Patent ID: 7612943

Claim:
An optical device comprising: a first cylindrical lens array in which a plurality of first lens segments each having a semicylindrical or pseudo-semicylindrical shape and having a first radius of curvature and a first width so as to divide laser light into a plurality of light components are arranged; and second lens segments each having a semicylindrical shape or a pseudo-semicylindrical shape and having a second radius of curvature and a second width which are respectively different from the first radius of curvature and the first width, and provided in at least one position of the first cylindrical lens array so as to be interposed between adjacent first lens segments, wherein in the first lens segment, a cross-section shape perpendicular to a longitudinal axis thereof is a wedge-like shape, and a width of an exit section from which transmission light exits is larger than that of an incidence section on which light is incident, and in the second lens segment, a cross-sectional shape perpendicular to a longitudinal axis thereof is a wedge-like shape arranged in the direction reverse to that of the first lens segment, and a width of an exit section from which transmission light exists is smaller than that of an incidence section on which light is incident.