Sensor Element Thermal Decoupling Plastic Housing
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Solution Overview
Problem
Existing sensor elements with plastic housings are unable to accommodate measuring elements that generate high heat, as they lack effective thermal decoupling and are limited by temperature resistance.
Innovation Solution
A sensor element design featuring a ceramic hotplate with thermal decoupling from the carrier substrate, integrated into a plastic molded housing, allowing for high media and temperature resistance while enabling direct encapsulation of electronic components and adjustable thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic molded housing is used to accommodate the measuring element, then media resistance and temperature resistance are improved, but the ability to accommodate high-heat generating measuring elements is lost
Solution Approach 1:
The housing is divided into two distinct parts: a plastic molded housing for structural support and media sealing, and a separate ceramic hotplate for thermal management. This segmentation allows each material to perform its optimal function - plastic provides chemical resistance and low thermal expansion, while ceramic provides thermal decoupling for high-heat elements.
Solution Approach 2:
The invention combines two different materials (plastic and ceramic) into a composite structure. The plastic molded housing integrates with a ceramic hotplate carrier substrate, creating a hybrid assembly that leverages the advantages of both materials - the chemical and dimensional stability of plastic plus the thermal properties of ceramic.
2Ease of manufacture
If the measuring element is directly molded into the plastic housing, then manufacturing simplicity is improved, but thermal decoupling of hot measuring elements is lost
Solution Approach 1:
The measuring element is not directly molded into the plastic housing but is instead mounted on a separate ceramic hotplate carrier substrate. This segmentation creates a thermal barrier between the hot measuring element and the plastic housing, while the carrier substrate provides a structured platform for integration.
Solution Approach 2:
The ceramic hotplate carrier substrate acts as an intermediary between the measuring element and the plastic housing. It provides thermal decoupling while still enabling mechanical support and electrical connections, thus mediating between the conflicting requirements of thermal isolation and structural integration.
3Temperature
If a metal housing is used for high-heat measuring elements, then thermal management is improved, but media resistance and thermal expansion control are worsened
Solution Approach 1:
The invention uses a composite structure combining plastic and ceramic materials to achieve both thermal management and chemical resistance. The ceramic hotplate provides thermal stability and decoupling, while the plastic housing provides chemical resistance and low thermal expansion, eliminating the need for metal housings.
Solution Approach 2:
Different parts of the housing have different material properties optimized for their specific functions. The ceramic hotplate area provides thermal management properties, while the plastic housing areas provide chemical resistance and dimensional stability. This local differentiation of material qualities allows simultaneous optimization of conflicting properties.
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
Enables the integration of hot measuring elements into plastic housings with enhanced thermal decoupling, media resistance, and low thermal expansion, facilitating the integration of additional features like heating devices and evaluation devices within a standard housing format.
Implementation Method 1
a heating device for actively heating the measuring surface
Implementation Method 2
the hotplate, which is made of ceramic in particular, with the corresponding carrier substrate. The contact/bond points and the associated connection circuitry are accommodated by the plastic molded housing. The carrier substrate with the contact/bond points and the corresponding connection circuitry are therefore molded into the plastic compound of the molded housing. The hotplate is not molded in, so that the thermal decoupling of the measuring element (the hotplate) from the carrier substrate or the corresponding contact/bonding points is ensured.
Data Source
Figure 1~2
AI summary
A sensor element may include a measuring element and a functional housing at least partially surrounding the measuring element including a plastic molded housing. The measuring element may include a hot plate mounted on a carrier substrate by means of narrow arms in a broadly thermally decoupled manner. The carrier substrate may be provided with contacts leading to the measuring element and terminating in contact/bonding points on the carrier substrate. The carrier substrate together with the contact/bonding points may be at least partially integrated into the plastic molded housing, leaving the hot plate exposed. The housing may include connection wiring for the contact/bonding points.