Acceleration Sensor Beam Support for Sensitivity
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Solution Overview
Problem
Existing acceleration sensors face reduced detection sensitivity due to the distribution of inertial force when the weight member is supported at multiple locations, leading to decreased displacement magnitude and resonance frequency changes, which complicates accurate acceleration detection.
Innovation Solution
An acceleration sensor design where the weight member is supported by a vibrating beam and a holding beam at two locations, preventing inertial force distribution and enhancing displacement magnitude, with a point-symmetric vibration mode and specific beam configurations to increase sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the weight member is supported at multiple locations, then the structural stability is improved, but the detection sensitivity is reduced due to distribution of inertial force
Solution Approach 1:
The support structure is segmented into multiple beams (first holding beam, second holding beam, first support beam, second support beam) that are spatially distributed. Each beam independently supports the weight member at specific locations, allowing the inertial force to be distributed across multiple segments rather than concentrated at a single point, thereby maintaining structural stability while enabling sensitive detection through controlled displacement of each segment.
Solution Approach 2:
The holding beams and support beams are configured with asymmetric dimensions and orientations relative to the acceleration detection direction. The first holding beam has different width and thickness dimensions compared to the second holding beam, and they are arranged at different orientations. This asymmetric configuration ensures that while the structure remains stable through multiple support points, the beams themselves exhibit sufficient displacement in the acceleration direction for sensitive detection, resolving the contradiction between stability and sensitivity.
2Measurement precision
If the weight member is supported at two locations by vibrating beam and holding beam, then the displacement magnitude is enhanced, but the structural complexity increases
Solution Approach 1:
The holding beams and support beams are merged into an integrated support structure that collectively supports the weight member at two primary locations. The first holding beam and first support beam form one support location, while the second holding beam and second support beam form the other location. This merging approach achieves the desired displacement magnitude through the coordinated action of multiple beams while avoiding the complexity of completely separate support systems, as the beams work together as a unified structure.
Solution Approach 2:
Each beam in the structure serves multiple functions: the holding beams provide both structural support and act as vibrating elements for detection, while the support beams simultaneously constrain the weight member's motion and contribute to the overall structural stability. This multi-functionality reduces the total number of components needed compared to a system with dedicated support elements and sensing elements, thereby achieving enhanced displacement magnitude without proportionally increasing structural complexity.
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
Significantly increased detection sensitivity for acceleration by maximizing displacement and resonance frequency changes, resulting in improved sensitivity and reduced influence from non-target axis directions.
Implementation Method 1
detect, in a state where a weight member is connected to a vibrating portion and the vibrating portion is vibrated at a resonant frequency of a natural vibration thereof, a magnitude of acceleration from a change in the resonant frequency of the natural vibration of the vibrating portion
Implementation Method 2
a piezoelectric layer 17; a lower electrode layer 18 provided on the piezoelectric layer 17; and an upper electrode layer 16 provided on the piezoelectric layer 17
Data Source
AI summary
A weight member includes two sides opposite to each other in an X-axis direction when looked at in a plan view. A vibrating beam includes one end portion connected at one location to a fixation member and the other end portion connected at one location to one of the two sides of the weight member in the X-axis direction when looked at in a plan view. The vibrating beam supports the weight member to be displaceable in the X-axis direction. A holding beam includes one end portion connected at one location to the fixation member and the other end portion connected at one location to the other of the two sides of the weight member opposing to each other in the X-axis direction when looked at in a plan view. The holding beam supports the weight member to be displaceable in the X-axis direction. A driver is disposed on the vibrating beam and vibrates the vibrating beam. A detector is disposed on the vibrating beam and configured to output a detection signal changes according to deformation of the vibrating beam.