Title of Invention

DEVICE, SYSTEM AND METHOD FOR COLOR DISPLAY

Abstract

A color Liquid Crystal display (LCD) device for displaying a color image using at least four different primary colors, the device including an array of Liquid Crystal (LC) elements, driving circuitry adapted to receive an input corresponding to the color image and to selectively activate the LC elements of the LC array to produce an attenuation pattern corresponding to a gray-level representation of the color image, and an array of color sub-pixel filter elements juxtaposed and in registry with the array of LC elements such that each color sub-pixel filter element is in registry with one of the LC elements, wherein the array of color sub-pixel filter elements comprises at least four types of color sub-pixel filter elements, which transmit light of the at least four primary colors, respectively.

Full Text

DEVICE. SYSTEM AND METHOD FOR COLOR DISPLAY Field Of The Invention The invention relates generally to color display devices, systems and methods and, more particularly, to display devices, systems and methods having improved color image reproduction capability. increasing steadily. A typical color LCD device is schematically illustrated in Fig. 2A. Such a device includes a light source 202, an array of liquid crystal (LC) elements (cells) Otlier than controlling the geometric arrangement of pixels, the '375 patent does not describe or suggest any visual interaction between the three primary colors and the fourth color in the repetitive sequences. LCDs are used in various applications. LCDs are particularly common in portable devices, for example, the small size displays of PDA devices, game consoles and mobile telephones, and the medium size displays of laptop ("notebook") computers. These applications require than and miniaturized designs and low power consumption. However, LCD technology is also used in non-portable devices, generally requiring larger display sizes, for example, desktop computer displays and TV sets. Different LCD applications may require different LCD designs to achieve optimal results. The more "traditional" markets for LCD devices, e.g., the markets of battery-operated devices (e.g., PDA, cellular phones and laptop computers) require LCDs with high brightness efficiency, which leads to reduced power consumption. In desktop computer displays, high resolution, image quality and color richness are the primary considerations, and low power consumption is only a secondary consideration. Laptop computer displays require both high resolution and low power consumption; however, picture quality and color richness are compromised in many such devices. In TV display applications, picture quality and color richness are generally the most important considerations; power consumption and high resolution are secondary considerations in such devices. Typically, the light source providing back-illumination to LCD devices is a Cold Cathode Fluorescent Light (CCFL). Fig. 3 schematically illustrates typical spectra of a CCFL, as is known in the art. As illustrated in Fig. 3, the light source spectra include three, relatively narrow, dominant wavelength ranges, corresponding to red, green and blue light, respectively. Other suitable light sources, as are known in the art, may alternatively, be used. The RGB filters in the filter sub-pixel array are typically designed to reproduce a sufficiently wide color gamut (e.g., as close as possible to the color gamut of a corresponding CRT monitor), but also to maximize the display efficiency, e.g., by selecting filters whose transmission curves generally overlap the CCFL spectra peaks in Fig. 3. In general, for a given source brightness, filters with narrower transmission spectra provide a wider color gamut but a reduced display brightness, and vice versa. For example, in applications where power efficiency is a critical consideration, color gamut width may often be sacrificed. In certain TV applications, brightness is an inipoitant consideration; however, dull colors are not acceptable. Fig. 4A schematically illustrates typical RGB filter spectra of existing laptop computer displays. Fig. 4B schematically illustrates a chromaticity diagram representing the reproducible color gamut of the typical laptop spectra (dashed-triangular area in Fig. 4B), as compared with an ideal NTSC color gamut (dotted triangular area in Fig. 4B). As shown in Fig, 4B, the NTSC color gamut is significantly wider than the color gamut of the typical laptop computer display and therefore, many color combinations included in the NTSC gamut are not reproducible by the typical color laptop computer display. Summary Of The Invention Many colors seen by humans are not discernible on standard red-green-blue (RGB) monitors. By using a display device with more than three primary colors, the reproducible color gamut of the display is expanded. Additionally or alternatively, the brightness level produced by the display may be significantly increased. Embodiments of the present invention provide systems and methods of displaying color images on a display device, for example, a thin profile display device, such as a liquid crystal display (LCD) device, using more than three primary colors. An aspect of the invention provides improved multi-primary display devices using more than three sub-pixels of different colors to create each pixel. In embodiments of this .aspect of the invention, the use of four to six (or more) different color sub-pixels, per pixel, allows for a wider color gamut and higher luminous efficiency. In some embodiments, the number of sub-pixels per pixel and the color spectra of the different sub-pixels may be optimized to obtain a desired combination of a sufficiently wide color gamut, sufficiently high brightness, and sufficiently high contrast. - In some embodiments of the invention, the use of more than three primary colors may expand the reproducible color gamut of the display by enabling the use of relatively narrow wavelength ranges for some of the primary colors, e,g,, red, green and blue, thus increasing the saturation of those primary colors. To compensate for a potentially reduced brightness level from such narrower ranges, in some embodiments of the invention, broad wavelength range primary colors, e.g., specifically designed yellow and/or cyan, may be used in addition to the narrow wavelength range colors, thus increasing the overall brightness of the display. In further embodiments of the invention, additional primary colors (e.g., magenta) and/or different primary color spectra may be In accordance with embodiments of an aspect of the invention, there is thus provided a color Liquid Crystal Display (LCD) device for displaying a color image using at least four different primary colors, the device including an array of Liquid Crystal (LC) elements, driving circuitry adapted to receive an input corresponding to the color image and to selectively activate the LC elements of the LC an-ay to produce an attenuation pattern corresponding to a gray-level representation of the color image, and an an-ay of color sub-pixel filter elements juxtaposed and in registry with the array of LC elements such that each color sub-pixel filter element is in registy with one of the LC elements, wherein the array of color sub-pixel filter elements includes at least four types of color sub-pixel filter elements, which transmit light of the at least four primary colors, respectively. In accordance with embodiments of another aspect of the invention, there is provided a color Liquid Crystal Display (LCD) device for displaying a temporally-integrated color image including a sequence of at least four primary color hnages, the device including an array of Liquid Crystal (LC) elements, driving circuitry adapted to receive an input corresponding to each of the at least four primary color images and to selectively activate the LC elements of the LC anay to produce an attenuation pattern corresponding to a gray-level representation of each of the at least four primary color images, respectively, and an illumination system adapted to sequentially back-illuminate the LC anay with light of at least four different primary colors to sequentially produce the at least four, respective, primary color images, wherein the driving circuitry and the illumination system are synchronized such that each the attenuation pattern is illuminated with light of the primary color corresponding to the respective primary color image. In some embodiments of this aspect of the invention, the illimiination system includes a light source having an output path, a filter switching mechanism which sequentially interposes at least four different primary color filters in the output path of the light source to produce the light of at least four different primary colors, respectively, and an optical arrangement which guides the light of at least four different primary colors from the filter switching mechanism to the LC array thereby to back-illuminate the LC an-ay. In other embodiments of this aspect of the invention, the illumination system includes an an-ay of Light Emitting Diodes (LEDs), illumination control circuitry adapted to selectively activate the plurality of LEDs to produce a sequence of at least four illumination patterns corresponding to tlae hght of at least four different primary colors, respectively, and an optical arrangement which causes the at least four illumination patterns produced by the array of LEDs to back-illuminate the LC array with a generally spatially homogeneous light of the at least four, respective, primary colors. In accordance with embodiments of a further aspect of the invention, there is provided a color display device for displaying an n-primary image, wherein n is greater than three, having an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors arranged in an array of periodically repetitive super-pixel structui-es covering substantially the entire n-primary image, each super-pixel structure including a predetermined, fixed, number of n-primary pixels, each n-primary pixel including one color sub-pixel element of each of the at least four different primary colors, wherein no fixed combination of n-primary pixels covering only part of the super-pixel structure can be periodically repeated to cover substantially the entire n-primary image. In some embodiments of this aspect of the invention, the at least four primary colors include at least five prirmary colors, and the super pixel structure includes a substantially rectangular arrangement including five sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of the five primary colors. In other embodiments of this aspect of the invention, the at least four primary colors include at least six primary colors, and the super pixel structure includes a substantially rectangular arrangement including three sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of the six primary colors. In accordance with embodiments of an additional aspect of the invention, there is provided a method of displaying an n-primary color image, wherein n is greater than three, on an n-primary color display having an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors arranged in an array of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure including a predetermined, fixed, number of n-primary pixels, each n-primary pixel including one color sub-pixel element of each of the at least four different primary colors, wherein no fixed combination of n-primary pixels covering only part of the super-pixel structure can be periodically repeated to cover substantially the entire n-primary image, the method including receivmg an input representing three-component color image data, e.g., RGB or YCC data, including a plurality of three-component pixels and having a first resolution, scaling the three-component color image data to produce scaled three-component color image data having a second resolution different fr-om the first resolution, converting the scaled three-component color image data into corresponding n-primary color pixel data representing the n-primary color image, and generating an n-primary input signal con'esponding to the n-primary color pixel data. In some embodiments of this aspect of the invention, the method includes, before generating the n-primary input signal, collecting the n-primary color pixel data of all n-primary pixels of each super-pixel, and distributing the collected data representing each super-pixel stucture into a plurality of sub-pixel data segments, each segment representmg one sub-pixel of each the super-pixel, wherem generating the n-primary input signal includes generatmg a gray-level value for each of the sub-pixels. In accordance with embodiments of yet another aspect of the invention, there is provided a method of displaymg an n-primary image, wherein n is greater than or equal to six, on an n-primary display having an array of color sub-pixel elements including color sub-pixel elements of each of at least six different primary colors, including at least a first set of primary colors and a second set of primary colors, arranged in a periodically repeating arrangement including at least one color sub-pixel element of each of the at least six different primary colors, the method including receiving an image input representing unage data including a plurality of pixels, each pixel including one sub-pixel of each of the first set of primary colors, separating the unage data into a first image component, including a first group of the pixels, and a second image component, including a second group of the pixels, wherein each pixel in the first group is substantially adjacent to a respective pixel in the second group, converting the pixels in the second group into corresponding, converted pixels, each pixel including one sub-pixel of each of the second set of primary colors, and generating an n-primary input signal representing data corresponding to each of the converted color pixels in the second group and the respective, substantially adjacent, pixel in the first group. In some embodiments of this aspect of the invention, the method includes, before generating the n-primary input signal, combining each of the converted pixels in the second group with the respective, substantially adjacent, pixel of the first group, to produce a corresponding n-primary pixel including one sub-pixel of each of the at least six primary colors, wherein generatmg the n-primary mput signal includes generating a signal representing data coiTesponding to each the n-primary pixel. Further, in some embodiments of this aspect of the invention, the image input includes a color image input representing three-component color image data, e.g., RGB or YCC data, wherein the at least first and second sets of primary colors include first and second sets of three primary colors, and wherein each color pixel of the n-primary image is reproduced by either the first or second set of three primary colors. In other embodiments of this aspect of the invention, the image input mcludes a black-and-white image mput representing black-and-white image data including a plurality' of black-and-white pixels. The at least first and second sets of primary colors may include first and second sets of three, complementary, primary colors, and each black-and-white pixel of the n-primary image may be produced by either the first or second set of primary colors. Alternatively, the at least first and second sets of primary colors include first, second and third pairs of complementary piimary colors, and each black-and-white pixel of the n-primary image is produced by one of the first, second and third pairs of primaiy colors. In accordance with embodiments of a still further aspect of the invention, there is provided a color display device for displaying an n-primary image, wherein n is greater than or equal to six, having an array of color sub-pixel elements including color sub-pixel, elements of each of at least six different primary colors, including at least a first set of primary colors and a second set of primary colors, arranged in a periodically repeating arrangement including at least one color sub-pixel element of each of the at least six different primary colors, wherein each sub-pixel in the periodically repeating arrangement is adjacent at least one sub-pixel of a complementary primary color. In some embodiments of this aspect of the invention, the periodically repeating arrangement includes a first sequence of sub-pixel elements of each of the first set of primaiy colors and a second sequence of sub-pixel elements of each of the second set of primary colors, wherein each sub-pixel element in the first sequence is adjacent a sub-pixel element of a complementary primary color in the second sequence. In accordance with embodiments of yet an additional aspect of the invention, tiiere is provided a system for displaying an n-primary color image, wherein n is gi'eater than three, including an n-primary color display device havmg an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colorsarranged in anarray of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure including a predetermined, fixed, number of n-primary pixels, each n-primary pixel including one color sub-pixel element of each of the at least four different primary colors, wherein no fixed combination of n-primary pixels covering only part of the super-pixel structure can be periodically repeated to cover substantially the entire n-primary image, means for receiving an input representing three-component color image data, e.g., RGB or YCC data, including a plurality of three-component pixels and having a first resolution, a scaling unit, which scales the three-component color image data to produce scaled three-component color image data having a second resolution different from the first resolution, a converter which converts the scaled three-component color image data into corresponding n-primary color pixel data representing the n-primary color image, and means for generating an n-primary input signal corresponding to the n-primary color pixel data. In some embodiments of this aspect of the invention, the system further includes a collection unit, which collects the n-primary color pixel data of all n-primary pixels of each super-pixel, and a distribution unit, which distributes the collected data representing each super-pixel structure into a plurality of sub-pixel data segments, each segment representing one sub-pixel of each the super-pixel, wherein the means for generating the n-primary input signal generates a gray-level value for each of the sub-pixels. In accordance with embodiments of still another aspect of the invention, there is provided a system for displaying an n-primary image, wherein n is greater than or equal to six, including an n-primary display device having an array of color sub-pixel elements including color sub-pixel elements of each of at least six different primary colors, including at least a fust set of primary colors and a second set of primary colors, arranged in a periodically repeating arrangement including at least one color sub-pixel ' element of each of the at least six different primary colors, an image collector which receives an image input representing image data including a plurality of pixels, each pixel includmg one sub-pixel of each of the first set of primary colors, means for separating the color image data into a first image component, including a first group of the pixels, and a second image component, mcluding a second group of the pixels, wherein each pixel in the first group is substantially adjacent to a respective pixel in the second group, means for converting the pixels in the second group mto corresponding, converted pixels, each pixel including one sub-pixel of each of the second set of primary colors, and means for generating an n-primary input signal representing data correspondmg to each of the converted color pixels in the second group and the respective, substantially adjacent, pixel in the first group. hi some embodiments of this aspect of the invention, the system further includes a pixel combiner which combines each of the converted color pixels in the second group with the respective, substantially adjacent, pixel of the first group, to produce a corresponding n-primary pixel including one sub-pixel of each of the at least six primary colors, wherein the means for generating the n-primary input signal generates a signal representing data corresponding to each the n-primary pixel. In embodiments of the present mvention, the wavelength ranges of the at least four primary colors or, in some embodiments, the at least five or six primary colors, are selected to provide an optimal over-all brightness of the displayed images. Additionally or alternatively, the wavelength ranges of the at least four primary colors are selected to provide an optimal color gamut width of the displayed images. In accordance with embodiments of yet another aspect of the invention, thrjre is provided a color display device for displaying an n-primary image, wherein n is greater than thi'ee, having an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors aiTanged in an array of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure including a predetemiined, fixed, number of n-primary pixels, each n-primary pixel including one color sub-pixel element of each of the at least foui" different primary colors, wherein the sub-pixel elements in each super-pixel structure are arranged in a rectangular sub-array having an average aspect ratio sufficiently close to one. Brief Description Of The Drawings The invention will be understood and appreciated more fully from the following detailed description of embodiments of the invention, taken in conjunction with the accompanying drawings in which: Fig. 1A is a schematic illustration of a chromaticity diagram representing a prior art RGB color gamut, superimposed with a chromaticity diagram of the color gamut of a human vision system, as is known in the art; Fig. IB is a schematic illustration of a chromaticity diagram representing a wide color gamut in accordance with an exemplary embodiment of the invention, superimposed with the chromaticity diagram of Fig. 1 A; Fig. 2A is a schematic block diagram illustrating a prior art 3-primary LCD system; Fig. 2B is a schematic block diagram illustratmg an n-primary LCD system in accordance with an embodiment of the invention; Fig. 3 is a schematic graph illustrating typical spectra of a prior art Cold Cathode Fluorescent Light (CCFL) source; Fig. 4A is a schematic graph illustrating typical RGB filter spectra of a prior art laptop computer display; Fig. 4B is a schematic illustration of a chromaticity diagram representing the color gamut reproduced by the prior art RGB filter spectra of Fig. 4A, superimposed with an ideal prior art NTSC color gamut; Fig. 5A is a schematic graph illustrating transmission curves of one, exemplary, filter design for a five-primary display device in accordance with an embodiment of the invention; Fig. 5B is schematic illustration of a chromaticity diagi'am representing the color gamut of the filter design of Fig. 5A, superimposed with two exemplaiy prior art color gamut representations; Fig. 6A is a schematic graph illustrating transmission curves of another, exemplary, filter design for a five-primary display device in accordance with an embodiment of the mvention; Fig. 6B is schematic illustration of a chromaticity diagram representing the color gamut of the filter design of Fig. 6A, superimposed with two exemplary prior art color gamut representations; Fig. 7A is a schematic graph illustrating transmission curves of a filter design for a six-primary display device in accordance with an embodiment of the invention; Fig. 7B is schematic illustration of a chromaticity diagram representmg the color gamut of the filter design of Fig. 7A, superimposed with two exemplary prior ait color gamut representations; Fig. 8 is a schematic illustration of an exemplary arrangement of sub-pixels in a four-primary display device according to embodiments of the invention; Fig. 9 is a schematic illustration of an exemplary arrangement of sub-pixels, including a super-pixel structure, in a five-primary display device according to embodiments of the invention; Fig. 10 is a schematic illustration of an exemplary arrangement of sub-pixels, including a super-pixel structure, in a six-primary display device according to embodiments of the mvention; Fig. 11 is a schematic block diagram illustrating data flow in parts of an n-primary color display system in accordance with an embodiment of the invention; Fig. 12A is a schematic illustration depicting one exemplary pixelarrangement for a six-primary color display device in accordance with embodiments of the invention; Fig. 12B is a schematic illustration depicting another exemplary pixel an'angement for a six-primary color display device in accordance with embodiments of the invention; Fig. ]JA is a schematic illustration of an exemplary color gamut of a six-primary display in accordance with embodiments of the invention; Fig. 13B is schematic block diagram illustrating a data flow scheme for a six-primary color display system in accordance with an exemplary embodiment of the invention; Fig. 14 is a schematic illustration of a sequential n-primary color LCD device in accordance with an exemplary embodhnent of the invention; and Fig. 15 is a schematic illustration of a chromaticity diagram of a human vision color gamut divided into a plurality of color sub-gamut regions. Detailed Description Of Embodiments Of The Invention In the following description, various aspects of the invention are described, with reference to specific embodmients that provide a thorough understanding of the invention; however, it will be apparent to one sldlled in the art that the present invention is not limited to the specific embodiments and examples described herein. Further, to the extent that certain details of the devices, systems and methods described herein are related to known aspects of color display devices, systems and methods, such details may have been omitted or simplified for clarity. Fig. IB schematically illustrates a color gamut of a more-than-three-primary display in accordance with an embodiment of the invention, enclosed by a horseshoe diagram representing the perceivable color gamut of the human eye, on a chromaticity plane. The six-sided shape m Fig. IB represents the color gamut of a six-primary display in accordance with an exemplai7 embodiment of the invention. This color gamut is significantly wider than a typical RGB color gamut, which is represented by the dotted triangular shape in Fig. IB. Embodiments of monitors and display devices with more than three primaries, in accordance with exemplary embodiments of the invention, are described in U.S. Patent Application No. 09/710,895, entitled "Device, System And Method For Electronic True Color Display", filed November 14, 2000, in International Application PCT/ILO1/00527, filed June 7, 2001, entitled "Device, System and Method For Electronic True Color Display" and published December 13, 2001 as POT Publication WO 01/95544, in U.S. Patent Application No. 10/017,546, filed December 18, 2001, entitled "Spectrally Matched Digital Print Proofer", and in International Application PCT/IL02/00410, filed May 23, 2002, entitled "System and method of data conversion for wide gamut displays", thu disclosueres of all of which applications and publications are incorporated herein by reference. "While, in embodiments of the present invention, methods and systems disclosed in the above referenced patent applications may be used, for example, methods of converting source data to primary data, or methods of creating primary color materials or filters; in alternate embodiments, the system and method of the present invention may be used with any other suitable n-primary display technology, wherein n is greater than three. Certain embodiments described in these applications are based on rear or iront projection devices, CRT devices, or other types of display devices. While the following description focuses mainly on n-primaries flat panel display devices in accordance with exemplary embodiments of the invention, wherem n is greater than three, preferably using LCDs, it should be appreciated that, in alternate embodiments, the systems, methods and devices of the present invention may also be used in conjunction with other types of display and other types of light sources and modulation tecliniques. For example, it will be appreciated by persons skilled in the art that the principles of the n-primary color display device of the invention may be readily implemented, with appropriate changes, in CRT displays. Plasma display, Light Emitting Diode (LED) displays, Organic LED (OLED) displays and Field Emissions Display (FED) devices, or any hybrid combinations of such display devices, as are known in the art. Fig. 2B schematically illustrates a more-than-three prhnary color display system in accordance with an embodiment of the invention. The System includes a light source 212, an array of liquid crystal (LC) elements (cells) 214, for example, an LC array using thin Film Transistor (TFT) active-matrix technology, as is known m the art. the device further mcludes electronic circuits 220 for driving the LC array cells, e.g., by active-matrix addressing, as is known in the art, and an n-primary-color filter array 216, wherein n is greater than three, juxtaposed the LC array. In embodiments of the LCD devices according to embodiments of the invention, each full-color pixel of the displayed image is reproduced by more than three sub-pixels, each sub-pixel corresponding to a different primary color, e.g., each pixel is reproduced by driving a corresponding set of four or more sub-pixels. For each sub-pixel there is a corresponding cell in LC array 214. Back-illumination source 212 provides the light needed to produce the color images. The transmittance of each of the sub-pixels is controlled by the voltage applied to a corresponding LC cell of array 214, based on the image data input for the corresponding pixel. An n-primaries controller 218 receives the input data, e.g., in RGB or YCC format, optionally scales the data to a desired size and resolution, and adjusts the magnitude of the signal delivered to the different drivers based on the input data for each pixel. The intensity of white light provided by back-illumination source 212 is spatially modulated by elements of the LC array, selectively controlling the illumination of each sub-pixel according to the image data for the sub-pixel. the selectively attenuated light of each sub-pixel passes through a corresponding color filter of color filter array 216, thereby producing desired color sub-pixel combinations. The human vision system spatially integrates the light filtered through the different color sub-pixels to perceive a color image. The color gamut and other attributes of LCD devices m accordance with embodiments of the invention may be controlled by a number of parameters. these parameters mclude: the spectra of the back illumination element (light source), for example a Cold Cathode Fluorescent Light (CCFL); the spectal transmission of the LC cells in the LC array; and the spectral transmission of the color filters. In a 3-primaries display, the first two parameters, namely, the spectra of the light source and the spectral transmission of the LC cell, are typically dictated by system constraints and, therefore, the colors for the filters may be selected straightforwardly to provide the required colorimetric values at the "comers" of the desired RGB triangle, as shown in Fig. lA. To maximize the efficiency of 3-prnaries LCD devices, the spectral transmissions of the filters are designed to substantially overlap, to the extent possible, with the wavelength peaks of the light source. The filters selection in 3-primary LCD devices may be based primarily on maximizing the overall brightness efficiency. In this context, it should be noted that selectmg filters having narrower spectral transmission curves, which result in more saturated primary colors, generally decreases the over-all brightness level of the display. For a multi-primary display with more than three primary colors, in accordance with embodiments of the invention, an infinite number of filter combinations can be selected to substantially overlap a required color gamut. The filter selection method of the invention may mclude optmiizing the filter selection according to the following requirements: establishing sufficient coverage of a desired two-dimensional color gamut, for example, the NTSC standard gamut for wide-gamut applications and a "conventional" 3-color LCD gamut for higher brightness applications; maximizing the brightness level of a balanced white point that can be obtained from combining all the primary colors; and adjusting the relative intensities of the primary colors in accordance with a desired illumination standard, e.g., the D65 white point chromatzcity standard of High Definition TV (HDTV) systems. Embodiments of the present invention provide systems and methods of displaying color images on a display device, for example, a thin profile display device, such as a liquid crystal display (LCD) device, using more than three primary colors. A number of embodiments of the invention are described herein in the context of an LCD device with more than three primary colors; wherein the number of color filters used per pixel is greater than three. This arrangement has several advantages in comparison to conventional RGB display devices. First, the n-primary display device in accordance with the invention enables expansion of the color gamut covered by the display. Second, the device in accordance with the invention enables a significant increase in the luminous efficiency of the display; in some cases, an increase of about 50 percent or higher may be achieved, as discussed below. This feature of the invention is particularly advantageous for portable (e.g., battery-operated) display devices, because increased luminous efficiency extends the battery life and overall weight of such devices. third, a device in accordance with the invention enables improved graphics resolution by efficient utilization of a sub-pixel rendering technique of the present invention, as described in detail below with reference to specific embodiments of the invention. In some multi-primary display devices in accordance with embodunents of the invention, more than three sub-pixels of different colors are used to create each pixel. In embodiments of the invention, the use of four to six (or more) different color sub-pixels, per pixel, allows for a wider color gamut and higher luminous efficiency. In some embodiments, the number of sub-pixels per pixel and the transmittance spectrum of die different sub-pixel filters may be optimized to obtain a desired combination of a sufficiently wide color gamut, sufficiently high brightness, and sufficiently high contrast. For example, the use of more than three primaries in accordance with an embodiment of the invention may enable expansion of the reproducible color gamut by enabling, the use of filters with. nan-ower transmission curves (e.g., narrower effective transmission ranges) for the R, G and B color filters and, thus, increasing the saturation of the R, G and B sub-pixels. To compensate for such narrower ranges, m some embodiments of the invention, broader band sub-pixel filters may be used in addition to the RGB saturated colors, thus increasing the overall brightness of the display. In accordance with embodunents of the invention, an optimal combination of color gamut width and over-all picture brightness can be achieved, to meet the requirements of a given system, by appropriately designing the sub-pixel filters of the n-primary display and the filter arrangement. Figs! 5A and 6A schematically illustrate transmission curves for two, respective, alternative designs of a five-primary display device in accordance with embodiments of 3-color LCD. In this embodiment, the over-all brightness level of the 5-color LCD device is similar to that of a 3-color LCD device having a much nari'ower color gamut. The white point coordinates for this embodiment, as calculated from the transmission spectra and the back-illumination spectra using methods known in the known art, are x=0.310; y=0.343. Other designs may be used in embodiments of the invention, including tlie use of different primaiies and/or additional primaiies (e.g., 6 color preference to image brightness. The sub-gamut regions in Fig. 15 represent approximated boundaries from which primary colors may be selected to provide large gamut coverage and/or high brightness levels, while maintaining a desned white point balance, in accordance with embodiments of the invention. The positions of the primary To determine the smallest super-pixel structure that meets the above requirements, the number of n-primary pixels lengthwise or widthwise in each super-pixel is set to a value of one, for example, NL= I, whereby the aspect ratio of the multi-primary pixel is given by m2/3n. Therefore, the smallest super-pixel structure would be obtained for a value of m whereby m2 divided by 3n is as close as possible to a 5-primaries display system in accordance with an embodiment of the invention. In this 5-primaries configuration, wherein, for example, the primaries are RGB, cyan (C) and 2001. Optionally, following the up scaling, re-sampling may be performed in two stages, to simplify computation, as follows. In a first stage, data is allocated for each of the super-pixels. In a second stage, re-sampling is performed at the super-pixel level, based on the Icnown structure of the super-pixels. After the data is re-sampled to an n-primary pixel grid, which may be defined, for example, by the color-weighted centers of each of the n-primary pixels, a set of n-primary coefficients may be computed for each of the n-primary pixels by an n-primary converter 1104. The n-primary data for all, e.g., m, n-primary pixels making-up each of the super-pixels is combined by a super-pixel collector 1106, and the collected data is received by a distributor 1108, which distributes the in*n coefficients of the m n-primary pixels to the sub-pixels according to the defined internal arrangement. In a 6-primaries display system according to an embodiment of the invention, one possible configuration may include a super-pixel arrangement essentially analogous to the 5-primaries super-pixel arrangement described above with reference to Figs. 9, with appropriate changes, e.g., adding a magenta sub-pixel element to each pixel of the super-pixel structure. A system for producing 6-primary images in accordance with this embodiment, and the flow of data in such a system, may be substantially as described above with reference to Fig. 11. As illustrated schematically in Fig. 10, a super-pixel structure with n==6 and m=4 has a length 4/3 that of a 3-primary pixel, and a width of 3 pixels. The total number of sub-pixels in this super-pixel structure is thus 4/3x3x3 = 12, whereby two 6-primary pixels are accommodated by each super-pixel, as illustrated schematically by the shadowed area in Fig. 10. The average length of this 6-primary pixel is 4/3 and its width is 3/2 and thus the super-pixel aspect ratio in this embodiment is 8:9, which is relatively close to the desired 1:1 ratio. Other configurations may also be used in accordance with embodiments of the invention; for example, the six sub-pixels may be arranged in two rows of three sub-pixels each. In this two-row arrangement, the resolution of a standard XGA display adapted to operate in a six-primaries mode according to the invention is reduced 1024 x 384 pixels, and the resolution of a standard SXGA display operating m the 6-primaries mode is reduced to 1280 x 512. Such a configuration of pixels may be useful for TV and video applications as described below. The above examples demonstrate that an increase in the number of different color filters, e.g., 4-6 different colors instead of 3, without appropriate modification of the LC an-ay, may reduce the apparent resolution of the display. However, for TV and video applications this reduction in apparent resolution may not be crucial. Standard definition NTSC TV systems have a resolution of 480 lines (effectively 525 lines with blanldng lines) at an interlaced field rate of 60 Hz (frame rate of 30 Hz). When digitized, the resolution of NTSC systems varies within the range of 960 x 480 to 352 x 480. PAL systems have a resolution of 576 TV lies at an mterlaced field rate of 50 Hz (firame rate of 25 Hz). In digital form, the resolution of PAL systems varies within the range of 1024 X 576 to 480 X 576, depending on the aspect ratio (e.g., 4:3 or 16:9) and on the shape (e.g., rectangular or square) of the pixels. Therefore, in accordance with embodiments of the invention, existing SXGA displays can be converted into four-, five- or six-primaries display systems, as described above, that display standard definition TV images without any degradation in image resolution, because the reduced resolution of such converted devices is still higher than the resolution of standard TV image data. It should be noted that in all the cases described above, where the resolution is reduced horizontally, and in the case of five- and six-primaries where the resolution is reduced vertically, the resolution of converted display systems in accordance with embodiments of the invention are compatible with (or exceed) the resolution of NTSC systems (480 lines) and are at least very close to the resolution of PAL systems (576 lines). In certain cases where an XGA display is converted to operate as a 4-6 primary display', some resolution may be lost; however, a sophisticated arrangement of the sub-pixels within each pixel, as described below, can be used to compensate for the slightly decreased resolution. Thus will be apparent to a person skilled in the art that many existing types of 3-color LCD devices can be converted into more-than-three-primary displays, according to embodiments of the invention, capable of displaying TV standard images with no effective reduction in resolution. Other resolutions, number of primaries and pixel arrangements may be used in accordance with embodiments of the invention. In various applications, especially in mixed video and computer graphics applications, any loss of resolution should preferably be avoided. For pixels with six sub-pixelsarranged in two rows, as described above, special arrangement of the different sub-pixel colors can be implemented to improve the display resolution. An example of and the gamut of the CMY primaries spans the solid triangle. The shadowed hexagonal area in Fig. 13A represents the conjunctive gamut of both the CMY and RGB primary sets. A first mode of operation of this display is a high resolution, "limited gamuf mode, which is suitable, inter alia, for graphics applications. In this mode, the resolution can be the same as that of a corresponding 3-primary display (e.g. 1280 x 1024 pixels for black-and-white graphics, for example, using a SXGA display, yielding an effective resolution of 3840 x 1024 pixels, instead of the original 1280 x 1024 resolution. The arrangement and handling of the pixels for this mode of operation may be as in the high resol tion, "limited gamut" mode described above. Additional modes of operation are also possible m accordance with embodiments of the invention; such additional modes may be designed in accordance with specific display requirements. Fig. 13B schematically illustrates possible data flow schemes for a 6-primary display system in accordance with exemplary embodiments of the invention, using RGB-CMY primary color sets as described above. In this example, the resolution of the mput data is assumed to be at the original resolution of the display; otherwise, appropriate scaling may be required as described above. A pixel collector 1302 collects image data corresponding to a pair of three-priraary pixels, namely, a RGB pixel and a CMY pixel, which together form a single 6-primary pixel. The original image data may be provided in any suitable format known in the art, for example, RGB or YCC format. Using matrix multiplication units 1304 and 1306 and, subsequently, an n-primary combiner 1308, the collected data of the two three-color pixels is converted mto gray-scale values for the different sub-pixels. If the color values of both pixels fall within the shadowed hexagonal area in Fig. 13A, e.g., if all the sub-pixels have positive gray scale values, then the gray levels used to drive the respective LC sub-pixels are unchanged. Referring to Fig. 13A, when the input data falls outside the CMY triangle but within the RGB triangle, the data may be handled in a number of different manners, depending on the specific application. In one embodiment, the data is represented only by the RGB sub-pixel component, and the CMY component is set to zero illumination. In another embodiment, the input data is represented by the RGB component, and the CMY component represents the color combination nearest the desired color. For the purpose of this embodiment of the invention, the "nearest" color combination may be defined in terms of brighmess, chromaticity, or simply by setting any negative sub-pixel values to zero. In a further embodiment, the CMY component represents the color combination nearest as possible to the desired color, and any difference between the desired color and the CMY representation is con'ected by the RGB component. The three different embodiments discussed above differ mainly in the method of presenting saturated colors. In the first embodiment, saturated colors are reproduced accurately, from colorimetric point of view, but at a relatively low brightness level. In the second embodiment, the brightness level is maximized, but saturation is decreased. In the third embodiment, the saturation and brightness level fall within the range in between the maximum and minimuin levels of the first and second embodiments. It should be appreciated that, by transposing the references to CMY and RGB, respectively, in the above analysis, the same analysis applies to a situation in which the input data falls outside the RGB triangle but within the CMY triangle in Fig. 13 A. Referring to Fig. 13 A, it should be noted that any color combination within the 6-color gamut (the peripheral dotted hexagon) that falls outside the "star of David" shape formed by the conjoined triangular areas of the RGB gamut and CMY gamut, can be reproduced accurately only by the full six-primary pixel representation. In an embodiment of the invention, an algorithm using two-dimensional look-up-tables ("LUTs"), as described in Applicants' pending International Application PCT/IL02/00410, filed May 23, 2002, entitled "System and method of data conversion for wide gamut displays", the disclosure of which is incorporated herein by reference, may be applied to derive the correct sub-pixel values for all six primaries in real time. In this embodiment of the invention, the average color of the RGB and the CMY combinations may be calculated, and the resulting color may be transformed, e.g., using a six-primary converter, to produce the sub-pixel coefficients of the corresponding n-primary pixel. The systems and methods described above are suitable for display devices in which colors are perceived by spatial integration of the sub-pixels by the human vision system. However, color integration by the human vision system can also be performed temporally and, therefore, embodiments of the present invention also provide sequential display devices, systems and methods, for example, sequential color LCD devices, using more than three primary colors. This concept is described m detail, in the context of sequenctial n-primary color image projection devices, in Applicants' International Application PCT/ILOl/00527, entitled "Device, System and Method For Electronic True Color Display", filed June 7, 2001, and published December 13, 2001 as WO 01/95544, the entire disclosure of which is incorporated herein by reference. In sequential projection color displays devices, four or more different color fields are projected sequentially, each for a short time period, and the process is repeated periodically at a sufficiently high frequency, whereby the human vision system temporally integrates the different color fields into a full color image. An advantage of LCD devices based on sequential color representation, in accordance with embodiments of the present invention, is that such devices can display more-than-three-primary color images at a resolution comparable to the resolution at which the same devices can display tlu'ee-primary-color, e.g., RGB, images. Sequential LCD display devices do not require a color sub-pixel filter matrix in registry with the LCarray. Instead, each LC element controls the intensity of all the primary colors for a given pixel, each primary color being conti'olled during designated time slots, whereby the LC array is utilized-to its full resolution. Color combinations are created by sequentially back-illuminating the LC array with different primary colors, in analogy to sequential projection devices. However, in contrast to projection devices, which typically require significant physical space to contain the projection optics, namely, the optical setup that projects a miniature spatial light modulator onto a screen, the sequential LCD device of the present invention does not require projection optics and may, thus, be implemented in flat configui-ations. the architecture of a flat n-primaiies display according to an embodiment of the present invention includes an LC array (panel) having a desired size and resolution. Such LCD panels are used, for example, in portable computers as are known in the ail. However, in the sequential LCD defaces of the present invention, the LC panel may be used without an adjacent array of color sub-pixel filters, whereby the LC array may operate as a monochromatic gray level device. The. cells of the LC an*ay are selectively attenuated to produce a. series of more-than-three primary gray-level patterns, each pattern corresponding to one of more-than-three primary color components of the displayed image. Each gray-level pattern is back-illuminated with light of the corresponding primary color. Switching among the different back-illuminations colors is synchronized with the sequence of gray-level patterns produced by the LC array, whereby each gray level pattern in the sequence is illuminated with light of the correct primary color. The light for the desired back-illumination may be produced by filtering white light (or other color light) through pre-selected color filters, each filter corresponding to one of the more-than-three primary colors. The back-illumination color sequence is repeated at a sufficiently high frequency, synchronized with the periodic sequence of pattems produced by the LC array, whereby the viewer perceives a full color image by temporal integration of the as described above. Parts of a sequential LCD device in accordance with an embodiment of the invention are schematically illustrated in Fig, 14. It should be appreciated that the sequential color LCD devices described herein illustrate only an exemplary embodiment of the invention. In alternate embodiments of the invention, other systems and methods may be used to create the different colors of back-illumination light. Additionally or alternatively, in some embodiments of the invention, instead of using an LC array as described above,other methods known in the art may be used to sequentially produce the gray level patterns corresponding to the different primary color components. In one enrbodiment of the invention, illustrated schematically in Fig. 14, the different illumination colors are produced sequentially, using a single light source, or a set of light sources, for example, a white light source 1410, by sequentially filtermg the white light through a series of different color fdters 1413. The color filters may be placed on a rotating filter wheel 1412. To obtain the desired back-illumination, the colored light passing through one of color filters 1413 on filter wheel 1412 may be focused, e.g., using a lens 1414, into a light guide 1416. The light guide funnels the filtered hght to a back-illumination arrangement 1422 juxtaposed an LC array 1420, as known in the art, illuminating the LC array substantially uniformly. In some variations of this embodiment, the back-illumination arrangement and light guide are similar to those used in back-illuminated portable computers, e.g., laptop computers, or in light-table devices. In some such devices, light from fluorescent light bulbs is reflected by an arrangement of reflectors/diffusers to obtain substantially uniform illummation. Alternatively, as shown schematically in Fig. 14, the light funnel 1416 may mclude multiple light exits 1418 that may be used in conjunction with reflectors/diffusers in back-illumination arangement 1422 to obtain uniform illumination. In alternate embodiments other structures may be used to provide back-illumination of different primary colors. In alternate embodiments of the invention, the back-illumination is generated by an array of Light Emitting Diodes (LEDs), each LED capable of selectively producing light at one of more than three different wavelength ranges. The different color LED emissions are activated sequentially, and the color sequence is synchronized with the sequence of gray-level patterns produced by the LC array. la a three-primary, e.g., RGB, device using LED back-illumination, in order to obtain a sufficiently wide color gamut, the red, green and blue LED emissions are typically designed to have narrow respective spectra. In particular, the peak of the emission distribution of such devices is typically in the range of 630-680 nm for the red emission, 500-540 nm for the green emission, and 400-480 nm for the blue emission. Unfortunately, existmg three-color devices do not utilize the brightness-efficient wavelength range of 540-570 mn, perceived as orange-yellow light, at which wavelength range the human eye is most sensitive. Therefore, adding a fourth LED emission in the range of 540-570 nm, in accordance with embodiments of the invention, can significantly improve the brightness efficiency. Assuming that the quantum efficiency of all diodes is substantially the same, a yellow LED would produce more visual brightness per Ampere. To talce advantage of this efficiency, by activating the four LED emission ranges described above, in some embodiments of the invention, at least four primary colors, namely, red, green, blue and yellow-orange, are used. In an alternative embodiment of the invention, instead of using a fourth emission range, an array of standard RGB LEDs may be activated in accordance with an activation sequence that produces a higher intensity of the desired back-illumination sequence, Instead of the standard activation sequence of R-G-B-R-G-B, some embodiments of the invention use a hybrid periodic activation sequence, for example, R-G-B-RG-BG-RB, to produce the desired back-illumination sequence. Other activation sequences of the RGB LED emissions are also possible, for example, sequences mcluding the same emission components (e.g., R, G, B, RG, BG and RB) arranged in different orders, sequences in which some of the "mixed" components (e.g., RG, BG, or RB) are omitted, sequences including additional components (e.g., a full RGB emission component), or any other suitable combinations of "pure" and/or "mixed" LED emissions capable of produce the desired back-illumination sequence. It should be appreciated that the over-all brightness level produced by the exemplary activation sequence of R-G-B-RG-BG-RB, determined by the smn 3R+3G+3B, is about 50 percent higher than the average brightness produced by a corresponding standard R-G-B-R-G-B sequence, determined by the sum 2R-I-2G+2B. The sequential LCD device in accordance with embodiments of the invention is activated at a sufficiently high frequency to enable a viewer to temporally integrate the sequence of n-primary images into a full color image. Additionally, to produce a video image, the sequential LCD device in accordance with embodiments of the invention is activated at a sufficiently high rate to enable reproduction of the required number of frames per second. A sequential color LCD device that operates at a sufficiently fast rate, using back-illumination of three primary colors, namely, red, green a blue light, is described in Ken-ichi Takatori, Hiroshi Imai, Hideld Asada and Masao Imai, "Field-Sequential Smectic LCD with TFT Pixel Amplifier", Functional Devices Research Labs, NEC Corp., Kawasaki, Kanagawa 216-8555, Japan, SID 01 Digest, incorporated herein by reference. In an embodiment of the present invention, a version of this three-color device is adapted to produce n-primary color images, wherein n is greater than three. In such n-primary n-adapted sequential illumination device, light generated by a (preferably) white light source is filtered through n, sequentially interposed, color filters, to produce the desired sequence of n-primary color back-illumination. A filter switching mechanism, for example, a rotating filter wheel including more than three different color filters, such as the filter wheel described above with reference to Fig. 14, may be used to sequentially interpose the different color filters in light path of the back-illumination. An arrangement similar to that used in existmg laptop computers may be used to funnel and diffuse the filtered light illuminating the LC array. In some embodiments, the light source and filter switching mechanism (or, alternatively, the array of LEDs described above) are housed in an external device, and a light guide is used to funnel colored light into the back-illumination arrangement of the LCD device, as described above with reference to the embodiment of Fig. 14. It will be appreciated by persons sldlled in the art that the present invention is not limited by what has been particularly shown and described hereinabove and with reference to the accompanying drawings. Rather, the invention is limited only by the following claims. CLAIMS 1. A color Liquid Crystal Display (LCD) device for displaying a color image using at least fouR different primary colors, the device comprising: an array of Liquid Crystal (LC) elements; driving circuitiy adapted to receive an input corresponding to said color image and to selectively activate the LC elements of said LC array to produce an attenuation pattern corresponding to a gray-level representation of said color image; and an array of color sub-pixel filter elements juxtaposed and in registry with said array of LC elements such that each color sub-pixel jlter element is in registry with one of said LC elements, wherein said array of color sub-pixel filter elements comprises at least four types of color sub-pixel filter elements, which transmit light of said at least four primary colors, respectively. 2. A device according to claim 1 wherein said at least four primary colors comprise red, green, blue, and yellow. 3. A device according to claim 1 wherein said at least four primary colors comprise at least five primary colors and wherein said at least four types of color sub-pixel filter elements comprise at least five types of color sub-pixel filter elements, Avhich transmit ligiit of said at least five primary colors, respectively. 4. A device according to claim 3 wherein said at least five primary colors comprise red, gi'een, blue, yellow, and cyan. 5. A device according to claim 3 wherein said at least five primary colors comprise at least six primary colors and wherein said at least five types of color sub-pixel filter elements comprise at least six types of color sub-pixel filter elements, which transmit light of said at least six primary colors, respectively. 6. A de-vice according to claim 5 wherein said at least six primary colors comprise red, green, blue, yellow, cyan, and magenta. 7. A color Liquid Crytal Display (LCD) device for displaymg a temporally-integrated color image comprising a sequence of at least four primary color images, the device comprising: an array of Liquid Crystal (LC) elements; driving circuitry adapted to receive an input corresponding to each of said at least four primary color images and to selectively activate the LC elements of said LC array to produce an attenuation pattern corresponding to a gray-level representation of each of said at least four primary color images, respectively; and an illumination system adapted to sequentially back-illuminate said LC array with light of at least four different primary colors to sequentially produce said at least four, respective, primary color images, Wherein said driving circuitry and said illumination system are synchronized such that each said attenuation pattern is illuminated with light of the primary color corresponding to the respective primary color image. 8. A device according to claim 7 wherein said at least four primary color images comprise red, green, blue, and yellow images. 9. A device according to claim 7 wherein said ai; least four primary color images comprise red, green, blue, yellow, and cyan images. 10. A device according to claim 7 wherein said at least four primary color images comprise red, green, blue, yellow, cyan, and magenta images. 11. A device according to any of claims 7-10 wherein said illumination system comprises: a light source having an output path; a filter switching mechanism which sequentially interposes at least four different prrimary color filters in the output path of said light source to produce said light of at least four different primary colors, respectively; and an optical arrangement which guides said light of at least four different primary colors from said filter switcliing mechanism to said LC array tliereby to back-illumuiate said LC array. 12. A device according to claim 11 wherein said light source comprises a substantially white light source. 13. A device according to any of claims 7-10 wherein said illummation system comprises: an array of Light Emitting Diodes (LEDs); illumination control circuitry adapted to selectively activate said plurality of LEDs to produce a sequence of at least four illumination patterns corresponding to said hght of at least four different primary colors, respectively; and an optical arrangement which causes the at least four illumination patterns produced by said array of LEDs to back-illuminate said LC array with a generally spatially homogeneous light of said at least four, respective, primary colors. 14. A device according to claim 13 wherein said array of LEDs comprises at -least three different color LEDs. 15. A device according to claim 14 wherem said at least three different color LEDs comprise red, green, and blue LEDs. 16. A devidce according to claim 14 or claim 15 wherein at least one of said at least four different illumination patterns corresponds to a primary color other than the colors of said at least three different color LEDs, 17. A device according to claim 15 or 16 wherein at least one of said at least four illumination patterns is produced by simultaneously activating at least two of said at least three different color LEDs. 18. A color display device for displaying an n-primary image, wherein n is greater than thi'ee, comprising an array of color sub-pixel elements including sub-pixel Qlements of each of at least four different primary colors arranged in an array of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure comprising a predetermined, fixed, number of n-primaxy pixels, each n-primary pixel comprising one color sub-pixel element of each of said at least four different primary colors, wherein no fixed combination of n-primary pixels covering only part of said super-pixel structure can be periodically repeated to cover substantially the entire n-primary image. 19. A color display device according to claim 18 comprising an n-primary color Liquid Crystal Display (LCD) device, wherem said array of color sub-pixel elements comprises an array of color sub-pixel filter elements, and wherein each n-primary pixel of each super-pixel comprises one color sub-pixel filter element transmitting light of each of said at least four different primary colors. 20. A device according to claim 18 or claim 19 wrherein said at least four different prunary colors comprise red, green, blue and yellow. 21. A device according to any of claims 18-20 wherein said at least four different primary colors comprise at least five different primary colors. 22. A device according to claim 21 wherein said at least five different primai'y colors comprise red, green, blue, yellow and cyan. 23. A device according to claim 21 or claim 22 wherein said snper pixel structure comprises a substantially rectangular arr angement including five sequences of four sub-pixel elements, each sequence iacluding a different combination of sub-pixel elements of four of said five primary colors. 24. A device according to claim 21 or claim 22 wherein said at least five different primary colors comprise at least six different primary colors. 25. A device according to claim 24 wherein said at least six different primary colors comprise red, green, blue, yellow, cyan and magenta. 26. A device according to claim 24 or claim 25 wherein said super pixel structure comprises a substantially rectangular arrangement including three sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of said six primary colors. 27. A method of displaying an n-primary color image, wherein n is greater than three, on an n-primary color display comprising an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors arranged in an array of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure comprising a predetermined, fixed, number of n-primary pixels, each n-primary pixel comprising one color sub-pixel element of each of said at least four different primary colors, wherein no fixed combination of n-primary pixels covering only part of said super-pixel structure can be periodically repeated to cover substantially the enlire u-primary image, the method comprising: receiving an input representing three-component color image data including a pluxality of thee-component pixels and having a first resolution; scaling said three-component color image data to produce scaled three-component color image data having a second resolution different from said first resolution; converting said scaled three-component color image data into corresponding n-primary color pixel data representing said n-primary color image; and generating an n-primary input signal corresponding to said n-primary color pixel data. 28. A method according to claim 21 fiirtlier comprising, before generating said n-primary input signal: collecting the n-primary color pixel data of all n-primary pixels of each super-pixel; and distributing the collected data representing each super-pixel structure into a plurality of sub-pixel data segments, each data segment representing one sub-pixel of each said super-pixel, wherein generating said n-primary input signal comprises generating a gray-level value for each of said sub-pixels. 29. A method according to claim 27 or claim 28 wherein said n-primary color display comprises an n-primary color Liquid Crystal Display (LCD) device, wherein said array of color sub-pixel elements comprises an array of color sub-pixel filter elements, and wherein each n-primary pixel of each super-pixel comprises one color sub-pixel filter element transmitting light of each of said at least four different primary colors. 30. A method according to any of claims 27-29 wherein said at least four different prmiary colors comprise red, green, blue and yellow. 31. A method according to any of claims 27-30 wherein said at least-four different primary colors comprise at least five different primary colors. 32. A method according to claim 31 wherein said at least five different primary colors comprise red. green, blue, yellow and cyan. 33. A method according to claim 31 or claim 32 wherein said super-pixel stmctui"e comprises a substantially rectangular an'angement including five sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of said five primary colors. 34. A method according to claim 31 wherein said at least five different primary colors comprise at least six different primary colors. 35. A method according to claim 34 wherein said at least six different primary colors comprise red, green, blue, yellow, cyan and magenta. 36. A method according to claim 34 or claim 35 wherein said super-pixel structure comprises a substantially rectangular arrangement including three sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of said six primary colors. 37. A method of displaying an n-primary image, wherein n is greater than or equal to six, on an n-primary display comprising an array of color sub-pixel elements including color sub-pixel elements of each of at least six different primary colors, including at least a first set of primary colors and a second set of primary colors, arranged in a periodically repeating arrangement comprising at least one color sub-pixel element of each of said at least six different primaiy colors, the method comprising: receiving an image input representing image data including a plurality of pixels, each pixel including one sub-pixel of each of said first set of primary colors; separating said image data into a first image component, including a first group of said pixels, and a second image component, including a second group of said pixels, wherein each pixel in said first group is substantially adjacent to a respective pixel in said second group; converting the pixels in said second group into corresponding, converted pixels, each pixel including one sub-pixel of each of said second set of piimaiy colors; and generating an n-primary input signal representing data corresponding to each of said converted color pixels in said second group and the respective, substantially adjacent, pixel in said first group. 38. A method according to claim 37 wherein said at least six different primaiy colors comprise red, green, blue, yellow, cyan and magenta, wherein said first set of primary colors comprises red, green and blue, and wherein said second set of primary colors comprises yellow, cyan and magenta. 39. A method according to claim 37 or claim 38 comprising, before generating said n-primary input signal, combniing each of said converted pixels in said second group with the respective, substantially adjacent, pixel of said first group, to produce a corresponding n-primary pixel including one sub-pixel of each of said at least six primaiy colors, wherein generating said n-primary input signal comprises generating a signal representing data corresponding to each said n-primary pixel.40. A method according to claim 37 or claim 38 wherein said image input comprises a color image input representing three-component color image data, wherein said at least first and second sets of primary colors comprise first and second sets of three primary colors, and wherein each color pixel of said n-primary image is reproduced by either the first or second set of three primary colors. 41. A method according to claim 37 or claim 38 wherein said image input comprises a black-and-white image input representing black-and-white image data including a plurality of black-and-white pixels. 42. A method according to claim 41 wherein said at least first and second sets of primaiy colors include first and second sets of three, complementary, primary colors, and wherein each black-and-white pixel of said n-primary image is produced by either the first or second set of primaiy colors. 43. A method according to claim 41 wherein said at least first and second sets of primary colors include first, second and third pairs of complementaiy primary colors, and wherein each black-and-white pixel of said n-primary image is produced by one of the first, second and third pairs of primaiy colors. 44. A color display device for displaying an n-primary image, wherein n is greater than or equal to six, comprising an array of color sub-pixel elements including color sub-pixel elements of each of at least six different primaiy colors, including at least a first set of primaiy colors and a second set of primaiy colors, arranged in a periodically repeating arrangement comprising at least one color sub-pixel element of each of said at least six different primary colors, wherein each sub-pixel m the periodically repeating arrangement is adjacent at least one sub-pixel of a complementary primary color. 45. A device according to claim 44 wherein said at least six different primary colors comprise red, green, blue, yellow, cyan and magenta, wherein said first set of primary colors comprises red, green and blue, wherein said second set of primary colors comprises yellow, cyan and magenta, wherein each red sub-pixel element is adjacent at least one cyan sub-pixel element, wherein each green sub-pixel element is adjacent at least one magenta sub-pixel element, and wherein each blue sub-pixel element is adjacent at least one yellow sub-pixel element. 46. A device according to claim 44 or claim 45 wherein said periodically repeating arrangement comprises a first sequence of sub-pixel elements of each of said frrst set of primary colors and a second sequence of sub-pixel elements of each of said second set of primary colors, wherein each sub-pixel element in the first sequence is adjacent a sub-pixel element of a complementary primaiy color in the second sequence. 47. A device according to claim 46 wherein said periodically repeating arrangement comprises first and second, adjacent rows of sub-pixel elements, the first row including one sub-pixel element of each of said first set of primary colors and the second row including one sub-pixel element of each of said second set of primary colors, and wherein each sub-pixel element in the fnst row is adjacent a sub-pixel element of a complementary primary color in the second row. 48. A device according to any of claims 44-47 wherein each row of said array of sub-pixel elements includes only sub-pixels of said first set of primary colors. 49. A device according to any of claims 44-47 wherein each row of said array of sub-pixel elements includes sub-pixels of both said first and second sets of primary colors. 50. A system for displaying an n-primary color image, wherein n is greater than three, comprising: an n-primary color display device comprising an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors arranged in an array of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure comprising a predetermined, fixed, number of n-primaiy pixels, each n-primary pixel comprising one color sub-pixel element of each of said at least four different primary colors, wherein no fixed combination of n primary pixels covering only part of said super-pixel structure can be periodically repeated to cover substantially the entire n-primary image; means for receving an input representing three-component color image data including a plurality of three-component pixels and havmg a first resolution; a scaling unit, which scales said three-component color image data to produce scaled three-component color image data having a second resolution different from said first resolution; a converter which converts said scaled three-component color image data into coiresponding n-primary color pixel data representing said n-primary color image; and means for generating an n-primary input signal corresponding to said n-primary color pixel data. 51. A System according to claim 50 further comprising: a collection unit which collects the n-primary color pixel data of all n-primary pixels of each super-pixel; and a distribution unit, which distributes the collected data representing each super-pixel strcuture into a plurality of sub-pixel data segments, each segment representing one sub-pixel of each said super-pixel, wherein said means for generating said n-parimary input signal generates a gray-level value for each of said sub-pixels. 52. A system according to claim 50 or claim 51 wherein said n-primary display device comprises an n-primary Liquid Crystal Display (LCD) device, wherein said array of color sub-pixel elements comprises an array of color sub-pixel filter elements, and wherein each n-primary pixel of each super-pixel comprises one color sub-pixel filter element transmitting light of each of said at least four different primary colors. 53. A system according to any of claims 50-52 wherein said at least four different primary colors comprise red, green, blue and yellow. 54. A system according to any of claims 50-53 wherein said at least four different primary colors comprise at least five different primary colors. 55. A system according to claim 54 wherein said at least five different primary colors comprise red, green, blue, yellow and cyan. 56. A system according to claim 54 or claim 55 wherein said super-pixel struture comprises a substantially rectangular arrangement including five sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of said five primary colors. 57. A system according to claim 54 wherein said at least five different primary colors comprise at least six different primary colors. 58. A system according to claim 57 wherein said at least six different primary colors comprise red, green, blue, yellow, cyan and magenta. 59. A system according to claim 57 or claim 58 wherein said super-pixel structure comprises a substantially rectangular arrangement including three sequences of four sub-pixel elements, each sequence including a different combination of sub-pixel elements of four of said six primary colors. 60. A system for displaying an n-primary image, wherein n is greater than or equal to six, comprising: an n-primary display device comprising an array of color sub-pixel elements including color sub-pixel elements of each of at least six different primary colors, including at least a first set of primary colors and a second set of primary colors, arranged in a periodically repeating arrangement comprising at least one color sub-pixel element of each of said at least six different primary colors. an image collector which receives an image input representing image data including a plurality of pixels, each pixel including one sub-pixel of each of said first set of primary colors; means for separating said color image data into a first image component, including a first group of said pixels, and a second image component, including a second group of said pixels, wherein each pixel in said first group is substantially adjacent to a respective pixel in said second group; means for converting the pixels in said second group into corresponding, conveited pixels, each pixel including one sub-pixel of each of said second set of primary colors; and means for generating an n-primary input signal representing data corresponding to each of said conveited color pixels in said second group and the respective, substantially adjacent, pixel in said first group. 61. A system according to claim 60 wherein said at least six different primary colors comprise red, green, blue, yellow, cyan and magenta, wherein said first set of primary colors comprises red, green and blue, and wherein said second set of primary colors comprises yellow, cyan and magenta. 62. A system according to claim 60 or claim 61 further comprising a pixel combiner which combines each of said converted color pixels in said second group with the respective, substantially adjacent, pixel of said first group, to produce a corresponding n-primary pixel including one sub-pixel of each of said at least six primary colors, wherein said means for generating said n-primary input signal generates a signal representing data corresponding to each said n-primary pixel. 63. A system according to claim 60 or claim 61 wherein said image input comprises a color image input representing three-component primary color image data, wherein said ast first and second sets of primary colors comprise first and second sets of three primary colors, and wherein each color pixel of said n-primary image is reproduced by either the first or second set of three primary colors. 64. A system according to claim 60 or claim 61 wherein said image input comprises a black-and-white image input representing black-and-white image data including a plurality of black-and-white pixels. 65. A system according to claim 64 wherein said at least first and second sets of primary colors include first and second sets of three, complementary, primary colors, and wherein each black-and-white pixel of said n-primaiy image is produced by either the first or second set of primary colors. 66. A system according to claim 64 wherein said at least first and second sets of primary colors include first, second and third pairs of complementary primary colors, and wherein each black-and-white pixel of said n-primary image is produced by one of the first, second and third pairs of primary colors. 67. A system according to any of claims 60-66 wherein said n-primary display device comprises an n-primary Liquid Crystal Display (LCD) device, and wherein said array of color sub-pixel elements comprises an array of color sub-pixel filter elements including filter elements transmitting light of each of said at least six different primary colors. 68. A method according to any of claims 37-43 wherein said n-primary display device comprises an n-primary Liquid Crystal Display (LCD) device, and wherein said may of color sub-pixel elements comprises an array of color sub-pixel filter elements including filter elements transmitting light of each of said at least six different primary colors. 69. A device according to any of claims 44-49 wherein said n-primary display device comprises an n-primary Liquid Crystal Display (I-CD) device, nnd wherein said array of color sub-pixel elements comprises an array of color sub-pixel filter elements including filter elements transmitting light of each of said at least six different primary colors. 70. A device according to any of claims 1-26 wherein the wavelength ranges of said at least four primary colors are selected to provide an optimal over-all brightness of the displayed images. 71. A device according to any of claims 1-26 wherein the wavelength ranges of said at least four primary colors are selected to provide an optimal color gamut width of the displayed images. 72. A method according to any of claims 27-36 wherein the wavelengtli ranges of said at least four primary colors are selected to provide an optimal over-all brightness of the displayed images. 73. A method according to any of claims 27-36 wherein the wavelength ranges of said at least four primary colors are selected to provide an optimal color gamut width of the displayed images. 74. A method according to any of claims 37-43 wherein the wavelengtli ranges of said at least six primary colors are selected to provide an optimal over-all brightness of the displayed images. 75. A method according to any of claims 37-43 wherein the wavelength ranges of said at least six primary colors are selected to provide an optimal color gamut width of the displayed images. 76. A device according to any of claims 44-49 wherein the wavelength ranges of said at least six primary colors are selected to provide an optimal over-all brightness of the displayed images. 77. A device according to any of claims 44-49 wherein the wavelength ranges of said at least six primary colors are selected to provide an optimal color gamut width of the displayed images. 78. A system according to any of claims 50-59 wherein the wavelength ranges of said at least four primary colors are selected to provide an optimal over-all brightness of the displayed images. 79. A system according to any of claims 50-59 wherein the wavelength ranges of said at least four primary colors are selected to provide an optimal color gamut width of the displayed images. 80. A system according to any of claims 60-66 wherein the wavelength ranges of said at least six primary colors are selected to provide an optimal over-all brightness of the displayed images. 81. A system according to any of claims 60-66 wherein the wavelengtli ranges of said at least six primary colors are selected to provide an optimal color gamut width of the displayed images. 82. A color display device for displaying an n-primary image, wherein n is greater than three, comprismg an array of color sub-pixel elements including sub-pixel elements of each of at least four different primary colors arranged in an an*ay of periodically repetitive super-pixel structures covering substantially the entire n-primary image, each super-pixel structure comprising a predetermined, fixed, number of n-primary pixels, each n-primary pixel comprising one color sub-pixel element of each of said at least four different primary colors, wherein the sub-pixel elements in each super-pixel structure are arranged in a rectangular sub-array having an average aspect ratio sufficiently close to one.

Documents:

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1975-chenp-2003 abstract-duplicate.pdf

1975-chenp-2003 claims granted.pdf

1975-chenp-2003 claims-duplicate.pdf

1975-chenp-2003 description (complete)-duplicate.pdf

1975-chenp-2003 drawings-duplicate.pdf

1975-chenp-2003-abstract.pdf

1975-chenp-2003-claims.pdf

1975-chenp-2003-correspondence others.pdf

1975-chenp-2003-correspondence po.pdf

1975-chenp-2003-description complete.pdf

1975-chenp-2003-drawings.pdf

1975-chenp-2003-form 1.pdf

1975-chenp-2003-form 18.pdf

1975-chenp-2003-form 3.pdf

1975-chenp-2003-form 5.pdf

1975-chenp-2003-pct.pdf