Optical Waveguide Temperature Sensing for Isolated PCB Assemblies
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Solution Overview
Problem
Existing temperature measurement methods in electronic assemblies, particularly in power modules, suffer from high thermal resistance and complex galvanic isolation issues, leading to inaccurate and unsafe temperature estimation, which can cause irreparable damage and safety hazards.
Innovation Solution
A temperature measuring device using an optical waveguide with a microgrid structure integrated into a substrate material, allowing for direct, accurate, and fast temperature monitoring near the chip, utilizing optical sensors for reliable temperature measurement without electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chip-level temperature monitoring is implemented using conventional sensors (NTC, KTY, PT1000), then temperature measurement capability is provided, but galvanic isolation complexity increases and measurement reliability decreases due to electrical connection requirements in high-voltage environments
Solution Approach 1:
The patent replaces electrical sensing mechanisms with optical sensing. An optical waveguide with a microgrid structure is used to measure temperature through optical properties (refractive index changes) rather than electrical resistance changes. This substitution eliminates the need for galvanic isolation since optical signals are immune to electromagnetic interference and do not require electrical connections to the high-voltage power semiconductor.
Solution Approach 2:
The optical waveguide acts as an intermediary between the temperature measurement function and the high-voltage environment. The waveguide is positioned close to the power semiconductor to sense temperature changes, but the measurement signal is transmitted optically rather than electrically, creating an isolation barrier that simplifies the overall system design while maintaining measurement capability.
2Reliability
If temperature sensors are positioned far from power semiconductors, then electrical connection safety is improved, but thermal resistance increases and measurement accuracy deteriorates
Solution Approach 1:
The patent uses optical sensing to enable close positioning of the temperature measurement function near the power semiconductor without requiring electrical connections. The optical waveguide can be positioned immediately adjacent to or even in contact with the semiconductor device, capturing accurate temperature information while maintaining electrical safety through optical rather than electrical coupling.
3Adaptability or versatility
If conventional temperature measurement methods are used, then existing component compatibility is maintained, but dynamic temperature profile measurement capability is limited due to sensor thermal mass and response time
Solution Approach 1:
The patent changes the measurement parameter from electrical resistance (conventional sensors) to optical properties such as refractive index. The optical waveguide's refractive index changes with temperature, allowing for rapid detection of temperature transients. This parameter change enables the sensor to respond faster to temperature changes while the waveguide can be manufactured using standard optical fabrication techniques, maintaining compatibility with existing manufacturing processes.
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 timely and safe disconnection of electronic assemblies from the mains and precise analysis of dynamic temperature profiles, reducing thermal resistance and eliminating the need for electrical connections, thus preventing damage and enhancing safety.
Implementation Method 1
the optical waveguide has a microgrid structure which exhibits temperature-dependent reflection and transmission behavior and can be scanned by means of an optical sensor
Data Source
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AI summary
The invention relates to a temperature measuring device and a temperature measuring method, a manufacturing method for a temperature measuring device, and an electronic assembly with a temperature measuring device based on optical temperature sensing. The temperature measuring device comprises at least one optical waveguide (OF) arranged with a substrate material (PCB), wherein the optical waveguide has a microgrid structure (FBG) which exhibits temperature-dependent reflection and transmission behavior and can be scanned by means of an optical sensor.