PURPOSE: To actuate with higher speed and to improve reliability and durability by driving magnetically a magnetic particle of a magnetic fluid enclosed in a mgnetic element.
CONSTITUTION: When the magnetic field by an electromagnet 6 has not been produced, magnetic particles in a magnetic fluid 5 of a magnetic element 3 have been diffused uniformly in a capsule having a transparent wall 4a and an optical reflection wall 4b, thus an incident light O is intercepted by the magnetic particles and any light is not fed to on optical exit path 2. On the other hand, when the electromagnet 6 is excited, magnetic particles are drawn, as shown by a code 5a, toward both magnetic poles N, S, the incident light O passes through a transparent wall 3a of the magnetic element 3 and a transparent liquid, and further is reflected at the optical reflective wall 3b and is fed as shown by a code O' to the optical exit path 2. Thus it is possible not only to switch an optical path but to adjust an amount of light by selecting properly viscosity of the magnetic fluid 6 of the magnetic element 3 and concentration of the magnetic particle, and by changing arbitrarily magnetic force by the electromagnet 6.
SUGIKI HIROYASU
KIMURA YUKINORI
