Patent ID: 8100561

Claim:
A light source unit, comprising: a light source element; an optical-waveguide-formed element in which an optical waveguide is formed; a prism for turning back a light flux emitted from the light source and guiding the light flux toward an incident end of the optical waveguide, wherein the light flux forms an optical path along a first optical axis extending from the light source element, a second optical axis extending toward the optical-waveguide-formed element, and a third optical axis connecting the first and second optical axes, the prism comprising a surface with refractive power which forms a coupling optical system for coupling the light flux emitted from the light source onto the optical waveguide; and an actuator for moving the prism comprising the surface with the refractive power, wherein the actuator has an elongated shape and is arranged such that an elongated direction of the actuator and a direction where the actuator moves the prism coincide with the third optical axis.