Pixel unit circuit, working method therefore and organic light emitting diode (OLED) display device

Abstract

The invention discloses a pixel unit circuit, which consists of a first sub-circuit module, a second sub-circuit module, a capacitor and an organic light emitting diode (OLED). The main working process of the pixel unit circuit is divided into a compensation stage and an evaluation stage. Compared with the traditional pixel unit circuit, the pixel unit circuit is characterized in that the degeneration of the OLED device, the threshold voltage heterogeneity of a thin film transistor (TFT) driving pipe and the IR drop of a rear panel power supply can be effectively compensated. In addition, because the pixel unit circuit provided by the invention is designed on the basis of the voltage feedback technology, the pixel unit circuit is suitable to apply to a big-size panel. In addition, the invention also correspondingly discloses a working method for the pixel unit circuit and an OLED display device comprising a plurality of pixel unit circuits connected in series.

Description

technical field [0001] The present invention relates to pixel circuit design technology, in particular to a pixel unit circuit and its working method, and an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display device. Background technique [0002] OLED, as a current-mode light-emitting device, has been increasingly used in high-performance displays. With the increase of display size, traditional passive matrix organic light-emitting diode (Passive Matrix OLED, PMOLED) displays require shorter driving time of a single pixel, so it is necessary to increase the transient current and increase power consumption. At the same time, high-current The application will cause an excessive voltage drop on the indium tin oxide (ITO) line, and make the OLED operating voltage too high, thereby reducing the efficiency of the OLED, and the active matrix organic light-emitting diode (Active Matrix OLED, AMOLED) display through the progressive scan input of the switch tube...

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 the mura phenomenon when displaying;

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

It can be seen from the above formula that if the V between different pixel units th different, there is a difference in current

And as the OLED device degrades, even if a constant current is provided, the luminous brightness of the OLED will decrease

[0013] present, the compensation V th There are many types of pixel unit structures for uniformity and IR drop, but some pixel unit structures can compensate for the V of the drive tube th Non-uniformity, but it cannot compensate the brightness loss caused by IR Drop and OLED degradation; although some pixel unit circuits can compensate the V of the drive tube th Non-uniformity and IR Drop, but cannot compensate for brightness loss caused by OLED degradation; although some pixel unit circuits can compensate for V th Non-uniformity, IR drop, and OLED degradation, but because the structure is current-driven, it is not suitable for large-size panel applications; although some pixel unit circuits can compensate for the impact of OLED degradation, they cannot compensate for V th Non-uniformity and IR Drop

Therefore, the pixel circuit proposed in the prior art cannot effectively compensate the threshold voltage V of the TFT drive tube. th In addition to the effects of non-uniformity, IRdrop of backplane power supply and OLED degradation, it is also suitable for large-size panel applications

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