Touch sensitive device
A touch sensitive device comprising a touch surface, a force exciter coupled to the touch surface to excite vibration in the surface in response to a signal sent to the exciter, with the touch surface and exciter together forming a coupled system and a signal generator to generate the signal, with the signal generator generating a carrier wave signal at frequencies within the frequency bandwidth of the coupled system and modulating the carrier wave signal with a complex modulation where the modulated carrier wave signal has a time response comparable to that of a low frequency signal which produces a desired haptic sensation whereby a user touching the touch surface excited by the exciter in response to the modulated carrier wave signal experiences the desired haptic sensation which is perceived at a frequency below the frequency bandwidth of the coupled system.
1. A method comprising:
detecting a user's touch of a touch surface of a display panel, the display panel coupled to an actuator, wherein the actuator and display panel define a coupled system; and
in response to the detecting, driving the actuator to provide an excitation of the coupled system with a carrier wave signal at a frequency in a range from 100 Hz to 400 Hz, wherein driving the actuator comprises modulating an amplitude and/or the frequency of the carrier wave signal to provide a modulated signal, the modulated signal having a modulation envelope that has a modulation frequency between 10 Hz and 40 Hz,
wherein the actuator is driven while the user touches the display panel to provide a haptic sensation to the user comprising a vibration at the modulation frequency.
2. The method of claim 1 , wherein the actuator comprises a distributed mode actuator and the frequency range of the coupled system is between 150 Hz to 350 Hz.
3. The method of claim 1 , wherein the actuator comprises a piezoelectric actuator and the frequency range of the coupled system is between 100 Hz to 300 Hz.
4. The method of claim 1 , wherein the actuator comprises an electromagnetic actuator and the frequency range of the coupled system is between 150 Hz to 300 Hz.
5. The method of claim 1 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises phase modulation.
6. The method of claim 1 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises pulse width modulation.
7. The method of claim 1 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises pulse rate modulation.
8. The method of claim 1 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises superimposing a plurality of carrier wave signal pulse trains of different amplitudes, phases and/or frequencies.
9. A device, comprising:
a coupled system comprising:
a display panel comprising a touch surface; and
an actuator coupled to the display panel; and
a sensor configured to detect a user's touch of the touch surface of the display panel; and
an impulse generator,
wherein, in response to detecting the user's touch, the impulse generator is configured to drive the actuator with a carrier wave signal at a frequency in a range from 100 Hz to 400 Hz, wherein the driving comprises modulating an amplitude and/or the frequency of the carrier wave signal to provide a modulated signal, the modulated signal having a modulation envelope that has a modulation frequency between 10 Hz and 40 Hz, the modulation envelope comprising a pulse that includes a pair of extrema separated by a time interval corresponding to cycle of the modulation frequency,
wherein the actuator is driven while the user touches the display panel to provide a haptic sensation to the user comprising a vibration at the modulation frequency.
10. The device of claim 9 , wherein the actuator comprises a distributed mode actuator and the frequency range of the coupled system is between 150 Hz to 350 Hz.
11. The device of claim 9 , wherein the actuator comprises a piezoelectric actuator and the frequency range of the coupled system is between 100 Hz to 300 Hz.
12. The device of claim 9 , wherein the actuator comprises an electromagnetic actuator and the frequency range of the coupled system is between 150 Hz to 300 Hz.
13. The device of claim 9 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises phase modulation.
14. The device of claim 9 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises pulse width modulation.
15. The device of claim 9 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises pulse rate modulation.
16. The device of claim 9 , wherein modulating the amplitude and/or frequency of the carrier wave signal comprises superimposing a plurality of carrier wave signal pulse trains of different amplitudes, phases and/or frequencies.
17. The method of claim 1 , wherein the actuator is driven while the user touches the display panel to transfer a force to the display panel, where a time domain spectrum of the transferred force comprises a pulse having a pair of peaks separated by a time period greater than a period of the carrier wave signal to provide the haptic sensation.
18. The device of claim 9 , wherein the impulse generator is configured to drive the actuator while the user touches the display panel to transfer a force to the display panel, where a time domain spectrum of the transferred force comprising a pulse having a pair of peaks separated by a time period greater than a period of the carrier wave signal to provide a haptic sensation to the user comprising a vibration at the modulation frequency.