Pressure Sensor Shielding Structure for Electric Field Isolation
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Solution Overview
Problem
Existing pressure sensors face challenges in reducing the effect of electric fields between the sensor chip and metallic diaphragm without increasing the number of components or assembly operations.
Innovation Solution
Incorporating an electric field blocking member, such as a conductive or insulating shielding plate, between the sensor chip and diaphragm, which is set to the same electric potential as the sensor chip, to block unwanted electric fields and prevent potential differences from affecting the electronic circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic lower plate and metallic member are added to surround the sensor chip and define a cylindrical space, then the electric potential difference between the metallic diaphragm and sensor chip is eliminated, but the number of components and assembly operation processes increases
Solution Approach 1:
The patent merges the shielding function with the existing hermetic glass structure by forming a recess in the hermetic glass that directly accommodates the sensor chip, eliminating the need for separate metallic shielding components. The hermetic glass itself serves as the shielding structure, combining sealing and shielding functions into a single component.
Solution Approach 2:
The hermetic glass is given multiple functions: it provides hermetic sealing for the sensor chip and simultaneously serves as the shielding structure to eliminate electric potential differences. This multi-functional design replaces what would traditionally require separate components for sealing and shielding.
2Reliability
If a presser plate is added to connect lead pins to zero potential, then electric field effects are reduced, but the number of assembly operation processes increases
Solution Approach 1:
The patent combines the lead pin connection function with the hermetic glass structure by forming a recess that directly receives and secures the lead pins. This integration eliminates the need for separate presser plates and simplifies the assembly process while maintaining electric field blocking capability.
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 the impact of electric fields on the sensor chip's electronic circuit without adding components or complicating the assembly process, ensuring accurate pressure detection.
Implementation Method 1
Incorporating an electric field blocking member, such as a conductive or insulating shielding plate, between the sensor chip and diaphragm, which is set to the same electric potential as the sensor chip, to block unwanted electric fields
Data Source
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AI summary
In a pressure sensor, a cap-shaped shielding member (17) to block an electric field undesirable for a signal processing electronic circuit unit of a sensor chip (16) is supported by an end surface of a disk conductive plate (19) between one end surface of the sensor chip (16) in a liquid sealing chamber (13) and a diaphragm (32). The conductive plate (19) is electrically connected via a group of input-output terminals (40ai) and bonding wires (Wi), for example, and the sensor chip 16 is supported by one end portion of a chip mounting member (18) which is electrically connected via the group of input and output terminals (40ai) and the bonding wires (Wi).