US4765718A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Collimated light source for liquid crystal display utilizing internally reflecting light pipe collimator with offset angle correction
Assignee: General Electric Co
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Filing: 1987-11-03
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Granted: 1988-08-23
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Expires: 2007-11-03
Abstract
Abstract A collimated light source for Liquid Crystal Display includes a light integrating sphere and an internally reflective light pipe means for producing a relatively collimated light beam for illuminating a liquid crystal display. Compensation for offset or skew angle of the collimated light near the edge of the light pipe is provided by a secondary collimator taking the form of crossed cylindrical lenses.
Inventors
- 👤 John L. Henkes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:17
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133524
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
141 words
A high contrast liquid crystal display system including: (a) a liquid crystal display element, (b) a collimated light source positioned to illuminate one side of said display comprising: (1) a light integrating sphere containing a source of uncollimated light and having an opening to permit a portion of the uncollimated light to exit from the sphere; (2) elongated tapered light pipe means, one end of said light pipe means positioned adjacent the opening in said sphere and the other end being positioned adjacent to said display whereby light exiting from said sphere is internally reflected in said pipe means to illuminate said display with a collimated light beam, (c) secondary light collimating means between said light pipe means and said display to compensate for the offset angle from normal of the light emitted from the end of said light pipe means.
Claim 2
Dependent Claim
141 words
A high contrast liquid crystal display system including: (a) a liquid crystal display element, (b) a collimated light source positioned to illuminate one side of said display comprising: (1) a light integrating sphere containing a source of uncollimated light and having an opening to permit a portion of the uncollimated light to exit from the sphere; (2) elongated tapered light pipe means, one end of said light pipe means positioned adjacent the opening in said sphere and the other end being positioned adjacent to said display whereby light exiting from said sphere is internally reflected in said pipe means to illuminate said display with a collimated light beam, (c) secondary light collimating means between said light pipe means and said display to compensate for the offset angle from normal of the light emitted from the end of said light pipe means.
Claim 3
Dependent Claim
36 words
The liquid crystal display system according to claim 1 wherein said secondary collimating means comprises cylindrical lens means for bending light emitted from the end of said light pipe means to compensate for the offset angle.
Claim 4
Dependent Claim
34 words
The liquid crystal display according to claim 2 wherein the focal length of said cylindrical lens means causes the light to bend in a direction and by an amount equal to the offset angle.
Claim 5
Dependent Claim
37 words
The liquid crystal display according to claim 3 wherein said light pipe means is tapered in the horizontal and vertical planes and said secondary collimator comprises crossed cylindrical lenses to compensate for offset angle in both planes.
Claim 6
Dependent Claim
20 words
The liquid crystal display according to claim 3 wherein said light pipe means comprised a plurality of tapered light pipes.
Claim 7
Dependent Claim
36 words
The liquid crystal display according to claim 5 wherein said light pipes are tapered in the horizontal and vertical planes and said secondary collimator comprises crossed cylindrical lenses to compensate for offset angle in both planes.
References Cited (Backward Citations)
US4299447A
Cited
US4330813A
Cited
US4487481A
Cited
US4560999A
Cited
GB2157049A
Cited
US4704004A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |