Patent US3863246A successfully refreshed from Google Patents.
US3863246A
Expired / Lapsed
US
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Backlighted display apparatus for preventing direct viewing of light sources
Assignee: Collins Radio Co
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Filing: 1973-07-09
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Granted: 1975-01-28
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Expires: 1993-07-09
Abstract
Abstract Apparatus for providing backlighting of a display comprising the use of louvered material between a light source and the sides of a prism wherein the prism is utilized to transmit and direct light rays to the display surface. The use of the prism in some embodiments eliminates direct viewing of the light source through the louvered material.
Inventors
- 👤 James S Trcka
- 👤 David C Yeoman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:09
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133524; G02F1/1336; G09; G09F; G09F13/00; G09F13/04; G09F13/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
73 words
A device for use in backlighting a display comprising, in combination: prism means having two minor surfaces and one major surface; louvered material attached to said two minor surfaces of said prism; display material attached to said major surface of said prism means, light passing through the louvered material and said prism to said display material being diffused by defined areas of said display material and contrasting greatly with areas of no diffusion.
Claim 2
Independent Claim
73 words
A device for use in backlighting a display comprising, in combination: prism means having two minor surfaces and one major surface; louvered material attached to said two minor surfaces of said prism; display material attached to said major surface of said prism means, light passing through the louvered material and said prism to said display material being diffused by defined areas of said display material and contrasting greatly with areas of no diffusion.
Claim 3
Dependent Claim
72 words
Apparatus as claimed in claim 1 wherein the louvered material comprises at least one sheet of material having a plurality of generally parallel thin opaque louvers set in a transparent matrix at an angle to the faces of said sheet, said louvers being spaced with opposed edges of adjacent louvers at least contacting a single plane normal to said faces to prevent transmission of light striking said sheet perpendicular to said faces.
Claim 4
Dependent Claim
44 words
Apparatus as claimed in claim 1 wherein the display material is a nematic liquid crystal display device, the liquid crystal portion of the material providing the diffusion of light for viewing purposes, the louvered material providing the contrast with the liquid crystal display areas.
Claim 5
Dependent Claim
55 words
The apparatus of claim 1 comprising in addition: light source means positioned adjacent to said louvered material on the side opposite that attached to said prism whereby light is transmitted through the louvered material into the prism means whereby the direct light from said light source means is not visible within a defined display angle.
Claim 6
Dependent Claim
55 words
Apparatus as claimed in claim 4 wherein the combination of the prism means and the louvered material restricts light from said light source means passing through said louvered material, said prism means and the display material to the display surface thereof at less than the critical angle for the display surface of the display material.
Claim 7
Dependent Claim
81 words
Display apparatus comprising, in combination: prism means including at least first, second and third non-parallel surfaces; light source means positioned adjacent to said prism means; display means attached to at least one of said surfaces of said prism, said display means including a differential pattern of light diffusion and transparent areas defining the indicia to be displayed; and light controlling means intermediate said surfaces of said prism means and said light source means for passing light rays to said display means.
Claim 8
Dependent Claim
81 words
Display apparatus comprising, in combination: prism means including at least first, second and third non-parallel surfaces; light source means positioned adjacent to said prism means; display means attached to at least one of said surfaces of said prism, said display means including a differential pattern of light diffusion and transparent areas defining the indicia to be displayed; and light controlling means intermediate said surfaces of said prism means and said light source means for passing light rays to said display means.
Claim 9
Dependent Claim
47 words
Apparatus as claimed in claim 6 wherein the combination of said light controlling means and said prism means allows light to pass from said light source to said display means only at angles greater than the critical angle of reflection of the surface of the display means.
Claim 10
Independent Claim
100 words
The method of backlighting a display area comprising a diffusing indicia portion and an unlighted background comprising the steps of: controlling light direction from one or more sources; maintaining the control of direction such that the light source may not be viewed from the display area; and bonding a geometrically shaped light transmitting prism between the display area and the light source such that all light rays striking the display area at points other than The diffused indicia portion strike at an angle greater than the critical angle of incidence whereby no specular light is emitted from the display area.
Claim 11
Independent Claim
100 words
The method of backlighting a display area comprising a diffusing indicia portion and an unlighted background comprising the steps of: controlling light direction from one or more sources; maintaining the control of direction such that the light source may not be viewed from the display area; and bonding a geometrically shaped light transmitting prism between the display area and the light source such that all light rays striking the display area at points other than The diffused indicia portion strike at an angle greater than the critical angle of incidence whereby no specular light is emitted from the display area.
Claim 12
Independent Claim
43 words
The method of backlighting a display area comprising the single step of: controlling the direction of all light rays such that they strike the display area surface at an angle greater than the critical angle of incidence of the non-diffused indicia portions thereof.
Claim 13
Independent Claim
43 words
The method of backlighting a display area comprising the single step of: controlling the direction of all light rays such that they strike the display area surface at an angle greater than the critical angle of incidence of the non-diffused indicia portions thereof.
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) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |