Lighting device and traveling body using same
AssigneePanasonic Intellectual Property Management Co., Ltd.
InventorsAtsushi Fukui, Koichiro Ono, Tatsuo Dohi
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Abstract
There is provided a lighting device capable of forming a line beam having a sufficiently long length in an irradiation direction. A distance between a light source end close to irradiation surface and irradiation surface is greater than a distance between lens center and irradiation surface by using light source in which a plurality of light emitters is arranged in a straight line and lens of which an emission surface having a constant curvature is corrected by an odd function. Accordingly, a shape of light source is formed on irradiation surface, and thus, it is possible to form line beam having the sufficiently long length in the irradiation direction.
Claims7
A lighting device that forms a line beam on a road surface, the lighting device comprising:
- a light source that includes a plurality of light emitters arranged in a line;
- and
- a lens that is disposed in a direction in which light is emitted from the light source, and in which at least one of an incident surface and an emission surface is a curved surface,
- wherein a contour shape of the emission surface is a shape represented by a cubic function defined around a center of the lens and having a single real root added to a curve having a constant curvature,
- the light emitted from the light source is refracted by the lens to be incident on the road surface to form the line beam,
- the light emitters form an elongated straight line shape which is arranged perpendicular to the road surface, and
- a distance between the road surface and an end of the elongated straight line shape formed by the light emitters closest to the road surface is greater than a distance between the road surface and the center of the lens.
Dependencies are inferred from the claim text.