JP2014124431A - Acoustic lens, head unit, probe, ultrasonic imaging device, and correction member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic lens, head unit, probe, ultrasonic imaging device, correction member, etc., by which a desired beam shape can be obtained even if ultrasonic emission timing in a slice direction is not the same.SOLUTION: An acoustic lens 500 comprises: a first member 510 formed with the material of a first sonic speed c; and a second member 520 formed with the material of a second sonic speed cdifferent from the first sonic speed c. A direction vertical to a reference face SS1 is defined as a first direction D1 and a direction corresponding to a slice direction DL as a second direction D2. The first member 510 is installed on the first direction D1 side of the second member 520, with a lens structure possessed which has a lens curved surface formed on the first direction D1 side. The second member 520 is a stair shape in a cross section DNM in the face formed by the first direction D1 and the second direction D2. The height xof the stair of the stair shape is different in the end part and in the center part in the second direction D2.

Description

  The present invention relates to an acoustic lens, a head unit, a probe, an ultrasonic imaging apparatus, a correction member, and the like.

  As a general array type ultrasonic probe, a probe in which bulk piezoelectric elements are arrayed one-dimensionally in a scanning direction is known. In such an ultrasonic probe, generally, the beam shape in the scanning direction is converged by electronic focusing, and the beam shape in the slice direction orthogonal to the scanning direction is converged by an acoustic lens (for example, Patent Documents 1 and 2).

JP-A-63-177700 JP-A-8-24256

  Now, assume that ultrasonic transducer elements (for example, thin film piezoelectric elements and capacitive elements) are arranged in a two-dimensional array to form an ultrasonic probe. In this case, since a plurality of elements are arranged along the slice direction, the drive signal input from the end of the element array is delayed toward the center of the element array, and the emission timing of the ultrasonic wave is the end of the element array. The center and the center are different. When a conventional acoustic lens is applied to such an ultrasonic probe, there is a problem that a desired beam shape (for example, a desired focal length and sound pressure) cannot be obtained due to the difference in the emission timing.

  According to some aspects of the present invention, an acoustic lens, a head unit, a probe, and an ultrasonic imaging apparatus that can obtain a desired beam shape even when the emission timing of ultrasonic waves in the slice direction is not the same. And a correction member etc. can be provided.

  One aspect of the present invention includes a first member made of a material having a first sonic velocity and a second member made of a material having a second sonic velocity different from the first sonic velocity. When the surface on the ultrasonic transducer element array side is the reference plane, the direction perpendicular to the reference plane is the first direction, and the direction corresponding to the slice direction of the ultrasonic transducer element array is the second direction, The first member has a lens structure provided on the first direction side of the second member, and a lens curved surface is formed on the first direction side, and the second member includes the first direction and the first direction. The cross section of the surface formed by the second direction has a stepped shape, and the height of the stepped step is related to the acoustic lens that is different between the end portion and the central portion in the second direction.

  According to one aspect of the present invention, the acoustic lens includes a first member and a second member having different sound speeds. The second member has a staircase shape in a cross section at a plane formed by a first direction perpendicular to the reference plane and a second direction corresponding to the slice direction, and the height of the step of the staircase shape is the second height in the second direction. The two members have different heights at the end and the center. This makes it possible to obtain a desired beam shape even when the ultrasonic wave emission timings in the slice direction are not the same.

  In the aspect of the invention, the first sound speed may be higher than the second sound speed, and the height of the staircase shape may gradually decrease from the end toward the center.

  In this way, the height of the step of the second member having a sound speed slower than that of the first member is sequentially lowered from the end portion toward the center portion, so that the ultrasonic wave is transmitted from the first reference surface to the second reference surface. The time to reach is shortened. Accordingly, even when ultrasonic waves are emitted from the ultrasonic transducer element array with different delay times along the slice direction, the delay can be corrected.

  In one aspect of the present invention, the first sound velocity is faster than the second sound velocity, and the height of the step shape is from the first end portion to the second end portion in the second direction. It may be gradually lowered toward the central portion between the end portions, and may be sequentially lowered from the second end portion in the second direction toward the central portion.

  When drive signals are input from both ends of the ultrasonic transducer array along the slice direction of the ultrasonic transducer array, the delay time increases from both ends toward the center. In this regard, according to one aspect of the present invention, the height of the step of the second member having a sound speed slower than that of the first member becomes lower from both end portions toward the central portion, and thus increases from both end sides toward the central portion. The delay time can be corrected.

  In the aspect of the invention, the first sound speed may be slower than the second sound speed, and the height of the step shape may sequentially increase from the end toward the center.

  In this case, the height of the step of the second member having a higher sound speed than the first member is sequentially increased from the end portion toward the central portion, so that the ultrasonic wave is transmitted from the first reference surface to the second reference surface. The time to reach is shortened. Accordingly, even when ultrasonic waves are emitted from the ultrasonic transducer element array with different delay times along the slice direction, the delay can be corrected.

  In the aspect of the invention, the first sound speed is slower than the second sound speed, and the height of the staircase shape is from the first end in the second direction to the first end and the second end. The height may increase sequentially toward the central portion between the portions, and may increase sequentially from the second end portion toward the central portion in the second direction.

  If it does in this way, the height of the step of the 2nd member whose sound speed is quicker than the 1st member will become low toward the center part from both ends. Thereby, when a drive signal is input from both ends of the ultrasonic transducer element array along the slice direction, a delay time that increases from both ends toward the center can be corrected.

  Moreover, in one aspect of the present invention, the ultrasonic transducer element array has a plurality of ultrasonic transducer elements arranged along the slice direction, and is between the second member and the lens curved surface. When a plane parallel to the reference plane is used as the second reference plane, the step height of the step shape is such that the wavefronts of the ultrasonic waves emitted from the plurality of ultrasonic transducer elements are delayed from each other. The height may be set to be uniform on the two reference planes.

  In this way, the delay of the ultrasonic wave emitted from each of the plurality of ultrasonic transducer elements arranged along the slice direction is corrected by the step shape of the acoustic lens, and the wavefront of the ultrasonic wave at the second reference plane Can be arranged. Thereby, the desired ultrasonic beam shape which suppressed the influence of delay is realizable.

  According to another aspect of the present invention, there is provided a head unit of a probe, the ultrasonic wave having the acoustic lens described in any of the above and a plurality of ultrasonic transducer elements arranged along the slice direction. Each step of the step shape relates to a head unit provided corresponding to one or a plurality of elements of the plurality of ultrasonic transducer elements.

  In another aspect of the present invention, a substrate on which the ultrasonic transducer element array is disposed, a first terminal and a second terminal disposed on the substrate, a signal electrode line disposed on the substrate, A first flexible substrate on which a first signal line is disposed, and a second flexible substrate on which a second signal line is disposed, and the signal electrode line includes: The first terminal and the second terminal are connected to the plurality of ultrasonic transducer elements, and one end of the first signal line is connected to the first terminal, and the plurality of ultrasonic waves is connected to the first terminal. A drive signal for driving a transducer element is supplied to the first terminal. One end of the second signal line is connected to the second terminal, and the drive signal is supplied to the second terminal. May be supplied.

  In this way, a plurality of ultrasonic transducer elements arranged along the slice direction can be driven with the drive signals supplied from the first terminal and the second terminal connected to both ends thereof. In this case, the delay of the emission timing of the ultrasonic waves increases from both ends of the plurality of ultrasonic transducer elements toward the center, and the delay can be corrected by the acoustic lens.

  Still another aspect of the present invention relates to a probe including the acoustic lens described in any of the above.

  Still another aspect of the present invention relates to an ultrasonic imaging apparatus including the probe described above and a display unit that displays display image data.

  According to still another aspect of the present invention, there is provided a correction member provided between the acoustic lens member and the ultrasonic transducer element array, the first member formed of a material having a first sonic velocity, and the first sonic velocity. A second member made of a material having a second sound velocity different from that of the first member, wherein the surface of the second member on the ultrasonic transducer element array side is a reference plane, and a direction perpendicular to the reference plane is a first The first member is provided on the first direction side of the second member when the direction corresponding to the slice direction of the ultrasonic transducer element array is the second direction, and the second member Is a stepped shape in a cross section at a plane formed by the first direction and the second direction, and the height of the stepped step is related to different correction members at the end and the center in the second direction. To do.

  According to another aspect of the present invention, the correction member includes a first member and a second member having different sound speeds. The second member has a staircase shape in a cross section at a plane formed by a first direction perpendicular to the reference plane and a second direction corresponding to the slice direction, and the height of the step of the staircase shape is the second height in the second direction. The two members have different heights at the end and the center. By providing this correction member between the acoustic lens member and the ultrasonic transducer element array, it is possible to obtain a desired beam shape even when the emission timing of ultrasonic waves in the slice direction is not the same. .

1A to 1C are configuration examples of an ultrasonic element. The structural example of an ultrasonic transducer device. The typical sectional view of the ultrasonic transducer device and the acoustic lens of a comparative example. Explanatory drawing about the delay of the ultrasonic emission timing. The 1st structural example of the acoustic lens of this embodiment. Sectional drawing of the 1st structural example of the acoustic lens of this embodiment. Sectional drawing of the 2nd structural example of the acoustic lens of this embodiment. An example of the height of a staircase. Simulation results of acoustic analysis. The modification structural example of the acoustic lens of this embodiment. The structural example of the correction member of this embodiment. Configuration example of the head unit. FIG. 13A to FIG. 13C are detailed configuration examples of the head unit. FIG. 14A and FIG. 14B are configuration examples of an ultrasonic probe. 1 is a configuration example of an ultrasonic imaging apparatus.

  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 Element FIGS. 1A to 1C show a configuration example of an ultrasonic transducer element to which the acoustic lens of this embodiment is applied. The ultrasonic transducer element 10 includes a vibration film 50 (membrane, support member) and a piezoelectric element part. The piezoelectric element section includes a first electrode layer 21 (lower electrode), a piezoelectric layer 30 (piezoelectric film), and a second electrode layer 22 (upper electrode).

  FIG. 1A is a plan view of the ultrasonic transducer element 10 formed on the substrate 60 (silicon substrate) as seen from a direction perpendicular to the substrate on the element forming surface side. FIG. 1B is a cross-sectional view showing a cross-section along AA ′ of FIG. FIG. 1C is a cross-sectional view showing a cross section along BB ′ of FIG.

  The first electrode layer 21 is formed on the vibration film 50 as a metal thin film, for example. The first electrode layer 21 may be a wiring that extends to the outside of the element formation region and is connected to the adjacent ultrasonic transducer element 10 as shown in FIG.

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 first electrode layer 21. The material of the piezoelectric layer 30 is not limited to PZT. For example, lead titanate (PbTiO ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La) TiO ₃ ), etc. May be used.

  The second electrode layer 22 is formed of a metal thin film, for example, and is provided so as to cover at least a part of the piezoelectric layer 30. The second electrode layer 22 may be a wiring that extends to the outside of the element formation region and is connected to the adjacent ultrasonic transducer element 10 as shown in FIG.

The vibration film (membrane) 50 is provided so as to close the opening 40 by a two-layer structure of, for example, a SiO ₂ thin film and a ZrO ₂ thin film. The vibration film 50 supports the piezoelectric layer 30 and the first and second electrode layers 21 and 22 and can vibrate according to the expansion and contraction of the piezoelectric layer 30 to generate ultrasonic waves.

  The opening (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 silicon substrate 60. The resonance frequency of the ultrasonic wave is determined by the size of the vibrating membrane 50 that can be vibrated by the formation of the cavity region 40, and the ultrasonic wave is on the piezoelectric layer 30 side (from the back to the front in FIG. 1A). Radiated.

  The first electrode of the ultrasonic transducer element 10 is formed by the first electrode layer 21, and the second electrode is formed by the second electrode layer 22. Specifically, a portion of the first electrode layer 21 covered with the piezoelectric layer 30 forms the first electrode, and a portion of the second electrode layer 22 covering the piezoelectric layer 30 is the second electrode. An electrode is formed. That is, the piezoelectric layer 30 is provided between the first electrode and the second electrode.

  The piezoelectric layer 30 expands and contracts in the in-plane direction when a voltage is applied between the first electrode and the second electrode, that is, between the first electrode layer 21 and the second electrode layer 22. The ultrasonic transducer element 10 uses a monomorph (unimorph) structure in which a thin piezoelectric element (piezoelectric layer 30) and a metal plate (vibrating film 50) are bonded together, and the piezoelectric layer 30 expands and contracts in the plane. Then, warping occurs because the size of the bonded diaphragm 50 remains the same. By applying an AC voltage to the piezoelectric layer 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 layer 30 is, for example, 10 to 30 V, and the frequency is, for example, 1 to 10 MHz.

2. Ultrasonic Transducer Device FIG. 2 shows a configuration example of an ultrasonic transducer device to which the acoustic lens of this embodiment is applied. In the following, a case where the ultrasonic transducer element array 100 is an array of 8 rows and 64 columns is described as an example, but this embodiment is not limited to this, and m and n of m rows and n columns are m. It may be a value other than = 8 and n = 64.

  In addition, as the ultrasonic transducer device 200, a transducer of the type using the piezoelectric element (thin film piezoelectric element) as described above can be adopted, but the present embodiment is not limited to this. For example, a transducer using a capacitive element such as c-MUT (Capacitive Micro-machined Ultrasonic Transducers) may be used.

  A direction DS shown in FIG. 2 is a scanning direction in the scanning operation of the ultrasonic beam, and a direction DL intersecting (for example, orthogonal to) the scanning direction DS is a slicing direction in the scanning operation of the ultrasonic beam.

  The ultrasonic transducer device 200 includes a substrate 60, an ultrasonic transducer element array 100 disposed on the substrate 60, signal electrode lines LS1 to LS64 wired along the slice direction DL on the substrate 60, and a signal. Signal terminals XA1 to XA64 connected to one end of electrode lines LS1 to LS64 and signal terminals XB1 to XB64 connected to the other ends of signal electrode lines LS1 to LS64 are included. The ultrasonic transducer device 200 includes common electrode lines LC1 and LC2 wired along the slice direction DL on the substrate 60, common terminals XC1 and XC2 connected to one end of the common electrode lines LC1 and LC2, and a common Common terminals XC3 and XC4 connected to the other ends of the electrode lines LC1 and LC2, and common electrode lines LY1 to LY8 having one end connected to the common electrode line LC1 and the other end connected to the common electrode line LC2. .

  The ultrasonic transducer element array 100 includes 64 ultrasonic element arrays SR arranged along the scan direction DS, and the ultrasonic element arrays SR include eight super-element arrays SR arranged along the slice direction DL. It has a sonic transducer element. That is, in the ultrasonic transducer element array 100, the ultrasonic transducer elements 10 are arranged in a matrix of 8 rows and 64 columns. Signal electrodes LS1 to LS64 are connected to one electrode (for example, the lower electrode) of the ultrasonic transducer elements 10 in the first to 64th columns, respectively, and the ultrasonic transducer elements 10 in the first to eighth rows are connected. Common electrode lines LY1 to LY8 are connected to the other electrode (for example, the upper electrode).

  In the signal electrode lines LS1 to LS64, one of the first electrode layer 21 and the second electrode layer 22 in FIGS. 1A to 1C extends on the substrate 60 to the signal terminals XA1 to XA64 and XB1 to XB64. It is formed by being formed. Here, “extendedly formed on the substrate 60” means that a conductive layer (wiring layer) is laminated on the substrate by, for example, a MEMS process or a semiconductor process, and at least two points (for example, an ultrasonic transformer) by the conductive layer. (From the transducer element to the signal terminal) is connected. The common electrode lines LY1 to LY8 are formed by extending the other of the first electrode layer 21 and the second electrode layer 22 on the substrate 60 to the common electrode lines LC1 and LC2.

  A drive signal (for example, a pulse signal) for driving the ultrasonic transducer element array 100 is input to the signal terminals XA1 to XA64 and XB1 to XB64. The drive signal is supplied from, for example, a transmission unit 332 described later with reference to FIG. The signal terminals XAi (first terminal) and XBi (second terminal) (i is a natural number satisfying i ≦ 64) connected to the same ultrasonic element array SR have, for example, drive signals having the same timing, phase and amplitude. Is supplied. When the ultrasonic transducer element 10 receives the echo, the received signal is output from the signal terminals XA1 to XA64, XB1 to XB64. This reception signal is received by, for example, the receiving unit 335 described later with reference to FIG. For example, a common voltage is supplied to the common terminals XC1 to XC4 from a processing device 330 described later with reference to FIG.

  In FIG. 2, the case where one ultrasonic element array SR is connected to one channel (one set of signal terminals XAi and XBi) for transmitting and receiving the same signal has been described as an example. However, the present embodiment is not limited to this. Not. That is, a plurality of ultrasonic element rows SR may be connected to one channel. In this case, one signal electrode line is connected to each ultrasonic element row, and the plurality of signal electrode lines are connected to the common signal terminals XAi and XBi.

  In FIG. 2, the case where the common electrode line is commonly connected to each ultrasonic element row has been described as an example, but the present embodiment is not limited to this. For example, a common terminal and a common electrode line may be provided corresponding to each channel.

  FIG. 2 illustrates an example in which the ultrasonic transducer element array 100 is arranged in a matrix of m rows and n columns. However, the present embodiment is not limited to this, and a plurality of unit elements (ultrasonic transducers) are used. Any arrangement may be used as long as the transducer elements 10) are two-dimensionally arranged. For example, the ultrasonic transducer element array 100 may have a staggered arrangement. Here, the matrix arrangement is an m-row / n-column lattice arrangement, and includes not only a case where the lattice is rectangular but also a case where the lattice is deformed into a parallelogram. The staggered arrangement means that m rows of ultrasonic transducer elements and m-1 rows of ultrasonic transducer elements are alternately arranged, and m rows of ultrasonic transducer elements are (2m-1). The ultrasonic transducer elements of m−1 columns arranged in odd rows in the row are arranged in even rows in (2m−1) rows.

3. Comparative Example of Acoustic Lens FIG. 3 schematically shows a cross section along the slice direction DL of the ultrasonic transducer device 200 and the acoustic lens 550 of the comparative example. The depth direction DZ is a direction perpendicular to the scan direction DS and the slice direction DL, and is a normal direction of the ultrasonic wave emission surface of the substrate 60.

  The acoustic lens 550 of the comparative example is assumed to be a general acoustic lens that performs beam formation in the slice direction DL. Such an acoustic lens 550 is designed on the assumption that ultrasonic waves with the same timing (same phase) are emitted at each position in the slice direction DL. For example, in a one-dimensional array using a bulk piezoelectric element, since there is one opening in the slice direction DL, ultrasonic waves having the same phase are emitted at any position in the slice direction DL. In this case, the acoustic lens 550 can converge the ultrasonic beam BM1 to the designed desired focal point FCP.

  On the other hand, in the ultrasonic transducer device 200 of the present embodiment, a plurality of ultrasonic transducer elements (for example, UE1 to UE8 in FIG. 2) are arranged in the slice direction DL, and drive signals are supplied from the signal terminals XAi and XBi at both ends thereof. To do. As will be described later, the timing (phase) of the drive signal has a different delay amount in each element, and the closer to the signal terminals XAi and XBi, the faster the ultrasonic wave is emitted. Therefore, the ultrasonic beam BM2 that has passed through the acoustic lens 550 converges in front of the desired focal point FCP (sound pressure is maximized), and diffuses farther than the convergence point (sound pressure on the front decreases). End up.

  FIG. 4 shows an explanatory diagram about the delay of the emission timing of the ultrasonic waves. FIG. 4 schematically shows the ultrasonic transducer elements UE1 to UE5 arranged along the slice direction DL. For simplicity, m = 5 and the common electrode line is not shown.

  Parasitic capacitances C1 to C5 are generated between the electrodes of the elements UE1 to UE5 by the piezoelectric layer, respectively. The capacitors C1 to C5 are determined according to the area of the piezoelectric layer sandwiched between the lower electrode and the upper electrode. Further, a wiring resistance is generated in the signal electrode line LSi. The wiring resistance between the signal terminal XBi and the element UE1 is R0, the wiring resistance between the elements UE1 to UE5 is R1 to R4, and the wiring resistance between the element UE5 and the signal terminal XAi is R5.

  The parasitic capacitors C1 to C5 and the wiring resistors R0 to R5 form an RC constant circuit, and the drive signals input from the signal terminals XAi and XBi are delayed by the RC constant circuit. That is, the timing at which the pulse of the drive signal is applied is slower in the element UE3 in the center of the column than the elements UE1 and UE5 close to the signal terminals XAi and XBi. Therefore, when the emission timing of the element UE3 is used as a reference, the elements UE1 and UE5 emit ultrasonic waves at a timing faster by the times Δt1 and Δt5, and the elements UE2 and UE3 only have the times Δt2 (<Δt1) and Δt4 (<Δt5). Ultrasonic waves are emitted at a fast timing. The times Δt1 to Δt5 are determined by the values of the parasitic capacitances C1 to C5 and the wiring resistances R0 to R5.

  Due to the difference in the emission timing, the ultrasonic wavefront WM in the cross section along the slice direction DL is not a straight line but a concave shape, which causes unintended convergence (deformation) of the ultrasonic beam.

  FIG. 9 shows the simulation result of the sound pressure characteristics of the ultrasonic beam with respect to the depth. Only the outline will be described here, and details will be described later. The depth on the horizontal axis is a distance in the first direction D1 with the center of the ultrasonic element array as a reference.

  The sound pressure characteristic A1 is a characteristic when there is no delay in the ultrasonic wave emission timing, and the sound pressure characteristic A2 is a characteristic when there is a delay in the ultrasonic wave emission timing. In the sound pressure characteristic A2, the depth at which the maximum sound pressure is reached is closer to the front than the sound pressure characteristic A1, and the sound pressure drop is greater than the sound pressure characteristic A1 at a distance farther than the depth at which the maximum sound pressure is obtained. ing. As described above, when a plurality of ultrasonic transducer elements are arranged along the slice direction DL and a drive signal is supplied from an end thereof, the conventional acoustic lens 550 has a problem that a desired sound field cannot be obtained. .

4). Acoustic Lens of this Embodiment FIGS. 5 and 6 show a first configuration example of an acoustic lens of this embodiment that can solve the above-described problems.

  FIG. 5 is a perspective view when the acoustic lens 500 of the present embodiment is applied to the ultrasonic transducer device 200. The first to third directions D1 to D3 represent directions in the acoustic lens 500, and correspond to the depth direction DZ, the slice direction DL, and the scan direction DS of the ultrasonic transducer device 200, respectively. Hereinafter, the first direction D1 is also referred to as “up”.

  The acoustic lens 500 is a lens that converges ultrasonic waves on the surface formed by the first direction D1 and the second direction D2. That is, in the cross section DNM at the plane formed by the first direction D1 and the second direction D2, the lens has a curved surface with a convex curvature. Further, in the cross section DNM, the acoustic lens 500 has a structure which will be described later with reference to FIG. 6, and this cross sectional structure is formed so as to have the same structure at any position in the third direction D3. In the cross section at the plane formed by the first direction D1 and the third direction D3, the lens curved surface has no curvature, and the acoustic lens 500 does not converge the ultrasonic wave.

  In the present embodiment, the present invention is not limited to this, and the lens curved surface may have a curvature even in a cross section of a surface formed by the first direction D1 and the third direction D3. In the present embodiment, another member such as an acoustic matching layer may be provided between the acoustic lens 500 and the ultrasonic transducer device 200.

FIG. 6 shows a cross-sectional view of the acoustic lens 500 at the cross section DNM. The acoustic lens 500 includes a first member 510 made of a material having a first sound velocity c ₁ and a second member 520 made of a material having a second sound velocity c ₂ . In the following description, an example in which the ultrasonic element array includes ten ultrasonic transducer elements UE1 to UE10 (m = 10) will be described, but the present embodiment is not limited to this. Further, a case where one step of a staircase shape corresponds to one element will be described as an example, but one step of a staircase shape may correspond to a plurality of elements.

The sound speed c ₁ of the first member 510 and the sound speed c ₂ of the second member 520 are different sound speeds. The first member 510 and the second member 520 are made of, for example, silicon resin, and the sound speeds c ₁ and c ₂ can be adjusted higher than that of the silicone resin by mixing metal powder into the silicon resin. Silicon resin generally has a sound velocity of about 1000 m / s, and the sound velocity (average sound velocity) is adjusted depending on, for example, the type of metal mixed in the silicon resin and the concentration of powder. In addition, the speed of sound can be adjusted to be lower than that of silicon resin by mixing glass sphere or plastic sphere containing air in silicon resin.

The second member 520 has a step shape (step structure) in the cross section DNM. Specifically, the height x _i from the reference plane SS1 of stages corresponding to the ultrasonic transducer elements UEi is different for each ultrasonic transducer element. Here, the reference surface SS1 is a surface of the second member 520 orthogonal to the first direction D1, and is a surface facing the substrate 60 when the acoustic lens 500 is combined with the ultrasonic transducer device 200. In the configuration example of FIG. 6, c ₁ > c ₂ , and in this case, the step heights x ₁ and x ₁₀ at the end of the second member 520 are the highest, and the step height x at the center portion. _The height x _i decreases monotonously toward ₅ and x ₆ .

More specifically, it holds the following equation (1) the height x _i of the step, which sets the height x _i of the step by the following equation (2) obtained by solving for x _i. Here, x _M is the height of the highest step, and in the example of FIG. 6, x _M = x ₁ (x ₁₀ ). Further, t _i is a delay time at which the element UEi emits an ultrasonic wave when the element UE1 (UE10) at the end portion emits an ultrasonic wave as a reference. t _M is the time during which the ultrasonic wave propagates from the reference surface SS1 to the height x _M (the highest step).

上式（１）、（２）によれば、素子ＵＥ１〜ＵＥ１０から出射された超音波は、高さｘ_ｉの違いによって遅延時間ｔ_ｉが補正され、基準面ＳＳ２に同一タイミングで到達する。ここで基準面ＳＳ２は、基準面ＳＳ１に平行な面であり、例えば第２部材５２０の最も高い段に接する面である。ｃ_１＞ｃ_２の場合には、第２部材５２０の方が音速が遅いため、端部ほど超音波の通過時間が長くなり、中央部ほど超音波の通過時間が短くなる。そのため、出射タイミングが速い端部と出射タイミングが遅い中央部との遅延時間が相殺され、基準面ＳＳ２で波面が平坦になる。これにより、基準面ＳＳ２よりも上では従来の音響レンズ（例えば図３の音響レンズ５５０）と同様に考えることができ、波面がそろっているものとして設計したレンズ曲率で所望のビーム形状（例えば図３の超音波ビームＢＭ１）を得ることができる。

The above equation (1), according to (2), ultrasonic wave emitted from the device UE1~UE10, the delay time _{t i} the difference in height _{x i} is the correction, reached at the same timing reference surface SS2. Here, the reference surface SS2 is a surface parallel to the reference surface SS1, for example, a surface in contact with the highest step of the second member 520. In the case of c ₁ > c ₂ , since the second member 520 has a slower sound speed, the ultrasonic wave passage time becomes longer at the end portion and the ultrasonic wave passage time becomes shorter at the central portion. For this reason, the delay time between the end portion with the fast emission timing and the central portion with the slow emission timing is offset, and the wavefront becomes flat at the reference surface SS2. Thus, above the reference surface SS2, it can be considered in the same way as a conventional acoustic lens (for example, the acoustic lens 550 in FIG. 3), and a desired beam shape (for example, FIG. 3) with a lens curvature designed to have a uniform wavefront. 3 ultrasonic beams BM1) can be obtained.

In the above description, the case of c ₁ > c ₂ has been described as an example, but c ₁ <c ₂ may be used. FIG. 7 shows a _second configuration example of the acoustic lens 500 as a configuration example in the case of c ₁ <c ₂ . In the case of c ₁ <c ₂ , the step heights x ₅ and x ₆ at the center portion of the second member 520 are the highest, and the step heights x ₁ and x ₁ at the end portions are increased toward the height. x _i decreases monotonously. Specifically, x _M = x ₅ (x ₆ ), and the step height x _i is set by the above equation (2). Also in this case, the delay of the ultrasonic wave in the slice direction DL is corrected, and the wavefront can be flattened at the reference plane SS2.

Figure 8 _shows an example of a height _{x i} of the step staircase shape when c 1> _{c 2} (FIG. 6). In FIG. 8, 20 ultrasonic elements UE1 to UE20 are arranged in the slice direction DL, the first member 510 having a curved lens surface is formed of a material having a sound velocity of 1000 m / s, and the step-shaped second member 520 is It is made of a material having a speed of sound of 800 m / s. The height of the highest step is x _M = 0.5 mm.

Delay time, elements of the end UE1 to (UE 20) as the reference, the delay time t _i of the timing of the drive signal reaches the respective elements. Delay time t _i is the value calculated by the circuit simulation. The arrival time is a time t _M required for the ultrasonic wave to reach the reference plane SS2 in the end element UE1 (UE20), and a time 625 ns required for the ultrasonic wave having a speed of 800 m / s to pass 0.5 mm. It is. Height x _i of the second member 520 is a value obtained by substituting these values into the above equation (2), the time required for ultrasonic waves from the reference surface SS1 to the reference plane SS2 is propagated in each element The sum of (the second term + the third term in the above equation (1)) and the delay time t _i is such a height that the arrival time t _M is obtained.

  FIG. 9 shows a simulation result of acoustic analysis performed by the acoustic lens 500 having the step shape of FIG. Outside the acoustic lens 500, it is assumed that the ultrasonic beam propagates in water at a sound velocity of 1500 m / s. The depth on the horizontal axis is the distance in the first direction D1 (depth direction DZ) with reference to the center of the ultrasonic element array (the center of UE10 and UE11).

In the sound pressure characteristic A1, the delay time t _{i of} FIG. 8 does not occur (t _i = 0), and the beam is converged by the lens structure above the reference plane SS2 without using the delay correction structure of the present embodiment. The case characteristics. The sound pressure characteristic A2 is a characteristic when the beam is converged by a lens structure above the reference plane SS2 without using the delay correction structure of the present embodiment when the delay time t _{i of} FIG. 8 occurs. . In the sound pressure characteristic A2, it can be seen that the sound pressure at a depth deeper than the depth of the maximum sound pressure is lower than the ideal sound pressure characteristic A1.

Sound pressure characteristic A3 is generated the delay time t _i of FIG. 8 is a characteristic in the case where is the beam converged by the acoustic lens 500 of the present embodiment using the delay compensation structure of FIG. In the sound pressure characteristic A3, the sound pressure at a depth deeper than the depth of the maximum sound pressure is improved, and a characteristic that substantially matches the ideal sound pressure characteristic A1 is obtained.

According to the above embodiments, the acoustic lens 500 includes a first member 510 formed of a first acoustic velocity c ₁ material, first the first sound velocity c ₁ is formed with a different second sound velocity c ₂ material Two members 520. The surface of the second member 520 on the ultrasonic transducer element array 100 side is the reference plane SS1, the direction perpendicular to the reference plane SS1 is the first direction D1, and the direction corresponds to the slice direction DL of the ultrasonic transducer element array 100. Is the second direction D2. In this case, the first member 510 has a lens structure provided on the first direction D1 side of the second member 520 and having a lens curved surface formed on the first direction D1 side. The second member 520 has a step shape in a cross section DNM on a surface formed by the first direction D1 and the second direction D2. Height x _i of the step of the staircase shape is different de end in the second direction D2 (e.g. stages corresponding to elements UE1 in FIG. 6) the central portion (stages corresponding to elements UE 5).

  In this way, since two types of members having different sound velocities are combined at different heights, the time required for the ultrasonic waves emitted from the respective elements to reach the reference surface SS2 from the reference surface SS1 can be varied. Due to the difference in time, the curvature of the ultrasonic wavefront described with reference to FIGS. 3 and 4 is corrected, and the ultrasonic wavefront can be flattened at the reference surface SS2, and the sound pressure at the front of the probe as described with reference to FIG. Reduction can be suppressed.

  If the second member 520 has a smoothly curved shape rather than a stepped shape, the ultrasonic wave passes through the surface obliquely and is refracted, so that the wavefront may not be flat at the reference surface SS2. In this regard, in the present embodiment, since the second member 520 has a staircase shape, the ultrasonic wave emitted from each element passes through the step surface vertically. Thereby, the wavefront can be flattened at the reference plane SS2.

Here, the reference surface SS1 is the surface of the second member 520, and faces the surface of the ultrasonic transducer device 200 that emits ultrasonic waves when the acoustic lens 500 and the ultrasonic transducer device 200 are combined. Surface. The second reference plane SS2 is a plane between the second member 520 and the lens curved surface of the first member 510, and is a plane parallel to the reference plane SS1 on the first direction D1 side of the reference plane SS1. For example, the surface is a distance x _M (the height of the highest step of the staircase shape) from the reference surface SS1. Further, the staircase shape is a shape in which the step height x _i (distance from the reference plane SS1 to the step) is different in each step. For example, the step height x _i is sequentially increased or decreased. is there. Alternatively, a section in which the step height x _i increases (elements UE6 to UE10 in FIG. 6) and a section in which the step height x _i decreases (elements UE1 to UE5) may be combined.

In this embodiment also, the first acoustic velocity c ₁ is faster than the second speed of sound c _2, the height x _i of the step of the staircase shape, the central portion ends (e.g., stages corresponding to elements UE1 in FIG. 6) It becomes lower sequentially toward (the stage corresponding to the element UE5). More specifically, the height x _i of the step staircase shape becomes successively lower first end portion in the second direction D2 from (stages corresponding to elements UE1) toward the center portion, in the second direction D2 It becomes lower sequentially from the second end (the stage corresponding to the element UE10) toward the center. The central portion is a portion between the first end portion and the second end portion (the stage corresponding to the elements UE5 and UE6).

As described with reference to FIG. 4, when drive signals are input from the terminals XAi and XBi at both ends, the delay increases from both ends of the ultrasonic element array toward the center. According to this embodiment, the height x _i of the slow stage of the second member 520 of sound velocity, it becomes successively lower toward the center from the end and a second end, the second reference plane closer to the central portion The time to reach SS2 is shortened, and the above delay can be corrected.

In the present embodiment, the first acoustic velocity c ₁ is slower than the second speed of sound c _2, the height x _i of the step of the staircase shape, the central portion ends (e.g., stages corresponding to elements UE1 in FIG. 7) The height may increase sequentially toward (the stage corresponding to the element UE5). More specifically, the height x _i of the step of the staircase shape is sequentially increased first end in the second direction D2 from (stages corresponding to elements UE1) toward the center portion, in the second direction D2 The second end portion (the step corresponding to the element UE10) may be gradually lowered toward the central portion. The central portion is a portion between the first end portion and the second end portion (the stage corresponding to the elements UE5 and UE6).

In this way, the height x _i fast stage of the second member 520 of sound velocity, it becomes successively higher toward the center from the end and a second end, the second reference surface SS2 closer to the center portion It is possible to correct a delay that becomes shorter as it reaches the center and becomes closer to the center.

Note above the height x _i of the step of the staircase shape in the embodiment but has been described an example in which sequentially becomes lower (or higher) toward the center from the end and a second end, the present embodiment in this It is not limited. That is, as shown in FIG. 10, the height x _i stages, gradually decrease from the end (stages corresponding to elements UE1) towards (stage corresponding to element UE 5) central portion (or higher) will further It may be lower (or higher) sequentially from the center toward the second end (the stage corresponding to the element UE10).

In this case, a drive signal is supplied only to the signal terminals XB1 to XB64 on one end side of the ultrasonic transducer device 200 shown in FIG. In FIG. 10, when a drive signal is supplied from the element UE1 side at one end, the delay of the drive signal increases from the element UE1 toward the UE10. Therefore, the height x _i of the slow stage of the second member 520 of sound velocity, that become successively lower towards the end of (UE1 side) to the second end (UE 10 side), the closer to the second end 2 The time to reach the reference plane SS2 is shortened, and the delay can be corrected so that the wavefront becomes flat at the reference plane SS2.

5. Correction Member In the above embodiment, the case where the acoustic lens 500 has a delay correction structure has been described as an example. However, the present embodiment is not limited to this, and the correction member and the acoustic lens member may be configured separately. . FIG. 11 shows a configuration example of the correction member in this case.

The correction member 530 is provided between the acoustic lens member 540 and the ultrasonic transducer device 200. Correcting member 530 includes a first member 510 formed of a first acoustic velocity _{c 1} material, and the second member 520 includes a first acoustic velocity _{c 1} is formed with a different second sound velocity _{c 2} material. The first member 510 is provided on the first direction D1 side of the second member 520. The second member 520 is a stepped shape in cross section in the plane first direction D1 and the second direction D2 forms, the height x _i of the step of the staircase shape, the end of the second direction D2 (e.g., device UE1 And a central portion (a step corresponding to the element UE5).

The first member 510 and the second member 520 are formed using, for example, a silicon resin as in the configuration example of the acoustic lens 500 described above. Height x _i of the step of the staircase shape is set by the method described in the above equation (2), the wavefront of the ultrasonic wave each element emitted is set to be flat in the second reference plane SS2. Here, the second reference surface SS2 is a surface of the correction member 530 on the first direction D1 side. For example, when the correction member 530 and the acoustic lens member 540 are directly bonded together, the bonded surface is the second reference surface SS2. Although FIG. 11 illustrates the case where the step height x _i decreases from both ends toward the center, the present invention is not limited to this, and the step height x _i increases from both ends toward the center. It may be lower (higher) from one end to the other end.

The acoustic lens member 540 is formed of a third sonic material (for example, silicon resin), and has a curved lens surface on the first direction D1 side. The curvature of the lens curved surface is set so as to realize a desired focal length when the wavefronts are aligned on the second reference surface SS2. The third sound speed is, for example, the same as the first sound speed c ₁ of the first member 510. In this case, the shape of the acoustic lens member 540 is higher than the second reference surface SS2 of the first member 510 of FIG. Can be the same shape. The third acoustic velocity may be sound velocity different from the first acoustic velocity c _1. Further, another layer (for example, an acoustic matching layer) may be provided between the acoustic lens member 540 and the correction member 530.

  As described above, even when the correction member 530 and the acoustic lens member 540 are configured separately, the ultrasonic wave delay can be corrected by the correction member 530 having a stepped shape formed of members having different sound speeds.

6). Head Unit FIG. 12 shows a configuration example of a head unit 220 to which the acoustic lens of this embodiment is applied. A head unit 220 shown in FIG. 12 includes an ultrasonic transducer device 200 (hereinafter also referred to as “element chip”), a connection portion 210, and a support member 250.

  The element chip 200 corresponds to the ultrasonic transducer device described in FIG. The element chip 200 includes an ultrasonic transducer element array 100, a first terminal group XA1 to XA64 including a first terminal XAi, a second terminal group XB1 to XB64 including a second terminal XBi, and a common terminal. XC1 to XC4. The element chip 200 is electrically connected to a processing apparatus (for example, the processing apparatus 330 in FIG. 15) included in the probe main body via the connection unit 210.

  The connection part 210 electrically connects the probe main body and the head unit 220. The connection unit 210 includes a first connector 421, a second connector 422, a first flexible substrate 130, a second flexible substrate 140, and a first integrated circuit device provided on the first flexible substrate 130. 110 and the second integrated circuit device 120 provided on the second flexible substrate 140.

  The terminal groups XA1 to XA64 are provided on the first side of the element chip 200. On the flexible substrate 130, a first signal line group for connecting the terminal groups XA1 to XA64 and the terminal group of the connector 421 is formed. The first signal line group includes a first signal line connected to the first terminal XAi. A first transmission terminal group of the integrated circuit device 110 is connected to the first signal line group.

  The terminal groups XB1 to XB64 are provided on the second side of the element chip 200. On the flexible substrate 140, a second signal line group for connecting the terminal groups XB1 to XB64 and the terminal group of the connector 422 is formed. The second signal line group includes a second signal line connected to the second terminal XBi. The second transmission terminal group of the integrated circuit device 120 is connected to the second signal line group.

  The integrated circuit device 110 includes a first transmission circuit group that outputs a drive signal to the terminal groups XA1 to XA64 via the first transmission terminal group and the first signal line group. The integrated circuit device 120 includes a second transmission circuit group that outputs a drive signal to the terminal groups XB1 to XB64 via the second transmission terminal group and the second signal line group. These drive signals are output based on a control signal from a processing device (for example, the processing device 330 in FIG. 15).

  The connector 421 has a first connection terminal group. Reception signals from the terminal groups XA <b> 1 to XA <b> 64 are output to the connection terminal group via the first signal line group of the flexible substrate 130. The connector 422 has a second connection terminal group. Reception signals from the terminal groups XB <b> 1 to XB <b> 64 are output to the connection terminal group via the second signal line group of the flexible substrate 140.

  Note that the connecting portion 210 is not limited to the configuration shown in FIG. For example, the connection part 210 may be provided only on the first side of the element chip 200. Alternatively, the connection unit 210 omits the connectors 421 and 422 and receives the first connection terminal group that outputs the reception signals from the first terminal groups XA1 to XA64 and the reception from the second terminal groups XB1 to XB64. And a second connection terminal group that outputs a signal.

  By providing the connection portion 210, the probe main body and the head unit 220 can be electrically connected, and the head unit 220 can be attached to and detached from the probe main body.

  The support member 250 is a member that supports the element chip 200. The specific structures of the element chip 200, the connection part 210, and the support member 250 will be described later.

  13A to 13C show detailed configuration examples of the head unit 220. FIG. 13A shows the second surface SF2 side of the support member 250, FIG. 13B shows the first surface SF1 side of the support member 250, and FIG. 13C shows the side surface side of the support member 250. Indicates. The head unit 220 of the present embodiment is not limited to the configuration shown in FIGS. 13A to 13C, and some of the components may be omitted or replaced with other components. Various modifications such as adding components are possible.

  Connectors 421 and 422 are provided on the first surface SF1 side of the support member 250. One end of each of the flexible boards 130 and 140 is connected to the connectors 421 and 422, respectively. Integrated circuit devices 110 and 120 are provided on the flexible substrates 130 and 140. The connectors 421 and 422 are detachable from the corresponding connectors on the probe main body side.

  The element chip 200 is supported on the second surface SF2 side that is the back surface of the first surface SF1 of the support member 250. The other ends of the flexible substrates 130 and 140 are connected to the terminals of the element chip 200. The fixing member 260 is provided at each corner portion of the support member 250 and is used to fix the head unit 220 to the probe housing.

  Here, the first surface side of the support member 250 is the normal direction side of the first surface SF1 of the support member 250, and the second surface side of the support member 250 is the first surface side of the support member 250. This is the normal direction side of the second surface SF2, which is the back surface of the surface SF1.

  As shown in FIG. 13C, a protective member (protective film) 270 for protecting the element chip 200 is provided on the surface of the element chip 200 (the surface on which the piezoelectric layer 30 is formed in FIG. 1B). It is done. The acoustic lens 500 may also serve as the protection member 270.

7). Ultrasonic Probe FIGS. 14A and 14B show a configuration example of an ultrasonic probe 300 to which the head unit 220 is applied. 14A shows a case where the head unit 220 (probe head) is attached to the probe main body 320, and FIG. 14B shows a case where the head unit 220 is separated from the probe main body 320.

  The head unit 220 includes an element chip 200, a support member 250, a protection member 270, flexible substrates 130 and 140 (not shown), integrated circuit devices 110 and 120 (not shown), a head unit side connector 425, an acoustic lens 500, and a head unit. A housing 240 for storing 220 components is included.

  The probe main body 320 includes a processing device 330, a probe main body side connector 426, and a housing 340 that stores components of the probe main body 320. The processing device 330 includes a receiving unit 335 (analog front end unit) and a transmission / reception control unit 334. The receiving unit 335 and the transmission / reception control unit 334 are realized by, for example, an integrated circuit device provided on a rigid board.

  The reception unit 335 performs reception processing of an ultrasonic echo signal (reception signal) from the ultrasonic transducer element. The transmission / reception control unit 334 controls the integrated circuit devices 110 and 120 and the reception unit 335. The probe main body side connector 426 is connected to the head unit side connector 425. The probe main body 320 is connected to an electronic device (for example, an ultrasonic imaging apparatus) main body by a cable 350.

  Note that although the constituent units described in FIGS. 12 to 13C are stored in the housing 240, the constituent units may be removable from the housing 240. In this way, only the constituent unit can be exchanged. Alternatively, the head unit 220 stored in the housing 240 can be replaced.

8). Ultrasonic Imaging Device FIG. 15 shows a configuration example of an ultrasonic imaging device. The ultrasonic imaging apparatus includes an ultrasonic probe 300 and an electronic device main body 400. The ultrasonic probe 300 includes an ultrasonic head unit 220 and a processing device 330. The electronic device main body 400 includes a control unit 410, a processing unit 420, a user interface unit 430, and a display unit 440.

  For example, a medical ultrasonic diagnostic apparatus is assumed as the ultrasonic imaging apparatus. Alternatively, a diagnostic device that performs nondestructive inspection of an interior of a building or the like, a user interface device that detects movement of a user's finger by reflection of ultrasonic waves, and the like are assumed.

  The processing device 330 includes a transmission / reception control unit 334 and a reception unit 335 (analog front end unit). The ultrasonic head unit 220 includes an element chip 200 (ultrasonic transducer device) and a connection part 210 (connector part) that connects the element chip 200 to a circuit board (for example, a rigid board). A transmission / reception controller 334 and a receiver 335 are mounted on the circuit board. Connection unit 210 includes an integrated circuit device 390. The integrated circuit device 390 includes a transmission unit 332 (pulser).

  When transmitting an ultrasonic wave, the transmission / reception control unit 334 issues a transmission instruction to the transmission unit 332, and the transmission unit 332 receives the transmission instruction, amplifies the drive signal to a high voltage, and outputs the drive voltage. The receiving unit 335 has a limiter circuit (not shown), and the limiter circuit cuts off the drive voltage. When receiving the reflected wave of the ultrasonic wave, the receiving unit 335 receives the reflected wave signal detected by the element chip 200. Based on the reception instruction from the transmission / reception control unit 334, the reception unit 335 processes the reflected wave signal (for example, amplification processing or A / D conversion processing) and transmits the processed signal to the processing unit 420. As a scanning method in transmission / reception, various methods such as linear scanning and sector scanning can be employed. The processing unit 420 visualizes the signal and displays it on the display unit 440.

  In the above embodiment, the case where the integrated circuit device 390 includes only the transmission unit 332 has been described as an example. However, the present embodiment is not limited to this. For example, the integrated circuit device 390 includes the reception unit 335 and the transmission / reception control unit 334. May be included.

  Although the present embodiment has been described in detail as described above, it will be readily 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. All combinations of the present embodiment and the modified examples are also included in the scope of the present invention. Further, the configurations and operations of the acoustic lens, the ultrasonic transducer device, the head unit, the ultrasonic probe, and the ultrasonic imaging apparatus are not limited to those described in the present embodiment, and various modifications can be made.

10 ultrasonic transducer elements, 21 first electrode layer, 22 second electrode layer,
30 piezoelectric layer, 40 aperture, 40 cavity region, 45 aperture, 50 vibrating membrane,
60 substrates, 100 ultrasonic transducer element arrays,
110 first integrated circuit device, 120 second integrated circuit device,
130 first flexible substrate, 140 second flexible substrate,
200 ultrasonic transducer device, 210 connection,
220 head unit, 240 housing, 250 support member,
260 fixing member, 270 protective member, 300 ultrasonic probe,
320 probe body, 330 processing device, 332 transmitter,
334 Transmission / reception control unit, 335 reception unit, 340 housing, 350 cable,
390 integrated circuit device, 400 electronic device main body, 410 control unit,
420 processing unit, 421, 422 connector,
425 Head unit side connector, 426 Probe body side connector,
430 User interface unit, 440 display unit, 500 acoustic lens,
510 first member, 520 second member, 530 correction member,
540 acoustic lens member, 550 acoustic lens,
BM1, BM2 ultrasonic beam, C1-C5 parasitic capacitance,
D1 to D3, first to third directions, DL slice direction, DNM cross section,
DS scan direction, DZ depth direction, FCP focus,
LC1, LC2 common electrode lines, LS1 to LS64 signal electrode lines,
LY1 to LY8 common electrode line, R0 to R5 wiring resistance, SR ultrasonic element array,
SS1 first reference plane, SS2 second reference plane,
UE1-UE10 ultrasonic transducer element, WM wavefront,
XA1 to XA64, XB1 to XB64 signal terminals, XC1 to XC4 common terminals,
c ₁ first sound speed, c ₂ second sound speed, height of _xi stage

Claims (11)

A first member formed of a first sound velocity material;
A second member formed of a second sound velocity material different from the first sound velocity;
Including
The surface of the second member on the ultrasonic transducer element array side is a reference plane, a direction perpendicular to the reference plane is a first direction, and a direction corresponding to the slice direction of the ultrasonic transducer element array is a second direction. If
The first member is provided on the first direction side of the second member, and has a lens structure in which a lens curved surface is formed on the first direction side,
The second member has a step shape in a cross section in a plane formed by the first direction and the second direction,
The acoustic lens according to claim 1, wherein a height of the step of the step shape is different between an end portion and a center portion in the second direction. In claim 1,
The first sound speed is faster than the second sound speed,
The acoustic lens according to claim 1, wherein the height of the staircase shape is gradually decreased from the end portion toward the central portion. In claim 1,
The first sound speed is faster than the second sound speed,
The height of the staircase shape decreases sequentially from the first end in the second direction toward the center between the first end and the second end, and the second in the second direction. An acoustic lens characterized by lowering sequentially from an end toward the center. In claim 1,
The first sound speed is slower than the second sound speed,
The acoustic lens according to claim 1, wherein the height of the staircase shape is sequentially increased from the end toward the center. In claim 1,
The first sound speed is slower than the second sound speed,
The height of the staircase shape sequentially increases from the first end in the second direction toward the center between the first end and the second end, and the second end in the second direction. An acoustic lens characterized by increasing in order from the center toward the center. In any one of Claims 1 thru | or 5,
The ultrasonic transducer element array has a plurality of ultrasonic transducer elements arranged along the slice direction;
When a plane parallel to the reference plane between the second member and the lens curved surface is used as the second reference plane, the height of the step-shaped step is determined from the plurality of ultrasonic transducer elements. An acoustic lens, wherein the wavefront of the ultrasonic wave emitted while being delayed is set to a height at which the second reference plane is aligned. A probe head unit,
An acoustic lens according to any one of claims 1 to 6;
The ultrasonic transducer element array having a plurality of ultrasonic transducer elements arranged along the slice direction;
Including
Each step of the staircase shape is provided corresponding to one or a plurality of elements of the plurality of ultrasonic transducer elements. In claim 7,
An ultrasonic transducer device comprising: a substrate on which the ultrasonic transducer element array is disposed; first and second terminals disposed on the substrate; and a signal electrode line disposed on the substrate; ,
A first flexible substrate on which a first signal line is disposed;
A second flexible substrate on which a second signal line is disposed;
Including
The signal electrode line connects the first terminal and the second terminal and the plurality of ultrasonic transducer elements,
The first signal line has one end connected to the first terminal, and supplies a driving signal for driving the plurality of ultrasonic transducer elements to the first terminal;
One end of the second signal line is connected to the second terminal, and the drive signal is supplied to the second terminal.   A probe comprising the acoustic lens according to claim 1. A probe according to claim 9;
A display unit for displaying image data for display;
An ultrasonic imaging apparatus comprising: A correction member provided between the acoustic lens member and the ultrasonic transducer element array,
A first member formed of a first sound velocity material;
A second member formed of a second sound velocity material different from the first sound velocity;
Including
The surface of the second member on the ultrasonic transducer element array side is a reference plane, a direction perpendicular to the reference plane is a first direction, and a direction corresponding to the slice direction of the ultrasonic transducer element array is a second direction. If the direction
The first member is provided on the first direction side of the second member,
The second member has a step shape in a cross section in a plane formed by the first direction and the second direction,
The height of the step of the staircase shape is different between the end portion and the center portion in the second direction.

Images