Copper Heat Shield Ports for XRF Head Thermal Protection
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Solution Overview
Problem
X-ray based metrology tools used in high temperature environments for CIGS PV cell manufacturing are vulnerable to damage from extreme heat (100-300°C), requiring protection to maintain functionality and allow for real-time film analysis without cooling the substrates.
Innovation Solution
A thermal shield system comprising a machined copper heat shield and aluminum heat shield cowling, which directs X-rays through ports while deflecting infrared radiation and preventing hot air from reaching the X-ray head, using strategic port placement and internal cooling systems to maintain tool stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the XRF tool is placed close to the hot substrate for real-time measurement, then measurement capability and productivity are improved, but the tool is exposed to extreme heat (100-300°C) that will damage the delicate instrument
Solution Approach 1:
The system divides the protective function into separate components: a heat shield element positioned between the substrate and X-ray head, and a cowling structure enclosing the X-ray head. This segmentation allows the X-ray head to be protected from heat while maintaining close proximity to the hot substrate for real-time measurements.
Solution Approach 2:
The heat shield element acts as an intermediary component that blocks thermal radiation from the substrate while allowing X-ray beams to pass through. This mediator protects the X-ray head from direct heat exposure while maintaining the necessary measurement capability.
2Object-affected harmful factors
If a thick heat shield is used to block infrared radiation, then thermal protection is improved, but excessive heat absorption and air flow blockage occur
Solution Approach 1:
The heat shield element is designed with specific parameters: it is positioned at a precise distance from the substrate and X-ray head, has optimized thickness to block infrared radiation while allowing X-rays through, and includes strategically placed ports. These parameter optimizations achieve effective thermal protection without excessive complexity.
Solution Approach 2:
The heat shield element has different functional zones: ports are positioned to allow X-ray transmission in specific directions while blocking infrared radiation; the cowling has strategically placed air intake and exhaust ports to manage convection currents. This local differentiation of functionality achieves effective protection without uniform complexity throughout the structure.
3Measurement precision
If ports are added to the heat shield to allow X-ray transmission, then measurement capability is improved, but hot air flow through the ports increases thermal exposure to the X-ray head
Solution Approach 1:
The system uses pneumatic principles by introducing cooled air through ports in the cowling and using fans to create controlled air currents. This pneumatic approach allows the system to actively manage thermal conditions at the X-ray head, preventing hot air from reaching the detector while maintaining X-ray transmission through the heat shield ports.
Solution Approach 2:
The system incorporates dynamic cooling elements including fans that can adjust air flow rates and cooling ports that can be opened or closed as needed. This dynamic control allows the system to adapt to varying thermal conditions while maintaining both X-ray transmission and thermal protection.
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 uninterrupted XRF measurements at high temperatures, reducing panel dwell times, improving throughput, and allowing real-time data collection for process control, thereby protecting the metrology tool and optimizing PV material performance.
Implementation Method 1
Copper is used to deflect the infrared radiation that is emitted from the PV substrate
Implementation Method 2
The x-ray head assembly includes the x-ray generation and detection columns and the head control electronics, communications and cooling systems
Data Source
AI summary
A thermal shield for an XRF measurement tool is formed from a heat shield and a heat shield cowling. These components protect the X-ray head assembly that includes the x-ray generation and detection columns and the head control electronics, communications and cooling systems. The heat shield is directly below the X-ray head, parallel to the x-ray head plane and plane of the PV substrate, and perpendicular to the primary beam output from the x-ray head. The heat shield is fabricated of machined copper with several ports machined through the shield. These ports provide a path for primary beam x-rays through the heat shield and for the return of fluoresced X-rays from the PV substrate back to the detector in the X-ray head, while preventing damage to the X-ray head due to the heat emitted from the PV substrate.