US5575549A
Expired / Lapsed
US
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Surface light source device
Assignee: Enplas Corp
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Filing: 1994-08-12
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Granted: 1996-11-19
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Expires: 2014-08-12
Abstract
Abstract A surface light source device using a light conducting member, in which a multiplicity of concave portions are formed on an opposite surface of a light emitting surface of the light conducting member and the concave portions are arranged to have specific shapes to obtain a bright surface light source with a uniform brightness. A light diffusing material is fulfilled within the concave portions of the light conducting member so that a more uniform brightness can be obtained in an easy manner.
Inventors
- 👤 Tsuyoshi Ishikawa
- 👤 Kayoko Watai
- 👤 Kazuaki Yokoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:35
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0013; G02B6/0023; G02B6/0025; G02B6/0033; G02B6/0035; G02B6/0038; G02B6/005; G02B6/0051; G02B6/0058; G02B6/0061; G02B6/0045; G02B6/0046; G02B6/0055; G02B6/0066; G02B6/0068
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
A surface light source device comprising a light conducting member made of transparent material, a linear light source disposed in the vicinity of one of edge surfaces of said light conducting member, a diffusion plate disposed on a light emitting surface side of said light conducting member, and a reflective member disposed on an opposite side surface of said light emitting surface of said light conducting member, said light conducting member comprising a multiplicity of conical or polygonal pyramid-shaped concave portions formed on said opposite side surface of the light conducting member and said concave portions satisfy the following conditions: 80°≦α≦100° 90°>β>90°-θ wherein the reference symbol α represents a top angle of the concave portion, β represents an inclined angle of an inclined surface of the concave portion on a linear light source side, and θ is a value given by the following formula 1a when a refractive index of said light conducting member is represented by n: θ=sin.sup.-1 (1/n).
Claim 2
Dependent Claim
160 words
A surface light source device comprising a light conducting member made of transparent material, a linear light source disposed in the vicinity of one of edge surfaces of said light conducting member, a diffusion plate disposed on a light emitting surface side of said light conducting member, and a reflective member disposed on an opposite side surface of said light emitting surface of said light conducting member, said light conducting member comprising a multiplicity of conical or polygonal pyramid-shaped concave portions formed on said opposite side surface of the light conducting member and said concave portions satisfy the following conditions: 80°≦α≦100° 90°>β>90°-θ wherein the reference symbol α represents a top angle of the concave portion, β represents an inclined angle of an inclined surface of the concave portion on a linear light source side, and θ is a value given by the following formula 1a when a refractive index of said light conducting member is represented by n: θ=sin.sup.-1 (1/n).
Claim 3
Dependent Claim
57 words
A surface light source device according to claim 1, wherein said opposite side surface of said light conducting member disposed on the reflecting member side is inclined such that a thickness of said light conducting member is the largest at the edge surface on the light source side and becomes smaller as farther from the light source.
Claim 4
Dependent Claim
45 words
A surface light source device according to claim 1, wherein said light conducting member is arranged as a plate-like member where a light emitting surface thereof and an opposite surface of the light emitting surface are arranged as plane surfaces being parallel to each other.
References Cited (Backward Citations)
JPH0331782A
Cited
JPH03189679A
Cited
JPH0594802A
Cited
US5420761A
Cited
US5461547A
Cited
US5485354A
Cited
US5485291A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-19 | 2000-05-20 | 2000-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-19 | 2004-05-20 | 2004-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-19 | 2008-05-20 | 2008-11-19 | $7700.00 | Window Closed / Lapsed |