Variable light attenuator

Abstract

Abstract PURPOSE:To readily voluminously produce the small-size and high-accuracy variable light attenulator by forming a light absorbing body evenly dispersed with black material in transparent plastics and changing the thickness continuously or stepwise in the circumferential direction aboue the rotating axis. CONSTITUTION:A light absorbing body 1 assumes the cylindrical shape centering about a revolving shaft 2 integrally with a transparent body 3. Light 7 from an optical fiber 6 is converted to parallel rays by a rod lens 8 and the parallel rays transmit in the order of an antireflecting film 4, transparent body 3, light absorbing body 1 and antireflecting film 5 and are condensed to an optical fiber 10 by a rod lens 9. The light 7 attenuates at the exponential function of the thickness of the light absorbing body 1 and the thickness changes at a fixed ratio in the circumferential direction and therefore the rotating angle may be graduated at an equal spacing in dB unit and these are manufactured simply by changing the ratios of black material by the use of the same die. Thereby, the small-size and high-accuracy variable light attenuator may be readily volume-produced.

Inventors

• 👤 Ritsuo Hasumi

Bibliographic Details