Timing Controller Sensing and Compensation for OLED Luminance
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Solution Overview
Problem
Organic light-emitting display devices face image quality degradation due to variations in threshold voltage and electron mobility, leading to uneven luminance and afterimages, especially when displaying high-luminance still images, which can shorten the lifespan of organic light-emitting diodes.
Innovation Solution
A timing controller and driving method that senses characteristics based on threshold voltage and electron mobility, using a data driver to output sensing, compensation, and data voltages in specific sections to correct and stabilize the drive current, thereby preventing image quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a drive current is supplied to organic light emitting diodes for long-time display, then the display can maintain continuous operation, but deterioration occurs and afterimages appear which shortens the lifespan
Solution Approach 1:
The patent applies preliminary action by performing sensing and compensation operations before the actual data signal is applied to the organic light emitting diodes. The sensing voltage is output first to measure transistor characteristics (threshold voltage and electron mobility), then compensation values are calculated and stored in advance, so that when the data signal is applied, the transistors are already in an optimized state that prevents deterioration and afterimage formation during continuous operation
2Illumination intensity
If high luminance still images are displayed, then the display can provide bright and clear images, but deterioration occurs more likely which shortens the lifespan of organic light emitting diodes
Solution Approach 1:
The patent implements feedback by continuously sensing the actual characteristics of the transistors through sensing voltages and using this information to adjust compensation values. The sensing unit measures threshold voltage and electron mobility, the controller calculates appropriate compensation values based on these measurements, and stores them for subsequent data signal application. This closed-loop feedback mechanism ensures that even during high-luminance still image display, the transistors operate within optimal parameters that prevent excessive deterioration and extend LED lifespan
3Ease of manufacture
If process deviation occurs in driving transistors, then manufacturing can be completed with standard processes, but threshold voltage differences occur between transistors which causes drive current deviation and luminance unevenness
Solution Approach 1:
The patent applies local quality by providing individualized compensation for each transistor based on its specific characteristics. Instead of using a uniform compensation value for all transistors, the sensing unit measures the threshold voltage and electron mobility of each transistor separately, and the controller stores specific compensation values for each transistor in the pixel circuit. This localized approach ensures that each transistor operates at its optimal performance level, eliminating luminance unevenness while maintaining ease of manufacture with standard fabrication processes
Data Source
AI summary
An organic light-emitting display device includes: a display panel in which a plurality of data lines and a plurality of gate lines are arranged to overlap each other and that includes a plurality of subpixels which are arranged in areas in which the plurality of data lines and the plurality of gate lines overlap each other; a data driver that supplies a data signal to the plurality of data lines; a gate driver that supplies a gate signal to the plurality of gate lines; and a timing controller that controls the data driver and the gate driver such that the data driver outputs a sensing voltage in a first section, outputs a compensation voltage in a second section, and outputs a data voltage in a third section.