A light guide extending in a main direction and including an inlet face for the light emitted by a light source, the inlet face being contoured to form a collimator. The light guide includes a face for guiding the light, a light outlet face, and a face for decoupling the light towards the outlet face, the decoupling face being transversely opposite to the outlet face. At least one portion of the profile of the inlet face is constant in a transverse direction so as not to collimate the light in a longitudinal plane including the transverse direction but in a longitudinal plane perpendicular to the transverse direction.

A light guide extending in a main direction and including an inlet face for the light emitted by a light source, the inlet face being contoured to form a collimator. The light guide includes a face for guiding the light, a light outlet face, and a face for decoupling the light towards the outlet face, the decoupling face being transversely opposite to the outlet face. At least one portion of the profile of the inlet face is constant in a transverse direction so as not to collimate the light in a longitudinal plane including the transverse direction but in a longitudinal plane perpendicular to the transverse direction.

A light guide is provided for a lighting device of a vehicle. The light guide includes an entrance surface into which light can enter, at least one lateral exit surface from which a portion of the light that has entered can exit, an end region through which a portion of the light that has entered can exit. The end region is structured and/or shaped in such a way that a portion of light which laterally emerges from the region adjacent to the end region after reflection at or in the end region is reduced or minimised.

A vehicular lighting tool of the present invention includes light source and light guide lens, the light guide lens has introduction section into which light is introduced, light distribution section that emits introduced light as illumination light, decoration section that emits introduced light as decoration light, and slit section that separates introduction section and decoration section, and introduction section has light incidence surface into which light from light source enters, lens cut that emits portion of light from light source and that causes portion of light to enter decoration section via slit section, first inclined surface located closer to light distribution section than lens cut, second inclined surface that connects first inclined surface and decoration section, and reflection cut surface provided on surface opposite to slit section and that reflects portion of light entering from light incidence surface so as to advance along second inclined surface.

A lamp device suppresses attenuation and reflection of a radar wave attributable to a light guide body, does not change an electromagnetic wave radiation pattern, and does not impair a radar function. The lamp device includes: a light guide body covering a part of an electromagnetic wave radiation surface of a radar device; and a light source, wherein, when the thickness of the light guide body is denoted by TG, and the wavelength of a radiated electromagnetic wave from the radar device in the light guide body is denoted by λd, TG is set such that TG<λd/2 is satisfied when the reflection loss of the light guide body with respect to the radiated electromagnetic wave is below a transmission loss, and a reflection loss is −10 dB or less when the reflection loss is equal to or more than a transmission loss.

A lamp device suppresses attenuation and reflection of a radar wave attributable to a light guide body, does not change an electromagnetic wave radiation pattern, and does not impair a radar function. The lamp device includes: a light guide body covering a part of an electromagnetic wave radiation surface of a radar device; and a light source, wherein, when the thickness of the light guide body is denoted by TG, and the wavelength of a radiated electromagnetic wave from the radar device in the light guide body is denoted by λd, TG is set such that TG<λd/2 is satisfied when the reflection loss of the light guide body with respect to the radiated electromagnetic wave is below a transmission loss, and a reflection loss is −10 dB or less when the reflection loss is equal to or more than a transmission loss.

A vehicle lighting device including a light source configured to emit diverging light a fiber bundle including a plurality of optical fibers bundled into a cross sectional shape configured to be optically coupled to the light source; and a coupling device configured to optically couple the light source to the fiber bundle, the coupling device including a reflecting portion configured to reflect the diverging light toward the optical fiber bundle and a blocking portion configured to block light from bleeding from the assembly.

A vehicular lighting tool of the present invention includes light source and light guide lens, the light guide lens has introduction section into which light is introduced, light distribution section that emits introduced light as illumination light, decoration section that emits introduced light as decoration light, and slit section that separates introduction section and decoration section, and introduction section has light incidence surface into which light from light source enters, lens cut that emits portion of light from light source and that causes portion of light to enter decoration section via slit section, first inclined surface located closer to light distribution section than lens cut, second inclined surface that connects first inclined surface and decoration section, and reflection cut surface provided on surface opposite to slit section and that reflects portion of light entering from light incidence surface so as to advance along second inclined surface.

Provided is a light source device, including: a light-emitting chip arranged on a base plate and configured to emit first light; a light guide rod including first and second light guide portions, the first light guide portion including a light incident end surface, the first light entering the light guide rod through the light incident end surface and being transmitted to the second light guide portion after passing through the first light guide portion, and the second light guide portion including a light-outputting surface for outputting light; a first positioning member including a first groove for accommodating the light guide rod, being directly or indirectly fixed relative to the base plate; and a movable fixing assembly configured to fix, together with the groove of the first positioning member, the light guide rod along a radial direction of the light guide rod, and deforms when fixing the light guide rod.

Provided is a light source device, including: a light-emitting chip arranged on a base plate and configured to emit first light; a light guide rod including first and second light guide portions, the first light guide portion including a light incident end surface, the first light entering the light guide rod through the light incident end surface and being transmitted to the second light guide portion after passing through the first light guide portion, and the second light guide portion including a light-outputting surface for outputting light; a first positioning member including a first groove for accommodating the light guide rod, being directly or indirectly fixed relative to the base plate; and a movable fixing assembly configured to fix, together with the groove of the first positioning member, the light guide rod along a radial direction of the light guide rod, and deforms when fixing the light guide rod.