Method and apparatus for modulating haptic feedback
The present invention concerns a method and apparatus for the modulation of an acoustic field for providing tactile sensations. A method of creating haptic feedback using ultrasound is provided. The method comprises the steps of generating a plurality of ultrasound waves with a common focal point using a phased array of ultrasound transducers, the common focal point being a haptic feedback point, and modulating the generation of the ultrasound waves using a waveform selected to produce little or no audible sound at the haptic feedback point.
1. A method of creating haptic feedback using ultrasound comprising the steps of:
using a plurality of ultrasonic transducers, generating a plurality of ultrasound waves, wherein at least two of the plurality of ultrasound waves form a focal point, wherein the focal point is a haptic feedback point that produces a tactile sensation;
first modulating the generating of the plurality of ultrasound waves using a waveform to produce a haptic sensation at the haptic feedback point by obtaining a modulation frequency that produces the haptic sensation, which produces less audible sound pressure level than would be produced at the haptic feedback point when second modulating the generating of the plurality of ultrasound waves using a square wave modulation pattern.
2. The method as in claim 1 , wherein the waveform is varied according to a linear interpolation.
3. The method as in claim 1 , wherein the waveform is varied according to a cosine interpolation.
4. The method as in claim 1 , wherein the waveform is varied according to a polynomial interpolation.
5. The method as in claim 1 , wherein the waveform is varied according to trigonometric interpolation.
6. The method as in claim 1 , wherein the waveform is varied according to a parametric speaker interpolation.
7. The method as in claim 1 , wherein the square wave modulation pattern matches the modulation frequency of the waveform.
8. The method as in claim 7 , wherein, at the focal point, a first peak amplitude of the first modulating is equal to a second peak amplitude of the second modulating.
9. The method as in claim 1 , wherein the waveform comprises an interpolation of phase of at least one of the plurality of the ultrasonic transducers.
10. The method as in claim 1 , wherein the waveform comprises an interpolation of amplitude of at least one of the plurality of the ultrasonic transducers.
11. The method of claim 1 , wherein the generating a plurality of ultrasound waves use ultrasound with a frequency at or above 40 kHz.
12. The method of claim 1 , wherein the first modulating the generating of the plurality of ultrasound waves uses a frequency from 1 Hz to 500 Hz.
13. The method of claim 1 , further comprising: varying a position of the focal point.
14. The method of claim 13 , wherein the position of the focal point is constantly varied.
15. The method of claim 13 , wherein the position of the focal point oscillates about a central point.
16. A system comprising:
a plurality of ultrasonic transducers for generation of a plurality of ultrasound waves, wherein at least two of the plurality of ultrasound waves form a focal point, wherein the focal point is a haptic feedback point that produces a tactile sensation;
a first modulation of the generation of the plurality of ultrasound waves using a waveform to produce a haptic sensation at the haptic feedback point by obtaining a modulation frequency that produces the haptic sensation, which produces less audible sound pressure level than would be produced at the haptic feedback point during a second modulation of the generation of the plurality of ultrasound waves using a square wave modulation pattern.
17. The system as in claim 16 , wherein the waveform is varied according to a linear interpolation.
18. The system as in claim 16 , wherein the waveform is varied according to a cosine interpolation.
19. The system as in claim 16 , wherein the waveform is varied according to a polynomial interpolation.
20. The system as in claim 16 , wherein the waveform is varied according to trigonometric interpolation.
21. The system as in claim 16 , wherein the waveform is varied according to a parametric speaker interpolation.
22. The system as in claim 16 , wherein the square wave modulation pattern matches the modulation frequency of the waveform.
23. The system as in claim 22 , wherein, at the focal point, a peak amplitude of the first modulation is equal to a peak amplitude of the second modulation.
24. The system as in claim 16 , wherein the waveform comprises an interpolation of phase of at least one of the plurality of the ultrasonic transducers.
25. The system as in claim 16 , wherein the waveform comprises an interpolation of amplitude of at least one of the plurality of the ultrasonic transducers.
26. The system of claim 16 , wherein the generation of the plurality of ultrasound waves use ultrasound with a frequency at or above 40 KHz.
27. The system of claim 16 , wherein the first modulation of the generation of the plurality of ultrasound waves uses a frequency from 1 Hz to 500 Hz.
28. The system of claim 16 , further comprising: variance of a position of the focal point.
29. The system of claim 16 , wherein the position of the focal point is constantly varied.
30. The system of claim 16 , wherein the position of the focal point oscillates about a central point.