Two-Axis Physical Quantity Sensor for Cross-Axis Sensitivity Reduction
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Solution Overview
Problem
Existing physical quantity sensors suffer from cross-axis sensitivity, leading to a deterioration in detection accuracy when detecting two-axis physical quantities.
Innovation Solution
The physical quantity sensor is designed with first and second fixed electrode portions and movable electrode portions that extend in perpendicular directions, supported by a movable electrode supporting portion via a spring, to prevent cross-axis sensitivity and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a physical quantity sensor detects two-axis physical quantities using a movable body oscillating parallel to the substrate surface, then the sensor can detect physical quantities in multiple directions, but cross-axis sensitivity occurs causing deterioration in detection accuracy
Solution Approach 1:
The sensor is divided into functionally independent detection units, with each unit dedicated to detecting physical quantities in a specific direction. The first detection unit detects acceleration in the first direction while the second detection unit detects acceleration in the second direction, preventing cross-axis sensitivity by spatial and functional separation of detection capabilities
Solution Approach 2:
Each detection unit is designed with localized electrode arrangements optimized for its specific detection direction. The first detection unit has electrodes configured for first-direction detection, while the second detection unit has electrodes configured for second-direction detection, ensuring that each local region performs its specialized function without interference from other directions
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
The sensor effectively detects physical quantities in perpendicular directions while minimizing cross-axis sensitivity, improving detection accuracy and reducing the influence of substrate warpage.
Implementation Method 1
a first movable electrode supporting portion... configured to support the first movable electrode portion and the second movable electrode portion via a first spring
Implementation Method 2
a physical quantity sensor that changes a gap between a movable electrode portion provided in a movable body and a fixed electrode portion and detects a physical quantity such as acceleration based on a change amount of capacitance
Data Source
AI summary
The embodiment relates to a physical quantity sensor that detects physical quantities in a first direction and a second direction which are in-plane directions and perpendicular to each other. The physical quantity sensor includes: a substrate; a first fixed electrode supporting portion; a first fixed electrode portion; a first movable electrode portion; a second fixed electrode supporting portion; a second movable electrode portion; and a first movable electrode supporting portion. The first movable electrode supporting portion is fixed to the substrate at a movable electrode fixing portion, extends in a first intersecting direction intersecting the first direction and the second direction, and supports the first movable electrode portion and the second movable electrode portion via a first spring.