| 摘要 |
PURPOSE: To obtain a light value provided by law even if a power input is reduced by a method wherein a light emitting diode is oriented into a backward direction against a running direction and, in cooperation with an optical mirror unit, parts of a light from the optical mirror unit are emitted into sidewise directions and a part of the light is emitted into an upward direction. CONSTITUTION: An optical mirror unit has gate-shaped surfaces 13 with parabolic generating line 14 and parallel envelope line 15 warped into annular forms on both its sides. Parts of a light from a light emitting diode 12 oriented in an upward direction are reflected into solid angles on both the sides by the gate-shaped surfaces 13. The other part of the light reaches an upward zone in a solid angle through a gap 16 between the gate-shaped surfaces 13. In order to obtain a conical light developed upward into a fan-shape, the optical mirror unit has surfaces 17 facing the gap 16 which are formed as convex cylindrical mirror surfaces. By the surfaces 17, the light emitted from the diode is reflected so as to form a conical light with an opening angle conforming to a law as a whole. |
