US4815825A
Expired / Lapsed
US
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Liquid crystal display device
Assignee: Hitachi Ltd
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Filing: 1986-12-17
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Granted: 1989-03-28
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Expires: 2006-12-17
Abstract
Abstract A liquid crystal display device including a nematic liquid crystal composition having a twist angle of 160 DEG to 260 DEG of liquid crystal molecules and at least one compound of the formula: <IMAGE> (m, n=1-7) further improved in time-multiplexability and display quality.
Inventors
- 👤 Tamihito Nakagomi
- 👤 Yasuhiko Kando
- 👤 Shinji Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:40
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/30; C09K19/3001; C09K19/02; C09K19/0208; C09K19/42
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
245 words
A liquid crystal display device comprising a pair of electrode substrates placed oppositely and interposing there-between a nematic liquid crystal composition containing chiral material and having positive dielectric anisotropy and a helical structure of liquid crystal molecules twisted with respect to the thickness direction, and a pair of polarizers placed outside the electrode substrates, said device being characterized in that the liquid crystal molecules have a helical structure twisted at 160° to 260° with respect to the thickness direction, the polarization axes or absorption axes of the polarizers are inclined at an angle of 20° to 70° with respect to the direction of the major axes of the liquid crystal molecules adjacent to the electrode substrates and a product of Δn·d wherein Δn is reflective index anisotropy of the liquid crystals and d is a thickness of the liquid crystal layer in terms of μm being 0.7 to 1.2 μm, and said nematic liquid crystal composition comprises 5 to 60% by weight of at least one compound of the formula: ##STR81## wherein m and n are independently an integer of 1 to 7, 5 to 50% by weight of at least one member selected from the group consisting of compounds of the formula: ##STR82## wherein R 1 is an alkyl group having 2 to 7 carbon atoms, and 5 to 30% by weight of at least one compound of the formula: ##STR83## wherein R 2 is an alkyl group having 2 to 8 carbon atoms.
Claim 2
Dependent Claim
245 words
A liquid crystal display device comprising a pair of electrode substrates placed oppositely and interposing there-between a nematic liquid crystal composition containing chiral material and having positive dielectric anisotropy and a helical structure of liquid crystal molecules twisted with respect to the thickness direction, and a pair of polarizers placed outside the electrode substrates, said device being characterized in that the liquid crystal molecules have a helical structure twisted at 160° to 260° with respect to the thickness direction, the polarization axes or absorption axes of the polarizers are inclined at an angle of 20° to 70° with respect to the direction of the major axes of the liquid crystal molecules adjacent to the electrode substrates and a product of Δn·d wherein Δn is reflective index anisotropy of the liquid crystals and d is a thickness of the liquid crystal layer in terms of μm being 0.7 to 1.2 μm, and said nematic liquid crystal composition comprises 5 to 60% by weight of at least one compound of the formula: ##STR81## wherein m and n are independently an integer of 1 to 7, 5 to 50% by weight of at least one member selected from the group consisting of compounds of the formula: ##STR82## wherein R 1 is an alkyl group having 2 to 7 carbon atoms, and 5 to 30% by weight of at least one compound of the formula: ##STR83## wherein R 2 is an alkyl group having 2 to 8 carbon atoms.
Claim 3
Dependent Claim
42 words
A liquid crystal display device according to claim 1, wherein the nematic liquid crystal composition comprises 10 to 60% by weight of compounds of the formula (I) having an average value of a total of m plus n being 6 or less.
Claim 4
Dependent Claim
100 words
A liquid crystal display device according to claim 1, wherein the nematic liquid crystal composition further comprises at least one member selected from the group consisting of compounds of the formula: ##STR84## wherein R 13 is an alkyl group having 2 to 5 carbon atoms, in an amount of 20% by weight or less, compounds of the formula: ##STR85## wherein R 14 is an alkyl group having 2 to 6 carbon atoms in an amount of 20% by weight or less, and compounds of the formula: ##STR86## wherein R 18 is an alkyl group having 2 to 7 carbon atoms.
Claim 5
Dependent Claim
90 words
A liquid crystal display device according to claim 1, wherein the nematic liquid crystal composition further comprises at least one member selected from the group consisting of compounds of the formula: ##STR87## wherein R 5 and R 6 are independently an alkyl group having 2 to 6 carbon atoms, in an amount of 25% by weight or less, and compounds of the formula: ##STR88## wherein R 10 and R 11 are independently an alkyl group having 2 to 5 carbon atoms, in an amount of 15% by weight or less.
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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) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |