US3881809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reflection system for liquid crystal displays
Assignee: F Hoffmann La Roche AG
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Filing: 1973-05-25
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Granted: 1975-05-06
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Expires: 1993-05-25
Abstract
Abstract High efficiency reflection without ghosts or distracting background images is obtained in a liquid crystal display of the polarized light shutter type through the use of a diffuse, highly efficient reflector placed behind the polarized liquid crystal cell. The diffuse reflector scatters the light at very large angles, providing a good viewing range while preserving the polarization. The result is a gain in contrast as compared to prior arrangements with an accompanying increase in the viewing angle.
Inventors
- 👤 James L Fergason
- 👤 Thomas B Harsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:00
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133553; G03; G03B; G03B9/00; G03B9/08; Y; Y10; Y10S; Y10S362/00; Y10S362/812
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A liquid crystal display comprising a layer of liquid crystal material disposed between first and second transparent parallel plates to provide a sandwich structure through which light can pass, said plates being coated on only selected areas thereof with films of transparent conductive material, means for polarizing light passing through said transparent plates and said liquid crystal layer, means for establishing a potential difference between films on the respective plates such that some areas of the sandwich structure will transmit light while others will not to thereby form an optical image, and reflector means adjacent one of said plates and adapted to reflect polarized light which has passed through the liquid crystal material back through the liquid crystal material, said reflector means comprising a third transparent plate having a diffuse surface on one side adjacent said one plate and a reflective surface on its other side.
Claim 2
Dependent Claim
146 words
A liquid crystal display comprising a layer of liquid crystal material disposed between first and second transparent parallel plates to provide a sandwich structure through which light can pass, said plates being coated on only selected areas thereof with films of transparent conductive material, means for polarizing light passing through said transparent plates and said liquid crystal layer, means for establishing a potential difference between films on the respective plates such that some areas of the sandwich structure will transmit light while others will not to thereby form an optical image, and reflector means adjacent one of said plates and adapted to reflect polarized light which has passed through the liquid crystal material back through the liquid crystal material, said reflector means comprising a third transparent plate having a diffuse surface on one side adjacent said one plate and a reflective surface on its other side.
Claim 3
Dependent Claim
25 words
The liquid crystal display of claim 1 including at least one edge lighting lamp for introducing light into the edge of said third transparent plate.
Claim 4
Dependent Claim
37 words
The liquid crystal display of claim 1 wherein said diffuse surface scatters light both as it enters the third transparent plate and as it passes out of the third transparent plate after reflection from said reflective surface.
Claim 5
Dependent Claim
15 words
The liquid crystal display of claim 1 wherein said reflective surface is a metalized surface.
Claim 6
Dependent Claim
137 words
A liquid crystal display comprising a layer of liquid crystal material disposed between first and second transparent parallel plates to provide a sandwich structure through which light can pass, said plates being coated on only selected areas thereof with films of transparent conductive material, means for polarizing light passing through said transparent plates and said liquid crystal layer, means for establishing a potential difference between films on the respective plates such that some areas of the sandwich structure will transmit light while others will not to thereby form an optical image, and reflector means adjacent one of said transparent plates adapted to reflect polarized light which has passed through the liquid crystal material back through the liquid crystal material, said reflector means including a metalized reflector and incorporating means for scattering polarized light without depolarizing the same.
Claim 7
Dependent Claim
137 words
A liquid crystal display comprising a layer of liquid crystal material disposed between first and second transparent parallel plates to provide a sandwich structure through which light can pass, said plates being coated on only selected areas thereof with films of transparent conductive material, means for polarizing light passing through said transparent plates and said liquid crystal layer, means for establishing a potential difference between films on the respective plates such that some areas of the sandwich structure will transmit light while others will not to thereby form an optical image, and reflector means adjacent one of said transparent plates adapted to reflect polarized light which has passed through the liquid crystal material back through the liquid crystal material, said reflector means including a metalized reflector and incorporating means for scattering polarized light without depolarizing the same.
Claim 8
Dependent Claim
29 words
The liquid crystal display of claim 5 wherein said reflector assembly comprises a sheet of metallic, reflecting material having a roughened surface facing said layer of liquid crystal material.
Claim 9
Dependent Claim
20 words
The liquid crystal display of claim 5 wherein said reflector assembly comprises discrete particles of metallic, reflecting material bonded together.
Claim 10
Dependent Claim
16 words
The liquid crystal display of claim 7 wherein said granules are disposed within a plastic matrix.
Claim 11
Dependent Claim
31 words
The liquid crystal display of claim 5 wherein said reflector assembly comprises a layer of metallic, reflecting material vacuum-deposited on a substrate having a roughened surface facing said liquid crystal layer.
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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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |