Patent EP0228288A2 successfully refreshed from Google Patents.
EP0228288A2
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EP
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Light box
Assignee: General Electric Co
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Filing: 1986-12-23
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Granted: —
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Expires: 2006-12-23
Abstract
Abstract A light box comprises a source of light (12), a reflector (14) and a Fresnel lens (38). The lens (38) provides nearly constant illumination of an object such as a liquid crystal cell (50) by collimating light parallel to a normal to the cell. Thus the cell (50) will exhibit a nearly uniform electro-optical response. The reflector (14) preferably is parabolic, while the light source (12) preferably is a line source such as a flourescent tube.
Inventors
- 👤 Richard William Nosker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 08:56
CPC Classifications
F; F21; F21V; F21V13/00; F21V13/02; F21V13/04; G; G02; G02B; G02B19/00; G02B19/0004; G02B19/0028; G02B19/0033; G02B19/0047; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133526
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
33 words
A light box comprising: a source of light (12); a reflector (14) disposed adjacent said source and having an aperture (16); and a Fresnel lens (38) disposed adjacent said aperture of said reflector.
Claim 2
Dependent Claim
33 words
A light box comprising: a source of light (12); a reflector (14) disposed adjacent said source and having an aperture (16); and a Fresnel lens (38) disposed adjacent said aperture of said reflector.
Claim 3
Dependent Claim
17 words
A light box according to claim 1 wherein said source of light (12) comprises a line source.
Claim 4
Dependent Claim
15 words
A light box according to claim 2 wherein said line source comprises a flourescent tube.
Claim 5
Dependent Claim
20 words
A light box according to any one of the preceding claims wherein said reflector (14) comprises a cylindrical parabolic reflector.
Claim 6
Dependent Claim
19 words
A light box according to any one of the preceding claims wherein said lens (38) comprises an acrylic plastic.
Claim 7
Dependent Claim
12 words
A light box according to claim 5 wherein said plastic comprises poly(methylmethacrylate).
Claim 8
Dependent Claim
27 words
A light box according to any one of the preceding claims wherein said lens (38) substantially collimates light from said source and said reflector in one plane.
Claim 9
Dependent Claim
76 words
A light box according to any one of the preceding claims in which, at a plurality of points on the lens (38), light from the light source (12) strikes the lens (38) with more than one direction of incidence, and the lens (38) acts so that at each said point light leaves at more than one direction of departure, the directions of departure being to either side of a predetermined direction common to each said point.
Claim 10
Dependent Claim
21 words
A light box according to claim 8 in which the said directions of departure are equidistant from the said predetermined direction.
Claim 11
Dependent Claim
73 words
A display comprising: a source of light (12); a reflector (14) disposed adjacent said source (12) and having an aperture (16) ; a Fresnel lens (38) disposed adjacent the aperture of said reflector; means (48) for polarizing light disposed adjacent said lens (38); means (50) for changing the polarization of light disposed adjacent said polarizing means (48); and means (52) for analyzing the polarization of light passing through said polarization changing means (50).
Claim 12
Dependent Claim
73 words
A display comprising: a source of light (12); a reflector (14) disposed adjacent said source (12) and having an aperture (16) ; a Fresnel lens (38) disposed adjacent the aperture of said reflector; means (48) for polarizing light disposed adjacent said lens (38); means (50) for changing the polarization of light disposed adjacent said polarizing means (48); and means (52) for analyzing the polarization of light passing through said polarization changing means (50).
Claim 13
Dependent Claim
30 words
A display according to claim 10 wherein said lens (38)collimates light in a direction parallel to a normal to a surface through which light enters said polarization changing means (50).
Claim 14
Dependent Claim
24 words
A display according to claim 10 or claim 11 wherein said polarizing means (48) and said analyzing means (52) each comprise a sheet polarizer.
Claim 15
Dependent Claim
22 words
A display according to any one of claims 10 to 12 wherein said polarization changing means (50) comprises a liquid crystal cell.
Claim 16
Dependent Claim
16 words
A display according to claim 13 wherein said cell includes a twisted nematic liquid crystal material.
Claim 17
Dependent Claim
23 words
A display according to any one of claims 10 to 14 further comprising means (54) for diffusing light disposed adjacent said analyzing means.
Claim 18
Dependent Claim
16 words
A display according to claim 15 wherein said diffusing means (54) comprises a cylindrical lenticular array.
References Cited (Backward Citations)
No citation records indexed.
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