Patent US4975619A successfully refreshed from Google Patents.
US4975619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface treatment of silica-coated phosphor particles and method for a CRT screen
Assignee: RCA Licensing Corp
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Filing: 1989-12-22
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Granted: 1990-12-04
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Expires: 2009-12-22
Abstract
Abstract A method of surface-treating dry-powdered phosphor particles to control the triboelectric charge characteristics thereof includes the steps of providing the phosphor particles with a first coating of silica, dissolving a coupling agent selected from the group consisting of silanes and titanates in a suitable solvent to form a mixture, surface-coating the silica-coated phosphor particles with the mixture to provide a second coating of the coupling agent on the phosphor particles, filtering the surface-treated particles, rinsing the surface-treated particles with the solvent, and drying the surface-treated particles. The resultant dry-powdered surface-treated phosphor particles are used to make a luminescent viewing screen for a CRT. The coupling agent overlying the silica coating controls the triboelectric charging characteristics of the phosphor particles during the electrophotographic manufacturing of the screen.
Inventors
- 👤 Pabitra Datta
- 👤 Ronald N. Friel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:58
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/02; C09K11/025
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
86 words
A CRT comprising an electrophotographically manufactured luminescent viewing screen and means for selectively exciting areas of said screen to luminescence, said screen comprising a layer of dry-powdered phosphor particles emissive to light in a particular portion of the visible spectrum, said dry-powdered phosphor particles having a first coating of silica thereon and a second coating of a coupling agent selected from the group consisting of silanes and titanates overlying said first coating, to control the surface charge of said particles during the manufacturing of said screen.
Claim 2
Dependent Claim
86 words
A CRT comprising an electrophotographically manufactured luminescent viewing screen and means for selectively exciting areas of said screen to luminescence, said screen comprising a layer of dry-powdered phosphor particles emissive to light in a particular portion of the visible spectrum, said dry-powdered phosphor particles having a first coating of silica thereon and a second coating of a coupling agent selected from the group consisting of silanes and titanates overlying said first coating, to control the surface charge of said particles during the manufacturing of said screen.
Claim 3
Dependent Claim
110 words
A CRT comprising an electrophotographically manufactured luminescent viewing screen and means for selectively exciting areas of said screen to luminescence, said screen comprising a layer of dry-powdered phosphor particles emissive to light in a particular portion of the visible spectrum, said dry-powdered phosphor particles having a first coating of silica thereon and a second coating of a coupling agent overlying said first coating, to control the surface charge of said particles during the manufacturing of said screen, said coupling agent being selected from the group consisting of N(2-aminoethyl-3-aminopropyl) methyl dimethoxysilane, (aminopropyl) triethoxysilane, 3-(aminopropyl) dimethylethoxysilane, N-(aminoethyl-3-aminopropyl) triethoxysilane, (methacryloxy proply)trimethoxysilane, isopropyl-tri (dioctyl-pyrophosphato) titanate, (n-decyl) methyl dichlorosilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-dimethyl chlorosilane, and (tridecafluoro 1,1,2,2-tetrahydro octyl)-1-dimethyl-triethoxysilane.
Claim 4
Dependent Claim
110 words
A CRT comprising an electrophotographically manufactured luminescent viewing screen and means for selectively exciting areas of said screen to luminescence, said screen comprising a layer of dry-powdered phosphor particles emissive to light in a particular portion of the visible spectrum, said dry-powdered phosphor particles having a first coating of silica thereon and a second coating of a coupling agent overlying said first coating, to control the surface charge of said particles during the manufacturing of said screen, said coupling agent being selected from the group consisting of N(2-aminoethyl-3-aminopropyl) methyl dimethoxysilane, (aminopropyl) triethoxysilane, 3-(aminopropyl) dimethylethoxysilane, N-(aminoethyl-3-aminopropyl) triethoxysilane, (methacryloxy proply)trimethoxysilane, isopropyl-tri (dioctyl-pyrophosphato) titanate, (n-decyl) methyl dichlorosilane, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)-1-dimethyl chlorosilane, and (tridecafluoro 1,1,2,2-tetrahydro octyl)-1-dimethyl-triethoxysilane.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-03 | 1994-06-04 | 1994-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-03 | 1998-06-04 | 1998-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-03 | 2002-06-04 | 2002-12-04 | $7700.00 | Window Closed / Lapsed |