Acceleration Sensor Mass Distribution and Impact Buffering
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Solution Overview
Problem
In reflection seismic surveys, existing acceleration sensors face challenges in achieving low noise and high sensitivity with high impact resistance, particularly in MEMS technology, due to limitations in mass distribution and impact buffering in both vertical and horizontal directions.
Innovation Solution
The acceleration sensor design incorporates a three-layer structure with different mass and length configurations for movable portions and a two-layer structure for the stopper portion, utilizing a silicon substrate to enhance mass distribution and impact resistance by adjusting the thickness and processing depth of layers to minimize the distance between the mass body and the stopper, thereby reducing impact force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mass of the movable portion is increased to achieve low noise and high sensitivity, then measurement precision is improved, but impact resistance deteriorates due to increased inertia and collision force
Solution Approach 1:
The movable portion is divided into multiple movable layers (first movable layer, second movable layer) with different masses and dimensions. This segmentation allows the system to achieve high sensitivity through appropriate mass distribution while reducing impact collision forces by distributing the mass across multiple smaller components rather than one large mass.
Solution Approach 2:
The stopper portion is designed with elastic properties (using elastic material or elastic structure) to provide cushioning before impact occurs. The elastic portion absorbs impact energy through deformation, preventing direct rigid collision between the movable portion and stopper, thereby protecting the high-mass movable portion from damage during impact events.
2Measurement precision
If the movable portion is made larger to increase mass, then sensitivity is improved, but the distance to the stopper increases, worsening impact resistance
Solution Approach 1:
The patent utilizes a three-dimensional layered structure where the movable portion and stopper are arranged in the vertical direction (thickness direction) rather than only in the horizontal plane. By controlling the thickness of the intermediate substrate and the vertical positioning of layers, the system achieves close proximity between the movable portion and stopper in the vertical dimension while maintaining adequate horizontal space for the movable portion's mass.
3Device complexity
If a single-layer structure is used for simplicity, then device complexity is reduced, but impact resistance is insufficient to prevent both ductile and brittle fractures
Solution Approach 1:
Both the movable portion and stopper portion are constructed with multiple layers (first layer and second layer) rather than single monolithic structures. This multi-layer segmentation provides redundancy and distributes stress during impact, preventing catastrophic failure through both ductile and brittle fracture modes that would occur in single-layer structures.
Solution Approach 2:
The patent employs composite structural design where different layers may have different material properties or thicknesses optimized for their specific functions. The intermediate substrate, movable layers, and elastic layers form a composite structure that combines the benefits of different materials to achieve both sensitivity and impact resistance.
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 allows for a larger mass in the movable portion with improved impact resistance, effectively preventing both ductile and brittle fractures during strong impacts, enhancing the sensor's performance in seismic surveys.
Implementation Method 1
the elastic portion is made of an elastic material or has an elastic structure, thereby having impact buffering capability
Implementation Method 2
a proof mass, a frame, and a spring that connects the proof mass and the frame
Data Source
AI summary
Provided is an acceleration sensor having a large mass in a movable portion, and realizing high impact resistance. An acceleration sensor element 10a includes an upper substrate 20, a lower substrate 21 spaced apart from the upper substrate 20, and an intermediate substrate 19 provided between the upper substrate 20 and the lower substrate 21. Each of a first movable portion 16, a second movable portion 17, a frame portion 12, a fixed portion 13, and a spring portion 14 constituting the intermediate substrate 19 is configured with two layers of an upper layer and a lower layer, and a stopper portion 18 is provided at one end of the frame portion 12. A distance 31 between an end portion of the first movable portion 16 or the second movable portion 17 and an end portion of the stopper portion 18 in the upper layer and a distance 32 between an end portion of the first movable portion 16 or the second movable portion 17 and an end portion of the stopper portion 18 in the lower layer are different from each other.