US5196953A
Expired / Lapsed
US
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Compensator for liquid crystal display, having two types of layers with different refractive indices alternating
Assignee: Teledyne Scientific and Imaging LLC
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Filing: 1991-11-01
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Granted: 1993-03-23
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Expires: 2011-11-01
Abstract
Abstract A liquid crystal display includes a polarizer layer, an analyzer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer, a first electrode proximate to a first major surface of the liquid crystal layer, and a second electrode proximate to a second major surface of the liquid crystal layer. The first and second electrodes are adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential. A multilayer thin film compensator is disposed between the polarizer layer and the analyzer layer, the multilayer compensator including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness. The values of the first and second refractive indices and thicknesses are such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Inventors
- 👤 Pochi A. Yeh
- 👤 William J. Gunning
- 👤 John P. Eblen, Jr.
- 👤 Mohsen Khoshnevisan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:08
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/133634; G02F2413/00; G02F2413/01; G02F2413/13
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
176 words
A liquid crystal display, comprising: a polarizer layer; an analyzer layer; a liquid crystal layer disposed between the polarizer layer and the analyzer layer; a first electrode proximate to a first major surface of the liquid crystal layer; a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential; and a multilayer thin film compensator disposed between the polarizer layer and the analyzer layer, including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 2
Dependent Claim
176 words
A liquid crystal display, comprising: a polarizer layer; an analyzer layer; a liquid crystal layer disposed between the polarizer layer and the analyzer layer; a first electrode proximate to a first major surface of the liquid crystal layer; a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential; and a multilayer thin film compensator disposed between the polarizer layer and the analyzer layer, including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 3
Dependent Claim
44 words
The display of claim 1, wherein: the liquid crystal layer has a thickness d L and a birefringence Δn L ; the multilayer has a thickness d C and a birefringence Δn C ; and |Δn L |d L =|Δn C |d C .
Claim 4
Dependent Claim
62 words
The display of claim 2, wherein: the liquid crystal layer has an ordinary index of refraction n oL and an extraordinary index of refraction n eL ; the multilayer has an ordinary index of refraction n oC and an extraordinary index of refraction n eC ; n eC =n oL ; n oC =n eL ; and d L =d C .
Claim 5
Dependent Claim
77 words
The display of claim 2, wherein the equivalent refractive indices of the multilayer satisfy the relationships: ##EQU4## where n o is the equivalent ordinary refractive index of the multilayer, n e is the equivalent extraordinary refractive index of the multilayer, n 1 is the first refractive index, n 2 is the second refractive index, d 1 is the first thickness, d 2 is the second thickness, and Λ=d 1 +d 2 is the period of the multilayer.
Claim 6
Dependent Claim
182 words
A liquid crystal display of the type including a polarizer layer, an analyzer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer, a first electrode proximate to a first major surface of the liquid crystal layer, and a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential; the improvement comprising: a multilayer thin film compensator disposed between the polarizer layer and the analyzer layer, including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 7
Dependent Claim
182 words
A liquid crystal display of the type including a polarizer layer, an analyzer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer, a first electrode proximate to a first major surface of the liquid crystal layer, and a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential; the improvement comprising: a multilayer thin film compensator disposed between the polarizer layer and the analyzer layer, including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 8
Dependent Claim
44 words
The display of claim 5, wherein: the liquid crystal layer has a thickness d L and a birefringence Δn L ; the multilayer has a thickness d C and a birefringence Δn C ; and |Δn L |d L =|Δn C |d C .
Claim 9
Dependent Claim
62 words
The display of claim 6, wherein: the liquid crystal layer has an ordinary index of refraction n oL and an extraordinary index of refraction n eL ; the multilayer has an ordinary index of refraction n oC and an extraordinary index of refraction n eC ; n eC =n oL ; n oC =n eL ; and d L =d C .
Claim 10
Dependent Claim
77 words
The display of claim 6, wherein the equivalent refractive indices of the multilayer satisfy the relationships: ##EQU5## where n o is the equivalent ordinary refractive index of the multilayer, n e is the equivalent extraordinary refractive index of the multilayer, n l is the first refractive index, n 2 is the second refractive index, d 1 is the first thickness, d 2 is the second thickness, and Λ=d 1 +d 2 is the period of the multilayer.
Claim 11
Independent Claim
195 words
A method of compensating for phase retardation in a liquid crystal display of the type including a polarizer layer, an analyzer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer, a first electrode proximate to a first major surface of the liquid crystal layer, and a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential, the method comprising the step of: placing a multilayer thin film compensator between the polarizer layer and the analyzer layer, the multilayer including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 12
Independent Claim
195 words
A method of compensating for phase retardation in a liquid crystal display of the type including a polarizer layer, an analyzer layer, a liquid crystal layer disposed between the polarizer layer and the analyzer layer, a first electrode proximate to a first major surface of the liquid crystal layer, and a second electrode proximate to a second major surface of the liquid crystal layer, the first and second electrodes being adapted to apply a voltage across the liquid crystal layer when the electrodes are connected to a source of electrical potential, the method comprising the step of: placing a multilayer thin film compensator between the polarizer layer and the analyzer layer, the multilayer including a first plurality of layers, each having a first refractive index and a first thickness, alternating with a second plurality of layers, each having a second refractive index and a second thickness, the values of the first and second refractive indices and thicknesses being such that the phase retardation of the multilayer is equal in magnitude but opposite in sign to the phase retardation of the liquid crystal layer in its homeotropically aligned state over a predetermined range of viewing angles.
Claim 13
Dependent Claim
44 words
The method of claim 9, wherein: the liquid crystal layer has a thickness d L and a birefringence Δn L ; the multilayer has a thickness d C and a birefringence Δn C ; and |Δn L |d L =|Δn C |d C .
Claim 14
Dependent Claim
62 words
The display of claim 10, wherein: the liquid crystal layer has an ordinary index of refraction n oL and an extraordinary index of refraction n eL ; the multilayer has an ordinary index of refraction n oC and an extraordinary index of refraction n eC ; n eC =n oL ; n oC =n eL ; and d L =d C .
Claim 15
Dependent Claim
85 words
The method of claim 10, wherein the values of the first and second refractive indices and thicknesses are further selected to satisfy the relationships: ##EQU6## where n o is the equivalent ordinary refractive index of the multilayer, n e is the equivalent extraordinary refractive index of the multilayer, n 1 is the first refractive index, n 2 is the second refractive index, d 1 is the first thickness, d 2 is the second thickness, and Λ=d 1 +d 2 is the period of the multilayer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |