US5245456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Birefringent film with nx >nz >ny, process for producing the same, retardation film, elliptically polarizing plate, and liquid crystal display
Assignee: Nitto Denko Corp
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Filing: 1991-10-23
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Granted: 1993-09-14
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Expires: 2011-10-23
Abstract
Abstract A birefringent film in which molecules oriented in a direction parallel to the film plane and molecules oriented in the direction of the thickness of the film are present in a mixed state. Also, a process for producing the birefringent film, which comprises laminating a resin film on one or both sides thereof with a shrinkable film, thereby preparing a laminate, and then heat stretching the laminate, thereby performing stretching treatment of the resin film while imparting to the resin film the ability to shrink in the direction crossing the stretching direction. A retardation film is formed by using at least one birefringent film and has refractive indexes, n x and n y , in two directions parallel to the plate plane and crossing each other at right angles and a refractive index, n z , in the direction of the thickness of the plate, said refractive indexes n x , n y , and n z satisfying the following equation: 0<(n.sub.x -n.sub.z)/(n.sub.x -n.sub.y)<1 provided that n x >n y . Also, an elliptically polarizing plate comprises a laminate of the retardation film with a polarizing plate. Additionally, a liquid crystal display comprises a liquid crystal cell and a polarizing plate disposed at least on one side of said liquid crystal cell through the retardation film.
Inventors
- 👤 Hiroyuki Yoshimi
- 👤 Tatsuki Nagatsuka
- 👤 Yasuo Fujimura
- 👤 Tatsuya Osuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:48
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3083; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/133634; G02F2413/00; G02F2413/13
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
A birefringent film formed of a single resin in which molecules oriented in a direction parallel to the film plane and molecules oriented in the direction of the thickness of the film are present in a mixed state, which birefringent film has refractive indexes, n x and n y , in two directions parallel to the film plane and crossing each other at right angles and a refractive index, n z , in the direction of the thickness of the film, wherein n x >n z >n y .
Claim 2
Dependent Claim
89 words
A birefringent film formed of a single resin in which molecules oriented in a direction parallel to the film plane and molecules oriented in the direction of the thickness of the film are present in a mixed state, which birefringent film has refractive indexes, n x and n y , in two directions parallel to the film plane and crossing each other at right angles and a refractive index, n z , in the direction of the thickness of the film, wherein n x >n z >n y .
Claim 3
Dependent Claim
20 words
A birefringent film as claimed in claim 1, wherein the film is made of a resin which is positively birefringent.
Claim 4
Dependent Claim
27 words
A birefringent film as claimed in claim 2, wherein the resin which is positively birefringent is a polycarbonate, poly(vinyl alcohol), cellulose acetate, polyester, polyacrylate, polyimide or polyolefin.
Claim 5
Dependent Claim
20 words
A birefringent film as claimed in claim 1, wherein the film is made of a resin which is negatively birefringent.
Claim 6
Dependent Claim
27 words
A birefringent film as claimed in claim 4, wherein the resin which is negatively birefringent is polystyrene, a styrene-based copolymer, poly(methyl methacrylate) or a methyl methacrylate-based copolymer.
Claim 7
Dependent Claim
82 words
A retardation film which uses at least one birefringent film as claimed in claim 1 and has refractive indexes, n x and n y , in two directions parallel to the film plane and crossing each other at right angles and a refractive index, n z , in the direction of the thickness of the film, said refractive indexes n x , n y , and n z satisfying the following equation: 0<(n.sub.x -n.sub.z)/(n.sub.x -n.sub.y)<1 provided that n x >n y .
Claim 8
Dependent Claim
33 words
A retardation film as claimed in claim 6, wherein said refractive indexes n x and n y satisfy the following equation: 100 nm<(n.sub.x -n.sub.y)d<1,000 nm wherein d is the thickness of the plate.
Claim 9
Dependent Claim
20 words
An elliptically polarizing plate comprising a laminate of the retardation film as claimed in claim 6 with a polarizing plate.
Claim 10
Dependent Claim
33 words
A liquid crystal display comprising a liquid crystal cell and a polarizing plate disposed at least on one side of said liquid crystal cell through the retardation film as claimed in claim 6.
Claim 11
Dependent Claim
89 words
A process for producing a birefringent film, which process comprises laminating a resin film on one or both sides thereof with a shrinkable film, thereby preparing a laminate, and then heat stretching the laminate, thereby performing stretching treatment of the resin film while imparting to the resin film the ability to shrink in the direction crossing the stretching direction in which molecules oriented in a direction parallel to the film plane and molecules oriented in the direction of the thickness of the film are present in a mixed state.
Claim 12
Dependent Claim
89 words
A process for producing a birefringent film, which process comprises laminating a resin film on one or both sides thereof with a shrinkable film, thereby preparing a laminate, and then heat stretching the laminate, thereby performing stretching treatment of the resin film while imparting to the resin film the ability to shrink in the direction crossing the stretching direction in which molecules oriented in a direction parallel to the film plane and molecules oriented in the direction of the thickness of the film are present in a mixed state.
Claim 13
Dependent Claim
32 words
A process as claimed in claim 10, wherein the degree of width-direction or lengthwise direction shrinkage of the shrinkable film is higher by at least 5% than that of the resin film.
References Cited (Backward Citations)
EP0112488A1
Cited
EP0297841A2
Cited
JPH0196623A
Cited
JPH0253230A
Cited
EP0367288A2
Cited
EP0382460A2
Cited
US5042924A
Cited
US5093739A
Cited
US5179456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-13 | 1997-03-15 | 1997-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-13 | 2001-03-15 | 2001-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-13 | 2005-03-15 | 2005-09-14 | $7700.00 | Window Closed / Lapsed |