Touch Sensor with Asymmetric Electrodes and Pressure-Sensitive Cushion Layer
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Solution Overview
Problem
Existing touch sensors lack the ability to accurately detect touch pressure and position simultaneously, especially when folded, leading to reduced reliability and increased risk of damage from stress.
Innovation Solution
A touch sensor design featuring a base substrate with a sensing unit comprising non-overlapping first and second electrodes on the same layer, combined with a cushion layer that changes permittivity in response to touch pressure, including insulators and conductive particles for enhanced sensitivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional touch sensor structure is used, then the device can detect touch position, but it cannot accurately detect touch pressure simultaneously
Solution Approach 1:
The patent combines position detection and pressure detection functions into a single integrated sensing unit. The first and second electrodes are disposed on the same layer to detect position, while the cushion layer beneath them detects pressure through capacitance changes, eliminating the need for separate sensing layers and achieving both functions simultaneously.
Solution Approach 2:
The cushion layer's permittivity changes in response to applied pressure, which directly modulates the capacitance between the electrodes. This parameter change mechanism allows the system to detect pressure intensity by measuring capacitance variations, achieving accurate pressure detection without additional complex structures.
2Measurement precision
If the sensor structure is made thicker to improve detection capability, then detection accuracy improves, but the device becomes less suitable for folding applications
Solution Approach 1:
The patent employs a thin-film structure where the cushion layer and electrodes are formed as compact, flexible layers suitable for folding devices. The cushion layer acts as a thin compliant element that provides sufficient detection capability while maintaining flexibility and enabling the device to be folded without damage.
3Measurement precision
If overlapping electrodes are used to improve capacitance detection, then sensitivity increases, but the risk of damage from stress increases when folded
Solution Approach 1:
The patent uses asymmetric electrode arrangement where the first and second electrodes are disposed on the same layer rather than overlapping in different layers. This asymmetric configuration maintains sufficient capacitance detection sensitivity while eliminating the stress concentration and damage risks associated with overlapping multi-layer electrode structures in folding applications.
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 solution enables accurate detection of touch position and pressure while reducing the sensor's thickness and improving reliability, especially when folded, by utilizing a cushion layer that changes capacitance in response to pressure, thus enhancing user interaction and device durability.
Implementation Method 1
a cushion layer disposed on at least one surface of the sensing unit and configured to have permittivity change in response to a pressure of the user's touch
Implementation Method 2
wherein a capacitance of the sensing unit is changed by a user's touch
Implementation Method 3
the insulator may include an elastic material elastically deformed by the pressure of the user's touch
Data Source
AI summary
A touch sensor may include a base substrate, a sensing unit including a first electrode and a second electrode provided on a same layer of the base substrate and not overlapping with each other, wherein a capacitance of the sensing unit is changed by a user's touch, and a cushion layer disposed on at least one surface of the sensing unit and configured to have a permittivity change in response to a pressure of the user's touch, wherein the cushion layer may include an insulator and conductive particles and the insulator may include an elastic material elastically deformed by the pressure of the user's touch.