JP4304112B2 - Manufacturing method of ultrasonic probe - Google Patents

Description

  The present invention relates to a method for manufacturing an ultrasonic probe, and more particularly to a method for easily manufacturing a two-dimensional type ultrasonic probe with improved ultrasonic transmission / reception characteristics.

  Conventionally, many ultrasonic probes have been devised that generate a periodic distortion by applying a voltage of a predetermined frequency to a piezoelectric material and obtain an ultrasonic wave having a frequency corresponding to the distortion. The structure of a general ultrasonic probe is to form a surface that absorbs ultrasonic waves on one side of a piezoelectric material that actually generates distortion and generates ultrasonic waves and does not transmit / receive ultrasonic waves. A backing layer that serves to broaden the frequency band so that a short pulse signal can be transmitted and received is placed, and on the other side, it plays a role of filling the gap of acoustic impedance to the subject etc. when using an ultrasonic probe The acoustic matching layer is arranged, and a plurality of members are laminated as a whole.

  In the structure of a normal ultrasonic probe, a ground electrode is disposed on the upper surface of a piezoelectric material and a signal electrode is disposed on the back surface, and a ground line and a signal line are connected to each other. In general, the signal line penetrates the backing layer and is led behind the piezoelectric material. The ground wire is once drawn out to the side surface of the piezoelectric material and then led to the rear side of the piezoelectric material. In this case, for example, it is pulled out by a sheet-like ground line. Further, a configuration in which the signal line is also drawn out from the side of the piezoelectric material has been devised (for example, see Patent Document 1 and Patent Document 2).

Japanese Patent Laid-Open No. 5-23341 Japanese Patent Application Laid-Open No. 7-312799

  By the way, in recent years, development of a two-dimensional type ultrasonic transducer in which vibration elements are arranged in a matrix has been actively performed. When a plurality of vibration elements are arranged, the wiring of signal lines and ground lines becomes complicated, and it is necessary to consider crosstalk suppression between signal lines. Further, when the vibration elements are arranged in a matrix, if the mutual separation is not sufficiently performed, it causes acoustic crosstalk and directivity degradation.

  Therefore, there is a demand for a method of forming a two-dimensional type ultrasonic transducer that can be easily wired for each signal line and ground line and that can suppress the occurrence of crosstalk and the deterioration of directivity.

  The present invention has been made in view of the above problems, and provides an ultrasonic probe manufacturing method capable of improving directivity and suppressing crosstalk between signal lines and improving manufacturing efficiency. For the purpose.

  In order to achieve the above object, the present invention includes a step of forming a strip-shaped piezoelectric material having electrodes on opposite surfaces, and a fluid acoustic matching layer forming material is poured on one side of the piezoelectric material. In addition, a fluidized backing layer forming material is poured into the other side and cured to form a plate-shaped composite, and the electrodes exposed on the front and back surfaces of the plate-shaped composite are separated into a plurality at a predetermined pitch. Connecting a possible leader line, and extending the piezoelectric material along the backing layer on which the open end side of the leader line is formed in a direction away from the piezoelectric material, and forming the wiring complex and the plate A step of forming a block body by alternately laminating a spacer in the plate thickness direction of the wiring complex, a direction of removing the upper portion of the spacer from the acoustic matching layer side of the block body, and a strip-shaped piezoelectric material Duplicate The matrix of grooves formed in the direction of separation, the characterized in that it comprises the steps of a strip-like piezoelectric material is separated into individual devices corresponding to each lead wire, the.

  According to this configuration, the electrodes (signal electrode and ground electrode) formed on the opposing surface of the piezoelectric material are drawn out from the side surfaces of the piezoelectric material and the backing layer, respectively. Each wiring complex is completely separated in the arrangement direction by the spacer. Furthermore, the elements are completely separated by forming grooves in a matrix form from the acoustic matching layer side of the block body. By manufacturing in such a step, each element is completely separated, and deterioration of directivity and generation of acoustic crosstalk can be suppressed. Also, use a foreign material such as an adhesive to connect the piezoelectric material to the acoustic matching layer and the backing material by pouring the fluid backing forming material and the fluid acoustic matching layer forming material into the piezoelectric material and curing it. Therefore, it is possible to obtain an ideal connection configuration as a probe, and it is possible to easily manufacture an ultrasonic probe that can efficiently transmit and receive ultrasonic waves.

  In order to achieve the above object, according to the present invention, in the above configuration, the piezoelectric material includes electrodes on an acoustic matching layer forming surface and a backing layer forming surface, respectively, and the step of forming the wiring complex includes The lead wire is connected to the end face of each electrode exposed on the opposing surface orthogonal to the acoustic matching layer forming surface and the backing layer forming surface.

  According to this configuration, an ultrasonic probe that transmits and receives ultrasonic waves using the longitudinal vibration of the piezoelectric material can be easily manufactured.

  In order to achieve the above object, according to the present invention, in the above configuration, in the step of forming the electrode, the end surface of the electrode on the backing layer forming surface side is offset inward from the end surface of the piezoelectric material, and the acoustic matching layer is formed. The lead wire connected to the electrode on the side is not contacted.

  According to this configuration, it is easy to bring the electrodes arranged on the front and back surfaces of the piezoelectric material and the lead lines drawn from each of them into a non-contact state, and the lead lines can be easily wired.

  In order to achieve the above object, according to the present invention, in the above configuration, the piezoelectric material has electrodes on opposing surfaces orthogonal to an acoustic matching layer forming surface and a backing layer forming surface, and the wiring composite The step of forming is characterized in that a lead wire is connected to each electrode.

  According to this configuration, it is possible to easily manufacture an ultrasonic probe that transmits and receives ultrasonic waves using the lateral vibration accompanying the lateral vibration of the piezoelectric material. In this case, the signal line and the ground line are arranged in a direction orthogonal to the ultrasonic radiation surface. That is, the ground wire is not interposed between the piezoelectric material and the acoustic matching layer. As a result, the coupling between the piezoelectric material and the acoustic matching layer can be performed satisfactorily, and the degradation of the ultrasonic radiation performance can be suppressed. In addition, since no ground wire is interposed, the bonding force between the piezoelectric material and the acoustic matching layer can be easily and sufficiently secured.

  In order to achieve the above object, according to the present invention, in the above-described configuration, the step of forming the composite includes forming a backing layer thinner than a piezoelectric material and forming the block body. The thin portion of the backing layer is supplemented with the thick portion of the spacer.

  According to this configuration, it is possible to uniformly increase the distance between the wiring complexes arranged via the spacers during manufacturing, and easily manufacture an ultrasonic probe that suppresses the occurrence of crosstalk. Can do.

  In order to achieve the above object, according to the present invention, in the above-described configuration, the step of forming the composite includes: backing the composite according to the stacking order of the wiring composite and the spacer in the block forming step. It is characterized by changing the length of the layer.

  According to this configuration, it is possible to obtain a structure in which the lead lines drawn from the elements divided in a matrix form and the external terminals can be easily connected.

  In order to achieve the above object, according to the present invention, in the above configuration, the cured acoustic matching layer forming member adjusts acoustic characteristics by cutting a separation direction with respect to the piezoelectric material with a predetermined thickness. It is characterized by.

  According to this configuration, it is possible to accurately and easily form an acoustic matching layer having a size corresponding to the characteristics of the ultrasonic probe.

  In order to achieve the above object, according to the present invention, in the above configuration, the step of forming the composite includes forming the composite with a thickness that is 1/2 of the thickness required for the wiring composite, The step of forming the wiring complex is such that the signal lines are in contact with two wiring complexes in which the signal line is arranged on one side of the 1 / 2-thickness complex and the ground line is arranged on the other side. A laminated wiring complex is formed in which the signal lines are sandwiched between a pair of ground lines.

  According to this configuration, when the thickness of the piezoelectric material sandwiched between the signal line and the ground line is halved, the impedance of the piezoelectric material is ½ of the piezoelectric material having a normal thickness. When two piezoelectric materials sandwiched between the signal line and the ground wire are stacked to have a normal thickness, the impedance is ¼ of the normal thickness of the piezoelectric material. As a result, a low impedance ultrasonic probe can be formed without changing the size of the outer diameter.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram of the structure of the ultrasonic probe 10 of the present embodiment. The ultrasonic probe 10 of the present embodiment includes a piezoelectric material 12 (vibration element) that generates ultrasonic waves, a backing layer 14, and an acoustic matching layer 16. The backing layer 14 absorbs ultrasonic waves and allows the probe to transmit and receive a short pulse signal, thereby fulfilling the role of expanding the frequency band. The acoustic matching layer 16 plays a role of filling a gap of acoustic impedance with respect to the subject or the like. FIG. 1 shows an example in which a two-dimensional type ultrasonic probe 10 is configured by arranging a plurality of independently controllable piezoelectric materials 12 in a matrix.

  In this embodiment, as shown in FIG. 2, a signal electrode 18 a is formed on the lower surface of the piezoelectric material 12, and its end surface is in contact with the signal line 18 disposed on the side surface of the piezoelectric material 12. Further, the end surface of the ground electrode 20 a formed on the upper surface of the piezoelectric material 12 is in contact with the ground wire 20 disposed on the opposite side surface of the piezoelectric material 12 with respect to the signal line 18. Then, by applying a voltage between the signal line 18 and the ground line 20, ultrasonic waves are radiated in the stacking direction of the acoustic matching layer 16. At this time, the end surface of the signal electrode 18 a formed on the lower surface of the piezoelectric material 12 on the ground line 20 side is offset inward from the end surface of the piezoelectric material 12. That is, the signal line 18 and the ground line 20 can be fixed to both side surfaces of the piezoelectric material 12 so as not to contact the ground electrode 20a connected to the ground line 20 on the acoustic matching layer side. In FIG. 2, the backing layer 14 is not shown.

  As described above, when a predetermined voltage is applied between the signal line 18 and the ground line 20, the piezoelectric material 12 vibrates in the Z direction in the figure. In the configuration of FIG. 2, desired ultrasonic waves are radiated from the ultrasonic probe 10 using the vibration in the Z direction, that is, ultrasonic waves generated by a so-called longitudinal effect method.

  As is apparent from FIGS. 1 and 2, in the present embodiment, the signal line 18 and the ground line 20 penetrate the backing layer 14 from the side surface of each piezoelectric material 12, and the back surface of the ultrasonic probe 10. It extends to the side. That is, the signal line 18 and the ground line 20 can be connected to each vibrating element constituting the ultrasonic probe, and accurate control of the vibrating element, that is, accurate ultrasonic wave transmission / reception control can be performed. It becomes possible. In addition, since it is possible to make each vibration element substantially independent, it is possible to suppress deterioration of directivity of ultrasonic waves. Furthermore, since each vibration element becomes a substantially independent state, it can contribute to suppression of mutual crosstalk. In particular, as shown in FIG. 1, since the ground line 20 passes straight through the backing layer 14 and the ground line 20 is interposed between the signal lines 18, crosstalk between the signal lines 18 is suppressed. It becomes possible to reduce signal degradation.

  Hereinafter, the manufacturing method of the two-dimensional type ultrasonic probe 10 of the present embodiment will be described with reference to FIGS.

  As a first step, as shown in FIG. 3 (a), for example, on the front and back surfaces of the plate-like piezoelectric material 22 made of piezoelectric ceramics such as barium titanate, PZT, lead titanate, etc. The signal electrode 18a and the ground electrode 20a are formed by a suitable material by any means such as vapor deposition, sputtering, and printing.

  Subsequently, as shown in FIG. 3B, grooves 24 having a predetermined pitch are formed on one electrode formation surface (for example, the formation surface of the signal electrode 18a) by means such as etching. The groove 24 is for preventing the ground line 20 from coming into contact with the signal electrode 18a when the ground line 20 (when the groove 24 is provided on the formation surface of the signal electrode 18a) is connected as described above. is there. Next, as shown in FIG. 3C, the piezoelectric material 22 is cut into strips along the grooves 24. The width of the strip is the width of the vibration element. As described above, the groove 24 has a signal electrode on the inner side of the end face of the piezoelectric material 22a after being cut into a strip shape so that the signal electrode 18a does not come into contact when the ground wire 20 is connected to the piezoelectric material 22a. This is for offsetting 18a. Therefore, the etching width in FIG. 3B is a width obtained by adding a cutting margin to the width of the offset groove 24a in FIG. It is desirable that the etching depth be appropriately selected to a depth that does not cause electrical connection or influence between the ground line 20 and the signal line 18 (piezoelectric material forming step).

  Next, as shown in FIG. 3D, the cut piezoelectric material 22a is disposed at a predetermined position of the mold 23. In this case, as shown in FIG. 3E, the piezoelectric material 22a is disposed in the mold 23 so that the offset groove 24a is on the upper surface. At this time, since the holding portion 26 for holding the piezoelectric material 22a is formed in the mold 23, the positioning of the piezoelectric material 22a can be performed easily and accurately. The mold 23 is formed with a recess 28 that is divided into regions 28a and 28b by the piezoelectric material 22a. The piezoelectric material 22a is arranged so that the offset groove 24a faces the region 28a side.

  Then, the regions 28a and 28b of the recess 28 are completely covered with a mold lid (not shown). At this time, as shown in FIG. 4A, the mold lid covering the region 28a is molded so that the thickness of the backing layer forming material 30 is smaller than the thickness of the piezoelectric material 22a (for example, half the thickness). The lid has a convex shape that can be fitted into the region 28 a of the concave portion 28. Next, the fluid backing layer forming material 30 is injected from the injection gate 28c to fill the region 28a, and the excess backing layer forming material 30 is discharged from the discharge gate 28d. In addition, it is preferable that the backing layer forming material 30 is shaped so as to be gradually thin with an inclination so that the ground line 20 can be fixed without being bent to the backing layer 14 to be formed. In this state, the backing layer forming material 30 is cured.

  Simultaneously with or before or after the formation of the backing layer 14, the fluidic acoustic matching layer forming material 32 is injected into the region 28b from the injection gate 28c to fill the region 28b. Similar to the backing layer forming material 30, the excess acoustic matching layer forming material 32 is discharged from the discharge gate 28d. Note that the acoustic matching layer forming material 32 and the backing layer forming material 30 are selected from those having a property of adhering to the piezoelectric material 22a on which electrodes are formed by curing.

  In FIG. 4B, the backing layer forming material 30 and the acoustic matching layer forming material 32 after being subjected to a predetermined curing process are taken out from the mold 23 together with the piezoelectric material 22a, and the injection gate and the discharge gate portions are cut off. A plate-like composite 34 in a state is shown (complex forming step). In this state, the height h0 and the thickness t0 of the acoustic matching layer 16 are accurately obtained. FIG. 4C shows a cross-sectional view of the composite 34. As apparent from FIG. 4C, the acoustic matching layer forming material 32 (acoustic matching layer 16), the ground electrode 20a, the piezoelectric material 22a, the signal electrode 18a, and the backing layer forming material 30 (backing layer 14) are laminated. It is in a state. At this time, since the fluid acoustic matching layer forming material 32 and the backing layer forming material 30 are brought into contact with the piezoelectric material 22a on which each electrode is formed and cured, the acoustic matching layer can be used without using any adhesive or the like. 16 and the backing layer 14 can be connected (adhered) to the piezoelectric material 22a, and the boundary state between the piezoelectric material 22a and the piezoelectric material 22a is ideal without causing noise such as attenuation of ultrasonic waves and unnecessary reflection. Can be realized.

  Subsequently, as illustrated in FIG. 4D, the ground line 20 that contacts the end portion of the ground electrode 20 a is formed on one side of the composite 34 (for example, the side where the backing layer 14 is thinned). As shown in FIG. 4E, the signal line 18 that contacts the end of the signal electrode 18a is formed on the other surface side of the composite 34. The ground line 20 and the signal line 18 can be easily formed by, for example, vapor deposition or sputtering (wiring complex forming step). Note that, when the ground line 20 and the signal line 18 are formed by vapor deposition, sputtering, or the like, the shape can be arbitrarily and easily selected. Therefore, in the present embodiment, FIG. 4 (d) and FIG. 4 (e). As shown in FIG. 4, a shape that is continuous at the contact portion of the ground electrode 20a and the signal electrode 18a and is separated into a comb shape at the lower portion is employed. In this case, when the piezoelectric material 22a is separated later, it is not necessary to separately separate the ground line 20 and the signal line 18, and efficient production can be performed. Needless to say, planar ground lines and signal lines may be formed, and the ground lines 20 and the signal lines 18 may be separately separated by etching or the like.

  A cross-sectional view of a wiring complex 36 in which the ground wire 20 and the signal line 18 are formed on the complex 34 is shown in FIG. As is apparent from FIG. 4F, the signal electrode 18a and the ground line 20 are not in electrical contact due to the presence of the offset groove 24a described above.

  As shown in FIG. 4G, a predetermined number of the wiring composites 36 formed in this way are alternately arranged via spacers 38 to form block bodies 40 (block body forming step). The spacer 38 used here is preferably formed of the same material as the backing layer 14 or an equivalent material. For example, the spacer 38 is formed in advance using a mold or the like. As is clear from FIG. 4G, the shape of the spacer 38 has a thick portion corresponding to the thin portion of the backing layer 14 of the wiring composite 36, and the wiring composite 36 and the spacer 38 It has a rectangular shape. In this way, by forming a thin portion in the backing layer 14 and forming a thick portion in the spacer 38, the distance between the wiring complexes 36 that are alternately arranged via the spacer 38 can be increased. Thus, electrical crosstalk between the signal lines 18 can be suppressed. Of course, even if the thickness of the backing layer 14 and the spacer 38 is uniform, the signal line 18 is separated, so that sufficient electrical crosstalk is suppressed.

  The wiring composite 36 and the spacer 38 can be joined with, for example, an epoxy adhesive. Note that the size of the ultrasonic probe 10 to be finally obtained can be determined by the width of the wiring complex 36 in the vertical direction, and the size in the horizontal direction can be determined by wiring when the block body 40 is formed. It can be arbitrarily determined by the number of sequences of the complex 36 and the spacer 38.

  Subsequently, in order to separate the piezoelectric material 22a in the block body 40 for each predetermined vibration element, first, as shown in FIG. 5A, the side surface of the acoustic matching layer 16 of the block body 40 is connected to the wiring complex 36 and the spacer. 38 in the arrangement direction (the direction of cut 1) with a predetermined pitch (the desired width of the vibration element, the position where the signal line 18 (ground line 20) is at the center of each vibration element, and a predetermined depth (slightly on the backing layer 14). Dicing is performed at a depth of (cutting depth) into a groove 42 as shown in FIG. 5B, and the piezoelectric material 22a forming the wiring composite 36 is separated into individual piezoelectric materials 12 (vibrating elements). The dicing depth at this time is such that a separation groove is formed on the backing layer 14 beyond the piezoelectric material 22a from the acoustic matching layer 16 side, that is, at least the acoustic matching layer 16 and the piezoelectric material 12 are connected to the signal line 18. Every complete The depth to be separated.

  Further, as shown in FIG. 5 (b), dicing with a predetermined depth is performed in the direction of cut 2 perpendicular to the direction of cut 1 to form a groove 44 as shown in FIG. Also, the acoustic matching layer 16 is separated into a matrix, and the acoustic matching layer 16 is completely separated for each piezoelectric material 12. In this case, the groove 44 is formed so as to exclude the upper portion of the spacer 38, and the depth is preferably the same as that of the groove 42 (element isolation step).

  Finally, the grooves 42 and 44 formed for separating the acoustic matching layer 16 and the piezoelectric material 12 include, for example, a bubble body made of urethane curable resin or resin in order to suppress acoustic crosstalk. A silicon adhesive or the like is injected for sealing. This stop can reduce crosstalk. In addition, the acoustic matching layer 16 and the piezoelectric material 12 that are acoustically and physically divided can be stably held.

  When the groove 42 is formed by the cut 1, the cutting load acts on the piezoelectric material 22a in order to cut the piezoelectric material 22a. The spacer 38 has a function of absorbing the cutting load at this time, and can prevent the piezoelectric material 22a from being damaged. Of course, the cutting load on the piezoelectric material 22a can be reduced by considering the dicing speed and the like. In this case, the height of the spacer 38 used in FIG. 4G can be lowered in advance by the depth of the groove 44, and the dicing of the cut 2 can be omitted.

  By manufacturing the ultrasonic probe according to the above procedure, as shown in FIG. 5C, the piezoelectric material 12 is substantially arranged in a matrix, and the signal line 18, for each piezoelectric material 12, It is possible to easily form a two-dimensional type ultrasonic probe 10 in which a pair of ground wires 20 are connected and the crosstalk is suppressed acoustically and electrically with good directivity. Further, since the signal line 18 and the ground line 20 separated for each piezoelectric material 12 can be easily extended to the back side of the backing layer 14, an individual electric circuit is provided for each piezoelectric material 12. Since they can be connected and controlled differently for each piezoelectric material 12, it is possible to easily manufacture the ultrasonic probe 10 that contributes to improving the degree of freedom in circuit design.

  Further, in the mold 23 shown in FIG. 4A and the like, a flow path to which the injection gate 28c and the discharge gate 28d for the acoustic matching layer forming material 32 are connected is provided obliquely with respect to the acoustic matching layer 16 formation region. However, this is for forming the holding portion 26 and forming the burr due to the presence of the injection gate 28c and the discharge gate 28d in a portion where the height h0 and the thickness t0 of the acoustic matching layer 16 are not affected. . Therefore, the shape of the mold 23 can be appropriately selected as long as the shape can be obtained accurately without holding the piezoelectric material 22a and the height h0 and the thickness t0 of the acoustic matching layer 16 without additional processing such as dicing. .

  In addition, since the thickness T of the backing layer 14 generally does not require high accuracy, in the examples of FIGS. 3D and 4B, the size is appropriately adjusted by dicing or the like along with the removal of burrs. However, similarly to the region 28b for the acoustic matching layer, the injection gate 28c for the backing layer may be disposed on the same side as the discharge gate 28d, and the thickness T of the backing layer 14 may be defined by the mold 23. .

  FIG. 6 shows a structural example of a vibration element that uses vibration characteristics different from the structure described in FIG. That is, the signal electrode and the ground electrode are formed on the opposing surface of the piezoelectric material 12 orthogonal to the laminated surface of the acoustic matching layer 16, and the signal line 18 and the ground line 20 are connected to each signal electrode and the ground electrode. Yes. At this time, when a predetermined voltage is applied between the signal line 18 and the ground line 20, the piezoelectric material 12 vibrates in the X direction in FIG. The vibration in the Z direction is generated by a so-called X-direction lateral effect method, and an ultrasonic wave is generated by the vibration in the Z direction to emit a desired ultrasonic wave from the radiation surface of the ultrasonic probe.

  Also in the ultrasonic probe described with reference to FIG. 6, the backing layer 14 connected to the lower surface side of the piezoelectric material 12 is omitted, but the signal line 18 and the ground line 20 are backed from the side surface of the piezoelectric material 12. It penetrates the layer 14 (see FIG. 1) and extends to the back side of the ultrasonic probe 10. Therefore, the signal line 18 and the ground line 20 are not interposed between the bonding between the acoustic matching layer 16 and the piezoelectric material 12 and between the bonding between the piezoelectric material 12 and the backing layer 14. That is, the acoustic matching layer 16, the piezoelectric material 12, and the backing layer 14 can be directly joined. As a result, the acoustic matching layer 16 and the backing layer 14 can be firmly bonded to the piezoelectric material 12. In addition, since the signal line 18 and the ground line 20 do not exist in the ultrasonic radiation direction, the piezoelectric material 12 and the acoustic matching layer 16 can be coupled well, and the ultrasonic radiation performance is improved. Can be maintained.

  Further, as apparent from FIG. 6, the acoustic matching layer 16 laminated on the piezoelectric material 12 can be completely separated for each piezoelectric material 12 without being affected by the signal line 18 and the ground line 20. Even when arranged in a matrix as shown in FIG. 1, ultrasonic waves radiated from adjacent piezoelectric materials 12 can radiate ultrasonic waves from each piezoelectric material 12 in a desired direction without interfering with each other. it can. As a result, the directional characteristics as the ultrasonic probe 10 can be improved. Further, since the signal line 18 and the ground line 20 separated for each piezoelectric material 12 can be easily extended to the back surface side of the backing layer 14, the processing for each piezoelectric material 12 is facilitated. Since the control for each piezoelectric material 12 becomes easy, the degree of freedom in circuit design of the electric circuit connected to the piezoelectric material 12 is improved.

  Also in the configuration of FIG. 6, as shown in FIG. 1, the ground line 20 can extend straight through the backing layer 14 and extend to the back surface side. That is, since the ground line 20 can be easily interposed between the signal lines 18, crosstalk between the signal lines 18 can be suppressed, and signal deterioration can be reduced. .

  FIG. 7 shows a schematic procedure of a manufacturing method of the lateral effect utilization type ultrasonic probe shown in FIG.

  As a first step, as shown in FIG. 7 (a), for example, on the front and back surfaces of the plate-like piezoelectric material 22 made of piezoelectric ceramics such as barium titanate, PZT, lead titanate, etc. The signal electrode 18a and the ground electrode 20a are formed by a suitable material by any means such as vapor deposition, sputtering, and printing (electrode formation step).

  Next, as shown in FIG. 7B, the plate-shaped piezoelectric material 22 is cut into strip-shaped piezoelectric material 22a having a desired size. The width of the strip is the width of the vibration element. When the lateral effect is used, each electrode is disposed on both side surfaces of the piezoelectric material 22a, so that the contact between the signal electrode and the ground line does not occur. Therefore, it is not necessary to form the groove 24 as shown in FIG. In this state, as shown in FIG. 7C, a strip-shaped piezoelectric material 22a having a signal electrode 18a and a ground electrode 20a on the opposing surface is formed.

  Subsequently, the acoustic matching layer forming material 32 is poured into one side of the piezoelectric material 22a by the same procedure as that described with reference to FIGS. 3 (f), 4 (a), and 4 (b). The backing layer forming material 30 is poured onto the other side to form the backing layer 14. At this time, as described above, the thickness of the backing layer 14 is made thinner (for example, half the thickness) than the thickness of the piezoelectric material 22a. Further, it is preferable that the backing layer 14 is inclined so that the ground wire 20 can be fixed without bending. FIG. 7D shows a side view of the piezoelectric material 22 a having the acoustic matching layer 16 and the backing layer 14, that is, the composite 46. Subsequently, as shown in FIG. 7E, the ground line 20 is formed on one surface side of the composite 46 (for example, the side where the backing layer 14 is thinned) so as to contact the ground electrode 20a. Further, the signal line 18 in contact with the signal electrode 18 a is formed on the other surface side of the composite body 46. The ground line 20 and the signal line 18 can be easily formed by, for example, vapor deposition or sputtering. A cross-sectional view of a wiring complex 48 in which the ground wire 20 and the signal line 18 are formed on the complex 46 is shown in FIG. As is apparent from FIG. 7E, the signal electrode 18a and the ground line 20 are not in contact at all, and therefore the offset groove 24a as shown in FIG. 3C is not necessary. Even in the structure using the lateral effect, electrical crosstalk can be further suppressed by forming a thin portion in the backing layer 14 and forming a thick portion in the spacer 38. Of course, the backing layer 14 and the spacer 38 may each have a uniform thickness.

  As described above, in the case of the lateral effect type ultrasonic transducer, the signal electrode and the ground electrode are not interposed between the bonding of the acoustic matching layer 16 and the piezoelectric material 12 and between the bonding of the piezoelectric material 12 and the backing layer 14. That is, the acoustic matching layer 16, the piezoelectric material 12, and the backing layer 14 can be directly joined, and can be firmly joined to the piezoelectric material 22 a when the acoustic matching layer 16 and the backing layer 14 are cured.

  The wiring complex 48 formed as described above is arranged via a spacer 38 as shown in FIG. 4G to form a block body. Subsequently, dicing in a matrix form according to the procedure of FIGS. 5 (a) to 5 (c), and a matrix type ultrasonic probe composed of ultrasonic vibration elements that can be individually controlled by the signal line 18 and the ground line 20. Create

  FIG. 7F shows another example of forming the ground line. In FIG. 4D, by dividing the ground electrode 20a into a comb shape, the vibration element is completely independent and the acoustic crosstalk is suppressed. However, the acoustic crosstalk is suppressed by another method. If it can be performed satisfactorily, the ground line may be shared as shown in FIG. When the common ground line 20 is used, the block body 52 is separated by the common ground line 20 for each wiring complex 48. As a result, when the ultrasonic probe is operated, the signal lines 18 in the arrangement direction of the wiring complex 48 are reliably separated from each other, and it is possible to suppress mutual electrical crosstalk. Therefore, signal degradation during operation can be reduced. On the other hand, when the common ground line 20 formed in each wiring complex 48 is simply drawn out to the back surface side of the backing layer 14, the number of ground lines 20 of the wiring complex 48 is extended. The effect of sharing 20 is somewhat impaired. Therefore, as shown in FIG. 7 (f), a tab 50 is formed on a part of the common ground line 20 formed in each wiring complex 48 and extends to the side of the wiring complex 48. After the block body 52 is formed, when the tabs 50 exposed on the side surfaces of the block body 52 are collectively connected with a band 54 (for example, a gold material), the interference does not interfere with the signal line 18 extending to the back side of the backing layer 14. All the ground lines 20 can be drawn out and connected as a common line, and the effect of sharing the ground line 20 can be sufficiently obtained.

  In the case of FIG. 7F, when the formation of the wiring composite 48 is completed, grooves 56 reaching the backing layer 14 are formed at a predetermined pitch corresponding to each signal line by dicing or the like on the wiring composite 48. The ultrasonic transducers are separated into a matrix when the block body 52 is formed by separating the individual elements and making the height of the spacer 38 coincide with the depth of the groove 56. An acoustic probe can be completed.

  By the way, in the above-described ultrasonic probe manufacturing method (the one using the vertical effect and the one using the horizontal effect), various additional effects can be obtained by changing only part of the manufacturing process. For example, the acoustic matching layer 16 connected to the upper surface side of the piezoelectric material 22a changes the acoustic characteristics of the ultrasonic wave depending on the thickness in the stacking direction. Therefore, the thickness of the acoustic matching layer 16 needs to be set accurately, and it is desirable that the thickness of the acoustic matching layer 16 can be selected and adjusted arbitrarily and easily according to the characteristics of the ultrasonic probe to be manufactured. Therefore, as shown in FIG. 8 (a), the acoustic matching layer 16 is formed in advance thickly (for example, thickness t), and is cut into a thickness t0 as necessary as shown in FIG. 8 (b). By doing so, a composite having desired acoustic characteristics can be easily formed.

  Further, for example, in the ultrasonic probe shown in FIG. 5 and the like, the wiring complex 36 and the spacer 38 are all configured to have the same length. Therefore, the connection process between the signal line and the ground line drawn to the end of the backing layer 14 is somewhat complicated. Therefore, as shown in FIG. 9A, the lengths of the wiring complex 36 and the spacer 38 are changed in the stacking order (in the case of FIG. 9A, the length is changed shorter toward the right side). At this time, the length of the spacer 38 is set to be relatively shorter than the length of the wiring complex 36, so that the signal lines and the ground lines are connected to the wiring complex 36 and the ground line when the block body 40 is formed. The spacers 38 are separated step by step in the stacking direction, and can be easily connected to external terminals. FIG. 9B shows a completed ultrasonic probe after the block body 40 is diced in the direction of cut 1 and cut 2 shown in FIG. In this configuration, the length of the backing layer is adjusted at the stage of forming the composite.

  FIG. 10 shows an application example of the above-described embodiment to the lateral effect, that is, an application example of a structure in which the signal line 18 and the ground line 20 are formed on the side surface facing the direction orthogonal to the ultrasonic radiation direction of the piezoelectric material 12. Is shown. In FIG. 10, the backing layer 14 is not shown. FIG. 10 illustrates only one vibration element 58 after being divided individually in the actual ultrasonic probe 10.

  The structure shown in FIG. 10 has a 1/2 thickness in order to obtain the required thickness t0 of the piezoelectric material 60 (for example, the same thickness as the piezoelectric material 12 (22a) described in FIG. 6, FIG. 7, etc.). Two piezoelectric materials 60 of thickness (t1) are bonded together.

  The piezoelectric material 60 forms the signal line 18 and the ground line 20 on the side surface facing the direction orthogonal to the ultrasonic radiation direction according to the procedure described in FIG. In FIG. 10, the shape after separation into individual piezoelectric materials 60 is shown. However, in the actual manufacturing process, a plate having a thickness t1 is formed by the procedure shown in FIG. The state separated by dicing in the process is shown in FIG.

  The signal line 18 and the ground line 20 connected to the piezoelectric material 60 are, for example, a sheet-like wiring material pasted or a pattern printed on a composite in which a gold material is formed with a thickness t1 that is 1/2 of a desired thickness t0. It is formed by vapor deposition or sputtering. Subsequently, the two wiring composites on which the signal line 18 and the ground line 20 are formed are face-to-face joined so that the signal lines 18 come into contact with each other as shown in FIG. The joining method at this time is arbitrary. For example, the bonding surface of the two wiring composites to be bonded is not completely flat. For example, an epoxy conductive adhesive or the like is used to bond the two to make electrical contact. obtain.

  By adopting such a structure, the impedance related to each piezoelectric material 60 sandwiched between the signal line 18 and the ground line 20 is ½ that of the thickness t0. When two piezoelectric materials sandwiched between the signal line 18 and the ground line 20 are stacked to a thickness of t0, the total impedance is obtained by sandwiching the piezoelectric material of the thickness t0 between the signal line 18 and the ground line 20. 1/4 of the thing. That is, when a wiring composite having a piezoelectric material having a thickness t0 is formed, the electrical characteristics can be improved, and a high-performance ultrasonic probe can be formed.

  The multilayer type wiring complex formed as described above is completed as an ultrasonic probe 10 by forming a block body according to the same procedure as shown in FIGS. The lead-out of the ground line 20 may be individually extended to the back side of the backing layer 14 or may be extended as a common ground line. Moreover, as shown in FIG.7 (f), you may make it extend to the side surface of the backing layer 14. As shown in FIG.

  In FIG. 10, the acoustic matching layer 16 may be formed at the same time when the backing layer is formed on the piezoelectric material 60, or may be stacked on the piezoelectric material 60 after the two piezoelectric materials 60 are stacked. Good. In the case of retrofitting, since the shape accuracy of the acoustic matching layer 16 is easily obtained, it is suitable for improving the overall accuracy of the ultrasonic probe 10. On the other hand, in the case of tipping, the manufacturing process is simplified, which is suitable for improving manufacturing efficiency. Therefore, it is preferable to appropriately select the order in which the acoustic matching layer 16 is formed.

  In the embodiment described above, the example in which the acoustic matching layer 16 and the backing layer 14 are bonded to the upper and lower surfaces of the piezoelectric material 22a using the mold 23 has been described. For example, the piezoelectric layer disposed on the surface plate is used. The acoustic matching layer forming material 32 and the backing layer forming material 30 may be arbitrarily poured on the upper and lower surfaces of the material 22a, and after curing, the acoustic matching layer 16 and the backing layer 14 may be formed by cutting or the like. Of course, this structure can be applied to an ultrasonic probe using a lateral effect, and the same effect can be obtained.

  Further, in the present embodiment, the radiation of ultrasonic waves is described. However, the ultrasonic probe 10 of the present embodiment can be used for reception of ultrasonic waves and for both transmission and reception, and the same effect. Can be obtained.

It is a structure conceptual diagram of the ultrasonic probe concerning the embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating details of a signal line and a ground line connected to a side surface of a piezoelectric material in the ultrasonic probe of FIG. 1. It is explanatory drawing explaining the first stage of the manufacturing procedure of the ultrasonic probe which concerns on embodiment of this invention. It is explanatory drawing explaining the middle stage of the manufacture procedure of the ultrasonic probe which concerns on embodiment of this invention. It is explanatory drawing explaining the last stage of the manufacturing procedure of the ultrasonic probe which concerns on embodiment of this invention. In the ultrasonic probe which concerns on embodiment of this invention, it is explanatory drawing explaining the detail of the signal wire | line connected to the side surface of the piezoelectric material using a lateral effect, and a ground line. It is explanatory drawing explaining the outline of the manufacturing procedure of the ultrasonic probe using the piezoelectric material shown in FIG. It is explanatory drawing explaining the method to adjust the thickness of the acoustic matching layer in the manufacture process of the ultrasonic probe which concerns on embodiment of this invention. It is explanatory drawing explaining the example of the drawing-out method of the signal wire | line and a ground wire in the manufacture process of the ultrasonic probe which concerns on embodiment of this invention. It is explanatory drawing explaining the example of an applied structure of the ultrasonic probe which concerns on embodiment of this invention.

Explanation of symbols

  10 ultrasonic probe, 12, 22a, 60 piezoelectric material, 14 backing layer, 16 acoustic matching layer, 18 signal line, 18a signal electrode, 20 ground line, 20a ground electrode, 22 piezoelectric material, 23 mold, 24, 42, 44, 56 groove, 24a offset groove, 26 holding portion, 28 recess, 28a, 28b region, 28c injection gate, 28d discharge gate, 30 backing layer forming material, 32 acoustic matching layer forming material, 34, 46 composite, 36, 48 Wiring complex, 38 spacer, 40, 52 block body, 50 tabs, 54 bands, 58 vibration elements.

Claims (8)

Forming a strip-shaped piezoelectric material having electrodes on the opposing surface;
Pouring a fluid acoustic matching layer forming material on one side with a piezoelectric material in between, pouring a fluid backing layer forming material on the other side, and curing each to form a plate-like composite;
Lead wires that can be separated into a plurality of predetermined pitches are connected to the electrodes exposed on the front and back surfaces of the plate-like composite, and separated from the piezoelectric material along the backing layer on which the open ends of the lead wires are formed. Extending in a direction to form a wiring complex;
A step of forming a block body by alternately laminating the wiring composite and a plate-like spacer in the thickness direction of the wiring composite; and
A matrix-like groove is formed in the direction of removing the upper portion of the spacer from the acoustic matching layer side of the block body and in the direction of separating the strip-shaped piezoelectric material into a plurality of strips, and the strip-shaped piezoelectric material corresponds to each lead line. Separating into individual elements;
A method for manufacturing an ultrasonic probe, comprising: The method of claim 1, wherein
The piezoelectric material has electrodes on an acoustic matching layer forming surface and a backing layer forming surface, respectively, and the step of forming the wiring composite is exposed on an opposing surface orthogonal to the acoustic matching layer forming surface and the backing layer forming surface, respectively. A method of manufacturing an ultrasonic probe, wherein a lead wire is connected to the end face of each electrode. The method of claim 2, wherein
The step of forming the electrode is characterized in that the end surface of the electrode on the backing layer forming surface side is offset inward from the end surface of the piezoelectric material so as not to contact the lead wire connected to the electrode on the acoustic matching layer side. Manufacturing method of ultrasonic probe. The method of claim 1, wherein
The piezoelectric material has electrodes on opposing surfaces orthogonal to the acoustic matching layer forming surface and the backing layer forming surface, and the step of forming the wiring complex includes connecting a lead wire to each electrode. Manufacturing method of ultrasonic probe. The method according to any one of claims 1 to 4, wherein
The step of forming the composite is characterized in that the thickness of the backing layer is made thinner than the thickness of the piezoelectric material, and the step of forming the block body is to supplement the thin part of the backing layer with the thick part of the spacer. Manufacturing method of ultrasonic probe. The method according to any one of claims 1 to 5, wherein
The step of forming the composite is characterized in that the length of the backing layer of the composite is changed according to the stacking order of the wiring composite and the spacer in the step of forming the block. Method. In the manufacturing method according to any one of claims 1 to 6,
The method of manufacturing an ultrasonic probe, wherein the cured acoustic matching layer forming member adjusts acoustic characteristics by cutting a separation direction with respect to the piezoelectric material with a predetermined thickness. In the manufacturing method according to any one of claims 4 to 7,
The step of forming the composite includes forming the composite with a thickness that is half the thickness required for the wiring composite,
The step of forming the wiring complex is such that the signal lines are in contact with two wiring complexes in which the signal line is arranged on one side of the 1 / 2-thickness complex and the ground line is arranged on the other side. A method of manufacturing an ultrasonic probe, comprising: stacking and forming a laminated wiring complex in which a signal line is sandwiched between a pair of ground lines.

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