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US5033825A Expired / Lapsed US ⏱️ 0.0 years remaining

Ferroelectric liquid crystal display device having equalizing means

Assignee: Toshiba Corp
•
Filing: 1989-12-22
•
Granted: 1991-07-23
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Expires: 2009-12-22
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Abstract

Abstract A light crystal cell comprising a pair of substrates arranged substantially parallel and provided with electrodes on their opposite surfaces, and a ferroelectric liquid crystal composition held between these substrates, two polarizers arranged on either side of said liquid crystal cell, and an optical retardation film for equalizing the states of polarization of transmitted light that has passed through parts of said liquid crystal cell of different thickness. It is preferable that this optical retardation film is inserted between the liquid crystal cell and a polarizer. The number of optical retardation films need not however be limited to one, and several such films may be used. A polarizer and optical retardation film may also be assembled as one unit.

Inventors

  • 👤 Masahito Ishikawa
  • 👤 Tomiaki Yamamoto
  • 👤 Akio Murayama
  • 👤 Shoichi Matsumoto

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 18:37
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/137; G02F1/139; G02F1/141; G02F2202/00; G02F2202/40; G02F2413/00; G02F2413/01; G02F2413/08

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 74 words
A ferroelectric liquid crystal display device , comprising: a liquid crystal cell containing a pair of substrates arranged substantially parallel and provided with electrodes on their opposite surfaces, and a ferroelectric liquid crystal composition held between these substrates, two polarizers arranged on either side of said liquid crystal cell, and a means of equalizing the states of polarization of transmitted light that has passed through parts of said liquid crystal cell of different thickness.
Claim 2
Dependent Claim 74 words
A ferroelectric liquid crystal display device , comprising: a liquid crystal cell containing a pair of substrates arranged substantially parallel and provided with electrodes on their opposite surfaces, and a ferroelectric liquid crystal composition held between these substrates, two polarizers arranged on either side of said liquid crystal cell, and a means of equalizing the states of polarization of transmitted light that has passed through parts of said liquid crystal cell of different thickness.
Claim 3
Dependent Claim 26 words
A liquid crystal display device according to claim 1, wherein said equalization means is inserted between said liquid crystal cell and either one of said polarizers.
Claim 4
Dependent Claim 20 words
A liquid crystal display device according to claim 1 or 2, wherein said equalization means is an optical retardation film.
Claim 5
Dependent Claim 24 words
A liquid crystal display device according to claim 3, wherein the thickness of said liquid crystal cell is from 1 μm to 5 μm.
Claim 6
Dependent Claim 23 words
A liquid crystal display device according to claim 3, wherein said optical retardation film and the adjacent polarizer are assembled as one unit.

References Cited (Backward Citations)

US4941736A Cited
US4711530A Cited
EP0219480A2 Cited
US4844569A Cited
US4838663A Cited
JPS63306424A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-07-22 1995-01-21 1995-07-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-07-22 1999-01-21 1999-07-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-07-22 2003-01-21 2003-07-23 $7700.00 Window Closed / Lapsed

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