Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS5650696 Description 1, title of the invention Acoustic wave focusing transducer using polymer piezoelectric material DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved acoustic focusing transducer using a polymeric piezoelectric material. For example, PVDF (polyvinylidene fluoride) is a conventional inorganic piezoelectric material such as PZT (lead zirconate titanate), BaTiOa + or polymer piezoelectric material whose practical use is in progress under pressure. An electronic transducer that performs linear scan or sector scan even in an ultrasonic transducer using a piezoelectric polymer such as PVF (polyvinyl fluoride), pvc (polyvinyl chloride), pc (polycarbonate) or N-11 In the case of the scan method, for example, a concentric annular or strip divided piezoelectric body and / or a drive that scans and drives predetermined electrodes of a transducer formed by using the electrodes as main parts by a predetermined phase. there were. Further, the principle of the above-mentioned conventional method and the configuration thereof will be described with reference to FIGS. 1 and 2. That is, according to the conventional method, as seen in the longitudinal sectional view shown in FIG. 1 and the XX view in FIG. 1 shown in FIG. An electrode layer 2.4 is provided on the surface, and one of the electrodes (the back electrode 2 in the figure) and the piezoelectric body 6 are partitioned by the insulator 5 and arranged in a predetermined relationship. Each portion of the laminate partitioned by the insulator 5 is supported by the back support 1. A1. , A 2 ° BO + B 1 + B 2 indicate the sections divided concentrically by the insulator 5. In this conventional example, each concentric ring drawn by the divided piezoelectric member has its radius different from each other by λ / 2 centering on the focal point 0 when the wavelength of the ultrasonic wave at the used frequency is λ in principle and ideally 9AI + A2 + Bo, B1 of each piezoelectric body, which is determined as a part encircled by a circle drawn on the transducer surface by a sphere, 03-05-2019 1 and thus divided into a predetermined relationship. The sound wave generated by selecting the drive of B2 in a predetermined relationship is used in a state of focusing on focal point 0. That is, when every other concentric ring shown in the first order brother, for example, ring A and ring A2 are simultaneously driven, the sound wave from ring A1 and the sound wave from PJA 2 are at focal point 0 because they are r2rO-λ. Each wavelength is in focus by rl-rQ-λ / 2 when simultaneously driving adjacent concentric rings, eg, qA1 and ring B1. At 0 you will be weak. Even in the drive of the adjacent concentric rings A1 + Bl, the phases of the sound waves reaching the focal point 0 are in phase when driven so that the phases of the respective drive voltages are in antiphase so that they are mutually constructive. . Furthermore, at this time, the width of each other is set to A1. A2. Bo、B1. If a stripshaped piezoelectric body having a ratio such as B2 is used, the sound wave is sharp at one point O, passing through 0 in the figure, parallel to the transducer surface, that is, perpendicular to the drawing paper in FIG. Can be focused on a straight line. The conventional scanning transducer is formed by selectively driving the piezoelectric body divided into the predetermined relationship based on the above configuration and principle with the electrodes subdivided in the same manner as the piezoelectric body. In the conventional scanning transducer, it has been an essential requirement to divide and arrange the piezoelectric body and / or the electrode to be used. However, when an inorganic substance such as PZT (lead zirconate titanate) is used as the piezoelectric substance, first, the PZT powder is sintered to a desired shape, then it is provided with piezoelectricity by poling, and is then polished to obtain a support It is necessary to have a means to divide it into an annular shape to bond it and further to eliminate the adverse effect due to large size and loss talk between inorganic piezoelectric materials, but this brings about the precision of machining and the difficulty of micromachining Not only that, there is a high possibility of causing defects such as two cracks, and the yield is bad. Moreover, it was not easy to make the thickness of each divided piezoelectric body uniform or to make the characteristics uniform. As a solution to this point, the present inventors have already separately proposed a split type transducer using a polymeric piezoelectric film. However, the following non-negligible manufacturing improvements still remain in the transducer using the above-mentioned polymer membrane. That is, in order to drive the polymer piezoelectric material with a phase difference, it was necessary to divide at least the electrodes. In this case, there are large restrictions on wiring between many and fine electrodes, and lead extraction, so that the number of man-hours is large, and since these electrodes are difficult to process, the transducer is The production cost was expensive. SUMMARY OF THE INVENTION The object of the present invention is to solve at once the above-mentioned drawbacks of the electrode-splitting type in the above-mentioned conventional scanning transducer, and for this reason the present invention relates to a back electrode, a polymer piezoelectric material and In the transducer in which the surface electrodes are laminated, the polymeric piezoelectric material has a concavo-convex shape, and the difference between adjacent convex portions and concave portions is substantially 1 / 2λ (where λ is a used frequency) The present invention provides an acoustic wave focusing 03-05-2019 2 transducer made of a polymer piezoelectric material, characterized by satisfying the conditions equal to the wavelength of the ultrasonic wave in Embodiments of the present invention will now be described with reference to the drawings. FIG. 3 is a longitudinal sectional view of an embodiment of the acoustic focusing transducer according to the present invention, in which the concentric annular portions 2a, 2b, 2c and 2d are formed on the upper surface of the support 1 so as to be uneven. A back electrode / reflector 2 of a proper shape is laminated, and further, the polymer piezoelectric film 3 and the surface electrode 4 are in close contact with the irregularities of the back electrode / reflector EndPage: 2 To make the difference between the convex and concave parts of the back electrode / reflecting plate which forms the base of the above, that is, the difference between the symbols T and 8 in the figure, substantially be half the acoustic wavelength λ at the operating frequency. Set In this way, the difference in the distance to the focal point O of the adjacent rings is λ / 2 + λ / 2 × 2λ, and as a result, the wavelength shifts. Therefore, in the present invention having the above configuration, even if the electrodes are driven in phase, the focal point O strengthens the sound wave, which is another configuration of the conventional scanning transducer, that is, @ Finally, the same effect can be obtained as driving in the opposite phase through adjacent electrodes which are separated from each other and have complicated connections, and in the present invention, the electrodes are It has an extremely advantageous advantage in terms of construction that it can be a series without dividing. In addition, as the support body 1, polymers with small acoustic impedances, such as PMMA (polymethyl methacrylate), PUT (polyethylene te f7) left-late, nylon, an epoxy resin, etc., are used. The back electrode / reflecting plate type may use thin film metal such as Cu, A7 or the like, and the electrode and the reflecting plate may be separately formed. The scooped surface electrode 4 is a polymeric piezoelectric body 6, for example, the aforementioned PVDF or PVF. pvc and N-11, etc. (7) on H / l / A, A, e. It forms by methods, such as vapor deposition, such as Cu and Ay-, application ¦ coating of Ay- paste (conductive paste). FIG. 4 shows a longitudinal sectional view of another embodiment of the present invention, and the reference numerals 1.2 and 3.4 in the drawing are the same as those in FIG. Here, a support 1. Back electrode and reflector 2. It comprises a polymeric piezoelectric body 6 ° and a surface electrode 4. Here, instead of providing the back reflector 2 with rectangular asperities, the asperities of the back reflector are designed so that the phases of the sound waves from the respective concentric rings at the focal point O are more completely matched. The shape is determined, as shown in the figure, as a part of a concentric sphere whose radius is different by half of the wavelength λ of the used frequency around the focal point O. The range in which the same concentric sphere is used is separated in the same way as the concentric ring in the case of FIG. For example, in the case of a sphere of radius ro, the sphere of radius r,) is from the position at which the transducer surface S is cut to the position at which the sphere of radius r6 + λ / 2 is to cut the transducer surface S. In an ultrasonic transducer having 03-05-2019 3 such a configuration, the phase of the sound wave at the focal point is completely in phase, and the focusing of the acoustic wave energy at the focal point is much improved as compared with the case of the rectangular asperity. Ru. However, producing a perfect sphere on the back electrode / reflector with sufficient accuracy involves processing difficulties, so in practice it may be approximated by saw-toothed irregularities instead of spheres. Good. This shape can be manufactured without difficulty by existing technology such as ruling. Even with such an approximation, the focusability of the sound wave to the focal point 0 is much higher than when the rectangular asperity is used, and the longitudinal cross-sectional view in FIG. As shown in the figure, by giving a rounded shape and a rounded shape (cJ nori, the change of the surface becomes gentler than in the case of the concave and convex portions of a rectangle, so adhesion of the polymer piezoelectric film becomes easy and the adhesion strength becomes Benefits can also be obtained. Next, the present invention will be further described with reference to a specific example. EXAMPLE FIG. 6 is a longitudinal sectional view of an embodiment of the type shown in FIG. 3 of an acoustic focusing transducer according to the present invention. After bonding a Cu plate, which will be described in detail later, as a back electrode and reflector 2 to the PMMA support 1 (acoustic impedance Z key, 2 × 10 6 My / ln 2 · S) in the figure, using an epoxy resin, poling is performed thereon. The 90 [mu] m thick uniaxially stretched PVDF piezoelectric film treated (120 [deg.] C., 1 hour in an electric field of ID 6 V / cm) was adhered with a cyanoacrylate adhesive. The surface electrode 4 was taken. Furthermore, PET with a thickness of 15 μm was adhered to the entire surface of the AA vapor-deposited electrode, to form a surface protection EndPage: 3 film 6. The Cu plate used for the back electrode / reflecting plate 2 of the present embodiment is formed by etching a Cu plate having a diameter of 17 μm and a thickness of 300 μm and having an unevenness of 150 μm. Central circle B. The radius of the (convex part) is 3.9 vfL, and it is a Cu plate consisting of five concentric rings including this. When the transducer having such a configuration was simultaneously driven on the entire surface at a frequency of 5 MHz, it was confirmed that the sound wave was emitted in a state of being focused on one point on the front face of the transducer (the sound medium was a stroke). Moreover, according to the present embodiment, since the back electrode 2 is not a divided type as in the prior art but an integral electrode, the driving method of the conventional transducer, that is, the divided and arranged annular electrodes is electrically When driving, every other concentric ring is driven simultaneously at one time, or different from the case where adjacent concentric rings are driven in reverse phase with each other, the electrodes are divided as described above, and There is no need to connect the rings, and there is no need to arrange adjacent rings in reverse phase. According to the present invention, it is only necessary to apply a four-axis ginseng voltage between the front and back electrodes. For this reason, compared with the conventional scanning transducer, its production is easier, and the variation of the performance characteristics of each item is less, so it goes without saying that the transducer of uniform quality can be made inexpensive. It became possible to offer. Supplementally, providing such a concavoconvex on the 03-05-2019 4 reflector is easily realized using conventional techniques such as etching and ruling, and when bonding a piezoelectric body on an electrode having such a concavo-convex structure, polymer piezoelectric Since the body is rich in flexibility and flexibility with conventional inorganic piezoelectric bodies such as PZT, it is easy to bond along the irregularities of the electrode, and a film with uniform thickness and piezoelectricity It is also easy to do. 4. Brief description of the drawings. FIG. 1 is a longitudinal sectional view of a conventional scanning ultrasonic transducer, FIG. 2 is a view as seen in the direction of arrows XX in FIG. 1, FIG. Explanatory drawing of the code ¦ symbol in 0 which shows the longitudinal cross-sectional view of each another embodiment of the sound wave focusing type ¦ mold transducer using the polymeric piezoelectric film by this invention 1: Support body 2: Back electrode 6: Surface protection film patent application Person East Ltd. EndPage: 4 Procedure Amendment 54.12.14 ° Showa Date Secretary General of Patent Office (Investigator's Office Code A) 1, Display of Case Showa Patent Application No. 116654 No. 2, Invention Name 2, Name of invention Sound wave focusing type transducer 6 using polymer piezoelectric material, Related patent applicant for correction case 2, the title of the invention 03-05-2019 5
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