Self-Referenced Ambient Radiation Thermometer with Isothermal Enclosure
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Solution Overview
Problem
Conventional thermal-infrared radiation thermometers face challenges with long-term stability and large size-of-source effects (SSE), and their optical designs have not evolved to address these issues, leading to poor performance in measuring temperatures across a wide range.
Innovation Solution
A self-referenced ambient radiation thermometer with a thermally stabilized isothermal enclosure and optical components, including a field stop, Lyot stop, collimating lens, and detector, modulated by a chopper wheel, to reduce SSE and enhance long-term stability, using ZnSe lenses and a pyroelectric detector with a 8 μm to 14 μm filter for thermal-infrared radiation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal-infrared radiation thermometers are used, then temperature measurement capability is provided, but long-term stability deteriorates and size-of-source effects increase
Solution Approach 1:
The optical system is segmented into multiple distinct components (objective lens, field stop, chopper, detector lens, detector) with specific functions. The field stop segments the field of view to exclude peripheral radiation, while the chopper segments the radiation stream to create modulated signals for precise detection, thereby improving both stability and measurement precision.
Solution Approach 2:
The patent introduces intermediary elements between the blackbody object and detector: the field stop acts as an intermediary to block peripheral radiation paths, the chopper serves as an intermediary to modulate the radiation signal, and the lens system acts as an intermediary to focus and control radiation. These intermediaries improve measurement precision without compromising long-term stability.
2Reliability
If optical components are thermally stabilized in an isothermal enclosure, then long-term stability improves, but device complexity increases
Solution Approach 1:
Multiple optical components (objective lens, field stop, chopper, detector lens, and detector) are merged into a single integrated optical assembly housed in one isothermal enclosure. This consolidation provides thermal stabilization for all components simultaneously, improving long-term stability while managing complexity through unified design rather than separate stabilized systems.
Solution Approach 2:
The patent changes the temperature parameter of the optical enclosure to be thermally stabilized at a constant value. By controlling the temperature parameter of the entire optical assembly, the system achieves improved long-term stability and reduced thermal drift without requiring complex individual component stabilization systems.
3Measurement precision
If a field stop and Lyot stop are added to block scattered radiation, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent extracts and blocks the harmful scattered radiation component from the total radiation using the field stop and Lyot stop. By taking out only the peripheral and scattered radiation portions while allowing central radiation to pass, the system improves measurement precision by eliminating noise sources without requiring complete system redesign.
Solution Approach 2:
The field stop and Lyot stop provide local quality control by selectively blocking radiation from specific directions and paths. The field stop addresses peripheral radiation locally at the field of view boundary, while the Lyot stop addresses scattered radiation locally at the focal plane, improving precision through targeted intervention rather than global system changes.
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 provides sub-millikelvin temperature measurement resolution with week-long stable operations, reducing SSE and improving long-term stability, enabling accurate temperature measurements from -50°C to 150°C without cryogenic cooling.
Implementation Method 1
a pyroelectric detector with a 8 μm to 14 μm filter for thermal-infrared radiation detection
Implementation Method 2
using ZnSe lenses and a pyroelectric detector with a 8 μm to 14 μm filter for thermal-infrared radiation detection
Implementation Method 3
modulated by a chopper wheel
Implementation Method 4
determining a temperature of a blackbody object
Data Source
AI summary
A self-referenced ambient radiation thermometer determines a temperature of a blackbody object and includes a temperature stabilized detector; a detector lens; a Lyot stop; a collimating lens; a field stop; an optical chopper such that the central radiation received by the temperature stabilized detector is modulated at a modulation frequency of the optical chopper; an objective lens in optical communication with the blackbody object and the temperature stabilized detector, optically interposed between the blackbody object and the field stop and that: receives the central radiation from the blackbody object and communicates the central radiation to the field stop; and a temperature-stabilized isothermal enclosure that provides a stable temperature and isothermal environment to elements disposed in the temperature-stabilized isothermal enclosure, wherein the elements disposed in the temperature-stabilized isothermal enclosure comprise: the temperature stabilized detector, the detector lens, the collimating lens, the Lyot stop, and the field stop.