Piezoelectric speaker

1. A piezoelectric speaker, comprising:

a cover with a receiving space;

a vibrating speaker unit accommodated in the receiving space, including a piezoelectric oscillator including an upper surface and an lower surface, a diaphragm disposed on the upper surface of the piezoelectric oscillator, and a vibrating member kept a distance from the lower surface of the piezoelectric oscillator; wherein

the piezoelectric oscillator defines a first amplitude capable of driving the diaphragm only and a second amplitude driving both the vibrating member to vibrating with a largest amplitude and the diaphragm to generate sound, the distance is larger than the first amplitude and smaller than the second amplitude.

2. The piezoelectric speaker as described in claim 1 , wherein the cover defines an upper cover and a lower cover, the upper cover defines an upper wall with a number of sound holes and a pair of first conductive holes.

3. The piezoelectric speaker as described in claim 2 , wherein the lower cover defines a lower wall with a number of through holes and a pair of second conductive holes.

4. The piezoelectric speaker as described in claim 3 , wherein the vibrating member includes a bracket with a main body, a protruding portion extending upwards from an upper face of the main body, and a supporting portion including a number of columns extending downwards from a lower face of the main body and passing through the through holes of the lower wall.

5. The piezoelectric speaker as described in claim 4 , wherein the vibrating member defines a plurality of springs nested around the columns and disposed between a lower face of the main body of the bracket and an upper face of the lower wall.

6. The piezoelectric speaker as described in claim 5 , wherein the diaphragm is disposed between the upper cover and the piezoelectric oscillator.

7. The piezoelectric speaker as described in claim 6 , wherein the diaphragm and the piezoelectric oscillator divide the receiving space into a first cavity and a second cavity.

8. The piezoelectric speaker as described in claim 7 , wherein the piezoelectric oscillator defines a number of overlapping piezoelectric plates made from piezoelectric material, a pair of positive pole plates dispose at two surfaces of one end of the piezoelectric oscillator, and a pair of negative pole plates disposed at two surfaces of the other end of the piezoelectric oscillator.

9. The piezoelectric speaker as described in claim 8 , wherein the piezoelectric speaker defines a controller outside providing electrical signals via a number of electrical wires passing through the first and second conductive holes to connect with the positive pole plates and the negative pole plates.

10. A piezoelectric speaker, comprising:

a cover with a receiving space;

a vibrating speaker unit accommodated in the receiving space, including a piezoelectric oscillator including an upper surface and an lower surface, a diaphragm attached to the upper surface of the piezoelectric oscillator, and a vibrating member attached the lower surface of the piezoelectric oscillator; wherein

vibration of the piezoelectric oscillator with any amplitude is capable of driving the diaphragm to generate sound and the vibrating member to vibrate; wherein the vibrating member includes a bracket with a main body, a protruding portion extending upwards from an upper face of the main body, and a supporting portion including a number of columns extending downwards from a lower face of the main body.

11. The piezoelectric speaker as described in claim 10 , wherein the cover defines an upper cover and a lower cover, the upper cover defines an upper wall with a number of sound holes and a pair of first conductive holes, the lower cover defines a lower wall with a number of through holes and a pair of second conductive holes.

12. The piezoelectric speaker as described in claim 11 , wherein the number of columns extending downwards from the lower face of the main body and passing through the through holes of the lower wall.

13. The piezoelectric speaker as described in claim 12 , wherein the vibrating member defines a plurality of springs nested around the columns and disposed between a lower face of the main body of the bracket and an upper face of the lower wall.

14. The piezoelectric speaker as described in claim 13 , wherein the diaphragm is disposed between the upper cover and the piezoelectric oscillator, the diaphragm and the piezoelectric oscillator divide the receiving space into a first cavity and a second cavity.

15. The piezoelectric speaker as described in claim 14 , wherein the piezoelectric oscillator defines a number of overlapping piezoelectric plates made from piezoelectric material, a pair of positive pole plates dispose at two surfaces of one end of the piezoelectric oscillator, and a pair of negative pole plates disposed at two surfaces of the other end of the piezoelectric oscillator.

16. The piezoelectric speaker as described in claim 15 , wherein the piezoelectric speaker defines a controller outside providing electrical signals via a number of electrical wires passing through the first and second conductive holes to connect with the positive pole plates and the negative pole plates.

17. A piezoelectric speaker, comprising:

an upper cover with a number of sound holes;

a lower cover with a number of through holes;

a piezoelectric oscillator disposed between the upper cover and the lower cover;

a diaphragm disposed on an upper surface of the piezoelectric oscillator;

a vibrating member disposed under the piezoelectric oscillator; wherein

the vibrating member defines a main body, a protruding portion extending upwards from the main body, a supporting portion extending downwards from the main body and passing through the through holes of the lower cover, and a spring assemble to the supporting portion for the vibrating member capable of moving up and down.

18. The piezoelectric speaker as described in claim 17 , wherein the spring is limited between the main body and the lower cover.

19. The piezoelectric speaker as described in claim 18 , wherein the protruding portion is capable of elastically engaged with a bottom surface of the piezoelectric oscillator.

20. The piezoelectric speaker as described in claim 18 , wherein the protruding portion is attached to a bottom surface of the piezoelectric oscillator.