Method and apparatus for modulating haptic feedback
View Patent ↗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:
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 audible sound at the haptic feedback point.
2. The method as in claim 1 further comprising the step of avoiding sharp pressure changes at the focal point.
3. The method as claim 2 further comprising the step of modulating the generation of the ultrasound waves with a waveform comprising an interpolation of the transducer phases and amplitudes.
4. The method as claim 3 , wherein the interpolation is a linear interpolation.
5. The method as in claim 3 , wherein the interpolation is selected from the group consisting of a polynomial interpolation and a trigonometric interpolation.
6. The method as in claim 3 , wherein the interpolation is a cosine interpolation.
7. The method as in claim 3 , wherein the interpolation is a parametric speaker interpolation.
8. The method as in claim 1 further comprising the step of varying the position of the common focal point.
9. The method as in claim 8 , wherein the position of the common focal point is constantly varied.
10. The method as in claim 8 , wherein the position of the common focal point oscillates about a central focal point.
11. A haptic feedback system comprising:
a phased array comprising a plurality of transducers arranged to emit ultrasound to create a haptic feedback point, the phased array arranged to emit ultrasound according to a modulation waveform having a shape that produces little or no sound when the ultrasound converges at the haptic feedback point.
12. The haptic feedback system as in claim 11 further comprising a control unit.
13. The haptic feedback system as in claim 11 further comprising a driving unit.
14. The haptic feedback system as in claim 13 , wherein the driving unit is arranged to drive the transducer to produce ultrasound.
15. The haptic feedback system as in claim 14 further comprising a control unit arranged to send control signals to the driving unit.
16. The haptic feedback system as in claim 12 , wherein the control unit includes a memory.
17. The haptic feedback system as in claim 12 , wherein the control unit is arranged to modulate the output of the transducer according to a particular modulation waveform.
18. The haptic feedback system as in claim 17 , wherein the modulation waveform is a linear interpolation.
19. The haptic feedback system as in claim 17 , wherein the modulation waveform is an interpolation selected from the group consisting of a polynomial interpolation and a trigonometric interpolation.
20. The haptic feedback system as in claim 17 , wherein the modulation waveform is a cosine interpolation.
21. The haptic feedback system as in claim 17 , wherein the modulation waveform corresponds to a parabolic speaker interpolation.