US4088400A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display devices
Assignee: Thales SA
•
Filing: 1973-12-21
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Granted: 1978-05-09
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Expires: 1993-12-21
Abstract
Abstract An improvement in electro-optical display devices utilizing polarized light is disclosed, in which the linearly polarized light emerging from the display device is picked up by a diffuser and reaches the observer eyes after passing through a linear polarizer. The contrast is thus enhanced and the display can be used in presence of strong ambient lighting. The contrast can be still further improved by arranging at either side of the diffuser two suitably oriented quarter-wave plates.
Inventors
- 👤 Georges Assouline
- 👤 Michel Hareng
- 👤 Michel Roncillat
- 👤 Eugene Leiba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:34
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133528; G02F1/133553; G02F1/1336; G02F1/13363; G02F1/133638; G02F2413/00; G02F2413/02; G02F2413/07
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
45 words
A display device comprising means for producing a parallel beam of linearly polarized light, and successively positioned for receiving said light; electro-optical modulating means, first linear polarizer means having a first polarization direction, diffuser means and second linear polarizer means having a second polarization direction.
Claim 2
Dependent Claim
45 words
A display device comprising means for producing a parallel beam of linearly polarized light, and successively positioned for receiving said light; electro-optical modulating means, first linear polarizer means having a first polarization direction, diffuser means and second linear polarizer means having a second polarization direction.
Claim 3
Dependent Claim
17 words
A device as claimed in claim 1, wherein said first and second polarization directions are mutually parallel.
Claim 4
Dependent Claim
26 words
A device as claimed in claim 1, wherein that face of said second linear polarizer means which is opposite said diffuser means, has an anti-reflection coating.
Claim 5
Dependent Claim
40 words
A device as claimed in claim 1, wherein first and second optical phase-shift means are positioned for receiving said light respectively between said first polarizer means and said diffuser means and between said diffuser means and said second polarizer means.
Claim 6
Dependent Claim
77 words
A device as claimed in claim 4, wherein each said first and second optical phase-shift means respectively introduce, between two mutually perpendicular preferred directions of vibration, an optical phase-shift equal to an odd multiple of a quarter wave length; said wave length being the mean wave length of said polarized light; said two preferred directions of said first and of said second phase-shift means making an angle of 45° respectively with said first and second polarization directions.
Claim 7
Dependent Claim
40 words
A device as claimed in claim 1, wherein optical projection means are arranged between said modulator means and said diffuser means and facing said first polarizer means to project the image of said modulating means on to said diffuser means.
References Cited (Backward Citations)
US3067413A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |