US3669771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of etching a shadow mask
Assignee: Zenith Electronics LLC
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Filing: 1970-01-28
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Granted: 1972-06-13
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Expires: 1990-01-28
Abstract
Abstract A SHADOW MASK FOR A COLOR TELEVISION TUBE, HAVING A PATTERN OF APERTURES DIMENSIONED AS REQUIRED FOR SCREENING, IS FURTHER ETCHED AFTER THE SCREENING PROCESS TO ATTAIN A HOLE SIZE LARGER THAN THE PHOSPHOR DEPOSITS OF THE SCREEN. THE RE-ETCHING OCCURS IN SEVERAL STAGES AND A DENSITOMER ASSOCIATED WITH ONE SUCH STAGE MEASURES THE HOLE SIZE AND DERIVES A VOLTAGE USED TO CONTROL THE ETCHING TIME SO THAT THE APERTURES OF THE RE-ETCHED MASK ARE PRECISELY CONTROLLED TO A DESIRED SIZE.
Inventors
- 👤 Martin L Lerner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:33
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/14; H01J9/142
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |