Lighting device for vehicle
A lighting device for a vehicle has a light-emitting element disposed on an optical axis, a first reflection surface for reflecting light emitted from the light-emitting element in an outer radial direction of the optical axis, and a second reflection surface for reflecting the light reflected by the first reflection surface forward. A cross-sectional shape of the first reflection surface taken along a predetermined plane including the optical axis is an ellipse. The ellipse has a light-emitting center as a first focus and an axis line crossing the optical axis as a major axis. The second reflection surface is disposed between the first focus and a second focus of the ellipse. A cross-sectional shape of the second reflection surface taken along the predetermined plane is a parabola having the second focus of the ellipse as a focus and a point located forward of the focus as a vertex.
1. A lighting device for a vehicle, comprising:
a light-emitting element disposed on an optical axis extending in a forward and backward direction of the lighting device;
a first reflection surface for reflecting light emitted from the light-emitting element in an outer radial direction of the optical axis; and
a second reflection surface for reflecting the light emitted from the light-emitting element and reflected by the first reflection surface in the forward direction, wherein
a cross-sectional shape of the first reflection surface taken along a first plane including the optical axis is an ellipse, the ellipse having a light-emitting center of the light-emitting element as a first focus and an axis line crossing the optical axis as a major axis,
the second reflection surface is disposed between the first focus and a second focus of the ellipse,
a cross-sectional shape of the second reflection surface taken along the first plane is a parabola having the second focus of the ellipse as a focus and a point located in the forward direction of the focus as a vertex, and
a cross-sectional shape of the second reflection surface taken along a second plane perpendicular to the optical axis is rectangular.
2. The lighting device according to claim 1 , wherein the first and second reflection surfaces are formed on the surface of a single translucent block.
3. A lighting device for a vehicle, comprising:
a light-emitting element disposed on an optical axis extending in a forward and backward direction of the lighting device;
a first reflection surface for reflecting light emitted from the light-emitting element in an outer radial direction of the optical axis; and
a second reflection surface for reflecting the light emitted from the light-emitting element and reflected by the first reflection surface in the forward direction, wherein
a cross-sectional shape of the first reflection surface taken along a predetermined plane including the optical axis is an ellipse, the ellipse having a light-emitting center of the light-emitting element as a first focus and an axis line crossing the optical axis as a major axis,
the second reflection surface is disposed between the first focus and a second focus of the ellipse,
a cross-sectional shape of the second reflection surface taken along the predetermined plane is a parabola having the second focus of the ellipse as a focus and a point located in the forward direction of the focus as a vertex, and
a cross-sectional shape of the first reflection surface, which is taken along a plane including the major axis of the ellipse and orthogonal to the predetermined plane, is a parabola having the light-emitting center of the light-emitting element as a focus, and the second reflection surface is a parabolic surface, which includes the focus of the parabola and has an axis line orthogonal to the predetermined plane as a focal line.
4. The lighting device according to claim 3 , wherein the first and second reflection surfaces are formed on the surface of a single translucent block.