Pixel Uniformity Compensation Using Gain and Offset Correction
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Solution Overview
Problem
Electronic display devices, such as OLEDs and micro-LEDs, face non-uniformity issues in gray level output due to manufacturing variations and ambient conditions, leading to visual artifacts like color mixing and frame mura, as different pixels emit different colors or luminance levels even with the same electrical input.
Innovation Solution
A compensation system that uses gain and offset correction factors, determined through optical and electrical testing, as well as real-time sensing, to adjust the voltages and currents provided to each pixel, generating a correction spatial map, brightness adaptation lookup table, and gray conversion lookup table to ensure uniformity across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manufacturing processes are simplified to reduce cost and increase productivity, then productivity improves, but pixel uniformity deteriorates due to manufacturing variations
Solution Approach 1:
The patent applies preliminary action by performing gain and offset correction during the manufacturing process. Correction factors are calculated and stored in lookup tables before the display device is shipped, allowing uniformity compensation to be built into the device during production rather than requiring post-manufacturing adjustments. This maintains productivity while improving pixel uniformity through pre-computed correction data.
Solution Approach 2:
The patent changes electrical parameters (voltage and current) provided to individual pixels based on correction factors. By adjusting these electrical parameters pixel-by-pixel using lookup tables containing gain and offset values, the system compensates for manufacturing variations without requiring rework or additional manufacturing steps, thus maintaining productivity while achieving uniformity.
2Manufacturing precision
If complex compensation algorithms are implemented to improve pixel uniformity, then pixel uniformity improves, but device complexity increases
Solution Approach 1:
Complex correction calculations are performed in advance during manufacturing and stored in lookup tables. During operation, the display device simply retrieves pre-computed correction factors from these tables and applies them to pixel data, avoiding the need for complex real-time calculations. This reduces operational complexity while maintaining uniformity correction capability.
Solution Approach 2:
The patent replaces complex real-time computational systems with simpler lookup table-based retrieval and application. Instead of implementing complex algorithms that run continuously during device operation, the system uses pre-computed data stored in memory, substituting mechanical/computational complexity with simpler data retrieval and application operations.
3Manufacturing precision
If real-time sensing and adaptive correction are implemented to improve uniformity under varying ambient conditions, then pixel uniformity improves, but use of energy increases
Solution Approach 1:
Correction factors for different ambient conditions are pre-computed and stored in lookup tables during manufacturing. When ambient conditions change, the system retrieves appropriate correction factors from these tables rather than performing energy-intensive real-time sensing and calculation. This reduces energy consumption while maintaining the ability to compensate for ambient variations.
Solution Approach 2:
The system applies correction factors from lookup tables that were pre-computed with excessive detail and precision. Rather than performing minimal real-time adjustments, the system uses pre-computed correction data that covers a range of ambient conditions, allowing selective application without continuous sensing or calculation, thus reducing energy use while maintaining uniformity.
Data Source
AI summary
A display device may include a processor that may receive image data, such that the image data may include gray level data and display brightness value (DBV) data for a first pixel of a display. The processor may then determine a gain compensation factor associated with the first pixel based on a correction spatial map, a brightness adaptation lookup table (LUT), the gray level data, and the DBV data. The processor may then determine an offset compensation factor associated with the first pixel based on the correction spatial map, the brightness adaptation lookup table (LUT), the gray level data, and the DBV data. The processor may generate compensated gray level data by applying the gain compensation factor and the offset compensation factor to the gray level data and transmit the compensated gray level data to pixel driving circuitry associated with the first pixel.