US3751135A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rear projection screen
Assignee: Individual
•
Filing: 1972-06-23
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Granted: 1973-08-07
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Expires: 1992-06-23
Abstract
Abstract A screen for rear projection the image forming element which consists of a sheet having a thickness of 0.2 - 1.5 mm and consisting of opaline polymethyl methacrylate containing dispersed calcium and/or magnesium carbonate of a grain size less than 1 Mu , said sheet either having a covering at the rear side consisting of a transparent lacquer having a thickness of 10 100 Mu wherein glass particles having a grain size of 5 - 50 Mu are dispersed or glass particles of said kind being dispersed in the material of which the sheet consists.
Inventors
- 👤 E Clausen
- 👤 J Clausen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 03:31
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
90 words
Rear projection screen comprising a sheet of polymethyl methacrylate having a thickness between 0.2 mm and 1.5 mm and containing approximately 1 percent silicone oil having a viscosity of approximately 100 c.p. and approximately 1 o/oo benzoyl-peroxide wherein 0.5 - 1.5 percent calcium and/or magnesium carbonate having an average grain size less than 1 Mu is dispersed, said sheet having a coating consisting of a transparent lacquer having a thickness of 10 - 100 Mu and containing glass particles having an average grain size between 5 and 50 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) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |