Liquid Crystal Display Polarity Inversion Boundary Noise Control
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Solution Overview
Problem
Liquid crystal displays using horizontal 2-dot inversion schemes experience boundary noise due to uneven polarity inversion, leading to picture quality issues, especially when frame rate control is applied, causing luminance differences and flicker.
Innovation Solution
A liquid crystal display system with a timing controller generating synchronized or opposing polarity control signals for source drive ICs during horizontal 1-dot and 2-dot inversion, ensuring continuous polarity inversion across all source drive ICs, eliminating boundary noise by adaptive control based on image patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If horizontal 2-dot inversion scheme is used, then polarity inversion is achieved, but boundary noise occurs due to uneven polarity inversion at source drive IC boundaries
Solution Approach 1:
The patent applies local quality by generating different polarity control signals for different source drive ICs. Specifically, the timing controller generates a first polarity control signal for first source drive ICs and a second polarity control signal for second source drive ICs, where these signals have different phases. This allows adjacent source drive ICs to use different inversion schemes (1-dot vs 2-dot inversion), ensuring that polarity inversion occurs uniformly across the boundary between source drive ICs and eliminating boundary noise caused by uneven polarity distribution.
2Productivity
If frame rate control is applied, then display timing is adjusted, but luminance differences and flicker occur due to common voltage shift
Solution Approach 1:
The patent applies dynamics by making the polarity control adaptive and changeable based on display conditions. The timing controller dynamically adjusts the polarity control signals supplied to different source drive ICs, allowing the system to switch between different inversion schemes as needed. This dynamic control ensures that polarity inversion remains consistent even when frame rate control is applied, preventing common voltage shift and maintaining stable luminance without flicker.
3Productivity
If multiple source drive ICs are used, then data output capacity is increased, but polarity inversion becomes uneven at the boundaries between ICs
Solution Approach 1:
The patent applies local quality by assigning different polarity control characteristics to different source drive ICs. The timing controller generates a first polarity control signal with a first phase for first source drive ICs and a second polarity control signal with a second phase for second source drive ICs. This causes adjacent source drive ICs to employ different inversion schemes (one using 1-dot inversion, the other using 2-dot inversion), which ensures that polarity inversion occurs uniformly across the boundary between ICs, maintaining stable polarity distribution while preserving the increased data output capacity provided by multiple ICs.
Data Source
AI summary
A liquid crystal display includes: a liquid crystal display panel including a plurality of data lines and a plurality of gate lines crossing each other; a first source drive IC for outputting a data voltage to the data lines and inverting the polarity of the data voltage in response to a first polarity control signal; a second source drive IC for outputting the data voltage to the data lines and inverting the polarity of the data voltage in response to a second polarity control signal; and a timing controller for generating the first and second polarity control signals in the same phase when the source drive ICs output data voltages whose polarity is inverted by horizontal 1-dot inversion and generating the first and second polarity control signals in the opposite phase to each other when the source drive ICs output data voltages whose polarity is inverted by horizontal 2-dot inversion.