer. Layer 147 is a transparent layer containing a horizontal or vertical electrical grid. Layer 148 is a transparent insulating silicon-dioxide layer. Layer 149 is a transparent layer containing a horizontal or vertical electrical grid. Once this p-i-n junction amorphous silicon solar cell 140 is attached to an LCD, the solar cell 140 is covered with a transparent plastic layer to protect the cell from the environment. In actuality the solar cell and associated layers are deposited on the plastic layer which is then inverted and attached to the glass.
The p-i-n j-unction amorphous silicon solar cell is scribed into smaller portions comprising one primary portion and at least one peripheral secondary portion (preferably four secondary-portions around the primary portion) to configure an electronic cluster key. The p-i-n junction amorphous silicon solar cell include at. least one vertical and horizontal grid of transparent

43
conductors laid in between two transparent insulating ' layers of the thin film variety such as silicon dioxide. The p-i-n junction amorphous silicon solar cell's two conductive transparent coatings of tin oxide, indium tin oxide, or the like, can be combined in series using techniques well known to persons skilled in the art to provide a trickle charge at approximately 12-14 volts. One approach to series connection entails using a laser to scribe and separate the initial tin oxide coating into islands, using a photoresist mask on the edge to prevent the subsequent layers of p,i,n from touching the conductive layer. Thereafter, the mask is removed and the second tin oxide layer is applied which connects the top surface of the second cell to the bottom surface of the first cell, resulting in a series connection. Other intervening steps are well known to those skilled in the art. The p-i-n junction amorphous silicon solar cell may include capacitors and/or pressure sensors at the center of each key which are all deposited on a flexible transparent substrate such as Kapton and then glued on to the LCD. Kapton or other high temperature plastic is used to withstand high temperatures associated with chemical vapor deposition of amorphous silicon. It is possible to integrate the processing of the solar cell and the LCD based on active matrix thin film transistors (TFTs).
The LCD is preferably an active matrix TFT display which preferably displays the primary key as a white key with black characters for most contrast and which preferably displays the secondary key alphabet characters in a particular color such as red. Preferably secondary key function symbols are displayed in green, secondary key characters such as the AT sign (@) are displayed in blue, and secondary* key control symbols such as YES/SEND are displayed in

44
yellow with green letters and NO/END are displayed in yellow with red letters. Obviously, a variety of other color assignments are possible.
The cluster key arrangement is configured utilizing a keyboard emulator within the remote telephone in accordance with the mode selected by the user using the mode switch. Fig. 10A illustrates one arrangement showing a cluster key arrangement comprising a set of twelve cluster keys arranged in four rows by three columns. The primary key for a particular cluster key is preferably displayed in the form of a circularly, ellipsoidally, pentagonally, etc., shaped image as viewed from the top. The secondary keys are each preferably displayed in the form of a rectangularly, trapezoidally, or semi-circularly, shaped image which may be elongated to provide more finger contact. Each electronically configured cluster key includes a primary key location 13 8 surrounded by at least one secondary key location 140. By touching a particular key location on the touch screen LCD 132, the user activates an electrical signal which passes through an electrical matrix formed by a plurality of contact lines 142 interconnecting each of the particular key locations. The electrical signal is delivered to a processing unit stored within the remote telephone 120, which is then converted into a symbol and displayed on the"LCD 130. The remote telephone also includes circuitry which precludes the simultaneous activation of more than one key location of a particular cluster key.
The electronic or opto-electrpnic mutually exclusive cluster key arrangement works on the same basis of preprocessing as was done in the mechanical cluster key arrangements wherein only one signal could be generated at a time. In the electronic cluster key arrangement the preprocessing is based on sensing one1 or more variables such as contact pressure or

45
shadowing of a solar cell's microcell element. Both analog levels and digital/logical inputs are used in preprocessing. Other types of sensing such as capacitive is also possible. Appropriate grid work of conductors and electronics which is well known to those skilled in the art will be used, entailing the use of digital and analog mutiplexers, operational amplifiers polling elements and the like. in a pure LCD cluster key arrangement, wherein a pressure sensor alone is the sensing element, in the trivial case where one uses a stylus, such as is done in the use of PDAs currently available in the market place called "Palmtops" (made by 3Com, Hewlett Packard, Casio, Philips, etc.) the sensing and interpretation is easy. These devices utilize a distributed or wide area logical pressure sensor which provides a logical YES output for a selected positional area. These preceding devices do not work with fingers reliably since the keycaps are too small.
In the present invention, since there is a certain amount of shared "real estate" due to clustering, the user is intentionally allowed to press part of an adjacent key (principally the primary key while pressing a secondary key. Many approaches to the determination of the location of X and Y coordinates of a touch point based on sensing pressure are well known- A pressure sensitive input device comprising an X-coordinate detection resistive element connected to mutually parallel vertical conductors and a Y-coordinate detection resistive element connected to mutually parallel-horizontal conductors, for detecting the position of a point depressed by a stylus or the like, works by detecting changes in the resistance values of these resistive elements.
The present invention utilizes either a distributed or wide area logical pressure sensor alone which, provides a logical YES output for a selected

46
positional area, or a low threshold central pressure sensor in combination with other detected readings such as an applied pressure, rate of applied pressure, or shadowing. Switches are used for on-off control of the current flowing into or out of both ends of the X-coordinate detection resistive element and the Y-coordinate detection resistive element, and a voltage detection circuit detects the voltage between the X-coordinate detection resistive element and the Y-coordinate detection resistive element. Multiple inputs can be detected based on the results from the voltage detection circuit when the currents are switched by the switches.
The preceding is but one approach to pressure sensing based location determination known in the art. A more sensitive "smart sensor" type micro-strain gage based localized point sensor located at the midpoint of the keycaps of the primary keys and at the midpoint of the secondary keycaps (the midpoints are mildly textured to facilitate tactile feedback without optical degradation), located along the circumference of a circle which constitutes the "virtual circle" along which lie the locus of the centers of the secondary keys of the various electronic arrangements. This sensitive pressure sensor can output an analog pressure level and its digitized digital equivalent and likewise the rate of change of pressure and its digitized equivalent. The sensor is a smart sensor in that it can be embedded in the carrier material.
The first level of mutual exclusivity is rather trivial. The system logic will not accept inputs from two different cluster keys; such dual activation attempt will occur when a user inadvertently presses two adjacent secondary keys belonging to two different clusters (the system will output an error message and sound a beep asking the user to move the finger a l little closer to the center of the cluster) . It can

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also occur when one purposely tests the system by
pressing keys from clusters that are not adjacent
(this will merely elicit a beep and optional error
message). Once the finger is operating within a
cluster, the finger perhaps overlaps a little over let
us say 3 keys.... The intended secondary key (let us
say the alphabet B) , the corner of the primary key
(which is the number 2) and a portion of the adjacent
secondary key (say the letter A)... under these
circumstances, the pressure sensor that is distributed
over the entire "keycap" areas of both the secondary
keys and the primary key will generate a logical YES
for these keys. However, the more sensitive pressure
sensor located in the middle (lower threshold) will in
most instances have an output only in the intended
secondary key of B. This output in reality has two
components, an analog level (or its digitized
equivalent) representing the amount of or relative
amount of pressure (this is likely to be the highest
in the intended secondary key since presumably the
finger tip is acting on it. For further reliability,
a rate input will also be generated in identical
fashion. When uniqueness is established the logical
outputs from the other two keys are precluded from
proceeding further. A simple implementation would
accomplish this inside the box with conventional
electronics. It is also possible to implement this in
solid state or monolithic way by opening the
conductive pathway from the non intended keys thus
making it mutually exclusive. It is noted that a
second pressure sensor, i.e., the.generalized pressure
sensor also needs to be there, for another case, i.e.
when one attempts to provide a very clean input by
using a pen tip or stylus as is done on Palmtops these
days. Of course they are doing it because the current
art is deficient in that it provides no choice of«

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finger actuation because the keycaps are based on the emulation of QWERTY type keys which are tiny.
However, the pressure sensing area is mostly in a restricted smaller area around the center. The centers of the adjacent keys are located far enough apart that they result in one or more different levels of pressure generated by a pressing finger. The key1 associated with the higher level is selected as representing the fingertip which better represents the intended key. In the embodiment with the solar cell, the pressing of a key generates both an analog signal representing the amount of shadowing of a key cap by a operating finger and a digital/logical output which are used in pre-processing singly or in combination with the outputs from the pressure sensor. One approach involves picking for comparison of the shadowing levels only those keys whose pressure sensors have generated a logical YES and simultaneously picking for comparison of the pressure levels only those keys whose shadowing has generated a logical YES. In this scheme of preprocessing, at any stage upon identifying a reliable output such as by the use of a logical AND of the pressure and shadow/solar cell sensors further processing is stopped. The early and reliable identification of an input precludes the activation or consideration of another input in this mutually exclusive electronic cluster key arrangement.
It is to be-understood that the present invention is not limited *tb the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

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I CLAIM :
1. A cluster key arrangement comprising :
at least one cluster key, said cluster key comprising :
a single primary key;
at least one secondary key, said secondary key being located immediately adjacent to said primary key of said cluster key ; and
mutual exclusivity selecting means for selecting said primary key or said secondary key in a mutually exclusive manner;
wherein when both said primary key and said secondary key have met a threshold for actuation close in time to each other, said mutual exclusivity selecting means utilizes an order of activation and at least one difference between said primary key and said secondary key other than the order of activation to select between said primary key and said secondary key ;
each of said primary and secondary keys is individually actuabie ;
each of said primary key and said secondary key upon actuation move in a direction substantially parallel to the motion of the other of said primary and said secondary key upon actuation.
2. A cluster key arrangement as claimed in claim 1, wherein :
each of said primary and secondary keys is arranged on a planar surface; and
each of said primary and secondary keys upon actuation moves in a direction substantially perpendicular to said planar surface.
3. A cluster key arrangement as claimed in claim 1, wherein each of said
primary key and said secondary key has a button profile having an arcuate shape,
said arcuate shape being selected from the group consisting of dome shaped,
convex, trough, and concave.
4. A cluster key arrangement as claimed in claim 1, wherein said primary key
has a top view which is shaped circularly, ellipsoidally, pentagonalty, hexagonally,

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heptagonally, or octagonally, the number of secondary keys is at least two, and said secondary keys are spaced about said primary key:
5. A cluster key arrangement as claimed in claim 1, wherein :
the number of said cluster keys is at least two ;
each said primary key has a primary key label, each primary key label having at least one primary key symbol selected from the group consisting of numerals, an asterisk symbol, and a pound sign ;
each said secondary key has a secondary key label, each secondary key label having at least one secondary key symbol selected from the group consisting of alphabetic characters and function designations.
6. A cluster key arrangement as claimed in claim 1, wherein each said cluster
key is separated by a gap from any other of said cluster keys.
7. A cluster key arrangement as claimed in claim 1, wherein each said
primary key and each said secondary key has a top surface and an opposing'
underside surface;
each said top surface has a first portion ;
each said underside surface has a second portion and a third portion ;
said third portion of each said key is positioned with respect to the top surface of said key such that if a user applies pressure to the top surface of said key, said key will be activated through said third portion ; and
said second portion of each said key is connected through a mutual exclusivity actuator to said second portion of at least one adjacent key of said keys, such that when the user presses one of said keys, said second portion of said pressed one of said keys interacts with said second portion of said adjacent key to preclude said adjacent key from being activated.

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8. A cluster key arrangement according to claim 1, wherein said mutual
exclusivity selecting means uses differences in pressure to select between said
primary key and said secondary key.
9. The cluster key arrangement as claimed in claim 1, wherein said mutual
exclusivity selecting means uses differences in shadowing to select between said
primary key and said secondary key.
10. A cluster key arrangement as claimed in claim 1, wherein the number of
said secondary keys in each of said at least one cluster key is at least four.
11. A cluster key arrangement as claimed in claim 1, wherein said secondary
key is smaller in surface area than said primary key.
12. A cluster key arrangement as claimed in claim 1, wherein the number of
said secondary keys in each said cluster key is at least two, and said mutual
exclusivity selecting means selects between each said secondary key of each
said cluster key in a mutually exclusive manner.
13. A cluster key arrangement as claimed in claim 1, wherein :
said primary key has a single conductive pathway associated with said primary key, said conductive pathway associated with said primary key being normally open;
said secondary key has a single conductive pathway associated with said secondary key, said conductive pathway associated with said secondary key being normally open ; wherein
said conductive pathway associated with said primary key is closed when said primary key is selected, and said conductive pathway associated with said secondary key is closed when said secondary key is selected.

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14. A cluster key arrangement as claimed in claim 1, in combination with an
electronic device, said electronic device being selected from the group consisting
of a telephone, a remote control, a computer, and a personal digital assistant;
wherein the number of cluster keys is twelve ;
the functions of said electronic device are controlled by said primary and. secondary keys of said cluster keys ; and
said combination has no keys other than said primary and secondary keys of said twelve cluster keys.
15, A cluster key arrangement as claimed in claim 1, in combination with an
electronic device, said electronic device being selected from the group consisting
of a telephone, a remote control, a computer, and a personal digital assistant ;
wherein:
said electronic device has a liquid crystal display;
said cluster key arrangement comprises at least two secondary keys; and
at least two of said secondary keys are arrow keys.
18, A cluster key arrangement as claimed in ciaim 15, wherein each of said secondary keys has an associated embedded smart sensor.
17. A cluster key arrangement as claimed in claim 1,
wherein said cluster key arrangement comprises at least two secondary keys; and
at least one of said secondary keys is a mode key.
18. A cluster key arrangement as claimed in claim 1, wherein :
the number of cluster keys is at least twelve ;
twelve of said at least twelve cluster keys are configured in an arrangement of three columns by four rows ;
at least one of said cluster keys comprises at least four secondary keys ;

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each said primary key has at feast one primary key label, each primary key label including at least one primary key symbol selected from the group consisting of numerals, an asterisk symbol, and a pound sign ;
each said secondary key has at least one secondary key label, each secondary key label having at least one secondary key symbol selected from the group consisting of alphabetic characters and function designations.
19. A cluster key arrangement as claimed in claim 18»
wherein each of said cluster keys comprises at least four secondary keys ; at least one of said secondary keys is a mode key; and said cluster key arrangement emulates a standard keyboard.
20. A cluster key arrangement as claimed in claim 18, wherein said numerals
are selected from the group consisting of ten numbers from 0 to 9, and wherein
said alphabetic characters are selected from the group consisting of 26 letters
from A to Z.
21. A cluster key arrangement as claimed in claim 20, wherein said four rows
include a top row, and said primary keys of said three columns of said top row are
labelled 1, 2, and 3 respectively from left to right.
22. A cluster key arrangement as claimed in claim 21, wherein :
said cluster key of said primary key labelled 2 of said top row comprises secondary keys labelled A, B, and C , and
said secondary key labelled A is located at the upper left of said primary key labelled 2 of said top row.
23. A cluster key arrangement as claimed in claim 1, wherein :
said mutual exclusivity selecting means comprises a preprocessor, and said preprocessor has at least one configuration selected from the group consisting of an electronic configuration and an opto-electronic configuration.

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24. A cluster key arrangement as claimed in Claim 23, wherein said primary
key is pentagonally shaped, the number of secondary keys in each cluster key is
five, and said five secondary keys are circumferentially distributed about the five
sides of said primary key.
25. A cluster key arrangement as claimed in claim 23, comprising an integrated
pressure sensing element.
26. A cluster key arrangement as claimed in claim 23, comprising a p-t-n
junction amorphous silicon solar cell with two conductive transparent coatings.
27. A cluster key arrangement as claimed in claim 23, comprising a conductive
grid,
28. A cluster key arrangement as claimed in claim 23, comprising a
mechanical cluster key configuration.
29. A cluster key arrangement as claimed in claim 23, wherein the
preprocessor comprises electronics that use differences in pressure to select one
of said primary keys or one of said secondary keys over an adjacent one of said
primary and secondary keys.
30. A cluster key arrangement as claimed in claim 23, wherein said mutual
exclusivity selecting means comprises an embedded smart sensor.
31. A cluster key arrangement as claimed in claim 23, wherein said cluster key
arrangement is electronically configured in the form of a touch screen liquid
crystal display.
32. A cluster key arrangement as claimed in claim 31, wherein said touch
screen liquid crystal display is an active matrix thin film transistor display.

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33. A cluster key arrangement as claimed in claim 32, comprising a layer of i-
type semiconductor disposed between a layer of p-type semiconductor and a
layer of n-type semiconductor,
34. A cluster key arrangement as claimed in claim 33, comprising two
conductive transparent coatings of tin oxide or indium tin oxide to provide two
layers, wherein said layers are capable of being combined in series to provide a
trickle charge.
35. The cluster key arrangement as claimed in 1, comprising at least one
additional cluster key, wherein the cluster keys are located adjacent each other so
as to form a row.
36. The cluster key arrangement as claimed in claim 1, comprising at least two
additional cluster keys, wherein the primary keys of the cluster keys are located
adjacent each other so as to form a row.
37. The cluster key arrangement as claimed in claim 1, wherein said primary
key and said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user.
38. A cluster key arrangement as claimed in claim 1, comprising a display; and
wherein :
each primary key and each secondary key has at least two thresholds for actuation, said thresholds for actuation including a first threshold and a second threshold for each said primary and secondary key ;
each said first threshold for each said primary and secondary key requires less pressure for actuation than said second threshold for the same key of said primary and secondary keys ;

56
reaching said second threshold for each of said primary and secondary keys results in a keystroke being recognized ;
reaching said first threshold for each of said primary and secondary keys does not result in a keystroke being recognized ;
reaching said first threshold for each of said primary and secondary keys results in a sensory feedback signal perceptible to a user of said cluster key arrangement; and
said first threshold comprising a variable region, said first threshold being measurably higher than zero and measurably lower than said second threshold.
39. A cluster key arrangement as claimed in claim 38, wherein a
predetermined set of logical rules is utilized to preprocess an output signal for
each of said primary and secondary keys between reaching said first threshold
and reaching said second threshold.
40. A cluster key arrangement comprising :
at least one cluster key, said cluster key comprising :
a single primary key ;
at least one secondary key, said secondary key being located adjacent to said primary key of said cluster key ; and
a mutual exclusivity actuator for selecting said primary key or said secondary key in a mutually exclusive manner;
wherein each said cluster key has a support structure supporting said cluster key;
said mutual exclusivity actuator interacts with said support structure of said cluster key, such that a user may mutually exclusively select between said primary key and said secondary key ;
each of said primary and secondary keys is individually actuable ;
each of said primary key and said secondary key upon actuation move in a direction substantially parallel to the motion of the other of said primary key and said secondary key upon actuation ;

57
each of said primary key and said secondary key has an electrical contact, activation of each said electrical contact sends a signal which indicates an input from said cluster key arrangement, and said mutual exclusivity actuator selects between said primary key and said secondary key during preprocessing.
41. The cluster key arrangement as claimed in claim 40, comprising at least
one additional duster key, wherein the cluster keys are located adjacent each
other so as to form a row.
42. The duster key arrangement as claimed in claim 40, comprising at least
two additional cluster keys, wherein the primary keys of the duster keys are
located adjacent each other so as to form a row.
43. The duster key arrangement as claimed in claim 40, wherein said primary
key and said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user,
44. A cluster keyboard comprising :
at least one cluster key, said cluster key comprising :
a primary key, said primary key having a first support structure that supports the primary key ;
at least one secondary key, said secondary key being located immediately adjacent to said primary key of said cluster key, said secondary key having a second support structure that supports the secondary key ;
a mutual exclusivity actuator, said * mutual exclusivity actuator interacting with said first support structure of said primary key and with said second support structure of said secondary keys, such that a user may mutually exclusively select between said primary key and said secondary key;
wherein each of said primary and secondary keys is individually actuabie.

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45. The cluster keyboard as claimed in claim 44, comprising at least one
additional cluster key, wherein the cluster keys are located adjacent each other so
as to form a row,
46. The cluster keyboard as claimed in claim 44, comprising at least two
additiona! cluster keys, wherein the primary keys of the cluster keys are located
adjacent each other so as to form a row.
47. The cluster keyboard as claimed in claim 44, wherein said primary key and
said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user.
48. A method of inputting data using a keyboard in which more than one key is
located within the width of a fingertip, comprising the steps of:
providing a cluster keyboard comprising a first cluster key and a second cluster key, each said cluster key comprising at least two keys:
one of said keys of each cluster key being a primary key; at least one of said keys of each cluster key being a secondary key, said secondary keys being located immediately adjacent and circurnferentially to said primary key of said cluster key;
receiving input signals from two of said keys, said input signals being received close in time to each other; and
processing said input signals in accordance with a predetermined set of logical rules such that the cluster keyboard recognizes said input signal from only one of said keys;
wherein said set of logical rules includes a plurality of sensory thresholds;
at least one of said sensory thresholds is a threshold for actuation;
wherein when both said primary key and said secondary key have met said threshold for actuation close in time to eaeh other, said set of logical rules utilizes an order of activation and at least one difference between said primary and said secondary key other than the order of activation to select between said primary and said secondary key.

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49. A method of inputting data as claimed in claim 48, wherein said set of
logical rules uses differences in pressure to select one of said keys,
50. A method of inputting data as claimed in claim 48, wherein said set of
logical rules uses differences in shadowing to select one of said keys.
51. A method of inputting data using a keyboard in which more than one key is
located within the width of a fingertip, comprising the steps of:
providing a cluster keyboard comprising a first cluster key and a second cluster key, each said cluster key comprising at least two keys:
one of said keys of each said cluster key being a single primary key, said primary key having a support structure that supports the primary key;
at least one of said keys of each cluster key being a secondary key, said secondary key being located adjacent and circumferentially to said primary key of said cluster key, said secondary key having a support structure that supports the secondary key;
actuating two of said keys, said two of said keys being actuated close in time to each other, thereby actuating a mutual exclusivity actuator;
said mutual exclusivity actuator interacting with said support structure of said two actuated keys, said mutual exclusivity actuator acting to exclude input from one of said two actuated keys.
52. A cluster key arrangement as claimed in claim 1, wherein each of said
primary key and said secondary key has an associated electrical contact,
activation of each said electrical contact sends a signal which indicates an input
from said cluster key arrangement, and said mutual exclusivity selecting means
selects between said primary key and said secondary key during preprocessing.
53. A cluster key arrangement comprising at least one cluster key, said cluster
key comprising:

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a single primary key;
at least one secondary key, said secondary key being located immediately adjacent to said primary key of said cluster key; and
mutual exclusivity selecting means for selecting said primary key or said secondary key in a mutually exclusive manner;
wherein when both said primary key and said secondary key have met a threshold for actuation close in time to each other, said mutual exclusivity selecting means utilizes an order of activation and at least one difference between said primary key and said secondary key other than the order of activation to select between said primary and said secondary key;
each of said primary key and said secondary key upon actuation move in a direction substantially parallel to the motion of the other of said primary and said secondary key upon actuation;
each of said primary key and said secondary key has an associated elastomeric shell cap, activation of each said elastomeric shell cap sends a signal which indicates an input from said cluster key arrangement, and said mutual exclusivity selecting means selects between said primary key and said secondary key during preprocessing,
54. A method of inputting data, said method comprising the steps of:
providing a keyboard in which more than one key is located within the width of a fingertip, said-keyboard comprising a first cluster key and a second cluster key;
each said cluster key comprising at least two keys;
one of said keys of each said cluster key being a primary key;
at least one of said keys of each cluster key being a secondary key, said secondary keys being located immediately adjacent and drcumferenttally to said primary key of said cluster key;
receiving input signals from at least two of said keys, said input signals being received close in time to each other; and

61
processing said input signals in accordance with a predetermined set of logical rules such that the cluster keyboard recognizes the input signal from only one of the two keys;
wherein said logical rules require detection and recognition of the signal source key of the first arriving signal;
and said logical rules require that no signal arriving after the first signal arrival shall be processed until all signals from the keys have first been removed.
55. The method as claimed in claim 54, wherein said at least two keys are
from the same cluster key of said cluster keys.
56. The method as ciaimed in claim 54, wherein said at least two keys are
from different cluster keys of said cluster keys.
57. A method for receiving input, said method comprising the steps of:
providing a keyboard located on a portable handheld device, said keyboard
having a plurality of keys, each of said keys being spaced on the keyboard such that more than one key is located within a width of a fingertip;
receiving for preprocessing a first input from a primary key, said primary key being pressingly actuated by a fingertip;
receiving for preprocessing at least one additional input from a secondary key, the secondary, key being actuated during the actuation of the primary key as a result of the secondary key being located within the width of the fingertip that actuated the primary, key;
processing the first input and the.at least one additional input using a set of logic rules to mutually exclusively recognize only the first input;
wherein said set of logic rules utilizes an order of activation and at least one difference between said primary key and said secondary key other than the order of activation to select between said primary key and said secondary key.

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58. A cluster keyboard comprising:
a support structure;
at feast one cluster key, said support structure supporting said cluster key; said cluster key comprising:
at feast one primary key;
at least one secondary key, said secondary key being located immediately adjacent to said primary key of said cluster key;
said primary key and said secondary key being attached separately to said support structure, so that each of said primary key and said secondary key is Individually actuable;
a mutual exclusivity selecting means, said mutual exclusivity selecting means including a configuration selected from the group consisting of a mechanical configuration, an electronic configuration, and an opto-electronic configuration, said mutual exclusivity selecting means being configured to use input from a user to mutually exclusively select between said primary key and said secondary key.
59. A cluster keyboard as claimed in claim 58, wherein said secondary key is
smaller in surface area than said primary key.
60. A cluster keyboard as claimed in claim 58, wherein each of said primary
key and said at least one secondary key has a width, and the width of said at *
least one secondary key is less than about 50% of the width of said primary key.
61. A cluster keyboard as claimed in claim 60, wherein the width of said at
least one secondary key is about 40% of the width of said primary key.
62. The duster keyboard as claimed in claim 58, wherein the mutual exclusivity
selecting means comprises a mechanical configuration wherein the primary key
and secondary key mechanically interact with each other such that when one is
actuated the other is prevented from being actuated.

63
63. The cluster keyboard as claimed in claim 58, comprising at least one
additional cluster key, wherein the cluster keys are located adjacent each other so
as to form a row.
64. The cluster keyboard as claimed in claim 58, comprising at least two
additional cluster keys, wherein the primary keys of the cluster keys are located
adjacent each other so as to form a row.
65. The cluster keyboard as claimed in claim 58, wherein said primary key and
said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user.
66. A method for receiving input from a keyboard located on a portable
handheld device, said keyboard having a plurality of keys, each of which keys is
spaced on the keyboard such that more than one key is located within a width of
a fingertip, said method comprising the steps of:
receiving for preprocessing a first input from a first key of the plurality of keys, said first key being pressingly actuated by a fingertip ;
receiving for preprocessing a second input from a second key of the plurality of keys, said second key being pressingly actuated by the fingertip, said second input being received close in a threshold close in time to the receipt of the* first input;
processing the first input and the second input using a set of logic rules to determine that the second key is within a width of a fingertip of the first key ,
recognizing the first input mutually exclusive of the second input.
67. The method.as claimed in claim 66 wherein the time threshold is set to be
a duration of time sufficiently short to ensure that the second key is more likely
than not to have been actuated by the same pressing of the fingertip that
actuated the first key.

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68. A method for receiving input from a keyboard located on a portable
handheld device, said keyboard having a plurality of keys, each of which keys is
spaced on the keyboard such that more than two keys are located within a width
of a fingertip, said method comprising the steps of:
generating a first output from a first key of the plurality of keys, said output being actuated by the pressing of a fingertip on the first key ;
generating a second output from a second key of the plurality of keys, said output being actuated by the pressing of the fingertip on the second key;
processing the first input and the second input using a set of logic rules to determine that the second key is within a width of a fingertip of the first key and that the second input was generated close in time to the generation of the first input;
recognizing the actuation of the first key mutually exclusive of the second key.
69. The method as claimed in claim 68, comprising :
generating a third output from a third key of the plurality of keys, said output being actuated by the pressing of a different fingertip than that which actuates the first key; and
recognizing the actuation of the third key.
70. A method for receiving input from a keyboard located on a portable
handheld device, said keyboard having a plurality of keys, each of which keys is
spaced on the keyboard such that more than one key is located within a width of
a fingertip, said method comprising the steps of:
accepting a first input from a first key of the plurality of keys, said first key being pressingly actuated ;
using a set of logic rules to determine that a second input is generated by an actuation of a second key that is located within a threshold distance of the first key and that the second key was actuated within a time threshold of the first key being actuated ; and

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rejecting the second input from the second key.
71. The method as claimed in claim 70, comprising :
using a set of logic rules to determine that a third input is generated by an actuation of a third key that is located outside a threshold distance of the first key; and
accepting the third input from the third key.
72. The method as claimed in claim 71, wherein the threshold distance is
about the width of a fingertip.
73. A keyboard for use by a user, said keyboard comprising :
a primary key;
at ieast three secondary keys circumferentialiy spaced about the primary key;
each of said primary key and said secondary keys being spaced such that a user who actuates the primary key with a fingertip also actuates two or more secondary keys within a time threshold of actuating the primary key ;
a processor to detect the actuation of the primary key and the secondary keys, said processor having a logic set to identify the primary key and to disregard' the actuation of the two or more of the secondary keys when said two or more secondary keys are actuated within a time threshold of the actuation of the primary key,
74. A method of inputting data using a keyboard in which more than one key is
located within the width of a fingertip, comprising a first cluster key and a second
cluster key, each said cluster key comprising at least two keys :
one of said keys of each cluster key being a primary key ;
at least one of said keys of each cluster key being a secondary key, said secondary keys being located immediately adjacent and' circumferentially to said primary key of said cluster key ;

66
receiving input signals from at feast two of said keys, said input signals being received close in time to each other; and
processing said input signals in accordance with a predetermined set of logical rules such that the cluster keyboard recognizes the input signal from only one of the two keys;
wherein said logical rules require detection and recognition of the signal source key of the first arriving signal and said logical rules require that no signal arriving after the first signal arrival shall be detected until all signals from the keys have first been removed.
75. The method as claimed in claim 74, wherein the said at least two keys are from the same cluster.
78. The method as claimed in claim 74, wherein the said at least two keys are from the different clusters.
77. A cluster key for operation by a fingertip, said cluster key comprising ;
a case, said case having a generally planar surface, said case having a through-hole formed therethrough ;
one primary key, said primary key moving perpendicular to said planar surface of said case in response to the pressure applied by the fingertip in pushbutton tike fashion, said primary key having sn underside and a center section ;
an electrical contact located on said underside of said primary key ;
one secondary key, said secondary key being located immediately adjacent to said primary key, said secondary key protruding through said through-hole in said case;
said secondary key rotating in response to the pressure applied by the fingertip, said secondary key having at (east one secondary key section, said at least one secondary key section having an underside, a center end and a peripheral end;

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said center end of said at least one secondary key section being formed as a surface adjacent said primary key ;
an electrical contact located on said underside of said at feast one secondary key section;
an insulating board, said insulating board having at ieast two switch contacts formed thereon, one of said at ieast two switch contacts being located beneath said primary key, and one of said at least two switch contacts being located beneath said at ieast one secondary key section, so that on activation the switch contacts make contact with the electrical contacts located on the underside of the primary key and the at ieast one secondary key section respectively, each switch contact closing a switch ;
said center section of said primary key and said surface of said at least one secondary key section adjacent said primary key being dimensioned and configured so that when said at least one secondary key section rotates in response to pressure applied by the fingertip, said surface of said secondary key adjacent said primary key interacts with said center section, so that activation of either said primary key or said secondary key section excludes activation of the other of said primary key and said secondary key section.
78. A cluster key as claimed in claim 77, wherein said surface of said at least
one secondary key section adjacent said primary key is a stepped surface.
79. A cluster key as claimed in claim 77; wherein:
each of said primary key and said at least one secondary key section has
an upper surface; \ ¦*, /
said upper surface of said primary key has a convex shape; and
said upper surface orsaidwat least one secondary key section has a
concave shape.
80. The cluster key as claimed in claim 77, wherein said primary key and said
secondary key are constructed from material having a large range of hardness to
provide positive tactile feedback to a user.

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81. A cluster key as claimed in claim 77, wherein said at least one secondary
key section is arranged at an outer circumference of said primary key.
82. A cluster key as claimed in claim 77, wherein said secondary key
comprises at least four secondary key sections.
83. A duster keyboard comprising:
at least one cluster key, said cluster key comprising:
a primary key, said primary key having a keytop area and an underside;
at least one secondary key, said secondary key having a keytop area and an underside;
said primary key being located adjacent to said secondary key;
said keytop areas of said primary key and said at feast one secondary key differing in tactile feel from one another;
said primary key and said at least one secondary key differing in shape from one another;
a flexible substrate;
a circuit board, said flexible substrate being located between said undersides of said primary and secondary keys and said circuit board;
at least two snap domes;
each snap dome having an associated electrical contact, each snap dome being aligned with the underside of one of said primary and said secondary keys;
said primary and said secondary keys and said snap domes generating positive tactile feedback to a user of said cluster keyboard;
a set of predetermined logical rules, said set of predetermined logical rules selecting between said primary and said secondary keys in a mutually exclusive manner according to signals generated by said electrical contacts.
84. A cluster keyboard as claimed in claim 83, wherein said secondary key is
smaller in surface area than said primary key.

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85. The cluster keyboard as claimed in claim 83, wherein said primary key and
said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user.
86. A cluster keyboard as claimed in claim 83, wherein each of said primary
key and said at least one secondary key has a width, and the width of said at
least one secondary key is less than about 50% of the width of said primary key.
87. A cluster keyboard as claimed in claim 88, wherein the width of said at
least one secondary key is about 40% of the width of said primary key.
88. A method of inputting data, said method comprising the steps of:
providing a keyboard, said keyboard comprising at least two keys, said two
keys being spaced on the keyboard such that more than one key is located within the width of a fingertip;
. receiving input signals from said at least two keys, said input signals being received close in time to each other; and
processing said input signals in accordance with a predetermined set of logical rules such that the keyboard recognizes the input signal from only one of the two keys;
wherein said logical rules require detection and recognition of the signal source key of the first arriving signal;
and said logical rules require that no signal arriving after the first signal arrival shall be processed until all signals from the two keys have first been removed.
89. A method for receiving input, said method comprising the steps of:
providing a keyboard located on a portable handheld device, said keyboard
having a plurality of keys, each of said keys being spaced on the keyboard such that more than one key is located within a width of a fingertip;

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receiving for preprocessing a first input from a primary key, said primary key being pressing^ actuated by a fingertip;
receiving for preprocessing at least one additional input from a secondary key, the secondary key being actuated during the actuation of the primary key as a result of the secondary key being located within the width of the fingertip that actuated the primary key;
processing the first input and the at least one additional input using a set of logic rules to mutually exclusively recognize only the first input
90, A cluster keyboard comprising:
at least one cluster key, said cluster key comprising:
a primary key, said primary key having a keytop area and an underside;
at least one secondary key, said secondary key having a keytop area and an underside;
said primary key being located adjacent to said secondary key;
said keytop areas of said primary key and said at least one secondary key^ differing in tactile feel from one another;
said primary key and said at least one secondary key differing in shape from one another;
a flexible substrate;
a circuit board, said flexible substrate being located between said undersides of said primary and secondary keys and said circuit board;
a first snap dome, said first snap dome being aligned with the underside of said primary key;
a second snap dome, said second snap dome being aligned with the underside of said at least one secondary key;
said primary and said secondary keys and each of said snap domes generating positive tactile feedback to a user of said cluster keyboard;
each of said primary key and said at least one secondary key generating an electrical signal upon actuation;
a set of predetermined logical rules, said set of predetermined logical rules

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selecting between said primary and said secondary keys in a mutually exclusive manner according to the electrical signals generated by said primary key and said at least one secondary key.
91. A duster keyboard as claimed in claim 90, wherein each of said primary
key and said at least one secondary key has a width, and the width of said at
least one secondary key fs less than about 50% of the width of said primary key.
92. A cluster keyboard as claimed in claim 91, wherein the width of said at
least one secondary key is about 40% of the width of said primary key.
93. The ciuster keyboard as claimed in claim 90, wherein said primary key and
said secondary key are constructed from material having a large range of
hardness to provide positive tactile feedback to a user,
94. A clyster keyboard as claimed in ciaim 90, wherein said secondary key is
smaller in surface area than said primary key.
A cluster key arrangment may be
mechanically configured or eletronically
configured, The cluster kay arrangment may
include twelve cluster keys configured in an
arrangement of three columns by four rows,
such as conventionally found on standard
telephones. The cluster key arrangement may
also be eonfigured for user on cellular/mobile
telephones, television remote controls, other
handheld, data entry devices, automotive
controls. desktop/will-mounted/coedless
telephones, combination telephone recorders, Personal Digttal Assistants, and other electronic devices. The mechanically or electronically configured cluster keys provide
a user with the abiliiy to select one of
a plurality of key elements representing
numbers, letters, symbols, function, etc. in
a manually exclusives manner.

Documents:


Patent Number 203827
Indian Patent Application Number IN/PCT/2001/01228/KOL
PG Journal Number 11/2007
Publication Date 16-Mar-2007
Grant Date 16-Mar-2007
Date of Filing 22-Nov-2001
Name of Patentee KRISHNAN RAVI C
Applicant Address 10112 PARKWOOD TERRACE, BETHESDA,MD 20814
Inventors:
# Inventor's Name Inventor's Address
1 KRISHNAN RAVI C 10112 PARKWOOD TERRACE, BETHESDA,MD 20814
PCT International Classification Number G06F H04M1/00
PCT International Application Number PCT/US00/10545
PCT International Filing date 2000-04-20
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/296,809 1999-04-23 U.S.A.