Patent US4708435A successfully refreshed from Google Patents.
US4708435A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rear projection screen
Assignee: Mitsubishi Chemical Corp
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Filing: 1986-10-30
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Granted: 1987-11-24
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Expires: 2006-10-30
Abstract
Abstract A rear projection screen is provided for observing an image by introducing light from the rear side of the screen at a sharp angle. The screen has a plane of incidence which comprises a plurality of prisms extending in lines or arcs. Each prism has a total reflection surface which totally reflects incident light so that the light emerges toward an observer and a surface opposite to the total reflection surface, and toward the total reflection surface and/or the opposite surface having a curved surface so that the luminous flux of the totally reflected light is once converged and is then diffused.
Inventors
- 👤 Yukio Yata
- 👤 Shingo Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:12
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62; G03B21/625
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
92 words
A rear projection screen in which a light is introduced from a rear surface at a sharp angle for viewing an image, comprising a plurality of prisms extending along lines or circular arcs provided on said rear surface, and each prism constituting said prisms has a total reflection surface which totally reflects the incident light and emerges to a viewing side, said total reflection surface and/or the surface opposite to said total reflection surface having curved surface so that the luminous flux of the totally reflected light, is converged and then diffused.
Claim 2
Dependent Claim
92 words
A rear projection screen in which a light is introduced from a rear surface at a sharp angle for viewing an image, comprising a plurality of prisms extending along lines or circular arcs provided on said rear surface, and each prism constituting said prisms has a total reflection surface which totally reflects the incident light and emerges to a viewing side, said total reflection surface and/or the surface opposite to said total reflection surface having curved surface so that the luminous flux of the totally reflected light, is converged and then diffused.
Claim 3
Dependent Claim
18 words
A rear projection screen according to claim 1 comprising lenticular lens surfaces vertically extending on the viewing side.
Claim 4
Dependent Claim
17 words
A rear projection screen according to claim 2 comprising lenticular lens surfaces provided with total reflection surfaces.
Claim 5
Dependent Claim
29 words
A rear projection screen according to claim 2 or 3, characterized in that an external light absorbing layer is formed on the light nontransmissive portion of said lenticular lens.
Claim 6
Dependent Claim
28 words
A rear projection screen according to claim 3, characterized in that an external light absorbing layer is formed on said total reflection surfaces through a light reflecting layer.
Claim 7
Dependent Claim
24 words
A rear projection screen according to any one of claims 1 to 5 characterized by having a circular Fresnel lens on said viewing side.
Claim 8
Dependent Claim
28 words
A rear projection screen according to any one of claims 1 to 6, characterized in that a substrate constituting said screen is provided with a light diffusing means.
Claim 9
Dependent Claim
26 words
A rear projection screen according to any one of claims 1 to 3 characterized by being combined with a separate sheet having a lenticular lens surface.
Claim 10
Dependent Claim
31 words
A rear projection screen according to claim 8, characterized in that an external light absorbing layer is formed on the light nontransmissive portion of the lenticular lens of said separate sheet.
Claim 11
Dependent Claim
23 words
A rear projection screen according to claim 8 or 9, characterized in that said separate sheet is provided with a light diffusing means.
Claim 12
Dependent Claim
20 words
A rear projection screen according to claim 1, wherein the total reflection surface of each prism has a curved surface.
Claim 13
Dependent Claim
27 words
A rear projection screen according to claim 1, wherein the surface of each prism opposite to said total reflection surface of each prism has a curved surface.
Claim 14
Dependent Claim
31 words
A rear projection screen according to claim 1, wherein the total reflection surface of each prism and the surface opposite of each prism to said total reflection surface have curved surfaces.
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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) | 1990-11-23 | 1991-05-25 | 1991-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-23 | 1995-05-25 | 1995-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-23 | 1999-05-25 | 1999-11-24 | $7700.00 | Window Closed / Lapsed |