Display Device Bilinear Compensation Lookup Table Memory Optimization
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Solution Overview
Problem
The increasing size of display devices leads to luminance differences across the panel due to manufacturing process limitations, causing mura (image irregularities) which are difficult to prevent without significant memory usage for storing compensation values for all pixels.
Innovation Solution
Storing compensation values for specific locations in a lookup table and using a bilinear interpolation method to calculate values for other locations, implemented in an ASIC with adders, multipliers, and bit shifters to avoid division operators, reducing hardware capacity and improving operating speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compensation values for all pixels are stored in the lookup table, then mura prevention is improved, but memory usage increases significantly
Solution Approach 1:
The patent divides the display panel into multiple regions and stores compensation values only for specific locations (e.g., one value per region) rather than all pixels. The bilinear interpolation method then calculates compensation values for remaining pixels based on these stored values, significantly reducing memory requirements while maintaining effective mura prevention across the entire panel.
Solution Approach 2:
The patent uses bilinear interpolation to calculate and generate compensation values for pixels whose values are not directly stored in the lookup table. This mathematical copying approach derives accurate compensation values from nearby stored values, eliminating the need to store every individual pixel's compensation value while maintaining precision.
2Measurement precision
If a divider is used in the bilinear interpolation calculation, then calculation accuracy is improved, but hardware capacity and operating speed deteriorate
Solution Approach 1:
The patent replaces the division operator with multiplication and bit shift operations in the bilinear interpolation calculation. Specifically, the formula uses multiplication by pre-calculated coefficients (K1, K2, K3) followed by bit shifting to achieve the same mathematical result as division would provide, but with significantly reduced hardware complexity and improved operating speed.
Solution Approach 2:
The patent transforms the calculation parameters by pre-calculating coefficients (K1, K2, K3) that encode the division results. These coefficients are stored in the lookup table or calculated once, allowing runtime calculations to use only multiplication and bit shift operations, thereby changing the computational parameters from division-based to multiplication-based for optimal hardware performance.
Data Source
AI summary
A display device is disclosed. The display device includes: a plurality of pixels; a memory storing a lookup table including compensation values for pixels at specific locations of the display. The lookup table also stores compensation values obtained by a bilinear compensation method. The display also includes a data compensator calculating the compensation values corresponding to a location where an image signal is displayed using the compensation values and substitution values stored in the lookup table. The substitution values are obtained by bit-shifting the compensation values acquired by bilinear compensation method. The display device avoids the need to use large and slow divider circuits used in ICs implementing bilinear compensation method.