Patent US4185220A successfully refreshed from Google Patents.
US4185220A
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Cathode ray display tube with contrast enhancement panel
Assignee: Westinghouse Electric Corp
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Filing: 1977-06-30
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Granted: 1980-01-22
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Expires: 1997-06-30
Abstract
Abstract A cathode ray display tube is provided with a contrast enhancement panel which is optically coupled to the tube faceplate. The contrast enhancement panel has a viewing surface which is spherical and concave with respect to a viewer.
Inventors
- 👤 Albert E. Oberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:20
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J29/896
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
123 words
A cathode ray display tube having a display faceplate with a luminescent material disposed on the interior tube side of a light transmissive faceplate, the improvement wherein a limited light transmissive contrast enhancement panel is optically coupled to and mounted directly on a light transmissive clear resin layer disposed on the exterior surface of the faceplate, which resin layer closely matches the index of refraction of the faceplate, and which contrast enhancement panel has a viewing surface which is spherical and concave with respect to a viewer, with the radius of curvature of the spherical viewing surface approximately equal to a predetermined viewer distance, and wherein the overall light transmissivity of the faceplate, resin layer and contrast enhancement panel is about 10-15 percent.
Claim 2
Dependent Claim
123 words
A cathode ray display tube having a display faceplate with a luminescent material disposed on the interior tube side of a light transmissive faceplate, the improvement wherein a limited light transmissive contrast enhancement panel is optically coupled to and mounted directly on a light transmissive clear resin layer disposed on the exterior surface of the faceplate, which resin layer closely matches the index of refraction of the faceplate, and which contrast enhancement panel has a viewing surface which is spherical and concave with respect to a viewer, with the radius of curvature of the spherical viewing surface approximately equal to a predetermined viewer distance, and wherein the overall light transmissivity of the faceplate, resin layer and contrast enhancement panel is about 10-15 percent.
Claim 3
Dependent Claim
38 words
The display tube set forth in claim 1, wherein the contrast enhancement panel has a relatively low light transmissivity, and a circular polarizer is provided between the cathode ray tube faceplate exterior surface and the contrast enhancement panel.
References Cited (Backward Citations)
US2172775A
Cited
GB481445A
Cited
US2312206A
Cited
US2531956A
Cited
US2958801A
Cited
US3048729A
Cited
US3504212A
Cited
US3697154A
Cited
US3760215A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |