Gas-Filled Pressure Sensor with Elastic Sealing and Mechanical Stop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gel-filled pressure sensors for measuring heart rate are prone to damage from excessive force and cyclical loads, and are sensitive to accelerative forces, leading to inaccurate measurements due to the mass of the gel and potential damage to electrical components.
Innovation Solution
A pressure sensor with a gas-filled housing and an elastic sealing element that includes a moveable arcuate portion or protrusion, which transmits pressure to a semiconductor die with a mechanical stop to prevent excessive motion and protect the die from damage, allowing for accurate heart rate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gel-filled housing is used for transmitting pressure waves, then pressure transmission and protection of electronic components are improved, but the sensor becomes sensitive to accelerative forces and prone to damage from excessive force and cyclical loads
Solution Approach 1:
The patent replaces the gel-filled housing with a gas-filled housing. Gas is used as the pressure transmission medium instead of gel. The gas-filled cavity transmits pressure waves to the diaphragm while having significantly reduced mass compared to gel, thereby minimizing sensitivity to accelerative forces while maintaining pressure transmission capability and protection of electronic components.
Solution Approach 2:
The patent changes the physical state and material properties of the pressure transmission medium from gel (viscoelastic solid) to gas (compressible fluid). This parameter change reduces the mass and inertia of the medium, eliminating sensitivity to accelerative forces while maintaining the ability to transmit pressure waves to the sensing diaphragm.
2Reliability
If gel is used as pressure transmission medium, then pressure wave transmission is achieved, but the gel is subject to damage from excessive force and cyclical loads
Solution Approach 1:
The patent uses gas instead of gel as the pressure transmission medium. Gas is inherently more resistant to damage from excessive force and cyclical loads because it is compressible and does not have the structural integrity issues that gel experiences. The gas-filled housing maintains pressure transmission while being durable under various loading conditions.
Solution Approach 2:
The patent changes the material from gel to gas, fundamentally altering the mechanical properties. Gas has negligible shear strength and is highly compressible, allowing it to withstand excessive force and cyclical loading without the damage mechanisms that affect gel, while still transmitting pressure changes to the diaphragm.
3Measurement precision
If elastic sealing element with moveable portion is used to transmit pressure, then measurement accuracy is improved, but the risk of damage to semiconductor die from excessive motion increases
Solution Approach 1:
The patent incorporates a mechanical stop between the moveable portion of the elastic sealing element and the semiconductor die. This stop acts as a pre-positioned protective element that limits the maximum travel of the moveable portion before it can contact the die. It cushions against excessive motion by providing a physical barrier, allowing full pressure transmission for accurate measurement while preventing damage to the die.
Solution Approach 2:
The mechanical stop serves as an intermediary element positioned between the elastic sealing element and the semiconductor die. It mediates the interaction by allowing normal pressure transmission during operation while blocking excessive motion that would otherwise directly contact and potentially damage the die. The stop translates the direct contact scenario into a protected, limited-motion scenario.
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 gas-filled housing with an elastic sealing element provides a more robust and accurate means of measuring heart rate by reducing the risk of damage from external forces and improving measurement precision by minimizing the impact of accelerative forces.
Implementation Method 1
a first housing defining a gas-filled interior cavity arranged on the substrate... a portion of the elastic sealing element is configured to be moveable in response to a pressure acting thereon
Implementation Method 2
an elastic sealing element is attached to the free end of the first housing... a portion of the elastic sealing element is configured to be moveable in response to a pressure acting thereon
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
A pressure sensor including a substrate having a first housing defining a gas- filled interior cavity arranged thereon. An elastic sealing element is attached to a free end of the first housing and generally covers an open end of the interior cavity for sealing the interior cavity with respect to an external environment. A portion of the elastic sealing element is configured to be moveable in response to a pressure acting thereon. A semiconductor die is arranged on the substrate and defines a pressure sensing diaphragm exposed to the gas occupying the interior cavity.