IP Library › Granted Patent US 7,608,984
Granted Patent B2
US 7,608,984 · App. 11/747,469 · Granted Oct 27, 2009

Motion amplification using piezoelectric element

View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 7,608,984
App. No.
11/747,469
Granted
Oct 27, 2009
Kind
B2
Abstract

A motion amplifier ( 22 ) comprises piezoelectric diaphragm ( 30 ) and drive electronics ( 26 ) for applying a drive signal to the piezoelectric diaphragm. The motion amplifier preferably comprises (in addition to the piezoelectric diaphragm) a reaction mass ( 34 ) connected to the piezoelectric diaphragm; a reacted mass ( 40 ) connected to the piezoelectric diaphragm; and, a reacted mass spring ( 50, 270 ) for resiliently carrying the reacted mass. Motion or displacement of the piezoelectric diaphragm ( 30 ) is amplified to produce a greater displacement or motion of an actuator region or surface ( 46 ) of the reacted mass ( 40 ).

Claims (75)

1. A motion amplifier comprising:

a piezoelectric diaphragm;

a reaction mass connected to the piezoelectric diaphragm;

a reacted mass connected to the piezoelectric diaphragm;

a reacted mass spring for resiliently carrying the reacted mass;

wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass;

wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity.

2. The apparatus of claim 1 , further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm.

3. The apparatus of claim 2 , wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency.

4. The apparatus of claim 3 , wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f 2 , wherein the predetermined frequency is f 2 , and wherein the drive signal is generated to urge the motion amplifier to the frequency f 2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier.

5. The apparatus of claim 4 , wherein the resonant frequency f 2 is related to a spring constant K 2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass.

6. The apparatus of claim 2 , wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier.

7. The apparatus of claim 6 , wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier.

8. The apparatus of claim 1 , further comprising:

an amplifier base; and

means for resiliently mounting the amplifier base relative to the outside world.

9. The apparatus of claim 8 , wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring.

10. The apparatus of claim 9 , wherein the reacted mass spring comprises a corrugated diaphragm.

11. The apparatus of claim 1 , further comprising a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring.

12. The apparatus of claim 11 , wherein the bellows assembly further comprises an amplifier base, and further comprising means for resiliently mounting the amplifier base relative to the outside world.

13. A motion amplifier comprising:

a piezoelectric diaphragm;

a reaction mass connected to the piezoelectric diaphragm;

a reacted mass connected to the piezoelectric diaphragm;

a reacted mass spring for resiliently carrying the reacted mass;

wherein the reacted mass spring comprises a corrugated diaphragm;

wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity.

14. The apparatus of claim 13 , wherein the corrugated diaphragm has corrugations proximate a circumference of the diaphragm.

15. The apparatus of claim 13 , wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass.

16. The apparatus of claim 13 , further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm.

17. The apparatus of claim 16 , wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency.

18. The apparatus of claim 17 , wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f 2 , wherein the predetermined frequency is f 2 , and wherein the drive signal is generated to urge the motion amplifier to the frequency f 2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier.

19. The apparatus of claim 18 , wherein the resonant frequency f 2 is related to a spring constant K 2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass.

20. The apparatus of claim 16 , wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier.

21. The apparatus of claim 20 , wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier.

22. The apparatus of claim 13 , further comprising:

an amplifier base to which the reacted mass spring is attached; and

means for resiliently mounting the amplifier base relative to the outside world.

23. The apparatus of claim 22 , wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring.

24. A motion amplifier comprising:

a piezoelectric diaphragm;

a reaction mass connected to the piezoelectric diaphragm;

a reacted mass connected to the piezoelectric diaphragm;

a reacted mass spring for resiliently carrying the reacted mass;

a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring;

wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity.

25. The apparatus of claim 24 , wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass.

26. The apparatus of claim 24 , further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm.

27. The apparatus of claim 26 , wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency.

28. The apparatus of claim 27 , wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f 2 , wherein the predetermined frequency is f 2 , and wherein the drive signal is generated to urge the motion amplifier to the frequency f 2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier.

29. The apparatus of claim 28 , wherein the resonant frequency f 2 is related to a spring constant K 2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass.

30. The apparatus of claim 27 , wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier.

31. The apparatus of claim 30 , wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier.

32. The apparatus of claim 24 , further comprising:

an amplifier base connected to the reacted mass spring; and

means for resiliently mounting the amplifier base relative to the outside world.

33. The apparatus of claim 32 , wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring.

34. A motion amplifier comprising:

a piezoelectric diaphragm;

a reaction mass connected to the piezoelectric diaphragm;

a reacted mass connected to the piezoelectric diaphragm;

a reacted mass spring for resiliently carrying the reacted mass;

an amplifier base connected to at least one of the reacted mass and the reacted mass spring;

means for resiliently mounting the amplifier base relative to the outside world;

wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity.

35. The apparatus of claim 34 , wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass.

36. The apparatus of claim 34 , further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm.

37. The apparatus of claim 36 , wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency.

38. The apparatus of claim 37 , wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f 2 , wherein the predetermined frequency is f 2 , and wherein the drive signal is generated to urge the motion amplifier to the frequency f 2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier.

39. The apparatus of claim 38 , wherein the resonant frequency f 2 is related to a spring constant K 2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass.

40. The apparatus of claim 36 , wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier.

41. The apparatus of claim 40 , wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier.

42. The apparatus of claim 34 , wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring.

43. The apparatus of claim 34 , wherein the reacted mass spring comprises a corrugated diaphragm.

44. The apparatus of claim 34 , further comprising a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring.