US3772103A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etch-back screening
Assignee: Zenith Electronics LLC
•
Filing: 1971-04-01
•
Granted: 1973-11-13
•
Expires: 1991-04-01
Abstract
Abstract A shadow mask is initially prepared with apertures dimensioned for photoresist screening of a color picture tube and, after screening has been accomplished, the mask is re-etched to enlarge the apertures to a desired size in relation to the phosphor deposits. An improvement in the re-etch process is achieved by utilizing a substantially saturated solution of the etchant in the re-etch step.
Inventors
- 👤 J Holowka
- 👤 M Lerner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:54
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/14; H01J9/142
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
48 words
The method of manufacturing a color tube in accordance with claim 1 in which said mask is given a surface oxidation prior to its use in said photomechanical printing process, and in which said mask is stripped of its surface oxidation prior to the enlarging of its apertures.
Claim 2
Dependent Claim
86 words
The method of manufacturing a color tube in accordance with claim 2 in which said apertures of said mask are circular and individually comprise a small diameter opening on one surface of said mask, a concentric large diameter opening on the opposite surface of said mask with an interconnecting recess configured to provide a feathered, reduced thickness wall section around said small diameter opening, and in which said apertures are enlarged by spraying said saturated solution on said mask to etch away said feathered wall section.
Claim 3
Dependent Claim
31 words
The method of manufacturing a color tube in accordance with claim 3 in which said mask has a dome-shaped or spherical configuration and is positioned essentially horizontally during said enlarging step.
Claim 4
Dependent Claim
34 words
The method of manufacturing a color tube in accordance with claim 4 in which said etchant solution further includes free hydrochloric acid in the amount of about 1 to 2 per cent by weight.
References Cited (Backward Citations)
US2961314A
Cited
US3502519A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |