Multichannel Catadioptric Structure for Compact Thermal Imaging
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Solution Overview
Problem
Uncooled thermal imaging cameras with VGA resolution are large, expensive, and not compact, requiring large, heavy germanium or chalcogenide lenses, and silicon absorption limits their use, while alternative approaches with scanning mirrors are cumbersome and wear-prone.
Innovation Solution
A multi-channel catadioptric structure with optical correction elements, detectors, and mirrors, where detectors are encapsulated between correction and mirror elements, forming channels that capture different image sections, allowing for higher resolution and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large germanium or chalcogenide lenses are used to achieve VGA resolution, then imaging quality is improved, but system size and cost increase significantly
Solution Approach 1:
The patent divides the field of view into multiple segments, with each segment captured by a separate optical channel containing a micro-lens and detector. This segmentation allows the use of small micro-lenses instead of one large lens, achieving VGA resolution through parallel processing of multiple low-resolution channels while dramatically reducing system size
Solution Approach 2:
The patent transitions from a single large optical element in three dimensions to multiple small optical elements arranged in a two-dimensional array. This dimensional change allows parallel capture of multiple field of view segments, achieving high resolution without requiring large individual lens elements
2Speed
If germanium or chalcogenide lenses are used for high-speed optics, then optical performance is improved, but cost and weight increase
Solution Approach 1:
The patent replaces expensive, heavy germanium or chalcogenide glass lenses with inexpensive plastic micro-lenses that can be mass-produced through injection molding. Although plastic has higher thermal expansion, the small size and modular design make the system tolerant to thermal effects while dramatically reducing cost and weight
Solution Approach 2:
The patent changes the material parameter from germanium/chalcogenide glass to plastic, accepting the trade-off of higher thermal expansion in exchange for reduced weight and cost. The modular micro-lens design compensates for thermal effects, maintaining optical performance
3Ease of manufacture
If silicon is used for lens manufacturing, then cost is reduced, but absorption in 8-14 μm range limits usability
Solution Approach 1:
The patent applies different material qualities to different parts of the optical system: plastic micro-lenses for the optical path (transparent in FIR) and silicon for the detector substrate and packaging (where absorption is not an issue). This local differentiation allows cost-effective silicon manufacturing processes while avoiding silicon's absorption limitation in the optical path
4Adaptability or versatility
If scanning mirror optics are used to expand field of view, then field of view is improved, but mechanical complexity and wear increase
Solution Approach 1:
The patent replaces dynamic scanning mirror optics with a static multi-channel catadioptric system. Instead of mechanically scanning a single detector across the field of view, multiple detectors simultaneously capture different field of view segments, eliminating moving parts and mechanical complexity while expanding the effective field of view
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 enables high-resolution infrared imaging with reduced size and cost, using a modular design with encapsulated detectors for improved field of view and reduced thermal aberrations, suitable for automotive and surveillance applications.
Implementation Method 1
optical correction elements (2a-2c) ... each optical detector (1a-1c) together with a respective optical correction element (2a-2c) and a respective optical mirror element (3a-3c) forms a channel
Implementation Method 2
optical mirror elements (3a-3c) ... each optical detector (1a-1c) together with a respective optical correction element (2a-2c) and a respective optical mirror element (3a-3c) forms a channel
Implementation Method 3
uncooled thermal imaging cameras ... pixel size of 12 to 17 μm (e.g., for wavelengths of 8 to 14 μm) and are based on special microbolometer technology
Data Source
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AI summary
Embodiments relate to a multichannel catadioptric system for capturing an infrared image (e.g. thermal image). The multichannel catadioptric system comprises a plurality of optical correction elements, a plurality of optical detectors (e.g. image recorders; e.g. each one comprising a plurality of pixels), and a plurality of optical mirror elements, wherein the plurality of optical detectors is attached or integrated onto one of the plurality of optical correction elements, and each optical detector is encapsulated between one of the plurality of optical correction elements and one of the plurality of optical mirror elements. Each optical detector of the plurality of optical detectors together with a respective optical correction element and a respective optical mirror element forms a channel of the multichannel catadioptric system, wherein the plurality of optical correction elements are formed on a common correction element support and/or the plurality of optical mirror elements are formed on a common mirror element support.