Patent ID: 8308306

Claim:
A light source unit comprising: a light emitting plate which has a plurality of segment areas and in which a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light and a transmissive portion which transmits light are formed respectively on at least the plurality of segment areas; a primary light source for emitting the excitation light onto the luminescent material layer; 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 layer 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 the 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 primary light source is a laser emitter which emits laser light having a wavelength band of blue; the luminescent material layer comprises a luminescent material which emits at least light having a wavelength band of green by receiving the excitation light; the light emitting plate is a luminescent wheel which comprises a base material whose rotation can be controlled; the light source controller is configured to perform control to turn off the primary light source and to perform control to turn on the secondary light source so as to prevent the light from the primary light source from being emitted onto at least one boundary of the segment areas which are adjacent to each other; the base material has two segment areas which are adjacent to each other, the luminescent material layer is formed on one of the segment areas, and the other segment area comprises the transmissive portion; the light source controller is configured to perform control to turn off the primary light source and to perform control to turn on the secondary light source at a position where an illumination area stretches over the two segment areas so that the light source controller prevents a combination of wavelength bands of two colors from being emitted from the light emitting plate by emission of the light from the primary light source onto at least one boundary of the two segment areas; and a primary light source turning-off range controlled by the light source controller is a fan-shaped area whose center angle centered at a boundary line between the two segment areas is an acute angle, and the primary light source is turned off when either one of lines which connect a center of the luminescent wheel and tangents to an outer circumference of a substantially circular illumination area of the light from the primary light source comes to be positioned at the boundary of the two segment areas.