Patent US3097231A successfully refreshed from Google Patents.
US4032218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for the production and modulation of monochromatic light
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1975-05-27
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Granted: 1977-06-28
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Expires: 1995-05-27
Abstract
Abstract An improved apparatus is disclosed for producing and modulating monochromatic light and is characterized by a bright, high contrast display surface. The apparatus includes a linear polarizer positioned between a light source and a liquid crystal cell, and utilizes, as a reflector, a substance with a helical structure. A circular polarizer is positioned between the liquid crystal cell and the reflector.
Inventors
- 👤 Terry J. Scheffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:18
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/42; C09K19/50; G; G02; G02B; G02B5/00; G02B5/30; G02B5/3016; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133528; G02F1/133536; G02F1/133553; G02F1/137; G02F1/139; G02F1/1396; G02F1/13363; G02F1/133638; G02F2201/00; G02F2201/08; G02F2201/34; G02F2201/343
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
174 words
In a device for the production and modulation of colored light from light emanating from a suitable source by means of a liquid-crystal electro-optical cell coated with electrodes and combined with a polarizing arrangement and a reflector, the liquid crystal exhibiting a helically twisted structure with a twisting angle of at least approximately 90° along the direction normal to the film-like electrodes, the improvement comprising: a linear polarizer positioned between said light source and said liquid-crystal cell and acting as said polarizing arrangement, said reflector formed of a substance with a helicoidal structure which reflects colored circularly polarized light of one handedness and transmits colored circularly polarized light of the opposite handedness and a light absorbing material directly adjacent said substance; and, a circular polarizer formed of a quarter-wave plate positioned between said liquid-crystal cell and said reflector. said quarter-wave plate directly adjacent to said liquid-crystal cell on the side facing said reflector and, said substance with a helicoidal structure placed directly adjacent to said quarter-wave plate to minimize undesirable effects due to parallax.
Claim 2
Dependent Claim
174 words
In a device for the production and modulation of colored light from light emanating from a suitable source by means of a liquid-crystal electro-optical cell coated with electrodes and combined with a polarizing arrangement and a reflector, the liquid crystal exhibiting a helically twisted structure with a twisting angle of at least approximately 90° along the direction normal to the film-like electrodes, the improvement comprising: a linear polarizer positioned between said light source and said liquid-crystal cell and acting as said polarizing arrangement, said reflector formed of a substance with a helicoidal structure which reflects colored circularly polarized light of one handedness and transmits colored circularly polarized light of the opposite handedness and a light absorbing material directly adjacent said substance; and, a circular polarizer formed of a quarter-wave plate positioned between said liquid-crystal cell and said reflector. said quarter-wave plate directly adjacent to said liquid-crystal cell on the side facing said reflector and, said substance with a helicoidal structure placed directly adjacent to said quarter-wave plate to minimize undesirable effects due to parallax.
Claim 3
Dependent Claim
43 words
An improved device as in claim 15, wherein: the preferred direction of said coated electrode which is positioned adjacent to said quarter-wave plate and the optic axis of the latter are rotated 45° from one another about the normal to said quarter-wave plate.
Claim 4
Dependent Claim
17 words
An improved device as in claim 1, wherein: said reflector with a helicoidal structure is a liquid-crystal.
Claim 5
Dependent Claim
14 words
An improved device as in claim 3, wherein: said reflector liquid crystal is cholesteric.
Claim 6
Dependent Claim
16 words
An improved device as in claim 4, wherein: said reflector liquid crystal is cholesteryl oleyl carbonate.
Claim 7
Dependent Claim
17 words
An improved device as in claim 4, wherein: said reflector liquid-crystal is a mixture of cholesteric substances.
Claim 8
Dependent Claim
20 words
An improved device as in claim 4, wherein: said reflector liquid crystal comprises a mixture of nematic and cholesteric substances.
Claim 9
Dependent Claim
27 words
An improved device as in claim 7, wherein: said reflector liquid crystal has approximately the composition 48% by weight cholesteryl oleyl carbonate and 52% by weight n-(p-methoxybenzylidine)-p-n-butylanilin.
Claim 10
Dependent Claim
27 words
An improved device as in claim 7, wherein: said reflector liquid crystal has approximately the composition 53% by weight cholesteryl oleyl carbonate and 47% by weight n-(p-methoxybenzylidine)-p-n-butylanilin.
Claim 11
Dependent Claim
27 words
An improved device as in claim 7, wherein: said reflector liquid crystal has approximately the composition 58% by weight cholesteryl oleyl carbonate and 42% by weight n-(p-methoxybenzylidine)-p-n-butylanilin.
Claim 12
Dependent Claim
20 words
An improved device as in claim 3, wherein: said reflector liquid crystal is in the form of small, encapsulated droplets.
Claim 13
Dependent Claim
18 words
An improved device as in claim 3, wherein: said reflector liquid crystal is imbedded between two polymer films.
References Cited (Backward Citations)
US3836230A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |