US4411494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Roughening surfaces for homeotropic layers of smectic LCD's
Assignee: STC PLC
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Filing: 1980-11-21
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Granted: 1983-10-25
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Expires: 2000-11-21
Abstract
Abstract An internally electroded smectic liquid crystal display cell having a layer of a smectic material sandwiched between two electroded plates having electrodes that overlap at least in part wherein each said electrode is covered with an electrically insulating coherent layer whose surface has been treated to provide it with a rough texture provides a liquid crystal display cell of low voltage threshold characteristics.
Inventors
- 👤 William A. Crossland
- 👤 David Coates
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:27
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1337
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
121 words
A liquid crystal display comprising: a pair of spaced opposed glass plates each having an inward facing surface; a pair of opposed transparent electrodes each supported by a different one of said inward facing surfaces; liquid crystal material in homeotropic alignment sandwiched between said electrodes; and a layer of transparent electrically insulating coherent silica deposited on each of said electrodes, each of said layers having an etch roughened surface comprising a plurality of peaks in the range of about 50-190 peaks of 20 A or greater per mm length across an associated one of said electrodes to provide a rough surface for said associated one of said electrodes adjacent said material so that said display has a low switching voltage threshold.
Claim 2
Dependent Claim
121 words
A liquid crystal display comprising: a pair of spaced opposed glass plates each having an inward facing surface; a pair of opposed transparent electrodes each supported by a different one of said inward facing surfaces; liquid crystal material in homeotropic alignment sandwiched between said electrodes; and a layer of transparent electrically insulating coherent silica deposited on each of said electrodes, each of said layers having an etch roughened surface comprising a plurality of peaks in the range of about 50-190 peaks of 20 A or greater per mm length across an associated one of said electrodes to provide a rough surface for said associated one of said electrodes adjacent said material so that said display has a low switching voltage threshold.
Claim 3
Independent Claim
111 words
A method of forming a smectic cell having a low switching voltage threshold comprising the steps of: providing two spaced, parallel glass plates each having an inwardly facing surface; disposing a transparent electrode on each of said inwardly facing surfaces; depositing by a chemical vapor reaction a transparent layer of silica on each of said electrodes; etching each of said layers for a predetermined period of time to provide a roughened inwardly facing surface of a predetermined roughness for each of said electrodes so that said display has said low switching voltage threshold; assembling said plates to define a cell; filling said cell with a smectic material; and sealing said cell.
Claim 4
Independent Claim
111 words
A method of forming a smectic cell having a low switching voltage threshold comprising the steps of: providing two spaced, parallel glass plates each having an inwardly facing surface; disposing a transparent electrode on each of said inwardly facing surfaces; depositing by a chemical vapor reaction a transparent layer of silica on each of said electrodes; etching each of said layers for a predetermined period of time to provide a roughened inwardly facing surface of a predetermined roughness for each of said electrodes so that said display has said low switching voltage threshold; assembling said plates to define a cell; filling said cell with a smectic material; and sealing said cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |