OLED Pixel Compensation for Long Range Uniformity
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Solution Overview
Problem
Organic light emitting displays face challenges in maintaining Long Range Uniformity (LRU) due to deviations in luminance, chromaticity coordinates, and color temperature across pixels, leading to inconsistent image output even when the same image is input, which reduces display reliability and lifespan.
Innovation Solution
An organic light emitting display system that measures luminance, chromaticity coordinates, and color temperature after panel fabrication, stores compensation values in a look-up table, and adjusts power supply voltage, data voltage, and light emission time to ensure consistent image output across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material and process improvements are made to reduce resistance and increase electron-hole mobility, then device performance is improved, but Long Range Uniformity (LRU) of video characteristics remains degraded due to pixel-to-pixel deviations
Solution Approach 1:
The patent measures luminance, chromaticity coordinates, and color temperature of each pixel after OLED fabrication but before final assembly, storing these values in a look-up table. This preliminary measurement and storage of compensation data allows subsequent correction of pixel-to-pixel variations without requiring re-fabrication or material changes.
Solution Approach 2:
The patent adjusts drive conditions (voltage, current, emission time) based on stored compensation values to correct pixel-to-pixel deviations. By dynamically changing operational parameters rather than physical properties, the system achieves uniform video output across all pixels despite manufacturing variations.
2Manufacturing precision
If compensation values are stored in memory for each pixel, then Long Range Uniformity is improved, but device complexity increases due to additional memory and compensation circuitry
Solution Approach 1:
Instead of modifying the physical OLED structure or adding complex real-time adjustment circuitry, the patent creates a digital copy of each pixel's characteristics in a look-up table stored in memory. This virtual model allows compensation calculations to be performed on copied data rather than requiring complex hardware modifications to the actual display.
Solution Approach 2:
The patent introduces a compensation value table as an intermediary between the OLED pixels and the drive circuitry. This intermediate layer of compensation data mediates the relationship between manufacturing variations and drive signals, simplifying the overall system architecture by decoupling pixel characteristics from drive requirements.
3Manufacturing precision
If voltage and emission time compensation is applied to each pixel, then identical images are displayed across pixels, but manufacturing cost increases due to additional measurement and compensation processes
Solution Approach 1:
The patent performs luminance, chromaticity, and color temperature measurements during or after OLED fabrication but before final product assembly. By completing compensation data collection early in the manufacturing process, the patent avoids requiring additional measurement steps later and enables compensation values to be integrated into the standard manufacturing flow.
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
Improves both Long Range Uniformity (LRU) and Short Range Uniformity (SRU) by compensating voltage and emission time, ensuring identical images are displayed across pixels, thereby enhancing display reliability and extending lifespan.
Implementation Method 1
An organic light emitting diode may be composed of an anode, an organic layer and a cathode. The organic layer may be composed of an emitting layer (EML) that emits light by forming an exciton when an electron and a hole contact each other
Data Source
AI summary
An organic light emitting display and an image compensation method improves the Long Range Uniformity (LRU) of the output image by displaying the identical image when the identical image is input to each pixel, by measuring the luminance, chromaticity coordinates and color temperature after an organic light emitting display panel is fabricated, by storing the compensation values thereof in a memory in the form of a look-up table in advance, and by compensating one of a power supply voltage, a data voltage and a light emission time. The organic light emitting display device and an image compensation method includes: a video signal processor; a control unit coupled to the video signal processor to compensate the luminance, chromaticity coordinates and color temperature in order to have the identical output image in relation to the identical input image; and an organic light emitting display panel coupled to the control unit to display the compensation image in which the luminance, chromaticity coordinates and color temperature have been compensated.