Force Sensor Anisotropic Adhesive Wrinkle Crosstalk
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Solution Overview
Problem
Conventional force sensors face issues with wrinkles in the sensor sheet, foreign matter entry, stress concentration, and crosstalk due to partial bonding of the sensor sheet, which affects accuracy and reliability.
Innovation Solution
A force sensor design featuring a sensor sheet bonded to a substrate using an anisotropic conductive adhesive layer, ensuring full surface contact and minimizing wrinkles and crosstalk, while maintaining insulation properties in the planar direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor sheet is bonded only at the edge portions, then the counter electrode and array electrodes can be kept separate, but wrinkles are generated in the center portion of the sensor sheet and foreign matters enter between the sheet and substrate
Solution Approach 1:
The adhesive layer is segmented into different regions with different bonding properties: a first adhesive region that bonds the sensor sheet to the substrate, and a second adhesive region that does not bond, creating a frame-shaped bonding pattern that prevents wrinkles while avoiding crosstalk
Solution Approach 2:
Different regions of the adhesive layer have different bonding characteristics - the first adhesive region provides bonding to prevent wrinkles and foreign matter entry, while the second adhesive region remains non-bonding to prevent crosstalk between electrodes
2Manufacturing precision
If the entire sensor sheet is bonded, then wrinkles and foreign matter entry are prevented, but the counter electrode and array electrodes conduct with each other through the adhesive layer causing crosstalk
Solution Approach 1:
The adhesive layer is divided into a first adhesive region for bonding and a second adhesive region without bonding, creating a frame-shaped bonding pattern that achieves both full surface contact for wrinkle prevention and electrical isolation for crosstalk prevention
Solution Approach 2:
The adhesive layer exhibits different bonding properties in different locations: the first adhesive region bonds the sensor sheet to prevent wrinkles and foreign matter entry, while the second adhesive region remains non-bonding to maintain electrical isolation between electrodes
3Reliability
If only the edge portions of the sensor sheet are bonded, then crosstalk is avoided, but stress is concentrated on the edge portions and the sensor sheet may be peeled off
Solution Approach 1:
The adhesive layer is segmented into a first adhesive region that bonds the sensor sheet to distribute stress evenly, and a second adhesive region that does not bond to prevent crosstalk, achieving both strong bonding and electrical isolation
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 effectively prevents wrinkles and crosstalk, ensuring accurate force measurement and reducing the risk of sensor peeling, thereby enhancing the reliability and performance of the force sensor.
Implementation Method 1
The first adhesive layer has conductivity in a thickness direction and has insulation properties in a planar direction along a plane
Data Source
AI summary
According to an aspect, a force sensor includes: a sensor sheet having a first surface and a second surface on an opposite side to the first surface; a substrate facing the first surface; a first adhesive layer interposed between the substrate and the sensor sheet and made of an anisotropic conductive material; and a plurality of array electrodes interposed between the substrate and the first adhesive layer and separated from each other. The first surface of the sensor sheet is bonded to the first adhesive layer. The first adhesive layer has conductivity in a thickness direction and has insulation properties in a planar direction along a plane.