Surface and cordless transducer system

• US 8,022,937 B2
• Filed: 03/31/2008
• Issued: 09/20/2011
• Est. Priority Date: 04/01/2004
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Rodgers, James L., Palay, Steven M.
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): SPAR, ILANA L
• Application Number:
  US12/059,990
• Publication Number:
  US 20080181143A1
• Time in Patent Office: 1,268 Days
• Field of Search: 345173-179, 178 1801- 1811, 178 2001- 2004
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A smart surface is disclosed that can stand alone or be contained within a portable computer or other system, for powering and communicating with single or multiple cord-free transducers. Operating or charging power is transmitted by the surface using a carrier signal that is on/off keyed or amplitude modulated with synchronization, clock, enable, address, modes, commands and other pulse width, encoded or digital data. The signal is transmitted to single or multiple cordless smart transducers located on or above the surface, such as pens with multiple pressure sensing and switch capability, pointers, stylus, cursors, pucks, mouse, pawns, implements and similar items. Overlapping resonant inductive circuits are used in the surface to transmit operating power and communicate data to the transducer(s).

Claims

1. A surface and cordless transducer system, the system comprising:

a surface including a position resolving grid, and

a transducer including a power receiving circuit, wherein the power receiving circuit responds to an electromagnetic field radiating from the surface and sends a transmit signal, which is received by the position resolving grid and used to determine a position of the transducer relative to the surface,

wherein the surface further includes a plurality of power transmission coils, which are distinct from the position resolving grid, for radiating the electromagnetic field, the plurality of power transmission coils being overlapping resonant power transmission coils that are configured to generate current multiplication associated with resonance therein, and are further configured to supply power and data to the transducer.

2. The surface and cordless transducer system of claim 1, wherein the data that is supplied with the power to the transducer in the electromagnetic field radiating from the resonant power transmission coils is encoded.

3. The surface and cordless transducer system of claim 1, wherein the power and the data supplied to the transducer in the electromagnetic field radiating from the resonant power transmission coils are modulated.

4. The surface and cordless transducer system of claim 1, wherein the data that is supplied with the power to the transducer in the electromagnetic field radiating from the resonant power transmission coils comprises an address command to individually turn on the transducer.

5. The surface and cordless transducer system of claim 1, further comprising memory that is configured to store the data that is supplied with the power to the transducer in the electromagnetic field radiating from the resonant power transmission coils.

6. The surface and cordless transducer system of claim 1, wherein the position resolving grid and the resonant power transmission coils are arranged on top of one another to form the surface.

7. The surface and cordless transducer system of claim 1, wherein the transducer includes an energy storage portion that is configured to store power for operating the transducer based on a signal from the power receiving circuit in response to the electromagnetic field radiating from the resonant power transmission coils arranged on the surface.

8. The surface and cordless transducer system of claim 1, wherein each of the resonant power transmission coils, when inactive, is configured to be tuned to a frequency that is different from its operating frequency so as to minimize an electromagnetic interference with the position resolving grid.

9. The surface and cordless transducer system of claim 1, wherein a continuous transmission of a signal from the resonant power transmission coils is stopped when the surface is receiving a transmit signal from the transducer.

10. The surface and cordless transducer system of claim 1, wherein the transducer is configured to perform a predefined modulation on a transmit signal to be sent to the position resolving grid.

11. The surface and cordless transducer system of claim 10, wherein the predefined modulation comprises a time keying modulation or an on/off modulation.

12. A method for determining a position of a transducer relative to a surface, wherein the surface includes a position resolving grid and the transducer includes a power receiving circuit, the method comprising:

causing the power receiving circuit to respond to an electromagnetic field radiating from the surface and to send a transmit signal, and

causing the position resolving grid to receive the transmit signal from the transducer to thereby determine a position of the transducer relative to the surface,

wherein the surface further includes a plurality of power transmission coils, which are distinct from the position resolving grid and which are overlapping resonant power transmission coils that are configured to generate current multiplication associated with resonance therein, and the method further comprises;

causing the plurality of overlapping resonant power transmission coils to radiate the electromagnetic field to thereby supply power and data to the transducer.

13. The method of claim 12, further comprising encoding the data that is supplied with the power to the transducer in the electromagnetic field radiating from the resonant power transmission coils.

14. The method of claim 12, further comprising modulating the power and the data supplied to the transducer in the electromagnetic field radiating from the resonant power transmission coils.

15. The method of claim 12, wherein the data that is supplied with the power to the transducer in the electromagnetic field radiating from the resonant power transmission coils comprises an address command to individually turn on the transducer.

16. The method of claim 12, wherein the data that is supplied with the power to the transducer is stored in memory.

17. The method of claim 12, further comprising tuning each of the resonant power transmission coils, when inactive, to a frequency that is different from its operating frequency so as to minimize an electromagnetic interference between the power transmission coil and the position resolving grid.

18. The method of claim 12, further comprising stopping a continuous transmission of a signal from the resonant power transmission coils when the surface is receiving a transmit signal from the transducer.

19. The method of claim 12, further comprising causing the transducer to perform a predefined modulation on a transmit signal to be sent to the position resolving grid.

20. The method of claim 19, wherein the predefined modulation comprises a time keying modulation or an on/off modulation.