STYLUS DEVICE

• US 20140028634A1
• Filed: 07/27/2012
• Published: 01/30/2014
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Christoph Horst Krah, Martin Paul Grunthaner
• Inventors: KRAH, Christoph Horst, Yousefpor, Marduke, White, Kevin J., Grunthaner, Martin Paul
• Granted Patent: US 9,176,604 B2
• Time in Patent Office: Days
• US Class Current: 345/179
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

Styluses capable of generating stylus stimulation signals and touch sensitive devices capable of receiving stylus stimulation signals are disclosed. In one example, a stylus can receive a stimulation signal from a touch sensor of a touch sensitive device and generate a stylus stimulation signal by changing an amplitude or frequency of the received stimulation signal. The stylus can transmit the stylus stimulation signal back into the touch sensor of the touch sensitive device. The touch sensor can generate a touch signal based on the device'"'"'s own stimulation signals and the stylus stimulation signal. The touch sensitive device can process the touch signal to determine a location of the stylus on the touch sensor. The stylus can include a force sensor to detect an amount of force applied to a tip of the stylus. The stylus stimulation signal can be modulated based on the force detected by the force sensor.

Claims

1. A stylus comprising:

a stylus tip capable of receiving a stimulation signal from a touch sensitive device; and

an amplification circuit coupled to receive the stimulation signal from the stylus tip, wherein the amplification circuit is capable of modulating the received stimulation signal to generate a stylus stimulation signal, and wherein the stylus tip is further capable of transmitting the stylus stimulation signal to the touch-sensitive device.

2. The stylus of claim 1, further comprising a force sensor circuit capable of detecting a force applied to the stylus tip, wherein the amplification circuit is further capable of modulating the received stimulation signal by an amount corresponding to the force detected by the force sensor.

3. The stylus of claim 1, wherein a phase and a frequency of the stylus stimulation signal are at least substantially equal to a phase and a frequency of the stimulation signal from the touch sensitive device.

4. The stylus of claim 1, wherein the amplification circuit comprises a regenerative or super regenerative amplifier, and wherein a quench rate of the super regenerative amplifier is synchronous to at least a portion of the received stimulation signal and a gain of the super regenerative amplifier is based on the received stimulation signal.

5. The stylus of claim 1, wherein the amplification circuit comprises a processor capable of modulating a amplitude of the received stimulation signal.

6. A stylus comprising:

a stylus tip capable of receiving a stimulation signal from a touch sensitive device;

a frequency shifting circuit capable of changing a frequency of the received stimulation signal to generate a stylus stimulation signal; and

a stylus ring capable of transmitting the stylus stimulation signal to the touch-sensitive device.

7. The stylus of claim 6, wherein the frequency shifting circuit comprises:

an oscillator capable of generating an oscillating signal, the oscillating signal having a frequency that is different than a frequency of the stimulation signal from the touch sensitive device;

a modulation circuit capable of modulating an amplitude of the oscillating signal to generate a modulated oscillating signal;

a mixer coupled to receive the stimulation signal and the modulated oscillating signal, wherein the mixer is capable of generating the stylus stimulation signal by mixing the stimulation signal and the modulated oscillating signal.

8. The stylus of claim 7, wherein the frequency shifting circuit comprises a force sensor circuit capable of detecting a force applied to the stylus tip, wherein the modulation circuit is further capable of modulating the oscillating signal by an amount corresponding to the force detected by the force sensor.

9. The stylus of claim 8, wherein the oscillator is capable of turning on in response to the force detected by the force sensor being greater than a threshold amount.

10. The stylus of claim 6 further comprising a sense amplifier coupled to receive the stimulation signal from the touch sensitive device, the sense amplifier capable of amplifying the stimulation signal from the touch sensitive device to generate an amplified stimulation signal, wherein the frequency shifting circuit is coupled to receive the amplified stimulation signal, and wherein the frequency shifting circuit is capable of changing a frequency of the amplified stimulation signal.

11. A system comprising:

a capacitive touch sensor capable of generating one or more touch signals in response to one or more stimulations signals; and

a touch circuit capable of generating the one or more stimulation signals, wherein;

the touch circuit is coupled to transmit the one or more stimulation signals to the capacitive touch sensor and receive the one or more touch signals from the capacitive touch sensor;

the touch circuit is capable of determining a location of a stylus touch event detected by the capacitive touch sensor based at least in part on a touch signal of the one or more touch signals, the touch signal being generated in response to the one or more stimulation signals and a stylus stimulation signal generated by a stylus.

12. The system of claim 11, wherein the touch circuit comprises:

a first demodulation circuit capable of demodulating the touch signal of the one or more touch signals to generate a first demodulated touch signal; and

a first decoder circuit coupled to receive the first demodulated touch signal, wherein the first decoder circuit is capable of determining a location of a non-stylus touch event based at least in part on the first demodulated touch signal.

13. The system of claim 12 further comprising:

a second demodulation circuit capable of demodulating the touch signal of the one or more touch signals to generate a second demodulated touch signal; and

a second decoder circuit coupled to receive the second demodulated touch signal, wherein the second decoder circuit is capable of determining a location of a stylus touch event based at least in part on the second demodulated touch signal.

14. The system of claim 13, wherein the first demodulation circuit is capable of demodulating the touch signal of the one or more touch signals at a first frequency, and wherein the second demodulation circuit is capable of demodulating the touch signal of the one or more touch signals at a second frequency.

15. The system of claim 14, wherein the first frequency corresponds to a frequency of one or more stimulation signals, and wherein the second frequency corresponds to a frequency of the stylus stimulation signal.

16. A method comprising:

receiving a stimulation signal from a touch-sensitive device;

generating a stylus stimulation signal based on the received stimulation signal and a pressure detected by a pressure sensor; and

transmitting the generated stylus stimulation signal to the touch-sensitive device.

17. The method of claim 16, wherein generating the stylus stimulation signal comprising modulating an amplitude of the received stimulation signal based at least in part on the pressure detected by the pressure sensor and a gain vector.

18. The method of claim 16, wherein generating the stylus stimulation signal comprising changing a frequency of the received stimulation signal.

19. The method of claim 16, wherein generating the stylus stimulation signal comprising mixing an oscillating signal with the received stimulation signal, wherein a frequency of the oscillating signal is different than a frequency of the received stimulation signal.

20. The method of claim 19 further comprising modulating an amplitude of the oscillating signal before mixing the oscillating signal with the received stimulation signal, wherein the amplitude of the oscillating signal is modulated based at least in part on the pressure detected by the pressure sensor.

21. A method comprising:

receiving a stimulation signal from a touch sensitive device;

generating a stylus stimulation signal based on the received stimulation signal, wherein the stylus stimulation signal is generated by changing one of an amplitude or a frequency of the received stimulation signal; and

transmitting the generated stylus stimulation signal to the touch sensitive device.

22. The method of claim 21, wherein generating the stylus stimulation signal comprises modulating the amplitude of the received stimulation signal using a regenerative amplifier.

23. The method of claim 21, wherein generating the stylus stimulation signal comprises mixing an oscillating signal with the received stimulation signal, wherein a frequency of the oscillating signal is different than a frequency of the received stimulation signal.

24. The method of claim 21, wherein the stimulation signal from the touch sensitive device has a frequency between 100 KHz to 1 MHz, and wherein the stylus stimulation signal has a frequency within 50 KHz of the frequency of the touch sensitive device.

25. The method of claim 21, wherein the generated stylus stimulation signal is transmitted to the touch sensitive device through a ring of a stylus.