Voice coil array speaker
View Patent ↗Example embodiments provide a voice coil array speaker comprising a speaker assembly, a coil assembly, and a magnet assembly. The speaker assembly may comprise a speaker frame, a stationary base plate, a diaphragm configured to be capable of axial movement, a heat conducting front plate connected to the diaphragm, and thermal bridges configured to conduct heat from the heat conducting front plate to the speaker frame. The coil assembly may be connected to the heat conducting front plate, the coil assembly may comprise an array of coils wound around coil formers. The magnet assembly may be attached to the stationary base plate, the magnet assembly may comprise an array of laterally and vertically polarized magnets in contact with flux concentrators. The array of coils may be connected such that the direction of current flow alternates between clockwise and counterclockwise moving laterally across the array.
1 . A voice coil array speaker comprising:
a speaker assembly, the speaker assembly comprising,
a speaker frame,
a stationary base plate connected to the speaker frame,
a diaphragm connected to the speaker frame and configured to be capable of axial movement, and
a heat conducting front plate connected to the diaphragm, and
thermal bridges configured to conduct heat from the heat conducting front plate to the speaker frame;
a coil assembly connected to the heat conducting front plate, the coil assembly comprising an array of coils wound around coil formers; and
a magnet assembly attached to the stationary base plate, the magnet assembly comprising an array of laterally and vertically polarized magnets in contact with flux concentrators,
wherein the array of coils are connected such that the direction of current flow alternates between clockwise and counterclockwise moving laterally across the array.
2 . The voice coil array speaker of claim 1 , wherein
the flux concentrators correspond to and are aligned with coils of the arrays of coils, such that a concentrated uniform magnetic flux is directed laterally through the coils, and
a direction of magnetic flux between the flux concentrators and through the coils alternates from left to right moving laterally across the array.
3 . The voice coil array speaker of claim 2 , wherein the heat conducting front plate is supported by flexible mounts, such that the front plate and attached coil assembly is configured to move axially relative to the speaker frame and base plate.
4 . The voice coil array speaker of claim 3 , wherein
a force is produced by interaction of the array of coils with a magnetic field when subjected to electrical current flow, the force being the same direction in the array of coils;
the force causes axial movement of the diaphragm; and
the diaphragm causes alternating compression and rarefaction of the contacting air to produce the sound.
5 . The voice coil array speaker of claim 3 , wherein the array of laterally and vertically polarized magnets are arranged as a Halbach array, with alternating up and down polarization interspaced with alternating left and right polarization, the Halbach array directing the magnetic flux into the flux concentrators and through the coils in the array of coils.
6 . The voice coil array speaker of claim 3 , the magnet assembly further comprising:
shorting sleeves forming a complete conducting loop around the flux concentrators inside of the coils,
wherein current flowing through the array of coils induces current loops in the shorting sleeves, which cancel the magnetic flux from the coils and reduce flux linkage and inductance of the array of coils.
7 . The voice coil array speaker of claim 3 , wherein the coil formers are made of material with high thermal conductivity and conduct heat from the array of coils to the heat conducting front plate, where the heat is transferred through the thermal bridges to the speaker frame.
8 . The voice coil array speaker of claim 3 , wherein the coil formers include axial slits to prevent eddy currents from being induced in the coil former by a current through the voice coil or by relative motion of the coil former with a magnetic field.
9 . The voice coil array speaker of claim 3 , wherein the speaker frame includes fins to facilitate transfer of heat to surrounding air.
10 . The voice coil array speaker of claim 3 , wherein the array of coils are connected in series or in parallel.