US4500173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electroluminescent lamp for liquid crystal display
Assignee: Timex Group USA Inc
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Filing: 1983-05-02
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Granted: 1985-02-19
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Expires: 2003-05-02
Abstract
Abstract A backlighted liquid crystal display is disclosed which includes an electroluminescent backlight having a reduced amount of phosphor acting as both a source of light for viewing the display during nighttime hours and as a light diffuser for viewing the display during daytime hours. The electroluminescent backlight is made thinner while the phosphor content is optimally reduced to provide a backlight that improves the viewability of the display especially during daytime hours without the need of a transflector. Wherein the minimal amount of phosphor is dispersed in a binder in the electroluminescent layer is substantially 1 volume unit of phosphor for every 4 to 5 volume units of binder.
Inventors
- 👤 Marshall Leibowitz
- 👤 Douglas A. George
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:27
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/133602; G02F1/133603; Y; Y10; Y10S; Y10S428/00; Y10S428/917
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
An improved combination electroluminescent backlight and incident light reflector for a liquid crystal display for nighttime and daytime viewing, respectively, the improvement comprising: a liquid crystal display a light-reflective electrode in said electroluminescent backlight arranged to reflect incident light entering and passing through said liquid crystal display, and a thin electroluminescent layer in said electroluminescent backlight between said light-reflective electrode and said liquid crystal display having a minimal amount of phosphor selected to provide for light diffusion for improving daytime viewability of said liquid crystal display as well as to provide a light source for improving nighttime viewability of said crystal display, in which said minimal amount of phosphor is dispersed in a binder in said electroluminescent layer in substantially one volume unit of phosphor for every four to five volume units of binder.
Claim 2
Dependent Claim
134 words
An improved combination electroluminescent backlight and incident light reflector for a liquid crystal display for nighttime and daytime viewing, respectively, the improvement comprising: a liquid crystal display a light-reflective electrode in said electroluminescent backlight arranged to reflect incident light entering and passing through said liquid crystal display, and a thin electroluminescent layer in said electroluminescent backlight between said light-reflective electrode and said liquid crystal display having a minimal amount of phosphor selected to provide for light diffusion for improving daytime viewability of said liquid crystal display as well as to provide a light source for improving nighttime viewability of said crystal display, in which said minimal amount of phosphor is dispersed in a binder in said electroluminescent layer in substantially one volume unit of phosphor for every four to five volume units of binder.
Claim 3
Dependent Claim
39 words
The improved combination electroluminescent backlight and incident light reflector of claim 1 in which said minimal amount of phosphor is dispersed in a binder in said electroluminescent layer in substantially the volume to volume ratio of 1 to 4.
Claim 4
Dependent Claim
54 words
The improved combination electroluminescent backlight and incident light reflector to claim 2 in which said phosphor in said electroluminescent layer is selectively activated by an applied voltage produced by an electronic circuit means, and also selectively serves as a diffuser for light reflected from said light-reflective electrode when the electroluminescent layer is not activated.
Claim 5
Dependent Claim
19 words
The improved combination electroluminescent backlight and incident light reflector of claim 1 in which said light-reflective electrode is metal.
Claim 6
Dependent Claim
18 words
The improved combination electroluminescent backlight and incident light reflector of claim 4 in which said metal is aluminum.
Claim 7
Dependent Claim
19 words
The improved combination backlight and incident light reflector of claim 1, in which said binder is transparent epoxy resin.
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) | 1988-02-19 | 1988-08-20 | 1989-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-19 | 1992-08-20 | 1993-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-19 | 1996-08-20 | 1997-02-19 | $7700.00 | Window Closed / Lapsed |