Bossed Diaphragm Cross Pattern for Pressure Sensor Sensitivity
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Solution Overview
Problem
Existing pressure sensors with flat plate diaphragms lack sensitivity and linearity at low pressures and have lower burst pressure ratings due to sharp edges and corners, which contribute to high stress points and non-linear responses.
Innovation Solution
A pressure sensor design featuring a bossed diaphragm with a simple cross pattern, where the edges and corners are rounded to reduce stress points and increase burst pressure, combined with a low noise amplifier for improved sensitivity and linearity, is used. The bossed diaphragm is fabricated using a silicon substrate and epitaxial layer with a patterned buried layer and epitaxial layer, and the amplifier is integrated on the same sensor die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat plate diaphragm is used, then the manufacturing is simple, but the sensitivity and linearity at low pressures are insufficient
Solution Approach 1:
The patent applies curvature by introducing a boss (protruding structure) on the diaphragm surface instead of using a flat plate. This curved/raised structure increases the mechanical leverage and deflection at low pressures, thereby improving sensitivity and linearity while maintaining manufacturability through standard MEMS fabrication processes
2Measurement precision
If a bossed diaphragm with sharp edges and corners is used, then the sensitivity is improved, but the burst pressure rating decreases due to high stress points
Solution Approach 1:
The patent applies curvature by rounding the edges and corners of the boss structure. This eliminates sharp geometric discontinuities that act as stress concentration points, thereby preventing premature failure and increasing the burst pressure rating while maintaining the sensitivity benefits of the bossed design
3Measurement precision
If a bossed diaphragm with intricate pattern is used, then the sensitivity is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by using a simple cross-pattern boss design rather than an intricate pattern. This localized structural feature provides sufficient sensitivity improvement through its geometric configuration while avoiding the manufacturing complexity and potential non-linearity issues associated with overly complex patterns
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 bossed diaphragm with a cross pattern provides 50% to 100% more sensitivity and a more linear pressure response with reduced orientation sensitivity and a lower total error band, while the rounded edges increase the burst pressure rating, resulting in a more effective and reliable pressure sensor.
Implementation Method 1
Piezoresistors may be located in or on the diaphragm portion to measure deflection of the diaphragm to form a pressure transducer
Implementation Method 2
The diaphragm may deflect according to a magnitude of the pressure on one side of the diaphragm that exceeds a pressure on an opposite surface of the diaphragm
Data Source
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AI summary
A pressure sensor having a diaphragm having a boss with a pattern. The diaphragm having a boss may be regarded as a bossed diaphragm. The bossed diaphragm may have higher sensitivity than a flat plate diaphragm having the same area as the bossed diaphragm. The bossed diaphragm may incorporate a simple cross pattern that can further improve the sensitivity and linearity of a pressure response of the diaphragm at low pressures. Reduction of sharp edges and corners of the boss and its legs around the periphery of the diaphragm may reduce high stress points and thus increase the burst pressure rating of the bossed diaphragm.