Touch sensitive device
A method of making a touch-sensitive data entry screen of the kind arranged to provide haptic response to a user via at least one electromechanical exciter coupled to the screen, comprising analyzing the mechanical and electromechanical coupled system represented by the data entry screen and the at least one exciter, and selecting values of parameters of the coupled system to provide a required displacement and acceleration of the screen at low frequency in response to human touch.
1. An apparatus, comprising:
a frame;
a touch panel mounted in the frame with a rear surface facing a surface of the frame;
a suspension mechanically coupled to the touch panel, the suspension separating the rear surface of the touch panel from the surface of the frame facing the rear surface, the touch panel and suspension forming a coupled system having a resonant frequency at a frequency suitable for supplying a haptic response to a user;
a sensor coupled to the touchscreen to detect a user's touch of the touchscreen during use of the apparatus; and
at least one electromechanical exciter mechanically coupled to the rear surface of the touch panel,
wherein an internal resonance of the electromechanical exciter substantially coincides with the resonant frequency of the coupled system.
2. The apparatus of claim 1 , wherein the apparatus comprises a plurality of electromechanical exciters coupled to the rear surface of the touch panel at different locations.
3. The apparatus of claim 1 , wherein the apparatus comprises a transducer coupled to the rear surface of the touch panel.
4. The apparatus of claim 1 , wherein the touch panel has a dimension of at least 200 mm.
5. The apparatus of claim 1 , wherein the touch panel has a mass of at least 200 gms.
6. The apparatus of claim 1 , wherein the at least one electromechanical exciter provides sufficient force to the touchscreen to produce an acceleration of the touchscreen in a range from 5 m/s 2 to 50 m/s 2 during use of the apparatus.
7. The apparatus of claim 1 , wherein the at least one electromechanical exciter is an inertial exciter.
8. The apparatus of claim 1 , wherein the at least one electromechanical exciter is a grounded exciter.
9. The apparatus of claim 1 , wherein the frame is a grounded frame extending around a periphery of the touchscreen.
10. The apparatus of claim 1 , further comprising a processor in communication with the sensor and configured to obtain information about a user's touch of the touchscreen from the sensor during operation of the apparatus.
11. The apparatus of claim 10 , further comprising a signal generator in communication with the processor, the signal generator being configured to direct haptic signals to the at least one electromechanical exciter in response to a user's touch of the touchscreen detected by the sensor during use of the apparatus.
12. The apparatus of claim 11 , wherein the signal generator comprises an amplifier.
13. The apparatus of claim 12 , wherein the amplifier is a switching amplifier.
14. The apparatus of claim 11 , a wherein the haptic signal comprises a low pass filtered waveform from the signal generator.
15. The apparatus of claim 1 , wherein the apparatus comprises a bending mode loudspeaker.
16. The apparatus of claim 1 , wherein the apparatus is an electronic display.