Load Sensor Element Layer Alignment for Stress Suppression
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Solution Overview
Problem
Existing load sensor elements experience stress concentration and deformation at the boundary between covered and exposed portions of the substrate due to repeated loading, leading to potential breakage and inaccurate measurements.
Innovation Solution
A load sensor element design featuring a substrate with a thin-film resistance body sandwiched between an inorganic layer and a reinforcing layer, where the edges of these layers are aligned in the thickness direction to prevent substrate deformation and stress concentration by creating a gap between the exposed substrate and the pedestal, thereby suppressing stress on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the load sensor element is placed on a flat pedestal and load is applied to the inorganic layer, then the measurement function is achieved, but the substrate deforms and stress concentrates on the boundary between covered and exposed portions
Solution Approach 1:
A second inorganic layer is introduced as an intermediary protective element on the back surface of the substrate. This second layer acts as a mediator that distributes and absorbs the stress from pedestal deformation, preventing the stress from concentrating on the substrate boundary and protecting the thin-film resistance body from damage while maintaining measurement functionality
2Force
If the pedestal deforms under load to form a depression, then the load is transmitted to the sensor, but the substrate edge is pushed up and stress concentrates on the boundary
Solution Approach 1:
The second inorganic layer is positioned in advance on the back surface of the substrate to provide cushioning protection. When the pedestal deforms and forms a depression during load application, this pre-positioned second layer absorbs and distributes the mechanical stress before it can reach and damage the thin-film resistance body, thereby maintaining sensor reliability under repeated loading conditions
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 enhances durability and accuracy of load measurements by preventing substrate deformation and stress concentration, allowing for precise detection of load changes and reducing material and procurement costs.
Implementation Method 1
a thin-film resistance body formed of a resistance body whose resistance value is changed in response to a load received from the first layer
Data Source
AI summary
A load sensor element include: a substrate; an inorganic layer that is a first layer provided on a front surface that is a first surface of the substrate, the inorganic layer being configured to cover a part of the substrate; and a thin-film resistance body provided on the front surface. The thin-film resistance body has: a main body portion that is sandwiched between the substrate and the inorganic layer; and a first end portion and a second end portion that are mounted on an exposed portion of the substrate that is not covered by the inorganic layer. The load sensor element includes a reinforcing layer that is a second layer provided on a back surface that is a second surface of the substrate so as to sandwich the substrate together with the inorganic layer. In the load sensor element, the inorganic layer and the reinforcing layer are arranged such that an inorganic-layer first end edge of the inorganic layer that is in contact with the front surface and a reinforcing-layer first end edge of the reinforcing layer that is in contact with the back surface are aligned with each other in the thickness direction of the substrate.