Catadioptric optical system

Patent metadata

Field	Value
Publication number	US-11513326-B2
Application number	US-202017136935-A
Country	US
Kind code	B2
Filing date	Dec 29, 2020
Priority date	Jan 2, 2020
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A catadioptric optical system in sequence of ray tracing comprises a first mirrors group of Ritchey-Chrétien type hyperbolic mirrors with positive diopter including a concave primary mirror having a central through hole and a convex secondary mirror, a second corrector lens group with negative diopter positioned at the image-side of the first mirrors group including a first meniscus lens element having positive refractive power and a convex object-side surface, a second lens element having negative refractive power and biconcave surfaces, a third meniscus lens element having negative refractive power and a concave object-side surface, and a fourth lens element having positive refractive power and biconvex surfaces. The infinite conjugate beams of incident light within field of view pass through the catadioptric optical system to become a corrected beam having a small CRA angle.

First claim

What is claimed is:

1. A catadioptric optical system, comprising in sequence of ray tracing:
a first mirrors group of Ritchey-Chrétien type hyperbolic mirrors with positive diopter including a concave primary mirror having a central through hole and a convex secondary mirror; and
a second corrector lens group with negative diopter positioned at an image side of the first mirrors group and from the image side of the first mirrors group in order including a first meniscus lens element having positive refractive power and a convex object-side surface, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, a third meniscus lens element having negative refractive power and a concave object-side surface, and a fourth lens element with positive refractive power having a convex object-side surface and a convex image-side surface;
wherein a diopter of the whole catadioptric optical system is DW, a diopter of the second corrector lens group is DL, and the following condition is satisfied:

DL
⁢

DW

=

(

P
4

⁢

EFL
4

+

P
3

⁢

EFL
3

+

P
2

⁢

EFL
2

+

P
1

⁢
EFL

+

P
0

)

*

(

1
±

10
⁢
%

)

;

wherein
P 0 =−4.95*10 −1 ;

P 1 =−1.81*10 −3 ;

P 2 =5.59*10 −7 ;
P 3 =−7.76*10 −11 ;

P 4 =4.4*10 −15 ; and

EFL is an effective focal length of the catadioptric optical system.

2. The catadioptric optical system of claim 1 , wherein the first lens element is constituted of a singular lens element and has an image-side surface being concave.

3. The catadioptric optical system of claim 1 , wherein the third lens element is constituted of a singular lens element and has an image-side surface being convex.

4. The catadioptric optical system of claim 1 , wherein a diopter of the first lens element is DL1, a diopter of the second lens element is DL2, a diopter of the third lens element is DL3, a diopter of the fourth lens element is DL4, and the following conditions are satisfied:

DL
⁢

⁢
1

DL

=

(

K
4

⁢

EFL
4

+

K
3

⁢

EFL
3

+

K
2

⁢

EFL
2

+

K
1

⁢
EFL

+

K
0

)

*

(

1
±

10
⁢
%

)

;

wherein

⁢

K
0

=

-
3.32

;

⁢

K
1

=

1.23
*

10

-
3

;

⁢

K
2

=

-
3.86

*

10

Assignees

• Nat Applied Res Laboratories

Inventors

• Lin Sheng-Feng
• Chen Chia-Ray
• Kuo Tien-Chun

Classifications

• G02B17/0896 Primary

  with variable magnification or multiple imaging planes, including multispectral systems (systems with only refractive elements G02B15/14) · CPC title

• G02B17/0876

  for light collecting, e.g. for use with a detector · CPC title

• G02B17/0808

  on-axis systems with at least one of the mirrors having a central aperture · CPC title