Vehicle lighting device having light transmitting member with annular mirror-finish

A vehicle lighting device comprising:

• a light emitting element that is arranged in vicinity of a predetermined point on an optical axis extending in forward and backward directions of the lighting device and that directs in a forward direction of the lighting device;
• and
• a light transmitting member arranged on a front side of the lighting device relative to the light emitting element,
• wherein light emitted from the light emitting element enters the light transmitting member, the light which enters the light transmitting member is reflected by an internal reflection on a front surface of the light transmitting member, is subsequently reflected by an internal reflection on a rear surface of the light transmitting member, and exits the front surface of the light transmitting member after being reflected by the internal reflection on the rear surface of the light transmitting member,
• wherein the front surface of the light transmitting member comprises a planar surface perpendicular to the optical axis,
• wherein the rear surface of the light transmitting member is composed of a predetermined light reflection controlling surface formed by adopting, as a reference surface, a paraboloid of revolution having a focal point at a position of plane symmetry with the predetermined point with respect to the front surface of the light transmitting member,
• wherein an annular region having a center at the optical axis in the front surface of the light transmitting member is mirror-finished,
• wherein an outer peripheral edge of the annular region is positioned in a vicinity of a position where an incident angle of the light emitted from the light emitting element to the front surface of the light transmitting member is equal to a critical angle, and
• wherein an inner peripheral edge of the annular region is set in a vicinity of a position where the light which has exited the light emitting element and reflected by the internal reflection on the front surface of the light transmitting member enters a position immediately behind the outer peripheral edge of the annular region in the rear surface of the light transmitting member.