Method of improving the memory effect and brightness of an alternating current excited thin film electroluminscent device
US4275336A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1979 |
| Grant date | Jun 23, 1981 |
| Priority date | — |
| Expiry date | Mar 5, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for improving the memory effect and brightness of an alternating current (AC) excited thin film electroluminensence (ACTEL) device is described. A typical ACTEL device has a thin luminescent layer made of ZnS thin film doped with Mn which is sandwiched between two dielectric layers. ACTEL devices exhibit a brightness versus voltage amplitude hysteresis loop which is commonly referred to as the memory effect. The application of a hybrid AC excitation waveform to the ACTEL device provides increased brightness and improved memory effect stability. The hybrid waveform has an initial portion that is sufficiently high for efficient carrier generation and a remaining waveform portion that is at a lower level than the initial portion for charge collection and holding purposes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.