Off-axis Aspheric Optical System Design Method
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Solution Overview
Problem
Conventional methods for designing off-axis aspheric optical systems are limited by the number of fields of view and apertures considered, which restricts the reduction of aberrations and improvement of design freedom in off-axis three-mirror optical systems.
Innovation Solution
A method involving the establishment of an initial system with multiple aspheric surfaces, selection of feature rays from various fields and aperture positions, and iterative fitting of feature data points using Snell's law to obtain optimized aspheric surfaces, incorporating intermediate points to refine the design and reduce fitting errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional methods are used for designing off-axis aspheric optical systems, then the design process is simpler, but the number of fields of view and apertures that can be considered is limited
Solution Approach 1:
The design method segments the complex optical surface into multiple coordinate systems (global coordinate system and local coordinate systems for different mirror surfaces). Each mirror surface is designed independently using its own local coordinate system, then integrated into the global system. This segmentation allows the design to handle multiple fields of view and apertures by treating each as a separate design variable in the respective local coordinate system.
Solution Approach 2:
The patent introduces a new dimensional approach by using local coordinate systems attached to each mirror surface, in addition to the global coordinate system. This multi-dimensional coordinate framework allows independent optimization of each mirror surface for different fields and apertures, effectively adding design dimensions that conventional single-coordinate-system methods cannot provide.
2Reliability
If aspheric surfaces are used in off-axis three-mirror optical systems, then aberrations are significantly reduced and design freedom is improved, but conventional design methods cannot adequately utilize these advantages across multiple fields and apertures
Solution Approach 1:
The patent applies local quality by allowing each mirror surface to have its own local coordinate system with independent aspheric parameters optimized for specific local requirements. Different regions of the optical system (different mirrors, different fields, different apertures) can have locally optimized aspheric surfaces tailored to their specific aberration characteristics, rather than using a uniform design approach.
Solution Approach 2:
The method enables independent parameter optimization for each mirror surface in the local coordinate systems. The aspheric parameters, conic constants, and other surface definition parameters can be changed and optimized separately for each mirror and each field-aperture combination, allowing full utilization of aspheric freedom to reduce aberrations across multiple fields and apertures simultaneously.
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
This approach significantly reduces aberrations and improves design freedom, enabling the creation of off-axis aspheric three-mirror optical systems with enhanced imaging quality and larger fields of view, as demonstrated by improved RMS spot diameters, distortion, and modulation transfer function performance.
Implementation Method 1
solving a plurality of feature data points (P1, P2, . . . Pm) point by point based on given object-image relationship and Snell's law
Data Source
AI summary
A point-by-point design method for off-axis aspheric optical system, in which feature light rays from different field angles and aperture coordinates are considered. Some of the feature data points are calculated first and surface fitted into an initial aspheric surface. Then, intermediate point calculations, feature data point calculations, and aspheric surface fitting were repeated continuously to calculate remaining feature data points and the desired aspheric surface are repeated continuously to calculate remaining feature data points and a desired aspheric surface. A least-squares method with a local search algorithm is used for aspheric surface fitting and deviations in both the coordinates and normals are used to reduce error.