Pixel circuit and display device

Abstract

The invention provides a pixel circuit and a display device, which belong to the technical field of display. The pixel circuit of the present invention includes: an initialization unit for inputting the first reference voltage to the node A under the control of the enable signal, and controlling the driving transistor to turn on, so that the first power supply voltage discharges the node B through the driving transistor The threshold voltage extraction unit is used to charge the node C through the voltage written to the node B, so as to extract and save the threshold voltage of the driving transistor; wherein, the voltage of the node B is the second power supply voltage through the driving transistor to the node B. The voltage for charging; the switch unit is used to write the data voltage signal into the node C under the control of the scan signal; the driving transistor is used to drive the light-emitting device to emit light; the feedback compensation unit is used for the light-emitting device in the light-emitting stage. The current is sampled to generate a data voltage compensation signal for the next frame of display to compensate the data voltage.

Description

technical field [0001] The invention belongs to the field of display technology, and in particular relates to a pixel circuit and a display device. Background technique [0002] OLED (Organic Light-Emitting Diode): Organic Light-Emitting Diode is also called Organic Light-Emitting Diode, Organic Light-Emitting Semiconductor. It was discovered in the laboratory by Chinese-American professor Ching W.Tang in 1979. OLED display technology has the advantages of self-illumination, wide viewing angle, almost infinitely high contrast, low power consumption, and extremely high response speed. [0003] At present, no matter whether Low Temperature Poly Silicon (LTPS; low temperature polysilicon) or a-Si is used as the switch tube of the display device, there are inconsistencies in the threshold voltage, carrier mobility and series resistance of the TFT, resulting in LTPS TFT and a- The dispersion of Si TFT characteristics, the different threshold voltages of TFTs in the entire panel...

AI Technical Summary

Problems solved by technology

[0003] At present, no matter whether Low Temperature Poly Silicon (LTPS; low temperature polysilicon) or a-Si is used as the switch tube of the display device, there are inconsistencies in the threshold voltage, carrier mobility and series resistance of the TFT, resulting in LTPS TFT and a- The dispersion of Si TFT characteristics, the different threshold voltages of TFTs in the entire panel will cause differences in the turn-on level of each TFT tube. In the saturation region, the threshold voltages are different, resulting in differences in current output and uneven OLED display. In addition, for Low-amplitude signal level, in high-resolution products, when driving the switch tube, the switch tube will not be turned on in time due to the long charging time of the storage capacitor, and there will be abnormal display. After the threshold voltage of the switching tube, the signal conduction time is extremely short, and in extreme cases, there will also be abnormal display problems. At present, there are many solutions to solve the problem of abnormal display caused by the slow charging time of low pixels and the different threshold voltages of the switching tubes. , such as 3T1C, 4T2C, 5T1C, 6T1C, 7T1C, 8T2C and other internal compensation circuits, each compensation circuit aims at different improvement points, such as pixel internal threshold compensation, IR drop compensation, etc., and the current compensation scheme research is more It is based on the improvement of the threshold shift of the turn-on voltage of the light-on tube. For OLED itself as a diode device, the impact of its own voltage threshold shift on the display

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