Liquid Crystal Display Data Driving Circuit Polarity Control
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Solution Overview
Problem
Active matrix liquid crystal displays face issues with noise patterns like transverse lines, longitudinal lines, and lattice patterns due to differing data charging characteristics of red, green, and blue subpixels, which are not consistently addressed by existing technologies.
Innovation Solution
A liquid crystal display design where subpixels are successively charged with data voltages of the same polarity through shared data lines, using a data driving circuit to convert digital video data into positive and negative voltages and a gate driving circuit to supply gate pulses, ensuring consistent charging characteristics across subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of data lines and source driver ICs is reduced to 1/2 by time-division supplying data voltage to adjacent liquid crystal cells, then device complexity and cost are reduced, but noise patterns (transverse lines, longitudinal lines, lattice patterns) are generated in the display image
Solution Approach 1:
The patent applies periodic action by time-division multiplexing data voltage supply to adjacent liquid crystal cells through shared data lines. Data voltages are supplied in alternating periods to different groups of cells, enabling the reduction of data lines and source driver ICs to 1/2 of the original number while maintaining proper data charging characteristics through controlled periodic voltage application.
Solution Approach 2:
The patent changes the polarity parameter of data voltages supplied to adjacent liquid crystal cells. By ensuring that data voltages supplied to the same data line have the same polarity during one frame period, the patent eliminates noise patterns while maintaining the benefits of reduced data lines. This parameter control addresses the charging characteristics differences of R, G, and B subpixels.
2Device complexity
If data voltage is time-division supplied to adjacent liquid crystal cells through one data line, then the number of data lines is reduced, but data charging characteristics of R, G, and B subpixels differ causing display defects
Solution Approach 1:
The patent applies local quality by providing different polarity data voltages to different groups of liquid crystal cells connected to the same data line. Specifically, adjacent cells receive data voltages with the same polarity during one frame period, while cells on opposite sides of the data line receive opposite polarities. This localized voltage control ensures consistent data charging characteristics across all subpixels despite sharing data lines.
Solution Approach 2:
The patent controls the polarity parameter of data voltages to ensure consistency in charging characteristics. By maintaining the same polarity for data voltages supplied to the same data line during one frame period, the patent eliminates variations in data charging characteristics among R, G, and B subpixels, thereby preventing display defects while reducing data line count.
3Manufacturing precision
If data voltages of different polarities are supplied to adjacent subpixels, then charging characteristics may be improved, but power consumption of source driver ICs increases
Solution Approach 1:
The patent uses periodic action by maintaining the same polarity for data voltages supplied to the same data line throughout one complete frame period. This periodic voltage supply pattern reduces the switching frequency and operational burden on source driver ICs, thereby reducing their power consumption while still achieving consistent data charging characteristics through the polarity control mechanism.
Data Source
AI summary
A liquid crystal display is disclosed. The liquid crystal display includes a data driving circuit, that converts digital video data into positive and negative data voltages, supplies the positive and negative data voltages to data lines of a liquid crystal display panel, and causes the data voltages supplied to the same data line to have the same polarity during one frame period, and a gate driving circuit sequentially supplying a gate pulse to gate lines of the liquid crystal display panel. Subpixels of the liquid crystal display panel include first and second subpixels positioned adjacent to each other in a horizontal direction. Each of the first and second subpixels is successively charged to the data voltages of two colors.