Touch Sensor Electrode Layout With Active Shield Wiring
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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 and external electrical influences, particularly near the edges and periphery, which affect detection accuracy.
Innovation Solution
The sensor module employs a matrix arrangement of sensor electrodes with sensor and first active-shield wirings, where sensor wirings are sandwiched by first active-shield wirings in the row direction, and additional auxiliary and dummy wirings are used to reduce parasitic capacitance, maintaining high conductivity and transparency while enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor wirings are arranged to connect sensor electrodes to terminals, then electrical connectivity is achieved, but parasitic capacitance increases and detection accuracy deteriorates
Solution Approach 1:
The patent introduces active-shield wirings as intermediary elements between sensor wirings and sensor electrodes. These active-shield wirings are driven at the same potential as the sensor electrodes, creating an equipotential region that acts as a mediator to prevent parasitic capacitance formation between sensor wirings and electrodes, thus maintaining both connectivity and detection accuracy
Solution Approach 2:
The patent converts the harmful parasitic capacitance effect into a beneficial shielding effect by using active-shield wirings driven at sensor electrode potential. The presence of these shield wirings, which would normally contribute to parasitic capacitance, instead creates a controlled electric field that cancels out unwanted capacitive coupling, turning the harmful effect into a protective shielding mechanism
2Measurement precision
If additional shield wirings are added to reduce parasitic capacitance, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple wirings into integrated structures. The active-shield wirings are combined with the sensor wiring layout such that they share common routing paths and terminal connections where possible. This merging approach reduces the overall number of discrete wiring elements and simplifies the terminal structure while maintaining the parasitic capacitance reduction effect
Solution Approach 2:
The active-shield wirings serve multiple functions simultaneously: they act as electrical shields to reduce parasitic capacitance, provide additional electrical connectivity paths, and can be integrated with existing terminal structures. This multi-functionality reduces the need for separate dedicated shield structures, thereby limiting the increase in device complexity
3Measurement precision
If sensor electrodes are arranged in dense matrix configuration, then detection resolution improves, but external electrical interference increases
Solution Approach 1:
The active-shield wirings act as intermediary protective elements between the dense sensor electrode matrix and external electrical interference. By being driven at sensor electrode potential, they create equipotential barriers that mediate the interaction between external electric fields and the sensitive sensor electrodes, reducing capacitive coupling from external sources
Solution Approach 2:
The patent applies preliminary anti-action by pre-establishing the active-shield wirings at sensor electrode potential before external interference occurs. This preemptive shielding configuration creates a protective electric field that actively counteracts external electrical interference before it can affect the sensor electrodes, thereby maintaining detection resolution in dense configurations
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, ensuring accurate identification of input means' positions even near the edges and periphery, maintaining high detection accuracy and reducing external electrical 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 and external electrical influences
Implementation Method 2
Each of the plurality of sensor wirings electrically connects a corresponding one of the plurality of sensor electrodes to a corresponding one of the plurality of first terminals
Implementation Method 3
a control circuit mounted over the connector and configured to sense a potential fluctuation of the plurality of sensor electrodes
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.