Granted Patent B2

US 12,529,895 · App. 19/022,978 · Granted Jan 20, 2026

Inventors: Brian Bucknor (Miramar, FL); Christopher Lopez (Davie, FL); Michael Janusz Woods (Mountain View, CA); Aly H. M. Aly (Coral Springs, FL); James William Palmer (Miami, FL); Evan Francis Rynk (Boca Raton, FL)

Assignee: MAGIC LEAP, INC.

G02B27/017G01S1/68G01S1/70G01S1/7038G01S5/0247G01S5/0284G02B27/0093G06F1/163G06F3/012G06F3/014H01H9/0228H01H9/0235G02B2027/0138G02B2027/0178G02B27/0179G02B2027/0187G06F3/165

Abstract

Claims (49)

1 . A method of operating an electromagnetic (EM) tracking system for an augmented reality (AR) display system, the AR display system comprising a head-mounted AR display with a light field display, an EM emitter, and a portable user-input device that comprises an EM sensor, the method comprises:

emitting, by the EM emitter in the portable user-input device, a time-varying magnetic field;

detecting, by the EM sensor, the time-varying magnetic field;

determining, based at least in part on the detected time-varying magnetic field, a pose of the EM sensor;

determining, based at least in part on the determined pose, virtual content to display to a user of the AR display system; and

displaying, by the head-mounted AR display, the virtual content.

2 . The method of claim 1 , further comprising time-synchronizing the EM emitter and the EM sensor.

3 . The method of claim 1 , further comprising canceling magnetic interference from the detected time-varying magnetic field.

4 . The method of claim 1 , further comprising correlating real world coordinates associated with the pose of the EM sensor with virtual world coordinates associated with the virtual content.

5 . The method of claim 1 ,

wherein the EM emitter includes a first transmitter coil, a second transmitter coil, and a third transmitter coil, and wherein the method further comprises:

transmitting, with the first transmitter coil, a first magnetic field having a first frequency;

transmitting, with the second transmitter coil, a second magnetic field having a second frequency; and

transmitting, with the third transmitter coil, a third magnetic field having a third frequency.

6 . The method of claim 5 , wherein the EM emitter includes a time division multiplexed (TDM) circuit configured to multiplex the time-varying magnetic field, and wherein the method further comprises:

switching, with the TDM circuit, power among the first transmitter coil, the second transmitter coil, and the third transmitter coil.

7 . The method of claim 6 , wherein the first transmitter coil, the second transmitter coil, and the third transmitter coil are disposed along mutually orthogonal axes.

8 . The method of claim 6 , further comprising: dynamically turning, with the EM emitter, the first frequency, the second frequency, or the third frequency.

9 . The method of claim 6 , wherein the TDM circuit comprises an amplifier circuit that is TDM switched to each of the first, second, and third transmitter coils.

10 . The method of claim 6 , further comprising: synchronizing an on-board real-time clock (RTC) associated with the EM sensor with an RTC of the EM emitter.

11 . The method of claim 10 , wherein the synchronizing is performed by performed by one or more of: a wireless RF link established between a wireless interface of the EM sensor and a wireless interface of the EM emitter; or an electromagnetic pulse generated by the EM emitter to calculate a timing offset between the RTC of the EM sensor and the RTC of the EM emitter.

12 . The method of claim 10 , wherein the synchronizing is performed by Bluetooth Low Energy (BLE) protocol.

13 . The method of claim 6 , further comprising:

scanning, with the TDM circuit, for duplicated transmit frequencies by one or more of the first, second, or third transmitter coils, and

switching to an alternate transmit frequency if a duplicated transmit frequency is identified.

14 . The method of claim 6 , further comprising:

implementing, with the TDM circuit, a time sequence including:

transmitting, for a first time period, from the first transmitter coil while the second and third transmitter coils are substantially off;

transmitting, for a second time period, from the second transmitter coil while the first and third transmitter coils are substantially off; and

transmitting, for a third time period, from the third transmitter coil while the first and second transmitter coils are substantially off.

15 . The method of claim 1 , wherein the EM emitter includes an automatic gain control (AGC) circuit.

16 . A head-mounted display system, comprising:

a display positionable in front of eyes of a wearer;

an electromagnetic (EM) emitter, in a portable user-input device, configured to generate a time-varying magnetic field;

an EM sensor, in the portable user-input device, configured to sense the time-varying magnetic field; and

a processor programmed to:

determine, based at least in part on the sensed time-varying magnetic field, a pose of the EM sensor;

determine, based at least in part on the determined pose, virtual content to display to a user of the head-mounted display system; and

display, on the display, the virtual content.

17 . The head-mounted display system of claim 16 , wherein the processor is further programmed to time-synchronize the EM emitter and the EM sensor.

18 . The head-mounted display system of claim 16 , wherein the processor is further programmed to cancel magnetic interference from the sensed time-varying magnetic field.

19 . The head-mounted display system of claim 16 , wherein the processor is further programmed to correlate real world coordinates associated with the pose of the EM sensor with virtual world coordinates associated with the virtual content.

20 . An electromagnetic (EM) tracking system for an augmented reality (AR) display system,

an EM emitter, in a portable user-input device, configured to generate a time-varying magnetic field;

an EM sensor, in the portable user-input device, configured to detect the time-varying magnetic field;

a processor programmed to:

determine, based at least in part on the detected time-varying magnetic field,

a pose of the EM sensor; and

determine, based at least in part on the determined pose, virtual content to display to a user of the AR display system.

Assignments (2)

Continuity (8)

References Cited (251)