Light emissive active matrix display devices with optical feedback effective on the timing, to counteract ageing
US7502001B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 2004 |
| Grant date | Mar 10, 2009 |
| Priority date | — |
| Expiry date | Jul 25, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10K59/13
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an active matrix display, each pixel has a storage capacitor for storing a voltage to be used for addressing a drive transistor. A discharge transistor is provided for discharging the storage capacitor thereby to switch off the drive transistor. The timing of this is controlled by a light-dependent device which is illuminated by the display element. The drive transistor is controlled to provide a constant light output from the display element, and the duration is controlled in dependence on the data voltage. Optical feedback is used to alter further the timing of operation of the discharge transistor to provide ageing compensation of the display element and compensation for changes in the drive transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.