Actuator for delivery of vibratory stimulation to an area of the body and method of application

Abstract

An actuator delivers mechanical vibrations to the body of a subject. The actuator includes a piezoelectric element, electrodes in electrical communication with an electrical source and the piezoelectric element to drive the piezoelectric element, a polymeric protective layer encapsulating the piezoelectric element and part of the electrodes, and an enclosure attached to the protective layer. The actuator includes a space between the protective layer and the enclosure allowing desired modes of vibration to develop across a surface of the protective layer that encapsulated the piezoelectric element. The actuator can include a skin attachment article that has a mounting pad for attaching to the skin of the subject and for attaching the actuator. The skin attachment article has a cover that overlies the actuator and the mounting pad when the article is attached to the skin of the subject.

Claims

1. An actuator for delivering mechanical vibrations to the body of a subject, the actuator comprising: a piezoelectric element; electrodes in electrical communication with a power source and/or a signal source and the piezoelectric element to drive the piezoelectric element; a protective layer encapsulating the piezoelectric element and at least part of the electrodes, the protective layer comprising a polymeric material; an enclosure attached to the protective layer and defining a space between the protective layer and the enclosure allowing desired modes of vibration to develop across a surface of the protective layer; and a perimeter in a top view of the protective layer is affixed to a perimeter in a top view of the enclosure thus providing mechanical lip-conditions that prevent and/or minimize motion of the piezoelectric element at its perimeter.

2. The actuator of claim 1 wherein: the enclosure includes a ventilation outlet.

3. The actuator of claim 1 wherein: an outer perimeter of the protective layer is spaced outward from an outer perimeter of the piezoelectric element.

4. The actuator of claim 1 wherein: the protective layer is a sheet laminated or glued to the piezoelectric element.

5. The actuator of claim 1 wherein: the laminated or glued sheet includes the electrodes that will deliver electric signal to the piezoelectric element.

6. The actuator of claim 1 wherein: the protective layer is surrounded by a pressure-relief apparatus.

7. The actuator of claim 1 wherein: actuation frequencies for the piezoelectric element range from 1 Hz to 4 kHz.

8. The actuator of claim 1 wherein: actuation amplitudes for the piezoelectric element range from 0.001 millimeters to 3 millimeter peak-to-peak.

9. The actuator of claim 1, further comprising: a sensor in electrical communications with a power source and/or a signal source and/or the piezoelectric element, such that that input from the sensor modifies the power and/or signal from the source to the piezoelectric element or modifies the response of the piezoelectric element to such power or signals from the source.

10. The actuator of claim 9 wherein: the sensor is selected from perfusion sensors, oxygenation sensors, piezo-film sensors, temperature sensors, photoplethysmographic sensors, strain-gauge plethysmography sensors, laser-Doppler sensors, laser-speckle sensors, infrared imaging, infrared spectography, ultrasound sensors, motion sensors, strain sensors, pressure sensors, and vibration sensors.

11. A skin attachment article for providing tissue therapy, the article comprising: a cover; a mounting pad; a connecting strip flexibly connecting the mounting pad and the cover; a first adhesive layer for attaching the article to skin of a subject with the mounting pad contacting the skin and the cover overlying the mounting pad such that an outer perimeter of the cover is spaced outward from an outer perimeter of the mounting pad; and the actuator of claim 1.

12. The article of claim 11 wherein: the mounting pad includes a third adhesive layer disposed on a top surface of the mounting pad, the third adhesive layer for attaching the actuator to the mounting pad.

13. The article of claim 11 wherein: the cover comprises a flexible material selected from wovens, non-wovens, films, gels and foams.

14. The article of claim 11 wherein: the cover comprises a perforated material, and the mounting pad comprises a perforated material.

15. The article of claim 11 wherein: the first adhesive layer is part of a separate tape that attaches the article to the skin of the subject with the mounting pad contacting the skin and the cover overlying the mounting pad.

16. The article of claim 11 further comprising: a pressure-reducing mechanism to reduce unintended pressure thus minimizing risk of pressure-ulcers and other problems developing around, near or under the article.

17. The article of claim 11 wherein: the outer perimeter of the cover is spaced outward from the outer perimeter of the mounting pad thereby defining an unobstructed path from the skin of the subject to a bottom surface of the cover between the mounting pad and the cover.

18. An actuator for delivering mechanical vibrations to the body of a subject, the actuator comprising: a piezoelectric element; electrodes in electrical communication with a power source and/or a signal source and the piezoelectric element to drive the piezoelectric element; a protective layer encapsulating the piezoelectric element and at least part of the electrodes, the protective layer comprising a polymeric material; an enclosure attached to the protective layer and defining a space between the protective layer and the enclosure allowing desired modes of vibration to develop across a surface of the protective layer; and wherein the protective layer is on all sides of the piezoelectric element in a transverse cross-sectional view, and a perimeter in a top view of the protective layer is affixed to a perimeter in a top view of the enclosure thus providing mechanical lip-conditions that prevent and/or minimize motion of the piezoelectric element at its perimeter.

19. The actuator of claim 18 wherein the protective layer is further configured for contraction and expansion corresponding to the contraction and expansion of the piezoelectric element, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an exploded perspective view of one embodiment of a device according to the invention for delivering mechanical vibrations to the body of a subject.

(2) FIG. 2 is a top plan view of an embodiment of an actuator that can be used in a device according to the invention for delivering mechanical vibrations to the body of a subject.

(3) FIG. 3 is a bottom plan view of the actuator of FIG. 2.

(4) FIG. 4 is a side elevational view of the actuator of FIG. 2.

(5) FIG. 5 is a top plan view of an adhesive patch according to the invention for securing the actuator of FIG. 2 to the body of a subject.

(6) FIG. 6 is a top plan view of the adhesive patch of FIG. 5 with the actuator of FIG. 2 secured to a mounting pad of the adhesive patch of FIG. 5.

(7) FIG. 7 is a top plan view of the adhesive patch of FIG. 5 having secured the actuator of FIG. 2 to the body of a subject.

(8) FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7 showing the adhesive patch of FIG. 5 having secured the actuator of FIG. 2.

(9) FIG. 9 is an exploded side cross-sectional view of another embodiment of a polymer-packaged piezoelectric element that can be used in a device according to the invention for delivering mechanical vibrations to the body of a subject.

(10) FIG. 10 is an exploded side cross-sectional view of yet another embodiment of a polymer-packaged piezoelectric element that can be used in a device according to the invention for delivering mechanical vibrations to the body of a subject.

(11) Like reference numerals will be used to refer to like parts from Figure to Figure in the following description of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

(12) Turning now to FIG. 1, there is shown an exploded perspective view of one example embodiment of a device 10 according to the invention for delivering mechanical vibrations to the body of a subject. The device 10 includes an enclosure 12 having a circular top wall 13 and a round side wall 14 that extends downward from the top wall 13. A central circular vent opening 16 is provided in the top wall 13. The enclosure 12 has a circular open bottom end 15. A polymer-packaged piezoelectric element 18 is placed in electrical communication with an electrical source and controller by way of a connecting electrical lead 19. The controller will normally generate specific electrical signals to drive the actuator. These signals will generate the waveform of the vibrations that may be sinusoidal, pseudo-sinusoidal, square, pulse, chain-saw or other, or combinations thereof as well as the amplitude. The polymer-packaged piezoelectric element 18 is attached to the open bottom end 15 of the enclosure 12 by adhesive, screws or any other means of attachment.

(13) Referring now to FIGS. 2, 3, 4 and 8, there is shown another non-limiting example embodiment of the device 10 (the actuator of this invention). The actuator includes a polymer-packaged piezoelectric element 18, which in turn includes a piezoelectric element in the form of a piezoelectric disk 22 having a diameter of about twenty millimeters and a thickness of about 17 mil (milli-inch). The piezoelectric element can have different shapes for its perimeter 26 such as oval, elliptical, square, rectangular, polygonal, and the like. For circular piezoelectric elements, the diameter may range from about 4 millimeters to about 100 millimeters. For oval and elliptical piezoelectric elements, the major axis may range from about 5 millimeters to about 100 millimeters. For polygonal piezoelectric elements, the length of the largest diagonal may range from about 4 millimeters to about 100 millimeters. The thickness of the piezoelectric element may range from about 2.5 mil to about 50 mil.

(14) The piezoelectric disk 22 preferably comprises a piezoelectric ceramic material that belongs to the family of lead zirconate titanate (Pb[Zr.sub.xTi.sub.1-x]O.sub.3 0x1), also called PZT. However, other suitable piezoelectric ceramic materials include lead metaniobate Pb(Nb.sub.2O.sub.6), modified lead titanate PbTi.sub.3 such as (Pb,Ca)TiO.sub.3 and (Pb,Sm)TiO.sub.3, barium titanate BaTiO.sub.3, lanthanum-doped lead zirconate titanate, and the like. Polymeric piezoelectric materials such as polyvinylidene difluoride (PVDF) are also suitable. One example piezoelectric disk 22 was formed using PZT-5A, sometimes called Navy Type II, or 3195HD. However, many other piezoelectric materials including other members of the PZT family can be used in the present invention. The surface of the piezoelectric element is normally deposited with metal or alloys including nickel, silver, copper or gold which act as electrodes. An additional set of electrodes is attached to both sides of the piezoelectric element and to a power and control unit used for delivery of electrical signals to the piezoelectric element and distribution of electricity across the piezoelectric element.

(15) The top surface 24 and the opposed bottom surface 25 of the piezoelectric disk 22 are connected to a pair of electrodes 27 which can have the same shape or different shapes. Suitable electrode materials include, without limitation, metals or alloys including copper, silver, nickel, and gold. The electrodes 27 include a ring shaped section 28 connected to a straight section 29 that is in electrical communication with the electrical lead 19. Suitable deposition techniques can be used for making the electrical connection between the piezoelectric disk 22 and the pair of electrodes 27. Multiple layers of the piezoelectric disk 22 and the pair of electrodes 27 can be used. The electrodes 27 and protective layer 31 can be configured as part of a single or double sided copper clad, flexible adhesive free polyimide dielectric laminates.

(16) An outer protective layer 31 is placed in contact with the piezoelectric disk 22 and the pair of electrodes 27 to insulate the piezoelectric disk 22 from the tissue, to protect the piezoelectric disk 22 from liquids, to provide improved resistance to mechanical failure of the piezoelectric disk 22, and to prevent direct contact of the piezoelectric disk 22 with the skin. The protective layer 31 (also called the packaging) can comprise a polymeric material selected from polyimides, polyetherketones, polyetheretherketones, polybenzimidazoles, polyphenylensulfides, silicone, polyamidimides, polysulfones, polyethersulfones, liquid crystalline polymers, and combinations thereof. In addition, more than one protective layer of polymer can be used, and different polymers or a single polymer can be used in each layer. Typically, single or double sided copper clad, flexible adhesive free polyimide dielectric laminate is glued to the piezoelectric element or elements under conditions of pressure and heat using an epoxy glue. In one form, the surface of the protective layer in touch with the skin is not smooth and has a texture to enhance a stimulatory effect.

(17) Example packaging methods include QuickPack (available from Mide Technology Corporation, Massachusetts, USA) or DuraAct (available from Physik Instrumente, Lederhose, Germany). Different packaging methods of the piezoelectric actuator can be used, some of which include polymerization directly over the piezoelectric material or use of films such as polyimide film to coat the piezoelectric material. In some embodiments, more than one layer of polymer can be used and different polymers can be used in combinations.

(18) An example version of the actuator of FIG. 3 was prepared and included a double layered piezoelectric disk 22 packaged in a polyimide layer having a total thickness of about 17 mil (by mil, we mean milli-inch, i.e., 0.001) and a diameter of about thirty millimeters. It can be seen from FIG. 3 that the perimeter 26 of the piezoelectric disk 22 in this example embodiment is spaced inward from the outer perimeter 32 of the protective layer 31. By extending the protective layer 31 outward beyond the perimeter 26 of the piezoelectric disk 22 with polyimide, we increased the generated amplitude while keeping the piezoelectric disk 22 small. The advantage is due to the mechanical properties provided by the polyimide packaging which extends beyond the diameter of the actual piezoelectric element. For a circular protective layer, the diameter may range from about 4 millimeters to about 150 millimeters. For an oval or elliptical protective layer, the major axis may range from about 5 millimeters to about 160 millimeters. For a polygonal protective layer, the length of the largest diagonal may range from about 4 millimeters to about 150 millimeters. The thickness of the protective layer on each side of the piezoelectric element may range from about 0.5 mil to about 10 mil.

(19) The actuator 10 includes an enclosure 33 having a dome shaped top wall 34 with a central circular vent opening 35. The top wall 34 of the enclosure 33 has an annular bottom surface 37 that is secured to a peripheral upper edge 39 of the protective layer 31 thus providing mechanical lip-conditions (preventing/minimizing motion of the polymer-packaged piezoelectric element 18 at the perimeter) and allowing a diaphragm-like movement at the center of the circular polymer-packaged piezoelectric element 18. The enclosure 33 can comprise a polymeric material such as polyethylene, nylon, polypropylene or other plastic martial. Alternatively, the enclosure can be a non polymeric material such as metal. The dome shaped top wall 34 of the enclosure 33 creates a free space 41 between the dome shaped top wall 34 and the piezoelectric actuator 18 so that desired vibratory modes and desired amplitudes can develop across the surface of the polymer-packaged piezoelectric element 18. The enclosure 33 preferably has the same perimeter dimensions as the protective layer 31.

(20) Turning now to FIGS. 5 to 8, a device according to the invention for delivering mechanical vibrations to the body of a subject includes an adhesive patch 50 having a top cover 52 having an oval perimeter 53 and a bottom surface 54. The cover 52 can have different shapes for its perimeter 53 such as circular, elliptical, square, rectangular, polygonal, and the like. The cover 52 has a vent opening 57. The cover 52 is made of flexible material that will conform to the shape of the actuator 10 and will fasten the actuator 10 to the skin by applying pressure over the actuator 10. Such flexible material can be woven, non-woven or made of foams, films or gels or layers such as polyurethane, polyethylene or polyvinyl chloride. The cover 52 can be breathable or not breathable and in some embodiments, it can be perforated. The bottom surface 54 of the cover 52 can be coated with an adhesive to create an adhesive structure wherein at least a portion of the bottom surface 54 is attached to the skin. Release liners can be positioned over the adhesive layer on the bottom surface 54 of the cover 52. For a circular cover 52, the diameter may range from about 10 millimeters to about 200 millimeters. For an oval or elliptical cover 52, the major axis may range from about 12 millimeters to about 250 millimeters. For a polygonal cover 52, the length of the largest diagonal may range from about 10 millimeters to about 200 millimeters. The thickness of the cover 52 may range from about 0.2 millimeters to about 3 millimeters.

(21) The adhesive patch 50 includes a mounting pad 55 having a circular perimeter 56. The mounting pad 55 can have different shapes for its perimeter 56 such as oval, elliptical, square, rectangular, polygonal, and the like. The mounting pad 55 includes a top surface 58 and an opposed bottom surface 59. The top surface 58 and the bottom surface 59 can be coated with an adhesive to create a double sided adhesive structure wherein the bottom surface 59 is attached to the skin on one side and the piezoelectric actuator 18 is attached to the top surface 58 of the mounting pad 55. The mounting pad 55 can be made of woven, nonwoven or hydrogel materials, as well as foam. The mounting pad 55 can be breathable or not breathable and in some embodiments, it can be perforated. Suitable release liners can be positioned over the adhesive layers on the top surface 58 and the bottom surface 59 of the mounting pad 55.

(22) For a mounting pad 55, the diameter may range from about 4 millimeters to about 160 millimeters. For an oval or elliptical mounting pad 55, the major axis may range from about 5 millimeters to about 170 millimeters. For a polygonal mounting pad 55, the length of the largest diagonal may range from about 4 millimeters to about 160 millimeters. The thickness of the mounting pad 55 may range from about 0.025 millimeters to about 2 millimeters.

(23) In the adhesive patch 50, the cover 52 and the mounting pad 55 are attached by a connecting strip 62. The connecting strip 62 can be in the form of an adhesive double sided flexible strip. The connecting strip 62 can help hold the mounting pad 55 and cover 52 in the right position allowing easy positioning of the cover 52 over the actuator 10. In some embodiments, the connecting strip 62 can be an integral part of the mounting pad 55 or the cover 52. In some embodiments, the connecting strip 62 can be coated with adhesive on the skin side or both sides thereby positioning the folding point of the adhesive patch 50. In some embodiments, the connecting strip 62 has no adhesive. In one embodiment, the connecting strip 62 is not included and the mounting pad 55 and the cover 52 are provided as two separate units.

(24) Referring still to FIGS. 5-8, a device according to the invention for delivering mechanical vibrations to the body of a subject can be attached to the subject as follows. In FIGS. 5 and 8, after removing any release liner, the bottom surface 59 of the mounting pad 55 is attached to the skin S of the subject by way of the adhesive on the bottom surface 59 of the mounting pad 55. In FIG. 6, after removing any release liner on the mounting pad 55, the actuator 10 is attached to the top surface 58 of the mounting pad 55 by way of the adhesive on the top surface 58 of the mounting pad 55. The adhesive patch 50 is then folded at the connecting strip 62 and the top cover 52 is attached to the actuator 10 and the skin S of the subject by way of adhesive on the bottom surface 54 of the top cover 52. The device according to the invention for delivering mechanical vibrations to the body of a subject is therefore attached to the skin S of the subject as shown in FIGS. 7 and 8.

(25) In a different embodiments other attachment mechanisms can be used such as placing the actuator under compression wrap, stretchable hook and loop fastener strap sold under the name Velcro, bandage or other means of attachment that will result in direct contact of the actuator surface with a tissue.

(26) Turning to FIG. 9, there is shown an exploded side cross-sectional view of another embodiment of a polymer-packaged piezoelectric element 70 that can be used in a device according to the invention for delivering mechanical vibrations to the body of a subject. The polymer-packaged piezoelectric element 70 includes a single sided copper clad flexible adhesiveless polyimide dielectric laminate 71 with copper electrodes 71e. The laminate 71 is attached by an epoxy glue layer 72 to one side of a first piezoelectric element 73. The first piezoelectric element 73 preferably comprises a piezoelectric ceramic material as used in the piezoelectric disk 22 described above. An epoxy glue layer 74 attaches one side of a double sided copper clad flexible adhesiveless polyimide dielectric laminate 75 to an opposite side of the first piezoelectric element 73. The laminate 75 has copper electrodes 75e. An epoxy glue layer 76 attaches an opposite side of the double sided copper clad flexible adhesiveless polyimide dielectric laminate 75 to one side of a second piezoelectric element 77. An epoxy glue layer 78 attaches an opposite side of the second piezoelectric element 77 to a single sided copper clad flexible adhesiveless polyimide dielectric laminate 79. The laminate 79 has copper electrodes 79e. One non-limiting example polymer-packaged piezoelectric element 70 has a thickness of 17 mils.

(27) Turning to FIG. 10, there is shown an exploded side cross-sectional view of yet another embodiment of a polymer-packaged piezoelectric element 80 that can be used in a device according to the invention for delivering mechanical vibrations to the body of a subject. The polymer-packaged piezoelectric element 80 includes a single sided copper clad flexible adhesiveless polyimide dielectric laminate 81 that is attached by an epoxy glue layer 82 to one side of a piezoelectric element 83. The laminate 81 has copper electrodes 81e. The piezoelectric element 83 preferably comprises a piezoelectric ceramic material as used in the piezoelectric disk 22 described above. An epoxy glue layer 84 attaches an opposite side of the piezoelectric element 83 to a single sided copper clad flexible adhesiveless polyimide dielectric laminate 85.

(28) Although the invention has been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the scope of the appended claims should not be limited to the description of the embodiments contained herein.