US3918796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid-crystal non-linear light modulators using electric and magnetic fields
Assignee: F Hoffmann La Roche AG
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Filing: 1973-01-24
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Granted: 1975-11-11
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Expires: 1993-01-24
Abstract
Abstract A liquid-crystal unit comprising first and second pieces of flat glass, each coated on one side with a transparent electroconductive oxide coating and each having its so-coated surface rubbed with cotton cloth or the like in one direction, with the two surfaces so rubbed then being spaced about 1/4 to 2 mils apart and with a nematic-phase liquid-crystal material of positive dielectric anisotropy in between, and with the directions of rubbing being oriented substantially perpendicular to each other. Such a liquid-crystal unit has the particular property that when there is no potential applied to the electroconductive coatings and the unit is placed between crossed polarizers, light is transmitted, but the application of but a relatively low voltage across the two above-mentioned coatings, something on the order of 5 volts, will generate an electric field that causes the nematic-phase liquid-crystal material to ''''untwist,'''' so that it no longer permits transmission of light through the structure comprising the liquid-crystal unit and the crossed polarizers. The effect is quick-acting and reversible. Conversely, with parallel polarizers stationed to each side of such a unit, the effect is the opposite; with no voltage applied, no light is transmitted through the structure, but the application of sufficient voltage makes light transmission possible. The effect is sufficiently clear-cut and local that it is possible to use glass plates that have the electroconductive oxide coating provided only in certain selected areas thereof, with suitable bus bars or the like running to each, and thereby produce alpha-numeric displays. Logic elements, three-dimensional television, and numerous other applications suggest themselves to those skilled in the art.
Inventors
- 👤 James L Fergason
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:48
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/22; C09K19/02; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/1396; G02F1/13706; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
109 words
An optical device for continuous control of lght transmission comprising: electro-optical cell means including liquid crystal means having positive dielectric anisotropy disposed between two spaced plates, at least one of which plates is transparent and each plate being electrically conductive at a surface facing said liquid crystal means; said plates being wall-oriented to cause said liquid crystal means to define a twisted structure in the direction perpendicular to the plates; polarizing means disposed one before and one behind the liquid crystal means, in the direction of light traveling through the cell means; and electrical means connected to the plates for controlling the twisted structure of said liquid crystal means.
Claim 2
Dependent Claim
109 words
An optical device for continuous control of lght transmission comprising: electro-optical cell means including liquid crystal means having positive dielectric anisotropy disposed between two spaced plates, at least one of which plates is transparent and each plate being electrically conductive at a surface facing said liquid crystal means; said plates being wall-oriented to cause said liquid crystal means to define a twisted structure in the direction perpendicular to the plates; polarizing means disposed one before and one behind the liquid crystal means, in the direction of light traveling through the cell means; and electrical means connected to the plates for controlling the twisted structure of said liquid crystal means.
Claim 3
Dependent Claim
20 words
An optical device according to claim 1 wherein said liquid crystal means has a nematic phase which includes room temperature.
Claim 4
Dependent Claim
26 words
An optical device according to claim 1 wherein said liquid crystal means has a nematic phase in the temperature range of at least -10*C to 70*C.
Claim 5
Dependent Claim
14 words
An optical device according to claim 2 wherein said polarizing means comprises dichroic films.
Claim 6
Dependent Claim
50 words
An optical device according to claim 4 wherein the surfaces of the plates facing the liquid crystal means are covered with a film of a transparent conductive material and wherein said dichroic films are deposited on said films of conductive material and are in contact with said liquid crystal means.
Claim 7
Dependent Claim
12 words
An optical device according to claim 5 wherein both plates are transparent.
Claim 8
Dependent Claim
61 words
An optical device according to claim 2 wherein the plates have a transparent conductive material on each of said facing surfaces and said electrical means includes connecting leads in operative contact with the conductive material for applying a voltage to the plates, said electrical means being adapted to apply an electrical field across the liquid crystal means perpendicular to the plates.
Claim 9
Dependent Claim
24 words
An optical device according to claim 1 wherein said facing surfaces of the plates are unidirectionally rubbed in non-parallel directions relative to one another.
Claim 10
Dependent Claim
22 words
An optical device according to claim 8 wherein said surfaces of the plates are rubbed unidirectionally at right angles to each other.
Claim 11
Dependent Claim
18 words
An optical device according to claim 9 wherein the two polarizing means are oriented parallel to one another.
Claim 12
Dependent Claim
14 words
An electro-optical device according to claim 9 wherein said two polarizing means are crossed.
Claim 13
Dependent Claim
17 words
An optical device according to claim 9 wherein said plates are spaced 0.05 to 5 mils apart.
Claim 14
Dependent Claim
20 words
An optical device according to claim 2 wherein said liquid crystal means consists essentially of a nematic liquid crystal material.
Claim 15
Dependent Claim
95 words
An optical cell for continuously passing substantially all incident polarized light comprising: two plates at least one of which plates is transparent; a substance between the plates consisting of a mixture of nematic liquid crystals, said mixture having positive dielectric anisotropy; said plates being wall oriented in non-parallel directions relative to one another for causing said mixture to define a twisted structure in a direction substantially perpendicular to the plates; and electrical means for providing an electrical field across said liQuid crystal mixture transverse to the plates for controlling the twisted structure of said mixture.
Claim 16
Dependent Claim
95 words
An optical cell for continuously passing substantially all incident polarized light comprising: two plates at least one of which plates is transparent; a substance between the plates consisting of a mixture of nematic liquid crystals, said mixture having positive dielectric anisotropy; said plates being wall oriented in non-parallel directions relative to one another for causing said mixture to define a twisted structure in a direction substantially perpendicular to the plates; and electrical means for providing an electrical field across said liQuid crystal mixture transverse to the plates for controlling the twisted structure of said mixture.
Claim 17
Dependent Claim
20 words
An optical cell according to claim 14 wherein said liquid crystal mixture is in its nematic phase at room temperature.
Claim 18
Dependent Claim
36 words
An optical cell according to claim 15 wherein said electrical means includes conductive means comprising a transparent conductive material on the facing surfaces of said plates and connecting leads for applying a voltage to the plates.
Claim 19
Dependent Claim
46 words
An optical cell according to claim 16 wherein the surfaces of the plates facing the liquid crystal mixture are each at least partially covered with said transparent conductive material and wherein the connecting leads are established for the purpose of applying voltage to the conductive material.
Claim 20
Dependent Claim
12 words
An optical cell according to claim 17 wherein both plates are transparent.
Claim 21
Dependent Claim
25 words
An optical cell according to claim 18 wherein the surfaces of the plates facing the liquid crystal mixture are rubbed to effect said wall orientation.
Claim 22
Dependent Claim
15 words
An optical cell according to claim 19 wherein the plate surfaces have a preferential direction.
Claim 23
Dependent Claim
22 words
An optical cell according to claim 18 wherein said surfaces of the plates are rubbed unidirectionally at right angles to each other.
Claim 24
Dependent Claim
32 words
An optical cell according to claim 15 wherein the wall orientation resides in a surface state of the plates exerting an orienting action on the molecules of the nematic liquid crystal mixture.
Claim 25
Dependent Claim
17 words
An optical cell according to claim 22 wherein said plates are spaced 0.05 to 5 mils apart.
Claim 26
Dependent Claim
186 words
A process for the control of light transmission comprising the steps of: providing an electro-optical cell having nematic liquid crystal means of positive dielectric anisotropy disposed between a pair of spaced plates at least one of which is transparent and means for enabling an electrical field to be applied across the liquid crystal means, said plates being wall oriented at the surface thereof facing the liquid crystal means to cause said liquid crystal means to define a twisted structure in the direction perpendicular to the plates; polarizing, with a first polarizing means, light entering the cell whereby the direction of polarization of polarized light transmitted through the liquid crystal means follows the orientation of the molecules of the liquid crystal means; providing transverse to said plates the electric field across at least a portion of the liquid crystal means for changing the orientation of the liquid crystal molecules under the influence of the electrical field such that said molecules align in a direction substantially parallel to the direction of the electric field; and analyzing with a second polarizing means light transmitted through the liquid crystal means.
Claim 27
Dependent Claim
186 words
A process for the control of light transmission comprising the steps of: providing an electro-optical cell having nematic liquid crystal means of positive dielectric anisotropy disposed between a pair of spaced plates at least one of which is transparent and means for enabling an electrical field to be applied across the liquid crystal means, said plates being wall oriented at the surface thereof facing the liquid crystal means to cause said liquid crystal means to define a twisted structure in the direction perpendicular to the plates; polarizing, with a first polarizing means, light entering the cell whereby the direction of polarization of polarized light transmitted through the liquid crystal means follows the orientation of the molecules of the liquid crystal means; providing transverse to said plates the electric field across at least a portion of the liquid crystal means for changing the orientation of the liquid crystal molecules under the influence of the electrical field such that said molecules align in a direction substantially parallel to the direction of the electric field; and analyzing with a second polarizing means light transmitted through the liquid crystal means.
Claim 28
Dependent Claim
13 words
A process according to claim 24 wherein said field is a DC field.
Claim 29
Dependent Claim
13 words
A process according to claim 24 wherein said field is an alternating field.
Claim 30
Dependent Claim
27 words
A process according to claim 24 including rubbing each of said facing surfaces to derive a surface state oriented in a non-parallel direction relative to one another.
Claim 31
Dependent Claim
43 words
A process according to claim 27 wherein the surface state of each facing surface is oriented in a direction which is perpendicular to the direction of orientation of the other, such that the plane of polarization of the light is rotated through 90*.
Claim 32
Dependent Claim
19 words
A process according to claim 24 wherein said liquid crystal means consists essentially of a nematic liquid crystal material.
Claim 33
Dependent Claim
16 words
A process according to claim 29 wherein said liquid crystal means is nematic at room temperature.
Claim 34
Independent Claim
241 words
A method for controlling light transmission comprising: providing an optical cell having a pair of spaced plates, at least one of which is transparent, nematic liquid crystal means of positive dielectric anisotropy disposed between said plates and means for enabling an electrical field to be applied across the liquid crystal means, the surfaces of the plates facing the liquid crystal means each having a sUrface state oriented in a non-parallel direction relative to one another, the surface state of the facing surfaces exerting an orienting influence on the molecules of the liquid crystal means such that the molecules define a structure which rotates the plane of polarization of substantially all of the light passing through the liquid crystal means in the absence of the electric field; polarizing, with a first polarizing means, light entering the cell whereby the direction of polarization of polarized light passing through the liquid crystal means follows the orientation of the molecules of the liquid crystal means; providing transverse to said plates the electric field across at least a portion of the liquid crystal means for changing the orientation of the liquid crystal molecules which are under the influence of the electrical field such that said molecules align in a direction substantially parallel to the direction of the electric field, and light passing through said portion follows the orientation of said influenced molecules; and analyzing with a second polarizing means light transmitted through the liquid crystal means.
Claim 35
Independent Claim
241 words
A method for controlling light transmission comprising: providing an optical cell having a pair of spaced plates, at least one of which is transparent, nematic liquid crystal means of positive dielectric anisotropy disposed between said plates and means for enabling an electrical field to be applied across the liquid crystal means, the surfaces of the plates facing the liquid crystal means each having a sUrface state oriented in a non-parallel direction relative to one another, the surface state of the facing surfaces exerting an orienting influence on the molecules of the liquid crystal means such that the molecules define a structure which rotates the plane of polarization of substantially all of the light passing through the liquid crystal means in the absence of the electric field; polarizing, with a first polarizing means, light entering the cell whereby the direction of polarization of polarized light passing through the liquid crystal means follows the orientation of the molecules of the liquid crystal means; providing transverse to said plates the electric field across at least a portion of the liquid crystal means for changing the orientation of the liquid crystal molecules which are under the influence of the electrical field such that said molecules align in a direction substantially parallel to the direction of the electric field, and light passing through said portion follows the orientation of said influenced molecules; and analyzing with a second polarizing means light transmitted through the liquid crystal means.
Claim 36
Dependent Claim
43 words
A method according to claim 31 wherein the surface state of each facing surface is oriented in a direction which is perpendicular to the direction of orientation of the other, such that the plane of polarization of the light is rotated through 90*.
Claim 37
Dependent Claim
180 words
An optical device comprising: a. optical cell means comprising a pair of spaced plates, at least one of which is transparent and a substance disposed between said plates which passes substantially all light incident on the substance and which consists essentially of a nematic liquid crystal material of positive dielectric anisotropy, said substance having a molecular orientation defining a structure which optically rotates substantially all light passing through the substance, the surface of each plate facing the substance having a surface state oriented in a non-parallel direction relative to one another, for causing the molecules of the substance to become oriented into said structure; b. means in operative contact with the substance for electrically controlling the molecular orientation of at least a portion of the substance effective to terminate the optical rotation of the light passing through the electrically controlled portion of the substance; c. means proximate said at least one transparent plate for polarizing the light received by said transparent plate; and d. polarizing means proximate the other of said plates for analyzing the light passing through the substance.
Claim 38
Dependent Claim
180 words
An optical device comprising: a. optical cell means comprising a pair of spaced plates, at least one of which is transparent and a substance disposed between said plates which passes substantially all light incident on the substance and which consists essentially of a nematic liquid crystal material of positive dielectric anisotropy, said substance having a molecular orientation defining a structure which optically rotates substantially all light passing through the substance, the surface of each plate facing the substance having a surface state oriented in a non-parallel direction relative to one another, for causing the molecules of the substance to become oriented into said structure; b. means in operative contact with the substance for electrically controlling the molecular orientation of at least a portion of the substance effective to terminate the optical rotation of the light passing through the electrically controlled portion of the substance; c. means proximate said at least one transparent plate for polarizing the light received by said transparent plate; and d. polarizing means proximate the other of said plates for analyzing the light passing through the substance.
Claim 39
Dependent Claim
20 words
An optical device according to claim 33 wherein the liquid crystal materials is in its nematic phase at room temperature.
Claim 40
Dependent Claim
47 words
An optical device according to claim 34 wherein said means for electrically controlling the molecular orientation of said portion of the substance includes conductive means comprising a transparent conductive material on the facing surfaces of said plates and connecting leads for applying a voltage to the plates.
Claim 41
Dependent Claim
26 words
An optical device according to claim 34 wherein said facing surfaces are unidirectionally rubbed in non-parallel directions relative to one another to provide said surface state.
Claim 42
Dependent Claim
27 words
An optical device according to claim 36 wherein said facing surface is rubbed in a direction which is perpendicular to the direction of rubbing of the other.
Claim 43
Dependent Claim
24 words
An optical device according to claim 33 wherein the liquid crystal material is nematic in the temperature range of at least -10*C to 70*C.
Claim 44
Dependent Claim
167 words
An optical device for controlling the transmission of light comprising: a. a substance consisting essentially of a nematic liquid crystal material having positive dielectric anisotropy, b. means confining said liquid crystal material whereby said confining means and said liquid crystal material form an optical cell which passes through the liquid crystal material substantially all light incident on the liquid crystal material, c. said liquid crystal material having a twisted molecular structure, d. said confining means being transparent on at least one side of said cell and being prepared at the surfaces facing the liquid crystal material to cause said liquid crystal material to define said twisted structure wherein the twist extends in a direction transverse to said at least one side of said cell, e. light polarizing means disposed in front of and behind the liquid crystal material in the path of light transmitted through the liquid crystal material, and f. means for applying an electrical field to said liquid crystal material to control its twisted structure.
Claim 45
Dependent Claim
167 words
An optical device for controlling the transmission of light comprising: a. a substance consisting essentially of a nematic liquid crystal material having positive dielectric anisotropy, b. means confining said liquid crystal material whereby said confining means and said liquid crystal material form an optical cell which passes through the liquid crystal material substantially all light incident on the liquid crystal material, c. said liquid crystal material having a twisted molecular structure, d. said confining means being transparent on at least one side of said cell and being prepared at the surfaces facing the liquid crystal material to cause said liquid crystal material to define said twisted structure wherein the twist extends in a direction transverse to said at least one side of said cell, e. light polarizing means disposed in front of and behind the liquid crystal material in the path of light transmitted through the liquid crystal material, and f. means for applying an electrical field to said liquid crystal material to control its twisted structure.
Claim 46
Dependent Claim
26 words
An optical device according to claim 39 wherein said liquid crystal material has a nematic phase in the temperature range of at least -10*C to 70*C.
Claim 47
Dependent Claim
72 words
A device according to claim 40 wherein said means for applying an electrical field includes conductive material on said facing surfaces and means for applying a voltage to the conductive material and establishing said electrical field across at least a portion of said liquid crystal means whereby the molecules of the liquid crystal means under the influence of the electrical field align substantially parallel to the direction of the applied electrical field.
Claim 48
Independent Claim
255 words
A method of controlling the transmission of light comprising the steps of: a. confining a nematic liquid crystal material having positive dielectric anisotropy between a pair of facing wall surfaces at least one of which walls is transparent, b. establishing a first condition of light transmission in the liquid crystal material by preparing said facing wall surfaces to provide a surface state oriented in non-parallel directions relative to one another for causing the liquid crystal material to assume a molecular orientation effective to rotate the plane of polarized light through a predetermined angle, c. introducing polarized light into the liquid crystal material through said at least one transparent wall and in said first condition rotating the plane of polarization of the light through said predetermined angle as it passes through the liquid crystal material, d. directing the rotated light to a polarizer having a plane of polarization in predetermined relationship with the plane of polarization of the light incident on the liquid crystal material, e. electrically establishing a second condition in at least a portion of the liquid crystal material such that the plane of polarization of light emitted therefrom is transverse to the plane of polarization of emitted light from the liquid crystal material in said first condition, and f. transmitting light from said polarizer when said portion of the liquid crystal material is in one of said conditions and substantially blocking the transmission of light by said polarizer when said portion of the liquid crystal material is in the other of said conditions.
Claim 49
Independent Claim
255 words
A method of controlling the transmission of light comprising the steps of: a. confining a nematic liquid crystal material having positive dielectric anisotropy between a pair of facing wall surfaces at least one of which walls is transparent, b. establishing a first condition of light transmission in the liquid crystal material by preparing said facing wall surfaces to provide a surface state oriented in non-parallel directions relative to one another for causing the liquid crystal material to assume a molecular orientation effective to rotate the plane of polarized light through a predetermined angle, c. introducing polarized light into the liquid crystal material through said at least one transparent wall and in said first condition rotating the plane of polarization of the light through said predetermined angle as it passes through the liquid crystal material, d. directing the rotated light to a polarizer having a plane of polarization in predetermined relationship with the plane of polarization of the light incident on the liquid crystal material, e. electrically establishing a second condition in at least a portion of the liquid crystal material such that the plane of polarization of light emitted therefrom is transverse to the plane of polarization of emitted light from the liquid crystal material in said first condition, and f. transmitting light from said polarizer when said portion of the liquid crystal material is in one of said conditions and substantially blocking the transmission of light by said polarizer when said portion of the liquid crystal material is in the other of said conditions.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |