Patent ID: 8646919

Claim:
A light source unit comprising: a light emitting plate which has a plurality of segment areas, wherein the light emitting plate includes a luminescent material which emits light having a predetermined wavelength band by receiving excitation light, and wherein a rotation of the light emitting plate is controllable; a primary light source for emitting the excitation light onto the luminescent material; a secondary light source for emitting light having a wavelength band which differs from wavelength bands of the luminescent light emitted from the luminescent material and the excitation light emitted from the primary light source; a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to a same optical path; and a light source controller for controlling emission of light from the primary light source and the secondary light source; wherein: the light emitting plate has a fan-shaped area which defines a primary light source turning-off range controlled by the light source controller, the fan-shaped area having an acute center angle centered at a boundary line between two segment areas within the plurality of segment areas, and the fan-shaped area being set to be wider than a size of an incident plane of a light mixing unit to which light is guided via the light guiding optical system; and the light source controller is configured to perform control to turn off the primary light source when either one of lines which define boundaries of the fan-shaped area comes to be positioned at a center of a substantially circular illumination area of the light from the primary light source.