3D Freeform Surface Design via Point-by-Point Iteration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for designing freeform optical surfaces ignore normal vectors, leading to inaccurate surface shapes and reduced optical performance due to sensitivity of light refraction and reflection, and result in low image quality with difficulty in further optimization.
Innovation Solution
A method involving point-by-point construction and iteration, where feature rays intersect with initial surfaces to calculate feature data points, considering both coordinates and normal vectors, and iteratively refine the freeform surface using Snell's law and surface fitting techniques to achieve accurate three-dimensional freeform surface design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional direct design methods are used to design freeform surfaces by direct construction, then the design process is straightforward, but the image quality is generally low and further optimization becomes much more difficult
Solution Approach 1:
The patent divides the freeform surface design into discrete feature data points that are calculated point-by-point using feature rays. Each point is determined independently through intersection calculations with the exit pupil plane, allowing precise control of image quality while maintaining a systematic design approach
Solution Approach 2:
The patent performs preliminary calculation of feature data points and their normal vectors before final surface construction. By pre-determining the coordinates and normal vectors of key points on the freeform surface, the method ensures high image quality from the outset and facilitates easier subsequent optimization
2Manufacturing precision
If conventional methods only consider the coordinates of the feature data points, then the design process is simpler, but the shape of the freeform surfaces is inaccurate and optical performance is reduced
Solution Approach 1:
The patent applies different properties to different parts of the feature data points: coordinates determine the position on the surface, while normal vectors determine the local orientation and optical properties. This local differentiation ensures accurate surface shape and optimal optical performance by precisely controlling both where light intersects the surface and how it reflects or refracts
Solution Approach 2:
The patent uses the normal vectors as a feedback mechanism to refine the surface shape. By calculating the required normal vectors at each feature point based on desired optical paths and using them to adjust the surface construction, the method achieves high precision in both surface geometry and optical 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 ensures accurate shape design and improved optical performance by considering both coordinates and normal vectors, resulting in high image quality and precise freeform surfaces that align with general free surface expressions.
Implementation Method 1
calculating a plurality of intersections of the plurality of feature rays Ri (i=1, 2 . . . K) with a first freeform surface point by point based on a given object-image relationship or a given light mapping relationship and a vector form of the Snell's law
Implementation Method 2
Since the refraction and reflection of light are very sensitive to the normal vector of the freeform surfaces
Implementation Method 3
Since the refraction and reflection of light are very sensitive to the normal vector of the freeform surfaces
Data Source
AI summary
A method for designing three-dimensional freeform surface is provided. An initial surface and a first three-dimensional rectangular coordinates system are established. A number of feature rays are selected. A number of intersections of the feature rays with a first freeform surface are calculated, wherein the intersections are a number of feature data points. The first freeform surface is obtained by surface fitting the feature data points. An equation of the first freeform surface includes a conic term and a freeform surface term. The first freeform surface is taken as the initial surface for an iteration process.