Capacitive Input Structure With Dual Deformation for Linear Force Sensing
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Solution Overview
Problem
Existing input devices experience drastic changes in capacitance due to small operation forces, which can lead to inadequate sensitivity and linearity in capacitance response.
Innovation Solution
The input device incorporates a dual deformable structure in the elastic body, comprising a first deformable part with a higher area change ratio and second deformable parts with a lower area change ratio, which are compressed differently based on the force applied, thereby stabilizing capacitance changes at small forces and enhancing sensitivity and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the elastic body uses a single deformable structure, then the device structure is simple, but the capacitance changes drastically when a small operation force is applied
Solution Approach 1:
The elastic body is divided into multiple deformable parts (first deformable part and second deformable part) with different deformation characteristics. The first deformable part has a higher area change ratio while the second has a lower area change ratio, allowing differential response to applied forces and stabilizing overall capacitance change
Solution Approach 2:
Different regions of the elastic body are赋予 different mechanical properties through the first and second deformable parts. The first deformable part is designed with higher compliance to respond to small forces, while the second deformable part provides structural stability, creating local quality differences that resolve the contradiction
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 configuration maintains stable capacitance changes at small forces while increasing sensitivity and linearity of capacitance response, allowing for precise force detection.
Implementation Method 1
The elastic body includes a first deformable part and a second deformable part on the counter surface. The first deformable part and the second deformable part are configured to be compressed when the operation force is exerted on the pressure receiving part
Implementation Method 2
Each of the plurality of pressure sensors includes electrodes, a pressing part, an insulator, and an elastic body. When the elastic body is pressed by the pressing part, a plurality of projections of the elastic body are crushed. This increases an area where the elastic body and the insulator are in contact with each other, and the capacitance of the pressure sensor thus increases
Data Source
AI summary
An input device includes a fixed electrode layer, an elastic body, a movable member, and an insulating layer. The movable member includes a pressure receiving part on which an operation force is to be exerted. The elastic body includes a first deformable part and at least one second deformable part. When the operation force is exerted on the pressure receiving part, the first deformable part and the at least one second deformable part are compressed. At least at a time point at which the operation force is started to be exerted on the pressure receiving part, a ratio of change in an area of the first deformable part is higher than a ratio of change in an area of the at least one second deformable part.