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US4440473A
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US
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Voltage polarity switching means for cholesteric liquid crystal displays
Assignee: REU BOIU RUDOLPH
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Filing: 1981-06-05
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Granted: 1984-04-03
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Expires: 2001-06-05
Abstract
Abstract A display device particularly adapted for use with a microfilm reader, in which an illuminating light source need be activated only in an initial reading stage. A first transparent electrode, a liquid crystal layer, a semiconductor layer and a second transparent electrode are stacked together in the stated order. A voltage is applied between the first and second transparent electrodes which is switched in a polarity between an initial reading mode and a display mode.
Inventors
- 👤 Souichi Sekimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:13
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/055; G02F1/0558; G02F1/13; G02F1/133; G02F1/135; G03; G03B; G03B21/00; G03B21/10; G03B21/11
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
102 words
A display device comprising: a first transparent electrode; a film layer having an electro-optical effect comprising a layer of nematic liquid crystal material containing several to several tens of percent of cholesteric liquid crystal material; a photosensitive film layer and a second transparent electrode, said first transparent electrode, said film layer having an electro-optical effect said photosensitive film layer and said second transparent electrode being stacked together in the stated order; means for providing a d.c. voltage across said first and second transparent electrodes; and means for switching the polarity of said d.c. voltage applied across said first and second transparent electrodes.
Claim 2
Dependent Claim
102 words
A display device comprising: a first transparent electrode; a film layer having an electro-optical effect comprising a layer of nematic liquid crystal material containing several to several tens of percent of cholesteric liquid crystal material; a photosensitive film layer and a second transparent electrode, said first transparent electrode, said film layer having an electro-optical effect said photosensitive film layer and said second transparent electrode being stacked together in the stated order; means for providing a d.c. voltage across said first and second transparent electrodes; and means for switching the polarity of said d.c. voltage applied across said first and second transparent electrodes.
Claim 3
Dependent Claim
153 words
A display device comprising: a first transparent electrode; a film layer having an electro-optical effect comprising a layer of nematic liquid crystal material containing several to several tens of percent of cholesteric liquid crystal material; a photosensitive film layer and a second transparent electrode, said first transparent electrode, said film layer having an electro-optical effect said photosensitive film layer and said second transparent electrode being stacked together in the stated order; means for providing a d.c. voltage across said first and second transparent electrodes; means for switching the polarity of said d.c. voltage applied across said first and second transparent electrodes; a light source; a microfilm; a reflector for directing light from said light source toward said microfilm; a condenser lens disposed between said light source and said microfilm; a projecting lens receiving light passing through microfilm; and a mirror for refracting light passing through said projecting lens onto said photosensitive film layer.
Claim 4
Dependent Claim
153 words
A display device comprising: a first transparent electrode; a film layer having an electro-optical effect comprising a layer of nematic liquid crystal material containing several to several tens of percent of cholesteric liquid crystal material; a photosensitive film layer and a second transparent electrode, said first transparent electrode, said film layer having an electro-optical effect said photosensitive film layer and said second transparent electrode being stacked together in the stated order; means for providing a d.c. voltage across said first and second transparent electrodes; means for switching the polarity of said d.c. voltage applied across said first and second transparent electrodes; a light source; a microfilm; a reflector for directing light from said light source toward said microfilm; a condenser lens disposed between said light source and said microfilm; a projecting lens receiving light passing through microfilm; and a mirror for refracting light passing through said projecting lens onto said photosensitive film layer.
Claim 5
Dependent Claim
19 words
The display device of claim 1 or 2 wherein said photosensitive film layer comprises an erasable photo-sensitive film layer.
Claim 6
Dependent Claim
16 words
The display device of claim 1 or 2 wherein said photosensitive material comprises a semiconductor material.
Claim 7
Dependent Claim
29 words
The display device of claim 4 wherein said semiconductor material comprises a material selected from the group consisting of Se, Se-Te-As, SbS, AsS, Se-As, Se-Sb, ZnSe, CdSe and CdS.
Claim 8
Dependent Claim
31 words
The display device of any of claims 1, 3, 4 or 5 further comprising a spacer layer disposed between said film layer having an electro-optical effect and said photosensitive film layer.
Claim 9
Dependent Claim
39 words
The display device of any of claims 1, 3, 4 or 5 further comprising first and second substrates sandwiching said first transparent electrode, said film layer having an electro-optical effect, said photosensitive film layer and said second transparent electrode.
Claim 10
Dependent Claim
33 words
The display device of any of claims 1, 3, 4 or 5 wherein said photosensitive film layer has a black coating on the side thereof adjacent said film layer having an electro-optical effect.
Claim 11
Dependent Claim
20 words
The display device of any of claims 1, 3, 4 or 5 further comprising utilizing means in a microfilm reader.
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) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |