| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for materializing desirable light distribution precisely in a vehicular lamp.SOLUTION: A projection lens 100 is used for a vehicular lamp. The projection lens 100 includes an incident surface 100a to which light emitted from a light source is made incident, an emission surface 100b from which light made incident from the incident surface 100a is emitted toward the front side of the lamp and which has a convex shape, and a joint surface 100c which joins a marginal part of the incident surface 100a with a marginal part of the emission surface 100b. The joint surface 100c is configured such that (a) a region which is located on a lower part when the projection lens is used for the vehicular lamp is a flat surface 100c1 and (b), when an angle formed between a light beam which is made incident to the incident surface and is refracted and the optical axis is &thetas;1 and an angle formed between a first vector V1 toward the direction separated from the optical axis and a second vector V2 toward the front side of the vehicle containing the optical axis on a flat surface is &thetas;2 in a vertical cross-section containing an optical axis, the relation of &thetas;2>&thetas;1 is satisfied. |
