Data Driver Output Compensation Using Multi-Voltage Lookup Tables
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Solution Overview
Problem
Display devices experience variations in electrical characteristics among pixels due to process variations, leading to inaccurate compensation of output deviations in data drivers, which can result in visible vertical lines on the display panel.
Innovation Solution
A method involving a sensing circuit to measure first and second output values, generate a compensation look-up table based on these values, and apply compensation values to the data driver's output voltages to correct deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If output amplifiers are used to provide data voltages to data lines, then the display device can drive pixels with different electrical characteristics, but output deviations occur among different output amplifiers depending on input voltage, leading to inaccurate compensation
Solution Approach 1:
The patent applies parameter changes by measuring output deviations at multiple different input voltage levels (first voltage, second voltage, third voltage) and generating separate compensation values for each voltage level. This resolves the contradiction by adapting the compensation parameters to match the varying operating conditions of the output amplifiers, ensuring accurate compensation across different input voltages while maintaining the ability to drive pixels with different electrical characteristics.
2Device complexity
If compensation is performed using a single voltage level, then the compensation process is simple, but output deviations vary with input voltage causing inaccurate compensation
Solution Approach 1:
The patent implements dynamics by transitioning from a static single-voltage compensation approach to a dynamic multi-voltage compensation approach. The compensation look-up table is generated with multiple entry points corresponding to different input voltage levels, allowing the system to dynamically select the appropriate compensation values based on the actual input voltage to the output amplifiers. This resolves the contradiction by making the compensation process adaptive to varying operating conditions while maintaining manageable complexity through systematic measurement and table generation.
3Measurement precision
If multiple measurement points are used to generate compensation values, then output deviations are accurately compensated, but the measurement and processing time increases
Solution Approach 1:
The patent applies preliminary action by performing the time-consuming multi-voltage measurements and compensation value calculations in advance during the compensation look-up table generation phase. The generated look-up table stores pre-calculated compensation values for multiple voltage levels, which can then be quickly retrieved during normal operation. This resolves the contradiction by shifting the time investment to an offline setup phase, enabling fast real-time compensation while maintaining high accuracy through multiple measurement points.
Data Source
AI summary
A method of compensating for an output of a data driver of a display device includes measuring a first output value of a sensing circuit that senses pixels by applying an external voltage to the sensing circuit, measuring second output values of the sensing circuit by applying output voltages within an output range of the data driver to the sensing circuit through output amplifiers of the data driver, generating a compensation look-up table based on the first output value and the second output values, and compensating for the output voltages of the data driver based on the compensation look-up table.