Patent ID: 7245426

Claim:
A fluorescence microscope comprising: an objective provided below a sample, with oil provided between the objective and sample; a laser beam source which emits a laser beam; an optical fiber which transmits the laser beam from the laser beam source; a fiber lead-in portion provided at an optical fiber outgoing portion of the optical fiber; a fiber projection tube including a collimator lens which collimates the laser beam emitted from the optical fiber outgoing portion of the optical fiber; a movement portion which holds the optical fiber outgoing portion; a screw hole with which the movement portion is engaged; a compression coil spring configured to press an outer side surface portion of the movement portion in a direction along a movement path of the movement portion; a slant surface contact portion provided at an outer side surface of the movement portion opposite to the outer side surface portion; a micrometer holding portion fixed to the fiber lead-in portion; a micrometer including a rotation portion held at the micrometer holding portion and a knob which is provided at the rotation portion; a capsule adapter which is provided at an end of the rotation portion of the micrometer, and which is adapted to be brought into contact with the slant surface contact portion; an incident light projection tube which is operable to select one of the laser beam and a mercury light beam emitted from a mercury burner as a beam to be applied to the sample, and which comprises a high-reflection mirror to reflect one of the laser beam and the mercury light beam; a condensing lens which is provided at the incident light projection tube to guide the selected one of the laser beam and the mercury light beam to a mirror unit turret; a dichroic mirror which is provided in the mirror unit turret to guide at least the laser beam from the condensing lens to the objective; and a stopping mechanism for the micrometer which prevents an optical axis of the optical fiber outgoing portion from coinciding with an optical axis of the fiber projection tube, said stopping mechanism being located away from the optical axis of the fiber projection tube; wherein the optical axis of the optical fiber outgoing portion is stopped by the micrometer at a position which is located away from the optical axis of the fiber projection tube and at which an incidence angle of the laser beam on a surface of the sample is slightly larger than a critical angle.