Display Device Gamma Voltage Correction via Lookup Tables
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Solution Overview
Problem
Display devices experience brightness errors due to limited hardware capabilities, which result in decreased maximum brightness and increased load on gamma voltages, especially in low grayscale sections, leading to inaccuracies in image representation.
Innovation Solution
A display device configuration that includes a power supply for first and second supply voltages, a brightness compensator for data correction, an interpolator using a gamma lookup table to generate gamma voltages, and a data driver that selects gamma voltages based on output data values, with additional dimming lookup tables for further correction, ensuring a linear relationship between gamma voltages and output data values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gamma voltages are linearly interpolated between reference gamma voltages due to limited hardware, then device complexity is reduced, but brightness error increases
Solution Approach 1:
The patent pre-calculates and stores correction values in lookup tables during the design phase. These correction values compensate for the linear interpolation error, allowing the system to maintain high brightness accuracy without increasing hardware complexity during operation.
Solution Approach 2:
The patent creates a digital copy of the ideal gamma curve characteristics through lookup tables. Instead of physically implementing a complex gamma voltage generator, the system uses a simplified linear interpolator combined with pre-stored correction data that replicates the desired non-linear gamma response.
2Use of energy by moving object
If dimming driving scheme is used to reduce maximum brightness, then power consumption is reduced, but load concentration on specific gamma voltages increases brightness error
Solution Approach 1:
The patent applies different correction strategies to different brightness ranges. Separate lookup tables are used for different grayscale sections, with specific correction values tailored to the load concentration characteristics of each section, particularly addressing the low grayscale section where load concentration occurs during dimming.
Solution Approach 2:
The patent changes the correction parameters based on the operating conditions. Different correction values are applied depending on the grayscale level and dimming state, allowing optimal compensation for brightness error across the entire brightness range while maintaining reduced power consumption.
3Measurement precision
If more reference gamma voltages are generated to reduce brightness error, then brightness accuracy is improved, but device complexity and hardware resources increase
Solution Approach 1:
The patent uses lookup tables to store pre-calculated correction data that replicates the effect of having multiple reference gamma voltages. This digital copying approach achieves high brightness accuracy without requiring additional hardware resources for generating and storing multiple reference voltages.
Solution Approach 2:
The patent replaces expensive, resource-intensive hardware (multiple reference gamma voltage generators) with a cheaper computational approach using lookup tables and interpolation. The lookup tables act as disposable pre-computed data structures that provide high accuracy without ongoing hardware resource consumption.
Data Source
AI summary
A display device may include a display panel including a plurality of pixels. An interpolator may be configured to generate a first voltage value corresponding to an input data value using a preset gamma lookup table. A gamma compensator may be configured to, based on a dimming value, select at least one of a plurality of preset dimming lookup tables, and may calculate a first output data value by correcting the first voltage value based on the at least one dimming lookup table. A gamma voltage generator may be configured to generate a plurality of gamma voltages having a linear relationship. A data driver may be configured to select a first gamma voltage from among the gamma voltages based on the first output data value, and provide the first gamma voltage, as a data voltage, to the display panel.