Pixel drive circuit of OLED (Organic Light Emitting Diode) display and drive method thereof

Abstract

The invention discloses a pixel drive circuit of an OLED (Organic Light Emitting Diode) display and a drive method thereof. The pixel circuit comprises a drive transistor, two switching transistors, a coupling capacitor, a storage capacitor and an OLED, wherein the drain electrode of the first switching transistor is connected with a data line, the grid electrode is connected with a first scanning control line, and the source electrode is connected with the end B of the coupling capacitor; the drain electrode of the second switching transistor is connected with the storage capacitor and the end A of the coupling capacitor, the grid electrode is connected with a second scanning control line, and the source electrode is connected with the drain electrode of the drive transistor and is connected with a power line through the OLED; and the grid electrode of the drive transistor is connected with the storage capacitor and the end A of the coupling capacitor, and the source electrode is grounded. The circuit can be used for effectively compensating the heterogeneity of threshold voltage of a thin film transistor and the degeneration of the cut-in voltage of the OLED to improve the picture brightness homogeneity of the OLED display screen.

Description

technical field [0001] The invention relates to a pixel driving technology of a light emitting diode display, in particular to a pixel driving circuit of a light emitting diode display and a driving method thereof. Background technique [0002] With the development of display technology, passive array OLED has been unable to meet the requirements of high resolution and large amount of information display. For large-screen high-resolution displays, active array drive methods are usually used. [0003] Currently, thin film transistors used in active array OLEDs mainly include hydrogenated amorphous silicon thin film transistors (a-Si:H TFT) and low temperature polysilicon thin film transistors (LTPS TFT). The threshold voltage of a-Si:H TFT will drift with the working time. To solve this problem, Jae-Hoon Lee et al. :H TFT and OLED for Active Matrix OLED" (IEEE ELECTRON DEVICE LETTERS, VOL.26, NO.12, DECEMBER 2005) once proposed a compensation circuit, the pixel drive circui...

AI Technical Summary

Problems solved by technology

Generally speaking, the current-programmed pixel driving circuit needs a long charging time when displaying low grayscale, which affects its use in large-screen high-resolution displays.

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