Optical system for non-flexible endoscopes

• US 5,852,511 A
• Filed: 09/19/1996
• Issued: 12/22/1998
• Est. Priority Date: 10/20/1993
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Igarashi, Tsutomu, Tateyama, Noriyuki
• Primary Examiner(s): Willis, Davis L.
• Assistant Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US08/718,163
• Time in Patent Office: 824 Days
• Field of Search: 359/362, 359/644, 359/690, 359/689, 359/660, 359/356, 359/359, 359/663, 359/792, 359/708, 359/363, 359/367, 359/432, 359/434, 359/716, 359/717, 348/65, 348/69, 348/70, 348/71, 348/72, 348/73, 348/75
• US Class Current: 359/362
• CPC Class Codes: G02B 23/2446 of the image relay G02B23/26 takes precedence
• CPC Class Codes: G02B 23/2453 of the proximal end

Abstract

In a non-flexible endoscope consisting of an insertion section and an eyepiece section which are separable from each other, an optical system configured so as to correct chromatic aberration produced by an observation optical system disposed in the insertion section with an eyepiece optical system disposed in the eyepiece section. The optical system according to the present invention selects a simple composition for the observation optical system so that it is manufacturable at a low cost and disposable, and is configured so as to have favorable optical performance as a whole by correcting chromatic aberration produced by the observation optical system with the eyepiece optical system.

Claims

1. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed; and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration,

said observation optical system comprises an objective optical system and a relay optical system, and

said eyepiece optical system comprises at least one cemented lens component and satisfies the condition defined below;

space="preserve" listing-type="equation">N.sub.oc ≧

N.sub.R +1

wherein the reference symbol N_oc represents a number of cemented lens components comprised in said eyepiece optical system and the reference symbol N_R designates a number of relay cycle, to be performed by said relay optical system.

2. A non-flexible endoscope according to claim 1, wherein said observation optical system comprises a plurality of lens components each of which is composed of a single lens element.

3. A non-flexible endoscope according to claim 2 wherein all lens elements are made of a plastic material.

4. A non-flexible endoscope according to claim 1, wherein said eyepiece optical system comprises an optical system which forms an intermediate image of the object to be observed in said eyepiece section.

5. A non-flexible endoscope according to claim 1, wherein said relay optical system is composed of lens components each of which consists of a single lens element.

6. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed, and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration,

said insertion section is attachable and detachable to and from said eyepiece section,

said eyepiece optical system comprises an optical system which forms an intermediate image of said object to be observed in said eyepiece section and at least one cemented lens component, and

said observation optical system comprises an objective optical system and a relay optical system, and satisfies the condition defined below;

space="preserve" listing-type="equation">N.sub.oc ≧

N.sub.R +1

wherein the reference symbol N_oc represents a number of cemented lens components comprised in said eyepiece optical system and the reference symbol N_R designates a number of relay cycles to be performed by said relay optical system.

7. A non-flexible endoscope according to claim 6 wherein each of lens components used for composing said objective optical system and said relay optical system is composed of a single lens element.

8. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed, and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration;

said relay optical system is composed of lens components each of which consists of a single lens element,

said observation optical system comprises an objective optical system and a relay optical system,

said relay optical system is composed of unit relay optical systems, each comprising a lens element in the middle of which an image of an object is formed, a lens element in the middle of which a pupil is formed and a lens element in the middle of which an image of the object is formed, and said lens elements are disposed at equal intervals.

9. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed; and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration,

said observation optical system comprises an objective optical system and a relay optical system,

said relay optical system comprises a relay unit which is composed of no more than three singe lens elements each having a positive refractive power, wherein at least one surface of said single lens elements is configured as an aspherical surface, and

said relay unit comprises in order from the object side, a lens element in the middle of which an image of an object is formed, a lens element in the middle of which a pupil is formed and a lens element in the middle of which an image of an object is formed,

each of said lens elements being a positive single lens and being disposed at equal intervals.

10. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed; and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration,

said observation optical system comprises an objective optical system and a relay optical system,

said relay optical system comprises a relay unit which is composed of no more than three single lens elements each having a positive refractive power,

at least one surface of said single lens elements is configured as an aspherical surface,

said relay unit is composed of two lens elements and configured so as to reimage an image of an object formed on a side of incidence of one lens element onto a side of emergence of the other lens element,

said optical system has a pupil between said two lens elements, and

each of said lens elements is a single lens and is disposed between said pupil and said images.

11. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed; and

an eyepiece section which comprises an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system Produces longitudinal chromatic aberration and said eyepiece optical system corrects said chromatic aberration,

said observation optical system comprises an objective optical system and a relay optical system,

said relay optical system comprises a relay unit which is composed of no more than three single lens elements each having a positive refractive power;

at least one surface of said single lens elements is configured as an aspherical surface,

said relay unit is composed of two lens elements and configured so as to reimage an image formed in the middle of one of said lens elements onto the middle of the other lens element,

a pupil is located in the middle of a space between said two lens elements, and

each of said lens elements is a positive single lens and is disposed at equal intervals.

12. A non-flexible endoscope comprising:

an insertion section which comprises an observation optical system for forming an image of an object to be observed and is to be inserted into a cavity to be observed; and

an eyepiece section which comprises, an eyepiece optical system configured so as to be attachable and detachable to and from said insertion section,

wherein said observation optical system produces longitudinal chromatic aberration and said eyepiece optical system corrects ;

aid chromatic aberration,

said observation optical system comprises an objective optical system and a relay optical system,

said relay optical system comprises a relay unit which is composed of no more than three of single lens elements each having a positive refractive power,

at least one surface of said singe lens elements is configured as an aspherical surface; and

said relay unit is composed of only a single bi-convex lens and configured such that an image of said object, said single bi-convex lens and a reimage of the object to be observed are positioned in that order from an object side, and a pupil is located in a middle of said single bi-convex lens.