Liquid-Sealed Cantilever Sensor for High-Sensitivity Pressure Detection
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Solution Overview
Problem
Conventional pressure sensors lack the sensitivity to detect pressure, sound pressure, acceleration, and gas with high precision, as they often rely on diaphragm structures that are limited by air flow and relative pressure measurements.
Innovation Solution
A pressure-sensitive sensor design featuring a cantilever with a sealed gas chamber, where the gap between the cantilever and frame is sealed by a liquid, allowing for indirect or direct pressure transmission through the liquid, enhancing sensitivity and accuracy by maintaining a hermetically closed state and using a detecting layer to measure deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diaphragm structure is used for pressure detection, then the sensor can measure pressure, but the sensitivity is limited due to air flow and relative pressure measurements
Solution Approach 1:
The patent introduces a liquid as an intermediary substance filling the gap between the cantilever and frame. This liquid mediator transmits external pressure to the cantilever while preventing air flow, thereby eliminating the limitations of direct air-based pressure transmission and enabling more sensitive and stable pressure detection
Solution Approach 2:
The patent transitions from air-based pressure transmission to liquid-based pressure transmission by filling the gap with liquid. This hydraulic approach allows for better pressure transmission characteristics, reduced compressibility effects, and improved measurement stability compared to pneumatic systems
2Measurement precision
If the gap around the cantilever is open to allow air flow, then pressure balance can be achieved, but liquid leakage may occur and sensitivity is reduced
Solution Approach 1:
The liquid filling the gap serves as a controlled intermediary that replaces uncontrolled air flow. It provides a seal that prevents leakage while maintaining pressure transmission, eliminating the harmful effects of both air flow interference and liquid leakage
Solution Approach 2:
The liquid creates an inert environment within the gap, preventing unwanted interactions between air and the sensing mechanism. This inert liquid medium eliminates air flow effects and prevents contamination or leakage issues
3Measurement precision
If a hermetically sealed gas chamber is formed by filling the gap with liquid, then sensitivity to absolute pressure and sound pressure is enhanced, but the device complexity increases
Solution Approach 1:
The liquid in the gap automatically forms a hermetic seal through capillary action and surface tension, creating a self-sealing gas chamber without requiring additional sealing components. This self-service mechanism achieves hermetic sealing while maintaining structural simplicity
Solution Approach 2:
The liquid acts as a flexible sealing medium that conformally fills the gap between the cantilever and frame, creating a hermetic seal that adapts to dimensional changes and thermal expansion without requiring rigid sealing structures
4Measurement precision
If the cantilever is used to detect deformation through piezoresistance, then high sensitivity is achieved, but the cantilever may be damaged by excessive external forces
Solution Approach 1:
The liquid filling the gap provides cushioning protection to the cantilever by absorbing and distributing excessive external forces before they can damage the cantilever. This prior cushioning mechanism protects the sensitive sensing element while maintaining measurement 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
The sensor achieves high sensitivity in detecting absolute pressure, sound pressure, and gas presence by minimizing reactive forces and leaks, enabling precise measurement of external forces and vibrations.
Implementation Method 1
a liquid which seals the gap
Implementation Method 2
The cantilever is manufactured so as to exert a piezoresistive effect
Implementation Method 3
the outside pressure is exerted on the cantilever indirectly through the liquid
Data Source
AI summary
The present invention achieves a pressure-sensitive sensor which can detect information on a pressure, a sound pressure, acceleration, gas and the like, with high sensitivity. The pressure-sensitive sensor includes: a cantilever (22); a frame (23) which is provided around the cantilever (22) and holds a base end of the cantilever (22); a gap (24) formed between the cantilever (22) and the frame (23); and a liquid (28) which seals the gap (24).