| 摘要 |
PURPOSE:To improve the directivity of a light source, by arranging the light source so that the emitted light is made incident to the edge face of a hollow and columnar transparent matter. CONSTITUTION:The beam made incident to a hollow part through an edge face formed into a rotary hyperboloid or a spherical surface is radiated directly or after a full-reflection on the inner surface through a pipe in the same angle as the angle of radiation of a light emitting diode 6. In the case of a material having a 1.5 refractive index, the beam made incident with 5 deg. to the optical axis has a >=60% full- reflection. The full-reflection quantity increases as the angle decreases. The optical path having a >=psim radiation angle causes refraction by a curved surface and becomes parallel to the optical axis. A rotary hyperboloid is ideal for the curved surface, but a spherical surface is also available if some problem of production arises although some inferiority in its characteristics may be caused. |
