Display Data Driver Gamma Interpolation for Target Luminance
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Solution Overview
Problem
Existing display devices struggle to accurately achieve a target luminance level due to non-linear relationships between data signal voltage levels and pixel emission characteristics, leading to discrepancies between intended and actual luminance.
Innovation Solution
The display device incorporates a controller and data driver that utilize look-up tables and linear interpolation to calculate offset values, adjusting gamma voltages and digital input values based on target luminance levels, ensuring accurate luminance through non-linear gamma correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gamma voltages are generated based on fixed sample luminance levels, then the device complexity is reduced, but the measurement precision of target luminance level is insufficient
Solution Approach 1:
The system pre-calculates and stores gamma voltage information for multiple sample luminance levels in a look-up table during the design phase. This preliminary action allows the controller to quickly retrieve and interpolate values without performing complex real-time calculations, thereby improving measurement precision while maintaining simple device operation.
Solution Approach 2:
The patent introduces an offset value as an intermediary parameter that compensates for the difference between interpolated gamma voltages and actual required gamma voltages. This offset mechanism mediates between the simplified look-up table approach and the precise target luminance requirement, enabling accurate luminance control without increasing device complexity.
2Manufacturing precision
If linear interpolation is used to calculate gamma voltages between sample luminance levels, then the calculation speed is improved, but the manufacturing precision of target luminance is insufficient
Solution Approach 1:
The system dynamically adjusts the offset value based on the target luminance level to compensate for the non-linear relationship between gamma voltages and luminance output. By changing the offset parameter according to different operating conditions, the system maintains high manufacturing precision without sacrificing calculation speed, as the offset adjustment is a simple arithmetic operation.
3Measurement precision
If gamma voltage information for all luminance levels is pre-stored, then the measurement precision is improved, but the loss of information due to memory constraints is reduced
Solution Approach 1:
Instead of storing gamma voltage information for all possible luminance levels, the patent segments the luminance range into discrete sample levels and stores data only at these segments. This segmentation reduces memory requirements significantly while maintaining adequate precision through interpolation between segments, effectively managing the trade-off between precision and storage capacity.
Solution Approach 2:
The system stores gamma voltage information for only a partial set of luminance levels (sample levels) rather than all possible levels. This partial action is sufficient to achieve the required measurement precision through interpolation, avoiding the excessive memory consumption that would result from storing complete luminance data for every possible level.
Data Source
AI summary
A display device including: a display panel; a scan driver; and a data driver, wherein the data driver includes: a controller configured to generate a gamma voltage control signal with respect to gamma voltage information corresponding to a target luminance level of an image displayed by the display panel; a gamma voltage generator configured to generate gamma voltages having a voltage range corresponding to the target luminance level based on the gamma voltage control signal; and a decoder configured to generate the data signal corresponding to a grayscale value using the gamma voltages, and wherein the controller calculates an offset value corresponding to the target luminance level and applies the offset value to values obtained using gamma voltage information about sample luminance levels to obtain gamma voltage information corresponding to the target luminance level.