Integrated piezoelectric-driven vibrating beams applicable to hand-held surgical devices

Abstract

A piezo-driven, vibrating beam is applicable to surgical procedures. A rod of piezoelectric material defines a length with proximal and distal ends. A pattern of electrodes, disposed adjacent to and along the length of the rod of piezoelectric material, is adapted for connection to a generator operative to stimulate the piezoelectric material, causing the rod to assume one or more vibratory states. In preferred embodiments, the proximal end of the rod of piezoelectric material is adapted for coupling to a blocking mass causing the vibratory states to be concentrated at the distal end of the rod of piezoelectric material. The pattern of electrodes may comprise interdigitated fingers, and the system may further include a material encapsulating the rod and the pattern of electrodes. Preferred embodiments may further include a plurality of coextensive, parallel rods forming a basic unit, each rod having a separate pattern of electrodes adjacent thereto.

Claims

1. A vibrating beam applicable to surgical procedures, comprising: a sheet of dielectric material; an elongated pattern of interdigitated electrodes deposited on the sheet of dielectric material; a flexible, bendable elongated rod of piezoelectric material having a length with proximal and distal ends; wherein the rod of piezoelectric material is bonded to the dielectric material such that the pattern of electrodes is disposed adjacent to and coextensively along the length of the rod of piezoelectric material; and wherein the pattern of electrodes is adapted for connection to a generator operative to stimulate the piezoelectric material, causing the rod to assume one or more vibratory states.

2. The vibrating beam of claim 1, further including a blocking mass coupled to the proximal end of the rod of piezoelectric material causing the vibratory states to be concentrated at the distal end of the rod of piezoelectric material.

3. The vibrating beam of claim 1, wherein the piezoelectric material is PZT (lead zirconate titanate).

4. The vibrating beam of claim 1, wherein: the sheet of backing material is wider than the elongated rod; and the sheet of backing material is folded around the rod so as to encapsulate the rod and the pattern of electrodes.

5. The vibrating beam of claim 1, further including a plurality of coextensive, parallel rods bonded to the backing material forming a basic unit, each rod having a separate pattern of electrodes adjacent thereto.

6. The vibrating beam of claim 5, further including four coextensive, parallel rods forming a basic unit; wherein each rod has a rectangular cross section; and wherein a cross section of the basic unit shows two rows of two rods.

7. The vibrating beam of claim 1, wherein the sheet of dielectric material is wrapped around the pattern of electrodes and the rod to form a protective sheath.

8. The vibrating beam of claim 1, including a plurality of rods, each with a pattern of electrodes; and wherein the plurality of rods are encapsulated into a material providing a desired curved or bent shape.

9. The vibrating beam of claim 1, further including a surface or body at the distal end of the rod configured to disintegrate, coagulate, cut or treat biological tissue.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a drawing that shows two interdigitating electrode structures;

(2) FIG. 2 illustrates excess PZT rod polyimide sheet trimmed in preparation for the wrapping; process.

(3) FIG. 3 shows a PZT sheet applied to electrode sheet forming interdigitated electrodes on PZT rods;

(4) FIG. 4 depicts a solid wafer of PZT adhered to a flexible polyimide sheet, diced to 100 microns;

(5) FIG. 5 illustrates interdigitated electrodes etched to polyimide sheet;

(6) FIG. 6 shows the excess rods removed. Epoxy resin is provided between rods and a thin layer applied onto the rods;

(7) FIG. 7 shows steps associated with the construction of a basic unit;

(8) FIG. 8 is an enlarged cross section of a completed basic unit, in this case including four rods;

(9) FIG. 9A illustrates a straight case with a sharp tip configured for tissue destruction and incising;

(10) FIG. 9B shows a curved case including a tip configured for tissue destruction and incising; and

(11) FIG. 9C depicts a curved case with ball tip to disperse ultrasonic energy for therapeutic effects.

DETAILED DESCRIPTION OF THE INVENTION

(12) This invention addresses outstanding concerns regarding piezo-driven cantilevered beams applicable to surgical and other uses. A point of novelty is that the energy source is no longer required to be at the proximal end of the probe. Rather, the invention exploits the flexible nature of macro fiber composite (MFC) rods by placing them directly within the probe. The probe then is free to be of rigid or flexible material. Now the probe can be of any length as resonance is not the determining factor. The system directs movement at the end of the PZT rods that make up the MFC such that energy is transmitted directly to the operating tip. As the PZT rods are bendable, essentially any angle from longitudinal axis is possible. As there is no need for resonance the walls of the probe can be flexible and thus the probe becomes steerable.

(13) The actual rods are preferably in the range of 100 microns in diameter and of essentially any length. They are wrapped or encapsulated in a waterproof and electrically insulating dielectric material. Depending on the number of these basic units a device may or may not need heat dissipation. The guides for these basic units can be rigid (metal or a plurality of polymer materials) or flexible to create catheters and flexible devices that can be steered or floated through various channels such as vessels.

(14) In accordance with the invention, interdigitated electrodes are disposed adjacent a rod of piezoelectric material. In preferred embodiments, the electrodes are electrically conductive material such as copper, and the piezoelectric material is PZT (lead zirconate titanate). The rods may have any cross-section shape though square or rectangular is preferred to provide an elongate flat surface against which the electrodes are bonded or adhered.

(15) The Figures show the construction of a basic unit along with associated manufacturing steps. FIG. 1 shows two interdigitating units comprising finger-like electrode patterns 102, 104. The patterns may assume any operative potentials driven by generators of the types disclosed in U.S. Pat. No. 9,486,235, including one electrode being grounded while the other assumes an appropriate waveform, opposing positive-negative waveforms, and so forth. Such electrodes act as a virtual PZT wafer and a virtual stack, with each wafer elongated along the longitudinal axis of the rod, inducing a d33 mode, for example.

(16) FIG. 2 illustrates a polyimide sheet 202 trimmed in preparation for a wrapping process described in further detail below. FIG. 3 shows a PZT sheet 302 applied to the electrode sheet, forming interdigitated electrodes on PZT rods. FIG. 4 depicts a solid wafer of PZT material adhered to the flexible polyimide sheet, with the PZT sheet being diced to 100 microns. FIG. 5 illustrates the interdigitated electrodes etched to polyimide sheet, and FIG. 6 shows the excess rods removed. Epoxy resin is provided between rods and thin layer applied onto the rods.

(17) FIG. 7 shows steps associated with the construction of a basic unit, and FIG. 8 is an enlarged cross section of a completed basic unit, in this case including four rods. FIG. 9A illustrates a straight case with a sharp tip configured for tissue destruction and incising. FIG. 9B shows a curved case including a tip configured for tissue destruction and incising. FIG. 9C depicts a curved case with ball tip to disperse ultrasonic energy for therapeutic effects. The configurations of FIG. 9 are not meant to be limiting, and rather representative of potential case and tip designs, with the understanding that the case itself may be rigid or flexible depending upon the material(s) used for encapsulation.

(18) The central core of the basic unit which is essentially filled with epoxy material can carry other features, as follows:

(19) 1. Graphene fabric/fibers or mesopitch carbon fiber can carry heat. Laid into this region and heat from the action of each fiber can be carried away from the site, exiting with the electrodes

(20) 2. The fibers as described already are acting in a d33 mode for accentuating longitudinal movement as the expansion contraction of poled PZT crystals are working in the same axis as the fiber (longitudinal). If an electrode runs down within the basic unit channel and the inside of the device is lined with an electrode plate a d31 action can be created. Here the fiber will expand and contract and on contraction from the sides will lengthen (like a toothpaste tube).