Pressure Sensor Electrode Wiring for Position-Independent Resistance
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Solution Overview
Problem
Pressure sensors face variations in conduction path resistance due to differing pressing positions, leading to inconsistent force detection, particularly in larger sensors where electrode wiring resistance ratios significantly impact measurement accuracy.
Innovation Solution
The pressure sensor design includes a configuration where the second wiring section extends to ensure equal conduction path resistance between output terminals of the first and second wiring sections, regardless of the pressing position, by adjusting the length of the wiring paths to maintain consistent resistance across different combinations of electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the sensor size is increased to cover larger pressing areas, then the sensing area is improved, but the conduction path resistance of the electrode wiring becomes large causing detection accuracy to deteriorate
Solution Approach 1:
The patent applies local quality by making the wiring section have different properties from the electrode patterns. Specifically, the wiring section is designed with higher resistance than the electrode patterns, allowing the system to compensate for position-dependent resistance variations. This localized property change in the wiring section enables accurate pressure detection across the entire large sensing area by balancing the total conduction path resistance regardless of where pressure is applied.
2Adaptability or versatility
If the electrode wiring length is increased to cover larger pressing positions, then the sensing range is improved, but the conduction path resistance becomes large causing measurement precision to deteriorate
Solution Approach 1:
The patent applies parameter changes by intentionally designing the wiring section with a specific resistance value that is higher than the electrode patterns. This parameter change in the wiring section's resistance allows the total conduction path resistance to remain substantially equal across different pressing positions, thereby maintaining measurement precision while extending the sensing range to cover larger pressing areas.
3Reliability
If the wiring section resistance is increased to compensate for position-dependent variations, then detection consistency is improved, but the overall conduction path resistance increases
Solution Approach 1:
The patent applies local quality by making the wiring section have different properties from the electrode patterns. Specifically, the wiring section is designed with higher resistance than the electrode patterns, allowing the system to compensate for position-dependent resistance variations. This localized property change in the wiring section enables accurate pressure detection across the entire large sensing area by balancing the total conduction path resistance regardless of where pressure is applied.
Solution Approach 2:
The patent applies parameter changes by intentionally designing the wiring section with a specific resistance value that is higher than the electrode patterns. This parameter change in the wiring section's resistance allows the total conduction path resistance to remain substantially equal across different pressing positions, thereby maintaining measurement precision while extending the sensing range to cover larger pressing areas.
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 achieves a variation in conduction path resistance of no more than 10% of the pressure-sensitive resistance, even under maximum load, ensuring accurate and consistent force detection across various pressing positions.
Implementation Method 1
a pressure-sensitive conductor, a first electrode pattern, and a second electrode pattern, a first wiring section, and a second wiring section... when adjacent first electrode and second electrode conduct with each other via the pressure-sensitive conductor
Data Source
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AI summary
[Problem] To improve the precision of detecting a pressing force with a pressure sensor. [Solution] In a pressure sensor 3, a pressure-sensitive layer 17 faces a first electrode pattern 21A and a second electrode pattern 21B with a space interposed therebetween. The first electrode pattern 21A includes a plurality of first electrode sections 31, a first interconnecting section 33 that interconnects the plurality of first electrode sections 31, and a first wiring section 35 that extends from a first end 37 of the first interconnecting section 33. The second electrode pattern 21B includes a plurality of second electrode sections 41 disposed alternately with the first electrode sections 31, a second interconnecting section 43 that interconnects the plurality of second electrode sections 41, and a second wiring section 45 that extends from a second end 49 of the second interconnecting section 43. The second wiring section 45 extends such that the resistance of the conduction path between an output terminal of the first wiring section 35 and an output terminal of the second wiring section 45 is substantially the same for any adjacent pairs of the first electrode sections 31 and the second electrode sections 41 when the first electrode section 31 and the second electrode section 41 conduct with each other via the pressure-sensitive layer 17.