In-Cell Touch Panel Common Electrode Partitioning for Cost Reduction
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Solution Overview
Problem
The manufacturing of in-cell touch panels involves adding new layers, leading to increased production costs and reduced efficiency, which is disadvantageous for improving production efficiency and reducing costs.
Innovation Solution
A novel capacitive in-cell touch panel structure based on High Aperture Ratio-Advanced Super Dimension Switching (H-ADS) technology, where the common electrode layer is partitioned into independent self-capacitance electrodes along strip-like slits, allowing the reuse of the common electrode layer as self-capacitance electrodes, eliminating the need for additional manufacturing processes and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If new layers are added to manufacture in-cell touch panels, then touch functionality is achieved, but production costs increase and production efficiency decreases
Solution Approach 1:
The common electrode layer is designed to serve dual purposes: it functions as the common electrode for LCD display operation and simultaneously as the self-capacitance electrode for touch sensing. This multi-functionality eliminates the need for separate touch electrode layers, thereby reducing manufacturing complexity and improving production efficiency while maintaining full touch functionality
Solution Approach 2:
The patent merges the common electrode layer of the LCD with the self-capacitance electrode layer of the touch panel into a single integrated layer. By combining these two previously separate functional layers, the invention reduces the total number of layers to be manufactured, directly addressing the contradiction between achieving touch functionality and maintaining high production efficiency
2Reliability
If new layers are added to manufacture in-cell touch panels, then touch functionality is achieved, but production costs increase
Solution Approach 1:
The common electrode layer performs both display and touch sensing functions, eliminating the need for additional touch-specific electrode layers. This reduces material costs and manufacturing process costs while ensuring complete touch functionality is achieved through the self-capacitance principle
Solution Approach 2:
By merging the common electrode and self-capacitance electrode into one layer, the invention reduces the total number of manufacturing steps, materials required, and process complexity, thereby lowering production costs while maintaining full touch functionality
3Productivity
If the common electrode layer is reused as self-capacitance electrodes, then additional manufacturing processes are eliminated, but signal interference between display and touch may occur
Solution Approach 1:
The patent implements time-division multiplexing where the common electrode layer alternates between serving as the common electrode for display and as the self-capacitance electrode for touch sensing. By periodically switching functions in different time periods, the invention eliminates signal interference while maintaining manufacturing efficiency benefits
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 approach saves production costs, improves production efficiency, and maintains light transmittance efficiency by avoiding light leakage and minimizing interference between display and touch signals, while ensuring high touch accuracy and resolution.
Implementation Method 1
an in-cell touch panel detects the touch position of a finger based on the mutual capacitance or self-capacitance principle. As for the self-capacitance principle, it is possible to provide a plurality of self-capacitance electrodes disposed in the same layer and insulated from each other in a touch panel. When a human body does not touch the screen, each self-capacitance electrode experiences capacitance of a fixed value. When the human body touches the screen, corresponding self-capacitance electrodes experience capacitance of the fixed value plus the human body capacitance.
Implementation Method 2
gate lines and data lines formed on a substrate to be intersected with each other, a plurality of pixel electrodes formed at intersections between the gate lines and the data lines, and a common electrode formed to overlap the plurality of pixel electrodes through an insulating film disposed between the common electrode and the plurality of pixel electrodes
Data Source
Figure 1
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Figure 3a
AI summary
An in-cell touch panel and a display device are disclosed, a common electrode layer (03) is reused as self-capacitance electrodes (05) in accordance with self-capacitance principle. A pattern of common electrode layer (03) is designed such that the common electrode layer (03) is partitioned into a plurality of mutually independent self-capacitance electrodes (05) along strip-like slits and a direction crossing the slits. The touch sensing chip (04) can determine a touch position by detecting capacitance value variation of self-capacitance electrodes in a touch peirod. The in-cell touch panel can save production costs and improve production efficiency, and also can avoid light leakage caused by cutting common electrode layer and influence on display effect.