Physical Quantity Sensor Shielding for Noise Isolation
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Solution Overview
Problem
Existing physical quantity sensors face issues with noise interference between angular velocity and acceleration detection elements, leading to deteriorated detection accuracy due to mixed signals.
Innovation Solution
The implementation of a physical quantity sensor configuration that includes an angular velocity detection element, an acceleration detection element, and a shield unit connected to a fixed potential, with the shield unit strategically placed between the elements and signal wirings to minimize noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the angular velocity detection element and acceleration detection element are accommodated in layers in a package, then the device integration is improved, but noise interference occurs between the elements
Solution Approach 1:
A shield unit is introduced as an intermediary component between the angular velocity detection element and the acceleration detection element. The shield unit includes a shield electrode that is electrically connected to a reference potential, creating an electrostatic barrier that blocks noise interference while allowing the elements to remain in close proximity for integrated operation.
Solution Approach 2:
The internal space of the package is divided into multiple regions using the shield unit, which physically and electrically segments the space between the angular velocity detection element and the acceleration detection element. This segmentation allows each element to operate in its own designated zone with reduced mutual interference.
2Area of stationary object
If the drive signal wiring and detection signal wiring are placed in close proximity, then the device area is reduced, but signal noise increases
Solution Approach 1:
The shield unit with the shield electrode acts as an intermediary barrier between the drive signal wiring and detection signal wiring. By connecting the shield electrode to a reference potential, it creates an electrostatic shield that prevents coupling noise from the high-amplitude drive signals from interfering with the low-level detection signals, even when the wirings are placed in close proximity.
3Object-affected harmful factors
If the shield unit is added between detection elements, then noise interference is reduced, but device complexity increases
Solution Approach 1:
The shield unit serves multiple functions simultaneously: it acts as an electrostatic barrier to block noise interference, provides physical separation between detection elements, and can be integrated with existing package structures. The shield electrode is electrically connected to a reference potential, and this multi-functional design reduces the need for additional separate components.
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 configuration effectively reduces noise and enhances detection accuracy by isolating signal interference, allowing for precise measurement of both angular velocity and acceleration.
Implementation Method 1
a shield unit that is located between the angular velocity detection element and the acceleration detection signal wiring and is connected to a fixed potential
Data Source
AI summary
A physical quantity sensor includes: an angular velocity detection element; an acceleration detection element; a bonding wire through which a detection signal of the acceleration detection element propagates; and a shield unit that is located between the angular velocity detection element and the bonding wire and is connected to a fixed potential. The angular velocity detection element and the acceleration detection element are disposed to be deviated in a height direction. At least a part of the shield unit is disposed between the angular velocity detection element and the acceleration detection element.