Touch Sensitive Device

Abstract

A touch sensitive device comprising a panel capable of supporting bending waves, a user-accessible touch sensitive screen on or forming part of a face of the panel, the touch sensitive screen having a plurality of different sensing areas, a plurality of vibration exciters coupled to the panel to apply bending waves to the panel to provide tactile feedback at the plurality of sensing areas in response to the user touching a sensing area, and signal processing means arranged to apply signals to the vibration exciters so as to steer bending waves applied to the panel by the plurality of vibration exciters whereby the amplitude of the applied bending waves is maximised at the sensing area touched by the user and reduced or minimised at each other sensing area.

What is claimed is: 
     
         1 . A touch sensitive device comprising:
 a panel capable of supporting bending waves,   a user-accessible touch sensitive screen on or forming part of a face of the panel, the touch sensitive screen having a plurality of different sensing areas,   a plurality of vibration exciters coupled to the panel to apply bending waves to the panel to provide tactile feedback at at least one of the plurality of sensing areas in response to the user touching at least one sensing area, and   a signal generator and signal processor configured to determine and apply signals to the vibration exciters so as simultaneously to provide tactile feedback at a plurality of the sensing areas and to apply bending wave signals having small or minimal acoustic component to steer bending waves applied to the panel by the plurality of vibration exciters whereby the amplitude of the applied bending waves is maximized at the sensing area touched by the user and reduced or minimized at each other sensing area with small or minimal acoustic component.   
     
     
         2 . The touch sensitive device of  claim 1 , wherein the signal processor is configured to determine and apply bending wave signals having a small or minimal acoustic component. 
     
     
         3 . The touch sensitive device of  claim 1 , comprising n number of signal sensing areas and n+1 number of vibration exciters. 
     
     
         4 . The touch sensitive device of  claim 1 , wherein the panel is intendedly resonant and wherein the signals applied by the vibration exciters cause the panel to resonate. 
     
     
         5 . The touch sensitive device of  claim 4 , wherein the signal steering is such that the signal sensing area touched by the user is caused to be antinodal and each other signal sensing area is caused to be nodal. 
     
     
         6 . The touch sensitive device of  claim 1 , wherein the vibration exciters are spaced apart around the panel. 
     
     
         7 . The touch sensitive device of  claim 6 , wherein the vibration exciters are positioned at the periphery of the panel. 
     
     
         8 . The touch sensitive device of  claim 1 , wherein the signal processor is configured to control at least one of the timing, phase and frequency of the signal to each vibration exciter. 
     
     
         9 . A method of operating a touch sensitive device comprising a panel capable of supporting bending waves, a user-accessible touch sensitive screen on or forming part of a face of the panel, the touch sensitive screen having a plurality of different sensing areas, a plurality of vibration exciters coupled to the panel to apply bending waves to the panel to provide tactile feedback at the plurality of sensing areas in response to the user touching a sensing area, and a signal generator and signal processor configured to determine and apply signals to the vibration exciters so as to steer bending waves applied to the panel by the plurality of vibration exciters whereby the amplitude of the applied bending waves is maximized at the sensing area touched by the user and reduced or minimized at each other sensing area, the method comprising the steps of:
 sensing at least one area of the screen touched by a user and   processing and applying signals to the plurality of vibration exciters so as simultaneously to provide tactile feedback at a plurality of the sensing areas and to apply bending wave signals having small or minimal acoustic component and to steer bending waves in the panel whereby the amplitude of vibration is maximized at the at least one sensing area touched by the user and reduced or minimized at each other sensing area with small or minimal acoustic component.   
     
     
         10 . The method of  claim 9 , further comprising the step of processing the signals applied to the vibration exciters so as simultaneously to provide tactile feedback to a plurality of sensing areas while reducing or minimizing crosstalk between the sensing areas. 
     
     
         11 . The method of  claim 9 , wherein the signal processing comprises n number of signal sensing areas and at least n+1 number of vibration exciters. 
     
     
         12 . The method of  claim 9 , wherein the panel is intendedly resonant and wherein the method further comprises the step of applying signal with the vibration exciters to cause the panel to resonate. 
     
     
         13 . The method of  claim 9 , further comprising the step of steering the signals so that the signal sensing area touched by the user is caused to be antinodal and each other signal sensing area is caused to be nodal. 
     
     
         14 . The method of  claim 13 , wherein the steering comprises adjusting at least one of the timing, phase and frequency of the signals to at least two vibration exciters to control the position on the panel where travelling waves from the at least two vibration exciters intersect, and so that travelling waves from the at least two vibration exciters are at a coincident amplitude maximum at the position of intersection. 
     
     
         15 . The method of  claim 9 , further comprising the step of applying signals to the vibration exciters so as simultaneously to provide tactile feedback at a plurality of the sensing areas.