Touch Detection Device Parasitic Capacitance Compensation
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Solution Overview
Problem
Existing touch detection systems face challenges in enhancing detection sensitivity to accurately determine the position of an object in space due to interference from parasitic capacitance between detection electrodes and conductors with different electric potentials, which can reduce accuracy.
Innovation Solution
A detecting device with a sensor unit featuring a detection region of arrayed detection electrodes and peripheral electrodes, where drive signals and voltage signals are applied in distinct periods to calculate spatial coordinates by determining the difference between detected values, thereby mitigating the impact of parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection sensitivity is enhanced to accurately detect object position in space, then hover detection function is improved, but parasitic capacitance interference increases which reduces detection accuracy
Solution Approach 1:
The detection process is segmented into multiple periods: a first period for measuring parasitic capacitance (with peripheral electrodes activated) and a second period for measuring actual touch/hover signals (with peripheral electrodes deactivated). This temporal segmentation allows separate measurement and subtraction of parasitic capacitance effects from the total detected signal, thereby improving detection accuracy while eliminating parasitic interference.
Solution Approach 2:
Parasitic capacitance is measured in advance during the first period before the actual touch or hover detection occurs. By performing this preliminary measurement when peripheral electrodes are activated, the system captures the baseline parasitic capacitance value, which is then subtracted from the total signal during the second period to isolate the true object-induced capacitance change.
2Measurement precision
If peripheral electrodes are activated continuously to monitor parasitic capacitance, then parasitic capacitance compensation is improved, but energy consumption increases
Solution Approach 1:
The peripheral electrodes are activated periodically rather than continuously - specifically activated during the first period to measure parasitic capacitance and deactivated during the second period for actual detection. This periodic activation pattern maintains accurate parasitic capacitance compensation while significantly reducing energy consumption compared to continuous activation.
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 approach improves the accuracy of detecting object positions in space by minimizing errors caused by parasitic capacitance, ensuring precise spatial coordinate calculation.
Implementation Method 1
a configuration that detects capacitance generated in detection electrodes to detect the spatial coordinates of the position where the object to be detected is present on the detection region
Implementation Method 2
the detecting device is more likely to be affected by parasitic capacitance generated between the detection electrodes and a conductor having an electric potential different from that of the detection electrodes
Data Source
AI summary
A detecting device includes a sensor unit having a detection region in which a plurality of detection electrodes are arrayed, and a detector configured to supply a drive signal to the detection electrodes and detect a position of an object to be detected in a space on the detection region based on an output value of each of the detection electrodes.