Patent US3832031A successfully refreshed from Google Patents.
US3832031A
Expired / Lapsed
US
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Projection system
Assignee: Polaroid Corp
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Filing: 1969-12-24
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Granted: 1974-08-27
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Expires: 1989-12-24
Abstract
Abstract A projection system, particularly a rear, or back-lighted, projection system, wherein the screen is composed of a synthetic polymeric film, at least one surface of said film having been contacted with a solvent therefor for a time sufficient to impart translucency to said film.
Inventors
- 👤 E Land
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:34
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62; B; B29; B29D; B29D11/00; B29D11/0074
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
78 words
In a rear projection system which includes an image projector and a screen positioned in the focal plane of said image porjector, said projector adapted to project a color image onto said screen, the improvement which comprises employing as a screen an initially transparent biaxially oriented polystyrene sheet wherein at least one surface of said sheet has been contacted substantially evenly, subsequent to orientation with a solvent therefor for a time sufficient to provide translucency to said sheet.
Claim 2
Dependent Claim
78 words
In a rear projection system which includes an image projector and a screen positioned in the focal plane of said image porjector, said projector adapted to project a color image onto said screen, the improvement which comprises employing as a screen an initially transparent biaxially oriented polystyrene sheet wherein at least one surface of said sheet has been contacted substantially evenly, subsequent to orientation with a solvent therefor for a time sufficient to provide translucency to said sheet.
Claim 3
Dependent Claim
13 words
A product as defined in claim 1 wherein said solvent is a ketone.
Claim 4
Dependent Claim
18 words
A product as defined in claim 1 wherein said sheet is laminated to a transparent dimensionally stable support.
Claim 5
Dependent Claim
12 words
A product as defined in claim 3 wherein said support is glass.
Claim 6
Dependent Claim
13 words
A product as defined in claim 3 wherein said support is polymethyl methacrylate.
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) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |