OLED Display Luminance Uniformity Compensation via Sensing
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Solution Overview
Problem
Conventional organic light emitting displays face challenges in maintaining uniform luminance due to the deterioration of organic light emitting diodes and variations in threshold voltage and mobility of drive transistors over time, leading to reduced light emission and non-uniform image display.
Innovation Solution
An organic light emitting display system that includes a sensing unit to monitor the deterioration of organic light emitting diodes and threshold voltage/mobility of drive transistors, a control block to store and process this information, and a timing controller to generate adjusted data signals to compensate for these changes, ensuring consistent luminance across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional organic light emitting displays are used without compensation mechanisms, then the device structure remains simple, but the luminance uniformity deteriorates over time due to OLED degradation and transistor parameter variations
Solution Approach 1:
The patent measures OLED characteristics and transistor parameters (threshold voltage, mobility) in advance during a sensing period before normal display operation. These measured values are stored and used to generate compensation data that adjusts the driving signals, thereby preventing luminance non-uniformity before it occurs during normal operation.
Solution Approach 2:
The patent implements a feedback mechanism where the measured OLED and transistor parameters are used to generate compensation data that adjusts the driving signals. The sensing unit continuously monitors device characteristics, and the timing controller uses this feedback information to modify the data signals, ensuring luminance uniformity is maintained despite device degradation or parameter variations.
2Reliability
If sensing and compensation mechanisms are added to maintain luminance uniformity, then luminance uniformity is maintained over time, but the device complexity increases due to additional sensing units, control blocks, and timing controller functions
Solution Approach 1:
The patent combines the sensing unit, control block, and timing controller into an integrated display system. The sensing unit is coupled to the power lines and shares circuit resources with the display operation. The control block and timing controller process the sensed information and generate compensation data that is fed back to the data driver, merging multiple functions into a unified system architecture.
Solution Approach 2:
The power lines serve dual purposes: they supply power to the OLED during normal operation and serve as sensing paths to measure OLED characteristics and transistor parameters during the sensing period. This multi-functional use of existing circuit elements reduces the need for completely separate sensing circuitry, thereby limiting the increase in device complexity.
3Manufacturing precision
If additional control signals and sensing operations are implemented, then compensation for OLED deterioration and transistor variations is achieved, but the operating cycle becomes more complex with multiple timing phases
Solution Approach 1:
The patent implements a periodic sensing operation that occurs at specific intervals (e.g., at the beginning of each frame or at predetermined timing) to measure OLED and transistor parameters. During the sensing period, the display operation is temporarily suspended, and compensation data is generated. During the normal display period, the pre-computed compensation data is applied without requiring continuous sensing, thereby reducing real-time operating complexity while maintaining precision.
Solution Approach 2:
The compensation data is generated in advance during the sensing period before the normal display operation begins. The timing controller uses the measured parameters to pre-calculate the adjusted data signals, which are then stored and applied during the display period. This preliminary computation eliminates the need for complex real-time calculations during active display, simplifying the operating cycle.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively maintains uniform luminance by compensating for organic light emitting diode deterioration and transistor mobility variations, thereby ensuring consistent image display quality over time.
Implementation Method 1
the organic light emitting diode generating the light by means of the recombination of electrons and holes
Data Source
AI summary
An organic light emitting display capable of displaying an image with uniform luminance regardless of deterioration of an organic light emitting diode and threshold voltage and/or mobility of a drive transistor is disclosed. The organic light emitting display senses deterioration of the organic light emitting diode and threshold voltage and/or mobility of a drive transistor and modifies the data supplied to the pixel according to the sensed parameters.