Physical Quantity Sensor with Intermediary Shielder for Acceleration Detection
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Solution Overview
Problem
Existing acceleration sensors face issues with detection sensitivity due to electrostatic attractive forces between movable elements with different potentials, which interfere with the detection of acceleration.
Innovation Solution
A physical quantity sensor design featuring a shielder between movable bodies to maintain a constant electric field and prevent interference from Coulomb forces, allowing for accurate detection of accelerations by maintaining a balanced potential distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different potentials are applied to the two movable elements to detect acceleration, then detection capability is enabled, but electrostatic attractive force is generated between the movable elements which deteriorates detection sensitivity
Solution Approach 1:
A shielder is introduced as an intermediary component between the first and second movable elements. The shielder is electrically connected to a potential source and positioned to face both movable elements, creating an electric field that counteracts the electrostatic attractive force between the movable elements. This intermediary structure enables the application of different potentials to the movable elements for acceleration detection while eliminating the harmful electrostatic attraction through the mediating electric field from the shielder.
2Device complexity
If two separate electrodes are used for detection, then structural simplicity is maintained, but electrostatic interference between movable elements occurs
Solution Approach 1:
The shielder serves as an intermediary electric field source that resolves the conflict between using simple separate electrodes and maintaining detection accuracy. By positioning the shielder between the movable elements and applying appropriate potential, the system maintains the simplicity of separate fixed electrodes while the shielder's electric field prevents electrostatic interference, thereby preserving both structural simplicity and detection accuracy.
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 sensor achieves high accuracy in detecting accelerations by minimizing interference from Coulomb forces, ensuring precise measurement of physical quantities.
Implementation Method 1
an electrostatic attractive force is generated between the two movable elements, and the electrostatic attractive force may deteriorate detection sensitivity of the acceleration sensor
Implementation Method 2
minimizing interference from Coulomb forces
Data Source
AI summary
A physical quantity sensor includes: a substrate; a first anchor; a second anchor; a first support beam; a second support beam; a first movable body; a second movable body; and a shielder. A first fixed electrode and a second fixed electrode are provided on the substrate. The first movable body is provided to be swingable with respect to the substrate about a first rotation axis along a second direction. The second movable body is provided to be swingable with respect to the substrate about a second rotation axis along the second direction. The shielder is provided between the first movable body and the second movable body along a first direction.