US5151804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferroelectric liquid crystal display having a spread of angles for grayscale and method of manufacture
Assignee: US Philips Corp
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Filing: 1990-06-11
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Granted: 1992-09-29
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Expires: 2010-06-11
Abstract
Abstract A liquid crystal device incorporating ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, the smectic layers exhibiting a spread of angles with respect to at least one of the supporting plates, whereby a gradual transmission/voltage characteristic is achieved. The spread of angles can be obtained by any of several techniques, such as subjecting the device to a low frequency electric field, or a local thermal, mechanical, chemical or magnetic treatment.
Inventors
- 👤 Antonius G. H. Verhulst
- 👤 Wilbert J. A. M. Hartmann
- 👤 Franciscus J. Stommels
- 👤 Ann M. M. Luyckx-Smolders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:59
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; G02F1/133; G02F1/1333; G02F1/1337; G02F1/133753; G02F1/133371; G02F1/133761; G02F1/1339; G02F1/13392; G02F2203/00; G02F2203/30
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
54 words
A liquid crystal device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission-voltage characteristic, characterized in that the smectic layers exhibit a spread of angles with respect to at least one of the supporting plates, whereby a gradual transmission/voltage characteristic is achieved.
Claim 2
Dependent Claim
54 words
A liquid crystal device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission-voltage characteristic, characterized in that the smectic layers exhibit a spread of angles with respect to at least one of the supporting plates, whereby a gradual transmission/voltage characteristic is achieved.
Claim 3
Dependent Claim
80 words
A display device as claimed in claim 1, in which there are spacers between the plates, and in which the first supporting plate comprises a system of row electrodes and the second supporting plate comprises a system of column electrodes, the areas of crossings of row and column electrodes defining pixels, characterized in that the spread of angles of the smectic layers of the ferroelectric liquid crystal medium is exhibited in at least a part of the areas defining pixels.
Claim 4
Dependent Claim
26 words
A display device as claimed in claim 1, characterized in that the transmission/voltage characteristic of the pixels, viewed normally to the plates, exhibits a transition range.
Claim 5
Dependent Claim
22 words
A display device as claimed in claim 2, characterized in that the spread of angles is substantially uniform from pixel to pixel.
Claim 6
Dependent Claim
30 words
A display device as claimed in claim 2, characterized in that at least one of the electrodes has a spread in the degree of the surface roughness of each pixel.
Claim 7
Dependent Claim
25 words
A device as claimed in claim 3 characterized in that the width of the transition range in the transmission/voltage characteristic is at least 0.5 Volt.
Claim 8
Dependent Claim
19 words
A display device as claimed in claim 2, characterized in that there are at least 10 spacers per pixel.
Claim 9
Dependent Claim
17 words
A display device as claimed in claim 7, characterized in that the spacers are distributed substantially uniformly.
Claim 10
Dependent Claim
22 words
A display device as claimed in claim 3, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 11
Dependent Claim
26 words
A display device as claimed in claim 2, characterized in that the transmission/voltage characteristic of the pixels, viewed normally to the plates, exhibits a transition range.
Claim 12
Dependent Claim
22 words
A display device as claimed in claim 3, characterized in that the spread of angles is substantially uniform from pixel to pixel.
Claim 13
Dependent Claim
30 words
A display device as claimed in claim 3 characterized in that at least one of the electrodes has a spread in the degree of the surface roughness of each pixel.
Claim 14
Dependent Claim
30 words
A display device as claimed in claim 4 characterized in that at least one of the electrodes has a spread in the degree of the surface roughness of each pixel.
Claim 15
Dependent Claim
25 words
A device as claimed in claim 4 characterized in that the width of the transition range in the transmission/voltage characteristic is at least 0.5 Volt.
Claim 16
Dependent Claim
25 words
A device as claimed in claim 5 characterized in that the width of the transition range in the transmission/voltage characteristic is at least 0.5 Volt.
Claim 17
Dependent Claim
18 words
A display device as claimed in claim 3, characterized in that there are least 10 spacers per pixel.
Claim 18
Dependent Claim
18 words
A display device as claimed in claim 4, characterized in that there are least 10 spacers per pixel.
Claim 19
Dependent Claim
19 words
A display device as claimed in claim 5, characterized in that there are at least 10 spacers per pixel.
Claim 20
Dependent Claim
19 words
A display device as claimed in claim 6, characterized in that there are at least 10 spacers per pixel.
Claim 21
Dependent Claim
22 words
A display device as claimed in claim 4, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 22
Dependent Claim
22 words
A display device as claimed in claim 5, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 23
Dependent Claim
22 words
A display device as claimed in claim 6, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 24
Dependent Claim
22 words
A display device as claimed in claim 7, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 25
Dependent Claim
22 words
A display device as claimed in claim 8, characterized in that a desired transmission state is reached from an extreme transmission state.
Claim 26
Independent Claim
78 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission/voltage characteristic, characterized in that the device is subjected to at least one low-frequency electric field treatment at a low field strength, resulting in a spread of angles of the smectic layers with respect to at least one of the supporting plates, whereby a gradual transmission/voltage characteristic is achieved.
Claim 27
Independent Claim
78 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission/voltage characteristic, characterized in that the device is subjected to at least one low-frequency electric field treatment at a low field strength, resulting in a spread of angles of the smectic layers with respect to at least one of the supporting plates, whereby a gradual transmission/voltage characteristic is achieved.
Claim 28
Dependent Claim
36 words
A method as claimed in claim 25, characterized in that the device is subjected to at least one low-frequency treatment at a high field strength after the low-frequency electric field treatment at a low field strength.
Claim 29
Dependent Claim
24 words
A method as claimed in claim 25, characterized in that the device is subjected to a plurality of low-frequency treatments at different field strengths.
Claim 30
Dependent Claim
20 words
A method as claimed in claim 25, characterized in that the electric field treatment is combined with a thermal treatment.
Claim 31
Dependent Claim
16 words
A method as claimed in claim 28, characterized in that the thermal treatment comprises local heating.
Claim 32
Dependent Claim
16 words
A method as claimed in claim 28, characterized in that the thermal treatment comprises local cooling.
Claim 33
Dependent Claim
18 words
A method as claimed in claim 28, characterized in that the thermal treatment comprises providing a thermal gradient.
Claim 34
Independent Claim
64 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, which device has transmission/voltage characteristic, characterized in that a spread of angles of the smectic layers with respect to at least one of the supporting plates is obtained by a thermal treatment, whereby a gradual transmission/voltage characteristic is achieved.
Claim 35
Independent Claim
64 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, which device has transmission/voltage characteristic, characterized in that a spread of angles of the smectic layers with respect to at least one of the supporting plates is obtained by a thermal treatment, whereby a gradual transmission/voltage characteristic is achieved.
Claim 36
Independent Claim
68 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission/voltage characteristic, characterized in that a spread of angles of the smectic layers with respect to at least one of the supporting plates is obtained by a mechanical or a chemical treatment, whereby a gradual transmission/voltage characteristic is achieved.
Claim 37
Independent Claim
68 words
A method of manufacturing a liquid crystal display device comprising a ferroelectric liquid crystal medium having smectic layers between two supporting plates provided with electrodes, said device has a transmission/voltage characteristic, characterized in that a spread of angles of the smectic layers with respect to at least one of the supporting plates is obtained by a mechanical or a chemical treatment, whereby a gradual transmission/voltage characteristic is achieved.
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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) | 1995-09-29 | 1996-03-30 | 1996-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-29 | 2000-03-30 | 2000-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-29 | 2004-03-30 | 2004-09-29 | $7700.00 | Window Closed / Lapsed |