Inertial Sensor Frame Structure for Z-Axis Displacement Control
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Solution Overview
Problem
Existing acceleration sensors face issues with excessive displacement and damage when subjected to acceleration in the Z-axis direction, leading to potential malfunction due to stress and sticking with the substrate.
Innovation Solution
The design incorporates a movable portion with a frame surrounding a fixed portion, featuring first and second outer edges and projection parts that reduce excessive displacement by distributing contact impact and minimizing contact areas, along with a spring mechanism and electrodes to stabilize the movable portion and prevent unintended displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the movable portion is designed to be displaceable with respect to the substrate, then the acceleration measurement function is improved, but the movable portion is excessively displaced in the Z axis direction causing damage or sticking
Solution Approach 1:
The frame part is designed with outer edges that protrude toward the substrate before excessive displacement occurs, creating a preliminary mechanical constraint that prevents the movable portion from displacing too far in the Z-axis direction, thus avoiding damage or sticking while preserving acceleration measurement capability
Solution Approach 2:
The frame part is segmented into multiple sides with outer edges at different positions, allowing selective contact with the substrate at specific locations to control displacement without completely restricting movement, maintaining measurement functionality while preventing excessive displacement
2Object-affected harmful factors
If the movable portion is displaced in the Z axis direction, then contact with the substrate is reduced, but excessive displacement causes stress damage or sticking
Solution Approach 1:
The frame part's outer edges are positioned to contact the substrate before excessive Z-axis displacement occurs, creating a preliminary mechanical stop that prevents both sticking and stress damage by limiting the maximum displacement distance
Solution Approach 2:
The outer edges of the frame part act as intermediary elements between the movable portion and the substrate, providing controlled contact points that mediate the interaction to prevent both sticking and excessive stress on the movable portion structure
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 damage to the sensor components, prevents sticking, and maintains accurate measurement of acceleration by minimizing excessive displacement and stress, thereby enhancing the mechanical strength and reliability of the acceleration sensor.
Implementation Method 1
a movable detection electrode provided at the movable portion, and a fixed detection electrode which is fixed to the substrate and forms an electrostatic capacitor with the movable detection electrode
Implementation Method 2
a spring mechanism and electrodes to stabilize the movable portion
Data Source
AI summary
A inertial sensor includes a substrate, a fixed portion that is fixed to the substrate, a movable portion is connected to the fixed portion, and is displaceable in an X axis direction, and a movable electrode that is supported at the movable portion, and a frame part includes a first edge that is located on one side of the X axis direction, and is disposed along a Y axis direction, and a second edge that is located on the other side of the X axis direction, and is disposed along the Y axis direction. The fixed portion is disposed further toward the second edge than the first edge, and the substrate includes a first projection that overlaps the first edge, and is disposed to be separated from the first edge, and a second projection that overlaps the second edge, and is disposed to be separated from the second edge.