Liquid Crystal Display Overdrive Control for Response Time
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Solution Overview
Problem
Liquid crystal displays face challenges in determining the overdrive voltage required to accelerate response time, leading to issues like ghosting, streaking, and motion blur due to slow response with respect to driving voltage.
Innovation Solution
A method involving a liquid crystal display with sub-pixels arranged in an array, using frame rate weights and overdrive lookup tables to generate an initial overdrive value, and an error correction mechanism to produce a corrected overdrive value for precise voltage application, thereby improving transition between gray levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If overdrive voltage is applied to accelerate response time, then speed of gray level transition is improved, but manufacturing precision of overdrive voltage determination deteriorates
Solution Approach 1:
The patent pre-calculates and stores overdrive voltage values in lookup tables (LUTs) for various frame rates and gray level transitions before operation. During display operation, the system only needs to query the appropriate LUT based on current frame rate and gray level values, rather than calculating overdrive voltages in real-time. This preliminary preparation resolves the contradiction by providing accurate overdrive voltage determination without adding computational complexity during operation.
Solution Approach 2:
The patent divides the frame rate range into multiple intervals and creates separate LUTs for each interval, with each LUT containing overdrive voltage values optimized for its specific frame rate range. When the frame rate changes, the system selects the appropriate LUT and potentially applies interpolation to determine the precise overdrive voltage. This parameter-based segmentation allows accurate overdrive voltage determination across varying frame rates while maintaining fast response times.
2Manufacturing precision
If frame rate weight and error correction are used to improve overdrive voltage accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the overdrive voltage determination process into distinct functional modules: frame rate detection module, LUT selection module, interpolation calculation module, and error correction module. Each module handles a specific aspect of the determination process, making the overall complex system manageable and maintainable. The segmentation allows each module to be optimized independently while working together to achieve high accuracy.
Solution Approach 2:
The patent introduces lookup tables as intermediary data structures between the frame rate detection and overdrive voltage output. The LUTs pre-store calculated overdrive voltage values, acting as a mediator that translates frame rate and gray level inputs into accurate overdrive voltage outputs without requiring complex real-time calculations. This intermediary approach simplifies the circuit complexity while maintaining high precision.
Data Source
AI summary
A liquid crystal display includes a plurality of sub-pixels arranged in an array. A method of driving the liquid crystal display includes determining a frame rate weight according to a current frame rate of a plurality of image frames, performing linear prediction according to the current frame rate to generate an initial overdrive value of a sub-pixel, selecting an error correction value according to a previous gray level of the sub-pixel, generating an overdrive weight according to the previous gray level and a current gray level of the sub-pixel, generating an overdrive offset according to a product of the error correction value, the frame rate weight and the overdrive weight, combining the initial overdrive value and the overdrive offset to generate a corrected overdrive value, and driving the sub-pixel according to the corrected overdrive value.