US5212819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal display device with particular angle between optical axis of optically anisotropic material and observation direction
Assignee: Seiko Epson Corp
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Filing: 1991-04-09
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Granted: 1993-05-18
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Expires: 2011-04-09
Abstract
Abstract A super twisted nematic liquid crystal display device includes a liquid crystal cell, upper and lower polarizing plates, and at least one phase difference plate between the polarizing plates. The angle between the direction of the optical axis of the phase difference plate and the observation direction of the device is set between about 0°-30° or 60°-90°.
Inventors
- 👤 Hiroshi Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:02
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/133528; G02F1/133531; G02F1/137; G02F1/139; G02F1/1396; G02F2202/00; G02F2202/40; G02F2413/00; G02F2413/02; G02F2413/08
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
294 words
A liquid crystal display device, comprising: a twisted nematic liquid crystal display cell including a pair of spaced apart opposed substrates with electrodes selectively disposed thereon and a twisted nematic liquid crystal material disposed in the space between the substrates; a pair of polarizing plates disposed on opposite sides of the liquid crystal cell, one of which defines a display screen; and at least one layer of an optically anisotropic substance disposed between the liquid crystal cell and one of the pair of polarizing plates; the display screen having a rear edge as viewed from a user and an observation direction which is both in the plane of the display screen and substantially perpendicular to the rear edge thereof, the observation direction being the direction of the projection in the plane of the display screen of the direction from which a user of said display device most frequently views said display screen, the device being constructed and arranged to have a viewing angle with respect to the observation direction at which the display will have acceptable contrast to accurately convey information to a user, the angle between the direction of the optical axis of the optically anisotropic substance layer and the observation direction of the display device being set at a predetermined angle to produce substantially bilateral symmetry of the contrast distribution with respect to the observation direction as the user moves in the direction of the viewing angle β between a projection of the direction of viewing by the user in the plane of the display screen and the observation direction or in the direction of the viewing angle α between the direction of viewing of the user and an axis perpendicular to the observation direction and the plane of the display screen.
Claim 2
Dependent Claim
294 words
A liquid crystal display device, comprising: a twisted nematic liquid crystal display cell including a pair of spaced apart opposed substrates with electrodes selectively disposed thereon and a twisted nematic liquid crystal material disposed in the space between the substrates; a pair of polarizing plates disposed on opposite sides of the liquid crystal cell, one of which defines a display screen; and at least one layer of an optically anisotropic substance disposed between the liquid crystal cell and one of the pair of polarizing plates; the display screen having a rear edge as viewed from a user and an observation direction which is both in the plane of the display screen and substantially perpendicular to the rear edge thereof, the observation direction being the direction of the projection in the plane of the display screen of the direction from which a user of said display device most frequently views said display screen, the device being constructed and arranged to have a viewing angle with respect to the observation direction at which the display will have acceptable contrast to accurately convey information to a user, the angle between the direction of the optical axis of the optically anisotropic substance layer and the observation direction of the display device being set at a predetermined angle to produce substantially bilateral symmetry of the contrast distribution with respect to the observation direction as the user moves in the direction of the viewing angle β between a projection of the direction of viewing by the user in the plane of the display screen and the observation direction or in the direction of the viewing angle α between the direction of viewing of the user and an axis perpendicular to the observation direction and the plane of the display screen.
Claim 3
Dependent Claim
19 words
The liquid crystal display device of claim 1, wherein the liquid crystal material is twisted at least about 120°.
Claim 4
Dependent Claim
25 words
The liquid crystal display device of claim 1, wherein the predetermined angle is between one of about 0° and 30° and about 60° and 90°.
Claim 5
Dependent Claim
24 words
The liquid crystal display device of claim 3, wherein the optically anisotropic substance layer is made of a uniaxial high molecular weight polymers sheet.
Claim 6
Dependent Claim
39 words
The liquid crystal display device of claim 4, wherein the polymer sheet is a polymer selected from the group consisting of polycarbonate, diacetyl cellulose, polyamide, polyimide, polyether sulfone, polysulfone, polyolefin, polyethylene, polyethylene terephthalate, polyvinyl alcohol, acryl, and polymethyl methacrylate.
Claim 7
Dependent Claim
13 words
The liquid crystal display device of claim 5, wherein the polymer is polycarbonate.
Claim 8
Dependent Claim
78 words
The liquid crystal display device of claim 1, wherein the device includes at least two optically anisotropic layers of uniaxial high molecular weight polymer sheets disposed between the liquid crystal cell and one of the pair of polarizing plates, and wherein the predetermined angle between the direction of the optical axis of at least one of the sheets and the display device direction of observation is between one of about 0° and 30° and about 60° and 90°.
Claim 9
Dependent Claim
90 words
The liquid crystal display device of claim 1, wherein the device includes at least one optically anisotropic substance layer between the liquid crystal cell and one of the pair of polarizing plates and at least another optically anisotropic substance layer between the liquid crystal cell and the other polarizing plate, and the angle between the direction of the optical axis of at least one of the optically anisotropic substance layers and the display device direction of observation is between one of about 0° and 30° and about 60° and 90°.
Claim 10
Dependent Claim
21 words
The liquid crystal display device of claim 8, wherein the optically anisotropic substance layers are a uniaxial high molecular weight polymer.
Claim 11
Dependent Claim
92 words
The liquid crystal display device of claim 1, wherein the device includes at least one optically anisotropic substance layer between the liquid crystal cell and one of the pair of polarizing plates and at least another optically anisotropic substance layer between the liquid crystal cell and the other polarizing plate, and the angle between the bisector of the optical axes of the two optically anisotropic sheets adjacent to the liquid crystal cell and the display device direction of observation is between one of about 0° and 30° and about 60° and 90°.
Claim 12
Dependent Claim
24 words
The liquid crystal display device of claim 10, wherein each of the optically anisotropic substrate layers is a uniaxial high molecular weight polymer layer.
Claim 13
Dependent Claim
234 words
A liquid crystal display device having a display screen with a rear edge as viewed from a user, comprising: a super twisted nematic liquid crystal cell including first and second opposed electrode substrates with a twisted nematic liquid crystal material therebetween with an angle of twist between about 180° and 260° from the first substrate to the second, the cell having an observation direction, the observation direction being a direction of the projection in the plane of the display screen of the direction from which a user of said display device most frequently views said display screen, the observation direction being both in the plane of the display screen and substantially perpendicular to the rear edge thereof; a pair of polarizing plates disposed on opposite sides of the liquid crystal cell with Θ 1 being the angle between the observation direction and the axis of polarization of the first polarizer adjacent the first substrate of the liquid crystal cell and Θ 2 being the angle between the observation direction and the axis of polarization of the other polarizer; and at least one layer of an optically anisotropic material between the liquid crystal cell and one polarizer with Θ 3 being the angle between the optical axis of the at least one layer of optically anisotropic material and the observation direction, Θ 3 between one of about 0° and 30° and about 60° and 90°.
Claim 14
Dependent Claim
234 words
A liquid crystal display device having a display screen with a rear edge as viewed from a user, comprising: a super twisted nematic liquid crystal cell including first and second opposed electrode substrates with a twisted nematic liquid crystal material therebetween with an angle of twist between about 180° and 260° from the first substrate to the second, the cell having an observation direction, the observation direction being a direction of the projection in the plane of the display screen of the direction from which a user of said display device most frequently views said display screen, the observation direction being both in the plane of the display screen and substantially perpendicular to the rear edge thereof; a pair of polarizing plates disposed on opposite sides of the liquid crystal cell with Θ 1 being the angle between the observation direction and the axis of polarization of the first polarizer adjacent the first substrate of the liquid crystal cell and Θ 2 being the angle between the observation direction and the axis of polarization of the other polarizer; and at least one layer of an optically anisotropic material between the liquid crystal cell and one polarizer with Θ 3 being the angle between the optical axis of the at least one layer of optically anisotropic material and the observation direction, Θ 3 between one of about 0° and 30° and about 60° and 90°.
Claim 15
Dependent Claim
17 words
The liquid crystal display device of claim 12, wherein Θ 1 is between about 15° and 75°.
Claim 16
Dependent Claim
17 words
The liquid crystal display device of claim 13, wherein Θ 2 is between about 0° and 45°.
Claim 17
Dependent Claim
41 words
The liquid display device of claim 13, wherein the first substrate has a rubbing direction, and an angle Θ 4 is defined between the observation direction and the rubbing direction of the first substrate and is between about 55° and 90°.
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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) | 1996-05-17 | 1996-11-16 | 1997-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-17 | 2000-11-16 | 2001-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-17 | 2004-11-16 | 2005-05-18 | $7700.00 | Window Closed / Lapsed |