Optical element having a plurality of decentered reflecting curved surfaces, and optical instrument including the same

• US 5,995,287 A
• Filed: 09/19/1996
• Issued: 11/30/1999
• Est. Priority Date: 09/27/1995
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sekita, Makoto
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US08/707,486
• Time in Patent Office: 1,167 Days
• Field of Search: 359/599, 359/839, 359/856, 359/857, 359/859, 359/884, 359/364, 359/365, 359/726, 359/727, 359/267, 359/629, 359/630, 359/631, 359/634, 359/834, 385/119
• US Class Current: 359/599
• 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 integrally formed optical element includes an incident surface into which light flux from an object enters, a plurality of reflecting curved surfaces decentered one to the other from which the light flux entered from the incident surface is reflected and an emergent surface from which the light flux from the reflecting curved surfaces is emitted, wherein an antireflection film is applied onto the incident surface and the emergent surface, and wherein the light flux emitted from the emergent surface forms an image.

Claims

1. An integrally formed optical element, comprising:

an incident surface into which light flux from an object enters;

a plurality of reflecting curved surfaces decentered one to the other from which the light flux entered from said incident surface is reflected, at least one of said plurality of reflecting curved surfaces being formed into a rotationally asymmetrical aspheric shape, wherein said shape has only one plane of symmetry; and

an emergent surface from which the light flux from said plurality of reflecting curved surfaces is emitted,

wherein an antireflection film is applied onto at least one of said incident surface and said emergent surface, and

wherein the light flux emitted from said emergent surface forms an image.

2. An optical element according to claim 1, said plurality of reflecting curved surfaces having a reflecting film formed thereon, wherein a range of formation of said reflecting film is substantially equal to a range in which an effective light flux from the object enters.

3. An optical element according to claim 2, said plurality of reflecting curved surfaces having diffusing surfaces formed on the portions thereof other than the range of formation of said reflecting film.

4. An optical element according to claim 2, said plurality of reflecting curved surfaces having a reflection protective layer formed on said reflecting film.

5. An optical element according to claim 4, wherein a color of said reflection protective layer is black.

12. An optical element according to claim 1, wherein an antireflection film is applied onto said incident surface and an antireflection film is applied onto said emergent surface.

6. An optical instrument comprising an integrally formed optical element, said optical element comprising:

an incident surface into which light flux from an object enters;

a plurality of reflecting curved surfaces decentered one to the other from which the light flux entered from said incident surface is reflected, at least one of said plurality of reflecting curved surfaces being formed into a rotationally asymmetrical aspheric shape, wherein said shape has only one plane of symmetry; and

an emergent surface from which the light flux from said plurality of reflecting curved surfaces is emitted,

wherein an antireflection film is applied onto at least one of said incident surface and said emergent surface, and

wherein the light flux emitted from said emergent surface forms an image.

7. An optical instrument according to claim 6, said plurality of reflecting curved surfaces having a reflecting film formed thereon, and

wherein a range of formation of said reflecting film is substantially equal to a range in which an effective light flux from the object enters.

8. An optical instrument according to claim 7, said plurality of reflecting curved surfaces having diffusing surfaces formed on the portions thereof other than the range of formation of said reflecting film.

9. An optical instrument according to claim 7, said plurality of reflecting curved surfaces having a reflection protective layer formed on said reflecting film.

10. An optical instrument according to claim 9, wherein a color of said reflection protective layer is black.

11. An optical instrument according to claim 6, further comprising an image pick-up means for picking-up an image formed by said optical element.

13. An optical instrument according to claim 6, wherein an antireflection film is applied onto said incident surface and an antireflection film is applied onto said emergent surface.