US5142373A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rear projection television set having improved contrast
Assignee: Pioneer Corp
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Filing: 1990-12-05
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Granted: 1992-08-25
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Expires: 2010-12-05
Abstract
Abstract A rear projection television set is of the construction in which an image light projected from a projection cathode ray tube is reflected by a mirror onto the rear surface of a screen comprising a Fresnel lens and the light passes through the front surface of the screen to be viewed by viewers. The condensing distance of the Fresnel lens is selected to be less than four meters for radii of up to 300(S/40) millimeters of the Fresnel lens when the mirror is positioned relative to the screen such that A≦200+(S-40)×10 millimeters, where S is the diagonal distance of the screen in inches and A is the shortest distance between the mirror and the screen.
Inventors
- 👤 Kazuya Akiyama
- 👤 Masaru Nozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:44
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/14; G03B21/28; G03B21/54; G03B21/56; G03B21/60; G03B21/62; H; H04; H04N; H04N5/00; H04N5/74; H04N5/7408
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
159 words
A rear projection television comprising: a projector for projecting a light image; a mirror for reflecting the light image from said projector; and a screen including a Fresnel lens on a rear surface thereof positioned opposite to said mirror for receiving the light reflected from said mirror, said Fresnel lens having a condensing distance and a center located at a center of said screen, said screen passing the light image from said mirror through a front surface thereof so that the light through the front surface of said screen is viewed at a distance away from the front surface of the lens is selected to be less than four meters for radii of up to 300(S/40) millimeters of said Fresnel lens when said mirror is positioned relative to said screen such that A≦200+(S-40)×10 where S is the diagonal distance of said screen in inches and A is the shortest distance between said mirror and said screen expressed in millimeters.
Claim 2
Dependent Claim
159 words
A rear projection television comprising: a projector for projecting a light image; a mirror for reflecting the light image from said projector; and a screen including a Fresnel lens on a rear surface thereof positioned opposite to said mirror for receiving the light reflected from said mirror, said Fresnel lens having a condensing distance and a center located at a center of said screen, said screen passing the light image from said mirror through a front surface thereof so that the light through the front surface of said screen is viewed at a distance away from the front surface of the lens is selected to be less than four meters for radii of up to 300(S/40) millimeters of said Fresnel lens when said mirror is positioned relative to said screen such that A≦200+(S-40)×10 where S is the diagonal distance of said screen in inches and A is the shortest distance between said mirror and said screen expressed in millimeters.
Claim 3
Dependent Claim
20 words
A rear projection television according to claim 1, wherein said screen includes a lenticular sheet having cylindrical lenses extending vertically.
Claim 4
Dependent Claim
15 words
A rear projection television according to claim 1 wherein said projector includes cathode ray tubes.
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) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |