EP0090265A1 - Ultrasonic transducer - Google Patents

Abstract

1. An ultrasonic applicator having an ultrasonic head which comprises a plurality of transducer elements arranged one after another or beside one another in at least one row in a predetermined configuration on a carrier component, where for the contact of the reflecting and counter-surface each transducer element carries at least one contact plate for each of these surfaces and where for the contact of the counter-surfaces along the respective transducer element arrangement at least the contact plates are consecutively arranged in the form of a comb so as to point away from the counter-surfaces at a predetermined angle, characterised in that the comb (6; 23 to 25; 43; 71 to 79; 96) consisting of contact plates (7; 49; 80) is arranged on the counter-surfaces (4; 42) of the individual transducer elements (1; 41; 70) so as to extend approximately along the centres thereof, whereas on the reflecting surfaces (3; 44) contact plates (10, 11; 28, 29; 45, 46; 87 to 93) are arranged and aligned in the form of a comb, or in the form of a common continuous baffle plate, or in a mixed form of the two, in such a manner that they extend parallel to the reflecting surfaces of the transducer elements or upwardly bent against the reflecting direction at a predetermined angle.

Description

The invention relates to an ultrasound applicator according to the preamble of patent claim 1.

An ultrasonic applicator of this type is previously known, for example, from US Pat. No. 3,952,387. Here the transducer comprises a series of rod-shaped transducer elements arranged side by side. Each transducer element consists in the usual way of a base body made of piezo material, on the radiation surface of which a first electrode layer and on the opposite surface of which a second electrode layer is applied. However, the electrode layer of the counter surface is shorter than the entire rod length. For this purpose, however, the electrode layer of the radiation surface encompasses the head end of the respective piezo rod up to the free area of the counter surface, but without coming into contact with the shorter electrode layer on the counter surface. The overlapping parts of the electrode layers in the row arrangement of the transducer elements are carriers of a first comb of contact surfaces, which serve to contact the radiation surfaces of the individual transducer elements, but which are directed in the opposite direction to the radiation direction. A second comb of contact plates, which contact the counter surfaces of the transducer elements, runs parallel to the first comb along the opposite row edges of the individual transducer elements. The contact plates are directed in the opposite direction to the radiation.

From DE-OS 30 19 410 an ultrasound applicator is also previously known, in which the transducer elements on the transducer are finely divided, with a plurality of transducer elements being electrically combined into groups by individual contact plates, each with a contact plate comb. The transducer elements again consist of piezo rods, the radiation and counter surfaces of which are now continuously provided with an electrode layer. A total of two contact plate combs are assigned to the radiation surfaces of the transducer elements, one of which is attached on the side of the counter surfaces along the left edge of the transducer element arrangement and the other on the counter surfaces along the right edge of the transducer element arrangement. The contact plates of both contact plate combs are formed in the form of triangular contact tabs made of foil material. Each contact flag is slightly curved in the opposite direction to the beam of the transducer. A common rod-shaped return conductor runs along the middle of the radiation surfaces of the transducer elements. The basic principle of the fine division of transducer elements is described in more detail in US Pat. No. 43.05 014.

The ultrasound applicators of the prior art dealt with above are specially designed for those transducers which comprise only a single row of transducer elements. A combination of several such single-row transducers to form a multiple-row transducer is hardly possible because of the special type of combing of a single row of transducer elements. The known comb contacts would interfere with each other.

The object of the present invention is to dispose of an ultrasound applicator of the type mentioned at the beginning to train that a single-row transducer can be easily expanded to a multi-row transducer.

The object is achieved by the characterizing features of claim 1.

The invention creates a single-row transducer, which is now designed with regard to the comb contact so that it can be easily expanded to a multi-row transducer. Because of the contact plate comb running centrally on the counter surfaces of the individual transducer elements, there are also optimal symmetry conditions. The load on the individual transducer elements does not have an asymmetrical effect and there are optimal forms of vibration for both the transmission and the reception case.

Further advantages and details of the invention emerge from the following description of several exemplary embodiments with reference to the drawing and in conjunction with the subclaims.

• Figur 1 einen Ultraschall-Applikator gemäß der Erfindung mit einer ersten Ausführungsform eines Einreihen-Schallkopfes,
• Figur 2 einen Ultraschall-Applikator mit einem Mehrreihen-Schallkopf, der z.B. aus Einreihen-Schallköpfen gemäß Figur 1 zusammengesetzt sein kann,
• Figur 3 einen Ultraschall-Applikator mit einer zweiten Ausführungsform für einen Einreihen-Schallkopf, der ebenfalls zu einem Mehrreihen-Schallkopf, z.B. nach Art der Figur 2, zusammengesetzt werden kann,
• Figur 4 einen Ultraschall-Applikator, der aus Mehrecksegmenten zu einem Vieleck zusammengesetzt ist, wobei jedes Mehrecksegment eine eigene Reihe hintereinander angeordneter Wandlerelemente umfaßt,
• Figur 5 die Kontaktierung der Gegenflächen der Wandlerelemente bei einem UltraschallfApplikator gemäß Figur 4,
• Figur 6 die Kontaktierung der Abstrahlflächen der Wandlerelemente bei einem Ultraschall-Applikator gemäß Figur 4,
• Figur 7 eine vergrößerte Darstellung eines äusseren Mehrecksegmentes, teilweise im Schnitt,
• Figur 8 eine erste mögliche Art der Kontaktierung eines Kontaktblechkammes,
• Figur 9 eine zweite mögliche Art der Kontaktierung eines Kontaktblechkammes,
• - Figur 10eine Modifikation des Kontaktblechkammes,
• Figur 11 eine Modifikation der Art, in der ein Trägerkörper auf der Keramik aufgebracht ist.

Show it:

• FIG. 1 shows an ultrasound applicator according to the invention with a first embodiment of a single-row transducer,
• FIG. 2 shows an ultrasound applicator with a multi-row transducer, which can be composed, for example, of single-row transducers according to FIG. 1,
• Figure 3 shows an ultrasound applicator with a second embodiment for a single-row transducer, which is also egg a multi-row transducer, for example in the manner of FIG. 2, can be assembled,
• FIG. 4 shows an ultrasound applicator which is composed of polygonal segments to form a polygon, each polygonal segment comprising its own row of transducer elements arranged one behind the other,
• 5 shows the contacting of the counter surfaces of the transducer elements in an ultrasonic applicator according to FIG. 4,
• 6 shows the contacting of the radiation surfaces of the transducer elements in an ultrasound applicator according to FIG. 4,
• FIG. 7 shows an enlarged illustration of an outer polygonal segment, partly in section,
• FIG. 8 shows a first possible way of contacting a contact plate comb,
• FIG. 9 shows a second possible way of contacting a contact plate comb,
• 10 shows a modification of the contact plate comb,
• Figure 11 shows a modification of the manner in which a carrier body is applied to the ceramic.

In FIG. 1, the single-row transducer is specially designed as a single-row array. The single-line array consists of a plurality of converter elements 1, eg 80 pieces arranged in a row one after the other. Each transducer element consists of a rod-shaped body 2 made of piezo material, in particular piezoceramic, which is metallized on the radiation surface 3 and the counter surface 4 by, for example, vapor deposition or baking, for example, Ag. The evaporated metal layers are designated 5. On the counter surfaces 4 of the individual transducer elements 1, a comb 6 of contact tabs 7, which consist, for example, of Ag, Cu or Cu alloys, is arranged approximately along their centers. The contact lugs 7 of the comb 6, which are separated from one another by slots 8 at the height of the spacing slots 9 of the transducer elements, form the hot connections for the transducer elements. The earth connections are formed by two metal foils 10 and 11 which are bent upwards in the opposite direction to the radiation of the transducer elements, for example from the same material as the contact tabs of the comb. The foils 10 and 11 are soldered along the left and right lower edge of the row of transducer elements 1 to the radiation surfaces 3 of the transducer elements. They are also slotted at the level of the converter element columns 9. However, the slots 12 do not extend to the upper edge of the film; they are only partially cut into the film.

A carrier body 13 serves as a carrier for the converter elements 1 and the comb 6 made of contact foils 7. The comb 6 made of contact tabs 7 is embedded in the carrier body 13. The carrier body 13 consists of a material that dampens ultrasonic waves well. E.g. the carrier body can be made of epoxy resin with an introduced oxidized tungsten powder. On the application side, the single-line array of FIG. 1 is completed with an adaptation body 14. This adaptation body consists e.g. made of epoxy resin.

The one-line array of FIG. 1 is preferably produced as follows: A continuous plate made of piezoceramic material, which has a metallic coating on the top and bottom and which has the outer dimensions of the one-line array to be produced, is placed on the surface that will later be the counter surface of the individual Is to form transducer elements, equipped with the comb 6 made of contact foils 7. The comb 6 consists first of all of a continuous strip of film material which, however, already has window cutouts 15 while the slots 8 have not yet been introduced. The cutouts 15 can be scraped into the film strips in such a way that the comb structure shown in FIG. 1 already results from the outset. However, the film strip may just as well be provided with self-contained windows. The comb structure shown in FIG. 1 with the cutouts 15 open at the top is obtained by cutting off the upper edge of the strip to such an extent that the window cutouts 15 are open at the top after the single-row array has been completely assembled. In addition to the film comb 6, the still unslotted continuous ceramic plate is provided with the upwardly bent contact films 10 and 11 along the edges of the later radiation surfaces of the transducer elements. The contact foils 10 and 11 are also still unslotted at this time. After assembly of the film comb 6 and the contact films 10 and 11, the carrier body 13 is applied, for example, by pouring on the carrier material. Subsequent to this production step, the transducer element is divided by sawing. For this purpose, the piezo plate with the applied carrier body 13 is sawn from the radiation surface 3 at such intervals that the dividing slots 9 result between the individual transducer elements. In order to obtain separate contact foils 7 on the comb 6 at the same time can be sawed deeper at the interfaces than the ceramic plate with the applied metallization is thick. Overall, the saw depth should be such that there are film slots 8 which clearly separate the individual contact tabs 7 of the comb 6 from one another electrically. The slots in the contact foils 10 and 11 result from the same sawing process.

FIG. 2 shows a three-line array, which is composed, for example, of three one-line arrays corresponding to FIG. 1. The three single-line arrays are labeled 20, 21 and 22. Each of the three arrays 20, 21 and 22 carries a film comb 23, 24, 25 along the centers of the counter surface of the transducer elements 1. The spacing gaps between the two outer arrays 20 and 22 from the inner array 21 are on the side of the radiation surfaces of the transducer elements 1 bridged with electrical contact strips 26 and 27. In this case, two opposite transducer elements from two adjacent arrays can always be assigned a single strip 26 or 27. However, contact strips 26 and 27 are preferably continuous strips that extend undivided along the gaps between two adjacent arrays. The contact strips can again consist of Ag, Cu or a Cu alloy, for example. Contact foils 28 and 29 again serve as external ground connections. The carrier bodies of the individual arrays are designated 30, 31 and 32. The adaptation layer 33 is common to all three arrays if all three arrays are to have the same ultrasound frequency. However, several arrays with different frequencies can also be combined with one another, with each of these arrays then having to be assigned its own adaptation layer.

FIG. 3 shows a finely divided single-line array 40. The finely divided array is basically constructed like the array of FIG. 1. It therefore again comprises transducer elements 41 arranged in a row one behind the other, which are provided with a film comb 43 along the centers of their counter surfaces 42. The outer edges of the radiation surfaces 44 of the transducer elements are again contacted with a film strip 45 and 46, respectively. The carrier body is designated 47 and the adaptation layer 48. The important difference to the array in FIG. 1 arises, however, in the fine division of the transducer elements 41. In comparison with the array in FIG. 1, for example, the width a of the finely divided transducer elements in the array in FIG. 3 is only 1/5 the width of a transducer element in the array of Figure 1. However, in order to be able to restore the original activity area, several of the finely divided transducer elements, that is to say five in the present case, are electrically combined to form a group. The group is summarized with the aid of the film comb 43, which preferably consists in the manner shown in FIG. 3 of contact tabs 49 with recesses 50 in between. The depth of cut h of the cutouts 50 is less than the total height H of the contact comb 43. It therefore remains on the area. A strip part 51 with the height B facing the surfaces of the film edge facing the transducer elements. Saw slits 52 and 53 protrude from below into this strip part 51. The saw slits 52 originate from the fine sawing of the transducer elements. They only partially extend from below into the strip part 51. In contrast, the saw slots 53 have a greater depth. They protrude over the strip part 51 into the free area of the cutouts 50 of the comb 43. The longer slots 53 divide the comb 43 again into individual, electrically separated contact tabs 49. The grid width of the contact tabs 49 along the crest 43 is R = A. It therefore always corresponds to the group width A of a group of finely divided transducer elements which are to be electrically contacted. The cutouts 50, like the cutouts of the comb of the array of FIG. 1, can have a purely rectangular shape. However, as shown in FIG. 3, it is advisable to make the cutouts 50 less wide at their open upper end than in the region of the greatest incision depth. The recess, which is wider in depth, allows large tolerance widths when sawing the ceramic. This considerably simplifies the sawing process and reduces the number of rejects.

FIG. 4 shows an ultrasound applicator, the transducer of which is composed of a total of nine polygonal segments 61 to 69 to form an octagon. The polygonal segments 61 to 68 are quadrilaterals with the trapezoidal shape shown. The central polygon segment 69 is an octagon segment. Each of the segments again comprises a multiplicity of finely divided transducer elements 70, which again come into groups by combs 71 to 79 from contact foils 80. 81 are contacted together. The components 82 are again carrier bodies made of e.g. Epoxy resin with oxidized tungsten powder. Components 83 are matching layers for the transducer.

The finely divided transducer elements 70 are again sawn from complete ceramic plates, which have the trapezoidal shape of the outer pieces 61 to 68 or the octagonal shape of the central piece 69. The Sägeplan is in the fi ^g shown for the fifth Figure 5 shows a partial. Plan view of the transducer of FIG. 4, sectioned up to the transducer elements. Accordingly, the central octagon shows the fine division of the sawing columns 84 shown. The central octagon 69 is therefore called a gan Zes sown. The outer trapezoidal quadrilaterals 61 to 68, however, are finely divided parallel to the bottom and top of the trapezoid. The saw gaps of this fine division are indicated at 85. They run concentrically around the central octagon 69 for all trapezoidal parts. The division into groups 81 in these trapezoidal pieces takes place in group advanced 86 according to a Fresnel pattern. The group width thus decreases with increasing distance from the central octagon 69. The decrease takes place in the sense that all groups 81 are phase homogeneous. This results in a uniform ultrasound radiation over the entire application area of the transducer.

FIG. 5 also shows the plan for the group contacting of the converter elements 70 along the centers of the counter surfaces of the respective converter elements. Accordingly, the trapezoidal pieces 61 to 68 are each contacted by the contact combs 72 to 78. The central octagon 69 is contacted with a continuous contact foil strip 79. This continuous contact strip 79 lies in a line with the contact combs 74 'and 78 of the trapezoidal pieces 64 and 68. This is because the direction of the fine division of the central octagon coincides with the directions of the fine division of the trapezoidal pieces 64 and 68.

The contact combs 71 to 79 are again the hot contacts for the converter elements. The earth contacts are formed in a simple manner by metal strips 87 to 93. These metal strips, which can be of the same material as the foil strips of the contact combs 71 to 79, run in the same direction on the radiation surfaces of the transducer elements as the contact combs on the counter surfaces. This is illustrated in FIG. 6, which is an application-side view of the ultrasound head 4 partly in section. The film strip 90 is continuous. Of course, it can also be separated. but must then have a contact bridge at the joints between the central octagon 69 and the adjacent trapezoid corners 64 and 68.

FIG. 7 shows a perspective view and on an enlarged scale of a trapezoid quadrilateral released from the association of the transducer of FIG. 4. In the present case it is e.g. around the trapezoidal square 61 with the comb 71 made of contact foils 80. All other trapezoidal quadrilaterals are constructed in the same way.

In FIG. 8 it is again indicated in an enlarged manner how the foil comb can be soldered or also welded onto the ceramic body by means of soldering edge 94. However, soldering or welding without an edge is also possible, as is indicated in FIG. 9 by soldering or welding seams 95. When the foil comb is soldered or welded on by means of soldering edge 94, the cutouts in the foil comb can be cut into the soldering edge up to the soldering edge. This possibility is indicated in FIG. 10 with a foil comb 96, the recesses 97 of which extend as far as the soldering edge 94.

Finally, FIG. 11 shows a modification in that a damping body 98 can also be applied to the row of transducer elements in such a way that it also encompasses their edges. With this arrangement, the unwanted edge radiation of ultrasonic energy is prevented.

The exemplary embodiment described is only of an exemplary nature. Of course there is any number of modifications that fall within the scope of the technical skills of a person skilled in the art and are therefore all within the scope of the invention.

Claims (20)

1. Ultrasound applicator with an ultrasound head, which comprises a plurality of transducer elements, which are arranged on a carrier part in a predefinable configuration at least in a row one behind the other or next to one another, with at least one contact plate for each of these surfaces for contacting the radiation and counter surface of each transducer element carries and wherein at least the contact plates for contacting the counter surfaces along the respective transducer element arrangement in the form of a comb, facing away from the counter surfaces at a predeterminable angle, are arranged one behind the other, characterized in that the comb (6; 23 to 25; 43; 71 to 79; 96) made of contact plates (7; 49; 80) is arranged on the counter surfaces (4; 42) of the individual transducer elements (1; 41; 70) running approximately along their centers, while contact plates (10, 44) 11; 28, 29; 45, 46; 87 to 93) also in the form of a comb or in the form of a common continuous baffle o which are arranged and aligned in a mixed form of the two in such a way that they run parallel to the radiation surfaces of the transducer elements or counter to the radiation direction at a predeterminable angle. 2. Ultrasonic applicator according to claim 1, characterized in that in the formation of the ultrasound head as a multi-row transducer (Figure 2 or Figure 4) with a plurality of transducer element rows each individual transducer element row on the counter surfaces of the individual transducer elements with a comb (23 to 25 ; 71 to 79) is provided from contact plates. 3. Ultrasonic applicator according to claim 2, characterized in that the. Multi-row transducer is composed of a plurality of single-row transducers (20 to 22; 61 to 69), which can have the same or different operating frequencies and each of which along its transducer element row on the counter faces of the individual transducer elements the comb (23 to 25; 71 to 79) made of contact plates, and in which the radiation surfaces of the transducer elements of transducer element rows of adjacent single-row transducers are provided with an electrical contact bridge (26, 27) at the joints or each single-row transducer has its own continuous contact means (87 to 93) for the radiation surfaces of its transducer elements is provided. 4. Ultrasonic applicator according to claim 2 or 3, characterized in that the single-row transducer is a single-row array and the multi-row transducer is a multi-row array. 5. Ultrasonic applicator according to claim 4, characterized in that in a multi-line array (Figure 2), in which a plurality of rows of transducer elements are arranged parallel to each other, the combs (23 to 25) of contact plates on the counter surfaces in a corresponding parallel formation along approximately Run in the middle of the converter elements. 6. Ultrasonic applicator according to claim 4, since - characterized in that a single-line array (Figures 1 and 3) with only a single row of transducer elements or a multi-line array with multiple rows of transducer elements or such a multi-line array (Figure 2), that consists of several individual arrays with, for example, only one individual converter element row is constructed, carries contact plates (10, 11; 45, 46; 28, 29) along each of the two outer longitudinal edges on the radiation surfaces of the transducer elements according to the characterizing part of claim 1. 7. Ultrasonic applicator according to one of claims 1 to 3, characterized in that in the case of transducers (Figure 4) in which the transducer elements (70) on the support part (82) are stacked one behind the other within polygonal segments (61 to 69) and several of these polygonal segments form a polygonal transducer in composition, each polygonal segment (61 to 69) is assigned its own comb (71 to 79) of contact surfaces (80), which is arranged on the counter surfaces of the individual transducer elements of the polygonal segment, running approximately along their centers. 8. Ultrasonic applicator according to claim 7, characterized in that the polygonal transducer from the combination of a central polygon (69), e.g. central octagon, is formed with a plurality of flush-fitting trapezoidal quadrilaterals (61 to 68). 9. Ultrasonic applicator according to claim 8, characterized in that in the central polygon (69) the transducer elements parallel to a polygonal edge and in the trapezoidal quadrilaterals (1 to 68) parallel to the upper and lower edges of the respective trapezoid, preferably finely divided, are. 10. Ultrasonic applicator according to claim 9, characterized in that on the trapezoidal quadrilaterals (61 to 68) the contact combs (71 to 78) transverse to the transducer elements along their centers in the trapezoidal symmetry line perpendicular to the upper and lower edges of the trapezoid . 11. Ultrasonic applicator according to claim 9, characterized in 'that a contact comb (79) as a continuous contact strip on the central polygon (69) extends transversely to the transducer elements on their counter surfaces along the transducer element centers. 12. Ultrasonic applicator according to one of claims 8 to 11, characterized in that a continuous contact strip for contacting the radiation surfaces is provided on the radiation surfaces of the transducer elements of the central polygon (69) or the flush-fitting trapezoidal quadrilaterals (61 to 68). 13. Ultrasonic applicator according to one of claims 1 to 12, characterized in that the comb (6; 23 to 25; 43; 71 to 79) of contact plates for the mating surfaces of the transducer elements is directed essentially perpendicular to the mating surfaces. 14. Ultrasonic applicator according to one of claims 1 to 13, characterized in that a carrier body (98) for the transducer elements extends over the end edges of the transducer elements (Figure 11). 15. Ultrasonic applicator according to one of claims 1 to 14, characterized in that the comb is folded on the counter surfaces of the transducer elements (Figure 8) or soldered directly on the face (Figure 9). 16. Ultrasonic applicator according to claim 15, characterized in that when the comb (96) is folded, the recesses (97) between the contact plates can extend to the edge of the comb (94). 17. Ultrasonic applicator according to one of claims 1 to 16 with fine division of the transducer elements on the transducer, always a plurality of transducer elements being electrically combined into groups, characterized in that the comb consists of contact plates on the counter surfaces of the transducer elements from an elongated strip of contact material, which is provided transversely to its length for specifying the comb shape with a plurality of successive recesses which are open on the strip edge facing away from the counter surfaces of the transducer elements and whose depth of incision in the strips towards the counter surfaces of the transducer elements is less than the total height of the strip and that Strip in the area of each recess is provided with at least one slot which extends through the strip back from the recess to an intermediate space between two adjacent transducer elements and that the mean distance between two successive slots in each case Etching in the strip, which are at the same time in recesses of the strip and spaces between two adjacent transducer elements, is selected so that the strip part lying between two adjacent slots in each case electrically summarizes the number of finely divided transducer elements located under the slots into a group (FIGS. 3 and 4 ). 18. Ultrasonic applicator according to claim 17, characterized in that each strip part between two continuous slots each at the level of the separating gaps between the individual finely divided transducer elements can also be provided with incision slots, but from the strip edge with which the strip on the counter surfaces of the Transducer elements is attached, only slightly, under no circumstances to the level of the incision depth of the comb recesses. 19. Ultrasonic applicator according to claim 17 or 18, characterized in that the recesses in the strip have a rectangular shape. 20. Ultrasonic applicator according to claim 17 or 18, characterized in that the recesses have a smaller width at their open upper end than in their area of greatest incision depth.

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