Mesh Heater Layout in Thermal Sensor Chips for Low-Resistance Gas Sensing
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Solution Overview
Problem
Conventional thermal gas sensors face reduced detection sensitivity due to increased resistance and difficulty in heating element temperature increase, which hampers heat dissipation performance.
Innovation Solution
A thermal sensor chip with a substrate having a cavity and a membrane-covered heater in a mesh form, utilizing monocrystalline silicon and an insulating thin film membrane, allows for efficient heat dissipation by reducing resistance and increasing the contact area with the gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the heating element is arranged to meander to improve heat dissipation performance, then the heat dissipation area increases, but the resistance value increases and the temperature of the heating element becomes difficult to increase
Solution Approach 1:
The heating element transitions from a one-dimensional meandering path to a two-dimensional mesh structure. This dimensional change allows the heater to cover a larger area without proportionally increasing the path length, thereby improving heat dissipation performance while controlling resistance and maintaining detection sensitivity.
Solution Approach 2:
The heating element is divided into multiple wire segments arranged in a mesh pattern. This segmentation creates multiple parallel heat dissipation paths, increasing the effective heating area while distributing the electrical resistance across multiple parallel conductors, thus reducing overall resistance compared to a single meandering path.
2Area of stationary object
If the heating element is arranged to meander to increase the length, then the heat dissipation area increases, but the resistance value increases
Solution Approach 1:
The heater adopts a two-dimensional mesh configuration instead of a one-dimensional meandering layout. This allows achieving larger heater area with shorter total wire length, as the mesh structure utilizes spatial distribution more efficiently, reducing the cumulative path length and thus the resistance value.
Solution Approach 2:
Multiple wire segments in the mesh structure function as parallel electrical conductors. By merging these parallel paths, the overall resistance is reduced while maintaining a large effective heating area, as the current distributes across multiple parallel channels rather than following a single long path.
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 thermal sensor chip achieves improved heat dissipation performance, enhanced detection sensitivity, and reduced power consumption by utilizing a mesh-formed heater with increased area and lower resistance, stabilizing heat dissipation and reducing individual chip variations.
Implementation Method 1
a heater provided on or inside the membrane, wherein the heater includes wires in a mesh form constituted by a conductive member
Implementation Method 2
a membrane provided on a surface of the substrate so as to cover the opening
Implementation Method 3
a thermal gas sensor that uses a difference in temperature characteristics of thermal conductivity of gas
Data Source
AI summary
The thermal sensor chip includes a substrate in which a cavity having an opening is formed, a membrane provided on a surface of the substrate so as to cover the opening, and a heater provided on or inside the membrane, wherein the heater includes wires in a mesh form constituted by a conductive member.