Title of Invention


This invention relates to an optical instrument by which one can measure the power of optical lens (in diopter) required in eye of a person having (I) Long Sight (Myopia), (ii) Short Sight (Hypermetropia) or (iii) Astigmatism.
In conventional system trial and error method is applied by lot of lenses to determine the power of lens required for a person having Short sight, Long sight or Astigmatism problem. It takes time. It may not be accurate. Doctor can loose his patience. Computer can not give always-accurate results.
In this device described here, a couple of liquid lens is used for each eye to determine any power of lens required, by electrical operation. No changing of lens is required. Power can be determined for spherical or cylindrical lens. Both spherical and cylindrical power for a single lens
can be obtained in this device. The angle of axis of a cylindrical lens can

also be found here. It will take little time and the power detected will be most accurate.
The object of this invention is to determine the power of lens required for a person having Short Sight or Long Sight or Astigmatism or mixed problem by easy electrical operation with the help of liquid lens.
There are two types of liquid lens used in this optical device. One is circular and another is rectangular in shape (section). Each lens is containing liquid inside. Shape of that liquid can be changed. That liquid behaves as lens of changeable power.. One side of liquid lens is covered by plain glass and opposite side is covered by a transparent and thin elastic membrane (e.g.: a highly stretched condom). Distilled water or glycerin can be used as liquid inside the chamber of le ,ns. In normal stage both plane of elastic membrane and glass remains parallel. Then the power of lens is zero. When more liquid is added, the inner pressure is increased. The elastic membrane will then go out and try to equalize inner pressure to outer pressure. Then the liquid inside behaves as a
convex lens. Similarly, when some amount of liquid is extracted from the lens, the membrane will come inside. Then the lens acts as a concave lens. Circular shaped lens acts as spherical lens and Rectangular shaped lens acts as cylindrical lens. In this device adding and extraction of liquid is done by use of a small pump (a syringe is used here) having a piston in it. The piston can be moved front and back by a motor with help of some toothed gears. The shaft of motor rotates both way (clock-wise and anticlockwise). If clockwise rotation of shaft makes adding of liquid to lens then anti-clockwise rotation makes extraction of liquid from lens. The operation of piston can be done manually also. Now a person who is having problem in eyes as mentioned before, will wear the lens container on his eyes with help of belt. He will be told to see any object or read any writing, generally he feels trouble to read them. A Doctor or an examiner then will operate the operating box with help of valves and switches to change the power of liquid lens as desired. The liquid can also be rotated vertically at a time. The pointer will indicate the power of lens (required) on the scale in the operating box just when the person can see the object very clearly and vividly. The angle of rotation of cylindrical lens is displayed in the top of lens container. The pointer is associated with suitable gears by pulley and belt. The pointer will go up or down by big

range for little displacement of the piston in the pump(syringe). A lever (piston rod) attached to it, the surface of which is like tooth of gear will move the piston.
Reference is now made to the accompanying drawing-Figure 1 is a overall view of lens container.
Figure 2 is the overall view of operating box.
Figure 3 and 3 (a) show the structure of the lens container.
Figure 4 shows the structure of the lens container with the liquid lens.
Figure 5 shows the section of a set of liquid lenses for each eye.
Figure 6 shows the front view of liquid lens to determine the power of spherical lens.
Figure7 shows the front view of liquid lens to determine the power of cylindrical lens.
Figure 8 (a-j) shows details of guard plate, membrane disk and their location of placing.
Figure 9(a), 9(b), 9(c) show the overall view of the lens container before and after wearing it by a person.
Figure 9(d) show the belt of iens container.
Figure 9(e) & 9(f) show top view of iens container and it"s inner structure with outer cover.
Figure 9(g-j) show the structure of the lens container and it"s sliding system.
Figure 10 (a) shows the mechanical system of the operating box with storage water pot.
Figure 10 (b) & 10 (c) show the mechanical system of the operating box.
Figure 11 (a), 11(b) & 11(c) show the electric connections and water flow connections respectively.
Figure 12 (a) shows a modification of the mechanism system using a bellow.
Figure 12 (b) shows a modification of rotating system of iiquid lens manually.
This mode consists two part. One is lens container 1 and other is operating box 32. Lens container 1 contains a structure or frame 41 which holds two sets of liquid lenses 51. Each set consists two lens. One is for determining the power of spherical lens 67 (sp-lens) and other is for determining the power of cylindrical lens 68 (cy-lens).
The structure 41 is made of light material like bakelite, steel or aluminum. It will be covered by a jacket 80 made of bakelite. A rubber beit 2 is fitted with it by which the lens container 1 can be worn on eye (fig-9 (b & c)). Two end of beit can be joined by pressing as shown in 77. The size or length of the lens container 1 can be changed by sliding curved iron plate (fig 9( h, i & j)). Plate 83 can be inserted inside plate 81. It will help to wear this container by a child or adult person. When the adjustment is OK", curved plate is to be tighten by screw 5. a circular frame 40 is there to hold the liquid lens 51. Two small teeth gears are present. One 49 is joined with the motor 48 to move the lens clockwise or anticlockwise by the help of rotator switch 34. Another gear 47 is for fine adjustment
(rotation) of iens if necessary, it is done by screw 7. Three keys 41,

42, 43 are there to hold the lens 51 with the circular frame 40. the liquid lens 51 can be rotated aiong the circulate frame 40. Two notch 45,46 are fitted with circular frame 40. The fork of lens 118 detain within these notches 45, 46. Thus it restrict the lens to rotate from 0° to 180 ° angle 71. There are two windows 4 in front of the cover 80 of lens container 1. Degree of rotation can be visible there for both eye during determination of power for cylindrical lens. Some tooth gears 50 are associated with motor 48 in the structure 41 of iens container to regulate the speed of motor.
A set of liquid lenses 51 is containing glycerin or distilled water 58 divided by a transparent fiat glass 57. Each outer side is made of transparent synthetic membrane 63. So, the liquid lens is a set of two lens (sp-lens & cy-iens) 67, 68. Membrane disks 65,66 are detachable. They are fitted in ditch 62, 76. Base of the disk 65, 69 is coated with rubber so that no liquid can come out of the lens 51 when it is operated. The membrane 63 will be well and equally starched all where. The membrane disk 65, 66 will be supported by guard plate 69, 55 which is made of steel. Two hooks 75, are there in each guard plate. Hooks 75 come under shoe 64 and fix the membrane disk 65, 66 tight altogether with ditch 62, 76. Sp-lens 67 wiil remain outside and cy-iens 68 wiil remain in side in the set of

liquid lenses 51. Cy-lens 68 will be eye piece. Cy-lens 68 and sp-lens 67 both are having inlet 61, 60 and outlet 6 pipe. Outlet pipe 6 is fitted with valve 70, 8 called pressure releasing valve. Central plate 59 is circular. It"s end is zigzag like teeth of gear. It is made of bakelite. It 59 can be rotated by the motor 48. Central plate 59 is demarked in scale 71 from 0 ° to 180 ° angle in outer face. Small fork 118 is standing on the central plate 59 and two cantilever pick (notch) 45, 46 are fitted from outside, which can control the rotation of lens 51 within 0 ° to 180 °. Central plate 59 is fitted by keys 42,43,44 after placing on circular frame 40. Fitting system for both lenses 67, 68 are same, just shape of lenses are different. Membrane disk, guard plate, ditch etc are shown in fig 8.
Operation is done by the help of operating box 32. Mechanism is shown in fig-10 and overall view is shown in fig 2. The box 32 consists two syring 90 and other for adding or reducing liquid from liquid lens 51 and other. Each syring 90 contains liquid 93. If it"s piston 91 is pressed inside the syring 90 will deliver liquid out side through pipe and vice-versa. Movement of piston 91 is controlled by a two-way motor 94 with the help of few tooth gear 95. Tooth gear are made of bakelite or any metal. There are two sets of syring and gear system 103, 104 in the operating box 32. Rotation direction of

motors 94, 106 are controlled by switch 33 & 34 for right & left eye.
Pointer 37 & 38 of scale is fitted with suitable gear for each syring
gear system 103, 104. The mechanism of syring-gear system is
shown in (fig - 10(b)). Movement of piston 91 is dimmed by few
gears 95. The number and size of gear wiil be fixed according to
requirement after practical experiment. Each syring 91 provides
liquid both for sp-lens 67 through cy-lens 68 through inlet pipes 60,
61 for each eye. Four stop valves are there to stop supply of liquid
to four lenses, mentioned as main switches 12, 15, 18 & 21.
Positive and negative marking is done in the scale and switches 28,
27. Scale 30 & 34 are for left & right sp-lens. Scale 31 & 35 are for
left & right cy-lens. Zero position in the scale is indicated by a line in
middle of scale. The unit of scale is in diopter. A plug 24 is there.
Three volt D.C. current is to be provided by an adaptor. A battery
case 105 is there where two battery (1.5 volt each) can be put to
supply the said voltage 119 if current is not available. Each motor
94, 106, 48 and another needs 3 volt for operation. One motor runs
at-a-time. So, all motors are supplied by this voltage through switch
25, 26, 34, 33. A storage liquid pot 84 is kept in the box 32. Liquid
from that pot 84 can be supplied to any syring or lens and pipe
through feed valve 11, 14, 17, 20. A lever 36 is fitted with the pot 84
by which liquid can be added or subtracted through pipe 109. Four

lenses are connected with syring by hard plastic pipe 114, 115, 116, 117 through stop valve 10, 13, 16, 19 mentioned here as rising valve. Valve 10, 11, 12, is for left sp-lens and valve 13, 14, 15 and switch 34 are for the left sp-lens. Switch 28 or 34 can be operated if switch 25 (off-on switch of motor of 103) is on. Switch 25 & 26 can be operated if main switch 9 is on. Switch 34 is rotator switch by which motor 48 in the lens container can be rotated in any direction. Switch 33 is for right cy-lens. Two way switch 28 & 27 can run motor in any direction to move the piston 91 upwards and downwards. There are two hole 23 & 22 in which two hooks or resting clamps 88 are fitted. The lens container 1 can be kept on clamp 88. A lid 85 is there over the liquid pot 84. The liquid pot 84 is having a cap 86. The liver is joined with hinge 87. Pointer 37 & 38 move along the scale 30-31 & 34 -35. Pointers are connected with belt 97, pulley 96 with suitable gear 98. Scale 34, valve 16, 17, 18 are for right sp-lens. Scale 35, valve 19, 20, 21, switch 27 are for right cy-iens. Four pipes 114, 115, 116, 117 and two electric cable (for two motor in lens container) 107 & 108 will go through the pipe 39. Pipe 114, 115 and cable 107 are for left liquid lens 51. And Pipe 116, 117 and cable 108 are for right liquid lens. All pipes and cables are going out through a single pipe 120 and splitted into two pipe 121 near the
lens container 1. Figure 11(c) shows details of stop valve used in

10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21. Each valve 110 is connected with the pipe 113. The way of pipe line is opened or closed by rotating the knob. The knob is shown in 111, 112.
Before operation ali lenses, pipes, syringes are to be filled with liquid. No bubble will be present in them, because it can bring error. Pointer 37, 38 will lie in zero position. Power of lenses are to be made zero by pressure releasing valve 6. The patient will wear the lens container 1 with use of belt 2 and sliding system shown in fig (h-j). Doctor will open one cap 79 of liquid lens for any one eye. The patient wiil be told to read or see any object generally he feels trouble to look that. The doctor will make the main switch 9 on. Vaive 12 & 10 wiil be open and 11 wiil be closed for determining the power of spherical lens 67 for left eye. The doctor will then make the switch 25 on. Then he will change the power of left sp-lens by operating switch 28. The pointer 37 will show the power of spherical lens required for left eye, on the scale 30. In case of cy-iens for left eye vaive 15 & 13 will be open and all remaining valves wiil be closed. The power wiil be obtained in scale 31 by operating switch 28. The angle of axis of cy-lens can be obtained by rotating the left liquid lens 51 with the use of switch 34. The angle will be visible in window 4. Thus both spherical and cylindrical power for single lens
can be obtained by operating valves and switches. Then power required for right eye can aiso be determined. Fixing ail power for both eyes the patient can be asked to look the object through both eyes before finalisation of power. An eye piece 78 in fitted in each lens inside. It 78 is like a piece of cylinder by which eye can not come in contact with membrane and the lens container can be fitted on eyes comfortably.
As the device is operated with help of gears, belts, piston etc calibration may be required after a period if errors are obtained in reading.
To fixing the scale, let us take a spherical lens of known power. Keep this lens in front of left sp-lens. Now, adjust the power of left sp-lens operating switch 28. Just when the total power of two lens (known power lens and sp-lens) is zero, the pointer will indicate same value of opposite power for the left liquid sp-lens. Thus ail power scaies are done both for sp-iens & cy-iens. Zero angle indicates that the long direction of cy-lens is lying horizontally. If it rotates anticlockwise by 90 ° the long direction of rectangular cy-iens wiii be lying vertically. It is to note that the cylindrical lens is having no power aiong its I9ong direction. The power changes just aiong its short direction. i 2__
In modification a bellow 122 here used instead of syringe 90. The bellow 122 is made of plastic or metal. Figure 12(a) shows details about it. A modification can also be made to rotate the liquid lens manually, which is shown in Figure 12(b). The lens 51 will rotate if the knob 124 is rotated by hand. One way gearl30 will resist the movement of knob 124. If one way gear 130 is released the knob will come back to it"s original position, because, a spring 127 is attached through a pulley 126 by belt 131. The iron wire 129 attached with knob 124 will rotate the lens. The wire lies in a flexible plastic pipe 123 having iron coil 132 inside.
7.1 CLAIM:
(1) An electrically or manually operated eye power testing device to determine the power of optical lenses (spherical or cylindrical) required in one or both eyes at a time of a person having Short sight(Myopia), Long sight(Hypermetropia) or Astigmatism or mixed problems, with use of liquid lenses, comprising two set of liquid lenses, each set containing two lenses, one lens(spherical lens)67 of which used to measure power (in diopter) of spherical lens and another lens (cylindrical lens)68 used to measure power of cylindrical lens, a lens container frame 41 to wear on eyes having gears 50 & motor 48 rotate each set 51 of liquid lenses along it"s (lens) axis, means for measuring the power of spherical or cylindrical or both lenses (convex) by adding liquid inside the lens, means for measuring the power of spherical or cylindrical or both lenses (concave) by reducing quantity of liquid inside the lens, means for measuring the angle of axis of cylindrical lens by rotating each set 51 of liquid lenses in the lens container frame 41 with help of motor 48, teeth gears 50, by electrical operation or manual, means for measuring power of both spherical optical lens (+ve or -ve) and cylindrical optical lens (+ve or -ve) with angle of axis at a time required for both eyes of a person by using two separate liquid lenses 67,68, attached in a set 51 by a common wall (flat & plain glass) 57, means for constructing the liquid lens using liquid 58 as construction material of lens covered by thin and
I if
transparent elastic membrane 63 in one end and flat & plain glass 57 in opposite end, means for preparing the scale 30,34 on the operating box 32 to indicate power (in diopter) for left and right spherical lenses and scale 31,35 for left and right cylindrical lenses in the lens container frame 41, means for displaying the rotation angle of the axis of cylindrical lens through the hole 5 of the lens container 41, means for replacing the damaged membrane by another fresh membrane , means for feeding liquid into lens after replacing of membrane disk or when necessary.
(2) An eye power testing meter as claimed in claim 1 wherein a frame 41 or structure is used which is holding two said set 51 of liquid lenses, made of bakelite or steel or aluminum, sliding system by which the size of the frame can be changed.
(3) An eye power testing meter as claimed in claim 1 wherein syringe 90 is used in the operating box 32 to provide or subtract liquid from said liquid lenses 67,68, mechanism by teeth gears 95 to regulate the movement of the piston 91, piston rod 92 attached to piston 91 having teeth as gear in it"s body, size and number of gear are fixed by practical observation .
(4) An eye power testing meter as claimed in claim 1 wherein liquid 58 inside the said spherical lens 67 acts as convex or concave lens when quantity of liquid is added or subtracted to it , similarly liquid inside the cylindrical lens 68 acts as convex or concave cylindrical lens when quantity of liquid is added or
subtracted to the lens, the spherical liquid lens 67 has power along any direction perpendicular to it"s central axis (except zero power position) , the cylindrical lens 68has power along it"s short direction/axis perpendicular to it"s central axis and has no power along long direction/axis (except zero power position).
(5) An eye power testing meter as claimed in claim 1 wherein the said set of liquid lens can be rotated manually also by the use of knob 124, spring 127, gear 130, pulley 126, iron wire 129, and spring pipe 123.
(6) An eye power testing meter as claimed in claim 3 wherein the said syringe 190 may be replaced by bellow which is made of plastic or metal.
(7) An eye power testing meter for determining the power of spherical or cylindrical lens substantially as described herein and illustrated in the accompanying drawings.
Eye power testing meter is an electrically operated optical instrument to measure
the power of lens required for eye of a person by easy electrical operation with the
help of liquid lens.
Chamber is closed by flat transparent glass and transparent synthetic membrane.
This chamber can be voted as desired,
The pointer wiil indicate the power of lens required on the scale.
The pointer is asociated with suitable gear by palley and belt,
which hilps in displacement.





00636-cal-2002-description (complete).pdf


00636-cal-2002-form 1.pdf

00636-cal-2002-form 2.pdf

00636-cal-2002-form 3.pdf

00636-cal-2002-form 5.pdf

00636-cal-2002-letter patent.pdf


Patent Number 211703
Indian Patent Application Number 636/CAL/2002
PG Journal Number 45/2007
Publication Date 09-Nov-2007
Grant Date 07-Nov-2007
Date of Filing 18-Nov-2002
Name of Patentee KAR SWAPAN BIKASH
# Inventor's Name Inventor's Address
PCT International Classification Number A61B 3/10
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA