US5064276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light source for planar illumination in liquid crystal device
Assignee: Hitachi Ltd
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Filing: 1989-06-30
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Granted: 1991-11-12
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Expires: 2009-06-30
Abstract
Abstract A light source device disposing light sources at both end faces of the transparent plate in which a surface of the transparent plate in the side of an observer (front surface) is formed as the inclined and curved surface in view of limiting reduction in quantity of light per unit area at the observing area being far from the light source within a certain level, the one surface of the transparent plate is formed as the rough surface to diffuse the incident light, the other surface of the transparent plate is formed as a mirror-surface, and a reflecting layer having a high lightness is disposed at the lower side of the transparent plate in order to provide sufficient luminance for observers.
Inventors
- 👤 Syuusuke Endo
- 👤 Naofumi Aoyama
- 👤 Toshihiko Yabuuchi
- 👤 Teruo Seki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:43
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; F; F21; F21V; F21V7/00; G02B; G02B27/00; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0033; G02B6/0035; G02B6/0045; G02B6/0046; G02B6/005; G02B6/0066; G02B6/0068; G02B6/0081; G02B6/0083
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
81 words
A light source device comprising, a transparent plate, a reflecting plate disposed adjacent a first surface of said transparent plate, and at least one light source disposed at each of first and second end faces of said transparent plate, a second surface of said transparent plate opposite said first surface, said second surface including an inclined and curved surface portion with a thinnest portion of said transparent plate at the center area of said transparent plate between the two end faces.
Claim 2
Dependent Claim
81 words
A light source device comprising, a transparent plate, a reflecting plate disposed adjacent a first surface of said transparent plate, and at least one light source disposed at each of first and second end faces of said transparent plate, a second surface of said transparent plate opposite said first surface, said second surface including an inclined and curved surface portion with a thinnest portion of said transparent plate at the center area of said transparent plate between the two end faces.
Claim 3
Dependent Claim
48 words
A light source device according to claim 1, wherein the shape of said inclined and curved surface portion of said second surface is expressed by an exponential function of the distance from said light sources and said shape is symmetrical about the center area between said light sources.
Claim 4
Dependent Claim
19 words
A light source device according to claim 1, wherein said thinnest part at the center area is almost flat.
Claim 5
Dependent Claim
19 words
A light source device according to claim 1, wherein a light diffusing surface is provided on said second surface.
Claim 6
Dependent Claim
36 words
A light source device according to one of claims 1 to 4, wherein a liquid crystal display panel is disposed on said second surface of said transparent plate to be used for liquid crystal display device.
Claim 7
Dependent Claim
30 words
A light source device according to one of claims 1 to 5, wherein one of said end faces of said transparent plate is provided with a plurality of light sources.
Claim 8
Dependent Claim
124 words
A light source device according to claim 2, wherein said exponential function is ##EQU2## where y is a distance from said first surface to said second surface, x is a distance from said first end face, L is a length of said transparent plate, H is the value of y at said first end face, h is the value of y at x being (L/2-d), d is a distance in said x direction of a flat portion of said second surface at the center area of said transparent plate between said light sources disposed at said two end faces, and n is an arbitrary positive number larger than unity, and said inclined and curved second surface is symmetrical with respect to x being L/2.
Claim 9
Dependent Claim
17 words
A light source device according to claim 4, wherein said light diffusing surface is a rough surface.
Claim 10
Dependent Claim
17 words
A light source device according to claim 1, wherein said transparent plate is made of acrylic resin.
Claim 11
Dependent Claim
19 words
A light source device according to claim 1, wherein a diffusing plate is disposed adjacent to said second surface.
Claim 12
Dependent Claim
32 words
A light source device according to claim 7, wherein said h is in the range of 0.5 to 3.0 mm and said d is in the range of 0.5 to 6.0 mm.
Claim 13
Dependent Claim
17 words
A light source device according to claim 4, wherein said light diffusing surface is a matted surface.
Claim 14
Dependent Claim
14 words
A light source device according to claim 8, wherein said rough surface has directivity.
References Cited (Backward Citations)
US4630895A
Cited
US4909604A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-11 | 1995-05-13 | 1995-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-11 | 1999-05-13 | 1999-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-11 | 2003-05-13 | 2003-11-12 | $7700.00 | Window Closed / Lapsed |