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US5278684A
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Parallel aligned chiral nematic liquid crystal display element
Assignee: Fujitsu Ltd
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Filing: 1992-08-17
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Granted: 1994-01-11
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Expires: 2012-08-17
Abstract
Abstract A liquid crystal display element comprising a liquid crystal composition having an optically active compound as at least one constituent and showing a cholesteric phase in a bulk state, wherein the liquid crystal composition is arranged between substrates, at least one of which is provided with a transparent electrode, so that long axes of individual liquid crystal molecules are in parallel to one another and are oriented in the same direction as the surfaces of the substrates, and the long axes of the molecules are uniformly aligned in parallel, vertically or inclined to the surfaces of the substrates, wherein the gap d (μm) between the substrates and the size p (μm) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationships: d/p≧ 1.
Inventors
- 👤 Akihiro Mochizuki
- 👤 Fumiyo Onda
- 👤 Toshiaki Yoshihara
- 👤 Masayuki Iwasaki
- 👤 Yasuo Yamagishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:44
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/13306; G02F1/137; G02F1/139; G02F1/1393
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
158 words
A liquid crystal display element comprising: a layer of cholesteric phase liquid crystal composition having an optically active compound as at least one constituent and showing a helical structure in a bulk state, wherein the liquid crystal composition is arranged between substrates, at least one of which is provided with a transparent electrode; and orienting and aligning means for orienting long axes of individual liquid crystal molecules in parallel to one another and in the same direction to the surfaces of the substrate, and for uniformly aligning the long axes of the molecules in parallel, vertically or inclined to the surfaces of the substrates both when an electric field is applied and when an electric field in not applied, wherein the gap d (μm) between the substrates and the size p (μm) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationship: d/p≧1.
Claim 2
Dependent Claim
158 words
A liquid crystal display element comprising: a layer of cholesteric phase liquid crystal composition having an optically active compound as at least one constituent and showing a helical structure in a bulk state, wherein the liquid crystal composition is arranged between substrates, at least one of which is provided with a transparent electrode; and orienting and aligning means for orienting long axes of individual liquid crystal molecules in parallel to one another and in the same direction to the surfaces of the substrate, and for uniformly aligning the long axes of the molecules in parallel, vertically or inclined to the surfaces of the substrates both when an electric field is applied and when an electric field in not applied, wherein the gap d (μm) between the substrates and the size p (μm) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationship: d/p≧1.
Claim 3
Dependent Claim
50 words
A liquid crystal display element as set forth in claim 1, wherein the gap d (μm) between the substrates and the size p (μm) of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied satisfy the following relationships: 5≧d/p≧1.
Claim 4
Dependent Claim
64 words
A liquid crystal display element as set forth in claim 1, wherein the cholesteric phase liquid crystal is a cholesteric liquid crystal, a chiralnematic liquid crystal or a mixture of a nematic liquid crystal and a cholesteric liquid crystal or chiralnematic liquid crystal or a mixture of a nematic liquid crystal and an optically active substance having a good compatibility with a liquid crystal.
Claim 5
Dependent Claim
46 words
A liquid crystal display element as set forth in claim 3, wherein the content of the cholesteric liquid crystal or chiralnematic liquid crystal in the mixture of the nematic liquid crystal and the cholesteric liquid crystal or chiralnematic liquid crystal is at least 3% by weight.
Claim 6
Dependent Claim
38 words
A liquid crystal display element as set forth in claim 3, wherein the content of the optically active substance in the mixture of the nematic liquid crystal and the optically active substance is at least 3% by weight.
Claim 7
Dependent Claim
20 words
A liquid crystal display element as set forth in claim 5, wherein the optically active substance is l-menthol or l-adrenaline.
Claim 8
Dependent Claim
40 words
A liquid crystal display element as set forth in claim 1, wherein the size of the helical pitch shown by the cholesteric phase liquid crystal at room temperature when an electric field is not applied is smaller than 1.5 μm.
Claim 9
Dependent Claim
20 words
A liquid crystal display element as set forth in claim 1 further comprising two polarizing films attached to the substrates.
Claim 10
Dependent Claim
50 words
A liquid crystal display element as set forth i claim 1, wherein a thickness of the layer of the cholesteric phase liquid crystal undergoing regulation of alignment by interface mutual action with the orienting and aligning means is at least 1/3 of the entire thickness of the liquid crystal layer.
Claim 11
Dependent Claim
24 words
A liquid crystal display element as set forth in claim 1, wherein the thickness of the liquid crystal layer is 1 to 5 μm.
Claim 12
Dependent Claim
140 words
A liquid crystal display element as set forth in claim 1, wherein the liquid crystal display element indicates a double hysteresis loop, when drived in a method which comprises the steps of (1) applying to all electrodes a voltage V H having a positive polarity necessary for reducing the light transmission to a saturation value, (2) applying to selected points a voltage V L having a positive polarity lower than said voltage V H but higher than a voltage just before the light transmission is changed to a low value from a high value, (3) applying a voltage having a negative polarity lower than -V H to non-selected points, and (4) subsequent to the step (3), applying a voltage lower than V H but higher than V L to the non-elected points and retaining said voltage at the non-selected points.
Claim 13
Dependent Claim
27 words
A liquid crystal display element as set forth in claim 1, wherein a dielectric constant ε of the liquid crystal composition is almost constant until 3 KHz.
Claim 14
Dependent Claim
22 words
A liquid crystal display element as set forth in claim 1, wherein an optical switching can be done with no ε change.
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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) | 1997-01-10 | 1997-07-12 | 1998-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-10 | 2001-07-12 | 2002-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-10 | 2005-07-12 | 2006-01-11 | $7700.00 | Window Closed / Lapsed |