US3682530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymeric rear projection screens
Assignee: Eastman Kodak Co
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Filing: 1970-09-24
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Granted: 1972-08-08
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Expires: 1990-09-24
Abstract
Abstract A rear projection screen comprising a sheet of polymeric material consisting essentially of polypropylene. The sheet comprises two surface layers and a core layer containing crystalline spherulites. The core layer contains larger spherulites than the two surface layers.
Inventors
- 👤 James J De Palma
- 👤 Edward D Morrison
- 👤 Robert F Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:53
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
30 words
A rear projection screen as in claim 1, wherein said sheet has one randomly roughened surface; the roughness of said roughened surface being from about 10 to about 25 microinches.
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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |