Patent US4177399A successfully refreshed from Google Patents.
US4177399A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High contrast cathode ray display tube
Assignee: Westinghouse Electric Corp
•
Filing: 1978-05-25
•
Granted: 1979-12-04
•
Expires: 1998-05-25
Abstract
Abstract A high contrast cathode ray display tube is provided by using a color filter glass faceplate for the tube which has a narrow band of transmissivity which closely matches the display phosphor emission.
Inventors
- 👤 Vincent J. Muccigrosso
- 👤 John L. Nivison
- 👤 Albert E. Oberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:47
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/18; H01J29/24; H01J29/86; H01J29/89; H01J29/896
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
132 words
A cathode ray display tube with improved contrast for viewing the display in high ambient light levels wherein the tube includes a display faceplate portion with a display screen phosphor layer on the interior surface of the faceplate portion, the improvement wherein the tube faceplate portion is formed of a glass which is a green color filter glass of low relative transmissivity of at least 0.1 over the range of 532 to 558 μm, and the transmissivity of the color filter glass peaks at about 0.125 at about 545 μm, and the phosphor layer is terbium activated gadolinium oxysulfide which exhibits cathodoluminescent emission such that a high percentage of the total phosphor emission energy is concentrated between 540-550 μm and within the narrow range of wavelength for which the glass transmissivity peaks.
Claim 2
Dependent Claim
132 words
A cathode ray display tube with improved contrast for viewing the display in high ambient light levels wherein the tube includes a display faceplate portion with a display screen phosphor layer on the interior surface of the faceplate portion, the improvement wherein the tube faceplate portion is formed of a glass which is a green color filter glass of low relative transmissivity of at least 0.1 over the range of 532 to 558 μm, and the transmissivity of the color filter glass peaks at about 0.125 at about 545 μm, and the phosphor layer is terbium activated gadolinium oxysulfide which exhibits cathodoluminescent emission such that a high percentage of the total phosphor emission energy is concentrated between 540-550 μm and within the narrow range of wavelength for which the glass transmissivity peaks.
References Cited (Backward Citations)
US2734142A
Cited
US2690554A
Cited
US2618759A
Cited
US3143683A
Cited
US3382393A
Cited
US3950668A
Cited
US3873868A
Cited
US3879627A
Cited
US3946267A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |