| 摘要 |
PURPOSE:To obtain the stroboscopic reflecting umbrella which reflects a light beam to be diffused toward a Fresnel plate and is highly efficient and compact by providing an auxiliary reflecting plate which is increased in diameter in a taper shape to the front of an elliptically sectioned reflecting mirror. CONSTITUTION:This stroboscopic reflecting umbrella is equipped with the stroboscopic reflecting mirror 2 which is elliptically sectioned and has its reflecting surface extending almost to its front focus, a light emitting tube 1 which is provided nearby the rear focus of the reflecting mirror 2, the Fresnel plate 4 for light distribution control which is arranged in front of the reflecting mirror 2, and the auxiliary reflecting plate 3 which is provided at the opening part of the reflecting mirror 2 and increased in diameter in the taper shape. Then expressions I hold for the focal length of the reflecting mirror, the internal and external diameters of the light emitting tube, etc. Here, (a) and (b) are the lengths of the long and short sides of the reflecting mirrors, (f) the length from the center of the reflecting mirror to the focus, (d) the depth of the reflecting mirror RO and Ri the external and internal diameters of the light emitting tube, and Rc the length from the center of the reflecting mirror to the center of the light emitting tube. In such a case, light is prevented from being reflected inward by the reflecting plate to spread outward. Consequently, the stroboscopic reflecting mirror is compact and the utilization efficiency of luminous flux from the light emitting tube 1 is increased. |
