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

• US 6,181,470 B1
• Filed: 07/19/1999
• Issued: 01/30/2001
• 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): Sikder, Mohammad Y.
• Application Number:
  US09/356,463
• Time in Patent Office: 561 Days
• Field of Search: 359/364, 359/365, 359/366, 359/726, 359/267
• US Class Current: 359/364
• 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 optical element of transparent optical material, said optical element comprising:

an incident surface into which light enters;

a plurality of reflecting surfaces on which the light entered from said incident surface is reflected in order; and

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

wherein at least one of said incident surface and said emergent surface is coated with an antireflection film, and

at least one surface of said incident surface, said plurality of reflecting surfaces, and said emergent surface is a rotationally asymmetric aspherical surface having only one plane of symmetry.

2. An optical element according to claim 1, said optical element having positive power as a whole.

3. An image pick-up device comprising:

(1) a photographicing optical system having an optical element of transparent optical material, said optical element comprising;

(a) an incident surface into which light enters;

(b) a plurality of reflecting surfaces on which the light entered from said incident surface is reflected in order; and

(c) an emergent surface from which the light reflected from said plurality of reflecting surfaces is emmitted,

wherein at least one of said incident surface and said emergent surface is coated with an antireflection film, and

wherein at least one surface of said incident surface, said plurality of reflecting surfaces, and said emergent surface is a rotationally asymmetric aspherical surface having only one plane of symmetry, and

(2) an image pick-up device for receiving an image formed by said photographing optical system.

4. An image pick-up device according to claim 3, wherein said optical element has a positive power as a whole.