US4933814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Planar luminescent device
Assignee: Mitsubishi Electric Corp
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Filing: 1989-01-23
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Granted: 1990-06-12
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Expires: 2009-01-23
Abstract
Abstract A planar luminescent device comprising a light source whose luminance distribution exhibits varied luminous intensity from a high level to a low level, a light transmitting plate having a light transmitting property and shaped in a planar form, and a reflecting frame for enclosing the light source in cooperation with the surface of a printed board to which the light source is attached and the end face of the light transmitting plate and also holding the light transmitting plate having its end faces on which the light from the light source does not impinge in close contact therewith, in which a portion on an end face of the light transmitting plate is disposed closest to the position where the luminance of the light source is at the low level and incident light on the end face is adapted to be scatteringly reflected by a scattering reflection layer disposed on the back face of the light transmitting plate and radiated from the surface of the same.
Inventors
- 👤 Yukiharu Sanai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:00
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0013; G02B6/0023; G02B6/0031; G02B6/0081; G09; G09F; G09F13/00; G09F13/04; G09F13/0409; G02B6/0083; G02B6/0086; G02B6/0088; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
111 words
A planar luminescent device comprising a light source whose luminance distribution exhibits varied luminous intensity from a high level to a low level and a light transmitting plate having a light transmitting property and shaped in a planar form, wherein a portion on an end face of said light transmitting plate is disposed closest to a position where the luminance of said light source is at the low level and incident light on said end face is adapted to be scatteringly reflected by a scattering reflection layer disposed on a back face of said light transmitting plate and radiated from a surface opposite said back face of said light transmitting plate.
Claim 2
Dependent Claim
111 words
A planar luminescent device comprising a light source whose luminance distribution exhibits varied luminous intensity from a high level to a low level and a light transmitting plate having a light transmitting property and shaped in a planar form, wherein a portion on an end face of said light transmitting plate is disposed closest to a position where the luminance of said light source is at the low level and incident light on said end face is adapted to be scatteringly reflected by a scattering reflection layer disposed on a back face of said light transmitting plate and radiated from a surface opposite said back face of said light transmitting plate.
Claim 3
Dependent Claim
47 words
A planar luminescent device according to claim 1, wherein said light source is an incandescent lamp having a filament wherein the filament of said incandescent lamp is disposed perpendicular to the end face of said light transmitting plate on which the light from said incandescent lamp impinges.
Claim 4
Dependent Claim
68 words
A planar luminescent device according to claim 1, further comprising a reflecting frame for enclosing said light source in cooperation with a surface of a printed board to which said light source is attached and the end face of said light transmitting plate and also holding said light transmitting plate having its end on which the light from said light source does not impinge in close contact therewith.
Claim 5
Dependent Claim
43 words
A planar luminescent device according to claim 3, wherein portions of said reflecting frame apart from said light source are meeting at an angle of 45° with the end face of said light transmitting plate on which light reflected by said portions impinges.
Claim 6
Dependent Claim
24 words
A planar luminescent device according to claim 4, wherein said planar luminescent device is disposed at a back of a liquid crystal display panel.
Claim 7
Dependent Claim
23 words
A planar luminescent device according to claim 5, wherein said light source is disposed at the back of the liquid crystal display panel.
Claim 8
Dependent Claim
24 words
A planar luminescent device according to claim 3, wherein said planar luminescent device is disposed at a back of a liquid crystal display panel.
Claim 9
Dependent Claim
23 words
A planar luminescent device according to claim 7, wherein said light source is disposed at the back of the liquid crystal display panel.
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) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |