OLED Pixel Circuit Hysteresis Measurement and Compensation
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Solution Overview
Problem
Existing organic light-emitting display devices face challenges in accurately measuring hysteresis characteristics in real-time, which affects their performance and image quality.
Innovation Solution
The implementation of a specific configuration in the organic light-emitting display device that includes a sensing transistor, a scan transistor, and a data driver, allowing for real-time hysteresis measurement by providing distinct data signals during different periods within a frame, enabling the measurement of driving current and generating compensation data to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hysteresis measurement is performed using existing methods, then measurement can be conducted, but measurement precision is insufficient and residual images occur
Solution Approach 1:
The patent divides the frame period into multiple distinct periods (first period for measurement data input, second period for grayscale data input, third period for sensing transistor operation) to separately handle measurement and display functions. This temporal segmentation allows accurate hysteresis measurement without interfering with normal display operations, thereby improving measurement precision while preventing residual images.
Solution Approach 2:
The patent implements a feedback mechanism where the sensing transistor measures the driving current during the third period, and this measurement information is used to generate compensation data. The compensation data is then fed back to correct hysteresis effects in subsequent frames, improving measurement precision and eliminating residual images through continuous correction.
2Measurement precision
If real-time hysteresis measurement is implemented during image display, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The sensing transistor serves multiple functions: it acts as a switch during the first and second periods, and as a measurement device during the third period. The scan transistor similarly performs switching in the first and second periods and is controlled during the third period. This multi-functionality allows real-time hysteresis measurement without adding excessive circuit complexity.
Solution Approach 2:
The patent employs periodic action by operating the sensing transistor during a specific third period within each frame, rather than continuously. The scan transistor is turned on during the first and second periods and controlled during the third period. This periodic operation enables real-time measurement capability while managing device complexity through time-multiplexed control.
3Ease of operation
If scan transistor is turned on during first and second periods, then data signals can be input, but measurement operation is interfered during third period
Solution Approach 1:
The scan transistor is turned on during the first and second periods to allow data signal input, and then turned off during the third period to enable accurate hysteresis measurement by the sensing transistor. This periodic switching ensures that measurement operations during the third period are not interfered with by scan operations, thereby maintaining measurement precision while preserving data input capability.
Data Source
AI summary
An organic light-emitting display device may include a first pixel, a first data line, a first scan line, a data driver, and a scan driver. The first pixel unit may include a sensing transistor and a scan transistor. The data driver may be electrically connected to the scan transistor through the first data line. The scan driver may be electrically connected to the scan transistor through the first scan line. The scan transistor may be turned on during a first period and a second period. The sensing transistor may be turned on during a third period between the first period and the second period. The first period, the second period, and the third period are included in one frame.