JP6206033B2 - Ultrasonic transducer device and ultrasonic measurement apparatus - Google Patents

Description

  The present invention relates to an ultrasonic transducer device and an ultrasonic measurement apparatus.

  In the ultrasonic transducer device, a plurality of ultrasonic transducer elements are arranged at a constant arrangement pitch. The narrower the arrangement pitch, the higher the azimuth resolution of the ultrasonic beam, thereby improving the resolution of the ultrasonic image. However, in order to reduce the arrangement pitch, it is necessary to reduce the element size, and there is a problem in that the manufacturing burden increases and the cost increases.

  To deal with this problem, for example, Patent Document 1 discloses a technique in which element rows made up of a plurality of ultrasonic transducer elements arranged in the scan direction are arranged by being displaced in the scan direction by a predetermined pitch.

Japanese Patent Laid-Open No. 10-5215

  However, in this method, since the position of one element row and the position of the next element row are shifted by the element size in the slice direction, the beam direction is shifted, and the resolution of the ultrasonic image is reduced. There's a problem. According to some aspects of the present invention, it is possible to provide an ultrasonic transducer device, an ultrasonic measurement apparatus, and the like that can improve the resolution of an ultrasonic image without reducing the element size.

  One aspect of the present invention is an ultrasonic transducer device that transmits an ultrasonic beam to an object and receives an ultrasonic echo from the object, and is arranged in a zigzag manner along a first direction. 1st ultrasonic transducer element-nth (n is an integer greater than or equal to 2) ultrasonic transducer element, and each ultrasonic wave of said 1st ultrasonic transducer element-said nth ultrasonic transducer element The maximum length of the acoustic transducer element in the first direction is WX, the maximum length in the second direction orthogonal to the first direction is WY, and the kth (k is 1 ≦ k ≦ n−1). An arrangement pitch in the first direction between the (integer) ultrasonic transducer elements and the (k + 1) th ultrasonic transducer elements is PX, and the arrangement pitch in the second direction is PX. When the PY, 0.5 × WX ≦ PX <0.75 × WX, and relates to ultrasonic transducer device located in PY <WY.

  According to one aspect of the present invention, since the arrangement pitch PX in the first direction can be made smaller than the maximum length WX in the first direction of the ultrasonic transducer elements, the interval between the ultrasonic beams in the first direction is set to the element size. Can be made narrower. Furthermore, since the arrangement pitch PY in the second direction can be made smaller than the maximum length WY in the second direction of the ultrasonic transducer elements, the deviation in the slice direction of the ultrasonic beam can be reduced. As a result, it is possible to improve the resolution of the ultrasonic image without reducing the element size.

  In the aspect of the invention, the (k + 1) th ultrasonic transducer element may have the arrangement pitch PX in the first direction and the arrangement pitch PX in the second direction with respect to the kth ultrasonic transducer element. The k + 2th ultrasonic transducer element is disposed at a position displaced by the arrangement pitch PY, and the k + 1th ultrasonic transducer element has the arrangement pitch PX in the first direction and the second direction with respect to the k + 1th ultrasonic transducer element. May be arranged at a position displaced by the arrangement pitch PY in the opposite direction.

  In this way, a plurality of ultrasonic transducer elements can be arranged in a zigzag manner along the first direction with the arrangement pitch PX in the first direction and the arrangement pitch PY in the second direction. As a result, it is possible to efficiently arrange a plurality of ultrasonic transducer elements along the first direction and further improve the resolution of the ultrasonic image without reducing the element size.

  In the aspect of the invention, the (k + 1) th ultrasonic transducer element may have a shape obtained by rotating the kth ultrasonic transducer element by a predetermined angle in plan view.

  In this way, the plurality of ultrasonic transducer elements can be rotated by a predetermined angle and zigzag arranged along the first direction.

  In one embodiment of the present invention, each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element may have a rectangular shape in plan view.

  In this way, a plurality of ultrasonic transducer elements having a rectangular shape can be arranged in a zigzag manner along the first direction.

  In one embodiment of the present invention, each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element has a square shape in plan view, and The ultrasonic transducer elements are arranged so that one diagonal of the square of the ultrasonic transducer elements is along the first direction, and the length of the diagonal of the square of the ultrasonic transducer elements is LA. In this case, the arrangement pitch PX is PX = 0.5 × WX = 0.5 × LA, and the arrangement pitch PY is PY = 0.5 × WY = 0.5 × LA. Good.

  In this way, a plurality of ultrasonic transducer elements having a square shape can be zigzag arranged at an arrangement pitch shorter than the length of the diagonal line.

  In one embodiment of the present invention, each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element may have a circular shape in plan view.

  In this way, it is possible to arrange a plurality of ultrasonic transducer elements having a circular shape in a zigzag manner along the first direction.

  In one aspect of the present invention, when the radius length of each ultrasonic transducer element is RA, the arrangement pitch PX is PX = 0.5 × WX = RA, and the arrangement pitch PY is PY = WY × sin 60 ° = 2 × RA × sin 60 °.

  In this way, a plurality of ultrasonic transducer elements having a circular shape can be arranged in a zigzag manner at an arrangement pitch shorter than the diameter of the circle.

  In the aspect of the invention, each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element may have a triangular shape in plan view.

  In this way, it is possible to arrange a plurality of ultrasonic transducer elements having a triangular shape in a zigzag manner along the first direction.

  In one embodiment of the present invention, each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is a thin film piezoelectric ultrasonic transducer having a single vibration film. It may be an element.

  In this way, the ultrasonic transducer elements can be arranged in a zigzag manner at a high density.

  In one embodiment of the present invention, the ultrasonic transducer element includes a substrate on which a plurality of openings are arranged, and each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element includes the plurality of ultrasonic transducer elements. Each of the first ultrasonic transducer element to the nth ultrasonic transducer element is provided for each of the openings, and each of the ultrasonic transducer elements closes the opening; and A piezoelectric element portion provided on a single vibrating membrane, and the piezoelectric element portion covers a lower electrode provided on the single vibrating membrane and at least a part of the lower electrode. You may have a piezoelectric film provided, and an upper electrode provided so that at least one part of the said piezoelectric film may be covered.

  In this way, by applying a signal voltage between the upper electrode and the lower electrode of the ultrasonic transducer element, it is possible to vibrate the single vibrating membrane and transmit the ultrasonic beam.

  In one embodiment of the present invention, a common electrode line wired along the first direction and a first signal electrode line to an nth signal electrode line wired along the second direction are provided. One of the upper electrode and the lower electrode of each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is connected to the common electrode line, Of the upper ultrasonic transducer element and the lower electrode of the jth ultrasonic transducer element (j is an integer satisfying 1 ≦ j ≦ n) among the first ultrasonic transducer element to the nth ultrasonic transducer element. The other of the first signal electrode line to the nth signal electrode line may be connected to the jth signal electrode line.

  If it does in this way, a transmission signal can be supplied to each ultrasonic transducer element via the 1st-nth signal electrode line. In addition, a reception signal from each ultrasonic transducer element can be output via the first to nth signal electrode lines.

  Moreover, in one aspect of the present invention, when each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element has the rectangular shape in plan view, One of the upper electrode and the lower electrode of the jth ultrasonic transducer element is connected to the common electrode at the rectangular end, and the upper electrode and the lower electrode of the jth ultrasonic transducer element The other of the electrodes may be connected to the jth signal electrode line at the rectangular vertex.

  In this way, a plurality of ultrasonic transducer elements having a rectangular shape can be arranged in a zigzag manner at a high density.

  Another aspect of the present invention relates to an ultrasonic measurement apparatus including the ultrasonic transducer device described above.

1 is a first configuration example of an ultrasonic transducer device. In the first configuration example, two rows of ultrasonic transducer elements are provided. The figure explaining the scanning direction and slice direction of an ultrasonic beam. FIGS. 4A, 4 </ b> B, and 4 </ b> C are diagrams for explaining the relationship between the shape and the arrangement pitch of the ultrasonic transducer elements in the comparative example. FIG. 5A shows an example of the shape and arrangement of elements in the first configuration example of the ultrasonic transducer device. FIG. 5B shows an example of the shape and arrangement of elements in a modification of the first configuration example. FIG. 6A shows an example of the shape and arrangement of elements in the second configuration example of the ultrasonic transducer device. FIG. 6B shows an example of the shape and arrangement of elements in a modification of the second configuration example. FIG. 7A shows an example of the shape and arrangement of elements in the third configuration example of the ultrasonic transducer device. FIG. 7B shows an example of the shape and arrangement of elements in a modification of the third configuration example. The layout example of the 1st structural example of an ultrasonic transducer device. The layout example of the 2nd structural example of an ultrasonic transducer device. 10A and 10B are layout examples of the third configuration example of the ultrasonic transducer device. FIG. 11A and FIG. 11B are configuration examples of ultrasonic transducer elements. 2 is a basic configuration example of an ultrasonic measurement apparatus and an ultrasonic imaging apparatus. 13A and 13B are specific configuration examples of the ultrasonic imaging apparatus. FIG. 13C shows a specific configuration example of the ultrasonic probe.

  Hereinafter, preferred embodiments of the present invention will be described in detail. 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 indispensable as means for solving the present invention. Not necessarily.

1. Ultrasonic Transducer Device FIG. 1 shows a first configuration example of an ultrasonic transducer device 200 of the present embodiment. The ultrasonic transducer device 200 of the present embodiment includes first to nth (n is an integer of 2 or more) ultrasonic transducer elements UE1 to UEn, first to nth signal electrode lines SL1 to SLn, common electrodes. A line CL, signal terminals S1 to Sn, and a common terminal COM are included. Note that the ultrasonic transducer device 200 of the present embodiment is not limited to the configuration of FIG. 1, and some of the components are omitted, replaced with other components, or other components are added. Various modifications are possible.

  The ultrasonic transducer elements UE1 to UEn are, for example, thin film piezoelectric ultrasonic transducer elements, and are arranged on the substrate 60 in a zigzag manner along the first direction (scan direction) D1. The ultrasonic transducer elements UE1 to UEn convert a transmission signal, which is an electric signal, into an ultrasonic wave, and convert an ultrasonic echo from an object (subject) into an electric signal.

  In the first configuration example, each of the ultrasonic transducer elements UE1 to UEn has a rectangular (substantially rectangular) shape in plan view. For example, in FIG. 1, each element of the ultrasonic transducer elements UE1 to UEn has a square (substantially square) shape. Each element is arranged so that one diagonal line of each element is along the first direction (scan direction) D1. That is, each element is arranged so that each square side of each element intersects the first direction D1 at an angle of 45 °. Here, the plan view means that the substrate 60 is viewed from the element formation surface side perpendicular to the element formation surface. Note that the angle between each side of the square of each element and the first direction D1 may not be exactly 45 °.

  The shape of the ultrasonic transducer elements UE1 to UEn in a plan view is not limited to the rectangle illustrated in FIG. 1 and may be a circle (substantially circular) or a triangle (substantially triangular). Details of the shape and arrangement of the ultrasonic transducer elements UE1 to UEn will be described later.

  Note that the ultrasonic transducer elements UE1 to UEn are not limited to thin film piezoelectric elements, and may be, for example, capacitive micromachined ultrasonic transducer elements (CMUTs).

  The first to nth signal electrode lines SL1 to SLn are wired along a second direction (slice direction) D2 orthogonal (substantially orthogonal) to the first direction D1. Further, the common electrode line CL is wired along the first direction D1. One of the upper and lower electrodes (first electrode) of each of the ultrasonic transducer elements UE1 to UEn is connected to the common electrode line CL. Among the ultrasonic transducer elements UE1 to UEn, the other of the upper electrode and the lower electrode (second electrode) of the jth ultrasonic transducer element UEj (j is an integer satisfying 1 ≦ j ≦ n) is the first electrode. To the j-th signal electrode line SLj among the n-th signal electrode lines SL1 to SLn. For example, the first electrode of the fifth ultrasonic transducer element UE5 is connected to the common electrode line CL, and the second electrode is connected to the fifth signal electrode line SL5.

  The common terminal COM and the signal terminals S <b> 1 to Sn are provided along the first direction D <b> 1, for example, at the edge of the substrate 60. The common electrode line CL is connected to the common terminal COM, and the jth signal electrode line SLj is connected to the jth signal terminal Sj.

  The scan direction corresponds to a direction in which an ultrasonic beam is scanned in a scan operation such as a sector scan or a linear scan. The slice direction is a direction orthogonal (crossing) to the scan direction. For example, when a tomographic image is obtained by scanning an ultrasonic beam, the slice direction corresponds to a direction orthogonal to the tomographic image.

  During a transmission period in which ultrasonic waves are emitted, a transmission signal output from the transmission unit 110 described later is supplied to the ultrasonic transducer elements UE1 to UEn via the signal terminals S1 to Sn and the signal electrode lines SL1 to SLn. . In the reception period for receiving the ultrasonic echo signal, the reception signals from the ultrasonic transducer elements UE1 to UEn are transmitted to the receiving unit 120 described later via the signal electrode lines SL1 to SLn and the signal terminals S1 to Sn. Is output.

  A common voltage is supplied to the common terminal COM. The common voltage may be a constant DC voltage, and may not be 0 V, that is, the ground potential (ground potential).

  In the ultrasonic transducer device 200 shown in FIG. 1, the signal terminals S <b> 1 to Sn are provided on both of the two opposing end portions, but may be provided on either one of the end portions.

  FIG. 2 shows a case where two rows of ultrasonic transducer elements UE1 to UEn are provided in the first configuration example of the ultrasonic transducer device 200 of the present embodiment. That is, the ultrasonic transducer device 200 shown in FIG. 2 includes first-row ultrasonic transducer elements UE1a to UEna and second-row ultrasonic transducer elements UE1b to UEnb.

  The first electrodes of the ultrasonic transducer elements UEja and UEjb in the j-th column are connected to any one of the common electrode lines CL1, CL2, and CL3, and the second electrode is connected to the j-th signal electrode line SLj.

  As described above, in the ultrasonic transducer device 200 according to the present embodiment, n ultrasonic transducer elements UE1 to UEn arranged in a zigzag manner may be provided in two rows or three or more rows.

  FIG. 3 is a diagram for explaining the scan direction and the slice direction of the ultrasonic beam UB transmitted from the ultrasonic transducer device 200. The scan direction is a direction in which the ultrasonic beam UB is scanned in a scan operation such as a sector scan or a linear scan. The slice direction is a direction intersecting (for example, orthogonal) to the scan direction. For example, when a tomographic image is obtained by scanning the ultrasonic beam UB, the slice direction is a direction orthogonal to the tomographic image.

  The interval between the ultrasonic beams UB depends on the arrangement pitch of the ultrasonic transducer elements UE1 to UEn arranged in the scanning direction (first direction D1). For example, the narrower the arrangement pitch in the scan direction, the narrower the interval between the ultrasonic beams UB. As the interval between the ultrasonic beams UB becomes narrower, an ultrasonic image (for example, a B-mode image) with higher resolution can be obtained.

  FIG. 4A, FIG. 4B, and FIG. 4C are diagrams for explaining the relationship between the shape and the arrangement pitch of the ultrasonic transducer elements in the comparative example. In the following description, the ultrasonic transducer element is also simply referred to as “element”.

  FIG. 4A shows a case where the elements UE1 to UEn having a rectangular shape in a plan view are arranged along the first direction D1. If the maximum length of the element in the first direction D1 is WX and the maximum length in the second direction D2 is WY, the arrangement pitch PX in the scan direction is equal to WX. Therefore, the arrangement pitch PX in the scan direction cannot be made smaller than the element size.

  FIG. 4B shows a case where the elements UE1 to UEn having a rectangular shape in plan view are arranged in a zigzag manner along the first direction D1. Each element is arranged so that one side of the rectangle of each element is parallel to the first direction D1. The even-numbered elements are arranged at positions displaced by ½ of WX in the first direction D1 with respect to the odd-numbered elements. In this case, the arrangement pitch PX in the scan direction is 0.5 × WX, and the arrangement pitch PY in the slice direction is equal to WY.

  In the arrangement shown in FIG. 4B, the arrangement pitch PX in the scan direction is 0.5 × WX, and therefore the arrangement pitch PX can be made smaller than WX. However, since the position of the odd-numbered element and the position of the even-numbered element are displaced by WY in the slice direction, the ultrasonic beam UB transmitted from the odd-numbered element and the ultrasonic wave transmitted from the even-numbered element. The beam direction is deviated from the sound beam UB. This deviation in the beam direction causes a reduction in the resolution of the obtained ultrasonic image.

  FIG. 4C shows a case where the elements UE1 to UEn having a regular hexagonal shape in a plan view are arranged in a zigzag manner along the first direction D1. Each element is arranged such that one side of the regular hexagon of each element is parallel to the first direction D1. The even-numbered elements are disposed at positions displaced by 0.75 × WX in the first direction D1 and 0.5 × WY in the second direction D2 with respect to the odd-numbered elements. The arrangement pitch PX in the scan direction is 0.75 × WX, and the arrangement pitch PY in the slice direction is 0.5 × WY.

  In the arrangement shown in FIG. 4C, since the arrangement pitch PY in the slice direction is 0.5 × WY, the ultrasonic beam UB transmitted from the odd-numbered elements and the ultrasonic beam transmitted from the even-numbered elements. The deviation of the beam direction from the UB can be reduced. However, since the arrangement pitch PX in the scanning direction is 0.75 × WX, the interval between the ultrasonic beams UB cannot be made as narrow as that shown in FIG.

  The ultrasonic transducer device 200 of the present embodiment solves the problem in the comparative example shown in FIGS. 4 (A), 4 (B), and 4 (C). That is, according to the ultrasonic transducer device 200 of the present embodiment, with respect to the arrangement pitch PX in the scan direction and the arrangement pitch PY in the slice direction, 0.5 × WX ≦ PX <0.75 × WX and PY <WY Each element can be arranged to satisfy the above.

  Below, the shape and arrangement | positioning of the element in the 1st, 2nd, 3rd structural example of the ultrasonic transducer device 200 of this embodiment are demonstrated in detail. The element shape is a shape of an area necessary for arranging one element. For example, not only an area for forming a vibration film or a piezoelectric element but also an area necessary for separation from an adjacent element. The shape also includes.

  FIG. 5A shows an example of the shape and arrangement of elements in the first configuration example of the ultrasonic transducer device 200 of the present embodiment. In the first configuration example, each of the elements UE1 to UEn has a rectangular (substantially rectangular) shape in plan view, and is arranged in a zigzag manner along the scanning direction D1. For example, in FIG. 5A, each of the elements UE1 to UEn has a square (substantially square) shape. Each element is arranged so that one diagonal line of each element UE1 to UEn is along the scan direction D1.

  The maximum length in the scan direction of each element UE1 to UEn is WX, the maximum length in the slice direction D2 is WY, and the kth element kk (k is an integer satisfying 1 ≦ k ≦ n−1) and the k + 1th element UEk + 1 The arrangement pitch in the scan direction is PX, the arrangement pitch in the slice direction is PY, and the length of the diagonal line of each element is LA. When the shape of each element is a square, WX = WY = LA.

  UEk + 1 is arranged at a position displaced from UEk by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the slice direction D2. UEk + 2 is arranged at a position displaced from UEk + 1 by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the direction opposite to the slice direction D2.

  As can be seen from FIG. 5A, PX = 0.5 × WX = 0.5 × LA and PY = 0.5 × WY = 0.5 × LA. That is, PX, WX and PY, WY satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY. Note that PX does not have to be exactly 0.5 times WX, and PY does not have to be exactly 0.5 times WY.

  FIG. 5B shows an example of the shape and arrangement of elements in a modification of the first configuration example. The elements UE1 to UEn shown in FIG. 5B have a rectangular (substantially rectangular) shape in a plan view and are arranged in a zigzag manner along the scanning direction D1, as in FIG. Further, each element is arranged so that one diagonal line of each of the elements UE1 to UEn is along the scan direction D1. However, unlike the case of FIG. 5A, the positions of adjacent sides of two adjacent elements are shifted.

  As can be seen from FIG. 5B, the arrangement pitch PX in the scan direction is larger than 0.5 × WX, and the arrangement pitch PY in the slice direction is smaller than 0.5 × WY. Even in this case, PX, WX and PY, WY can be arranged so as to satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY.

  FIG. 6A shows an example of the shape and arrangement of elements in the second configuration example of the ultrasonic transducer device 200 of the present embodiment. In the second configuration example, each of the elements UE1 to UEn has a circular (substantially circular) shape in plan view, and is arranged in a zigzag manner along the scanning direction D1.

  The maximum length in the scan direction of each element UE1 to UEn is WX, the maximum length in the slice direction D2 is WY, the arrangement pitch in the scan direction between the kth element UEk and the k + 1th element UEk + 1 is PX, and the arrangement pitch in the slice direction Is PY, and the radius of each element is RA.

  UEk + 1 is arranged at a position displaced from UEk by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the slice direction D2. UEk + 2 is arranged at a position displaced from UEk + 1 by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the direction opposite to the slice direction D2.

  As can be seen from FIG. 6A, the arrangement pitch PX is PX = 0.5 × WX = RA, and the arrangement pitch PY is PY = WY × sin 60 ° = 2 × RA × sin 60 °. That is, PX, WX and PY, WY satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY. Note that PX does not have to be exactly 0.5 times WX, and PY does not have to be exactly sin 60 ° times WY.

  FIG. 6B shows an example of the shape and arrangement of elements in a modification of the second configuration example. The elements UE1 to UEn shown in FIG. 6B have a circular (substantially circular) shape in plan view and are arranged in a zigzag manner along the scanning direction D1, as in FIG. 6A. However, unlike the case of FIG. 6A, UEk and UEk + 2 are not in contact.

  As can be seen from FIG. 6B, the arrangement pitch PX in the scan direction is larger than 0.5 × WX, and the arrangement pitch PY in the slice direction is smaller than WY × sin 60 °. Even in this case, PX, WX and PY, WY can be arranged so as to satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY.

  FIG. 7A shows an example of the shape and arrangement of elements in the third configuration example of the ultrasonic transducer device 200 of the present embodiment. In the third configuration example, each of the elements UE1 to UEn has a triangular (substantially triangular) shape in plan view, and is arranged in a zigzag manner along the scanning direction D1. For example, in FIG. 7A, each of the elements UE1 to UEn has an equilateral triangle (substantially equilateral triangle) shape. UEk + 1 has a shape obtained by rotating UEk by 180 ° (a predetermined angle in a broad sense) in plan view.

  The maximum length in the scan direction of each element UE1 to UEn is WX, and the maximum length in the slice direction D2 is WY. WX corresponds to the length of the base of the triangle, and WY corresponds to the height of the triangle. The arrangement pitches PX and PY are defined by the position of the center of gravity of the triangle of each element. This is because, when the triangular vibrating membrane vibrates, it is considered that the center of gravity of the triangle has the largest vibration amplitude.

  UEk + 1 is arranged at a position displaced from UEk by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the slice direction D2. UEk + 2 is arranged at a position displaced from UEk + 1 by the arrangement pitch PX in the scan direction D1 and by the arrangement pitch PY in the direction opposite to the slice direction D2.

  As can be seen from FIG. 7A, the arrangement pitch PX is PX = 0.5 × WX, and the arrangement pitch PY is PY = 1/3 × WY. That is, PX, WX and PY, WY satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY. Note that PX does not have to be exactly 0.5 times WX, and PY does not have to be exactly 1/3 times WY.

  FIG. 7B shows an example of the shape and arrangement of elements in a modification of the third configuration example. The elements UE1 to UEn illustrated in FIG. 7B have a regular triangle shape (triangle in a broad sense) in a plan view and are arranged in a zigzag manner along the scanning direction D1, as in FIG. 7A. UEk + 1 has a shape obtained by rotating UEk by 180 ° (a predetermined angle in a broad sense) in plan view. However, unlike the case of FIG. 7A, the positions of adjacent sides of two adjacent elements are shifted.

  As can be seen from FIG. 7B, the arrangement pitch PX in the scan direction is larger than 0.5 × WX, and the arrangement pitch PY in the slice direction is smaller than 1/3 × WY. Even in this case, PX, WX and PY, WY can be arranged so as to satisfy 0.5 × WX ≦ PX <0.75 × WX and PY <WY.

  As shown in FIGS. 5A to 7B, according to the first, second, and third configuration examples of the ultrasonic transducer device 200 of the present embodiment and the modifications thereof, the k-th Of the ultrasonic transducer element UEk and the (k + 1) th ultrasonic transducer element UEk + 1 in the scanning direction is PX and the arrangement pitch in the slice direction is PY, 0.5 × WX ≦ PX <0. 75 × WX and PY <WY.

  By doing so, the arrangement pitch PX in the scan direction can be made smaller than the size of the element, so that the interval between the ultrasonic beams can be made narrower. In addition, since the arrangement pitch PY in the slice direction can be made smaller than the element size, the deviation of the ultrasonic beam in the slice direction can be further reduced. As a result, it is possible to improve the resolution of the ultrasonic image without reducing the element size.

  Furthermore, according to each modification (FIGS. 5B, 6B, and 7B) of the first, second, and third configuration examples of the ultrasonic transducer device 200 of the present embodiment. The combination of the arrangement pitch PX in the scan direction and the arrangement pitch PY in the slice direction can be designed according to the required resolution. As a result, it is possible to realize an ultrasonic transducer device for acquiring an ultrasonic image having a resolution according to the application and purpose.

  FIG. 8 shows a layout example of the first configuration example of the ultrasonic transducer device 200 of the present embodiment. FIG. 8 shows an element arrangement region AR, a lower electrode layer 21 and an upper electrode layer 22 of each element having a rectangular (substantially rectangular) shape. Although not shown, a piezoelectric film is provided in a region sandwiched between the lower electrode layer 21 and the upper electrode layer 22. The element arrangement area AR is an area necessary for arranging one element, and includes not only an area for forming a vibration film or a piezoelectric element, but also an area necessary for separation from an adjacent element. Therefore, the element arrangement area AR extends further outward than the area where the vibration film and the piezoelectric element are formed.

  The lower electrode layer 21 forms a lower electrode of the piezoelectric element and also forms a common electrode line CL. The upper electrode layer 22 forms an upper electrode of the piezoelectric element and also forms signal electrode lines SL1 to SLn. The lower electrode of the j-th element UEj is connected to the common electrode line CL at the rectangular edge. Further, the upper electrode of the j-th element UEj is connected to the j-th signal electrode line SLj at the rectangular apex. By laying out in this way, a plurality of ultrasonic transducer elements having a rectangular shape can be arranged in a zigzag manner with high density.

  In addition, the structure of the cross section along A-A 'and B-B' of FIG. 8 is shown to FIG. 11 (A) and FIG.11 (B) mentioned later. The element structure will be described in detail with reference to FIGS. 11A and 11B.

  FIG. 9 shows a layout example of the second configuration example of the ultrasonic transducer device 200 of the present embodiment. FIG. 9 shows an element arrangement area AR, a lower electrode layer 21 and an upper electrode layer 22 of each element having a circular (substantially circular) shape. The lower electrode layer 21 forms a lower electrode of the piezoelectric element and also forms a common electrode line CL. The upper electrode layer 22 forms an upper electrode of the piezoelectric element and also forms signal electrode lines SL1 to SLn. A cross-sectional structure along A-A ′ and B-B ′ in FIG. 9 is shown in FIGS.

  10A and 10B show layout examples of the third configuration example of the ultrasonic transducer device 200 of the present embodiment. 10A and 10B show an element arrangement region AR, a lower electrode layer 21, and an upper electrode layer 22 of each element having a triangular (substantially triangular) shape. The lower electrode layer 21 forms a lower electrode of the piezoelectric element and also forms a common electrode line CL. The upper electrode layer 22 forms an upper electrode of the piezoelectric element and also forms signal electrode lines SL1 to SLn. FIGS. 11A and 11B, which will be described later, show cross-sectional structures taken along lines A-A ′ and B-B ′ in FIGS. 10A and 10B.

2. Ultrasonic Transducer Element FIGS. 11A and 11B show a configuration example of the ultrasonic transducer element UE (UE1 to UEn) of the present embodiment. This ultrasonic transducer element UE has a vibration film (membrane, support member) 50 and a piezoelectric element part. The piezoelectric element section includes a lower electrode layer (lower electrode) 21, a piezoelectric layer (piezoelectric film) 30, and an upper electrode layer (upper electrode) 22. Note that the ultrasonic transducer element UE of the present embodiment is not limited to the configuration shown in FIGS. 11A and 11B, and some of the components may be omitted or replaced with other components. Various modifications such as adding other components are possible.

  FIG. 11A is a cross-sectional view showing a cross section taken along the line A-A ′ of FIGS. 8, 9, 10 </ b> A, and 10 </ b> B. FIG. 11B is a cross-sectional view showing a cross section taken along line B-B ′ of FIGS. 8, 9, 10 </ b> A, and 10 </ b> B.

  The ultrasonic transducer element UE is provided for each opening of the plurality of openings 45 provided in the substrate 60. The substrate 60 is, for example, a silicon substrate.

  The element arrangement area AR is an area necessary for arranging one element, and includes not only an area for forming a vibration film or a piezoelectric element, but also an area necessary for separation from an adjacent element. Therefore, as shown in FIGS. 11A and 11B, the element arrangement region AR extends further outward than the region where the vibration film and the piezoelectric element are formed.

  The lower electrode layer 21 is formed on the vibration film 50 as a metal thin film, for example. As shown in FIGS. 11A and 11B, the lower electrode layer 21 extends to the outside of the element arrangement region AR and is connected to the adjacent ultrasonic transducer element UE.

  The piezoelectric layer 30 is formed of, for example, a PZT (lead zirconate titanate) thin film, and is provided so as to cover at least a part of the lower electrode layer 21. The material of the piezoelectric layer 30 is not limited to PZT. For example, lead titanate (PbTiO3), lead zirconate (PbZrO3), lead lanthanum titanate ((Pb, La) TiO3), or the like is used. Also good.

  The upper electrode layer 22 is formed of, for example, a metal thin film and is provided so as to cover at least a part of the piezoelectric layer 30. As shown in FIGS. 11A and 11B, the upper electrode layer 22 extends to the outside of the element arrangement region AR and is connected to the adjacent ultrasonic transducer element UE.

  The vibration film (membrane) 50 is provided so as to close the cavity region 40 by a two-layer structure of, for example, a SiO2 thin film and a ZrO2 thin film. The vibration film 50 included in one element is a single vibration film, not an assembly of a plurality of vibration films. A single vibrating membrane is a single vibrating membrane that is vibrated by one piezoelectric element independently of the other vibrating membranes. The vibration film 50 supports the piezoelectric layer 30, the lower electrode layer 21, and the upper electrode layer 22, and can vibrate according to the expansion and contraction of the piezoelectric layer 30 to generate ultrasonic waves.

  The cavity region 40 is formed by etching by reactive ion etching (RIE) or the like from the back surface (surface on which no element is formed) side of the substrate 60 (silicon substrate). The resonance frequency of the ultrasonic wave is determined by the size of the vibration film 50 that can be vibrated by the formation of the cavity region 40, and the ultrasonic wave is radiated to the piezoelectric film 30 side.

  The lower electrode of the ultrasonic transducer element UE is formed by the lower electrode layer 21, and the upper electrode is formed by the upper electrode layer 22. Specifically, a portion of the lower electrode layer 21 covered with the piezoelectric layer 30 forms a lower electrode, and a portion of the upper electrode layer 22 that covers the piezoelectric layer 30 forms an upper electrode. That is, the piezoelectric layer 30 is provided between the lower electrode and the upper electrode.

  The piezoelectric film 30 expands and contracts in the in-plane direction when a voltage is applied between the lower electrode and the upper electrode, that is, between the lower electrode layer 21 and the upper electrode layer 22. The ultrasonic transducer element UE uses a monomorph (unimorph) structure in which a thin piezoelectric element portion and the vibration film 50 are bonded together. When the piezoelectric element portion expands and contracts in the plane, the dimensions of the bonded vibration film 50 are as follows. As it is, warping occurs. Therefore, by applying an AC voltage to the piezoelectric film 30, the vibration film 50 vibrates in the film thickness direction, and ultrasonic waves are emitted by the vibration of the vibration film 50. The voltage applied to the piezoelectric film 30 is, for example, 10 to 30 V, and the frequency is, for example, 1 to 10 MHz.

  The driving voltage of the bulk ultrasonic transducer element is about 100 V from peak to peak, whereas in the thin film piezoelectric ultrasonic transducer element as shown in FIGS. 11 (A) and 11 (B), driving is performed. The voltage can be reduced from the peak to about 10 to 30 V from the peak.

3. Ultrasonic Measuring Device FIG. 12 shows a basic configuration example of the ultrasonic measuring device 100 and the ultrasonic imaging device 400 of the present embodiment. The ultrasonic measurement apparatus 100 of the present embodiment includes an ultrasonic transducer device 200, a transmission unit 110, a reception unit 120, and a processing unit 130. The ultrasonic imaging apparatus 400 includes an ultrasonic measurement apparatus 100 and a display unit 410. Note that the ultrasonic measurement apparatus 100 and the ultrasonic imaging apparatus 400 of the present embodiment are not limited to the configuration shown in FIG. 12, and some of the components are omitted, replaced with other components, or other components. Various modifications, such as adding, are possible.

  The transmission unit 110 performs ultrasonic beam transmission processing. Specifically, the transmission unit 110 generates and amplifies a pulse signal based on the control of the processing unit 130, and outputs a transmission signal (drive signal) that is an electrical signal to the ultrasonic transducer device 200. The ultrasonic transducer device 200 converts a transmission signal, which is an electrical signal, into an ultrasonic wave and transmits the ultrasonic wave. The transmission unit 110 can be configured by, for example, a pulse generator, an amplifier, or the like.

  The reception unit 120 performs reception processing of ultrasonic echoes in which the ultrasonic beam is reflected by the subject. Specifically, the ultrasonic transducer device 200 converts an ultrasonic echo from the subject (object) into an electric signal and outputs the electric signal to the receiving unit 120. The reception unit 120 performs reception processing such as amplification, detection, A / D conversion, and phase matching on the reception signal (analog signal) that is an electrical signal from the ultrasonic transducer device 200, and uses the signal after reception processing. A received signal (digital data) is output to the processing unit 130. The receiving unit 120 can be configured by, for example, a low noise amplifier, a voltage control attenuator, a programmable gain amplifier, a low pass filter, an A / D converter, and the like.

  The processing unit 130 performs control processing for the transmission unit 110 and the reception unit 120 and processing for generating an ultrasound image based on a reception signal from the reception unit 120. The processing unit 130 may be configured with, for example, a dedicated digital signal processor (DSP) or a general-purpose microprocessor (MPU). Alternatively, a part of processing executed by the processing unit 130 may be executed by a personal computer (PC).

  The display unit 410 is a display device such as a liquid crystal display, and receives and displays the display image data generated by the processing unit 130. This display image data includes, for example, an ultrasonic image (B-mode image) or notification information for the user.

4). Ultrasonic Image Device FIGS. 13A and 13B show a specific configuration example of the ultrasonic image device 400 of the present embodiment. FIG. 13A shows a portable ultrasonic imaging apparatus 400, and FIG. 13B shows a stationary ultrasonic imaging apparatus 400.

  Both the portable and stationary ultrasonic imaging devices 400 include an ultrasonic measurement device 100, an ultrasonic probe 300, a cable 350, and a display unit 410. The ultrasonic probe 300 includes the ultrasonic transducer device 200 and is connected to the ultrasonic measurement apparatus 100 by a cable 350. The display unit 410 displays display image data.

  At least a part of the transmission unit 110, the reception unit 120, and the processing unit 130 included in the ultrasonic measurement apparatus 100 may be provided in the ultrasonic probe 300.

  FIG. 13C shows a specific configuration example of the ultrasonic probe 300. The ultrasonic probe 300 includes a probe head 315 and a probe main body 320, and the probe head 315 is detachable from the probe main body 320 as shown in FIG.

  The probe head 315 includes an ultrasonic transducer device 200, a probe base 311, a probe housing 312, and a probe head side connector 313.

  The probe main body 320 includes a probe main body side connector 323. The probe main body side connector 323 is connected to the probe head side connector 313. The probe main body 320 is connected to the ultrasonic measurement apparatus 100 by a cable 350. Note that at least a part of the transmission unit 110 and the reception unit 120 included in the ultrasonic measurement device 100 may be provided in the probe main body 320.

  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. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the configurations and operations of the ultrasonic transducer device and the ultrasonic measurement apparatus are not limited to those described in the present embodiment, and various modifications can be made.

21 Lower electrode layer (lower electrode), 22 Upper electrode layer (upper electrode),
30 piezoelectric film (piezoelectric layer), 40 cavity region, 45 opening, 50 vibration film,
60 substrates,
100 ultrasonic measurement device, 110 transmission unit, 120 reception unit, 130 processing unit,
200 ultrasonic transducer device,
300 ultrasonic probe, 311 probe base, 312 probe housing,
313 probe head side connector, 315 probe head,
320 probe body, 323 probe body side connector,
350 cable, 400 ultrasonic imaging device, 410 display unit,
UE1-UEn ultrasonic transducer element, CL common electrode wire,
COM common terminal, SL1-SLn signal electrode line, S1-Sn signal terminal

Claims (7)

An ultrasonic transducer device that transmits an ultrasonic beam to an object and receives an ultrasonic echo from the object,
A first ultrasonic transducer element to n-th (n is an integer of 4 or more) ultrasonic transducer elements arranged along a first direction;
First to nth signal electrode lines connected to each of the first ultrasonic transducer element to the nth ultrasonic transducer element ,
Each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element has a rectangular shape in plan view,
The maximum length in the first direction of each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is WX, and a second orthogonal to the first direction The maximum length in the direction is WY,
The centroid position of the rectangular area of the k-th (k is an integer satisfying 1 ≦ k ≦ n−1) and the centroid position of the rectangular area of the (k + 1) th ultrasonic transducer element. When the distance between the first directions is the arrangement pitch PX and the distance between the second directions is the arrangement pitch PY,
0.5 × WX ≦ PX <0.75 × WX and PY <WY,
The k + 1th ultrasonic transducer element is displaced from the kth ultrasonic transducer element by the arrangement pitch PX in the first direction and the arrangement pitch PY in the second direction. Arranged,
The (k + 2) th ultrasonic transducer element is displaced from the (k + 1) th ultrasonic transducer element by the arrangement pitch PX in the first direction and the arrangement pitch PY in the direction opposite to the second direction. An ultrasonic transducer device, wherein the ultrasonic transducer device is disposed at a position . The ultrasonic transducer device of claim 1 .
Each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element has a square shape in plan view,
Each ultrasonic transducer element is arranged such that one diagonal of the square of each ultrasonic transducer element is along the first direction;
When the length of the diagonal of the square of each ultrasonic transducer element is LA,
The arrangement pitch PX is PX = 0.5 × WX = 0.5 × LA, and the arrangement pitch PY is PY = 0.5 × WY = 0.5 × LA. Transducer device. The ultrasonic transducer device according to claim 1 or 2 ,
Each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is a thin film piezoelectric ultrasonic transducer element having a single vibration film. Ultrasonic transducer device. The ultrasonic transducer device according to claim 3 .
Including a substrate having a plurality of openings disposed thereon;
Each ultrasonic transducer elements of said first ultrasonic transducer element - the n-th ultrasonic transducer elements are provided in the plurality of apertures your capital,
Each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is:
The single vibrating membrane closing the opening;
A piezoelectric element portion provided on the single vibrating membrane,
The piezoelectric element portion is
A lower electrode provided on the single vibrating membrane;
A piezoelectric film provided to cover at least a part of the lower electrode;
An ultrasonic transducer device comprising: an upper electrode provided to cover at least a part of the piezoelectric film. The ultrasonic transducer device according to claim 4 .
Having said first connected the common electrode line to the ultrasonic transducer elements of the ultrasonic transducer elements - the first n,
One of the upper electrode and the lower electrode of each of the ultrasonic transducer elements of the first ultrasonic transducer element to the nth ultrasonic transducer element is connected to the common electrode line,
The upper electrode and the lower electrode of the jth ultrasonic transducer element (j is an integer satisfying 1 ≦ j ≦ n) among the first to nth ultrasonic transducer elements. The other is connected to a jth signal electrode line among the first signal electrode line to the nth signal electrode line. The ultrasonic transducer device according to claim 5 .
One of the upper electrode and the lower electrode of the j-th ultrasonic transducer element is connected to the common electrode at an end portion of the rectangle,
The ultrasonic transducer device, wherein the other of the upper electrode and the lower electrode of the j-th ultrasonic transducer element is connected to the j-th signal electrode line at the vertex of the rectangle. Ultrasonic measuring apparatus comprising an ultrasonic transducer device of any one of claims 1 to 6.

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