Angular Velocity Sensor Electrode Segmentation for Sensitivity
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Solution Overview
Problem
Existing angular velocity sensors face challenges in maintaining detection sensitivity due to unintended arm bending during manufacturing, leading to reduced sensitivity and limited adjustment range of charge output.
Innovation Solution
A sensor element configuration with a base part, drive and detection vibrating arms, and adjustment electrodes of opposite polarities, allowing for adjustment of sensor output by removing parts of these electrodes to achieve desired reference values, and incorporating mass adjustment parts to align resonance frequencies and increase potential differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tuning fork is formed by etching processing of a substrate, then the manufacturing process is simple, but the dimensions of the tuning fork deviate from design due to etching anisotropy and process variations
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the substrate before etching, and using this film as a mask to control the etching process. This preliminary preparation ensures that the etching proceeds with greater precision and reduces dimensional deviations caused by etching anisotropy and process variations.
Solution Approach 2:
The patent introduces a protective film as an intermediary layer between the substrate and the etching process. This film acts as a mediator that controls the etching depth and pattern, thereby improving the dimensional accuracy of the tuning fork while maintaining the simplicity of the etching process.
2Adaptability or versatility
If one electrode of the detection part is partially removed to adjust charge output, then the sensor output can be adjusted, but the adjustment range is limited
Solution Approach 1:
The patent segments the detection electrodes into multiple independent electrodes rather than treating them as a single unit. By partially removing or modifying individual electrodes, the system achieves a wider adjustment range for the sensor output while maintaining the overall detection function.
Solution Approach 2:
The patent makes the electrode configuration dynamic by allowing selective removal or modification of electrode portions based on the required sensor output characteristics. This dynamic adjustment capability expands the adaptability of the sensor while managing the complexity through controlled modifications.
3Reliability
If the arm bends in a direction different from the drive direction, then the sensor may detect unintended signals, but detection sensitivity is reduced
Solution Approach 1:
The patent applies preliminary anti-action by designing the tuning fork structure and electrode arrangement to counteract unintended bending effects before they affect the measurement. The protective film and controlled etching process prevent dimensional deviations that would cause off-axis bending, thereby maintaining both signal accuracy and detection sensitivity.
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
Enhances detection sensitivity and adjustment range of sensor output, ensuring accurate measurements and reliability in angular velocity detection.
Implementation Method 1
a drive part and a detection part including a piezoelectric thin film inserted between a pair of electrodes are respectively formed in each arm. Under the drive condition, when the arm is subjected to an angular velocity around an axis line along the extension direction thereof, the arm bends in a direction orthogonal to the above described drive direction by Coriolis force, and electric charge in response to the amount of bending is detected from the pair of electrodes of the detection part.
Implementation Method 2
by applying a voltage to the pair of electrodes of the drive part, the arm is flexurally vibrated (driven).
Implementation Method 3
when the arm is subjected to an angular velocity around an axis line along the extension direction thereof, the arm bends in a direction orthogonal to the above described drive direction by Coriolis force
Data Source
AI summary
A sensor element has drive vibrating arms drive-vibrating by energization, adjustment vibrating arms vibrating with the drive vibrations of the drive vibrating arms, detection electrodes outputting charge in response to physical quantities applied to the drive vibrating arms, first electrodes provided on the adjustment vibrating arms, electrically connected to the detection electrodes, and outputting charge with the vibrations of the adjustment vibrating arms, and a pair of second electrodes provided on the adjustment vibrating arms, electrically connected to a pair of detection electrodes, and outputting charge having an opposite polarity to that of the first electrodes with the vibrations of the adjustment vibrating arms.