Off-Axial Freeform Optical System Design via Ray Intersection
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Solution Overview
Problem
Conventional direct design methods for freeform optical surfaces result in low image quality with large average RMS spot diameters, making further optimization difficult in off-axial optical systems.
Innovation Solution
A method involving point-by-point construction and iteration processes to design off-axial optical systems with freeform surfaces, using feature rays and Snell's law to calculate intersections and fit surfaces with base conic and freeform terms, iteratively refining the system to improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional direct design methods are used for freeform optical surfaces, then the design process is simpler, but the image quality is low with large average RMS spot diameters
Solution Approach 1:
The patent segments the optical surface design into multiple iterative steps: establishing initial surfaces, calculating feature ray intersections point-by-point, fitting surfaces to these points, and repeating the process. This segmentation transforms a complex optimization problem into manageable sequential steps, improving image quality while keeping the process systematic
Solution Approach 2:
The patent performs preliminary actions by first establishing initial optical surfaces and calculating feature ray intersections before fitting the final surface equations. This preliminary construction of geometric relationships provides a solid foundation for subsequent optimization, achieving high image quality from the outset
2Reliability
If freeform surfaces are used in off-axial optical systems, then the degrees of freedom increase and aberrations can be reduced, but the design complexity increases
Solution Approach 1:
The patent applies local quality by fitting different surface characteristics to different regions of the optical surface. The feature ray method calculates intersections at specific points across the aperture, allowing the surface equation to be optimized with local precision while maintaining overall system performance and controlling aberrations
Solution Approach 2:
The patent changes parameters by iteratively adjusting the surface equation coefficients based on feature ray intersections. The method transforms the surface fitting problem into a parameter optimization problem, where coefficients are refined through multiple iterations to achieve desired aberration control while managing design 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
Significantly reduces distortion and average RMS spot diameters, enhancing the imaging quality and optical properties of off-axial optical systems with freeform surfaces.
Implementation Method 1
calculating a plurality of intersections of the plurality of feature rays Ri (i=1, 2...K) with the first freeform surface a point by point based on a given object-image relationship and a vector form of Snell's law
Data Source
AI summary
A method for designing off-axial optical system with freeform surfaces is provided. An initial system is established. A freeform surface of the off-axial optical system that needs to be solved is defined as a freeform surface. A number of feature rays are selected. A number of intersections of the feature rays with the freeform surface are calculated point by point based on a given object-image relationship and a vector form of Snell's law. A number of first feature data points are obtained from the intersections and surface fitted to obtain the freeform surface. All the freeform surfaces of the off-axial optical system that need to be solved are obtained by the method above to form a before-iteration off-axial optical system. The before-iteration off-axial optical system is used as the initial system for multiple iterations to obtain an after-iteration off-axial optical system.