End face observation device

1. An end face observation device comprising:

a first lens including a missing portion extending through in an optical axis direction; a light source configured to generate light that irradiates an end face of an observation target via said first lens;

an image capturing element configured to receive an image of the end face of the observation target via said first lens; and

a structure inserted into the missing portion of said first lens and configured to operate upon the end face of the observation target.

2. An end face observation device according to claim 1 , wherein said structure includes a cleaning mechanism configured to clean the end face of the observation target.

3. An end face observation device according to claim 1 , wherein said light source and said first lens are arranged coaxially.

4. An end face observation device according to claim 1 , wherein said first lens has a ring shape.

5. An end face observation device according to claim 3 , wherein said light source has a ring shape.

6. An end face observation device according to claim 3 , further comprising a tubular case,

wherein said first lens and said structure are arranged at one end of said tubular case,

said light source and said image capturing element are arranged at the other end of said tubular case, and

illumination light from said light source and reflected light from the end face of the observation target propagate through a common space in said case.

7. An end face observation device according to any one of claims 1 , 2 to 6 , further comprising a second lens provided on an optical axis between said first lens and said image capturing element.

8. An end face observation device according to claim 7 , further comprising a transparent member provided on the optical axis between said first lens and said second lens.

9. An end face observation device according to claim 1 , further comprising an optical element provided on an optical axis between said first lens and said image capturing element and configured to partially reflect incident light and partially passes the incident light.

10. An end face observation device according to claim 9 , wherein said optical element comprises one of a beam splitter and a half mirror.

11. An end face observation device according to claim 9 , wherein said optical element comprises a half mirror whose reflecting surface and transmitting surface are nonparallel.

12. An end face observation device according to claim 9 , wherein said optical element comprises a beam splitter, said beam splitter having a transmitting surface facing said light source and a reflecting surface that partially reflects light that enters via the transmitting surface, wherein a relative angle between the transmitting surface and the reflecting surface is not 45° .

13. An end face observation device according to claim 9 , further comprising a second lens provided on an optical axis between said optical element and said image capturing element.

14. An end face observation device according to claim 9 , further comprising a second lens provided on an optical axis between said first lens and said optical element.

15. An end face observation device according to claim 14 , further comprising a third lens provided on the optical axis between said first lens and said second lens.

16. An end face observation device according to claim 9 , further comprising a condensing lens provided on an optical axis between said light source and said optical element.

17. An end face observation device according to claim 9 , further comprising at least one of an iris, a wavelength filter, and a polarization filter on an optical axis between said image capturing element and said optical element.

18. An end face observation device according to claim 9 , further comprising at least one of an iris, a wavelength filter, and a polarization filter on an optical axis between said light source and said optical element.

19. An end face observation device according to any one of claims 9 to 18 further comprising a transparent material provided on the optical axis between said first lens and said optical element.

20. An end face observation device according to any one of claims 9 to 18 , further comprising an operation portion provided on the optical axis between said first lens and said optical element and made of a transparent material,

wherein said operation portion is connected to said structure and is movable in the optical axis direction.

21. An end face observation device according to any one of claims 9 to 18 , wherein said light source and said image capturing element are arranged at respective positions of different optical distances from said optical element.

22. An end face observation device according to any one of claims 9 to 18 , wherein said light source and said image capturing element are arranged at respective positions of an equal optical distance from said optical element.

23. An end face observation device according to any one of claims 9 to 18 , wherein said light source and said image capturing element are arranged at respective positions which are optically conjugate to said first lens.

24. An end face observation device according to any one of claim 1 or 2 , wherein said structure further includes an optical member formed from a transparent member other than air and configured to guide illumination light from said light source to the end face of the observation target.