Microscope switchable between bright-field observation and fluorescence observation having movable lens

1. A microscope that switches an observation method between bright-field observation and fluorescence observation, comprising:

an objective, to be used for the bright-field observation and the fluorescence observation, that irradiates a sample with excitation light and converts fluorescence from the sample into a parallel light flux;

a beam splitter that splits the fluorescence and the excitation light from each other;

a collective lens that is arranged in such a manner that the collective lens is freely set in and removed from an optical path between the beam splitter and the objective, that has positive power for collecting the parallel light flux from the objective, and that is set in the optical path for fluorescence observation relying on the objective and is removed from the optical path for bright-field observation relying on the objective;

a scanner that scans the sample with the excitation light;

a photodetector that detects the fluorescence generated at the sample; and

a pupil relay optical system that projects a pupil of the objective into the photodetector and that includes the collective lens and an optical system arranged between the beam splitter and the photodetector.

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

a tube lens that forms a bright-field observation image,

wherein the tube lens is arranged at a position, on an optical path that has branched from an optical path of the excitation light and an optical path of the fluorescence, on which light that has been converted by the objective into a parallel light flux is incident for bright-field observation.

3. The microscope according to claim 1 , wherein:

the beam splitter is arranged in such a manner that the beam splitter is freely set in and removed from an optical path, and

the microscope further includes a mechanism that coordinates setting and removal of the collective lens and setting and removal of the beam splitter.

4. The microscope according to claim 3 , wherein the mechanism is a fluorescence cube turret.

5. The microscope according claim 1 , wherein the collective lens is arranged in such a manner that the collective lens is freely set in and removed from the optical path independently from a different component.

6. The microscope according to claim 1 , wherein the beam splitter is a dichroic mirror.

7. A microscope that switches an observation method between bright-field observation and fluorescence observation, comprising:

an objective, to be used for the bright-field observation and the fluorescence observation, that irradiates a sample with excitation light and converts fluorescence from the sample into a parallel light flux;

a beam splitter that splits the fluorescence and the excitation light from each other;

a collective lens that is arranged in such a manner that the collective lens is freely set in and removed from an optical path between the beam splitter and the objective, that has positive power for collecting the parallel light flux from the objective, and that is set in the optical path for fluorescence observation relying on the objective and is removed from the optical path for bright-field observation relying on the objective;

a scanner that scans the sample with the excitation light;

a photodetector that detects the fluorescence generated at the sample;

a pupil relay optical system that projects a pupil of the objective into the photodetector and that includes the collective lens and an optical system arranged between the beam splitter and the photodetector;

a tube lens that forms a bright-field observation image; and

a mechanism that coordinates setting and removal of the collective lens and setting and removal of the beam splitter,

wherein the tube lens is arranged at a position, on an optical path that has branched from an optical path of the excitation light and an optical path of the fluorescence, on which light that has been converted by the objective into a parallel light flux is incident for bright-field observation, and

wherein the beam splitter is arranged in such a manner that the beam splitter is freely set in and removed from an optical path.