A pixel circuit, a display panel and a display device

Abstract

A pixel circuit, a display panel and a display device are used for improving the display luminance uniformity of a display area of the display panel. The pixel circuit comprises a driving sub-circuit (2), the first end (A) thereof being connected with a first reference voltage source (Vref1) through a power supply lead and the second end (B) thereof being connected with the first end of a light emitting device (D1); a charging sub-circuit (1), the output thereof being connected with the third end (C) of the driving sub-circuit (2), being used for charging the driving sub-circuit (2) before the driving sub-circuit (2) drives the light emitting device (D1) to emit light; and a compensation sub-circuit (3), the first end thereof being connected with the second end of the light emitting device (D1) and the second end thereof being connected with a second reference voltage source (Vref2), being used for compensating a voltage drop on the power supply lead of voltages provided to the driving sub-circuit (2) by the first reference voltage source (Vref1), and therefore the driving current for driving the light emitting device (D1) to emit light is unrelated to the attenuation amount.

Description

Technical field [0001] The present invention relates to the field of organic light emitting display technology, in particular to a pixel circuit, a display panel and a display device. Background technique [0002] Organic Light Emitting Diode (OLED) displays have attracted much attention because of their low power consumption, high brightness, low cost, wide viewing angle, and fast response speed, and have been widely used in the field of organic light emitting technology. [0003] The driving method of OLED display to drive the light-emitting device to display light is DC drive. Before driving the light-emitting device to emit light, charge the capacitor and write the data signal into the capacitor; when driving the light-emitting device to emit light, the capacitor discharges, and the capacitor discharge voltage determines the flow through The driving current of the driving transistor drives the light-emitting device to emit light. [0004] Generally, for a pixel circuit without a...

AI Technical Summary

Problems solved by technology

[0006] First of all, due to the structural inhomogeneity, as well as the inhomogeneity in electrical performance and stability of the multiple driving transistors used to drive the light-emitting devices on the backplane for displaying, the threshold voltage of each driving transistor V th Compared to the preset value V th0 Drift occurred

Secondly, the stability of the driving transistor will decrease when the driving transistor is turned on for a long time, and its threshold voltage V th value will also change

[0007] In addition, with the development of OLED size enlargement, the load on the signal line becomes larger correspondingly, the number of pixel circuits increases, and the same power supply (providing a high-level reference voltage V dd power supply) for different pixel circuits, because the voltage V dd The drop is more obvious with the increase of traces, so that the voltage V actually provided to each pixel circuit dd Differences

When the same data signal V is applied to each pixel circuit Data , due to V dd The value of the backplane display area is different, and the current flowing through each OLED in the backplane display area is not equal, resulting in uneven current on the backplane, resulting in uneven brightness of the image

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