Display Voltage Compensation for Low Grayscale Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display technologies face challenges in accurately compensating low grayscale value areas of images, leading to greenish displays and inaccurate luminance measurements, which complicates the compensation process and reduces productivity due to increased measurement time.
Innovation Solution
A display apparatus comprising a display panel, a voltage compensator, and a data driver that determines normal and low grayscale gamma voltages based on measured luminances, with a color compensator applying corrections when color coordinates exceed target ranges, using a function y = ax + b to calculate variables and generate data voltages for improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed representative gamma voltage is used to compensate low grayscale value area, then the compensation process is simple, but the display image becomes greenish and the low grayscale value area is not compensated enough
Solution Approach 1:
The patent segments the grayscale compensation process into two distinct parts: (1) measuring and determining gamma voltages for normal grayscale values (greater than or equal to a reference voltage) using fixed representative gamma voltages, and (2) separately determining gamma voltages for low grayscale values (less than reference voltage) based on measured luminances and a grayscale-voltage curve. This segmentation allows each part to be optimized independently, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The patent applies different compensation strategies to different grayscale value ranges. For normal grayscale values, a simple fixed representative gamma voltage approach is used. For low grayscale values, a more sophisticated approach involving luminance measurement, grayscale-voltage curve determination, and variable calculation (a, b, c) is applied. This local differentiation ensures high accuracy where needed while maintaining overall process efficiency.
2Measurement precision
If measuring luminance of low grayscale value area by measuring apparatus is performed to increase accuracy, then measurement accuracy increases, but measuring time increases and compensation cannot be accurate due to reliability and takt time constraints
Solution Approach 1:
The patent performs preliminary measurements of luminances for multiple grayscale values (including both normal and low grayscale values) during the manufacturing process. These measurements are stored and used to determine the grayscale-voltage curve and calculate the variables (a, b, c) in advance. This preliminary action allows the low grayscale gamma voltages to be accurately determined without requiring time-consuming measurements during final compensation.
Solution Approach 2:
The patent creates a mathematical model (grayscale-voltage curve with variables a, b, c) that copies the relationship between luminance and voltage from measured data. This model can then be used to predict and determine low grayscale gamma voltages accurately without requiring direct measurement for each case, thus reducing measurement time while maintaining accuracy.
3Manufacturing precision
If low grayscale gamma voltage is determined based on measured luminances for multiple grayscale values, then display quality of low grayscale image is enhanced, but the process becomes more complex
Solution Approach 1:
The patent changes the parameters used for voltage determination based on grayscale value. For normal grayscale values, fixed representative gamma voltages are used. For low grayscale values, the system calculates variables (a, b, c) based on measured luminances and uses these to determine the low grayscale gamma voltage through the grayscale-voltage curve equation. This parameter adaptation resolves the contradiction by applying appropriate complexity only where needed.
Data Source
AI summary
A display apparatus includes a display panel, a voltage compensator, and a data driver. The display panel is configured to display an image. The voltage compensator is configured to compensate a plurality of normal grayscale gamma voltages corresponding to a plurality of grayscale values equal to or greater than a reference voltage based on a plurality of measured luminances for the plurality of the grayscale values, and to determine a low grayscale gamma voltage less than the reference voltage based on the measured luminances. The data driver is configured to generate a data voltage based on the normal grayscale gamma voltage and the low grayscale gamma voltage and to output the data voltage to the display panel.