Resilient Movable Body for MEMS Inertial Sensor Stiction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS inertial sensors face a sticking phenomenon due to excessive rotational displacement caused by intensive impacts, leading to stiction between the movable body and the limiter, which affects their accuracy and reliability.
Innovation Solution
Incorporating resilient portions with protrusions and through holes in the movable body, which deform upon collision to reduce impact and prevent stiction, while maintaining sensitivity by minimizing air resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the movable body is designed as a rigid body to maintain structural strength, then the strength is improved, but the sticking phenomenon occurs due to excessive rotational displacement during intensive impacts
Solution Approach 1:
The movable body incorporates a resilient portion that functions as a flexible element, allowing controlled deformation during impact events. This resilient portion absorbs impact energy through elastic deformation, preventing the excessive rotational displacement that causes the movable body to collide with and stick to the abutment, while maintaining overall structural integrity.
Solution Approach 2:
The resilient portion changes the mechanical parameters of the movable body by introducing compliance to specific regions. This allows the structure to dynamically adjust its stiffness characteristics during operation, remaining rigid under normal conditions but becoming flexible during intensive impacts to prevent stiction.
2Measurement precision
If the movable body is made larger to improve detection sensitivity, then the sensitivity is improved, but the air resistance increases which affects performance
Solution Approach 1:
The resilient portion includes through holes that create a porous structure. This porous design reduces the effective surface area exposed to air, thereby decreasing air resistance while maintaining the overall size and mass of the movable body needed for adequate detection sensitivity. The through holes allow air to pass through rather than creating excessive drag on the entire surface.
Solution Approach 2:
The movable body exhibits different structural qualities in different regions: the resilient portion with through holes provides reduced air resistance, while other portions maintain solid structure for sensitivity. This local differentiation optimizes both detection sensitivity and aerodynamic performance by placing each structural characteristic where it is most beneficial.
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 solution effectively suppresses stiction and enhances the impact resistance and sensitivity of the inertial sensors, improving their reliability and accuracy in detecting accelerations.
Implementation Method 1
the movable body includes a resilient portion in a portion opposed to the limiter... the resilient portion... deform upon collision to reduce impact
Implementation Method 2
a movable body which is fixed to the substrate, oscillates around an oscillation axis along the X axis... capable of detecting the acceleration in a vertical direction
Data Source
AI summary
An inertial sensor is an inertial sensor for detecting a physical quantity based on a displacement in a Z axis when defining three axes perpendicular to each other as an X axis, a Y axis, and the Z axis, and is provided with a substrate, a movable body which is fixed to the substrate, oscillates around an oscillation axis along the X axis, and has two planes opposed to each other and side surfaces connecting the two planes to each other, and a limiter which is fixed to the substrate, and is opposed to the side surfaces of the movable body, wherein the movable body is provided with a resilient portion in a portion opposed to the limiter.