Touch Sensitive Device

Abstract

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 of generating a desired haptic sensation in a coupled system comprising a touch surface and a force exciter or actuator coupled to the touch surface, the method comprising generating a carrier wave signal at frequencies within the frequency bandwidth of the coupled system, modulating the earner 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 the desired haptic sensation and driving the exciter or actuator with the modulated earner wave signal to excite the touch surface whereby the desired haptic sensation is perceived at a frequency below the frequency bandwidth of the coupled system is simulated to a user touching the touch surface. 
     
     
         2 . The method of  claim 1 , wherein the system comprises a distributed mode actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 150 Hz to 350 Hz. 
     
     
         3 . The method of  claim 1 , wherein the system comprises a piezoelectric actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 100 Hz to 300 Hz. 
     
     
         4 . The method of  claim 1 , wherein the system comprises an electromagnetic actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 150 Hz to 300 Hz. 
     
     
         5 . The method of  claim 1 , wherein the system comprises an actuator providing a frequency bandwidth for the coupled system in the region of 100 Hz to 400 Hz with a high Bl or force factor. 
     
     
         6 . The method of  claim 1 , wherein the complex modulation comprises frequency modulation. 
     
     
         7 . The method of  claim 1 , wherein the complex modulation comprises phase modulation. 
     
     
         8 . The method of  claim 1 , wherein the complex modulation comprises pulse width modulation. 
     
     
         9 . The method of  claim 1 , wherein the complex modulation comprises pulse rate modulation. 
     
     
         10 . 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. 
     
     
         11 . The device of  claim 10  comprising a distributed mode actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 150 Hz to 350 Hz. 
     
     
         12 . The device of  claim 10  comprising a piezoelectric actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 100 Hz to 300 Hz. 
     
     
         13 . The device of  claim 10  comprising an electromagnetic actuator having a frequency bandwidth for the coupled system with a lower limit in the region of 150 Hz to 300 Hz. 
     
     
         14 . The device of  claim 10 , comprising an actuator providing a frequency bandwidth for the coupled system in the region of 100 Hz to 400 Hz with a high Bl or force factor.