Pressure Sensor Diaphragm Stress Management
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Solution Overview
Problem
Existing pressure sensor chips face stress concentration and reduced withstand pressure due to direct bonding of stopper members to the sensor diaphragm, leading to potential breakage and manufacturing errors affecting performance.
Innovation Solution
A pressure sensor chip design featuring a sensor diaphragm with first and second holding members that include non-bonding regions and protrusions, allowing for pressure introduction holes and reducing stress concentration by distributing pressure evenly and preventing edge openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stopper members are directly bonded to the sensor diaphragm to prevent excessive displacement, then the sensor diaphragm is protected from breakage, but stress concentration occurs at the diaphragm edge and withstand pressure is reduced
Solution Approach 1:
The stopper member is segmented into a bonding region and a non-bonding region. The bonding region (with protrusions) is bonded to the sensor diaphragm to provide structural support and prevent excessive displacement, while the non-bonding region (recess) is left unbonded to avoid stress concentration at the diaphragm edge, thus resolving the contradiction between protection and strength
Solution Approach 2:
Different regions of the stopper member are given different bonding properties: the peripheral portion (bonding region) is bonded to provide support, while the central region (non-bonding region) is left unbonded to reduce stress concentration. This local differentiation allows the structure to simultaneously achieve protection and maintain high withstand pressure
2Stability of the object's composition
If the sensor diaphragm is restrained at the edge to prevent opening, then structural stability is improved, but stress concentration occurs and reduces measurement precision
Solution Approach 1:
The stopper member is divided into bonding and non-bonding regions, allowing the diaphragm to be restrained at the periphery (providing stability) while leaving the central measurement area free from bonding-induced stress (maintaining precision)
Solution Approach 2:
The non-bonding region acts as an intermediary zone that transmits pressure from the diaphragm to the stopper member structure without creating stress concentration, thereby maintaining both stability and measurement precision
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 design reduces stress concentration at the diaphragm edge, enhances withstand pressure, and facilitates easy enclosure of pressure transmitting media, ensuring reliable operation under varying pressures.
Implementation Method 1
Pressure transmitting media 9a and 9b, such as silicone oil, are enclosed in channels 8a and 8b that connect the pressure sensor chip 1 to the barrier diaphragms 5a and 5b
Implementation Method 2
Strain of the sensor diaphragm is detected as, for example, a change in resistance of a strain resistance gauge
Data Source
AI summary
A pressure sensor chip according to the present invention includes a non-bonding region that is provided in a stopper member and connected to a periphery of a pressure introduction hole. A plurality of protrusions are discretely formed on at least one of a first surface and a second surface that face each other in the non-bonding region. Passages between the protrusions serve as channels between the periphery of the pressure introduction hole and a peripheral edge of the non-bonding region. Accordingly, stress concentration does not occur at a diaphragm edge and the expected withstand pressure can be obtained.