Microscope illumination device

A microscope illumination device, comprising:

• a light source;
• an object lens for illuminating a specimen surface;
• a collector lens for converting diverging light emitted by the light source into parallel light;
• a fly-eye lens placed near to the position of the rear focal point of the collector lens;
• an epi-illumination projection lens for projecting a plurality of light source images generated by the fly-eye lens onto a pupil of the object lens;
• a tube lens for imaging an observation light emitted from the object lens;
• and
• a fluorescence cube placed between the object lens and epi-illumination projection lens and which comprises at least one filter, wherein
• the following conditional expression is satisfied:
• γ2*ffly*D<γ*ffly*φ−h*p,
• where “γ” is defined as the projection magnification ratio of the epi-illumination projection lens, “ffly” as the focal distance, in mm, of the fly-eye lens, “D” as the effective diameter, in mm, of the fly-eye lens, “φ” as the effective diameter, in mm, of the filter comprised in the fluorescence cube, “h” as the distance, in mm, between the filter and the pupil position of the object lens, and “p” as the pitch interval, in mm, between two adjacent elemental lenses of the fly-eye lens.