Optical scanning observation apparatus

• US 7,158,234 B2
• Filed: 03/25/2004
• Issued: 01/02/2007
• Est. Priority Date: 10/31/2001
• Status: Expired due to Fees

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Uchiyama, Akio, Hirata, Tadashi, Horii, Akihiro, Hara, Mitsuhiro, Tokuda, Kazunari, Iizuka, Shuhei, Kumada, Yoshiyuki
• Primary Examiner(s): Toatley, Jr.; Gregory J.
• Assistant Examiner(s): CONNOLLY, PATRICK J
• Application Number:
  US10/808,857
• Publication Number:
  US 20040181148A1
• Time in Patent Office: 1,013 Days
• Field of Search: 356/479, 356/497, 356/511
• US Class Current: 356/479
• CPC Class Codes: A61B 1/0008 characterised by distal tip features
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• 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 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01B 2290/35 Mechanical variable delay line
• CPC Class Codes: G01B 9/02002 using two or more frequencies
• CPC Class Codes: G01B 9/0205 of probe head
• CPC Class Codes: G01B 9/02064 by particular adjustment of coherence gate, i.e. adjusting position of zero path difference in low coherence interferometry
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

Before performing observation with an optical scanning probe using a low-coherence light source and the like, a shutter is inserted in a reference light side optical path to create a state wherein interference light does not occur, in which state a reference member is set to a focal position of a converging optical system such that the output of a light detector is maximal by moving the reference member by a driving device at an observation light optical path side of an optical scanning probe, following which the shutter is opened, and the position of a mirror at the reference light side is moved and set such that the output of the light detecting means is maximal, thereby enabling the optical scanning observation apparatus to be set to a state of suitable optical properties, easily and smoothly.

Claims

1. A scanning observation apparatus comprising:

a low-coherence light source;

light separating means for separating light emitted from the low-coherence light source into an observation light and a reference light;

an observation light optical path for transmitting the observation light;

a reference light optical path for transmitting the reference light;

optical path length variation means provided on at least one of either the observation light optical path or the reference light optical path;

converging means provided at a proximal end of the light separating means;

a light-receiving optical system for photo-reception of light, emitted from the converging means and irradiated on an object of measurement, which has been reflected or scattered;

an observation light return optical path for transmitting light received by the light-receiving optical system;

light joining means for joining the observation light return optical path and the reference light optical path;

light detecting means for converting light from the light joining means into electric signals;

image-forming means for generating an image of the object to be observed from the signals detected by the light detecting means;

display means for displaying an image;

optical scanning means for scanning light on the object to be measured;

light transmission state changing means provided on the reference light optical path, for changing the transmission efficiency of the reference light of the reference light optical path;

a reference member capable of changing a distance from a position where irradiation of light is received from the converging means;

focal position detecting means for determining a position relating to the reference member and the converging means, based on signals detected by the light detecting means, in a state wherein the light transmission state changing means is operated and the transmission efficiency of the reference light optical path is reduced; and

optical path length adjusting means for operating the optical path length variation means based on signals detected by the light detecting means, in a state wherein the light transmission state changing means is operated and interference occurs at the light joining means, such that the optical length of the optical path from the light separating means and passing through the observation light optical path, the converging means, the reference member position determined by the focal position detecting means, the light-receiving optical system, the observation light return optical path, and the light joining means, and that of the reference light optical path, substantially accord.

2. A scanning observation apparatus according to claim 1, wherein signals detected with the light detecting means used by the focal position detecting means are light intensity or contrast information.

3. A scanning observation apparatus according to claim 1, wherein signals detected with the light detecting means used by the optical path length adjusting means are light intensity or detection information.

4. The scanning observation apparatus according to claim 1, further comprising distance changing means for adjusting the position of the reference member in relation to the converging means at a position where the value of the intensity information or the contrast information of light detected with the light detecting means is maximal.

5. The scanning observation apparatus according to claim 4, wherein the optical path length adjusting means are means for adjusting the optical path length variation means such that the value of the intensity information or the contrast information of light detected with the light detecting means is maximal.

6. The scanning observation apparatus according to claim 4, wherein the distance changing means is means for substantially placing in accord a surface position of the reference member and a focal position of the converging means.

7. The scanning observation apparatus according to claim 4, wherein the distance changing means is means for substantially placing in accord a surface position of the reference member for a focal position of the converging means within a depth of field of the converging means.

8. The scanning observation apparatus according to claim 1, wherein, with the optical length of the optical path from the light separating means and passing through the observation light optical path, the converging means, the position relating to the reference member determined by the focal position detecting means, the light-receiving optical system, the observation light return optical path, and the light joining means, as optical path A in a state wherein the light transmission state changing means are operated and interference occurs at the light joining means, the optical path length adjusting means operate the optical path length variation means based on signals detected at the light detecting means, and the difference between the optical path A and the optical length of the reference light optical path is compacted into a range narrower than the longer of a depth of field of the converging means and a coherence length of the low-coherence light source.

9. A scanning observation apparatus according to claim 1, wherein the light transmission state changing means are movable shielding or light reducing means.

10. A scanning observation apparatus according to claim 1, wherein the light transmission state changing means are means for shifting an optical axis of the reference light optical path.

11. A scanning observation apparatus according to claim 1, further comprising a probe portion configured such that the observation light optical path, the converging means, the light-receiving optical system, and at least part of the observation light return optical path, are detachable from the light separating means.

12. A scanning observation apparatus according to claim 1, further comprising a probe wherein at least a part of at least one of the observation light optical path, the converging means, the light-receiving optical system, and the observation light return optical path, is configured of a flexible light transmitting means.

13. A scanning observation apparatus according to claim 11, wherein the probe portion is provided within an endoscope.

14. A scanning observation apparatus according to claim 11, wherein the probe portion is insertable through an endoscope.

15. A scanning observation apparatus according to claim 1, wherein the converging means and the light-receiving optical system are the same.

16. A scanning observation apparatus according to claim 1, wherein the converging means and the light-receiving optical system are the same, and generally form a confocal optical system.

17. The scanning observation apparatus according to claim 1, wherein the reference member is provided on an adjusting jig detachably provided on at least one of either the converging means or the light-receiving optical system.

18. The scanning observation apparatus according to claim 17, wherein the adjusting jig has a distance changing means for changing the distance between the converging means, and the light-receiving optical system and a reflection scattering member.

19. The scanning observation apparatus according to claim 18, wherein the distance changing means is provided with an actuator and is operated with the focal position detecting means.

20. The scanning observation apparatus according to claim 11, wherein the reference member is integrally configured with the probe portion, and comprises a depth scanning means for changing a distance between the reference member and the converging means.

21. The scanning observation apparatus according to claim 20, wherein the depth scanning means is provided with an actuator and is operated with the focal position detecting means.

22. A scanning observation apparatus according to claim 1, wherein the light detecting means have at least two or more outputs.

23. A method for setting a scanning observation apparatus comprising:

providing a low-coherence light source;

providing a light separating means for separating light emitted from the low-coherence light source into an observation light and a reference light;

providing an observation light optical path for transmitting the observation light;

providing a reference light optical path for transmitting the reference light;

providing an optical path length variation means provided on at least one of either the observation light optical path or the reference light optical path;

providing a converging means provided at a proximal end of the light separating means;

providing a light-receiving optical system for photo-reception of light, emitted from the converging means and irradiated on an object of measurement, which has been reflected or scattered;

providing a light joining means for joining an observation light return optical path for transmitting light received by the light-receiving optical system, the observation light return optical path, and the reference light optical path;

providing a light detecting means for converting light from the light joining means into electric signals;

providing an image-forming means for generating an image of the object to be observed from the signals detected by the light detecting means;

providing a display means for displaying an image; and

providing an optical scanning means for scanning light on the object to be measured;

a first step for reducing the transmission efficiency of the reference light optical path;

a second step for making reference to the output of the light detecting means with regard to the reference member, and positioning the reference member near the focal position of the converging means;

a third step for restoring the transmission efficiency of the reference light optical path; and

a fourth step wherein, with an optical length of the optical path from the light separating means and passing through the observation light optical path, the converging means, the reference member position determined by the focus position detecting means, the light-receiving optical system, the observation light return optical path, and the light joining means, as an optical path A in a state wherein positioning of the reference member is determined in the second step, the electric signals detected by the light detecting means are referred to, the optical path variation means are operated, and the optical length of the optical path A and the reference light optical path are substantially in accord.