Heater Module With Trimmable Resistor for Thermal Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thick-film heating elements with ceramic substrates face challenges in integrating temperature sensors due to incompatibility with co-firing processes, leading to manufacturing tolerances that are too large for thermal protection and EMC requirements.
Innovation Solution
A heater module is created with a thermally coupled temperature sensor and a trimmable resistor, allowing for precise resistance adjustment through trimming techniques, which can be embedded in the substrate or connected via vias, to achieve precise resistance values for thermal protection applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensors are integrated into ceramic substrate heating elements, then thermal protection function is achieved, but manufacturing precision deteriorates due to incompatibility with co-firing processes
Solution Approach 1:
The heating element is divided into separate functional modules: a ceramic heating element and a separate temperature sensor assembly. This segmentation allows each component to be manufactured using optimized processes - the ceramic element via co-firing and the temperature sensor with precise resistance values via separate precision manufacturing, then assembled together. This resolves the contradiction by eliminating the incompatibility between sensor integration and co-firing precision requirements.
Solution Approach 2:
A trimmable resistor is introduced as an intermediary component between the temperature sensor and the heating element circuit. This trimmable resistor allows for post-manufacturing adjustment of the overall resistance value, compensating for tolerances in the temperature sensor and achieving the required precision without requiring the sensor itself to be manufactured with tight tolerances during co-firing.
2Ease of manufacture
If standard manufacturing tolerances are used for temperature sensors, then manufacturing complexity is reduced, but reliability deteriorates due to insufficient precision for thermal protection
Solution Approach 1:
The temperature sensor is pre-manufactured with standard tolerances using simple processes, and then a trimmable resistor is added in series to adjust the combined resistance to the precise value required for thermal protection. This preliminary manufacturing approach maintains ease of manufacture while achieving the reliability needed for thermal protection through the subsequent trimming adjustment.
Solution Approach 2:
The resistance value of the temperature sensing circuit is made adjustable through the trimmable resistor, which can be trimmed to change its resistance value. This parameter adjustment capability allows the system to achieve the precise resistance value required for reliable thermal protection, even when the base temperature sensor is manufactured with standard tolerances, thus maintaining ease of manufacture while improving reliability.
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 solution enables precise control of the temperature sensor or heater performance, reducing manufacturing tolerance errors and ensuring compliance with regulatory standards for thermal protection, while maintaining thermal compatibility and reducing manufacturing complexity.
Implementation Method 1
The heating film 16 is configured to produce heat by the Joule effect on conducting an electrical current
Implementation Method 2
a temperature sensor thermally coupled to the heater
Data Source
AI summary
A heater module includes a heater assembly including a heater and a temperature sensor thermally coupled to the heater, and a trimmable resistor electrically coupled to the temperature sensor or to the heater.