In-cell Touch Panel Common Electrode Reuse for Cost Reduction
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Solution Overview
Problem
The manufacturing of in-cell touch panels involves additional layers and processes, leading to increased production costs and reduced efficiency, despite their advantages in reducing module thickness and cost over add-on mode touch panels.
Innovation Solution
A novel capacitive in-cell touch panel structure reuses the common electrode layer as self-capacitance electrodes, eliminating the need for additional manufacturing processes and integrating a touch sensing chip to detect capacitance value variations, thereby reducing production costs and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional layers and processes are added to manufacture in-cell touch panels, then touch panel performance is improved, but production cost increases and efficiency decreases
Solution Approach 1:
The patent merges the common electrode layer with the self-capacitance electrode function by using the same ITO layer for both display and touch sensing purposes. This integration eliminates the need for separate additional layers, thereby maintaining touch panel performance while improving production efficiency and reducing manufacturing complexity
Solution Approach 2:
The common electrode layer is designed to serve dual functions: as a display electrode for liquid crystal control and as a self-capacitance electrode for touch sensing. This multi-functionality allows the same structural element to fulfill multiple roles, reducing the need for additional manufacturing processes and layers
2Reliability
If additional layers and processes are added to manufacture in-cell touch panels, then touch panel performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the common electrode and self-capacitance electrode into a single ITO layer, eliminating the need for separate additional layers and manufacturing processes. This merging approach maintains touch panel performance while reducing manufacturing cost by simplifying the production workflow
Solution Approach 2:
The common electrode layer is designed to perform both display and touch sensing functions simultaneously. This universal design allows one layer to fulfill multiple roles, reducing the total number of layers that need to be manufactured and thereby lowering overall manufacturing cost
3Productivity
If the common electrode layer is reused as self-capacitance electrodes, then production cost is reduced and efficiency is improved, but additional driving complexity is introduced
Solution Approach 1:
The patent implements time-division driving where the common electrode layer alternates between display mode and touch sensing mode. During display intervals, the electrode functions as a common electrode; during touch intervals, it functions as self-capacitance electrodes. This periodic switching manages driving complexity while maintaining production 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 and enhances efficiency by reusing the common electrode layer as self-capacitance electrodes, allowing for time-division driving between touch and display intervals and potentially integrating display and touch driving chips, while maintaining touch panel performance.
Implementation Method 1
the touch sensing chip is configured to apply common electrode signals to self-capacitance electrodes in a display interval and determine a touch position by detecting capacitance value variation of self-capacitance electrodes in a touch interval
Implementation Method 2
When a human body touches the screen, respective self-capacitance electrodes experience capacitance that is at a value of the fixed value plus the body capacitance
Data Source
AI summary
An in-cell touch panel and a display device are disclosed. The in-cell touch panel includes a top substrate and a bottom substrate disposed oppositely to each other, a common electrode layer disposed on a side of the bottom substrate that faces the top substrate, and a touch sensing chip. The common electrode layer includes a plurality of independent self-capacitance electrodes. The touch sensing chip is configured to apply common electrode signals to self-capacitance electrodes in a display interval and determine touch positions by detecting capacitance value variation of self-capacitance electrodes in a touch interval. No additional process is added in the manufacturing process of the array substrate for the in-cell touch panel, thereby saving production costs and improving production efficiency.