US 12,089,025 B2
Speaker
Hiroki Toita, Fukushima (JP)
Assigned to ALPS ALPINE CO., LTD., Tokyo (JP)
Filed by Alps Alpine Co., LTD, Tokyo (JP)
Filed on Aug. 12, 2022, as Appl. No. 17/886,827.
Claims priority of application No. 2021-135710 (JP), filed on Aug. 23, 2021.
Prior Publication US 2023/0057212 A1, Feb. 23, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04R 9/06 (2006.01); H04R 9/02 (2006.01)
CPC H04R 9/06 (2013.01) [H04R 9/025 (2013.01); H04R 2400/11 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A speaker having a vibration unit that has a diaphragm, a bobbin fixed to the diaphragm, and a voice coil disposed on the bobbin, a support unit that supports the vibration unit so that the vibration unit vibrates, and a magnetic circuit unit included in the support unit, wherein:
the magnetic circuit unit has a magnetic gap in which the voice coil is positioned, an inner yoke positioned more inside than is the magnetic gap, and a fixed magnet that forms a driving magnetic flux that traverses the magnetic gap and flows in the inner yoke in a vibration direction in which the vibration unit vibrates;
a movable magnet is fixed to the vibration unit, the movable magnet forming a movable magnetic flux oriented so as to cross the vibration direction;
a magnetic sensor is fixed to the support unit, the magnetic sensor being positioned more inside than is the magnetic gap when viewed in a plane perpendicular to the vibration direction; and
a fixed magnetic field component and a movable magnetic field component are detected by the magnetic sensor, the fixed magnetic field component acting in the vibration direction according to a leakage flux from the magnetic circuit unit, the movable magnetic field component acting in a direction crossing the fixed magnetic field component, according to the movable magnetic flux, and operation of the vibration unit is measured according to a change in strength of the movable magnetic field component.