Pixel Driving Method for OLED Brightness Compensation
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Solution Overview
Problem
Organic light emitting diode display panels face issues with image quality due to variations in electrical characteristics of current control switches and organic light emitting diodes, affecting brightness and overall image quality.
Innovation Solution
A pixel driving method that includes a plurality of scan lines, data lines, and pixels with specific transistor configurations, where a third transistor connects or disconnects second transistors between columns, allowing for voltage level reading and compensation to provide consistent data voltages to pixels, thereby compensating for differences in electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a current control switch is used to control current through the organic light emitting diode, then the brightness of the organic light emitting diode can be controlled, but the threshold voltage variations of the current control switch and voltage variations of the organic light emitting diode affect image quality
Solution Approach 1:
The patent applies preliminary action by reading the voltage levels of the second transistors before providing data voltages to the pixels. This allows the system to compensate for threshold voltage variations and OLED voltage variations in advance, ensuring consistent brightness and image quality across all pixels before the actual display operation begins.
Solution Approach 2:
The patent implements feedback by reading the voltage levels of the second transistors and using this information to adjust and provide corresponding data voltages to the pixels. This feedback mechanism compensates for electrical characteristic variations, ensuring that each pixel receives the appropriate voltage to achieve uniform brightness and maintain image quality.
2Reliability
If voltage levels of gate ends of second transistors are read to provide compensation, then electrical characteristic differences can be compensated, but additional reading and compensation operations increase processing time
Solution Approach 1:
The patent performs the voltage level reading and compensation calculation as a preliminary action before the main display operation. By completing the compensation process in advance, the system eliminates the need for continuous real-time adjustments during display, thereby minimizing the time loss while ensuring electrical characteristic consistency.
3Reliability
If third transistors are used to connect or disconnect second transistors between columns, then compensation can be implemented, but the transistor configuration and control operations increase device complexity
Solution Approach 1:
The third transistors serve multiple functions: they connect or disconnect the second transistors between columns, enable the reading of voltage levels, and facilitate the compensation process. By making these transistors multi-functional, the patent reduces the need for additional dedicated components, thereby managing device complexity while maintaining compensation capability.
4Measurement precision
If data lines are coupled to current source for reading voltage levels, then accurate voltage measurement can be achieved, but switching between voltage source and current source increases operational complexity
Solution Approach 1:
The patent employs periodic action by sequentially switching the data lines between voltage source and current source modes. During the reading phase, the data lines are coupled to the current source for accurate voltage measurement, and during the display phase, they are coupled to the voltage source for normal operation. This periodic switching is controlled in a systematic manner to maintain ease of operation while achieving measurement precision.
Data Source
AI summary
A pixel driving method of a display panel is disclosed. The display panel includes a plurality of scan lines, data lines and pixels. Each of the pixel includes a first transistor with a first end coupled to the data line, and a gate end coupled to the scan line, a second transistor with a first end selectively coupled to a voltage source or current source, and a gate end coupled to a second end of the first transistor, and a light-emitting unit with a first end coupled to a second end of the second transistor. The method includes turning on the first transistors of the pixels; coupling the data lines and first ends of the second transistors to the current source; reading voltage levels of gate ends of the second transistors; and providing corresponding data voltages to the pixels according to voltage levels of gate ends of the second transistors.