Freeform Surface Reflective Imaging System Design
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Solution Overview
Problem
Current design methods for freeform surface reflective imaging systems can only achieve a limited number of field of views (FOV) and fail to simultaneously achieve a low F-number and a wide rectangular FOV.
Innovation Solution
A method involving the selection of an initial system with a low F-number and small rectangular FOV, followed by a sequential point-by-point construction of freeform surfaces across increasing FOVs using a specific FOV sequence, with surface fitting techniques to achieve a freeform surface reflective imaging system with a low F-number and wide rectangular FOV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If direct design methods (differential equation method, multi-surface synchronous design method, point-by-point construction and iterative methods) are used, then freeform off-axis imaging systems can be obtained, but only a limited number of field of views (FOV) can be achieved and low F-number with wide rectangular FOV cannot be achieved simultaneously
Solution Approach 1:
The patent segments the field of view into multiple discrete fields, designing each field independently through separate optical paths. This allows the system to achieve multiple FOVs by combining several simplified single-FOV designs, rather than attempting to design one complex system for all FOVs simultaneously.
Solution Approach 2:
The patent transitions from conventional two-dimensional rotationally symmetric surfaces to three-dimensional freeform surfaces with asymmetric profiles. This dimensional expansion provides additional design degrees of freedom, enabling the system to achieve wide rectangular FOV and low F-number simultaneously by utilizing surface curvature variations in multiple directions.
2Device complexity
If conventional rotationally symmetric surfaces are used, then system structure is simpler, but aberrations increase and design freedom is limited
Solution Approach 1:
The patent employs asymmetric freeform surfaces that break the conventional rotational symmetry. These asymmetric surfaces provide additional degrees of freedom for aberration correction, allowing independent optimization of different field regions and enabling better control over optical aberrations across wide rectangular FOV.
Solution Approach 2:
The patent applies different surface characteristics to different regions of the optical system. Each field of view is designed with optimized local surface properties, allowing tailored aberration correction for specific FOV regions while maintaining overall system performance.
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 method enables the design of a freeform surface reflective imaging system with a low F-number and large rectangular FOV, meeting performance requirements and allowing for subsequent optimization.
Implementation Method 1
freeform surface reflective imaging system
Data Source
AI summary
The present invention relates to a method for designing a freeform surface reflective imaging system, comprising: selecting an initial system, wherein an FOV of the initial system is X0×Y0; selecting an FOV sequence as [X0, Y0], [X1, Y1], [X2, Y2], . . . , [Xn, Yn], while the FOV of the system to be designed is Xn×Yn, and X0<X1<X2< . . . <Xn, Y0<Y1<Y2< . . . <Yn; using point-by-point methods to construct all freeform surfaces of the initial system in the FOV of X1×Y1; setting the system obtained in the last step as a second initial system for system construction in the FOV of X2×Y2; repeating the last step to execute system construction in the order of the FOV sequence until the final FOV Xn×Yn is obtained.