OLED Luminance Deviation Compensation via Gamma Scaling
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Solution Overview
Problem
OLED displays experience luminance deviation and image distortion due to pixel degradation, as they cannot increase luminance beyond a predetermined maximum value, leading to uneven light emission and distortion.
Innovation Solution
A signal processor and OLED display system that calculates luminance deterioration values, generates compensation coefficients, and adjusts a compensation margin to create compensation image data, which is used to adjust input image data, thereby reducing luminance deviation and preventing image distortion by scaling gamma curves based on pixel deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pixel luminance is increased to compensate for degradation, then luminance uniformity is improved, but maximum luminance value cannot be exceeded causing image distortion
Solution Approach 1:
The system performs preliminary compensation by calculating deterioration values and generating compensation coefficients before displaying the image. The compensation image data is prepared in advance by adjusting pixel values based on predicted luminance degradation, allowing the display to maintain uniformity without exceeding maximum luminance limits during actual operation.
Solution Approach 2:
The system changes parameters by adjusting the gamma curve based on calculated compensation coefficients. The gamma correction parameters are dynamically modified to compensate for pixel degradation, transforming the luminance output characteristics to maintain uniformity while operating within the maximum luminance constraint.
2Stability of the object's composition
If compensation coefficients are calculated for each pixel, then luminance deviation is reduced, but processing complexity increases
Solution Approach 1:
The system segments the compensation process by calculating deterioration values and compensation coefficients for each pixel independently. This allows precise luminance deviation correction for individual pixels while maintaining overall system manageability through modular processing of pixel data.
Solution Approach 2:
The system introduces compensation image data as an intermediary between the original image data and the final display output. This intermediate representation allows complex per-pixel compensation to be performed once during data preparation, simplifying the actual display process while maintaining luminance uniformity.
3Manufacturing precision
If gamma curve is scaled with compensation coefficients, then image distortion is prevented, but calculation time increases
Solution Approach 1:
The gamma curve scaling with compensation coefficients is performed as a preliminary operation during image data preparation rather than in real-time during display. This advance calculation prevents image distortion while minimizing impact on display performance by completing the computationally intensive scaling before the image is rendered.
Solution Approach 2:
The system performs gamma curve scaling for all pixels using compensation coefficients, even though some pixels may not require full compensation. This excessive action ensures comprehensive distortion prevention across the entire image, accepting the computational cost as a trade-off for maintaining precise image fidelity.
Data Source
AI summary
A signal processor and an OLED display including the same are disclosed. In one aspect, the display includes a plurality of pixels and a luminance deterioration calculator configured to receive input image data and calculate luminance deterioration values of the pixels. A data compensator is configured to calculate compensation coefficients for each of the pixels based at least in part on the luminance deterioration values, adjust a compensation margin based at least in part on the maximum value of the compensation coefficients, and generate compensation image data for each of the pixels based at least in part on the compensation coefficients and the compensation margin. A panel driver is configured to generate data signals based at least in part on the compensation image data and transmit the data signal to the pixels and a timing controller configured to control the panel driver.