Method of freeform imaging system

Patent metadata

Field	Value
Publication number	US-9524565-B2
Application number	US-201414316740-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Oct 24, 2013
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A design method of freeform imaging system is provided. An initial freeform imaging system is provided, the initial freeform image system comprising a first initial surface and a second initial surface spaced from each other. A second surface is constructed by calculating a plurality of second data points of the second surface through a plurality of feature rays based on the given object-image relationship. A first surface is constructed by calculating a plurality of first data points of the first surface based on the given object-image relationship and Fermat's principle, wherein the second surface is fixed. The first surface and the second surface substitute for the first initial surface and second initial surface respectively, and repeating steps list above, wherein the plurality of feature rays are intersecting the image plane at the plurality of ideal image points.

First claim

What is claimed is:

1. A design method of freeform imaging system comprising:
step (S 10 ), establishing a initial freeform imaging system comprising a first initial surface and a second initial surface spaced from each other, wherein a plurality light rays from an object are redirected to form a plurality of image points adjacent to the ideal image points by the first initial surface and the second initial surface;
step (S 20 ), constructing a second surface by calculating and curve fitting a plurality of second data points through a plurality of feature rays based on a given object-image relationship, wherein the first initial surface is fixed, and the plurality of feature rays are substantially intersecting the image plane at the plurality of ideal image points;
step (S 30 ), constructing a first surface by calculating and curve fitting a plurality of first data points based on the given object-image relationship and Fermat's principle, wherein the second surface is fixed, and the plurality of feature rays are substantially intersecting the image plane at the plurality of ideal image points; and
step (S 40 ), substituting the first surface and the second surface for the first initial surface and second initial surface respectively, and repeating step (S 20 ) and step (S 30 ) until the plurality of feature rays are intersecting the image plane at the plurality of ideal image points.

2. The design method of claim 1 , wherein the first initial surface is planar, curved, or spherical, and the second initial surface is planar, curved, or spherical.

3. The design method of claim 1 , wherein the object is an entrance pupil, and a coordinate system is established in the initial freeform imaging system, the origin of the coordinate system is located at the center of the entrance pupil; a z-axis is defined as the direction of the rays outgoing from the entrance pupil and perpendicular with the image plane; and the x-axis and y-axis are perpendicular with each other and perpendicular with the z-axis, a plurality of one-dimensional sampling fields are defined in YOZ coordinate surface.

4. The design method of claim 3 , wherein a field-of-view of the initial freeform imaging system is divided into M sampling fields with equal interval.

5. The design method of claim 4 , wherein each of the M sampling fields is divided by N feature rays, and the N feature rays comprise marginal rays of the entrance pupil.

6. The design method of claim 5 , wherein a diameter of the entrance pupil is divided into N−1 portions in each of the M sampling fields, and a total of K=M×N feature rays are selected according to different sampling fields.

7. The design method of claim 6 , wherein the plurality of feature rays are intersecting the first initial surface at a plurality of start points S i (i=0, 1, 2 . . . K−1), and intersecting the surface Ω+1 at a plurality of end points E i (i=0, 1, 2 . . . K−1).

8. The design method of claim 7 , wherein the plurality of end points E i (i=0, 1, 2 . . . K−1) are obtained based on the Fermat's principle.

9. The design method of claim 8 , wherein the plurality of end points E i (i=0, 1, 2 . . . K−1) of the plurality of feature rays are the plurality of ideal image points and calculated based on the given object-image relationship.

10. The design method of claim 9 , wherein a unit normal vector {right arrow over (N)} i at each of the plurality of second data point P i is calculated based on the vector form of Snell's Law, the second surface is a refractive surface, and:

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where
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Assignees

• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• Zhu Jun
• Yang Tong
• Jin Guo-Fan
• Fan Shou-Shan

Classifications

• G02B27/0012 Primary

  Optical design, e.g. procedures, algorithms, optimisation routines · CPC title

• G06T7/604 Primary

  Physics · mapped topic