Physical Quantity Detection Device with Function Membrane for Stability
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Solution Overview
Problem
Existing absolute pressure sensors face challenges in reducing thickness while maintaining output stability, as output variations increase when the glass substrate thickness decreases below a certain value, making it difficult to achieve small and low-profile sensors like those needed for cellular phones.
Innovation Solution
A physical quantity detection device with a diaphragm part on a silicon substrate bonded to a glass substrate using anodic bonding, and a function membrane on the glass substrate to prevent alkali metal ion migration and moisture contact, which helps maintain output stability even with reduced glass substrate thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the glass substrate thickness is reduced to achieve smaller and lower-profile sensors, then the device size is reduced, but the output stability deteriorates due to increased output variations
Solution Approach 1:
A function membrane is introduced as an intermediary layer between the glass substrate and the external environment. This membrane prevents alkali metal ions from migrating out of the glass substrate when thickness is reduced, thereby maintaining output stability while enabling smaller device size. The membrane acts as a barrier that mediates the interaction between the reduced-thickness glass substrate and moisture in the atmosphere.
Solution Approach 2:
The sensor structure employs composite materials by combining the glass substrate with a function membrane having different material properties. This composite structure allows the glass substrate to be made thinner while the membrane compensates for the increased susceptibility to ion migration, thus resolving the contradiction between reduced size and maintained reliability.
2Length of stationary object
If the glass substrate thickness is reduced below a certain value, then the device becomes thinner, but the output variations increase making it difficult to meet specifications
Solution Approach 1:
The function membrane serves as a protective intermediary that allows the glass substrate thickness to be reduced while preventing excessive output variations. By blocking the migration path of alkali metal ions, the membrane enables thinner glass substrates to meet output precision specifications that would otherwise be unattainable.
Solution Approach 2:
The invention changes the physical-chemical parameters of the glass substrate system by adding a function membrane with specific barrier properties. This parameter change (introducing the membrane layer) allows the glass substrate thickness parameter to be reduced while maintaining output variation within acceptable limits.
3Device complexity
If no function membrane is used, then the device structure is simpler, but alkali metal ion migration occurs causing output instability
Solution Approach 1:
A function membrane is introduced as a protective intermediary layer between the glass substrate and the external environment. This membrane prevents alkali metal ions from migrating out of the glass substrate, thereby maintaining output stability while enabling smaller device size. The membrane acts as a barrier that mediates the interaction between the reduced-thickness glass substrate and moisture in the atmosphere.
Solution Approach 2:
The sensor structure employs composite materials by combining the glass substrate with a function membrane having different material properties. This composite structure allows the glass substrate to be made thinner while the membrane compensates for the increased susceptibility to ion migration, thus resolving the contradiction between reduced size and maintained reliability.
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 function membrane significantly reduces output variations, allowing the physical quantity detection device to meet acceptable specifications even when the glass substrate thickness is reduced, ensuring stable pressure detection in thinner sensor designs.
Implementation Method 1
a function membrane formed on a second surface of the glass substrate opposite to the first surface. The function membrane prevents the second surface of the glass substrate from coming into contact with moisture in the atmosphere
Implementation Method 2
a substrate including a physical quantity detection part and bonded to a first surface of the glass substrate with a hermetically sealed space being formed inside the substrate
Data Source
AI summary
A physical quantity detection device includes a glass substrate, a substrate including a physical quantity detection part and bonded to a first surface of the glass substrate with a hermetically sealed space being formed inside the substrate, and a function membrane formed on a second surface of the glass substrate opposite to the first surface. The function membrane prevents the second surface of the glass substrate from coming into contact with moisture in the atmosphere.