LED Display Pixel Luminance Degradation Compensation
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Solution Overview
Problem
Electronic device displays, particularly those with light-emitting diodes, experience luminance degradation and color shifts over time due to aging effects, affecting display performance and image accuracy.
Innovation Solution
A pixel luminance degradation compensator is implemented in electronic devices to store aging history information for each pixel, computing compensation factors based on luminance and temperature data to adjust pixel luminance values, ensuring stable and accurate image display by offsetting reduced light output from aged pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If light-emitting diodes are used in display pixels, then energy efficiency and lifespan are improved, but luminance degradation occurs over time due to aging effects
Solution Approach 1:
The system performs preliminary characterization of each display during manufacturing to determine aging parameters before the display is shipped. This advance preparation allows the compensation algorithm to be pre-configured with the specific aging characteristics of each display, enabling accurate compensation to be applied from the first moment of use without requiring real-time measurement or adjustment.
Solution Approach 2:
The system implements a feedback mechanism where the measured luminance output of each pixel is continuously monitored and compared against expected values based on the stored aging parameters. Compensation factors are calculated and applied to adjust the drive signals, creating a closed-loop system that automatically corrects for aging-induced luminance degradation throughout the display's operational life.
2Productivity
If pixels are heavily used to display content, then display functionality is maintained, but luminance degradation accelerates due to aging
Solution Approach 1:
The system pre-determines the aging parameters for each pixel through characterization during manufacturing, establishing a baseline that accounts for how each pixel will degrade under various usage conditions. This preliminary data allows the system to predict and compensate for accelerated degradation even during heavy usage periods.
Solution Approach 2:
The system dynamically adjusts the compensation parameters based on the relationship between usage intensity and aging rate. By modifying the compensation factors in response to actual usage patterns, the system can maintain accurate luminance output even when pixels are heavily utilized, effectively decoupling productivity from degradation.
3Adaptability or versatility
If different colors are used in display pixels, then color display capability is improved, but color shifts occur over time due to differential aging
Solution Approach 1:
The system performs separate characterization measurements for each color channel (red, green, blue) during manufacturing, determining distinct aging parameters for each. This preliminary color-specific data allows the system to track and compensate for the differential aging of each color channel independently, preventing color shifts over time while maintaining full color display capability.
4Measurement precision
If compensation factors are applied to each pixel individually, then display accuracy is improved, but computational complexity increases
Solution Approach 1:
The system performs the complex computational work of determining compensation factors during the manufacturing process, when the display is stationary and can be characterized under controlled conditions. By pre-calculating and storing these factors in memory, the system avoids the need for complex real-time computations during normal operation, reducing the computational burden on the display driver while maintaining high accuracy.
Data Source
AI summary
An electronic device may be provided with a display. A content generator may generate frames of image data to be displayed on the display. The display may have an array of pixels that emit light to display images. The pixels may contain light-emitting devices such as organic light-emitting diodes, quantum dot light-emitting diodes, and light-emitting diodes formed from discrete semiconductor dies. As a result of aging, the light producing capabilities of the light-emitting devices may degrade over time. The electronic device may have a temperature sensor that gathers temperature measurements. A pixel luminance degradation compensator may apply compensation factors to uncorrected pixel luminance values associated with the frames of image data to produce corresponding corrected pixel luminance values for the display. The compensation factors may be based on aging history information such as pixel luminance history and temperature measurements.