Vibration Sensor Shield Wiring for Angular Velocity Noise Reduction
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Solution Overview
Problem
Existing electronic devices for detecting angular velocity suffer from degradation in detection accuracy due to electrostatic capacitance-induced noise between electrodes and wiring lines, which affects the reliability of the physical quantity measurement.
Innovation Solution
The electronic device incorporates a vibration element with a shield wiring pattern connected to a constant potential, reducing noise interference by isolating detection and drive signal electrodes, and utilizing a stress relaxation layer to enhance mechanical strength and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the vibration element is disposed on the semiconductor substrate via the stress relaxation layer, then height reduction of the electronic device is achieved, but electrostatic capacitance occurs between electrodes and wiring lines causing noise that degrades detection accuracy
Solution Approach 1:
A shield wiring pattern is introduced as an intermediary element between the electrode and the wiring lines on the substrate. This shield wiring, connected to ground potential, acts as a mediator that blocks the electrostatic capacitance coupling between the electrode and the signal lines, thereby reducing noise while maintaining the compact structure
Solution Approach 2:
The harmful electrostatic capacitance effect is extracted and isolated by introducing a dedicated shield wiring pattern that specifically targets and blocks the noise pathway between the electrode and wiring lines, separating the functional wiring from the noise-generating capacitance
2Ease of manufacture
If wiring lines are disposed on the stress relaxation layer and semiconductor substrate, then electrical connection is achieved, but electrostatic capacitance between wiring lines generates noise
Solution Approach 1:
The shield wiring pattern serves as an intermediary barrier between adjacent wiring lines and electrodes, blocking the electrostatic capacitance coupling that generates noise while preserving the necessary electrical connections for device operation
Solution Approach 2:
The shield wiring pattern is connected to ground potential, creating an equipotential barrier that eliminates voltage differences between adjacent wiring lines and electrodes, thereby reducing electrostatic capacitance and associated noise
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 effectively reduces noise interference, improving the detection accuracy of angular velocity and enhancing the reliability of the electronic device, particularly in reducing capacitive coupling and temperature-dependent noise.
Implementation Method 1
an electrostatic capacitance occurs between an electrode provided to the vibration element and wiring lines on the stress relaxation layer or between wiring lines on the semiconductor substrate and the wiring lines on the stress relaxation layer
Implementation Method 2
a first shield wiring pattern located on the vibration element side of the first wiring pattern, and electrically connected to a constant potential
Data Source
AI summary
An electronic device includes a vibration element having a detection signal electrode and a drive signal electrode, an IC disposed so as to be opposed to the vibration element, a first wiring pattern located between the IC and the vibration element, and electrically connected to the drive signal electrode, and a shield wiring pattern located on the vibration element side of the first wiring pattern, and electrically connected to a constant potential (ground).