Pixel circuit and driving method thereof, display panel and display device

Abstract

The invention provides a pixel circuit and a driving method thereof, a display panel and a display device. The pixel circuit comprises eight transistors, two storage capacitors and an organic light emitting device (OLED), a threshold voltage of the first transistor is compensated through mutual cooperation of the transistors and the capacitors, a driving current for driving the OLED to emit lightis made to be independent of the threshold voltage of the first transistor, so influence of fluctuation of the threshold voltage of the first transistor on the OLED is avoided, a problem of uneven display brightness caused by this is solved, the display effect of the whole frame is improved, moreover, since the leakage current between the first storage capacitor and the second storage capacitor can be reduced by the eighth transistor, reduction of a gate voltage of the first transistor is avoided, a problem of scintillation caused by the leakage current is solved, and the display effect of thewhole display frame is further improved.

Description

technical field [0001] The present invention relates to the technical field of flat panel display, in particular to a pixel circuit and a driving method thereof, a display panel and a display device. Background technique [0002] Organic Light Emitting Diode (OLED) is one of the hot spots in the field of display research today. Compared with Liquid Crystal Display (LCD), OLED has the advantages of low energy consumption, low production cost, self-luminescence, wide viewing angle and The advantages of fast response and so on. At present, OLED displays have begun to replace traditional LCD displays in display fields such as mobile phones, PDAs, and digital cameras. Among them, pixel circuit design is the core technical content of OLED displays, which has important research significance. [0003] Unlike LCD, which uses a stable voltage to control brightness, OLED is current-driven and requires a stable current to control light emission. Due to reasons such as process and dev...

AI Technical Summary

Problems solved by technology

Due to the process and device aging, there will be non-uniformity in the threshold voltage of the driving transistor of the pixel circuit, which will cause the current flowing through different OLED pixels to change, resulting in uneven display brightness, thereby affecting the display effect of the entire image.

[0004] At present, this problem is mainly solved through the internal compensation function of the pixel circuit. Generally, the internal compensation of the pixel circuit can be realized only through the pixel circuit with compensation function. The pixel circuit is generally a 7T1C (7 transistors and 1 capacitor) circuit. However, in the data writing stage of the 7T1C circuit, due to the characteristics of the transistor itself, a small current will still flow when it is turned off, which reduces the gate voltage of the driving transistor, making the brightness of the organic light-emitting element change with time, forming a flickering problem

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