Stylus with Resonant Circuit

• US 20140104224A1
• Filed: 10/17/2012
• Published: 04/17/2014
• Est. Priority Date: 10/17/2012
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Ih, Ronald, Lyle, James D.
• Granted Patent: US 9,213,455 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H04B 5/0012 using capacitive coupling
• CPC Class Codes: H04B 5/0031 for data transfer
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

In one embodiment, at least one resonant circuit in a stylus receives a first signal from a touch sensor of a device. The first signal is received at the resonant circuit by capacitive coupling between the resonant circuit and a conductive element of the device'"'"'s touch sensor. A second signal based on the first signal and at least one of the at least one resonant circuit is then transmitted from the stylus to the device by capacitive coupling between the stylus and the touch sensor of the device.

Claims

1. A method comprising:

receiving, at least one resonant circuit in a stylus, by capacitive coupling between a conductive element of a touch sensor and the resonant circuit, a first signal from the touch sensor of a device; and

transmitting, by capacitive coupling between the stylus and the touch sensor of the device, a second signal from the stylus to the device, the second signal based on the first signal and at least one of the at least one resonant circuit.

2. The method of claim 1, wherein the stylus further comprises at least one interactive element operable to alter an electrical property of at least one of the at least one resonant circuit.

3. The method of claim 2, wherein altering the electrical property of at least one of the at least one resonant circuit comprises one or more of:

altering a capacitance of a capacitor in the at least one of the at least one resonant circuit;

altering an inductance of an inductor in the at least one of the at least one resonant circuit;

altering a resistance of a resistor in the at least one of the at least one resonant circuit;

selecting a crystal oscillator for inclusion in the at least one of the at least one resonant circuit; and

selecting a saw-tooth filter for inclusion in the at least one of the at least one resonant circuit.

4. The method of claim 1, wherein:

the at least one resonant circuit comprises a plurality of resonant circuits; and

the stylus further comprises at least one interactive element operable to select among the plurality of resonant circuits.

5. The method of claim 1, wherein transmitting, by capacitive coupling between the stylus and the touch sensor of the device, a second signal from the stylus to the device further comprises transmitting, by capacitive coupling between at least one of the at least one resonant circuit and the touch sensor of the device, the second signal from the at least one of the at least one resonant circuit to the touch sensor of the device.

6. The method of claim 1, wherein transmitting, by capacitive coupling between the stylus and the touch sensor of the device, a second signal from the stylus to the device further comprises transmitting, by capacitive coupling between at least one radio frequency identification element of the stylus and the touch sensor of the device, the second signal from the at least one radio frequency identification element to the touch sensor of the device.

7. The method of claim 1, wherein at least one of the at least one resonant circuit has a different Q factor than at least one other one of the at least one resonant circuit.

8. The method of claim 1, wherein the received first signal comprises a periodic signal with a frequency of at least 100 kilohertz.

9. A touch sensor comprising:

at least one first conductive element operable to transmit by capacitive coupling, between the at least one first conductive element and at least one resonant circuit in a stylus, a first signal to the at least one resonant circuit; and

at least one second conductive element operable to detect a second signal based on the first signal and at least one of the at least one resonant circuit; and

wherein the touch sensor is operable to process the received second signal.

10. The touch sensor of claim 9, wherein at least one of the at least one first conductive element is at least one of the at least one second conductive element.

11. The touch sensor of claim 9, wherein the at least one second conductive element operable to detect a second signal further comprises the at least one second conductive element further operable to receive, by capacitive coupling between the second conductive element and the stylus, the second signal based on the first signal and at least one of the at least one resonant circuit.

12. The touch sensor of claim 11, wherein the at least one second conductive element is further operable to receive, by capacitive coupling between the conductive element and at least one of the at least one resonant circuit, the second signal based on the first signal and at least one of the at least one resonant circuit.

13. The touch sensor of claim 11, wherein the at least one second conductive element is further operable to receive, by capacitive coupling between the conductive element and at least one radio frequency identification element of the stylus, the second signal based on the first signal and at least one of the at least one resonant circuit.

14. The touch sensor of claim 9, wherein the second signal comprises the first signal as modified by the capacitive coupling between the at least one first conductive element and the at least one resonant circuit in the stylus.

15. The touch sensor of claim 9, wherein the stylus further comprises at least one interactive element operable to alter an electrical property of at least one of the at least one resonant circuit.

16. The touch sensor of claim 15, wherein altering the electrical property of at least one of the at least one resonant circuit comprises one or more of:

altering a capacitance of a capacitor in the at least one of the at least one resonant circuit;

altering an inductance of an inductor in the at least one of the at least one resonant circuit;

altering a resistance of a resistor in the at least one of the at least one resonant circuit;

selecting a crystal oscillator for inclusion in the at least one of the at least one resonant circuit; and

selecting a saw-tooth filter for inclusion in the at least one of the at least one resonant circuit.

17. The touch sensor of claim 9, wherein:

the at least one resonant circuit comprises a plurality of the resonant circuits; and

the stylus further comprises at least one interactive element operable to select among the plurality of the resonant circuits.

18. The touch sensor of claim 9, wherein at least one of the at least one resonant circuit has a different Q factor than at least one other one of the at least one resonant circuit.

19. The touch sensor of claim 9, wherein the at least one first signal comprises a periodic signal with a frequency of at least 100 kilohertz.

20. A stylus comprising:

at least one resonant circuit operable to;

receive, by capacitive coupling between a conductive element of a touch sensor and the at least one resonant circuit, a first signal from the touch sensor of a device; and

transmit, by capacitive coupling between the stylus and the touch sensor of the device, a second signal from the stylus to the touch sensor of the device, the second signal based on the first signal and at least one of the at least one resonant circuit.