US4544583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Birefringence-free plastics
Assignee: Bayer AG
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Filing: 1983-09-27
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Granted: 1985-10-01
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Expires: 2003-09-27
Abstract
Abstract Birefringence-free arrangement of plastic foils, characterized in that two plastic foils having a single principal optical axis, said optical axis lying within the plane of the plastic foil, are arranged parallel behind each other so that the optical axes of both plastic foils are forming an angle of 90°±7° and the material of the foils with regard to its optical properties and the thickness of the foils being selected in such a manner that the optical path differences Δn 1 D 1 for the light waves which are associated with the two main refraction indices within the first plastic foil is approximately equal to the optical path difference Δn 2 d 2 of the second plastic foil, Δn 1 , Δn 2 , being the difference of the main refraction indices in the first and second foil, respectively, and d 1 , d 2 standing for their thicknesses, and the use of said arrangement in components and devices in which polarized light is used, especially in liquid crystal displays.
Inventors
- 👤 Uwe Claussen
- 👤 Hellmut Hannes
- 👤 Hans-Leo Weber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:11
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3083; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133305; C; C09; C09K; C09K2323/00; C09K2323/05; C09K2323/06; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/31504; Y10T428/31507
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
152 words
Liquid crystal display comprising a birefringence-free arrangement of plastic foils, characterized in that two plastic foils having a single principal optical axis, said optical axis lying within the plane of the plastic foil, are arranged parallel one behind the other so that the optical axes of both plastic foils are forming an angle of 90°±7° and the material of the foil with regard to its optical properties and the thickness of the foils being selected in such a manner that the optical path differences Δn 1 d 1 for the light waves which are associated with the two main refraction indices within the first plastic foil is approximately equal to the optical path difference Δn 2 d 2 of the second foil, Δn 1 , Δn 2 being the differences of the main refraction indices in the first and second foil, respectively, and d 1 , d 2 standing for their thicknesses.
Claim 2
Dependent Claim
152 words
Liquid crystal display comprising a birefringence-free arrangement of plastic foils, characterized in that two plastic foils having a single principal optical axis, said optical axis lying within the plane of the plastic foil, are arranged parallel one behind the other so that the optical axes of both plastic foils are forming an angle of 90°±7° and the material of the foil with regard to its optical properties and the thickness of the foils being selected in such a manner that the optical path differences Δn 1 d 1 for the light waves which are associated with the two main refraction indices within the first plastic foil is approximately equal to the optical path difference Δn 2 d 2 of the second foil, Δn 1 , Δn 2 being the differences of the main refraction indices in the first and second foil, respectively, and d 1 , d 2 standing for their thicknesses.
Claim 3
Dependent Claim
28 words
Liquid crystal display according to claim 1, characterized in that both foils with regard to their optical properties consist of the same material and have the same thickness.
Claim 4
Dependent Claim
18 words
Liquid crystal display according to claim 1, characterized in that the foils are welded flatly with one another.
Claim 5
Dependent Claim
26 words
Liquid crystal display according to claim 1, characterized in that the foils are bonded flatly with one another, a two-component adhesive being used as the adhesive.
Claim 6
Dependent Claim
19 words
Arrangement according to claim 4, characterized in that the adhesive has the same refractive index as the foil material.
Claim 7
Dependent Claim
41 words
Liquid crystal display according to claim 1, characterized in that the plastic is polyaryl sulphone, polystyrene, polyvinyl chloride, polyurethane, a styrene/acrylonitrile copolymer, a polymethylpentene, a polyacrylate, a polymethacrylate, a cellulose ester or a mixture or a copolymer containing the polymers mentioned.
Claim 8
Dependent Claim
26 words
Liquid crystal display according to claim 1, characterized in that the plastic is polycarbonate or a plastics mixture containing at least 10% by weight of polycarbonate.
Claim 9
Dependent Claim
25 words
Liquid crystal display according to claim 1, characterized in that plastic foils are provided with halogenated compounds, Si-containing polymers, polyacrylates or polymethacrylates on the surface.
Claim 10
Dependent Claim
15 words
Liquid crystal display according to claim 7, characterized in that the plastic is cast polycarbonate.
Claim 11
Dependent Claim
22 words
Liquid crystal display according to claim 9, characterized in that the cast polycarbonate has a weight-average molecular weight M w of 75,000-110,000.
Claim 12
Dependent Claim
19 words
Liquid crystal display according to claim 1, in which a pleochroic dyestuff is dissolved in the liquid crystal material.
Claim 13
Dependent Claim
20 words
Liquid crystal display according to claim 8, characterized in that plastics foils are provided which are crosslinked on the surface.
References Cited (Backward Citations)
US2441049A
Cited
EP0089493A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |