Patent ID: 7101072

Claim:
A photoirradiation device which outputs a light beam from an outgoing surface of a lightguide unit, the photoirradiation device comprising: a plurality of point light sources, each point light source being a light-emitting diode; a lightguide unit which has an incident surface and an outgoing surface, the lightguide unit guiding a light beam incident from the incident surface to the outgoing surface; and an optical system which focuses the light beams emitted from the plurality of point light sources on the incident surface of the lightguide unit, wherein the plurality of point light sources are arranged on a surface perpendicular to an optical axis of the optical system, the optical system has a first lens, a second lens, and a third lens, which are arranged in order from the point light sources toward the incident surface of the lightguide unit, an incident surface and an outgoing surfaces in the first lens and the second lens are respectively formed so that a light beam emitted from the point light source arranged near the optical axis is diffused from the optical axis by the first lens and the light beam diffused from the optical axis by the first lens is converted into the light beam substantially parallel to the optical axis, and an incident surface and an outgoing surface of the third lens are formed so that the light beams outgoing from the second lens are focused on the incident surface of the lightguide unit.