Off-axial three-mirror system

Patent metadata

Field	Value
Publication number	US-8975571-B2
Application number	US-201213712961-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Nov 6, 2012
Publication date	Mar 10, 2015
Grant date	Mar 10, 2015

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. The primary mirror is a convex mirror, and the tertiary mirror is a concave mirror.

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, a surface type of both the primary mirror and the tertiary mirror is a freeform surface; the primary mirror is a convex mirror; and the tertiary mirror is a concave mirror.

2. The system as claimed in claim 1 , wherein the surface type of both the primary mirror and the tertiary mirror is a XY polynomial surface.

3. The system as claimed in claim 2 , wherein 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.

4. The system as claimed in claim 3 , wherein R=358.016, C 1 =−0.366, C 2 =5.790×10 −2 , C 3 =6.188×10 −2 , C 4 =1.088×10 −3 , C 5 =8.842×10 −5 , C 6 =2.318×10 −4 , C 7 =−8.609×10 −7 , C 8 =1.343×10 −7 , C 9 =2.578×10 −7 , C 10 =9.240×10 −7 , C 11 =−4.185×10 −8 , C 12 =1.235×10 −8 , C 13 =−9.941×10 −9 , C 14 =−9.248×10 −12 , C 15 =−7.091×10 −9 in the equation of the primary mirror.

5. The system as claimed in claim 3 , wherein R=−241.763, C 1 =0.430, C 2 =−1.655×10 −2 , C 3 =4.061×10 −2 , C 4 =4.056×10 −5 , C 5 =−9.874×10 −6 , C 6 =−8.263×10 −5 , C 7 =−3.297×10 −7 , C 8 =3.963×10 −7 , C 9 =−1.295×10 −7 , C 10 =3.713×10 −7 , C 11 =4.014×10 −9 , C 12 =2.517×10 −9 , C 13 =3.940×10 −9 , C 14 =2.192×10 −10 , C 15 =1.971×10 −10 in the equation of the tertiary mirror.

6. The system as claimed in claim 2 , wherein an entrance pupil diameter of the off-axial three-mirror system is 7.5 mm.

7. The system as claimed in claim 1 , wherein a surface type of the seco

Assignees

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

Inventors

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

Classifications

• H10F39/152 Primary

  One-dimensional array CCD image sensors · CPC title

• H01L27/14825 Primary

  Electricity · mapped topic

• 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