Liquid Crystal Display Black Data Insertion Polarity Control
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Solution Overview
Problem
Active matrix liquid crystal displays suffer from motion blur due to their hold drive characteristics, leading to blurry images compared to cathode ray tubes, which operate in an impulse drive manner, resulting in a perceived image that is not clear and blurry.
Innovation Solution
The liquid crystal display employs a black data insertion method with a POL conversion control signal that inverts polarity every two frame periods in black data insertion mode and every one frame period in normal drive mode, using a POL conversion circuit to prevent residual voltage accumulation and image sticking, while maintaining fast response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If black data is inserted between video data to achieve impulse drive effect, then motion blur is reduced, but luminance reduction and flicker occur
Solution Approach 1:
The patent implements periodic polarity inversion of the black data voltage inserted between video frames. By alternating the polarity of black data voltage every frame period, the system maintains the impulse drive effect for motion clarity while preventing residual voltage accumulation that would cause image sticking, thus resolving the contradiction between image clarity and luminance stability
2Reliability
If black data is inserted with polarity inversion every frame period, then DC image sticking is reduced, but residual voltage accumulates and image sticking occurs
Solution Approach 1:
The patent extends the polarity inversion cycle from every frame period to every other frame period for black data insertion. This continuous alternation of polarity over a longer period ensures that residual voltages are effectively cancelled out, preventing image sticking while maintaining the benefits of black data insertion for reducing motion blur
3Duration of action of stationary object
If liquid crystal display operates in hold drive manner, then data is held during field period, but motion blur occurs due to hold characteristics
Solution Approach 1:
The patent introduces periodic black data insertion between video frames to create an impulse drive effect. By periodically inserting black data at specific intervals (every other frame), the system momentarily resets the liquid crystal state, reducing the hold characteristics that cause motion blur while maintaining acceptable data holding capability for normal operation
Data Source
AI summary
The present invention relates to a liquid crystal display, wherein the liquid crystal display includes a POL conversion control signal generating unit for generating a POL conversion control signal that is inverted at predetermined time intervals in a black data insertion mode and is fixed at a specific logic level in a normal drive mode, a timing controller for outputting a first polarity control signal that is inverted every a predetermined period, a POL conversion circuit that receives the POL conversion control signal and the first polarity control signal to output a second polarity control signal, a data driving circuit that supplies a data voltage to data lines and inverts a polarity of the data voltage in response to the second polarity control signal, and a gate driving circuit that sequentially supplies a gate pulse to gate lines.