HEADLIGHT DEVICE FOR VEHICLES AND LIGHT GUIDE ELEMENT

摘要

The present invention provides a small-sized headlight device for vehicles, which is capable of achieving a desired light distribution pattern. This headlight device (100) for vehicles is provided with: a light source (10) that emits light; a light guide element (20), wherein light emitted from the light source (10) is incident on a light incident surface (21) and the incident light is guided therein and discharged from a light exit surface (22); and an illumination optical system (30) which illuminates the area in front of a vehicle with the light discharged from the light exit surface (22). The light guide element (20) has: a first light guide part (1) that extends from the light incident surface (21) to the light exit surface (22) and guides the incident light; and a second light guide part (2) that extends from the light incident surface (21) to the light exit surface (22), while being in contact with the first light guide part (1), and guides the incident light. The first light guide part (1) and the second light guide part (2) have different refractive indexes from each other. The light guide element (20) is configured such that some of the light incident on the first light guide part (1) is able to be incident on the second light guide part (2).