Abstract: A lens tube of a microscope includes a plurality of observation ports, and first and second optical path switching portions that move relative to each other for switching an optical path to an arbitrary one of the observation ports. The first optical path switching portion can switch for guiding light from a specimen to the second optical path switching portion through a first optical element of the first optical path switching portion, or for guiding the light to the second optical path switching portion iwthout passing through the first optical element. The second optical path switching portion can switch for guiding the light from the first optical path switching portion to an arbitrary one of the observation ports through a second optical element of the second optical path switching portion, or for guiding the light to an arbitrary one of the observation ports without passing through the second optical element.

Abstract: A microscopic illumination apparatus to be applied to a microscope selectively using plural types of objective lenses having different magnifications comprises a light source, a collector lens for making a light flux emitted from the light source a substantially parallel light flux, and at least two fly-eye lenses disposed side by side along the optical axis at the back of the collector lens. A space between the two fly-eye lenses is variable in accordance with an objective lens to be used in the microscope.

Abstract: A lens tube of a microscope comprises a plurality of observation ports, and first and second optical path switching means to be moved relatively to each other for switching an optical path to an arbitrary one of the observation ports upon the relative movement. The first optical path switching means is capable of switching for guiding light from a specimen to the second optical path switching means trough a first optical element owned by the first optical path switching means upon the relative movement or for guiding the light to the second optical path switching means without passing through the first optical element.

Abstract: A microscopic illumination apparatus to be applied to a microscope selectively using plural types of objective lenses having different magnifications comprises a light source, a collector lens for making a light flux emitted from the light source a substantially parallel light flux, and at least two fly-eye lenses disposed side by side along the optical axis at the back of the collector lens. A space between the two fly-eye lenses is variable in accordance with an objective lens to be used in the microscope.