Optical system for non-flexible endoscopes

• US 5,933,275 A
• Filed: 10/18/1996
• Issued: 08/03/1999
• Est. Priority Date: 10/20/1995
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Igarashi, Tsutomu
• Primary Examiner(s): NGUYEN, THONG Q
• Application Number:
  US08/733,916
• Time in Patent Office: 1,019 Days
• Field of Search: 359/362-363, 359/423, 359/434-435, 359/663, 359/753, 600/130, 600/160, 600/108, 600/171, 600/175, 600/181, 348/65, 348/369, 348/67, 348/337
• US Class Current: 359/435
• CPC Class Codes: G02B 23/2446 of the image relay G02B23/26 takes precedence

Abstract

A relay lens system used in an observation optical system which is to be disposed in an insert section is disclosed. The relay lens system comprises a plurality of relay lens units at least one of which allows longitudinal chromatic aberration to remain in an undercorrected tendency and at least another of which allows longitudinal chromatic aberration to remain in an overcorrected tendency, thereby correcting longitudinal chromatic aberration favorably in the relay lens system as a whole.

Claims

1. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration, and

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element, and

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements,

wherein said at least one relay lens unit which comprises no negative lens element is composed of two biconvex rod-like lens components and biconvex lens components disposed between said biconvex rod-like lens components,

said lens components of said at least one relay lens unit being disposed symmetrically on both front and rear sides of a center of said at least one relay lens unit.

3. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex rod-like lens elements and negative lens elements, and said lens components of said at least another relay lens unit are disposed symmetrically with regard to the center of said at least another relay lens unit in such a direction as to arrange said negative lens elements opposing each other.

4. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex lens elements and negative lens elements disposed on both sides of each rod-like lens element, said lens elements of said at least another relay lens unit being disposed symmetrically with regard to a center of said at least another relay lens unit.

5. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least another relay lens unit which comprises negative lens elements is composed of a positive lens component, a rod-like cemented lens component consisting of a rod-like lens element and negative lens elements disposed on both sides thereof, a rod-like cemented lens component consisting of a rod-like lens element and negative lens elements disposed on both sides thereof, and a positive lens component,

said lens components of said at least another relay lens unit being disposed symmetrically with regard to a center of said at least another relay lens unit.

6. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex rod-like lens elements, positive lens elements and negative lens elements,

said lens elements of said at least another relay lens unit being disposed symmetrically with regard to a center of said relay lens unit.

7. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least another relay lens unit which comprises negative lens elements is composed of a field lens component, a cemented lens component, a cemented lens component and a field lens component,

said lens components being disposed symmetrically with regard to a center of said at least another relay lens unit.

8. An observation optical system for non-flexible endoscopes according to claim 1, wherein said at least another relay lens unit which comprises negative lens elements comprises, in the vicinities of the center of said relay lens unit, at least two negative lens elements made of a glass material having an Abbe'"'"'s number not exceeding 40.

9. An observation optical system for non-flexible endoscopes according to claim 1 or 2, wherein said at least one relay lens unit which comprises no negative lens element comprises an optical element having no power.

2. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration, and

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element, and

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements,

wherein said at least one relay lens unit which comprises no negative lens element is composed of positive field lens components which are disposed in the vicinities of images formed on the front side and the rear side respectively of said relay lens unit, and biconvex lens components disposed in the vicinities of a center of said relay lens unit,

said lens components of said at least one relay lens unit being disposed symmetrically with regard to a center of said at least one relay lens unit.

10. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element,

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements,

wherein said at least one relay lens unit which comprises no negative lens element is composed of two plano-convex rod-like lens components having convex surfaces on sides of the images and biconvex lens components disposed between said plano-convex rod-like lens components, said lens components of said at least one relay lens unit being disposed symmetrically on both front and rear sides of a center of said at least one relay lens unit, and

wherein said at least another relay lens unit which comprises negative lens elements comprises, in the vicinities of the center of said relay lens unit, at least two negative lens elements made of a glass material having an Abbe'"'"'s number not exceeding 40.

11. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element,

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements,

wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex rod-like lens elements and negative lens elements, and said lens components of said at least another relay lens unit are disposed symmetrically with regard to the center of said at least another relay lens unit in such a direction as to arrange said negative lens elements opposing each other.

16. An observation optical system for non-flexible endoscopes according to claim 11, 12, 13, 14 or 15, wherein a number of relay lens units of said plurality of relay lens units which comprise negative lens elements is less than a number of relay lens units of said plurality of relay lens units which comprise no negative lens elements.

17. An observation optical system for non-flexible endoscopes according to claim 11, 12, 13, 14 or 15,

wherein said at least one relay lens unit which comprises no negative lens element is composed of two rod-like lens components which are disposed symmetrically on both front and rear sides of a center of said at least one relay lens unit.

18. An observation optical system for non-flexible endoscopes according to claim 11, 12, 13, 14 or 15,

wherein said at least one relay lens unit which comprises no negative lens element is composed of two piano-convex rod-like lens components having convex surfaces on sides of the images and biconvex lens components disposed between said plano-convex rod-like lens components,

said lens components of said at least one relay lens unit being disposed symmetrically on both front and rear sides of a center of said at least one relay lens unit.

12. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element,

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements, and

wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex lens elements and negative lens elements disposed on both sides of each rod-like lens element, said lens elements of said at least another relay lens unit being disposed symmetrically with regard to a center of said at least another relay lens unit.

13. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element,

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements, and

wherein said at least another relay lens unit which comprises negative lens elements is composed of a positive lens component, a rod-like cemented lens component consisting of a rod-like lens element and negative lens elements disposed on both sides thereof, a rod-like cemented lens component consisting of a rod-like lens element and negative lens elements disposed on both sides thereof, and a positive lens component,

said lens components of said at least another relay lens unit being disposed symmetrically with regard to a center of said at least another relay lens unit.

14. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element,

wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements, and

wherein said at least another relay lens unit which comprises negative lens elements is composed of two rod-like cemented lens components consisting of biconvex rod-like lens elements, positive lens elements and negative lens elements,

said lens elements of said at least another relay lens unit being disposed symmetrically with regard to a center of said relay lens unit.

15. An observation optical system for non-flexible endoscopes which is to be disposed in an elongated insert section of a non-flexible endoscope having said insert section, comprising:

an objective lens system; and

a relay lens system,

wherein said relay lens system comprises a plurality of relay lens units, at least one relay lens unit of said plurality of relay lens units produces undercorrected longitudinal chromatic aberration and at least another relay lens unit of said plurality of relay lens units produces overcorrected longitudinal chromatic aberration,

wherein longitudinal chromatic aberration is corrected in said observation optical system as a whole by cancelling said undercorrected longitudinal chromatic aberration with said overcorrected longitudinal chromatic aberration,

wherein said relay lens system comprises no gradient index lens element,

wherein said at least one relay lens unit which produces undercorrected longitudinal chromatic aberration comprises no negative lens element, wherein said at least another relay lens unit which produces overcorrected longitudinal chromatic aberration comprises negative lens elements, and

wherein said at least another relay lens unit which comprises negative lens elements is composed of a field lens component, a cemented lens component, a cemented lens component and a field lens component,

said lens components being disposed symmetrically with regard to a center of said at least another relay lens unit.