Ultrasonic vibrator
View Patent ↗A mobile device including a casing, a signal generator housed within the casing, for generating signals, at least one speaker housed within the casing and coupled with the signal generator, for producing sound from a signal generated by said signal generator, wherein the sound produced by the at least one speaker is (i) substantially inaudible, and (ii) vibrates the casing at a frequency approximately equal to a resonant frequency of the casing.
1. A mobile electronic device comprising:
a casing;
a signal generator housed within said casing, for generating a signal that is a composite of at least two harmonics, each of which has a frequency higher than the human audible range, wherein the difference in frequencies for two of the at least two harmonics is approximately equal to the resonant frequency of said casing;
at least one speaker housed within said casing and coupled with said signal generator, for producing sound from a signal generated by said signal generator,
wherein the sound produced by said at least one speaker is (i) substantially inaudible, and (ii) vibrates said casing at a frequency approximately equal to a resonant frequency of said casing.
2. The mobile electronic device of claim 1 wherein the at least two harmonics each has a frequency in the range of 20-30 KHz.
3. The mobile electronic device of claim 1 wherein the difference in frequencies for two of the at least two harmonics is in the range of 20-50 Hz.
4. The mobile electronic device of claim 1 , wherein the device does not comprise a rotating motor.
5. The mobile electronic device of claim 1 wherein the signal generated by said signal generator is of the form
S ( t )=sin(2 πf h t )+sin(2π( f h +f r ) t ),
where the frequencies f h and f h +f r are above the human audible range and within the response range of said at least one speaker.
6. The mobile electronic device of claim 5 wherein the frequency f r is of the form
f r =f m +A sin(2 πf s t ),
where f m is a middle frequency, A is a half-range amplitude, and f s is a sweep increment that is significantly below the resonant frequency of said casing.
7. The mobile electronic device of claim 6 wherein the resonant frequency of said casing is within the range f m −A to f m +A.
8. The mobile electronic device of claim 1 further comprising a baseband processor that comprises said signal generator.
9. The mobile electronic device of claim 8 further comprising a power subsystem coupled with said baseband processor.