Planar MEMS Acceleration Sensor for Multi-Axis Measurement
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Solution Overview
Problem
Conventional acceleration sensors, particularly of the MEMS type, face challenges in constructing delicate structures in vertical directions, leading to assembly errors and vulnerability to impact or vibration when measuring both horizontal and vertical movements with high precision.
Innovation Solution
The acceleration sensor features a moving electrode with interconnected planar patterns, including frame, anchor, spring, and wing patterns, allowing for capacitance-based measurement in multiple directions, and a manufacturing method that uses a single mask to pattern a planar electrode layer, simplifying production and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a MEMS type acceleration sensor vertically transfers a structure to be cut out in a vertical direction, then the manufacturing process is simplified, but it is difficult to construct a delicate structure in the vertical direction
Solution Approach 1:
The patent transitions from vertical structure construction to planar structure construction by designing the movable electrode and opposing electrode to extend in horizontal directions (first and second directions) rather than vertically. This dimensional change allows delicate structures to be constructed in the planar direction where precision is easier to achieve, while still enabling vertical acceleration measurement through the planar electrode arrangement.
2Ease of manufacture
If the acceleration sensor is vertically mounted to measure movement of the vertical direction, then assembly is simplified, but an error may be generated in an assembly process and the structure may be weak against impact or vibration
Solution Approach 1:
The patent designs the sensor to measure vertical acceleration through a planar electrode configuration rather than vertical mounting. The movable electrode and opposing electrode are arranged in horizontal planes with spring patterns providing vertical restoring force, allowing the sensor to measure vertical acceleration while maintaining a robust planar structure resistant to impact and vibration.
Solution Approach 2:
The patent changes the measurement parameter from direct vertical displacement of vertically-mounted structures to capacitance change caused by vertical acceleration. The spring patterns provide a vertical restoring force that converts vertical acceleration into measurable capacitance variations, enabling vertical acceleration measurement with a horizontally-oriented robust structure.
3Ease of manufacture
If conventional MEMS processes are used for manufacturing, then production is simplified, but high precision measurement in both horizontal and vertical directions cannot be achieved
Solution Approach 1:
The patent designs a single planar electrode structure that can measure acceleration in multiple directions (horizontal and vertical) simultaneously. The movable electrode with spring patterns in multiple directions and opposing electrodes arranged to detect capacitance changes in different orientations enables multi-axis acceleration measurement using the same manufacturing process, achieving multi-functionality without requiring complex multi-directional fabrication.
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 design enables accurate measurement of acceleration in both horizontal and vertical directions while being robust against impact and vibration, with a simplified manufacturing process that reduces production costs and enhances structural stability.
Implementation Method 1
an opposing electrode forming a capacitance with the moving electrode, wherein the plurality of planar patterns include: a first frame pattern; a first anchor pattern fixing the moving electrode to a surrounding structure; a first spring pattern connecting the first frame pattern and the first anchor pattern and having a stretching direction of the first direction; a second spring pattern connecting the first frame pattern and the first anchor pattern and having a stretching direction of the second direction; a wing pattern; and a third spring pattern connecting the first frame pattern and the wing pattern and having a stretching direction of a third direction perpendicular to the first and second directions, and acceleration is measured depending on a change of the capacitance
Data Source
AI summary
An acceleration sensor includes: a moving electrode extending in at least one of a first direction and a second direction perpendicular to the first direction, and including a plurality of planar patterns connected with each other; and an opposing electrode forming a capacitance with the moving electrode, wherein the plurality of planar patterns include: a first frame pattern; a first anchor pattern fixing the moving electrode to a surrounding structure; a first spring pattern connecting the first frame pattern and the first anchor pattern and having a stretching direction of the first direction; a second spring pattern connecting the first frame pattern and the first anchor pattern and having a stretching direction of the second direction; a wing pattern; and a third spring pattern connecting the first frame pattern and the wing pattern and having a stretching direction of a third direction perpendicular to the first and second directions.