Compensation method for ovss voltage drop of oled display device and pixel driving circuit

Abstract

The invention provides a method for compensating the OVSS voltage drop of an OLED display device and a pixel driving circuit. In the compensation method, a first pixel driving circuit with the function of detecting OVSS voltage is arranged in some sub-pixels of the OLED display device, and then the first pixel driving circuit is used to detect the OVSS voltage of these sub-pixels, and to detect The obtained OVSS voltages of these sub-pixels are based on the OVSS voltages of all sub-pixels of the OLED display device obtained by interpolation, and then the OVSS voltage compensation lookup table is obtained according to the OVSS voltages of all sub-pixels of the OLED display device Finally, the data signal voltage is compensated by the OVSS voltage compensation lookup table, and then the compensated data signal voltage is used to drive the OLED display device for screen display, which can effectively compensate the voltage drop of the OVSS voltage in the OLED display device and improve the display brightness of the OLED display device uniformity.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a method for compensating the OVSS voltage drop of an OLED display device and a pixel driving circuit. Background technique [0002] Organic light emitting diode (Organic Light Emitting Display, OLED) display device has self-illumination, low driving voltage, high luminous efficiency, short response time, high definition and contrast, nearly 180° viewing angle, wide operating temperature range, and can realize flexible display and With many advantages such as large-area full-color display, it is recognized by the industry as a display device with the most potential for development. [0003] According to the driving mode, OLEDs can be divided into two types: passive driving and active driving, that is, direct addressing and thin film transistor (Thin Film Transistor, TFT) matrix addressing. Among them, active driving is also called active matrix (ActiveMatrix, AM) type, and each...

AI Technical Summary

Problems solved by technology

Inevitably, the OVSS voltage will generate a voltage drop (IR Drop) on the wire, and the resistance value of the wire makes the OVSS voltage obtained by each pixel drive circuit different, so that under the same data signal voltage input, different pixels have different current and brightness output, resulting in uneven display brightness of the entire panel

[0005] Specifically, see figure 1 , an existing AMOLED display device includes: a substrate 10, a plurality of sub-pixels arranged in an array on the substrate 10, and a plurality of OVSS wirings arranged in parallel and spaced apart on the substrate 10 20, each row of sub-pixels is electrically connected to one OVSS wiring 20 and the corresponding OVSS wiring 20 provides an OVSS voltage, and the OVSS voltage is input from both ends of the OVSS wiring 20 located at the edge of the substrate 10 to the In the OVSS wiring 20, due to the voltage drop caused by the resistance of the OVSS wiring 20, the actual voltage in the middle of the OVSS wiring 20 is smaller than the voltage input at both ends of the OVSS wiring 20, that is, the sub-substrate located in the middle of the substrate 10. The OVSS voltage received by the pixel is lower than the OVSS voltage received by the sub-pixels located at both ends of the substrate 10, which eventually leads to uneven display brightness of the entire panel

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