Pixel Compensation for OLED Display Stripes
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Solution Overview
Problem
Aging driving transistors in electroluminescent display panels cause shifts in threshold voltages and mobility, leading to differences in display brightness, and existing compensation methods are inaccurate due to coupling capacitance effects, resulting in display quality issues like horizontal stripes.
Innovation Solution
A pixel compensation method and apparatus that charge detection lines for sub-pixels in alternating rows with non-zero and zero grayscale data voltages during blanking periods, calculate voltage differences to determine accurate detected voltages, and compensate sub-pixels in the next frame, thereby eliminating the influence of coupling capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing compensation methods are used to compensate for transistor aging, then compensation can be performed, but the compensation accuracy is reduced due to coupling capacitance effects
Solution Approach 1:
The patent extracts the harmful coupling capacitance effect by introducing a separate detection line that is independent of the data transmission lines. This detection line is specifically dedicated to measuring the voltage change caused by the test signal, thereby separating the measurement function from the data transmission function and eliminating the coupling capacitance interference that affects compensation accuracy.
Solution Approach 2:
The patent introduces a detection line as an intermediary element between the test signal and the compensation calculation. This detection line serves as a mediator that accurately captures the voltage change without being directly coupled to the data transmission lines, thus preventing the coupling capacitance effect from compromising the measurement accuracy.
2Measurement precision
If data voltage is input to sub-pixels for compensation detection, then voltage change can be measured, but horizontal stripes appear due to inaccurate compensation
Solution Approach 1:
The patent segments the detection process by dividing the display panel into different rows and using alternating row selection. Specifically, it processes odd rows and even rows separately using alternating detection lines, which segments the compensation calculation into independent units. This segmentation prevents the propagation of errors across the entire display, thereby eliminating horizontal stripe artifacts.
Solution Approach 2:
The patent inverts the conventional approach by using zero grayscale as the test signal instead of non-zero grayscale. This inversion allows the detection line to measure the voltage change caused by the test signal without the interference of coupling capacitance from data transmission lines, thereby achieving accurate compensation and eliminating horizontal stripes.
3Measurement precision
If detection lines are charged with non-zero grayscale voltage, then sub-pixel voltage change can be detected, but coupling capacitance from data lines interferes with the measurement
Solution Approach 1:
The patent extracts the measurement function from the data transmission system by introducing a dedicated detection line that is physically separate from the data lines. This detection line is charged with the test signal independently, allowing accurate measurement of sub-pixel voltage changes without the coupling capacitance interference that would occur if the same line were used for both data transmission and measurement.
Solution Approach 2:
The detection line serves as an intermediary that bridges the test signal and the compensation calculation without being directly coupled to the data transmission lines. This intermediary role allows the detection line to accurately capture voltage changes while preventing coupling capacitance interference from the data lines from affecting the measurement.
Data Source
AI summary
The embodiments of the present application relate to a pixel compensation method, a pixel compensation apparatus and a display apparatus. In blanking periods of two adjacent display frames, detection lines for various color sub-pixels to be compensated in a (2n−1)th row and a (2n)th row are charged respectively, wherein a non-zero grayscale is input to one of the (2n−1)th row and the (2n)th row and a zero grayscale is input to the other one. Voltages on the detection lines for the various color sub-pixels to be compensated in the rows to which the non-zero grayscale and the zero grayscale are input are detected respectively, and a detected voltage of each color sub-pixel to be compensated in the row to which the non-zero grayscale is input is obtained according to voltages on detection lines for color sub-pixels in the (2n−1)th row and the (2n)th row and belonging to the same column.