STYLUS LOCATION UTILIZING MULTIPLE MAGNETOMETERS

• US 20140168174A1
• Filed: 12/13/2012
• Published: 06/19/2014
• Est. Priority Date: 12/13/2012
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: IDZIK, Jacek S., MERCEA, Cornel
• Granted Patent: US 9,262,033 B2
• Time in Patent Office: Days
• US Class Current: 345/179
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

The present disclosure provides a host electronic device, a stylus and a method for determining the location of a stylus with respect to a host electronic device. A magnetic field generator of the stylus is energized and a first magnetic field is sensed at two or more magnetometers of the host electronic device. The location of the stylus with respect to the host electronic device is determined dependent upon the first magnetic field. A second magnetic field may be sensed, while the magnetic field generator is either deactivated or energized with an opposite polarity, to correct for the presence of a background magnetic field. The magnetometers may be directional magnetometers and may be arranged in an array.

Claims

1. An electronic device comprising:

a first directional magnetometer, operable to sense a first magnetic field vector comprising two or more first components of a magnetic field produced by a magnetic field generator in proximity to the electronic device;

at least one second directional magnetometer, operable to sense at least one second magnetic field vector comprising two or more components of the magnetic field produced by the magnetic field generator; and

a processor coupled to the first and second directional magnetometers and responsive to the first magnetic field vector and the at least one second magnetic field vector, the processor operable to determine a location of the magnetic field generator with respect to the electronic device.

2. The electronic device of claim 1, where the electromagnetic field generator is located in a stylus and where the electronic device further comprises:

a communication circuit operable to communicate with a control circuit of the stylus that controls an electric current supplied to the electromagnetic field generator of the stylus.

3. The electronic device of claim 1, where the processor is further operable to:

determine a first magnetic field comprising the first magnetic field vector and the at least one second magnetic field vector sensed when the magnetic field generator is inactive; and

determine a second magnetic field comprising the first magnetic field vector and the at least one second magnetic field vector sensed when the magnetic field generator is active,

and where the processor is responsive to a difference between the second magnetic field and the first magnetic field to determine the location of the magnetic field generator with respect to the electronic device.

4. The electronic device of claim 1, where the first directional magnetometer and the at least one second directional magnetometer comprise an array of magnetometers.

5. The electronic device of claim 4, further comprising a screen, where the array of magnetometers comprises a planar array aligned with and in close proximity to the screen.

6. The electronic device of claim 1, where the first directional magnetometer comprises a two-axis magnetometer.

7. The electronic device of claim 1, where the first directional magnetometer comprises a three-axis magnetometer.

8. A stylus operable to provide input to a host electronic device, the stylus comprising:

an electromagnetic field generator;

a control circuit operable to provide an electric current to the electromagnetic field generator; and

a communication module operatively coupled to the control circuit and operable to communicate with the host electronic device.

9. The stylus of claim 8, where the electromagnetic field generator comprises a coil located in close proximity to a ferrous body.

10. The stylus of claim 8, where the control circuit is responsive to a communication signal received from the communication module.

11. The stylus of claim 8, where the communication module is operable to communicate a state of the control circuit to the host electronic device.

12. The stylus of claim 8, further comprising:

a contact sensor operable to sense when a tip of the stylus is in contact with a screen of the host electronic device,

where the communication module is operable to communicate to the host electronic device when the tip of the stylus is in contact with the screen of the host electronic device.

13. A method for determining a location of a stylus relative to a host electronic device, comprising:

activating an electromagnet of the stylus;

sensing a first magnetic field at two or more magnetometers of the host electronic device; and

determining the location of the stylus with respect to the host electronic device dependent upon the first magnetic field.

14. The method of claim 13, further comprising:

sensing a second magnetic field at two or more magnetometers of the host electronic device;

where determining the location of the stylus with respect to the host electronic device is dependent upon the first and second magnetic fields.

15. The method of claim 14, further comprising:

deactivating the electromagnet of the stylus when the second magnetic field is sensed; and

determining the location of the stylus with respect to the host electronic device dependent upon a difference between the first and second magnetic fields.

16. The method of claim 14, further comprising:

energizing the electromagnet of the stylus in a first polarity when the first magnetic field is sensed;

energizing the electromagnet of the stylus in a second polarity, opposite to the first polarity, when the first magnetic field is sensed; and

determining the location of the stylus with respect to the host electronic device dependent upon a difference between the first and second magnetic fields.

17. The method of claim 13, where determining the location of the stylus with respect to the host electronic device comprises:

determining directions of the first magnetic field at the two or more magnetometers.

18. A non-transitory computer-readable medium having computer-executable instructions that, when executed by a processor of a host electronic device, cause the host electronic device to determine a location of a stylus relative to the host electronic device, by:

sensing first magnetic vectors at two or more magnetometers of the host electronic device, the first magnetic field vectors dependent in part upon a first magnetic field of the stylus;

sensing second magnetic vectors at the two or more magnetometers of the host electronic device, the second magnetic field vectors dependent in part upon a second magnetic field of the stylus; and

determining the location of the stylus with respect to the host electronic device dependent upon the first and second magnetic field vectors.

19. The non-transitory computer-readable medium of claim 18 having further computer-executable instructions that, when executed by the processor of the host electronic device, cause the host electronic device to determine a location of a stylus relative to the host electronic device, by:

cooperating with the stylus such that the first magnetic field of the stylus is a zero magnetic field and the second magnetic field of the stylus is a non-zero magnetic field; and

determining the location of the stylus with respect to the host electronic device dependent upon a difference between the first and second magnetic field vectors.

20. The non-transitory computer-readable medium of claim 18 having further computer-executable instructions that, when executed by the processor of the host electronic device, cause the host electronic device to determine a location of a stylus relative to the host electronic device, by:

cooperating with the stylus such that the first magnetic field of the stylus is opposite in polarity to the second magnetic field of the stylus; and

determining the location of the stylus with respect to the host electronic device dependent upon a difference between the first and second magnetic field vectors.

21. A system comprising:

a stylus comprising;

an electromagnetic field generator;

a control circuit operable to provide an electric current to the electromagnetic field generator; and

a communication module operatively coupled to the control circuit; and

a host electronic device comprising;

a first directional magnetometer, operable to sense a first magnetic field vector comprising two or more first components of a magnetic field produced by the electromagnetic field generator of the stylus;

at least one second directional magnetometer, operable to sense at least one second magnetic field vector comprising two or more components of the magnetic field produced by the electromagnetic field generator of the stylus;

a processor coupled to the first and second directional magnetometers and responsive to the first magnetic field vector and the at least one second magnetic field vector, the processor operable to determine a location of the electromagnetic field generator of the stylus with respect to the electronic device; and

a communication circuit operable to communicate with the communication module of the stylus.