Zoom microscope including an image-acquisition optical path and an observation optical path

1. A microscope comprising:

an objective lens;

an afocal variable-magnification optical system, disposed at an exit side of the objective lens, for variably magnifying the size of an image of the objective lens;

an image-forming optical system, disposed at an exit side of the afocal variable-magnification optical system, for imaging the image of the objective lens;

a splitting member, disposed at an exit side of an image-forming lens, for selectively splitting into an observation optical path or an image-acquisition optical path; and

an observation optical system, disposed in the observation optical path, for visually observing an image split-off from the image-acquisition optical path;

wherein the observation optical path comprises:

a relay optical system for relaying a pupil of the objective lens to a pupil conjugate position;

an optical-path-splitting member, disposed at the object side of the pupil conjugate position for splitting an optical axis of an incident beam into two optical axes for observation by both eyes, one for the left and one for the right; and

an aperture stop, disposed in the observation optical path and disposed at an exit side of the image forming lens, the position of which is toward the object side with respect to the position of the image closest to the observer and is in the vicinity of a conjugate position of the objective lens pupil relayed by the relay optical system, for stopping down a numerical aperture thereof to a numerical aperture smaller than a numerical aperture of the image-acquisition optical path, and

wherein the microscope satisfies the following conditional expression:

D>18 mm

where symbol D represents an exit beam diameter of the afocal variable-magnification optical system.

2. The microscope according to claim 1 , wherein the optical-path-splitting member splits the incident beam into two beams having the same beam diameter by reflection and transmission.

3. The microscope according to claim 1 , further comprising:

an optical-path-splitting member, disposed before the pupil conjugate position in the observation optical path, for splitting the optical path into two, wherein, in the vicinity of each pupil conjugate position in the two optical paths split by the optical-path-splitting member, respective aperture stops are disposed so as to be mutually decentered relative to an optical axis of the observation optical path.

4. The microscope according to claim 3 , wherein the relay optical system comprises:

a plurality of reflecting members disposed in such a manner that the angles thereof can be varied.

5. The microscope according to claim 4 , further comprising:

a recording apparatus for recording the image formed by the image-forming optical system.

6. The microscope according to claim 1 , wherein the following conditional expression is satisfied:

M<200NA

where symbol M represents an overall magnification of an optical system at the observation optical path side of the objective lens, and symbol NA represents an entrance numerical aperture of the objective lens.

7. A microscope according to claim 1 , wherein the variable magnification of the afocal variable-magnification optical system is from 1 to 10.

8. A microscope comprising:

an objective lens;

an afocal variable-magnification optical system, disposed at an exit side of the objective lens, for variably magnifying a size of an image of the objective lens;

an image-forming optical system, disposed at an exit side of the afocal variable-magnification optical system, for imaging the image of the objective lens;

a splitting member, disposed at an exit side of an image-forming lens, for selectively splitting into an observation optical path or an image-acquisition optical path;

an observation optical system, disposed in the observation optical path, for visually observing an image split-off from the image-acquisition optical path;

wherein the observation optical path comprises:

a relay optical system for relaying a pupil of the objective lens to a pupil conjugate position;

an optical-path-splitting member, disposed at the object side of the pupil conjugate position for splitting an optical axis of an incident beam into two optical axes for observation by both eyes, one for the left and one for the right; and

an aperture stop, disposed in the observation optical path and disposed at an exit side of the image forming lens, the position of which is toward the object side with respect to the position of the image closest to the observer and is in the vicinity of a conjugate position of the objective lens pupil relayed by the relay optical system, for stopping down a numerical aperture thereof, wherein the observation aperture stop is configured to stop down the numerical aperture to a numerical aperture smaller than a numerical aperture of the image-acquisition optical path,

wherein the microscope satisfies the following conditional expression:

M<200NA

where symbol M represents an overall magnification of an optical system at the observation optical path side of the objective lens, and symbol NA represents an entrance numerical aperture of the objective lens.

9. The microscope according to claim 8 further comprising:

an optical-path-splitting member, disposed before the pupil conjugate position in the observation optical path, for splitting the optical path into two, wherein, in the vicinity of each pupil conjugate position in the two optical paths split by the optical-path-splitting member, respective observation aperture stops are disposed so as to be mutually decentered relative to the observation optical path.

10. The microscope according to claim 9 , wherein the relay optical system comprises:

a plurality of reflecting members disposed in such a manner that the angles thereof can be varied.

11. The microscope according to claim 8 , further comprising:

a recording apparatus for recording an image focused by the image-acquisition optical system.