MEMS Gas Sensor Shielding Layer Heat Retention
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Solution Overview
Problem
MEMS gas sensors face high power consumption due to heat dissipation issues, which affects their efficiency and mechanical stability.
Innovation Solution
A MEMS gas sensor design incorporating a shielding layer that reduces heat transfer by convection and radiation, using materials with low absorptance and emissivity, and featuring ventilation holes to optimize sensor speed and power consumption, while providing mechanical support for thinner membranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gas sensitive element is heated to working temperature for gas detection, then the sensor can detect gas molecules, but heat dissipates to the environment causing high power consumption
Solution Approach 1:
The patent converts the harmful heat loss to the environment into a beneficial effect by using the shielding layer to reflect infrared radiation back to the gas sensitive element. The heat that would otherwise be wasted is now reused to maintain the working temperature, thereby reducing power consumption while preserving gas detection capability
Solution Approach 2:
The shielding layer acts as an intermediary between the gas sensitive element and the environment. It selectively reflects infrared radiation back to the element while allowing gas molecules to pass through via ventilation holes, thus mediating between heat retention and gas detection requirements
2Speed
If the membrane is made thinner to reduce heat capacity and improve response time, then the sensor responds faster to gas changes, but mechanical stability decreases
Solution Approach 1:
The patent segments the mechanical support function from the membrane by introducing a separate shielding layer structure. This allows the membrane to be thin for fast response while the shielding layer provides the necessary mechanical stability, dividing the structural support role from the sensing element
Solution Approach 2:
The patent creates a composite structure combining the thin membrane with the shielding layer that has both reflective and mechanical properties. This composite approach allows the system to achieve both fast thermal response (thin membrane) and mechanical stability (shielding layer support structure)
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 shielding layer significantly reduces power consumption by minimizing heat loss and enhances mechanical stability, allowing for thinner membranes and adjustable sensor performance.
Implementation Method 1
the shielding layer may be configured to partially reflect infrared electromagnetic radiation emitted by the gas sensitive element
Implementation Method 2
the shielding layer may be configured to reduce a heat transfer by convection and radiation
Implementation Method 3
the shielding layer may be configured to reduce a heat transfer by convection and radiation
Implementation Method 4
The shielding layer may also be configured to emit heat into the recess in response to being heated up by the heat from the gas sensitive element
Data Source
AI summary
A MEMS gas sensor is disclosed. In an embodiment a MEMS gas sensor includes a carrier having a recess, a gas sensitive element arranged in the recess and a shielding layer at least partially covering the recess.