Driving method for a thin-film electroluminescent element of a three-layer construction
US3975661A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 1974 |
| Grant date | Aug 17, 1976 |
| Priority date | — |
| Expiry date | Jun 19, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Disclosed is a driving method for a thin-film electroluminescent element of a three-layer construction which emits light and exhibits the hysteresis phenomenon within the light emission versus applied voltage characteristics. The light intensity is maintained and memorized at a predetermined value in the element by the application of a train of sustaining pulses of alternating voltage, the amplitude thereof being chosen at the voltage level appearing at the point in the hysteresis loop characteristics where the difference between the maximum light brightness on the voltage decreasing curve and the minimum light brightness on the voltage increasing curve is considerably large. The sustaining light brightness is controlled by varying the amplitude or the pulse width of the sustaining pulses. The information may be written, memorized and eliminated in the EL element as variations of the light brightness. To write or eliminate the information in the EL element, it is also effective to utilize external light excitation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.