The invention provides a light source unit using a liquid core fiber as a light guide, by which the liquid core fiber is inhibited from being overheated, and a light source unit by which an infrared cut filter having a multi-layer reflection film can prevent infrared rays from being introduced into a liquid core fiber, and its miniaturization can be made without causing evils.
The first light source is equipped with a light source having a discharge lamp and a converging mirror, and a light guide formed of a liquid core fiber, wherein the light source and the light guide are held in a casing made of a metal, an infrared cut filter is provided in a cylindrical light shielding body surrounding an optical path in the interior of the casing, and the light shielding body and the light guide holding portion are thermally insulated from each other by a heat insulating material portion.
The second light source unit is equipped with a light source having a discharge lamp and a concave mirror projecting parallel light or substantially parallel light, and a light guide formed of a liquid core fiber, wherein an infrared cut filter having an infrared reflecting layer formed of a multi-layer reflection film is provided on an optical path, and a condenser lens is provided at a more forward position than the infrared cut filter.