Optical sensor for detecting loudspeaker membrane deflections e.g. for controlled -operation loudspeakers, has optical sensor and opposite-facing light source mounted with oscillation coil between them for partial covering of optical sensor

摘要

An optical sensor e.g. a photo-transistor or photo-transistor array is arranged in the pole core (or interior space of the ring-magnet) of a loudspeaker and a light-source e.g. LED or LED array is mounted in the interior of the ring-magnet (or in the pole core). The optical sensor and opposite-facing light source are mounted so that the back end of the oscillation coil is between them and thus the optical sensor is partly covered, the covering of the optical sensor being an analog of the deflection of the oscillation coil.