ELECTROMAGNETIC 3D STYLUS

• US 20130002614A1
• Filed: 06/28/2011
• Published: 01/03/2013
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Nowatzyk, Andreas, Thacker, Charles P.
• Granted Patent: US 8,933,913 B2
• Time in Patent Office: Days
• US Class Current: 345/179
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/046 by electromagnetic means
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A stylus system and method for determining the three-dimensional position and orientation of a stylus operating within a volume located above a surface of a display device is described. In some embodiments, the stylus system includes a stylus and a display device. The stylus senses one or more magnetic fields generated from a set of transmitting coils associated with the display device and transmits sensing information over an RF channel to a receiver in the display device. The display device determines the three-dimensional position of the stylus by applying a cell-based position reconstruction technique that compares the received sensing information with predetermined magnetic field values associated with one or more predetermined regions located above the surface of the display device. The cell-based position reconstruction technique accommodates magnetic field distortions due to the presence of conductive elements within or near the display device.

Claims

1. A method for determining a position of a stylus, comprising:

generating one or more drive signals, each of the one or more drive signals is associated with a particular transmission coil of one or more transmission coils, the one or more transmission coils are associated with a display device;

generating one or more magnetic fields, each of the one or more magnetic fields is associated with a particular drive signal of the one or more drive signals;

sensing one or more voltages, each of the one or more voltages is associated with a particular receiving coil of one or more receiving coils, the one or more voltages are generated by the one or more magnetic fields, the one or more receiving coils are associated with the stylus;

transmitting sensing information based on the one or more voltages from the stylus to the display device; and

determining the position of the stylus within one or more predetermined regions located above a surface of the display device, the determining the position of the stylus includes determining a first region of the one or more predetermined regions based on the received sensing information.

2. The method of claim 1, wherein:

the first region is associated with one or more polynomials describing magnetic fields associated with each of the one or more transmission coils.

3. The method of claim 1, wherein:

the sensing information includes a set of field numbers that represent the sensed magnetic field strength from each of the one or more transmission coils to each of the one or more receiving coils.

4. The method of claim 3, wherein:

the determining the first region includes comparing a predetermined field magnitude associated with the first region with a particular number of the set of field numbers; and

the first region comprises a cubic region.

5. The method of claim 4, wherein:

each of the one or more drive signals includes an FM chirp signal.

6. The method of claim 5, wherein:

the transmitting sensing information transmits the sensing information over a single RF channel.

7. The method of claim 1, wherein:

the one or more drive signals are time multiplexed such that only one of the one or more transmission coils generates a magnetic field at a particular point in time.

8. The method of claim 1, wherein:

the one or more transmission coils include at least two coils arranged in a first direction and at least two other coils arranged in a second direction orthogonal to the first direction.

9. A stylus system, comprising:

a stylus, the stylus includes one or more receiving coils, the one or more receiving coils include a first coil arranged in a first direction and a second coil arranged in a second direction, the one or more receiving coils include a third coil arranged in a third direction, the first direction is orthogonal to the second direction and the third direction, the second direction is orthogonal to the first direction and the third direction; and

a display device, the display device includes a stylus controller and one or more transmission coils, the stylus controller generates one or more drive signals, each of the one or more drive signals is associated with a particular transmission coil of the one or more transmission coils, the stylus controller drives each of the one or more transmission coils with a particular drive signal of the one or more drive signals, the stylus controller receives sensing information from the stylus based on one or more magnetic fields associated with the one or more transmission coils, the stylus controller determines a position of the stylus within a volume located above a surface of the display device, the volume is associated with one or more predetermined regions, the one or more predetermined regions are located relative to the surface of the display device, the determination of the position of the stylus includes determining a first region of the one or more predetermined regions based on the received sensing information.

10. The stylus system of claim 9, wherein:

the first region is associated with one or more polynomials describing magnetic fields associated with each of the one or more transmission coils.

11. The stylus system of claim 9, wherein:

the sensing information includes a set of field numbers that represent the sensed magnetic field strength from each of the one or more transmission coils to each of the one or more receiving coils.

12. The stylus system of claim 11, wherein:

the determining the first region includes comparing a predetermined field magnitude associated with the first region with a particular number of the set of field numbers; and

the first region comprises a cubic region.

13. The stylus system of claim 12, wherein:

each of the one or more drive signals includes an FM chirp signal.

14. The stylus system of claim 13, wherein:

the stylus controller receives sensing information over a single RF channel.

15. The stylus system of claim 9, wherein:

the one or more drive signals are time multiplexed such that only one of the one or more transmission coils generates a magnetic field at a particular point in time.

16. The stylus system of claim 9, wherein:

the one or more transmission coils include at least two coils arranged in a first direction and at least two other coils arranged in a second direction orthogonal to the first direction.

17. One or more storage devices containing processor readable code for programming one or more processors to perform a method for determining a position of a stylus comprising the steps of:

calibrating one or more predetermined regions associated with a display device, the one or more predetermined regions are located relative to a surface of the display device;

generating one or more drive signals, each of the one or more drive signals is associated with a particular transmission coil of one or more transmission coils, the one or more transmission coils are associated with the display device, the one or more transmission coils include at least two coils arranged in a first direction and at least two other coils arranged in a second direction orthogonal to the first direction;

generating one or more magnetic fields, each of the one or more magnetic fields is associated with a particular drive signal of the one or more drive signals;

sensing one or more voltages, each of the one or more voltages is associated with a particular receiving coil of one or more receiving coils, the one or more voltages are generated by the one or more magnetic fields, the one or more receiving coils are associated with the stylus;

transmitting sensing information based on the one or more voltages from the stylus to the display device, the sensing information includes voltage information associated with the sensed magnetic field strength from each of the one or more receiving coils; and

determining the position of the stylus within a volume located above the surface of the display device using a cell-based position reconstruction technique, the volume is associated with the one or more predetermined regions, the cell-based position reconstruction technique includes determining a first region of the one or more predetermined regions based on the received sensing information.

18. The one or more storage devices of claim 17, wherein:

the first region is associated with one or more polynomials describing magnetic fields associated with each of the one or more transmission coils; and

the first region comprises a cubic region of space.

19. The one or more storage devices of claim 18, wherein:

the determining the first region includes comparing a predetermined field magnitude associated with the first region with the voltage information.

20. The one or more storage devices of claim 19, wherein:

the sensing information is transmitted over a single RF channel; and

each of the one or more drive signals includes an FM chirp signal.