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US5495306A Expired / Lapsed US ⏱️ 0.0 years remaining

Projector

Assignee: Sharp Corp
•
Filing: 1995-04-17
•
Granted: 1996-02-27
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Expires: 2015-04-17
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Abstract

Abstract A projector has a shortened optical path from a light valve to a screen and a reduction in the depth size of its system and requires less space to mount. Rays of light emitted from a light valve of the projects are refracted by a converging lens and reflected by a plane mirror to converge at the primary focal point of an elliptical mirror, and then travel toward the secondary focal point whereat the focal point of a parabolic mirror also exists and a projection lens is disposed. The light rays pass through the projection lens, are reflected by the parabolic mirror and then are brought to a parallel beam of light that is further collected by a Fresnel lens to finally form an image on a lenticular lens-screen.

Inventors

  • 👤 Shigeru Shibazaki

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 15:42
CPC Classifications
G; G02; G02B; G02B17/00; G02B17/08; G02B17/0804; G02B17/0816; G03; G03B; G03B21/00; G03B21/10; G09; G09F; G09F9/00; G09F9/30; G09F9/35; H; H04; H04N; H04N5/00; H04N5/74; H04N5/7416; H04N5/7441

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 101 words
A projector, comprising: a light valve emitting a parallel beam of light; a parabolic mirror causing the rays of the parallel beam of light to converge at its focal point; a projection lens disposed at the focal point of the parabolic mirror; and an elliptical mirror having a primary focal point coexisting with the focal point of the parabolic mirror and reflecting the rays of the beam of light from the projection lens to converge the rays at its secondary focal point, whereby the rays of the beam of light reflected by the elliptical mirror are collected to form an image.
Claim 2
Dependent Claim 101 words
A projector, comprising: a light valve emitting a parallel beam of light; a parabolic mirror causing the rays of the parallel beam of light to converge at its focal point; a projection lens disposed at the focal point of the parabolic mirror; and an elliptical mirror having a primary focal point coexisting with the focal point of the parabolic mirror and reflecting the rays of the beam of light from the projection lens to converge the rays at its secondary focal point, whereby the rays of the beam of light reflected by the elliptical mirror are collected to form an image.
Claim 3
Dependent Claim 24 words
The projector of claim 1, further comprising a light source and a beam splitter, wherein the light valve is a reflection type liquid-crystal display.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1999-02-26 1999-08-28 2000-02-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2003-02-26 2003-08-28 2004-02-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2007-02-26 2007-08-28 2008-02-27 $7700.00 Window Closed / Lapsed

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