US 11,877,126 B2
Inductive excursion sensing for audio transducers
Michael Asfaw, Santa Monica, CA (US); Chad Georges Seguin, Campbell, CA (US); David C. Breece, III, Palo Alto, CA (US); and Leonardo Kusumo, San Jose, CA (US)
Assigned to Google LLC, Mountain View, CA (US)
Filed by Google LLC, Mountain View, CA (US)
Filed on Sep. 13, 2021, as Appl. No. 17/473,266.
Application 17/473,266 is a continuation of application No. 16/753,609, granted, now 11,146,900, previously published as PCT/US2018/065778, filed on Dec. 14, 2018.
Claims priority of provisional application 62/599,570, filed on Dec. 15, 2017.
Prior Publication US 2021/0409884 A1, Dec. 30, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H04R 29/00 (2006.01); G01D 5/20 (2006.01)
CPC H04R 29/001 (2013.01) [G01D 5/2066 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An audio speaker system comprising:
a frame having a surface extending in a plane;
a flexible printed circuit (FPC) coupled to the surface of the frame, wherein the FPC includes a sense coil;
a magnet;
a voice coil defining an axis extending in a first direction non-parallel to the plane and positioned in a magnetic field of the magnet, the voice coil being configured to oscillate along the first direction when the voice coil is energized; and
an excursion measuring system configured to perform operations comprising:
determining an electrical parameter of current flow in the sense coil; and
based on the electrical parameter, determining a distance between the voice coil and the sense coil in the first direction.