Two-Color Wide-Field Refractive Eyepiece for 130° Dual-Band Imaging
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Solution Overview
Problem
Existing infrared imaging optical systems face challenges in achieving wide field-of-view performance with reduced barrel-type field distortion and operating effectively in both mid-wave and long-wave infrared spectral bands, particularly when housed within a cooled chamber like a dewar.
Innovation Solution
A refractive optical system comprising eight lenses, including five positive powered lenses and three negative powered lenses made from specific materials like AMTIR-1 and barium fluoride, configured to operate in both MWIR and LWIR spectral bands with a wide field of view and reduced distortion, housed within a dewar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional eyepiece design with external entrance pupil is used, then the system is simple in structure, but off-axis aberrations (coma, astigmatism, lateral color) are difficult to correct
Solution Approach 1:
The optical system is divided into multiple lens elements (five positive powered lenses and three negative powered lenses) with different materials (optical crown, optical flint, chalcogenide glass, barium fluoride). Each lens segment is optimized for specific aberration correction, allowing the system to achieve comprehensive correction of coma, astigmatism, and lateral color while maintaining manageable complexity through modular design
Solution Approach 2:
The patent employs composite optical materials including chalcogenide glass (AMTIR-1) and barium fluoride in specific lens elements. These specialized materials have unique dispersion and transmission properties that enable effective correction of off-axis aberrations in the infrared spectral bands, achieving superior optical performance through material composition rather than单纯 structural complexity
2Area of stationary object
If the field of view is increased to 130 degrees, then the coverage area is expanded, but barrel-type field distortion increases
Solution Approach 1:
Different lens elements are assigned specific optical powers and materials tailored to their position in the optical train. The five positive powered lenses and three negative powered lenses work in conjunction to locally correct distortion at different stages of the optical path, enabling the system to maintain 130 degrees field of view while controlling barrel-type distortion to 11-19% through localized optical optimization
Solution Approach 2:
The optical system utilizes specific material parameters (refractive index, dispersion characteristics) of chalcogenide glass and barium fluoride to control aberration coefficients. By carefully selecting and combining materials with different optical parameters, the system achieves wide field of view operation with reduced distortion through parameter optimization rather than geometric compromise
3Adaptability or versatility
If the system operates in both MWIR and LWIR spectral bands, then the versatility is improved, but the optical design complexity increases
Solution Approach 1:
The optical system is designed as a universal platform that can operate across both mid-wave infrared (3-5 μm) and long-wave infrared (7-12 μm) spectral bands. The combination of chalcogenide glass and barium fluoride lenses provides transmission characteristics suitable for both bands, allowing a single optical design to serve dual spectral functions without requiring separate optimized systems
Solution Approach 2:
The patent employs composite optical materials including chalcogenide glass (AMTIR-1) and barium fluoride in specific lens elements. These specialized materials have unique dispersion and transmission properties that enable effective correction of off-axis aberrations in the infrared spectral bands, achieving superior optical performance through material composition rather than单纯 structural 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
The system achieves a wide field of view of 130 degrees with significantly reduced distortion (11-19%) and operates at F/2.0 optical speed, providing high-resolution dual-band infrared imaging within a cryogenic environment.
Implementation Method 1
A refractive optical system comprising eight lenses, including five positive powered lenses and three negative powered lenses
Data Source
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AI summary
A dual-band refractive optical system having an eyepiece-type arrangement and configured for mid-wave infrared and long-wave infrared operation. In one example the optical system includes a plurality of lenses, each constructed from a material that is optically transparent in the mid-wave infrared and long-wave infrared spectral bands. The lenses are arranged to receive infrared electromagnetic radiation in an operating waveband that includes at least a portion of the mid-wave infrared and at least a portion of the long-wave infrared spectral bands via a front external aperture stop and to focus the infrared electromagnetic radiation onto a rear image plane, the lenses being positioned between the front external aperture stop and rear image plane. The optical system can further include a corrector plate positioned coincident with the front aperture stop.