Multi-layer board actuator having a planar magnet and voice coil

Inventors: Stuart M. Nevill (Los Gatos, CA); Minghe Liu (San Jose, CA); Justin D. Crosby (Cupertino, CA); David S. Wilkes, Jr. (San Jose, CA)

Assignee: Apple Inc.

H04R9/047 H04R7/04 H04R7/06 H04R7/10 H04R7/22 H04R9/046 H04R9/06 H04R2209/041

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Quick Facts

Patent No.: US 12701364
App. No.: 18/365,108
Granted: Aug 4, 2026
Kind: B2

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Abstract

An actuator assembly comprising: a multi-layer board comprising a first side and a second side defining an actuation region having a thickness that is reduced relative to a remainder of the multi-layer board; a planar voice coil formed by a trace on at least one of the first side or the second side defining the actuation region; and a polarized magnet array having a magnetic field aligned to the planar voice coil to actuate the actuation region upon application of a voltage to the planar voice coil.

Claims (28)

1 . An actuator assembly comprising:

a multi-layer printed circuit board comprising a first side and a second side defining an actuation region having a first thickness that is reduced relative to a second thickness of the multi-layer printed circuit board;

a planar voice coil formed by a trace on at least one of the first side or the second side of the multi-layer printed circuit board defining the actuation region; and

a polarized magnet array having a magnetic field aligned to the planar voice coil to actuate the actuation region upon application of a voltage to the planar voice coil.

2 . The actuator assembly of claim 1 wherein the actuation region comprises a local bending mode that has a different bending mode than a portion of the multi-layer printed circuit board having the second thickness.

3 . The actuator assembly of claim 1 wherein the reduced thickness at the actuation region is between one-half to one-third of the second thickness of the multi-layer printed circuit board.

4 . The actuator assembly of claim 1 wherein the planar voice coil comprises a first planar voice coil formed by a trace on the first side and a second planar voice coil formed by a trace on the second side.

5 . The actuator assembly of claim 4 wherein a third planar voice coil is formed by a trace on a layer of the multi-layer printed circuit board between the first side and the second side.

6 . The actuator assembly of claim 1 wherein the planar voice coil comprises a spiral voice coil confined to the actuation region.

7 . The actuator assembly of claim 1 wherein the polarized magnet array is axially polarized and comprises a central magnet surrounded by a number of side magnets.

8 . The actuator assembly of claim 1 wherein the polarized magnet array comprises an arrangement of permanent magnets having a spatially rotating pattern of magnetization.

9 . The actuator assembly of claim 1 wherein the polarized magnet array is coupled to the first side or the second side of the multi-layer printed circuit board.

10 . The actuator assembly of claim 1 wherein the polarized magnet array is coupled to a fixed structure arranged along the first side of the multi-layer printed circuit board and the second side faces a recessed region formed in the multi-layer printed circuit board.

11 . The actuator assembly of claim 1 wherein the multi-layer printed circuit board comprises a flexible multi-layer printed circuit board.

12 . An electronic device comprising:

a device housing;

a multi-layer printed circuit board coupled to the device housing, the multi-layer printed circuit board comprising a number of material layers and an actuation region formed by less than all of the number of material layers;

a planar voice coil formed in the actuation region by a conductive trace of at least one of the number of material layers of the multi-layer printed circuit board;

a magnet array having a magnetic field aligned to the planar voice coil to actuate the actuation region upon application of a voltage to the planar voice coil; and

a circuit coupled to the planar voice coil to apply the voltage to the planar voice coil.

13 . The electronic device of claim 12 wherein the actuation region comprises a local bending mode of from about 1.5 kHz to about 2.5 kHz and that is different than a bending mode of another region of the multi-layer printed circuit board.

14 . The electronic device of claim 12 wherein the multi-layer printed circuit board comprises alternating conductive layers and non-conductive layers and the actuation region is formed by less than all of the non-conductive layers.

15 . The electronic device of claim 12 wherein the planar voice coil comprises a first planar voice coil formed by a first conductive trace on a first side of the at least one material layer and a second planar voice coil formed by a second conductive trace on a second side of the at least one material layer.

16 . The electronic device of claim 15 wherein a third planar voice coil is formed by a third conductive trace on another material layer coupled to the at least one material layer.

17 . The electronic device of claim 12 wherein the planar voice coil comprises a spiral voice coil confined to the actuation region.

18 . The electronic device of claim 12 wherein the magnet array is axially polarized and comprises a central magnet surrounded by a number of side magnets.

19 . The electronic device of claim 12 wherein the magnet array comprises an arrangement of permanent magnets having a spatially rotating pattern of magnetization.

20 . The electronic device of claim 12 wherein the magnet array comprises a first magnet coupled to a first side of the at least one material layer and a second magnet coupled to a second side of the at least one material layer.