Patent US3940508A successfully refreshed from Google Patents.
US3940508A
Expired / Lapsed
US
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Precoating color television picture tube faceplate panels to promote phosphor pattern adherence
Assignee: Westinghouse Electric Corp
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Filing: 1974-09-16
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Granted: 1976-02-24
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Expires: 1994-09-16
Abstract
Abstract An improved precoat layer of highly insoluble, low molecular weight polyvinyl alcohol is uniformly thinly dispersed and dried upon the interior surface of a television picture tube faceplate panel. The precoat is applied by a slurry process with the aqueous slurry containing a predetermined amount of the normally soluble, low molecular weight polyvinyl alcohol and with the material being rendered highly insoluble by adjusting the pH value of the aqueous slurry to a value of less than about 3. The uniformly dispersed and dried precoat provides a highly adherent layer on the glass faceplate panel and the subsequently deposited phosphor pattern is highly adherent to this layer.
Inventors
- 👤 Harold D. Wilcox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:51
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/20; H01J9/22; H01J9/221; H01J9/223
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
93 words
Method of applying an insoluble adherent precoat layer on the faceplate of a color television picture tube over which the phosphor pattern is deposited, which method comprises: preparing an aqueous slurry containing from about 0.01 to 0.1 weight percent of normally soluble, low molecular weight polyvinyl alcohol having a molecular weight of less than about 50,000; adjusting the pH of the aqueous slurry to a value of less than about 3; uniformly dispersing a predetermined amount of the adjusted slurry over the faceplate and drying it thereon to form the insoluble precoat layer.
Claim 2
Dependent Claim
93 words
Method of applying an insoluble adherent precoat layer on the faceplate of a color television picture tube over which the phosphor pattern is deposited, which method comprises: preparing an aqueous slurry containing from about 0.01 to 0.1 weight percent of normally soluble, low molecular weight polyvinyl alcohol having a molecular weight of less than about 50,000; adjusting the pH of the aqueous slurry to a value of less than about 3; uniformly dispersing a predetermined amount of the adjusted slurry over the faceplate and drying it thereon to form the insoluble precoat layer.
Claim 3
Dependent Claim
24 words
The method specified in claim 1, wherein the aqueous slurry preferably contains about 0.05 weight percent of normally soluble, low molecular weight polyvinyl alcohol.
Claim 4
Dependent Claim
27 words
The method specified in claim 1, wherein the pH of the aqueous slurry is preferably adjusted by addition of an acid selected from hydrochloric and sulfuric acid.
Claim 5
Dependent Claim
14 words
The method specified in claim 1, wherein the adjusted pH is preferably about 2.5.
Claim 6
Dependent Claim
51 words
The method specified in claim 1, wherein the aqueous slurry is dispersed upon the faceplate by rotating the faceplate, and the drying is effected by heating the thinly coated faceplate by rotating the faceplate, and the drying is effected by heating the thinly coated faceplate to complete insolubilization of the precoat.
References Cited (Backward Citations)
US3269838A
Cited
US3712815A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |