Touch Substrate Grounding Electrode Non-Overlap Design
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Solution Overview
Problem
In ultrathin and flexible display panels with low ground mass, touch point detection accuracy is compromised due to weak capacitance formed between a finger and the earth, leading to abnormal touch point detection, especially with thicker objects like thumbs, as the mutual capacitance is increased, making it difficult for touch chips to detect touch positions reliably.
Innovation Solution
A touch substrate design featuring a base substrate with a touch driving electrode, a touch sensing electrode, and a grounding electrode, where the grounding electrode is insulated from the other electrodes and arranged to have a non-overlapping region with them, enhancing the capacitance formed between the finger and the earth, thereby improving the detection accuracy by increasing the variable quantity of the total equivalent capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the module stacking structure is thinned to achieve ultrathin and flexible display panels, then the bending and curling requirements are met, but the capacitance formed between finger and earth becomes very small resulting in weak current passing ability and decreased touch point detection accuracy
Solution Approach 1:
The grounding system is segmented into multiple grounding electrodes distributed across the base substrate rather than relying on a single ground connection. This segmentation increases the total grounding area and provides multiple parallel capacitance pathways, thereby enhancing the overall capacitance between finger and earth even in ultrathin configurations.
Solution Approach 2:
The grounding electrode is positioned on the base substrate in a non-overlapping region relative to the touch driving and sensing electrodes, utilizing the planar dimension of the substrate effectively. This spatial arrangement in another dimension (the substrate plane) maximizes grounding area without interfering with the touch electrode functionality, thus improving capacitance without increasing panel thickness.
2Measurement precision
If a grounding electrode is added to increase capacitance between finger and earth, then touch point detection accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
The grounding electrode is merged into the same base substrate that already contains the touch driving and sensing electrodes. By combining multiple electrode functions (touch driving, touch sensing, and grounding) on a single substrate, the overall device structure is simplified despite the addition of grounding functionality. The insulating layer naturally separates these electrodes, eliminating the need for additional complex isolation structures.
Solution Approach 2:
The base substrate serves multiple functions: it supports the touch driving electrodes, touch sensing electrodes, and grounding electrode simultaneously. This multi-functional substrate design reduces the need for separate structural components, thereby improving touch detection accuracy through enhanced grounding while minimizing increases in device complexity.
3Reliability
If the grounding electrode is positioned to maximize capacitance, then the current passing ability is improved, but the orthographic projection overlap with touch electrodes increases causing interference
Solution Approach 1:
The grounding electrode is extracted from the overlapping region with touch electrodes and positioned in a non-overlapping region on the base substrate. This separation removes the harmful interference effect while preserving the grounding function. The grounding electrode is effectively taken out from the conflict zone where it would otherwise interfere with touch electrode operations.
Solution Approach 2:
An insulating layer acts as an intermediary between the grounding electrode and the touch electrodes. This intermediary structure allows the grounding electrode to be positioned close to the touch electrodes to maximize capacitance while preventing direct electrical interference. The insulating layer mediates the interaction, enabling both high current passing ability and minimal interference.
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
The design effectively increases the capacitance between the finger and the earth, allowing for accurate touch point detection even with thicker objects, enhancing the overall accuracy of touch point detection in low ground mass conditions.
Implementation Method 1
capacitance formed by a finger and the earth is very small under the circumstance of the LGM, and the current passing ability of this passage is very weak
Data Source
AI summary
The present disclosure discloses a touch substrate and a display device. The touch substrate includes a base substrate and further includes a touch driving electrode, a touch sensing electrode and a grounding electrode which are located on the base substrate and insulated from one another. An orthographic projection of the grounding electrode on the base substrate and orthographic projections of the touch driving electrode and the touch sensing electrode on the base substrate have a non-overlapping region with each other.