Prism lens, light deflection device, and LiDAR apparatus

A light deflection device, comprising:

• a prism lens;
• and
• a waveguide having a diffraction grating formed by periodically arranging a low-refractive-index region on a high-refractive-index member,
• wherein the prism lens comprises:
• a prism lens body having a set of facing planes a mutual distance of which decreases or increases from one end to another end;
• and
• two cylindrical lenses integral to the set of facing planes,
• wherein the prism lens is configured such that light radiated from the waveguide enters from one facing plane of the set of facing planes and exits from another facing plane of the set of facing planes,
• wherein the prism lens body is formed such that a distance between the set of facing planes is shorter toward a downstream side of the direction of incidence of light to the waveguide, and
• wherein each of the two cylindrical lenses is formed such that, for a first cylindrical lens of the two cylindrical lenses, a cross section shape thereof at a first plane perpendicular to a direction of a slope of the one facing plane of the prism lens body having the first cylindrical lens thereon with respect to the other facing plane of the set of facing planes has a certain curved shape to be convex against the one facing plane having the first cylindrical lens thereon, and for a second cylindrical lens of the two cylindrical lenses, a cross section shape thereof at a second plane perpendicular to a direction of a slope of the other facing plane of the prism lens body having the second cylindrical lens thereon with respect to the one facing plane of the set of facing planes has a certain curved shape to be convex against the other facing plane having the second cylindrical lens thereon.