Patent Application
20120302888
The present invention relates to the technical field of ultrasound endoscopy. In particular, it relates to a radial array ultrasound endoscopic probe, a manufacture method thereof and a fixing and rotating device.
This application claims benefit of Chinese patent application No. 201110132195.1, filed May 23, 2011, the disclosure of which is incorporated in its entirety by reference for all purposes.
In the technical field of ultrasound endoscopy, a radial scanning probe is widely used for image diagnosis for gallbladder, pancreas and alimentary canals. At early stage of its usage in 1980s, only 90-degree ultrasound imaging could be realized by means of ultrasound endoscopy. Later on, with the technical developments, 180-degree, and even 360-degree ultrasound imaging are realized.
The earliest 360-degree image is obtained through scanning by a single-element probe, which is mechanically driven by a motor to rotate inside the endoscope. Later on, ultrasonic images can be obtained by a radial array probe through 360-degree electronic scanning, in which a motor is dispensed with. Furthermore, imaging can be quickly conducted and thus-obtained images are clearer, which renders the radial array probe applicable in examining fine structures of inner organs and tissues. A radial array ultrasound endoscopic probe mainly includes a plurality of strip elements that are arranged parallel with the axial direction of the cylinder. The more the number of the elements is, the higher the resolution of resulting images.
At present, the technique for producing radial array ultrasound probes of small scale to be placed on the top end of the endoscopy is quite complex, therefore the probes of this type are seldom commercially available. Only a few manufacturers are capable of producing the probes of this type, thus price thereof is relatively high. In the prior manufacture method for probes, it is common to prepare planar elements first and then to curl them to a circular shape. The main disadvantage associated with this method lies in the fact that curling will probably lead to an imperfect cylindrical shape and at least one interface will certainly exist. Thus there may be aberrance in the resultant images. In addition, since layers in the element (such as the acoustic matching layer, the piezoelectric ceramic or single crystal, and the backing layer) are connected before curling, break-down and disengagement of different layers may occur due to stress arising from curling.
The technical problems to be solved by the invention is to propose a simple and reliable radial array ultrasound endoscopic probe, a manufacture method thereof and a fixing and rotating device which can overcome the drawbacks of the prior art that aberrance would occur due to breaking-off caused by that the radial array ultrasound endoscopic probe is made by manufacturing the plane array first and then curling the same.
In the first aspect of the invention, it is provided a radial array ultrasound endoscopic probe, comprising a metal cylinder located at the center; a plurality of piezoelectric elements which are cut from piezoelectric ceramic or single crystal rings and are arranged around the metal cylinder, said piezoelectric elements and said metal cylinder being provided with a backing material layer for absorbing sound therebetween, said piezoelectric elements being covered with a matching material layer on the outer side thereof, and said piezoelectric elements are filled with decoupling material therebetween; a plurality of coaxial cables correspondingly connected with the plurality of piezoelectric elements, the grounding wire of each coaxial cable being connected to the metal cylinder; and a circular lattice in a gear shape which sleeves over said metal cylinder and functions to arrange and separate the coaxial cables.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, the plurality of piezoelectric elements are cut from a piezoelectric ceramic ring or a piezoelectric single crystal ring.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, the plurality of piezoelectric elements are arranged concentrically and equidistantly.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, each of the plurality of piezoelectric elements has a width not greater than 40% of its height.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, the plurality of piezoelectric elements are provided on a first cylindrical segment of the metal cylinder, the circular lattice is provided on a second cylindrical segment of the metal cylinder which is adjacent to the plurality of piezoelectric elements, and the metal cylinder at least has a exposed third cylindrical segment which is adjacent to the second cylindrical segment.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, the gears of the circular lattice has a same number as the number of the piezoelectric elements, and are arranged equidistantly and concentrically; each of the plurality of coaxial cables is correspondingly placed and fixed in one gear.
In the radial array ultrasound endoscopic probe according to the first aspect of the invention, the inner region of the ceramic or single crystal ring that exceeds the backing material layer is coated with conductive adhesive, such that the inner electrode of the piezoelectric ring is electrically connected with the metal cylinder; and the conductive adhesive is coated with insulating adhesive; the cores and the grounding wires of the coaxial cables are separated to the right and left sides of the circular lattice; the cores of all coaxial cables are connected to the marginal region of the outer electrode of the piezoelectric ring through conductive adhesive; the grounding wires of all coaxial cables are connected to the metal cylinder at the center through conductive adhesive.
In the second aspect of the invention, it is provided a manufacture method for a radial array ultrasound endoscopic probe, which comprises:
S1: the inner and outer surfaces of the piezoelectric ceramic single crystal ring are respectively plated with electrode and polarized;
S2: a backing material is filled to a metal cylinder, such that its diameter is equal to the inner diameter of the piezoelectric ring, and the length of the backing material is less than that of the piezoelectric ring;
S3: the metal cylinder coated with the backing material is adhered to the inner of the piezoelectric ring through insulating adhesive;
S4: the outer electrode of the ring is coated with solvable adhesive at the marginal region thereof for leading;
S5: the outer electrode of the ring is filled with a matching material layer, such that the thickness of the matching material layer amounts to a design value;
S6: the inner electrode of the ring is electrically connected with the metal cylinder at the center through conductive adhesive, and the surface of the conductive adhesive is coated with insulating adhesive for protection;
S7: the solvable adhesive is stripped off to expose the marginal region of the outer electrode of the piezoelectric ring;
S8: the circular plastic ring is cut so as to obtain a circular lattice in a gear shape, wherein the number of teeth of the lattice is equal to the number of the piezoelectric elements of the ultrasonic endoscopic probe, and the diameter of the circular plastic ring is slightly larger than the outer diameter of the piezoelectric ceramic or single crystal ring;
S9: the circular lattice is passed through the metal cylinder so as to abut with the exposed electrode of the piezoelectric ring, and is fixed to the metal cylinder;
S10: the coaxial cables of the same number as the piezoelectric elements of the ultrasound endoscopic probe is deployed within the concave grooves of the circular lattice, the core and the grounding wire of each coaxial cable are stripped off to expose the metal wire part, and are separated to the each side of the circular lattice;
S11: the cores of the coaxial cables are connected to the marginal region of the outer electrode of the piezoelectric ring through conductive adhesive, the grounding wires of the coaxial cables are connected to the metal cylinder through conductive adhesive, and the surface of the conductive adhesive is coated with insulating adhesive for protection;
S12: a plurality of piezoelectric elements arranged in a circle are cut out from the piezoelectric ceramic or single crystal ring which is covered with a matching material layer, wherein the cutting depth is such that the piezoelectric ring is cut through, and the cutting grooves are filled with decoupling material to solidify therein.
In the manufacture method for a radial array ultrasound endoscopic probe according to the second aspect of the invention, in Step S8, the gears of the circular plastic rings that are cut out are arranged concentrically, and equidistantly, and in Step S12, the plurality of piezoelectric elements that are cut out are arranged concentrically and equidistantly.
In the third aspect of the invention, it is provided a fixing and rotating device of the radial array ultrasound endoscopic probe as mentioned above, comprising a fixing support that protrudes out of the platform of the fixing device, and the fixing support is provided on one side thereof with a rotary head for fixing and rotating a workpiece on the other side to rotate within 360 degrees.
In the forth aspect of the invention, it is provided with a cutting method for the radial array ultrasound endoscopic probe as mentioned above, wherein the radial array ultrasound endoscopic probe is fixed by means of the fixing and rotating device according to claim 10, and is placed in a mechanical linear cutting apparatus or a laser cutting apparatus for cutting.
The radial array ultrasound endoscopic probe, the manufacture method thereof and the fixing and rotating device embodying the invention present the following advantages. Instead of cutting out all piezoelectric elements first and then arranging them in a circle as commonly used in the prior art, the plurality of piezoelectric elements according to the invention are directly cut out from the piezoelectric ceramic or single crystal ring. In this way, problems that may otherwise arise from forcedly curling multiple layers of materials of a certain thickness into a circular tube, such as non-concentricity of elements, misalignment of elements at interface, break-off of piezoelectric ceramic or single crystal, disengagement of the acoustic matching layer and the backing layer, and breaking of connection of welding points etc., are avoided. Moreover, instead of employing a flexible circuit broad for connecting signal lines as commonly used in the prior art, the circular lattice in a gear shape is utilized to deploy the signal lines of coaxial cables. In this way, all signal lines are concentrically and equidistantly aligned with the respective elements. Furthermore, spot welding is dispensed with for each element and signal line. That is, all cores are coated with conductive adhesive, connected to the piezoelectric elements, and respective signal lines are electrically disconnected in the following elements cutting process.
Hereinafter the invention will be further described with reference to the embodiments and the companying figures, wherein
a is a perspective view showing the fixing and rotating device for the radial array ultrasound endoscopic probe according to the preferable embodiment of the invention;
b is a side view showing the fixing and rotating device for the radial array ultrasound endoscopic probe according to the preferable embodiment of the invention;
The invention will be explained in detail with reference to the accompanying figures and embodiments hereinafter to further clarify the purposes, the technical solutions and advantages of the invention.
As shown in
The metal cylinder 101 is located at the center and functions as a support, and connects the electrodes of the piezoelectric elements 103 and the grounding wires of all coaxial cables 106. It is preferred, but not necessary, that the metal cylinder 101 was made of bronze due to its good machinability and conductivity.
A plurality of piezoelectric elements 103 are arranged concentrically and equidistantly around the metal cylinder 101. Various piezoelectric ceramic and piezoelectric single crystal materials may be utilized to prepare the piezoelectric elements. Furthermore, the number of the piezoelectric elements may be 32, 64, 128 or even more, but is not limited thereto in the present invention.
The backing material 102 is provided between the piezoelectric elements 103 and the metal cylinder 101. It functions to absorb ultrasound waves transmitted backwards from the piezoelectric elements 103 so as to improve the imaging resolution of the probe.
The matching material layer 104 covers around the periphery of the piezoelectric elements 103. The matching material layer 104 may consists of a single layer, two layers or a plurality of layers. The thickness and the acoustic parameters of the matching materials 104 may be designed according to the working frequency, electrical and acoustic parameters of the piezoelectric elements 103.
Each piezoelectric element 103 is connected to a very thin coaxial cable 106 so as to transmit excitation voltage signals and receive echo wave voltage signals. The diameter of coaxial cable 106 is small than or equal to the width of the piezoelectric elements 103.
The circular lattice 105 is in the shape of a gear so as to arrange the coaxial cables 106 and separate the cores and grounding wires thereof. It also conducts locating function during cutting the piezoelectric elements. As shown in
Decoupling material 107 is provided between each piezoelectric element 103 so as to decrease the crosstalk effect among the piezoelectric elements 103.
Now turn to
First, in Step 401, a ring 103 made of piezoelectric ceramic or single crystal materials is prepared. Due to the space confinement from the endoscopy specific for a certain body-cavity, the diameter and the height of the ring 103 could not be too large. The wall thickness of the ring 103 should be properly chosen according to the working frequency of the probe actual in use and the frequency of the piezoelectric materials in such a way that the higher the frequencies, the smaller the wall thickness. Generally speaking, the ring 103 is machined from bulk piezoelectric ceramic or single crystal, since the thus obtained ring may have good concentricity.
In Step 402, electrodes are prepared on the inner and outer surfaces of the piezoelectric ceramic or single crystal ring 103 through vacuum sputtering coating, chemical plating or electroplating. The ring is subject to polarization so as to have piezoelectric performance.
In Step 403, a metal cylinder 101 is further prepared, the diameter of which is slightly larger than the inner diameter of the plastic pipe as shown in
In Step 404, the backing material is uniformly coated with adhesive (such as epoxy resin) having good fluidity and high cohesion strength, and then the ring 103 is sleeved over the backing material 102. The backing material and the ring will combine together after solidification.
In Step 405, a small length (the location to be coated with conductive adhesive 1061) of electrode located peripherally on the right side of the ring 103 is coated with a narrow band of adhesive. The adhesive may be alkyd, which may solidify within atmosphere environment at room temperature and may be removed by means of solvents such as acetone. The purpose of coating a band of adhesive is to protect the coated electrode from being screened by the material of the matching layer, and to allow the peripheral electrode of the ring 103 to connect to the coaxial cable signal lines.
In Step 406, the ring 103 adhered with the backing material is positioned within a special mold, and the material of matching layer that has been properly formulated is filled therein. The matching layer and the ring adhered with the backing material are drawn out together after solidification. It should be ensured that the height of the matching material layer 104 filled therein does not exceed the band of adhesive (alkyd) that have already been coated. The acoustic impedance of the matching material layer 104 is chosen as a function of those of the specific piezoelectric ceramic or single crystal and body tissues, and its thickness depends on the working frequency of the probe. The solidified cylinder is machined to the extent that it assumes a proper diameter such that the thickness of matching material layer is equal to the calculated value. There may be designed and prepared a single layer, two layers, or even more layers of matching material, and the invention imposes no limit thereto.
In Step 407, the inner region of the ring 103 that protrudes beyond the backing material 102 is coated with conductive adhesive 108 such that the inner electrode of the ring 103 electrically connects with the metal cylinder 101 located centrally. And the adhesive 108 is coated with an adhesive 109 (such as epoxy resin, etc.) to avoid electrical connection between the inner and outer electrodes.
In Step 408, the band of adhesive (alkyd) that has been coated and solidified is removed through acetone such that the electrode coated with the adhesive is exposed.
In Step 409, a circular plastic ring is cut out on a special fixing and rotating device using a mechanical linear cutting apparatus or a laser cutting apparatus so as to obtain a circular lattice in the shape of a gear structure with the number of teeth being equal to the number of the piezoelectric elements of the ultrasound endoscopic probe.
In Step 410, the gear-shaped circular lattice 105 prepared as described in
In Step 411, the coaxial cables 106, the number of which is equal to the number of the piezoelectric elements of the probe, are located in the circular lattice 105 in order, and are fixed with adhesive.
In Step 412, the cores 1061 and grounding wires 1062 of the coaxial cables 106 are each stripped off for a small fraction of metal wires to be exposed, and are separated by the circular lattice 105 at both sides. The exposed part of the cores is such that it overlaps over the electrode portion of the ring 103 that is exposed outside; and conductive adhesive 108 is employed to adhere the exposed part of the cores with the said electrode portion of the ring 103 that is exposed outside; then an adhesive layer (such as epoxy resin, etc.) is coated thereon for protection. The grounding wires 1062 of the coaxial cables 106 are adhered to the metal cylinder 101 through conductive adhesive, and are electrically connected with the inner electrodes of the ring 103 through the metal cylinder 101. Likewise, an adhesive layer is coated on the conductive adhesive for protection.
In Step 413, the thus prepared workpiece is installed to the fixing and rotating device as shown in
Turn to
Now turn to
The radial array ultrasound endoscopic probe provided by the invention, used in conjunction with an endoscope, can electronically scan the surrounding tissues and organs panoramically within human alimentary canals so as to pick up a radial ultrasound image of the surrounding tissues and organs. The invention possesses the following advantages.
A Simple Manufacture Process
Instead of cutting out all piezoelectric elements first and then arranging them in a circle as commonly used in the prior art, the plurality of piezoelectric elements according to the invention are directly cut out from the piezoelectric ceramic or single crystal ring. In this way, problems that may otherwise arise from forcedly curling multiple layers of materials of a certain thickness (at least including an acoustic matching layer, a piezoelectric layer, and a backing layer) into a circular tube, such as non-concentricity of arrays, misalignment of arrays at interface, break-off of piezoelectric ceramic or single crystal, disengagement of the acoustic matching layer and the backing layer, and breaking of connection of welding points etc., are avoided.
Instead of employing a flexible circuit broad for connecting signal lines as commonly used in the prior art, the circular lattice in a gear shape is utilized to deploy the signal lines of coaxial cables. In this way, all signal lines are concentrically and equidistantly aligned with the elements equal-distantly. Furthermore, spot welding is dispensed with for each element and signal line. That is, all cores are coated with conductive adhesive, connected to the piezoelectric elements, and electrically disconnected in the following array cutting process.
A Reliable Manufacture Process
The desired thickness is achieved through machining after filling the special mold with the backing material and the matching material. Thus it is ensured that each layer of material has a uniform thickness, can be firmly engaged with each other, and the surface of the probe is a perfect smooth cylinder.
A structure of a circular plastic pipe capable of naturally tightening is employed to connect the uncut radial array probe without adhesive or connecting mechanism (such as threads) with the rotary head. In this way the uncut probe and the rotary head may rotate in a concentric state so as to ensure the precision of rotary cutting.
The special fixing and rotating device is used with a cutting apparatus, such that the piezoelectric ring, the matching layer and the backing layer fixed on the piezoelectric ring can be controlled to rotate precisely. Equally distanced elements with equal width may result from cutting.
The invention is described with reference to the specific embodiments. Nevertheless, the skilled in the art will appreciate that there may exit various changes and equivalent substitutions without departing the scope of the invention. In addition, various modifications can be made to the invention for adapting to specific application fields or materials, without departing from the protection scope of the invention. Therefore, the invention is not limited to specific embodiments as disclosed herein, and to the contrary, the invention includes all embodiments falling within the protection scope as defined by the claims
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110132195.1 | May 2011 | CN | national |
