Thermoacoustic module, thermoacoustic device, and method for making the same

1. A thermoacoustic module, the thermoacoustic module comprising:

a substrate having a top surface, and the top surface defining at least one recess;

a sound wave generator comprising at least one first region suspended above the at least one recess and at least one second region in contact with the top surface of the substrate; and

at least one first electrode and at least one second electrode coupled to the sound wave generator;

wherein the sound wave generator is capable of generating sound by converting electrical signal into heat, transferring the heat to a medium, and causing a thermoacoustic effect.

2. The thermoacoustic module of claim 1 , wherein the sound wave generator comprises a carbon nanotube structure, the carbon nanotube structure comprises at least one carbon nanotube film.

3. The thermoacoustic module of claim 2 , wherein the at least one carbon nanotube film comprises a plurality of successive carbon nanotubes joined end-to-end by van der Waals attractive force therebetween, the plurality of carbon nanotubes in the at least one carbon nanotube film are substantially aligned along a single direction and substantially parallel to a surface of the at least one carbon nanotube film.

4. The thermoacoustic module of claim 3 , wherein the carbon nanotubes are oriented along a direction from the at least one first electrode to the at least one second electrode.

5. The thermoacoustic module of claim 2 , wherein the at least one carbon nantoube film comprises a plurality of long, curved, disordered carbon nanotubes entangled with each other.

6. The thermoacoustic module of claim 1 , wherein the sound wave generator comprises of a carbon nanotube composite structure, the carbon nanotube composite structure comprises of:

at least one carbon nanotube film, the at least on carbon nanotube film comprises of a plurality of carbon nanotubes; and

a conductive material.

7. The thermoacoustic module of claim 1 , wherein the heat capacity per unit area of the sound wave generator is less than 2×10 −4 J/cm 2 *K.

8. The thermoacoustic module of claim 1 , wherein the at least one recess is a though groove, a through hole, a blind groove, or a blind hole.

9. The thermoacoustic module of claim 1 , wherein the at least one recess is a blind groove or a blind hole with a depth ranging from about 10 microns to about 10 millimeters from the top surface.

10. The thermoacoustic module of claim 1 , wherein the substrate comprises a plurality of recesses, the recesses are through grooves being parallel to each other and being equidistant apart.

11. The thermoacoustic module of claim 1 , wherein the at least one first electrode comprises of a plurality of first electrodes and the at least one second electrode comprises of a plurality of second electrodes.

12. The thermoacoustic module of claim 11 , wherein the plurality of first electrodes and the plurality of second electrodes are substantially parallel to each other and arranged in a staggered manner.

13. A thermoacoustic device, the thermoacoustic device comprising:

a thermoacoustic module comprising:

a substrate comprising a top surface, and the top surface defining at least one recess; and

a sound wave generator comprising at least one first region suspended above the at least one recess and at least one second region in contact with the top surface of the substrate; and

an signal input device capable of transmitting signals to the sound wave generator;

wherein the sound wave generator is capable of generating sound by converting electrical signal into heat, transferring the heat to a medium, and causing a thermoacoustic effect.

14. The thermoacoustic module of claim 13 , wherein the signal input device is an electrical signal input device connected to the sound wave generator through at least one first electrode and at least one second electrode.

15. The thermoacoustic module of claim 13 , wherein the signal input device is an electromagnetic wave device capable of sending electromagnetic waves to the sound wave generator.

16. The thermoacoustic module of claim 13 , wherein the sound wave generator comprises at least one carbon nanotube film, the at least one carbon nanotube film comprises of a plurality of successive carbon nanotubes joined end-to-end by van der Waals attractive force therebetween, the carbon nanotubes in the carbon nanotube film are substantially aligned along a single direction.

17. The thermoacoustic module of claim 15 , wherein the electromagnetic wave device is a laser-producing device, a light source, or an electromagnetic signal generator.

18. The thermoacoustic module of claim 13 , wherein the recess is a though groove, a through hole, a blind groove, or a blind hole.

19. A thermoacoustic device, the thermoacoustic device comprising:

a thermoacoustic module comprising:

a substrate having a top surface and at least one recess;

a sound wave generator comprising at least one first region suspended above the at least one recess and at least one second region in contact with the top surface of the substrate;

at least one first electrode and at least one second electrode coupled to the sound wave generator; and

a cover board; and

two fixing frames, wherein the thermoacoustic module is located between the two fixing frames;

wherein the sound wave generator is capable of generating sound by converting electrical signal into heat, transferring the heat to a medium, and causing a thermoacoustic effect.

20. The thermoacoustic device of claim 19 , wherein the heat capacity per unit area of the sound wave generator is less than 2×10 −4 J/cm 2 *K.