LCD Pixel Circuit Group Selection for Gray Level Stability
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Solution Overview
Problem
Liquid crystal display devices experience deviations in gray levels due to biased potentials written to pixel circuits, especially when driving multiple rows of pixel circuits simultaneously, leading to unstable common electrode potentials and incorrect gray level display.
Innovation Solution
A liquid crystal display device with a selection unit that sequentially selects pixel circuits in groups, using different data lines and scanning lines, and a control unit that changes pixel circuit connections and data signal polarities to overlap and invert pixel circuit operations at specific frame intervals, thereby stabilizing the common electrode potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple rows of pixel circuits are driven simultaneously to increase frame rate, then productivity is improved, but manufacturing precision deteriorates due to gray level deviation
Solution Approach 1:
The patent implements periodic switching between different scanning line selection patterns. Specifically, it alternates between selecting even-numbered scanning lines and odd-numbered scanning lines in a periodic manner. This periodic action ensures that over time, all pixel circuits receive data signals with appropriate polarity compensation, thereby maintaining accurate gray levels while enabling simultaneous driving of multiple pixel circuit rows to achieve high frame rates.
2Loss of time
If multiple scanning lines are selected simultaneously to reduce scanning period, then time is saved, but reliability deteriorates due to unstable common electrode potential
Solution Approach 1:
The patent employs a feedback mechanism where the selection of scanning lines is dynamically adjusted based on the polarity of data signals. The system monitors the polarity requirements of pixel circuits and switches between different scanning line selection patterns (even-numbered vs. odd-numbered) to ensure that the common electrode potential remains stable. This feedback-based switching maintains reliability by preventing potential instability while enabling simultaneous driving of multiple scanning lines to reduce the horizontal scanning period.
3Manufacturing precision
If data signals with large absolute values are written to pixel circuits of one polarity, then manufacturing precision is improved for those pixels, but object-generated harmful factors worsen due to common variation
Solution Approach 1:
The patent applies inversion by switching between two complementary scanning line selection patterns. When even-numbered scanning lines are selected, pixel circuits with positive polarity receive data signals. When odd-numbered scanning lines are selected, pixel circuits with negative polarity receive data signals. This inversion strategy ensures that over time, the influence of large absolute value data signals is distributed evenly across all pixel circuits regardless of polarity, thereby preventing common variation while maintaining writing accuracy for each pixel circuit.
Data Source
AI summary
A liquid crystal display device includes: a plurality of pixel circuits which is arranged in a matrix shape; a plurality of data lines; a selection unit which sequentially selects the plurality of pixel circuits for every group which is fewer in number than the number of rows of the pixel circuits; a control unit which sequentially changes the pixel circuits included in the groups; and a data signal supply unit which outputs a data signal to each data line. Each of the plurality of sequentially selected pixel circuits is connected to each of the different data lines.