Infrared Imager Single Detector Dual Spectral Band Switching Optics
Solution Overview
Problem
Existing infrared imagers operating in multiple spectral bands are resource-intensive, bulky, and expensive due to the need for separate detectors and optics for each band.
Innovation Solution
An infrared imager with a single detector capable of operating in two continuous and separate spectral bands, utilizing a splitter, switching optics, and reflectors to manage infrared fluxes, reducing resource consumption and size by using a single detector cooled to a lower temperature and employing mobile switching optics and reflectors to minimize parasitic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate detectors and optics are used for each spectral band, then detection performance for each band is optimized, but device complexity, size, and cost increase
Solution Approach 1:
The patent combines multiple spectral band detection capabilities into a single detector by using a cryogenic cooling system that enables the detector to operate across multiple bands (e.g., 3-5 μm and 8-12 μm) simultaneously, eliminating the need for separate detectors for each band
Solution Approach 2:
The single detector is designed with universal capability to detect infrared radiation across multiple disjoint spectral bands through cryogenic cooling, allowing one detector to perform the function of what would traditionally require multiple specialized detectors
2Measurement precision
If separate detectors and optics are used for each spectral band, then detection performance for each band is optimized, but device size increases
Solution Approach 1:
The patent merges multiple detection functions into a single compact detector unit cooled to cryogenic temperatures, reducing the overall device volume by eliminating redundant optical paths and detector assemblies for different spectral bands
3Device complexity
If a single detector is used for both spectral bands, then device complexity and size are reduced, but parasitic noise from the warm enclosure increases
Solution Approach 1:
The patent segments the device into two distinct thermal zones: a warm enclosure (first temperature) housing optical components and a cold detector region (second temperature) isolated by a cryostat, allowing the detector to operate at low noise levels while the enclosure remains at operational temperature
Solution Approach 2:
The detector is extracted from the warm enclosure environment and placed in a separate cryogenic environment, removing it from the source of thermal noise generated by the warm optical components and enclosure structure
4Adaptability or versatility
If switching optics are used to direct different spectral bands to the single detector, then a single detector can serve both bands, but the system becomes more complex
Solution Approach 1:
The patent replaces mechanical switching mechanisms with passive optical filtering using dichroic beamsplitters that automatically direct different spectral bands to appropriate detection paths based on wavelength, eliminating moving parts and reducing mechanical complexity
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 efficient detection of two spectral bands with reduced resource and size requirements, achieving performance equivalent to specialized imagers for each band while minimizing noise, thus being less resource-intensive and more compact.
Implementation Method 1
a separator dividing an incident infrared flux into two distinct fluxes, the first flux being the portion of the incident infrared flux in the first spectral band and the second flux being the portion of the incident infrared flux in the second spectral band
Implementation Method 2
a single detector capable of detecting a flux in both spectral bands, the single detector being cooled to a second temperature
Implementation Method 3
a first reflector having a first background at a temperature strictly lower than the first temperature, the first reflector being positioned so that the image of the first background in the first spectral band, as seen by the switching optics in the second position, is located on the single detector
Implementation Method 4
a switching optic movable between a first position in which the first flux is sent towards the single detector and a second position in which the second flux is sent towards the single detector
Data Source
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AI summary
The present invention relates to an infrared imager (10) suitable for detecting an infrared flux in a first and a second spectral band, the imager comprising an enclosure (12) and including: - a separator (18) separating an incident infrared flux into two fluxes, - a single detector (16) suitable for detecting a flux in the two spectral bands, the detector (16) being cooled to a temperature lower than the temperature of the enclosure, - a switching optic (20) movable between a first position in which the first flux is sent to the detector (16) and a second position in which the second flux is sent to the detector (16), and - a reflector (26) having a bottom positioned in order that the image of the bottom in the first spectral band by the switching optic (20) in the second position is situated on the detector (16).