US3814966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Post-deflection acceleration type color cathode-ray tube
Assignee: Hitachi Ltd
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Filing: 1972-09-07
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Granted: 1974-06-04
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Expires: 1992-09-07
Abstract
Abstract A post-deflection acceleration type color cathode-ray tube including a shadow mask having on the surface thereof a secondary electron emission preventing layer made of graphite. Such graphite layers may also be applied on the phosphor screen and on the inner surface of the funnel portion of the tube to further improve the secondary electron preventing effect.
Inventors
- 👤 A Misumi
- 👤 T Kasai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:19
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/80; H01J29/81; H01J29/02; H01J29/10; H01J29/18; H01J29/28
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
81 words
In a post-deflection acceleration type color cathode-ray tube comprising electron gun means, a shadow mask having through holes therein and a metal-backed phosphor screen, the improvement comprising a secondary electron preventing layer made of graphite, said layer being provided at least on that surface of said shadow mask which faces said electron gun means, the thickness and the density of said secondary electron preventing layer being in the ranges of about 3 - 20 Mu and about 0.3 2.25 g/cm3, respectively.
Claim 2
Dependent Claim
81 words
In a post-deflection acceleration type color cathode-ray tube comprising electron gun means, a shadow mask having through holes therein and a metal-backed phosphor screen, the improvement comprising a secondary electron preventing layer made of graphite, said layer being provided at least on that surface of said shadow mask which faces said electron gun means, the thickness and the density of said secondary electron preventing layer being in the ranges of about 3 - 20 Mu and about 0.3 2.25 g/cm3, respectively.
Claim 3
Dependent Claim
51 words
The color cathode-ray tube according to claim 1, wherein secondary electron preventing graphite layers are provided on both surfaces of said shadow mask and the walls of said through holes in said shadow mask, on said metal-backed phosphor screen and on the inner surface of the funnel portion of the tube.
Claim 4
Dependent Claim
27 words
The color cathode-ray tube according to claim 1, wherein the graphite particles constituting said secondary electron preventing layer having a particle diameter of about 1 Mu .
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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |