US4969732A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display device
Assignee: Central Research Laboratories Ltd
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Filing: 1989-02-23
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Granted: 1990-11-13
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Expires: 2009-02-23
Abstract
Abstract A display device includes equipment for projecting light onto a surface. The equipment includes a beam-splitter for effecting partial reflection and partial transmittance of an incident beam. On one side of the beam-splitter are a light source for directing light onto the beam-splitter and a mirror for directing back towards the beam-splitter light reflected therefrom. On the other side of the beam-splitter is a louvre for permitting passage therethrough of light of incident angle relative to a normal to the beam-splitter with in a predetermined restricted range.
Inventors
- 👤 Graham L. Wright
- 👤 Mark Dempster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:53
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/74; H04N5/7408; G; G02; G02B; G02B17/00; G02B17/02; G03; G03B; G03B21/00; G03B21/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
98 words
Equipment for projecting light onto a surface, the equipment comprising: beam-splitting means for effecting partial reflection and partial transmittance of an incident beam; a light source located on one side of the beam-splitting means for directing light onto the beam-splitting means; mirror means on said one side of the beam-splitting means for directing back towards the beam-splitting means light reflected from the beam-splitting means; and louvre means located on the other side of the beam-splitting means for permitting passage therethrough of light in a predetermined restricted range of incident angles relative to a normal to the beam-splitting means.
Claim 2
Dependent Claim
98 words
Equipment for projecting light onto a surface, the equipment comprising: beam-splitting means for effecting partial reflection and partial transmittance of an incident beam; a light source located on one side of the beam-splitting means for directing light onto the beam-splitting means; mirror means on said one side of the beam-splitting means for directing back towards the beam-splitting means light reflected from the beam-splitting means; and louvre means located on the other side of the beam-splitting means for permitting passage therethrough of light in a predetermined restricted range of incident angles relative to a normal to the beam-splitting means.
Claim 3
Dependent Claim
20 words
Equipment according to claim 1 wherein the light source includes a display panel for producing an image to be projected.
Claim 4
Dependent Claim
28 words
Equipment according to claim 1 wherein said predetermined restricted range of incident angles relative to a normal to the beam-splitting means varies with position along the louvre means.
Claim 5
Dependent Claim
59 words
Equipment according to claim 3, the louvre means comprising a substrate having a plurality of passageways arranged in side-by-side relation for allowing transmission of light of an incident angle relative to an axis of a passageway within a predetermined range wherein two or more adjacent passageways have a transmission direction at an angle of deviation from a parallel relationship.
Claim 6
Dependent Claim
19 words
Equipment according to claim 1 further comprising a Fresnel lens arrangement intermediate the beam-splitting means and the louvre means.
Claim 7
Dependent Claim
18 words
Equipment according to claim 1 wherein the beam-splitting means comprises a substrate having alternating reflective and transparent strips.
Claim 8
Dependent Claim
27 words
Equipment according to claim 1 wherein an anti-reflection coating is provided on a surface of the beam-splitting means on said other side of the beam splitting means.
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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) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |