Physical Quantity Sensor Asymmetric Electrode Torque Wiring
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Solution Overview
Problem
Existing physical quantity sensors, such as those described in JP-A-2021-032819, face challenges in optimizing their structure for reduced size and increased sensitivity while accommodating wiring arrangements for capacitance detection, particularly in arranging wiring for movable and stationary electrodes.
Innovation Solution
A physical quantity sensor design that includes a substrate, a movable body with a support beam, stationary electrodes, and a wiring system where the rotary torque of the second movable electrode unit is lower than that of the first movable electrode unit, allowing for a bias in weight balance and optimized size, with the wiring extracted through an opening to enhance design freedom and reduce rotary torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiring is arranged to connect movable electrodes and stationary electrodes for capacitance detection, then the sensor can function properly, but the structural optimization for reduced size and increased sensitivity is hindered
Solution Approach 1:
The stationary electrode fixation part integrates both electrode fixation functionality and wiring extraction functionality. The wiring is extracted through the same fixation part that anchors the stationary electrode to the substrate, merging two functions into one structural element and reducing overall device complexity
Solution Approach 2:
The stationary electrode fixation part serves multiple purposes: it fixes the stationary electrode to the substrate, provides a pathway for wiring extraction through openings, and contributes to reducing rotary torque. This multi-functional design reduces the number of separate components needed
2Volume of moving object
If the sensor structure is optimized for reduced size, then miniaturization is achieved, but sensitivity may be compromised
Solution Approach 1:
The design optimizes the rotary torque parameters of the movable electrode units. By making the rotary torque of the second movable electrode unit lower than that of the first, the system achieves enhanced sensitivity while maintaining a compact structure. The asymmetric torque design allows for better detection precision within a reduced volume
3Ease of manufacture
If symmetric electrode units are used, then manufacturing is simplified, but rotary torque balance and sensitivity optimization are limited
Solution Approach 1:
The movable electrode units are designed with asymmetric rotary torque characteristics. The first movable electrode unit has a higher rotary torque than the second movable electrode unit, creating an intentional imbalance that optimizes detection sensitivity. This asymmetric design allows for enhanced measurement precision while still using standardized manufacturing processes for the electrode structures themselves
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 detection of physical quantities like acceleration with improved sensitivity and reduced size, while also allowing for increased design flexibility in wiring and structural optimization, minimizing the influence of substrate warpage.
Implementation Method 1
a first wiring line coupled to the first stationary electrode fixation part, wherein the movable body includes a first movable electrode unit having a movable electrode opposed to a stationary electrode of the first stationary electrode unit, and a second movable electrode unit having a movable electrode opposed to a stationary electrode of the second stationary electrode unit
Data Source
AI summary
The physical quantity sensor includes, a first support beam, a movable body, a first stationary electrode fixation part, a first stationary electrode unit, a second stationary electrode unit, and a first wiring line. The first stationary electrode unit is disposed at the first direction side of the first support beam and the second stationary electrode unit is disposed at a fourth direction side of the first support beam. A rotary torque of the second movable electrode unit is lower than a rotary torque of the first movable electrode unit. The movable body has an opening at a fourth direction side with respect to the first support beam, and the first wiring line is extracted from the first stationary electrode fixation part to an outside of the movable body through the opening.