Sensor Module Active-Shield Wiring for Low-Parasitic Touch Detection
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Solution Overview
Problem
Existing non-contact type touch sensor modules face challenges in accurately identifying the position of an input means due to parasitic capacitance, which affects detection accuracy, especially near the edges and periphery of the sensor region.
Innovation Solution
The sensor module incorporates a matrix of sensor electrodes with sensor wirings and first active-shield wirings arranged in a specific pattern, where each sensor wiring is sandwiched by two first active-shield wirings in the row direction, and optionally with auxiliary and dummy wirings, to reduce parasitic capacitance and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-contact type sensor modules are used to enable hover detection, then input flexibility is improved, but detection accuracy deteriorates due to parasitic capacitance
Solution Approach 1:
Active-shield wirings are introduced as intermediary elements between sensor electrodes and external environment. These shield wirings act as mediators that block parasitic capacitance pathways while allowing the sensor to detect genuine input signals, thus resolving the contradiction between non-contact input capability and detection accuracy
Solution Approach 2:
The harmful parasitic capacitance effect is extracted and isolated by introducing separate active-shield wirings that specifically target and counteract the parasitic capacitance generated by sensor wirings, allowing the main sensor function to operate accurately without being contaminated by parasitic effects
2Reliability
If sensor wirings are extended to connect sensor electrodes to terminals, then electrical connectivity is improved, but parasitic capacitance increases
Solution Approach 1:
Active-shield wirings serve as intermediary conductors that run parallel to sensor wirings. These shield wirings are driven at the same potential as adjacent sensor electrodes, creating an equipotential barrier that prevents parasitic capacitance from forming between sensor wirings and other conductive elements, thus maintaining electrical connectivity while eliminating harmful capacitance
Solution Approach 2:
The active-shield wirings are driven at the same potential as adjacent sensor electrodes, creating equipotential regions that eliminate potential differences and thus prevent parasitic capacitance formation. This equipotential shielding approach allows sensor wirings to extend throughout the sensor region without generating harmful capacitive effects
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 significantly reduces parasitic capacitance, enabling accurate identification of the input means' position across the sensor region, including edges, by maintaining consistent potential fluctuations and minimizing noise interference.
Implementation Method 1
Existing non-contact type touch sensor modules face challenges in accurately identifying the position of an input means due to parasitic capacitance
Data Source
AI summary
Disclosed is a sensor module including a plurality of sensor electrodes, a sensor region, a frame region, a plurality of first terminals and a plurality of second terminals, a plurality of sensor wirings, and a plurality of first active-shield wirings. The plurality of sensor electrodes is arranged in a matrix shape having n rows including a first row to an nth row and m columns including a first column to an mth column. The sensor region encompasses the plurality of sensor electrodes. The frame region surrounds the sensor region. The plurality of first terminals and the plurality of second terminals are arranged in a region opposite to the nth row located in the frame region. The plurality of first active-shield wirings is electrically independent from the plurality of sensor electrodes.