Physical Quantity Sensor With Localized Penetration Holes
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Solution Overview
Problem
Existing acceleration sensors lack sufficient mechanical strength to withstand excessive acceleration, leading to potential damage and reduced accuracy in detecting vibrations.
Innovation Solution
The physical quantity sensor design incorporates a moving member with a first region of penetration holes and a second region without holes, optimizing hole size and arrangement to balance sensitivity and damping, thereby enhancing mechanical strength and vibration detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If penetration holes are formed in the moving member to reduce damping, then the sensitivity and vibration detection capability are improved, but the mechanical strength is reduced
Solution Approach 1:
The moving member is divided into different regions with different hole distributions: a first region with multiple penetration holes to reduce damping and improve sensitivity, and a second region without penetration holes to maintain mechanical strength and prevent damage during excessive acceleration. This local differentiation resolves the contradiction by optimizing each region for its specific function.
2Reliability
If the moving member is made more robust to withstand excessive acceleration, then the reliability is improved, but the damping increases and sensitivity decreases
Solution Approach 1:
Different regions of the moving member have different structural characteristics: the first region with penetration holes provides low damping for sensitive vibration detection, while the second region without holes provides high strength for reliable operation under excessive acceleration. This local quality differentiation allows the system to achieve both reliability and low damping simultaneously.
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 reduces damping and increases mechanical strength, allowing for accurate detection of vibrations and resistance to high-frequency vibrations without damage.
Implementation Method 1
a first region that has a plurality of penetration holes penetrating the moving member in the third direction... effectively reducing damping
Implementation Method 2
a fixed detection electrode arranged at the substrate and detecting an electrostatic capacitance generated between the moving member and the fixed detection electrode
Data Source
AI summary
A physical quantity sensor includes, when three directions orthogonal to one another are defined as a first direction, a second direction, and a third direction, a substrate; and a moving member facing the substrate in the third direction via a gap and becoming displaced in the third direction in relation to the substrate. The moving member has a first region that has a plurality of penetration holes penetrating the moving member in the third direction and having a square opening shape as viewed from the third direction, and a second region having no penetration hole. At least one of a length in the first direction and a length in the second direction of the second region is equal to or greater than S0+2×S1, where S0 is a length of one side of the penetration hole, and S1 is a space between the penetration holes next to each other.