Patent US4937709A successfully refreshed from Google Patents.
US4937709A
Expired / Lapsed
US
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Back lighting device for a liquid crystal panel
Assignee: Tosoh Quartz Corp
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Filing: 1989-08-14
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Granted: 1990-06-26
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Expires: 2009-08-14
Abstract
Abstract A back lighting device for a liquid crystal display has a light scattering coating in the form of dots covering the light emitting surface of a photo-conductive plate. The coating covers 3-50% of the surface nearest an end thereof adjacent a linear light source and covers 80-100% of the surface farthest from the light source. The variation of the coating rate across the surface produces uniform distribution of emitted light from the back lighting device.
Inventors
- 👤 Eiichi Yanagi
- 👤 Takumi Fukunishi
- 👤 Osamu Shoji
- 👤 Naoki Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:21
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0065; G02B6/0033; G02B6/0035; G02B6/004; G02B6/0043; G02B6/0058; G02B6/0061; G02B6/0066; G02B6/007; G02B6/0071
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
152 words
A back light device for a liquid crystal panel comprising: a photo-conductive plate made of a transmissive material and having a light emitting surface; a linear light source provided close to at least one side end portion of said photo-conductive plate; one surface of said photo-conductive plate partially coated with a light scattering material having a refractive index higher than said transmissive material of said photo-conductive plate; a light reflecting plate covering said one surface of said photo-conductive plate partially coated with said light scattering material; and a light scattering plate provided on an opposite surface that is the light emitting surface of said photo-conductive plate, in which said photo-conductive plate is partially coated with said light scattering material so that a coating rate thereof is increased in proportion to x n , where x is a distance from the linear light source, and n is a number from 1.7 to 3.
Claim 2
Dependent Claim
152 words
A back light device for a liquid crystal panel comprising: a photo-conductive plate made of a transmissive material and having a light emitting surface; a linear light source provided close to at least one side end portion of said photo-conductive plate; one surface of said photo-conductive plate partially coated with a light scattering material having a refractive index higher than said transmissive material of said photo-conductive plate; a light reflecting plate covering said one surface of said photo-conductive plate partially coated with said light scattering material; and a light scattering plate provided on an opposite surface that is the light emitting surface of said photo-conductive plate, in which said photo-conductive plate is partially coated with said light scattering material so that a coating rate thereof is increased in proportion to x n , where x is a distance from the linear light source, and n is a number from 1.7 to 3.
Claim 3
Dependent Claim
184 words
A back light device for a liquid crystal panel comprising: a photo-conductive plate made of a transmissive material and having a light emitting surface; a linear light source provided close to at least one side end portion of said photo-conductive plate; one surface of said photo-conductive plate partially coated with a light scattering material having a refractive index higher than said transmissive material of said photo-conductive plate; a light reflecting plate covering said one surface of said photo-conductive plate partially coated with said light scattering material; and a light scattering plate provided on an opposite surface that is the light emitting surface of said photo-conductive plate, in which said photo-conductive plate is dot-like coated with said light scattering material so that a coating rate thereof becomes larger as a distance from said linear light source is larger, and in which said photo-conductive plate is partially coated with said light scattering material so that a coating rate thereof is increased in proportion to x n , where x is a distance from the linear light source, and n is a number from 1.7 to 3.
Claim 4
Dependent Claim
184 words
A back light device for a liquid crystal panel comprising: a photo-conductive plate made of a transmissive material and having a light emitting surface; a linear light source provided close to at least one side end portion of said photo-conductive plate; one surface of said photo-conductive plate partially coated with a light scattering material having a refractive index higher than said transmissive material of said photo-conductive plate; a light reflecting plate covering said one surface of said photo-conductive plate partially coated with said light scattering material; and a light scattering plate provided on an opposite surface that is the light emitting surface of said photo-conductive plate, in which said photo-conductive plate is dot-like coated with said light scattering material so that a coating rate thereof becomes larger as a distance from said linear light source is larger, and in which said photo-conductive plate is partially coated with said light scattering material so that a coating rate thereof is increased in proportion to x n , where x is a distance from the linear light source, and n is a number from 1.7 to 3.
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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) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |