Alignment method, alignment apparatus, and alignment screen for objective-lens guiding device

1. An alignment method for a guiding device which is attached to an end of an objective lens in such a manner as to be capable of positional adjustment in an optical axis direction and which is brought into contact with an examination target to make a focal position of the objective lens coincident with an examination site, the alignment method comprising:

securing, to an end face of the guiding device, an alignment screen, having a predetermined pattern, at a position which intercepts the optical axis of the objective lens when the guiding device is attached thereto;

relatively moving the objective lens and the guiding device, to which the alignment screen is secured, in the optical axis direction;

fixing relative positions of the objective lens and the guiding device at a position where an in-focus image of the pattern of the alignment screen is obtained, or at a position further relatively shifted by a predetermined distance from that position; and

removing the alignment screen from the guiding device.

2. An alignment method for a guiding device according to claim 1 , wherein the alignment screen is supported on the guiding device, and the guiding device and the objective lens are relatively moved.

3. An alignment method for a guiding device according to claim 1 , wherein the guiding device and the objective lens are moved relatively while measuring a load applied to one of the guiding device and the objective lens.

4. An alignment screen used in the alignment method for a guiding device according to claim 1 , comprising:

a screen main body having a flat surface placed in close contact with the end of the guiding device; and

an attaching-and-detaching portion configured to attach the screen main body to the guiding device in such a manner as to allow attachment thereto and detachment therefrom,

wherein the alignment screen has a predetermined pattern on the flat surface.

5. An alignment screen according to claim 4 , wherein:

the screen main body is formed of a fluorescent material; and

the pattern is formed of indentations provided in the flat surface.

6. An alignment screen according to claim 4 , wherein:

the screen main body is formed of a fluorescent material; and

the pattern is printed on the flat surface.

7. An alignment screen according to claim 4 , wherein:

the screen main body is formed of a fluorescent material; and

the pattern is printed on a transparent sheet covering the flat surface.

8. An alignment screen according to claim 4 wherein:

the screen main body is formed of a non-fluorescent material; and

a pattern of fluorescent material is printed on the flat surface.

9. An alignment screen according to claim 4 , wherein the pattern is formed more finely at a center portion than at edge portions.

10. An alignment apparatus for a guiding device which is attached to an end of an objective lens in such a manner as to be capable of positional adjustment in an optical axis direction and which is brought into contact with an examination target to make a focal position of the objective lens coincident with an examination site, the alignment apparatus comprising:

an objective-lens securing portion configured to secure the objective lens to which the guiding device is attached, so as to be capable of positional adjustment, an alignment screen provided with a prescribed pattern being attached to the guiding device at an end portion thereof;

a visible light source configured to illuminate the alignment screen; and

an image-forming optical system configured to image the pattern passing through the objective lens on a retina of an observer when an end face of the guiding device is coincident with a position corresponding to the examination site.

11. An alignment apparatus for a guiding device according to claim 10 , further comprising:

a relay optical system configured to form an intermediate image of the pattern when the end face of the guiding device is coincident with a position corresponding to the examination site; and

a second screen provided with a second pattern which is located at a position where the intermediate image is formed by the relay optical system.

12. An alignment apparatus for a guiding device which is attached to an end of an objective lens in such a manner as to be capable of positional adjustment in an optical axis direction and which is brought into contact with an examination target to make a focal position of the objective lens coincident with an examination site, the alignment apparatus comprising:

an objective-lens securing portion configured to secure the objective lens, to which the guiding device is attached, so as to enable positional adjustment, an alignment screen provided with a prescribed pattern being attached to the guiding device at an end portion thereof;

a visible light source configured to illuminate the alignment screen;

an image-acquisition device to image the pattern passing through the objective lens; and an image-forming optical system configured to image the pattern passing through the objective lens on the image-acquisition device when an end face of the guiding device is coincident with a position corresponding to the examination site.