Pressure Sensor Resistor Segmentation for Stable Output
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Solution Overview
Problem
Conventional pressure sensitive sensors struggle to stably obtain good output characteristics due to the increasing contact area between electrodes, leading to unstable resistance value changes with applied load.
Innovation Solution
A pressure sensitive sensor design featuring a first substrate with a resistor, comb tooth patterns, and wiring patterns, where the resistor has a higher electrical resistivity than the wiring and comb tooth patterns, and is positioned not to overlap with the connecting body in plan view, allowing the resistance value between the wiring patterns to change with applied load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrodes are disposed to come into direct contact with each other when the upper circuit board is pushed, then the contact area increases and the resistance value decreases, but the output characteristics cannot be stably obtained
Solution Approach 1:
The electrode is divided into a pressure-sensitive resistor portion and a comb-shaped electrode portion. The pressure-sensitive resistor changes resistance based on contact area, while the comb-shaped electrode maintains stable electrical connection, separating the sensing function from the connection function to ensure stable output characteristics
Solution Approach 2:
A resin layer is introduced as an intermediary between the pressure-sensitive resistor and the comb-shaped electrode. This resin layer ensures stable electrical connection while allowing the pressure-sensitive resistor to maintain consistent contact characteristics with the opposing electrode, resolving the instability issue
2Measurement precision
If the contact area between electrodes increases with pushing force, then the resistance value changes, but good output characteristics may not be stably obtained
Solution Approach 1:
Different portions of the electrode structure are assigned different functions with appropriate material properties. The pressure-sensitive resistor portion is designed to change resistance locally based on contact area, while other portions maintain stable electrical properties, ensuring both sensitivity and stability
Solution Approach 2:
The electrode structure is designed to dynamically adapt during pressing: the pressure-sensitive resistor portion dynamically changes its electrical properties in response to contact area changes, while the overall structure maintains stable geometric relationships to ensure consistent output characteristics
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 design enables stable and reliable output characteristics by preventing direct contact between the resistor and the connecting body, thus maintaining consistent resistance value changes with varying loads.
Implementation Method 1
a resistance value between the first wiring pattern and the second wiring pattern changes according to the load applied to the pushing part
Data Source
AI summary
A pressure sensitive sensor includes: a first substrate; a resistor disposed on the first substrate; a first wiring pattern disposed on the first substrate and connected to the resistor; first comb tooth patterns disposed on the first substrate and connected to the resistor; a pusher includes a pushing part and a connecting body electrically connected to the first comb tooth patterns by pushing of the pushing part; and a second wiring pattern disposed on the first substrate and electrically connected to the connecting body by pushing of the pushing part. A material of the resistor has an electrical resistivity higher than electrical resistivities of materials of the first wiring pattern, the first comb tooth patterns, the connecting body, and the second wiring pattern. The resistor does not overlap the connecting body in a plan view.