Optical sensor for sensing displacement speed or displacement of a moveable element in musical instrument

摘要

In an optical sensor for displacement speed/displacement of a movable element in a musical instrument, light emitted from a light- emitting element is guided to a sensor head through a transmission optical fiber and is further guided to a light-receiving element through a reception optical fiber. The sensor head is located at a position corresponding to a shutter movable in accordance with the movable element in the musical instrument. The shutter controls photocoupling and nonphotocoupling between the transmission and reception optical fibers. The sensor is of transmission or reflection type.