Patent US3857628A successfully refreshed from Google Patents.
US3857628A
Expired / Lapsed
US
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Selective polarizer arrangement for liquid crystal displays
Assignee: F Hoffmann La Roche AG
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Filing: 1973-08-29
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Granted: 1974-12-31
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Expires: 1993-08-29
Abstract
Abstract A liquid crystal alpha-numeric display of the field effect type comprising a layer of nematic liquid crystal material sandwiched between transparent parallel plates, together with polarizers on opposite sides of the liquid crystal layer, and a reflector assembly behind the display. The invention is characterized in that the front polarizer on the side of the liquid crystal layer opposite the reflector assembly covers only the digit area of the display, leaving a border around the digit area which is not covered by the polarizer. This allows unpolarized light to pass through the display around the digits, giving greater contrast between the digits and the background area.
Inventors
- 👤 R Strong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:51
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1345; G02F1/1335; G02F1/133528
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A liquid crystal display comprising a layer of nematic liquid crystal material disposed between first and second transparent parallel plates, means for effecting a twisted nematic structure in said layer of liquid crystal material, said plates being coated on selected areas thereof with films of transparent conductive material with the conductive material on one plate comprising segments adapted to form symbols in an alpha-numeric display when an electrical field is established between selected segments on one plate and a film of conductive material on the other plate, polarizers on opposite sides of said layer of liquid crystal material with the polarizer adjacent said one plate covering said conductive segments while not covering at least a portion of said one plate around said segments, and a reflector for scattering polarized light behind said other plate.
Claim 2
Dependent Claim
134 words
A liquid crystal display comprising a layer of nematic liquid crystal material disposed between first and second transparent parallel plates, means for effecting a twisted nematic structure in said layer of liquid crystal material, said plates being coated on selected areas thereof with films of transparent conductive material with the conductive material on one plate comprising segments adapted to form symbols in an alpha-numeric display when an electrical field is established between selected segments on one plate and a film of conductive material on the other plate, polarizers on opposite sides of said layer of liquid crystal material with the polarizer adjacent said one plate covering said conductive segments while not covering at least a portion of said one plate around said segments, and a reflector for scattering polarized light behind said other plate.
Claim 3
Dependent Claim
35 words
The liquid crystal display of claim 1 wherein said polarizer adjacent said one plate covers only symbols formed by said conductive segments leaving a border around said symbols which is not covered by a polarizer.
Claim 4
Dependent Claim
12 words
The liquid crystal display of claim 1 wherein said polarizers are crossed.
Claim 5
Dependent Claim
15 words
The liquid crystal display of claim 1 wherein said polarizers are parallel to each other.
Claim 6
Dependent Claim
25 words
The liquid crystal display of claim 1 wherein said polarizers are on the sides of said transparent plates opposite said layer of liquid crystal material.
References Cited (Backward Citations)
US3731986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |