Optical system having a reflecting surface

• US 6,268,963 B1
• Filed: 08/20/1998
• Issued: 07/31/2001
• Est. Priority Date: 08/22/1997
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Akiyama, Takeshi
• Primary Examiner(s): Mack, Ricky
• Application Number:
  US09/137,495
• Time in Patent Office: 1,076 Days
• Field of Search: 350/55, 350/505, 350/538, 359/561, 359/858, 359/729, 359/631, 359/633, 359/726, 359/727, 359/730, 359/731, 359/732, 359/366, 359/630, 359/636, 359/637
• US Class Current: 359/631
• CPC Class Codes: G02B 17/0848 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 Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems

Abstract

An optical system has a stop and a plurality of curved reflecting surfaces, the optical paths of rays of light successively reflected by the plurality of curved reflecting surfaces and arriving at the center of an image plane via the center of the stop intersecting with each other twice.

Claims

1. An optical system comprising:

a stop; and

an optical element which is integrally provided with a plurality of curved reflecting surfaces,

wherein in said optical element, an optical path of a ray of light, successively reflected by said plurality of curved reflecting surfaces and arriving at the center of an image plane via the center of said stop, intersects itself any of twice, three times, and four times, and

wherein at least one of said plurality of curved reflecting surfaces has a rotation-asymmetrical shape.

2. An observation apparatus comprising the optical system of claim 1.

3. An optical system according to claim 1, wherein an opening in said stop and the image plane are parallel to each other.

4. An optical system according to claim 1, wherein said stop is provided on the light incidence side of a system comprising a plurality of curved reflecting surfaces.

5. An optical system according to claim 4,

wherein one of said plurality of curved reflecting surfaces which is nearest to said stop is a concave surface.

6. An optical system according to claim 1,

wherein the number of said curved reflecting surfaces is four.

7. An optical system according to claim 6,

wherein said stop is provided on the light incidence side of a system comprising said four curved reflecting surfaces.

8. An optical system according to claim 7,

wherein one of said four curved reflecting surfaces which is nearest to said stop is a concave surface.

9. An optical system according to claim 8, wherein the optical path of the ray is orthogonal to itself at its respective intersecting positions.

10. An optical system according to claim 9,

wherein an opening in said stop and the image plane are parallel to each other.

11. An optical system according to claim 1, wherein each of said plurality of curved reflecting surfaces comprises a rotation-asymmetrical aspherical surface, and the ray of light obliquely impinges thereon.

12. An optical system according to claim 11, wherein said plurality of curved reflecting surfaces are supplied on a transparent member, and the ray of light is successively reflected by said plurality of curved reflecting surfaces while propagating through the interior of said transparent member.

13. An optical system according to claim 12,

wherein both of the light incidence surface and the light emergence surface of said transparent member are curved surfaces.

14. An image pickup apparatus comprising the optical system of claim 1.

29. An optical system according to claim 1 or 15, wherein the optical path intersects itself twice.

30. An optical system according to claim 1 or 15, wherein the optical path intersects itself three times.

31. An optical system according to claim 1 or 15, wherein the optical path intersects itself four times.

15. An optical system comprising:

an optical element which is integrally provided with a plurality of curved reflecting surfaces,

wherein in said optical element, an optical path of a ray of light, successively reflected by said plurality of curved reflecting surfaces, intersects itself any of twice, three times, and four times, and

wherein at least one of said plurality of curved reflecting surfaces has a rotation-asymmetrical shape.

16. An image pickup apparatus comprising the optical system of claim 15.

17. An observation apparatus comprising the optical system of claim 15.

18. An optical system according to claim 15, wherein the direction in which the ray of light enters said optical system and the direction in which the ray of light emerges from said optical system are the same.

19. An optical system according to claim 15, further comprising a stop on the light incidence side of a system comprising said plurality of curved reflecting surfaces.

20. An optical system according to claim 19,

wherein one of said plurality of curved reflecting surfaces which is nearest to said stop is a concave surface.

21. An optical system according to claim 15,

wherein the number of said curved reflecting surfaces is four.

22. An optical system according to claim 21,

wherein said stop is provided on the light incidence side of a system comprising said four curved reflecting surfaces.

23. An optical system according to claim 22,

wherein one of said four curved reflecting surfaces which is nearest to said stop is an concave surface.

24. An optical system according to claim 23, wherein the optical path of the ray of light intersects itself orthogonally at its respective intersecting positions.

25. An optical system according to claim 23,

wherein an opening in said stop and an image plane are parallel to each other.

26. An optical system according to claim 15, wherein each of said plurality of curved reflecting surfaces comprises a rotation-asymmetrical aspherical surface, and the ray of light obliquely impinges thereon.

27. An optical system according to claim 26, wherein said plurality of curved reflecting surfaces are supplied on a transparent member, and the ray of light is successively reflected by said plurality of curved reflecting surfaces while propagating through the interior of said transparent member.

28. An optical system according to claim 27, wherein both of the light incidence surface and the light emergence surface of said transparent member are curved surfaces.