OLED (Organic Light Emitting Diode) pixel structure for compensating light emitting nonuniformity and driving method

Abstract

The invention provides an organic light emitting display pixel structure and a driving method thereof. The pixel structure comprises first to fifth thin film transistors, a capacitor and an OLED (Organic Light Emitting Diode) device, wherein the width to length ratio of the first thin film transistor is set to compensate the brightness loss caused by degradation of the OLED device. According to the pixel structure, the following steps are performed in the process of refreshing each frame image: in a precharging period, a scan line and a first control signal (EM) have low levels, and a second control signal (EMD) has a high level; in a compensating period, the scan line has a low level, and the first control signal (EM) and the second control signal (EMD) have high levels; and in a light emitting period, the scan line has a high level, and the first control signal (EM) and the second control signal (EMD) have low levels.

Description

technical field [0001] The invention relates to a pixel structure of an organic light-emitting display device, which can compensate for the non-uniform luminescence caused by the degradation of the OLED device, the non-uniformity of the threshold voltage of the TFT drive tube, and the voltage drop (IRdrop) of the backplane power supply. The present invention also relates to a method for driving the above-mentioned pixel structure. Background technique [0002] Organic light-emitting display diodes (OLEDs), as a current-mode light-emitting device, have been increasingly used in high-performance displays. With the increase of the display size, the traditional passive matrix organic light emitting display device (Passive Matrix OLED) requires a shorter driving time of a single pixel, so it needs to increase the transient current and increase the power consumption. At the same time, the application of high current will cause the voltage drop on the ITO line to be too large, and...

AI Technical Summary

Problems solved by technology

Since the voltage of ARVDD is related to the current, IR Drop will also cause the current difference in different regions, and then produce mura when displaying

[0006] Third, the uneven film thickness of OLED devices will also cause non-uniformity in electrical properties during evaporation.

Figure 8 structure can compensate V TH The effects of non-uniformity, IR drop and OLED degradation, but because it is a current drive, it is not suitable for large-size panel applications

[0014] It can be seen that no effective means to solve the aforementioned technical problems has been proposed in the prior art, that is, how to solve the degradation of the OLED device, the non-uniformity of the threshold voltage of the TFT drive tube, and the luminescence caused by the voltage drop (IR drop) of the backplane power supply. Compensate for unevenness

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