TFT pixel threshold voltage compensation circuit with global compensation
US11011113B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 2020 |
| Grant date | May 18, 2021 |
| Priority date | — |
| Expiry date | Mar 26, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2330/021
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A pixel circuit compensates the threshold voltage variations of the drive transistor with an ultra-short one horizontal (1H) time, with additionally removing the possible memory effects associated with the light-emitting device and the drive transistor from the previous frame. An ultra-short 1H time (<2 μs) is achieved via separation of threshold compensation of the drive transistor and data programming phases. The pixel circuit has a two-capacitor configuration, whereby a first capacitor is used for drive transistor threshold compensation, and a second capacitor is used to store the data voltage during a data pre-loading phase. Two transistors are employed to electrically connect the gate and source of the drive transistor to a common initialization voltage during an initialization phase to reset circuit voltages for the current frame. In this manner, no current flows through the drive transistor to the light-emitting device during the initialization phase when the light-emitting device does not emit light, which saves power. An array of individual pixel circuits is controlled using a global compensation scheme in which global control signals are applied to the individual pixel ci…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.