PRESSURE WAVE TRANSDUCER

Abstract

A system and method for producing pressure waves accelerating a projectile membrane in response to a pulse of force produced by a power source. The accelerating membrane delivers kinetic energy to a target membrane upon collision. Following the collision, the power source may continue to deliver additional energy to the now-in-contact membranes. The kinetic energy of the impact and the additional energy following the impact contribute to producing pressure waves by the target membrane.

Claims

1. A system comprising: a projectile membrane and a target membrane initially spaced from said projectile membrane by a gap; and a power source operative to produce a force to accelerate said projectile membrane towards said target membrane, the force causing said projectile membrane to travel over said gap and impact said target membrane with an impact force that transfers kinetic energy to said target membrane and to said target membrane, said target membrane being configured to deliver acoustic pressure pulses to an object.

2. The system according to claim 1, wherein said target membrane contacts said object.

3. The system according to claim 1, wherein said target membrane does not contact said object.

4. The system according to claim 1, further comprising a biasing device configured to move said projectile membrane back to its initial position.

5. The system according to claim 1, further comprising an array of more than one said projectile membrane and more than one said target membrane.

6. The system according to claim 5, further incorporating a sequencer operable to sequence force pulses corresponding to the more than one said projectile membrane.

7. The system according to claim 1, wherein at least one said power source produces the force to accelerate said projectile membranes towards said target membranes.

8. A method comprising: providing at least one transducer, each transducer comprising a projectile membrane and a target membrane initially spaced from said projectile membrane by a gap, and a power source operative to produce a force to accelerate said projectile membrane towards said target membrane, the force causing said projectile membrane to travel over said gap and impact said target membrane with an impact force that transfers kinetic energy to said target membrane and creates a pressure pulse at said target membrane, said target membrane being configured to deliver acoustic pressure pulses to an object.

9. The method according to claim 8, comprising using said at least one transducer to deliver acoustic pressure pulses to the object.

10. The method according to claim 8, wherein a time duration of the force applied to said projectile membrane is longer than a time required for said projectile membrane to reach said target membrane.

11. The method according to claim 10, wherein a remainder of the force which is still applied to said projectile membrane following the impact creates an additional pressure on said projectile membrane, and said additional pressure is transferred to said target membrane which is already in contact with said projectile membrane.

12. The method according to claim 10, comprising modifying pressure on said target membrane by modifying materials of said membranes.

13. The method according to claim 10, comprising modifying pressure on said target membrane by modifying a magnitude of the initial gap between the membranes.

14. The method according to claim 10, comprising modifying pressure on said target membrane by modifying a force pulse produced by the power source.

15. The method according to claim 8, comprising using said more than one transducer arranged in an array to deliver acoustic pressure pulses to the object.

16. The method according to claim 15, comprising using said array to deliver converging acoustic pressure pulses to the object.

17. The method according to claim 15, comprising using said array to deliver diverging acoustic pressure pulses to the object.

18. The method according to claim 15, comprising using said array to deliver planar acoustic pressure pulses to the object.

19. The method according to claim 15, comprising moving at least one of said transducers of said array with respect to another one of said transducers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

[0015] FIGS. 1 and 2 are simplified illustrations of a system (transducer) for pressure wave generation or treatment, constructed and operative in accordance with an embodiment of the invention, showing a projectile membrane prior to and after impacting a target membrane, respectively.

[0016] FIG. 3 is a simplified illustration of an array of such transducers, constructed and operative in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0017] Reference is now made to FIG. 1, which illustrates a system 10 for producing acoustic pressure pulses or shockwaves, constructed and operative in accordance with a non-limiting embodiment of the invention.

[0018] System (also referred to as transducer) 10 includes a projectile membrane 12 and a target membrane 14 initially spaced from projectile membrane 12 by a gap 16 (such as but not limited to, 2 mm or less). A power source 18 is operative to produce a force F to accelerate projectile membrane 12 towards target membrane 14. The force causes projectile membrane 12 to travel over gap 16 and impact target membrane 14 with an impact force that transfers kinetic energy to target membrane 14 and creates a pressure pulse at target membrane 14. Target membrane 14 is operable to deliver acoustic pressure pulses to an object 20, such as tissue. In one embodiment, target membrane 14 contacts object 20; in other embodiments, target membrane 14 does not necessarily contact object 20 (in which case, the wave front can be modified by reflectors, lenses, etc., prior to coupling to the patient).

[0019] The power source 18 may include, without limitation, electromagnetic, pneumatic, piezoelectric, electrohydraulic, ballistic, pyrotechnic and others. For an inductive electromagnetic power source, the projectile membrane 12 may be electrically conductive so that the electromagnetic power source induces a magnetic force that repels projectile membrane 12 (the target membrane may be non-conductive).

[0020] Projectile membrane 12 may move back to its initial position simply by gravitation or by means of a biasing device 22, such as but not limited to, a spring, damper, electromagnetic device (e.g., the electromagnetic power source is switched to attract the membrane 12), or pneumatic device.

[0021] The membranes may be of any size or shape, such as but not limited to, circular, rectangular, square, or polygonal or others and any combination thereof. The membranes may be planar, concave or convex and any combination thereof.

[0022] In one embodiment, the time duration of the force applied to projectile membrane 12 may be longer than the time required for the projectile membrane 12 to reach the target membrane 14. In such a case, the remaining part of the force which is still applied to the projectile membrane 12 following the impact creates an additional pressure on projectile membrane 12, which pressure is transferred to the target membrane 14 which is already in contact with the projectile membrane 12. The resulting pressure on the target membrane 14 is a combination of the ballistic component of the projectile membrane 12 up to contact with (impact on) the target membrane 12 the additional component due to the energy applied to the projectile membrane 12 during the time after the initial impact.

[0023] The magnitude of the ballistic component is a function, inter alia, of the coefficient of restitution of the materials of both membranes (that is, relative speed after impact divided by relative speed before impact). The additional component is a function, inter alia, of the acoustic impedances of both membranes. The combined pressure on the target membrane 14 may be optimized or modified by selecting the membrane materials, selecting the magnitude of the initial gap between the membranes, selecting the shape of the force pulse produced by the power source, and other factors.

[0024] The system may include more than one such transducer arranged in any suitable array. The transducer array may be arranged to produce combined waves that are converging, diverging or planar. One power source may be used or a plurality of power sources, such as one power source dedicated to each projectile membrane. The power source or sources may energize the transducers of the array at different times to produce different pressure waves and effects. The transducers of the array may be movable with respect to each other to produce different combined pressure waves and effects.