Segmented Common Electrode Crosstalk Reduction
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Solution Overview
Problem
Liquid crystal display devices face image quality deterioration due to high resistance and large time constants in common electrodes, leading to crosstalk and difficulties in driving the common electrode, especially with long power supply lines.
Innovation Solution
A display device configuration with common drive electrodes extended along signal lines, allowing simultaneous scanning and independent signal supply to each display element, reducing crosstalk and improving driving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a common electrode is formed using ITO to maintain optical transparency, then the electrode can be transparent, but the resistance increases and time constant becomes larger
Solution Approach 1:
The patent applies a composite structure by forming a transparent conductive film (ITO) over a reflective electrode (Aluminum). This composite configuration combines the transparency of ITO with the low resistance of aluminum, achieving both optical transparency and electrical conductivity requirements simultaneously.
2Illumination intensity
If the common electrode has high resistance and large time constant, then the electrode can maintain optical transparency, but crosstalk occurs between adjacent pixels and image quality deteriorates
Solution Approach 1:
The composite structure of transparent conductive film over reflective electrode reduces the overall resistance of the common electrode system. This lower resistance minimizes voltage drops and signal interference, thereby suppressing crosstalk between adjacent pixels while maintaining optical transparency.
3Device complexity
If the drive circuit is positioned far from the common electrode, then the device structure is simplified, but the output impedance increases due to long power supply lines
Solution Approach 1:
The patent divides the common electrode into multiple segments along the row direction, with each segment independently controllable. This segmentation allows drive circuits to be positioned at different locations, reducing the length of power supply lines to each segment and thereby lowering output impedance while maintaining simplified overall device structure.
Solution Approach 2:
The patent extends the common electrode in the row direction and divides it into multiple segments, adding a spatial dimension to the electrode structure. This dimensional change enables multiple drive circuits to serve different segments, reducing the distance between drive circuits and electrodes, and thus lowering output impedance.
4Device complexity
If the common electrode is driven with high output impedance, then the device structure can be simplified, but driving the common electrode becomes difficult and image quality deteriorates
Solution Approach 1:
By segmenting the common electrode into multiple independently controllable parts, the patent enables each segment to be driven with lower impedance. This segmentation makes it easier to drive each segment effectively while maintaining overall device structure simplicity, thereby improving ease of operation without compromising structure.
Data Source
AI summary
A display device includes a plurality of signal lines that are so juxtaposed as to be extended along one direction, a plurality of common drive electrodes that are so juxtaposed as to be extended along the signal lines, and a plurality of display elements that are each connected to a respective one of the plurality of signal lines and are each connected also to the common drive electrode that makes a pair with the connected signal line. Scan driving of the plurality of display elements is performed in the direction of the signal lines.