Gamma Correction for Low Grayscale Values Using Driving Current
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Solution Overview
Problem
Existing gamma correction methods for display devices face challenges in accurately correcting image quality for low grayscale values due to performance limitations of light receiving elements, leading to increased measurement time and decreased accuracy.
Innovation Solution
A gamma correction method that measures the driving current for low grayscale values, uses a driving current-luminance calibration function to predict luminance, compares it to a target luminance, and adjusts the grayscale voltage with an offset value to achieve the target luminance, thereby correcting the image quality without directly measuring luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If luminance measurement is performed for low grayscale values, then gamma correction accuracy can be improved, but measurement time increases significantly and accuracy decreases due to performance limitations of light receiving elements
Solution Approach 1:
The patent introduces driving current as an intermediary measurement parameter instead of directly measuring luminance. The driving current measured by the source driver is used to calculate predicted luminance through a calibration function, serving as a mediator that avoids the performance limitations of light receiving elements while still enabling gamma correction accuracy
Solution Approach 2:
The patent replaces the optical measurement system (luminance sensor/meter with light receiving elements) with an electrical measurement system (current measurement). By measuring driving current electrically and converting it to predicted luminance through calibration, the system avoids the speed and accuracy limitations of optical detection for low grayscale values
2Manufacturing precision
If luminance measurement is performed for low grayscale values, then gamma correction can be achieved, but measurement accuracy decreases due to performance limitations of light receiving elements
Solution Approach 1:
The patent uses driving current as an intermediary that can be measured with high precision by the source driver's existing current measurement capabilities. This electrical measurement intermediary bypasses the accuracy limitations of light receiving elements when measuring low luminance values, enabling precise gamma correction for low grayscale values
Solution Approach 2:
The patent changes the measurement parameter from luminance (optical property) to driving current (electrical property). This parameter transformation allows utilization of the source driver's high-precision current measurement capabilities, which are not limited by the performance constraints that affect light receiving elements at low luminance levels
Data Source
AI summary
The gamma correction method for a display device measures a first driving current according to a first grayscale voltage corresponding to the low grayscale value, determines a predicted luminance based on a driving current-luminance calibration function and the first driving current, compares the predicted luminance and a first target luminance for the low grayscale value, determines a first offset value based on the first driving current and the first target luminance when the predicted luminance is different from the first target luminance, and corrects the first grayscale voltage based on the first offset value. That is, the gamma correction method may measure the driving current to perform gamma correction for the low grayscale value, and shorten a process time of the gamma correction compared to performing the gamma correction for the low grayscale value by measuring luminance.