Patent US4808880A successfully refreshed from Google Patents.
US4808880A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display means with memory effect comprising thin electroluminescent and photoconductive films
Assignee: France Telecom R&D SA
•
Filing: 1985-12-11
•
Granted: 1989-02-28
•
Expires: 2005-12-11
Abstract
Abstract An electroluminescent display with a memory effect. The display includes an electroluminescent layer and a photoconductive layer, both of which are thin films of approximately 1 micron. The two layers are placed between two systems of electrodes which are connected to a power source. Thin dielectric film may also be part of the assembly.
Inventors
- 👤 Pascal Thioulouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:20
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G3/30; G09G2300/00; G09G2300/08; G09G2300/088; G09G2300/0885; G09G2360/00; G09G2360/14; G09G2360/145; G09G2360/147; G09G2360/148
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
83 words
Electroluminescent display means with a memory effect comprising, on an insulating support (40), an electroluminescent film (44) and a photoconductive film (46) stacked on one another, the assembly of said two films being placed between two systems of electrodes (42, 48), the latter being connected to an electric power source (50) permitting the excitation of certain zones of the electroluminescent film, characterized in that the electroluminescent film (44) and the photoconductive film (46) are thin films having a thickness of approximately 1 micron.
Claim 2
Dependent Claim
83 words
Electroluminescent display means with a memory effect comprising, on an insulating support (40), an electroluminescent film (44) and a photoconductive film (46) stacked on one another, the assembly of said two films being placed between two systems of electrodes (42, 48), the latter being connected to an electric power source (50) permitting the excitation of certain zones of the electroluminescent film, characterized in that the electroluminescent film (44) and the photoconductive film (46) are thin films having a thickness of approximately 1 micron.
Claim 3
Dependent Claim
23 words
Means according to claim 1, characterized in that the electroluminescent film is a stack of a thin electroluminescent film and thin dielectric films.
Claim 4
Dependent Claim
21 words
Means according to claim 2, characterized in that the photoconductive film is placed between the electroluminescent film and a dielectric film.
Claim 5
Dependent Claim
23 words
Means according to claim 3, characterized in that an additional thin dielectric film is placed between the photoconductive film and the electroluminescent film.
Claim 6
Dependent Claim
58 words
Means according to claim 1, characterized in that an optical excitation initially making the photoconductive material conductive is obtained by the light emitted by the thin electroluminescent film, which is itself under the effect of an adequate electrical excitation applied to the two systems of electrodes, so that the addressing of the means is all electric (52C, 52L).
Claim 7
Dependent Claim
15 words
Means according to claim 1, characterized in that the photoconductive material is hydrogenated amorphous silicon.
Claim 8
Dependent Claim
16 words
Means according to claim 1, characterized in that the photoconductive film is CdS, CdSe or ZnO.
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) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |