Spring-Loaded Optical Thermometry Probe for Vacuum Sealing
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Solution Overview
Problem
Fiber optic temperature sensors face challenges in harsh plasma processing environments due to chemical degradation and contamination, and they are not practical for compact probes in high temperatures or tight spaces, especially when signal quality is compromised by bundled silica fibers.
Innovation Solution
A fiber optic temperature probe design featuring a spring-loaded vacuum mechanism with silica fibers, collimating and decollimating optical elements, and a thermally conductive plate for precise temperature measurement, maintaining a vacuum seal to prevent contamination and enhance signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bundled silica fibers are used in compact probes, then temperature measurement capability is improved, but signal quality deteriorates
Solution Approach 1:
The optical signal path is segmented into two separate single-mode silica fibers instead of using a bundled multi-fiber configuration. The first fiber transmits excitation light to the phosphor, while the second fiber collects emitted light, eliminating signal degradation associated with bundled fibers while maintaining temperature measurement capability through spatial separation of signal paths
Solution Approach 2:
A phosphor material is introduced as an intermediary between the two single-mode fibers. The phosphor receives excitation light from the first fiber and converts it to emitted light that is collected by the second fiber, enabling temperature measurement without requiring direct signal transmission through bundled fibers, thus preserving signal quality
2Volume of moving object
If plastic optical fiber is used to form internal loop for compact probe, then probe compactness is improved, but temperature measurement reliability deteriorates at high temperatures
Solution Approach 1:
The material parameter of the optical fiber is changed from plastic to single-mode silica fiber. Silica fiber maintains its structural integrity and optical transmission properties at high temperatures exceeding 100°C, unlike plastic fiber which degrades, thereby ensuring reliable temperature measurement in high-temperature environments while maintaining probe compactness through the internal loop configuration
3Volume of moving object
If spring-loaded fiber optic temperature probe is used for compact configuration, then probe size is reduced, but chemical contamination risk increases in plasma environment
Solution Approach 1:
Harmful adhesive materials (silicone, epoxy, inorganic ceramic) are completely removed from the probe construction. The probe uses only plasma-compatible materials such as single-mode silica fibers, metal components, and ceramic seals that do not outgas or contaminate the plasma process, eliminating the source of chemical contamination while maintaining compact spring-loaded design
Solution Approach 2:
The probe is designed to operate in a vacuum environment that is chemically inert and compatible with plasma processing. All internal components are selected to be non-outgassing and chemically inert, creating an environment that prevents contamination of the plasma process while maintaining the compact probe structure
4Reliability
If silica fibers are used instead of plastic fiber for high temperature application, then temperature measurement reliability is improved, but probe compactness deteriorates due to larger bend radius
Solution Approach 1:
The single-mode silica fibers are nested within a protective metal or ceramic housing that provides structural support and allows the fibers to be bent into compact configurations without exceeding their minimum bend radius. The housing acts as a protective sleeve that enables compact probe design while preserving the thermal and mechanical properties of the silica fibers for reliable high-temperature operation
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 design ensures reliable temperature measurement in harsh environments by preventing chemical degradation, maintaining signal quality, and allowing compact probe configurations.
Implementation Method 1
a first optical element to collimate light from the first fiber
Implementation Method 2
a second optical element to decollimate light into a first end of a second fiber
Implementation Method 3
maintaining a vacuum seal to prevent contamination
Implementation Method 4
a thermally conductive plate for precise temperature measurement
Data Source
AI summary
A fiber optic temperature probe is disclosed. The fiber optic temperature probe includes a probe shaft containing an optical fiber. An optical temperature sensor element is coupled to the probe shaft and configured to be excited by light from the optical fiber and emit light back to the optical fiber.