Common Electrode Touch Sensing in LCD Panels
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Solution Overview
Problem
The existing liquid crystal display devices with touch screens have increased thickness and complex manufacturing processes due to the separate formation of touch screens on the liquid crystal panels, leading to higher fabrication costs.
Innovation Solution
Integrating sensing electrodes into the liquid crystal panel, where a common electrode forms an electric field and senses touch positions by using a plurality of first and second common electrodes connected to a sensing line, eliminating the need for a separate touch screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate touch screen is formed on the liquid crystal panel, then touch sensing function is achieved, but the overall thickness of the device is increased
Solution Approach 1:
The patent merges the touch sensing function with the common electrode of the liquid crystal display by forming sensing electrodes (first and second sensing electrodes) on the same substrate as the common electrode. This integration eliminates the need for a separate touch screen layer, thereby reducing the overall device thickness while maintaining touch sensing capability.
Solution Approach 2:
The common electrode is designed to serve dual functions: as the common electrode for liquid crystal driving and as the sensing electrode for touch detection. The first and second sensing electrodes are formed using the same conductive material and processing steps as the common electrode, enabling one structure to perform multiple functions.
2Reliability
If a separate touch screen is formed on the liquid crystal panel, then touch sensing function is achieved, but the fabricating process steps are complicated
Solution Approach 1:
The patent combines the formation of sensing electrodes with the existing common electrode fabrication process. The first and second sensing electrodes are formed using the same conductive material deposition and patterning steps as the common electrode, eliminating the need for separate touch screen fabrication processes and reducing overall manufacturing complexity.
Solution Approach 2:
The same conductive layer and processing steps are used to create both the common electrode and the sensing electrodes. This multi-functional approach allows the manufacturing process to produce multiple functional elements simultaneously, reducing the total number of fabrication steps required.
3Reliability
If a separate touch screen is formed on the liquid crystal panel, then touch sensing function is achieved, but the fabricating cost is increased
Solution Approach 1:
The patent merges the sensing electrode formation with the common electrode fabrication process, using the same conductive material (such as ITO) and deposition techniques. This consolidation eliminates the need for separate material purchases and processing equipment for touch screen fabrication, thereby reducing manufacturing costs.
Solution Approach 2:
The sensing electrodes and common electrode are fabricated using identical materials and processes, maximizing resource utilization and minimizing additional manufacturing expenses. This approach transforms what would be a separate, costly touch screen component into an integrated part of the existing display structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This integration reduces the overall thickness of the liquid crystal display device, simplifies the manufacturing process, and lowers production costs by eliminating the need for a separate touch screen.
Implementation Method 1
an alignment state of liquid crystal molecules in the liquid crystal layer is controlled based on whether or not an electric field is applied thereto, and light transmittance is controlled according to the alignment state of liquid crystal molecules
Implementation Method 2
capacitance between the first sensing electrode 24 and the second sensing electrode 26 is varied at the touched position
Data Source
AI summary
A liquid crystal display device is disclosed, which comprises gate and data lines arranged to cross each other on a substrate to define a pixel region; a pixel electrode formed in the pixel region; a common electrode forming an electric field together with the pixel electrode and sensing a touch of a user; and a sensing line electrically connected with the common electrode, wherein the common electrode includes a plurality of first common electrodes for sensing any one of a touch position of X axis and a touch position of Y axis and a plurality of second common electrodes for sensing the other one of the touch positions of X axis and Y axis, and the sensing line is not electrically connected with the plurality of second common electrodes but electrically connected with the plurality of first common electrodes.