Endoscope system

• US 6,527,708 B1
• Filed: 06/29/2000
• Issued: 03/04/2003
• Est. Priority Date: 07/02/1999
• Status: Expired due to Fees

• Current Assignee: Pentax Corporation (Hoya Corporation)
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Nakamura, Tetsuya, Eguchi, Masaru, Okada, Shinsuke, Furusawa, Koichi, Ozawa, Ryo, Utsui, Tetsuya
• Primary Examiner(s): Pothier, Denise M.
• Application Number:
  US09/605,852
• Time in Patent Office: 978 Days
• Field of Search: 600/160, 600/109, 600/118, 600/173, 600/178, 600/181-182
• US Class Current: 600/160
• CPC Class Codes: A61B 1/0005 combining images e.g. side-by-side, superimposed or tiled
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00179 for off-axis viewing
• CPC Class Codes: A61B 1/0623 for off-axis illumination
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

An endoscope system capable of obtaining a normal light image and/or fluorescent light image is further provided with an a low-coherent light source arranged on a proximal end side of one of first and second light guides. A scanning unit is provided to cause the low-coherent light beam emerged from a tip of the first light guide to scan on the object. The low-coherent light reflected by the object is directed to the first light guide by the scanning unit as detecting light. A mirror is provided to reflect the low-coherent light beam emerged from a tip of the second light guide. A detector is arranged on a proximal end side of the other of the first and second light guides to detect interference fringe pattern generated by interference between the detecting light and the reference light. By changing a length of an optical path, via the first light guide, from the coupler to the object relative to a length, via the second light guide, of an optical path from the coupler to the mirror, a tomogram of the object can be captured.

Claims

1. An endoscope system, comprising:

an illuminating optical system that emits at least one of visible light and excitation light for illuminating an object to be observed, the excitation light causing biotissues to fluoresce;

an objective optical system that converges light from the object to form an optical image of the object;

an insertion tube comprising;

a) a cylindrical portion;

b) a flatter portion formed at a tip of said cylindrical portion;

c) an inclined surface configured to connect respective side surfaces of said cylindrical portion and said flatter portion;

d) a scanning window on a surface of said flatter portion, said scanning window located out of a field of view of said objective optical system, said scanning window configured to face an object that is located within the field of view of said objective optical system;

an image capturing system that captures the optical image formed by said objective optical system;

a first light guide;

a second light guide;

a coupler, said first and second light guides being optically coupled by said coupler;

a low-coherent light source arranged on a proximal end side of one of said first and second light guides, a low-coherent light beam emitted by said low-coherent light source being incident on said one of said first and second light guides;

a scanning unit configured to cause the low-coherent light beam emerged from a tip of said first light guide, to scan on the object, the low-coherent light reflected by the object being directed to said first light guide by said scanning unit as detecting light, said scanning unit further configured to emit said low-coherent light beam through said scanning window;

a mirror that reflects the low-coherent light beam emerged from a tip of said second light guide so as to impinge on the tip of said second light guide as reference light;

an optical path length adjusting system that changes a length of an optical path from said coupler to the object via said first light guide relative to a length of an optical path from said coupler to said mirror via said second light guide;

a detector arranged on a proximal end side of the other of said first and second light guides, said detector detecting interference fringe generated by interference between the detecting light and the reference light and outputs an electrical signal; and

a signal processing system that captures a tomogram of the object based on the signal that is output by said detector when the optical path length adjusting system and said scanning unit operate;

wherein;

said illuminating optical system comprises an illuminating lens that is fixed on said inclined surface and is configured to emit light toward the object, and

said objective optical system includes an objective lens that is fixed on said inclined surface and is configured to receive the light from the object.

2. The endoscope system according to claim 1, said optical path length adjusting system varies the length of the optical path from said coupler to the object via said first light guide relative to the length of the optical path from said coupler to said mirror via said second light guide by moving said mirror in a direction parallel to the central axis of the tip of said second light guide.

3. The endoscope system according to claim 1, wherein said signal processing system forms a tomogram of the object based on the signal output by said detector when said optical path length adjusting system periodically varies the length of the optical path from said coupler to the object via said first light guide relative to the length of the optical path from said coupler to said mirror via said second light guide, and when said scanning unit operates.

4. The endoscope system according to claim 1, wherein said signal processing system forms a tomogram when said optical path length adjusting system sequentially varies the length of the optical path from said coupler to the object via said first light guide relative to the length of the optical path from said coupler to said mirror via said second light guide for each scanning position.

5. The endoscope system according to claim 1, further comprising:

a visible light source;

an excitation light source;

a light source switching system that selectively introduces the light emitted by said visible light source and said excitation light source to said illuminating optical system,

wherein said objective optical system forms a normal light image of the object when the visible light is introduced to said illuminating optical system, and

wherein said objective optical system forms a fluorescent light image of the object when the excitation light is introduced to said illuminating optical system.

6. The endoscope system according to claim 1, wherein said low-coherent light source includes a super high intensity light emitting diode.

7. The endoscope system according to claim 1, further comprising a display system for displaying an image of the surface of the object captured by said image capturing system and the tomogram of the object obtained by said signal processing system.

8. The endoscope system according to claim 1, said optical path length adjusting system varies the length of the optical path from said coupler to the object via said first light guide relative to the length of the optical path from said coupler to said mirror via said second light guide by moving said mirror in a direction parallel to the central axis of the tip of said second light guide.

9. The endoscope system according to claim 1, further comprising:

a visible light source;

an excitation light source;

a light source switching system that selectively introduces the light emitted by said visible light source and said excitation light source to said illuminating optical system,

wherein said objective optical system forms a normal light image of the object when the visible light is introduced to said illuminating optical system, and

wherein said objective optical system forms a fluorescent light image of the object when the excitation light is introduced to said illuminating optical system.

10. The endoscope system according to claim 1, further comprising a display system for displaying an image of the surface of the object captured by said image capturing system and the tomogram of the object obtained by said signal processing system.