Multi-electrode active stylus tip

1. An active stylus configured to communicate with an external device, the active stylus comprising:

a controller; and

a pen tip including a plurality of electrodes,

wherein the plurality of electrodes are made of indium tin oxide (ITO), and

wherein each of the plurality of electrodes is configured as one of a drive electrode to transmit signals, a sense electrode to receive signals, a ground electrode, or a guard electrode, such that the plurality of electrodes include at least one drive electrode, at least one sense electrode, at least one ground electrode, and at least one guard electrode.

2. The active stylus of claim 1 , further comprising one or more mechanical switches operable to switch connectivity of one or more of the plurality of electrodes to the controller.

3. The active stylus of claim 1 , further comprising a multiplexer included in the pen tip.

4. The active stylus of claim 3 , wherein the multiplexer is configured to receive signals from the plurality of electrodes.

5. The active stylus of claim 1 , wherein the plurality of electrodes are formed of vertical segments that extend along a central vertical axis of the pen tip.

6. The active stylus of claim 1 , wherein the plurality of electrodes are formed of horizontal segments that extend not in parallel with a central vertical axis of the pen tip.

7. The active stylus of claim 1 , wherein the plurality of electrodes are disposed along a radial circumference of the pen tip as a ring surrounding a central vertical axis of the pen tip.

8. A system comprising:

a device; and

an active stylus configured to communicate with the device, the active stylus including:

a controller; and

a pen tip including a plurality of electrodes,

wherein the plurality of electrodes are made of indium tin oxide (ITO), and

wherein each of the plurality of electrodes is configured as one of a drive electrode to transmit signals, a sense electrode to receive signals, a ground electrode, or a guard electrode, such that the plurality of electrodes include at least one drive electrode, at least one sense electrode, at least one ground electrode, and at least one guard electrode.

9. The system of claim 8 , wherein the active stylus further includes one or more mechanical switches operable to switch connectivity of one or more of the plurality of electrodes to the controller.

10. The system of claim 8 , wherein the active stylus further includes a multiplexer.

11. The system of claim 10 , wherein the multiplexer is configured to receive signals from the plurality of electrodes.

12. The system of claim 8 , wherein the plurality of electrodes are disposed along a radial circumference of the pen tip as a ring surrounding a central vertical axis of the pen tip.

13. The system of claim 8 , wherein the active stylus is synchronized to the device based on signals transmitted from the device to the active stylus.

14. The system of claim 13 , wherein the stylus is synchronized to the device based on a bit sequence transmitted from the device to the active stylus.

15. A method executed between an active stylus and a device, wherein the active stylus includes a controller and a pen tip including a plurality of electrodes made of indium tin oxide (ITO), the method comprising:

configuring each of the plurality of electrodes as a drive electrode to transmit signals, a sense electrode to receive signals,

a ground electrode, or a guard electrode, such that the plurality of electrodes include at least one drive electrode, at least one sense electrode, at least one ground electrode, and at least one guard electrode; and

performing communication between the device and the active stylus using the configured plurality of electrodes of the active stylus.

16. The method of claim 15 , further comprising:

switching connectivity of one or more of the plurality of electrodes to the controller of the active stylus.