Gyro Sensor Beam Groove for Quadrature Signal Reduction
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Solution Overview
Problem
Existing gyro sensors manufactured using dry etching techniques often result in non-ideal cross-sectional shapes of the elastic beams, leading to unwanted vibration components and increased quadrature signals, which degrade detection accuracy.
Innovation Solution
The implementation of a physical quantity sensor with beams having a groove on their surface, where the wall thickness ratio of the sidewalls is maintained between 0.9 and 1.1, and the groove is preferably centered and recessed, with a curved shape, to stabilize the beam's structure and reduce quadrature signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching technique is used to manufacture the sensor element, then manufacturing efficiency is improved, but the cross-sectional shape of the elastic beam deviates from ideal rectangular shape resulting in increased quadrature signals
Solution Approach 1:
The patent changes the geometric parameters of the elastic beam by introducing a groove structure. This groove modifies the mass distribution and stiffness characteristics of the beam, compensating for the shape deviations caused by dry etching. The groove dimensions and position are specifically designed to counteract the parasitic vibrations while maintaining compatibility with the dry etching manufacturing process.
2Ease of manufacture
If the cross-sectional shape of the elastic beam is non-ideal due to processing errors, then manufacturing is simplified, but unwanted vibration components increase reducing detection accuracy
Solution Approach 1:
The patent converts the harmful effect of non-ideal cross-sectional shapes into a benefit by strategically placing a groove in the elastic beam. The groove creates intentional asymmetry that counterbalances the unintended asymmetry from processing errors. This transforms the manufacturing tolerance issue into a controlled geometric feature that actively reduces quadrature signals and improves measurement accuracy.
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 the increase of quadrature signals, thereby enhancing the detection accuracy of angular velocity and maintaining the strength of the beam against bending forces.
Implementation Method 1
Wall thicknesses on a main surface of two sidewalls facing each other of the groove in a direction orthogonal to a longitudinal direction of the beam satisfy 0.9≤T1/T2≤1.1
Implementation Method 2
a vibrator supported to the fixed part via an elastic beam (support beam)
Implementation Method 3
a voltage applied to the fixed comb-like electrode generates an electrostatic force between the movable electrode and the fixed comb-like electrode and this electrostatic force causes the vibrator to vibrate in direction of an X-axis
Implementation Method 4
An angular velocity about a Z-axis (or Y-axis) acting on the vibrator in such a vibrating state generates a Coriolis force and this Coriolis force causes the vibrator to vibrate in the direction of the Y-axis (or Z-axis)
Data Source
AI summary
A gyro sensor includes a plurality of beams connected via a turnaround part. A groove is provided on a main surface of at least one beam of the plurality of beams. Wall thicknesses on the main surface of two sidewalls facing each other of the groove in a direction orthogonal to a longitudinal direction of the beam satisfy 0.9≤T1/T2≤1.1, where T1 is the wall thickness of one sidewall and T2 is the wall thickness of the other sidewall.