JP6252248B2 - Ultrasonic device, manufacturing method thereof, probe, electronic apparatus, and ultrasonic imaging apparatus - Google Patents

Description

  The present invention relates to an ultrasonic device, a manufacturing method thereof, a probe, an electronic apparatus, an ultrasonic imaging apparatus, and the like using the same.

  As disclosed in Patent Document 1, an ultrasonic device including an ultrasonic transducer element is generally known. The ultrasonic transducer element includes a substrate having an element array including a plurality of ultrasonic transducer elements arranged in an array. The element array is covered with an acoustic matching layer. The acoustic matching layer couples an acoustic lens to the element array.

JP 2010-125068 A

  In Patent Document 1, the acoustic matching layer is divided for each ultrasonic transducer element. A separation material is filled between adjacent acoustic matching layers. The acoustic matching layer is formed of a solid material, while the separating material is formed of a rubber-based material. Therefore, although the ultrasonic vibration propagating from the ultrasonic transducer element does not pass between adjacent ultrasonic transducer elements, it is reflected at the interface between the acoustic matching layer and the separating material and propagates to the acoustic lens. The reflected ultrasonic waves are emitted from the acoustic lens with a time delay, and the accuracy of ultrasonic measurement is lowered.

  An ultrasonic device that contributes to improvement in accuracy of ultrasonic measurement has been desired.

  (1) One aspect of the present invention is a substrate having an element array including a plurality of ultrasonic transducer elements arranged in an array, an acoustic matching layer formed of a base material and a filler, and covering the element array An ultrasonic device in which the proportion of the occupied volume of the filler per unit volume is large between the adjacent ultrasonic transducer elements as compared to the range of the ultrasonic transducer elements in a plan view in the thickness direction of the substrate About.

  The ultrasonic transducer element vibrates ultrasonically when ultrasonic waves are transmitted. Ultrasonic waves travel from the ultrasonic transducer element through the acoustic matching layer and are emitted from the surface of the ultrasonic device. The acoustic matching layer matches the acoustic impedance between the ultrasonic transducer element and the object to be imaged. As a result of the acoustic impedance matching, the reflection of ultrasound at the interface of the acoustic matching layer is reduced. At this time, in the adjacent ultrasonic transducer elements, ultrasonic vibration propagates in the acoustic matching layer from one ultrasonic transducer element toward the other ultrasonic transducer element. Since the proportion of the volume occupied by the filler is large between adjacent ultrasonic transducer elements, the ultrasonic vibration is efficiently attenuated. Thus, crosstalk is prevented between adjacent ultrasonic transducer elements. Since the base material of the acoustic matching layer is continuous between adjacent ultrasonic transducer elements, reflection of ultrasonic vibration is suppressed. The irregular reflection of ultrasonic waves is suppressed. The accuracy of ultrasonic measurement is improved.

  (2) The ratio of the occupied volume of the filler may have a gradient between the range of the ultrasonic transducer elements and between the adjacent ultrasonic transducer elements. The ratio of the volume occupied by the filler gradually changes from the range of the ultrasonic transducer elements toward the range between adjacent ultrasonic transducer elements. Is effectively suppressed. In this way, irregular reflection of ultrasonic waves is reliably suppressed.

  (3) The range of the ultrasonic transducer element in the acoustic matching layer may increase as the distance from the ultrasonic transducer element increases. The ultrasonic vibration propagates in the acoustic matching layer while spreading from the ultrasonic transducer element. Therefore, if the region where the occupied volume of the filler is small increases as the distance from the ultrasonic transducer element increases, the ultrasonic vibration entering the region where the occupied volume of the filler is high is suppressed. In this way, the irregular reflection of the ultrasonic wave is further effectively suppressed.

  (4) The average particle diameter of the filler may be larger between the adjacent ultrasonic transducer elements than the range of the ultrasonic transducer elements. Thus, the average particle diameter of the filler is used for adjusting the ratio of the occupied volume. If the average particle size is large, the proportion of occupied volume increases.

  (5) The number of fillers may be greater between adjacent ultrasonic transducer elements than the range of the ultrasonic transducer elements. Thus, the number of fillers is used for adjusting the ratio of the occupied volume. If the number of fillers increases, the proportion of occupied volume increases.

  (6) The ultrasonic device may be used by being incorporated in a probe. At this time, the probe may include an ultrasonic device and a casing that supports the ultrasonic device.

  (7) The ultrasonic device may be used by being incorporated in an electronic apparatus. In this case, the electronic apparatus can include an ultrasonic device and a processing unit that is connected to the ultrasonic device and processes the output of the ultrasonic device.

  (8) The ultrasonic device may be used by being incorporated in an ultrasonic imaging apparatus. At this time, the ultrasonic imaging apparatus includes an ultrasonic device, a processing unit that is connected to the ultrasonic device, processes the output of the ultrasonic device, generates an image, and a display device that displays the image. Can be provided.

  (9) In another aspect of the present invention, the ultrasonic transducer element is adjacent to a substrate having an element array including a plurality of ultrasonic transducer elements arranged in an array in a plan view in the thickness direction of the substrate. And a step of applying a second material in a region where the ultrasonic transducer element is disposed, and the first material is compared with the second material. In addition, the present invention relates to a method for manufacturing an ultrasonic device in which the ratio of the occupied volume of filler per unit volume in the base material is large. Thus, the above-described ultrasonic device is manufactured.

  (10) In the method for manufacturing an ultrasonic device, the space between the first materials may be filled with the second material after the first material is cured. The first material applied to the substrate can be formed in a tapered shape as the distance from the surface of the substrate increases. As a result, in the region of the ultrasonic transducer element, a space is formed that widens as the distance from the ultrasonic transducer element increases. The region where the proportion of the occupied volume of the filler is small can have a shape that widens as the distance from the ultrasonic transducer element increases.

  (11) In another aspect of the present invention, a substrate having an element array including a plurality of ultrasonic transducer elements arranged in an array is larger than the first filler in the particle size range of the first value and the first value. Applying a flowable material containing a second filler having a particle size range of a second value, covering the element array with the material, and generating ultrasonic vibrations with the individual ultrasonic transducer elements; Based on the ultrasonic vibration, the second filler is moved toward the region between the ultrasonic transducer elements adjacent from the range of the ultrasonic transducer elements in a plan view from the thickness direction of the substrate, And a step of unevenly distributing the second filler in a region between the adjacent ultrasonic transducer elements. Thus, the above-described ultrasonic device is manufactured.

1 is an external view schematically showing a specific example of an electronic apparatus according to an embodiment, that is, an ultrasonic diagnostic apparatus. It is an enlarged front view of an ultrasonic probe. 1 is an enlarged plan view of an ultrasonic device according to a first embodiment. It is sectional drawing along the AA line of FIG. FIG. 5 is an enlarged partial cross-sectional view of FIG. 4 schematically showing the structure of the acoustic matching layer according to the first embodiment. It is a figure which shows the manufacturing process of an ultrasonic device, Comprising: It is an expanded partial sectional view of a board | substrate. It is a figure which shows the manufacturing process of an ultrasonic device, Comprising: It is an expanded partial sectional view of the board | substrate which shows the apply | coated 1st raw material roughly. It is a figure which shows the manufacturing process of an ultrasonic device, Comprising: It is an expanded partial sectional view of the board | substrate which shows the apply | coated 2nd raw material roughly. FIG. 5 is an enlarged partial cross-sectional view of FIG. 4 schematically showing the structure of an acoustic matching layer according to a second embodiment. It is a figure which shows the manufacturing process of an ultrasonic device, Comprising: It is an expansion partial sectional view of the board | substrate which shows the apply | coated raw material roughly. It is a figure which shows the manufacturing process of an ultrasonic device, Comprising: It is an expanded partial sectional view of the board | substrate which shows the raw material at the time of the application of an ultrasonic vibration roughly. FIG. 6 is an enlarged partial cross-sectional view schematically showing a structure of an acoustic matching layer according to a modification of the first embodiment corresponding to FIG. 5. FIG. 10 is an enlarged partial cross-sectional view schematically showing a structure of an acoustic matching layer according to a modification of the second embodiment corresponding to FIG. 9.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

(1) Overall Configuration of Ultrasonic Diagnostic Apparatus FIG. 1 schematically shows a specific example of an electronic apparatus, that is, an ultrasonic diagnostic apparatus (ultrasonic imaging apparatus) 11 according to an embodiment of the present invention. The ultrasonic diagnostic apparatus 11 includes an apparatus terminal (processing unit) 12 and an ultrasonic probe (probe) 13. The apparatus terminal 12 and the ultrasonic probe 13 are connected to each other by a cable 14. The apparatus terminal 12 and the ultrasonic probe 13 exchange electric signals through the cable 14. A display panel (display device) 15 is incorporated in the device terminal 12. The screen of the display panel 15 is exposed on the surface of the device terminal 12. In the device terminal 12, an image is generated based on the ultrasonic wave detected by the ultrasonic probe 13. The imaged detection result is displayed on the screen of the display panel 15.

  As shown in FIG. 2, the ultrasonic probe 13 has a housing 16. An ultrasonic device 17 is accommodated in the housing 16. The surface of the ultrasonic device 17 can be exposed on the surface of the housing 16. The ultrasonic device 17 outputs an ultrasonic wave from the surface and receives a reflected wave of the ultrasonic wave. In addition, the ultrasonic probe 13 can include a probe head 13b that is detachably connected to the probe main body 13a. At this time, the ultrasonic device 17 can be incorporated into the housing 16 of the probe head 13b.

  FIG. 3 schematically shows a plan view of the ultrasonic device 17. The ultrasonic device 17 includes a base 21. An element array 22 is formed on the base 21. The element array 22 includes an array of thin film ultrasonic transducer elements (hereinafter referred to as “elements”) 23 arranged in an array. The array is formed of a matrix having a plurality of rows and a plurality of columns. In addition, a staggered arrangement may be established in the array. In the staggered arrangement, the even-numbered element groups 23 need only be shifted by half the row pitch with respect to the odd-numbered element groups 23. The number of elements in one of the odd and even columns may be one less than the number of the other element.

  Each element 23 includes a vibration film 24. In FIG. 3, the outline of the diaphragm 24 is drawn with a dotted line in a plan view in a direction perpendicular to the film surface of the diaphragm 24 (a plan view from the thickness direction of the substrate). A piezoelectric element 25 is formed on the vibration film 24. The piezoelectric element 25 includes an upper electrode 26, a lower electrode 27, and a piezoelectric film 28. A piezoelectric film 28 is sandwiched between the upper electrode 26 and the lower electrode 27 for each element 23. These are stacked in the order of the lower electrode 27, the piezoelectric film 28 and the upper electrode 26. The ultrasonic device 17 is configured as a single ultrasonic transducer element chip (substrate).

  A plurality of first conductors 29 are formed on the surface of the base 21. The first conductors 29 extend parallel to each other in the row direction of the array. One first conductor 29 is assigned to each row of the elements 23. One first conductor 29 is commonly connected to the piezoelectric film 28 of the elements 23 arranged in the row direction of the array. The first conductor 29 forms the upper electrode 26 for each element 23. Both ends of the first conductor 29 are connected to a pair of lead wires 31 respectively. The lead wires 31 extend parallel to each other in the column direction of the array. Accordingly, all the first conductors 29 have the same length. Thus, the upper electrode 26 is connected in common to the elements 23 of the entire matrix. The first conductor 29 can be formed of iridium (Ir), for example. However, other conductive materials may be used for the first conductor 29.

  A plurality of second conductors 32 are formed on the surface of the base 21. The second conductors 32 extend parallel to each other in the column direction of the array. One second conductor 32 is assigned to each element 23 in one row. One second conductor 32 is disposed in common on the piezoelectric film 28 of the elements 23 arranged in the column direction of the array. The second conductor 32 forms a lower electrode 27 for each element 23. For example, a laminated film of titanium (Ti), iridium (Ir), platinum (Pt), and titanium (Ti) can be used for the second conductor 32. However, other conductive materials may be used for the second conductor 32.

  Energization of the element 23 is switched for each column. Linear scan and sector scan are realized according to such switching of energization. Since the elements 23 in one column output ultrasonic waves simultaneously, the number of columns, that is, the number of rows in the array, can be determined according to the output level of the ultrasonic waves. For example, the number of lines may be set to about 10 to 15 lines. In the figure, five lines are drawn without illustration. The number of columns in the array can be determined according to the spread of the scanning range. The number of columns may be set to 128 columns or 256 columns, for example. In the figure, there are omitted and 8 columns are drawn. The roles of the upper electrode 26 and the lower electrode 27 may be interchanged. That is, while the lower electrode is commonly connected to the elements 23 of the entire matrix, the upper electrode may be commonly connected to the elements 23 for each column of the array.

  The outline of the base body 21 has a first side 21a and a second side 21b that are partitioned by a pair of parallel lines and face each other. One line of the first terminal array 33 a is arranged between the first side 21 a and the outline of the element array 22. One line of the second terminal array 33 b is arranged between the second side 21 b and the outline of the element array 22. The first terminal array 33a can form one line parallel to the first side 21a. The second terminal array 33b can form one line parallel to the second side 21b. The first terminal array 33 a includes a pair of upper electrode terminals 34 and a plurality of lower electrode terminals 35. Similarly, the second terminal array 33 b includes a pair of upper electrode terminals 36 and a plurality of lower electrode terminals 37. Upper electrode terminals 34 and 36 are connected to both ends of one lead-out wiring 31, respectively. The lead wiring 31 and the upper electrode terminals 34 and 36 may be formed symmetrically on a vertical plane that bisects the element array 22. Lower electrode terminals 35 and 37 are connected to both ends of one second conductor 32, respectively. The second conductor 32 and the lower electrode terminals 35 and 37 may be formed symmetrically on a vertical plane that bisects the element array 22. Here, the outline of the base 21 is formed in a rectangular shape. The outline of the base 21 may be square or trapezoidal.

  A first flexible printed wiring board (hereinafter referred to as “first wiring board”) 38 is connected to the base body 21. The first wiring board 38 covers the first terminal array 33a. Conductive lines, that is, first signal lines 39 are formed at one end of the first wiring board 38 individually corresponding to the upper electrode terminal 34 and the lower electrode terminal 35. The first signal lines 39 are individually faced and joined to the upper electrode terminal 34 and the lower electrode terminal 35, respectively. Similarly, the base 21 is covered with a second flexible printed wiring board (hereinafter referred to as “second wiring board”) 41. The second wiring board 41 covers the second terminal array 33b. Conductive lines, that is, second signal lines 42 are formed at one end of the second wiring board 41 so as to individually correspond to the upper electrode terminal 36 and the lower electrode terminal 37. The second signal line 42 is individually faced and joined to the upper electrode terminal 36 and the lower electrode terminal 37.

  As shown in FIG. 4, the base 21 includes a substrate 44 and a coating film 45. A coating film 45 is formed on the entire surface of the substrate 44. An opening 46 is formed in the substrate 44 for each element 23. The openings 46 are arranged in an array with respect to the substrate 44. The contour of the region where the opening 46 is disposed corresponds to the contour of the element array 22. A partition wall 47 is defined between two adjacent openings 46. Adjacent openings 46 are partitioned by a partition wall 47. The wall thickness of the partition wall 47 corresponds to the interval between the openings 46. The partition wall 47 defines two wall surfaces in a plane extending parallel to each other. The wall thickness corresponds to the distance between the two wall surfaces. That is, the wall thickness can be defined by the length of a perpendicular line sandwiched between the wall surfaces perpendicular to the wall surfaces. The substrate 44 may be formed of a silicon substrate, for example.

The covering film 45 includes a silicon oxide (SiO ₂ ) layer 48 stacked on the surface of the substrate 44 and a zirconium oxide (ZrO ₂ ) layer 49 stacked on the surface of the silicon oxide layer 48. The coating film 45 is in contact with the opening 46. Thus, a part of the coating film 45 forms the vibration film 24 corresponding to the outline of the opening 46. The vibrating membrane 24 is a portion of the coating film 45 that can vibrate in the thickness direction of the substrate 44 because it faces the opening 46. The film thickness of the silicon oxide layer 48 can be determined based on the resonance frequency.

  A lower electrode 27, a piezoelectric film 28, and an upper electrode 26 are sequentially stacked on the surface of the vibration film 24. The piezoelectric film 28 can be formed of, for example, lead zirconate titanate (PZT). Other piezoelectric materials may be used for the piezoelectric film 28. Here, the piezoelectric film 28 completely covers the second conductor 32 under the first conductor 29. A short circuit between the first conductor 29 and the second conductor 32 can be avoided by the action of the piezoelectric film 28.

  An acoustic matching layer 51 is laminated on the surface of the base 21. The acoustic matching layer 51 covers the element array 22. The film thickness of the acoustic matching layer 51 is determined according to the resonance frequency of the vibration film 24. For example, a silicone resin film can be used for the acoustic matching layer 51. The acoustic matching layer 51 fits in the space between the first terminal array 33a and the second terminal array 33b. The edge of the acoustic matching layer 51 is separated from the first side 21 a and the second side 21 b of the base 21. The acoustic matching layer 51 has a smaller contour than the contour of the base 21.

  An acoustic lens 52 is disposed on the acoustic matching layer 51. The contour of the acoustic lens 52 overlaps the contour of the acoustic matching layer 51. Therefore, the edge of the acoustic lens 52 is separated from the first side 21 a and the second side 21 b of the base 21. The acoustic lens 52 is in close contact with the surface of the acoustic matching layer 51. The acoustic lens 52 is bonded to the base body 21 by the action of the acoustic matching layer 51. The outer surface of the acoustic lens 52 is formed as a partial cylindrical surface. The partial cylindrical surface has a bus parallel to the first conductor 29. The curvature of the partial cylindrical surface is determined according to the focal position of the ultrasonic wave transmitted from one row of elements 23 connected to one second conductor 33. The acoustic lens 52 is made of, for example, a silicone resin. The acoustic lens 52 has an acoustic impedance close to that of a living body.

  A protective film 53 is fixed to the base 21. The protective film 53 is formed from a material having water shielding properties such as an epoxy resin. However, the protective film 53 may be formed of other resin materials. The protective film 53 is in contact with the acoustic lens 52 and the acoustic matching layer 51. Here, the protective film 53 is fixed to the acoustic lens 52 and the side surfaces 52 a and 51 a of the acoustic matching layer 51. The side surfaces 52 a and 51 a rise from the surface of the substrate 21 perpendicular to the surface of the substrate 21. In FIG. 4, the protective film 53 sandwiches the acoustic lens 52 and the acoustic matching layer 51 at the contact surfaces 53 a that extend in parallel with the generatrix of the acoustic lens 52 and intersect the substrate 21 at right angles along the two virtual planes 54 a and 54 b. . At this time, the side surfaces 52a and 51a of the acoustic lens 52 and the acoustic matching layer 51 are flush with each other. The protective film 53 covers the second conductor 32 and the lead wiring 31 on the surface of the base 21 between the acoustic matching layer 51 and the first and second wiring boards 38 and 41. Similarly, the protective film 53 covers the ends of the first wiring board 38 and the second wiring board 41 on the base 21.

  A backing material 56 is fixed to the back surface of the base 21. The back surface of the substrate 21 is overlaid on the surface of the backing material 56. The backing material 56 closes the opening 46 on the back surface of the ultrasonic device 17. The backing material 56 can comprise a rigid substrate. Here, the partition wall 47 is coupled to the backing material 56. The backing material 56 is joined to each partition wall 47 at at least one joining region. An adhesive can be used for bonding.

(2) Acoustic matching layer according to the first embodiment As shown in FIG. 5, the acoustic matching layer 51 according to the first embodiment includes a base material 57 and a filler 58. The filler 58 is dispersed in the base material 57. Base material 57 is formed of a silicone resin. For the filler 58, for example, at least one selected from the group of zinc oxide powder, zirconium oxide powder, alumina powder, silica powder, titanium oxide powder, silicon carbide powder, aluminum nitride powder, carbon powder, and boron nitride powder is used. The base material 57 includes a first region 57 a that extends in the range of the vibration film 24 of the element 23 and a second region 57 b that extends between the adjacent elements 23. The second area 57b connects the first areas 57a. In the first zone 57a, the filler 58 has a first average particle size. In the second zone 57b, the filler 58 has a second value average particle size larger than the first value. Here, the number of fillers 58 per unit volume is approximately equal. As a result, the ratio of the occupied volume of the filler 58 per unit volume is larger in the region between the adjacent elements 23 than in the range of the elements 23 in plan view in the thickness direction of the base 21. Here, the first region 57 a in the acoustic matching layer 51 expands as the distance from the piezoelectric element 25 increases.

(3) Operation of Ultrasonic Device Next, the operation of the ultrasonic diagnostic apparatus 11 will be briefly described. A pulse signal is supplied to the piezoelectric element 25 in transmitting ultrasonic waves. The pulse signal is supplied to the element 23 for each column through the lower electrode terminals 35 and 37 and the upper electrode terminals 34 and 36. In each element 23, an electric field acts on the piezoelectric film 28 between the lower electrode 27 and the upper electrode 26. The piezoelectric film 28 vibrates at an ultrasonic frequency. The vibration of the piezoelectric film 28 is transmitted to the vibration film 24. In this way, the vibrating membrane 24 vibrates ultrasonically. As a result, a desired ultrasonic beam is emitted toward an object (for example, the inside of a human body).

  The ultrasonic reflected wave vibrates the vibration film 24. The ultrasonic vibration of the vibration film 24 causes the piezoelectric film 28 to vibrate at a desired frequency. A voltage is output from the piezoelectric element 25 according to the piezoelectric effect of the piezoelectric element 25. In each element 23, a potential is generated between the upper electrode 26 and the lower electrode 27. The potential is output as an electrical signal from the lower electrode terminals 35 and 37 and the upper electrode terminals 34 and 36. In this way, ultrasonic waves are detected.

  Transmission and reception of ultrasonic waves are repeated. As a result, linear scan and sector scan are realized. When the scan is completed, an image is formed based on the digital signal of the output signal. The formed image is displayed on the screen of the display panel 15.

  When the element 23 is ultrasonically vibrated during transmission of ultrasonic waves, the ultrasonic waves are transmitted from the element 23 through the acoustic matching layer 51 and emitted from the surface of the acoustic lens 52. At this time, since the acoustic lens 52 has an acoustic impedance close to the acoustic impedance of the living body, reflection of ultrasonic waves is suppressed at the interface between the acoustic lens 52 and the living body. The acoustic matching layer 51 matches the acoustic impedance between the element 23 and the living body. As a result of the acoustic impedance matching, the reflection of ultrasonic waves at the interface of the acoustic matching layer 51 is reduced.

  In adjacent elements 23, ultrasonic vibration propagates in the acoustic matching layer 51 from one element 23 toward the other element 23. Since the proportion of the occupied volume of the filler 58 is large between the adjacent elements 23, the ultrasonic vibration is efficiently attenuated. Propagation of ultrasonic vibration from one element 23 toward the other element 23 is prevented. Thus, crosstalk is prevented between the adjacent elements 23. Since the base material 57 of the acoustic matching layer 51 is continuous between the adjacent elements 23, reflection of ultrasonic vibration is suppressed. The irregular reflection of ultrasonic waves is suppressed. The accuracy of ultrasonic measurement is improved.

  The ultrasonic vibration propagates in the acoustic matching layer 51 while spreading from the element 23. As described above, if the first region 57a in which the volume occupied by the filler 58 is small in the acoustic matching layer 51 increases as the distance from the piezoelectric element 25 increases, the ultrasonic vibration entering the second region 57b in which the filler 58 has a high occupied volume is It is suppressed. In this way, the irregular reflection of the ultrasonic wave is further effectively suppressed.

(4) Method for Manufacturing Ultrasonic Device Next, a method for manufacturing the ultrasonic device 17 will be briefly described. As shown in FIG. 6, a substrate 61 is prepared. The substrate 61 has an element array 22 including a plurality of elements 23 arranged in an array on a base material 62. The base material 62 corresponds to the base body 21 described above. An opening 46 is formed in the base material 62. A backing material 56 is bonded to the back surface of the substrate 62. The first wiring board 38 and the second wiring board 41 are fixed to the substrate 61.

  Thereafter, the acoustic matching layer 51 is formed on the surface of the substrate 61. In forming the acoustic matching layer 51, first, as shown in FIG. 7, a first material 63 is applied to a region between adjacent elements 23 in a plan view in the thickness direction of the substrate 61. For example, an inkjet technique can be used for applying the first material 63. The droplet of the first material 63 tapers as it moves away from the surface of the substrate 61 due to the surface tension. In the first material 63, the filler 58 is dispersed in the fluid 64 of the silicone resin. In the first material 63, the filler 58 has a second average particle diameter. The applied first material 63 is semi-cured.

  Subsequently, as shown in FIG. 8, the second material 65 is applied to a region between the adjacent first materials 63. In the case of applying the second material 65, an inkjet technique may be used similarly. The second material 65 fills the space between the first materials 63. In the second material 65, the filler 58 is dispersed in the fluid 66 of the silicone resin. In the second material 65, the filler 58 has a first average particle diameter. If the first raw material 63 and the second raw material 65 have approximately the same number of particles of the filler 58 per unit volume, the first raw material 63 has the filler 58 per unit volume in the fluid 66 compared to the second raw material 65. The proportion of occupied volume is large.

  When the second material 65 is applied, the acoustic lens 52 is installed on the first material 63 and the second material 65. The acoustic lens 52 is in close contact with the first material 63 and the second material 65. When the first material 63 and the second material 65 are cured, the acoustic lens 52 is fixed to the substrate 61. The first material 63 corresponds to the second region 57 b of the acoustic matching layer 51, and the second material 65 corresponds to the first region 57 a of the acoustic matching layer 51.

  At this time, since the first material 63 is formed in a tapered shape as the distance from the surface of the substrate 61 increases, mixing of the first material 63 and the second material 65 is prevented according to the semi-curing of the first material. Then, the second material 65 can be formed in a shape that expands away from the element 23. The region where the proportion of the occupied volume of the filler 58 is small can have a shape that widens as the distance from the element 23 increases.

(5) Acoustic matching layer according to the second embodiment As shown in FIG. 9, the acoustic matching layer 71 according to the second embodiment includes a base material 72 and fillers 73a and 73b. The fillers 73 a and 73 b are dispersed in the base material 72. Base material 72 is formed of a silicone resin. The base material 72 continues throughout the acoustic matching layer 71. For the fillers 73a and 73b, for example, at least one selected from the group consisting of zinc oxide powder, zirconium oxide powder, alumina powder, silica powder, titanium oxide powder, silicon carbide powder, aluminum nitride powder, carbon powder and boron nitride powder is used. . The first filler 73a has a first average particle size. The second filler 73b has a second value average particle size larger than the first value. The first filler 73 a is unevenly distributed in the range of the vibration film 24 of the element 23. The second filler 73b is unevenly distributed in a region between the adjacent elements 23. Here, the number of the 1st filler 73a per unit volume and the 2nd filler 73b is substantially equal. As a result, the ratio of the occupied volume of the filler per unit volume between the adjacent elements 23 is larger than the range of the elements 23 in a plan view in the thickness direction of the base 21. Such an acoustic matching layer 71 is incorporated in the ultrasonic device 17 in place of the acoustic matching layer 51 described above.

  When transmitting ultrasonic waves, ultrasonic vibration propagates in the acoustic matching layer 71 from one element 23 toward the other element 23 in the adjacent elements 23. Since the proportion of the occupied volume of the second filler 73b is larger between the adjacent elements 23 than the first filler 73a, the ultrasonic vibration is efficiently attenuated. Propagation of ultrasonic vibration from one element 23 toward the other element 23 is prevented. Thus, crosstalk is prevented between the adjacent elements 23. Since the base material 72 of the acoustic matching layer 71 is continuous between the adjacent elements 23, reflection of ultrasonic vibration is suppressed. The irregular reflection of ultrasonic waves is suppressed. The accuracy of ultrasonic measurement is improved.

  In manufacturing the ultrasonic device 17, the acoustic matching layer 71 is formed on the surface of the substrate 61. In forming the acoustic matching layer 71, first, as shown in FIG. 10, a fluid material 75 is applied to the surface of the substrate 61. The material 75 includes a first filler 73a and a second filler 73b. The 1st filler 73a is formed with the powder of the particle size range of the 1st value. The second filler 73b is formed of a powder having a particle size range of a second value larger than the first value. The material 75 covers the element array 22.

  After the material 75 is applied, ultrasonic vibration is generated in each element 23. As shown in FIG. 11, a standing wave 76 is generated in the material 75. When the ultrasonic vibration is applied at the selected specific frequency, the second filler 73b moves from the region of the vibration film 24 toward the region between the adjacent vibration films 24 based on the ultrasonic vibration. Thus, the second filler 73b is unevenly distributed in a region between the adjacent vibrating membranes 24.

  By adjusting the application time of the ultrasonic vibration, the ratio of the occupied volume of the second filler 73b can have a gradient. The ratio of the occupied volume of the second filler 73b gradually changes from the region of the vibration film 24 toward the region between the adjacent vibration films 24. As a result, an abrupt change in acoustic impedance within the acoustic matching layer 71 is avoided. Therefore, reflection of ultrasonic vibration based on a sudden change in acoustic impedance is effectively suppressed. In this way, irregular reflection of ultrasonic waves is reliably suppressed.

  In addition, as shown in FIGS. 12 and 13, in the acoustic matching layers 51 and 71, the number of fillers 77 can be used for adjusting the ratio of the occupied volume. In the base material 78, fillers 77 having substantially the same particle diameter are dispersed. In the region of the vibration film 24, the number of fillers 77 is small, and in the region between the adjacent vibration films 24, the number of fillers 77 is large. If the number of fillers 77 increases, the proportion of occupied volume increases, and attenuation of ultrasonic vibration propagating through the acoustic matching layers 51 and 71 is promoted. Crosstalk is prevented between adjacent elements 23.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Therefore, all such modifications are included in the scope of the present invention. For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. In addition, the ultrasonic diagnostic apparatus 11, the apparatus terminal 12, the ultrasonic probe 13, the display panel 15, the housing 16, the base 21, the element 23, the first and second wiring boards 38 and 41, the acoustic matching layers 51 and 71, the acoustics The configuration and operation of the lens 52 and the like are not limited to those described in this embodiment, and various modifications can be made.

  DESCRIPTION OF SYMBOLS 11 Ultrasonic diagnostic apparatus as an electronic device and an ultrasonic imaging apparatus, 12 Processing part (device terminal), 13 Probe (ultrasonic probe), 13a Probe main body, 13b Probe head, 15 Display apparatus (display panel), 16 Case 17 ultrasonic device, 22 element array, 23 ultrasonic transducer element, 44 base material (substrate), 51 acoustic matching layer, 57 base material, 57a first region, 57b second region, 58 filler, 63 first material , 65 second material, 71 acoustic matching layer, 72 base material, 73a first filler, 73b second filler, 77 filler, 78 base material.

Claims (11)

A substrate having an ultrasonic transducer elements of multiple,
An acoustic matching layer formed of a base material and a filler and covering the plurality of ultrasonic transducer elements ;
The ratio of the occupied volume of the filler per unit volume between the adjacent ultrasonic transducer elements is larger than the range of the ultrasonic transducer elements in a plan view in the thickness direction of the substrate, Ultrasonic device to do.   The ultrasonic device according to claim 1, wherein the proportion of the occupied volume of the filler has a gradient between a range of the ultrasonic transducer elements and between the adjacent ultrasonic transducer elements. And an ultrasonic device.   The ultrasonic device according to claim 1, wherein a range of the ultrasonic transducer element in the acoustic matching layer increases as the distance from the ultrasonic transducer element increases.   The ultrasonic device according to any one of claims 1 to 3, wherein an average particle diameter of the filler is larger between the adjacent ultrasonic transducer elements as compared to a range of the ultrasonic transducer elements. Ultrasonic device characterized by.   The ultrasonic device according to any one of claims 1 to 3, wherein the number of fillers between adjacent ultrasonic transducer elements is larger than a range of the ultrasonic transducer elements. And an ultrasonic device.   A probe comprising: the ultrasonic device according to claim 1; and a housing that supports the ultrasonic device.   An electronic apparatus comprising: the ultrasonic device according to claim 1; and a processing unit that is connected to the ultrasonic device and processes an output of the ultrasonic device.   The ultrasonic device according to any one of claims 1 to 5, a processing unit connected to the ultrasonic device, processing an output of the ultrasonic device, and generating an image, and displaying the image An ultrasonic imaging apparatus comprising: a display device. A substrate having an ultrasonic transducer element of several, applying a first material in a region between the ultrasonic transducer elements adjacent to each other in plan view in the thickness direction of the substrate,
Applying a second material in a region where the ultrasonic transducer element is disposed;
With
The method of manufacturing an ultrasonic device, wherein the first material has a larger proportion of filler volume per unit volume in the base material than the second material.   10. The method of manufacturing an ultrasonic device according to claim 9, wherein the second material is filled in a space between the first materials after the first material is cured. A substrate having an ultrasonic transducer element of several, applying flowable material including a second filler of the first filler and the particle size range of the first value is greater than the second value of the particle size range of the first value And covering the plurality of ultrasonic transducer elements with the material,
Each ultrasonic transducer element generates ultrasonic vibrations, and based on the ultrasonic vibrations, the ultrasonic transducer elements that are adjacent from the range of the ultrasonic transducer elements in plan view from the thickness direction of the substrate Moving the second filler toward the region between them, and unevenly distributing the second filler in a region between the adjacent ultrasonic transducer elements;
An ultrasonic device manufacturing method comprising:

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