Force Sensor Fixing Terminal Overlap Design
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Solution Overview
Problem
Small force sensors face reduced load-carrying capacity and increased damage risk when size is minimized, leading to reduced sensitivity and potential damage under heavy loads.
Innovation Solution
A force sensor configuration where the displaceable portion is entirely within the pressure-receiving member, with a fixing terminal overlapping the pressure-receiving member, ensuring that excessive force is absorbed without direct transmission to the displaceable portion, maintaining sensitivity and load-carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the pressure-receiving member is reduced to minimize sensor size, then the sensor size is reduced, but the load-carrying capacity is reduced and the pressure-receiving member is damaged easily
Solution Approach 1:
The invention introduces a vertical stacking dimension to resolve the size-strength contradiction. The pressure-receiving member is positioned above the sensor substrate in the vertical direction, allowing the sensor to detect loads through vertical displacement while maintaining a compact horizontal footprint. This dimensional arrangement enables small sensor size while preserving load-carrying capacity through proper structural hierarchy.
Solution Approach 2:
The sensor substrate acts as an intermediary between the pressure-receiving member and the base substrate. It receives vertical displacement from the pressure-receiving member under load and transmits this displacement to the piezoelectric resistors for detection. This intermediary structure allows the pressure-receiving member to maintain strength while the sensor substrate provides the displaceable function.
2Volume of moving object
If the size of the displaceable portion is reduced to minimize sensor size, then the sensor size is reduced, but the sensitivity is reduced
Solution Approach 1:
The invention applies local quality by concentrating the displaceable function in a specific region of the sensor substrate while maintaining overall structural integrity. The displaceable portion is strategically positioned to maximize displacement under load, and the piezoelectric resistors are placed at locations that optimize sensitivity to this displacement, achieving high measurement precision in a compact form.
Solution Approach 2:
The invention optimizes sensitivity by carefully controlling the displacement parameters of the displaceable portion. The sensor substrate is designed with specific thickness and material properties that enable adequate displacement under load while maintaining small overall size. The piezoelectric resistors are positioned to maximize the change in electrical resistance in response to the displacement, achieving high sensitivity despite the small scale.
3Force
If the pressure-receiving member receives heavy load, then the load detection capability is improved, but other elements including sensor substrate and base substrate may be damaged
Solution Approach 1:
The invention provides beforehand cushioning through the sensor substrate that absorbs and distributes the load from the pressure-receiving member. The sensor substrate is designed to deform elastically under heavy loads, preventing direct transmission of excessive forces to the base substrate and other sensitive elements. This protective mechanism allows the sensor to handle heavy loads without damaging other components.
Solution Approach 2:
The invention segments the load path into distinct functional layers: the pressure-receiving member receives the load, the sensor substrate detects it through controlled displacement, and the base substrate provides structural support. This segmentation allows each element to be optimized for its specific function, with the sensor substrate acting as a buffer that protects other elements from damage while enabling load detection.
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 prevents excessive bending of the displaceable portion, maintains sensitivity of piezoelectric resistors, and enhances the load-carrying capacity of the force sensor, ensuring effective load detection even under heavy loads.
Implementation Method 1
A plurality of piezoelectric resistors are configured to electrically detect an amount of displacement of the displaceable portion
Data Source
AI summary
A force sensor includes a pressure-receiving member; a sensor substrate including a displaceable portion to be displaced under a load received by the pressure-receiving member, and piezoelectric resistors configured to electrically detect an amount of displacement of the displaceable portion; a base substrate having a sensor-mounting surface, and including electrical wiring portions electrically connected to the piezoelectric resistors; and a package substrate having a substrate-mounting surface and a pad surface provided with pad electrodes. The pressure-receiving member, the sensor substrate, and the base substrate are stacked in a normal direction to the substrate-mounting surface. When seen in the normal direction, an entirety of the displaceable portion is located within the pressure-receiving member. The pad surface is provided with, when seen in the normal direction, a fixing terminal at least a part of which overlaps at least a part of a first area that coincides with the pressure-receiving member.