US4373282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin-panel illuminator for front-lit displays
Assignee: Raytheon Co
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Filing: 1981-05-29
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Granted: 1983-02-15
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Expires: 2001-05-29
Abstract
Abstract A device for illuminating a display surface. Light is introduced through an end surface of a transparent substrate having front and back plane parallel opposed surfaces and thereby directed into the interior of the substrate. The back surface is textured with a multiplicity of shallow depressions such as grooves or dimples which have shallow sloped sides. These sides are configured so that light is selectively directed from the interior of the substrate through a limited angle out of the substrate towards a display surface adjacent and coextensive with the back surface of the substrate and away from a viewer observing the display surface through the substrate. The device provides uniform, high contrast illumination of underlying large area graphic displays such as maps, photographs, charts, and the like.
Inventors
- 👤 Robert Wragg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:32
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0033; G02B6/0035; G02B6/0036; G02B6/0038; G09; G09F; G09F13/00; G09F13/18; G09F2013/1804
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
157 words
A front-lit illumination panel for providing directional illumination to a display surface comprising: (a) an optically transparent substrate having first and second parallel opposing major surfaces, said first major surface having a multiplicity of irregular depressions therein; and (b) an optically transparent material having an index of refraction closely matching that of said substrate partially filling the depressions in said substrate so as to give each of said depressions a regular concave, meniscus shaped surface, each said depression thereby having gently sloping sides and a relatively shallow slope angle to said first major surface so that light from the interior of said substrate is selectively aimed through either said first or second major surface, the light exiting through said first major surface being directed toward a display surface co-extensive with and adjacent to said first major surface and the light exiting said second major surface being directed away from a viewer observing said display through said substrate.
Claim 2
Dependent Claim
157 words
A front-lit illumination panel for providing directional illumination to a display surface comprising: (a) an optically transparent substrate having first and second parallel opposing major surfaces, said first major surface having a multiplicity of irregular depressions therein; and (b) an optically transparent material having an index of refraction closely matching that of said substrate partially filling the depressions in said substrate so as to give each of said depressions a regular concave, meniscus shaped surface, each said depression thereby having gently sloping sides and a relatively shallow slope angle to said first major surface so that light from the interior of said substrate is selectively aimed through either said first or second major surface, the light exiting through said first major surface being directed toward a display surface co-extensive with and adjacent to said first major surface and the light exiting said second major surface being directed away from a viewer observing said display through said substrate.
Claim 3
Dependent Claim
65 words
The device of claim 1 wherein said light exiting through said first major surface is within the angle θ m -φ m and said light exiting said second major surface is within an angle θ m where: φ m =maximum slope angle of said depressions, and θ m =90°-sin -1 [n sin(ψ-φ m )] where n=index of refraction of said substrate, and ψ=sin -1 (1/n).
Claim 4
Dependent Claim
30 words
The device of claim 2 wherein said viewer observes said display at an angle V, where V is the supplement of angle θ m relative to said second major surface.
Claim 5
Dependent Claim
15 words
The device of claim 1 wherein said depressions in said first major surface are grooves.
Claim 6
Dependent Claim
13 words
The device of claim 4 wherein said grooves are oriented in pseudo-random directions.
Claim 7
Dependent Claim
27 words
The device of claim 4 wherein said grooves have a width W of 0.001 inch or less and an average intergroove spacing greater than five times W.
Claim 8
Dependent Claim
37 words
The device of claim 1 wherein said depressions are spaced apart by a distance which decreases with their distance from said end surface such that said display surface has substantially uniform illumination with distance from said edge.
Claim 9
Dependent Claim
18 words
The device of claim 2 wherein the maximum slope angle (φm) of said depressions is 3° or less.
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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) | 1986-02-14 | 1986-08-16 | 1987-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-14 | 1990-08-16 | 1991-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-14 | 1994-08-16 | 1995-02-15 | $7700.00 | Window Closed / Lapsed |