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Liquid crystal display device with a birefringent compensator

Assignee: Ricoh Co Ltd
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Filing: 1990-02-05
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Granted: 1991-05-21
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Expires: 2010-02-05
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Abstract

Abstract Disclosed herein is a liquid crystal display device comprising (1) a liquid crystal cell having a structure in which liquid crystal molecules in the liquid crystal layer sandwiched between substrates are oriented substantially in parallel to the surface of the substrate and twisted at an angle of from 120° to 360° in the thickness direction of the liquid crystal layer when the voltage is not applied, (2) a pair of polarizers disposed so as to sandwich the liquid crystal cell therebetween and (3) a birefringence layer disposed between the liquid crystal layer and at least one of the polarizers. The liquid crystal display device can provide black and white display of excellent visual angle characteristic and of excellent quality. Furthermore, the maximum, minimum, and perpendicular refractive indexes, n x , n y , and n z , respectively, of the birefringence layer satisfy the following relationship: n.sub.y <n.sub.z <n.sub.x.

Inventors

  • 👤 Haruo Iimura

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 14:42
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/133634; G02F1/137; G02F1/139; G02F1/1396; G02F1/1397

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 219 words
A liquid crystal display device comprising: (1) a liquid crystal cell having a structure in which a liquid crystal layer is sandwiched between a pair of substrates each having at least one electrode, and liquid crystal molecules in said liquid crystal layer are oriented substantially in parallel to the surface of said substrate and twisted at an angle of from 120° to 360° in the thickness direction of said liquid crystal layer when the voltage is not applied, (2) a pair of polarizers disposed so as to sandwich said liquid crystal cell therebetween, and (3) a birefringence layer disposed between the liquid crystal layer and at least one of the polarizers, wherein the angle (β 1 ) of the polarized light transmission axis (P 1 ) of said polarizer adjacent to said birefringence layer formed to the maximum refractive index direction (X) in said birefringence layer face parallel to said substrate surface is in the range of from 20° to 70° (as an absolute value), and the maximum refractive index n x and minimum refractive index n y in said birefringence layer face parallel to said substrate surface, and the refractive index n Z of said birefringence layer in the direction perpendicular to said substrate surface have a relationship represented by the following formula (I): n.sub.Y <n.sub.Z <n.sub.X (I).
Claim 2
Dependent Claim 219 words
A liquid crystal display device comprising: (1) a liquid crystal cell having a structure in which a liquid crystal layer is sandwiched between a pair of substrates each having at least one electrode, and liquid crystal molecules in said liquid crystal layer are oriented substantially in parallel to the surface of said substrate and twisted at an angle of from 120° to 360° in the thickness direction of said liquid crystal layer when the voltage is not applied, (2) a pair of polarizers disposed so as to sandwich said liquid crystal cell therebetween, and (3) a birefringence layer disposed between the liquid crystal layer and at least one of the polarizers, wherein the angle (β 1 ) of the polarized light transmission axis (P 1 ) of said polarizer adjacent to said birefringence layer formed to the maximum refractive index direction (X) in said birefringence layer face parallel to said substrate surface is in the range of from 20° to 70° (as an absolute value), and the maximum refractive index n x and minimum refractive index n y in said birefringence layer face parallel to said substrate surface, and the refractive index n Z of said birefringence layer in the direction perpendicular to said substrate surface have a relationship represented by the following formula (I): n.sub.Y <n.sub.Z <n.sub.X (I).
Claim 3
Dependent Claim 34 words
A liquid crystal display device as defined in claim 1, wherein n x , n y and n z have a relationship represented by the following equation (I)': n.sub.y +1/4(n.sub.x -n.sub.y)<n.sub.z <n.sub.x -1/4(n.sub.x -n.sub.y)(I)'

References Cited (Backward Citations)

US4586790A Cited
US4813770A Cited
US4889412A Cited
US4844569A Cited
US4957349A Cited
EP0297841A2 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-05-20 1994-11-19 1995-05-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-05-20 1998-11-19 1999-05-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-05-20 2002-11-19 2003-05-21 $7700.00 Window Closed / Lapsed

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