Off-axial three-mirror system

Patent metadata

Field	Value
Publication number	US-9250428-B2
Application number	US-201213712960-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Nov 6, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

An off-axial three-mirror system includes a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor. The secondary mirror is located on a reflective optical path of the primary mirror. The tertiary mirror is located on a reflective optical path of the secondary mirror. The image sensor is located on a reflecting optical path of the tertiary mirror. The primary mirror and the tertiary mirror are formed as one piece. The surface type of both the primary mirror and the tertiary mirror is a freeform surface.

First claim

What is claimed is:

1. An off-axial three-mirror system comprising: a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor; wherein the secondary mirror is located on a primary mirror reflective optical path, the tertiary mirror is located on a secondary mirror reflective optical path, the image sensor is located on a tertiary mirror reflecting optical path; the primary mirror and the tertiary mirror are formed as one piece; and a surface type of both the primary mirror and the tertiary mirror is a freeform surface, wherein the primary mirror, the secondary mirror, and the tertiary mirror are concave minors; the surface type of both the primary mirror and the tertiary mirror is a XY polynomial surface, and an equation of the XY polynomial surface is

z
=

x
2

+

y
2

R
⁡

(

1
+

1
-

(

1
+

C
1

)

⁢

(

x
2

+

y
2

)

/

R
2

)

+

C
2

⁢
x

+

C
3

⁢
y

+

C
4

⁢

x
2

+

C
5

⁢
xy

+

C
6

⁢

y
2

+

C
7

⁢

x
3

+

C
8

⁢

x
2

⁢
y

+

C
9

⁢

xy
2

+

C
10

⁢

y
3

+

C
11

⁢

x
4

+

C
12

⁢

x
3

⁢
y

+

C
13

⁢

x
2

⁢

y
2

+

C
14

⁢

xy
3

+

C
15

⁢

y
4

,

R in the equation represents radius of the primary mirror and the tertiary mirror, and C 1 ˜C 15 represent coefficients in the equation.

2. The system as claimed in claim 1 , wherein R=361.890, C 1 =−0.481, C 2 =−4.476×10 −7 , C 3 =−4.904×10 −2 , C 4 =−2.247×10 −3 , C 5 =1.690×10 −9 , C 6 =−2.348×10 −3 , C 7 =−1.374×10 −12 , C 8 =5.312×10 −7 , C 9 =−3.204×10 −12 , C 10 =4.731×10 −7 , C 11 =−1.724×10 −9 , C 12 =1.327×10 −14 , C 13 =−3.698×10 −9 , C 14 =2.308×10 −14 , and C 15 =−2.122×10 −9 in the equation of the primary mirror.

3. The system as claimed in claim 1 , wherein R=−188.938, C 1 =0.305, C 2 =−3.908×10 −7 , C 3 =7.408×10 −2 , C 4 =2.620×10 −5 , C 5 =−1.176×10 −9 , C 6 =1.272×10 −4 , C 7 =−1.707×10 −12 , C 8 =7.241×10 −7 , C 9 =−6.562×10 −12 , C 10 =6.047×10 −7 , C 11 =1.591×10 −9 , C

Assignees

• Zhu Jun
• Hou Wei
• Jin Guo-Fan
• Fan Shou-Shan
• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• Zhu Jun
• Hou Wei
• Jin Guo-Fan
• Fan Shou-Shan

Classifications

• G02B17/0621 Primary

  off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements · CPC title

• G02B17/0642

  off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements · CPC title