US5089883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color television projection device with cathodoluminescent light sources
Assignee: US Philips Corp
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Filing: 1989-10-27
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Granted: 1992-02-18
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Expires: 2009-10-27
Abstract
Abstract The invention relates to a color television projection device having three planar monochromatic light sources for the background illumination of a viewing screen, in which a matrix-shaped electro-optical light valve is associated with each light source characterized in that the light sources are cathodo luminescent.
Inventors
- 👤 Thomas Welker
- 👤 Thomas Zaengel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:47
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/74; H04N9/00; H04N9/12; H04N9/31; H04N9/3141; H04N9/315
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
36 words
A colour television projection device having three planar monochromatic light sources, a matrix-shaped electro-optical light valve associated with each light source, and a viewing screen, characterized in that the light sources are cathodo luminescent light sources.
Claim 2
Dependent Claim
36 words
A colour television projection device having three planar monochromatic light sources, a matrix-shaped electro-optical light valve associated with each light source, and a viewing screen, characterized in that the light sources are cathodo luminescent light sources.
Claim 3
Dependent Claim
24 words
A colour television projection device as claimed in claim 1, characterized in that the light valves are thin film transistor-switched liquid crystal light valves.
Claim 4
Dependent Claim
44 words
A colour television projection device as claimed in claim 1, characterized in that the cathodo luminescent light sources each comprise a front substrate, a layer of cathodo luminescent material on the substrate, and a multilayer interference filter (6) between the substrate and the layer.
Claim 5
Dependent Claim
25 words
A colour television projection device as claimed in claim 3, characterized in that cooling means is provided between the front substrate and the light valve.
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) | 1995-02-17 | 1995-08-19 | 1996-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-17 | 1999-08-19 | 2000-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-17 | 2003-08-19 | 2004-02-18 | $7700.00 | Window Closed / Lapsed |