Transducer unit, ultrasonic probe, apparatus, and method for manufacturing the transducer unit

Abstract

To provide a vibrator unit that can obtain sufficient output even when the frequency of ultrasonic waves oscillated by a piezoelectric element becomes high frequency.SOLUTION: A vibrator unit 10 includes a first vibrator 1a, and a second vibrator 1b spaced apart from the first vibrator 1a. The first vibrator 1a includes a first piezoelectric element 3a, and a first acoustic matching portion 4a provided on the first piezoelectric element 3a. The second vibrator 1b includes a second piezoelectric element 3b, and a second acoustic matching portion 4b provided on the second piezoelectric element 3b. The distance D1 between the first piezoelectric element 3a and the second piezoelectric element 3b is 10 μm or less, and becomes narrower as it moves away from the first acoustic matching portion 4a and the second acoustic matching portion 4b.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a vibrator unit, an ultrasonic probe, an apparatus, and a method for manufacturing a vibrator unit.

Background Art

[0002] An ultrasonic probe includes a vibrator unit having a plurality of vibrators. Each of the plurality of vibrators includes a piezoelectric element and an acoustic matching section. Patent Documents 1 and 2 disclose that by controlling the shapes of the piezoelectric element and the acoustic matching section, the directivity of ultrasonic waves oscillated by the vibrator can be improved.

[0003] Also, it is known that the resolution of an image obtained from an ultrasonic probe can be increased by increasing the frequency of ultrasonic waves generated by the vibrator unit. To increase the frequency of ultrasonic waves, it is known that the size of the piezoelectric element needs to be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when attempting to reduce the size of the piezoelectric element based on the disclosures of Patent Documents 1 and 2, it may not be possible to obtain sufficient ultrasonic output.

Means for Solving the Problems

[0006] A first aspect for solving the above problems is a first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element. A vibrator unit comprising a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, the second vibrator being positioned at a distance from the first vibrator, When the transducer unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged with a rectangular gap between them. The vibrator unit is characterized in that the distance D1 between the first piezoelectric element and the second piezoelectric element is 10 μm or less, and that the distance narrows as it moves away from the first acoustic matching section and the second acoustic matching section.

[0007] A second embodiment for solving the above problem is a vibrator unit comprising: a first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element; and a second vibrator having a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, and arranged at a distance from the first vibrator, wherein when the vibrator unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged at a rectangular distance apart, and the distance D1 between the first piezoelectric element and the second piezoelectric element narrows as it moves away from the first acoustic matching section and the second acoustic matching section.

[0008] A third embodiment for solving the above problem is a step of installing a first member having a piezoelectric element and an acoustic matching material provided on the piezoelectric element in a chamber, A step of reducing the pressure inside the chamber to below atmospheric pressure, A step of providing a groove in the first member using laser light with a wavelength of 380 nm or less, a first vibrator having a first piezoelectric element and a first acoustic matching portion provided on the first piezoelectric element, and a second vibrator having a second piezoelectric element and a second acoustic matching portion provided on the second piezoelectric element, and being arranged at a distance from the first vibrator, The process of obtaining the aforementioned vibrator unit through the process of providing the second vibrator, This is a method for manufacturing an oscillator unit, characterized by having [a specific feature]. [Effects of the Invention]

[0009] According to the above solution, it is possible to provide a transducer unit that can obtain sufficient output even when the frequency of the ultrasonic waves emitted by the piezoelectric element becomes high. Furthermore, a method for manufacturing the same can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram of an ultrasound diagnostic apparatus according to an embodiment. [Figure 2] A schematic diagram of an ultrasonic probe according to an embodiment. [Figure 3] (a) Perspective view of the transducer unit according to the embodiment. (b) Side view of the transducer unit according to the embodiment. [Figure 4] A schematic diagram of a method for manufacturing a vibrator unit according to an embodiment. [Figure 5] Side view of the oscillator unit of the comparative example. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described below.

[0012] [Device] Figure 1 is a schematic diagram of an ultrasound diagnostic apparatus, which is an example of a device according to the embodiment. The ultrasound diagnostic apparatus 1000 includes an ultrasound probe 100, a main unit 200, a display unit 300, and an input unit 400. In Figure 1, 500 represents the subject (human).

[0013] Figure 2 is a schematic diagram of an ultrasonic probe according to an embodiment. The ultrasonic probe 100 includes a housing 130, a transducer unit 10, a backing material 110, and an acoustic lens 120 inside the housing 130. The ultrasonic probe 100 is detachable from the main body 200. The detailed structure of the transducer unit 10 will be explained with reference to Figures 3 and 4.

[0014] The oscillator unit 10 is provided with a backing material 110 on one side and an acoustic lens 120 on the other side in the direction where the subject 500 is located. The interface between the oscillator unit 10 and the backing material 110 is joined by an adhesive (not shown). Similarly, the interface between the oscillator unit 10 and the acoustic lens 120 is joined by an adhesive (not shown).

[0015] The backing material 110 is made of a material having an acoustic impedance higher than that of the piezoelectric element 3 of the oscillator unit 10 and has a function of transmitting and receiving ultrasonic waves together with the piezoelectric element 3. "Ultrasonic waves" generally refer to elastic vibration waves (sound waves) having a high frequency that cannot be heard by the human ear, but in this specification, they refer to sound waves having a frequency of 20 kHz or higher. The presence of the backing material 110 can suppress spurious vibrations and shorten the pulse width of ultrasonic waves. However, the backing material 110 is not necessarily required when the frequency at which the piezoelectric element 3 oscillates is a high frequency such as 30 MHz or higher. The material of the backing material 110 is not particularly limited, and for example, a resin containing a filler, a cemented carbide such as tungsten carbide can be used.

[0016] The acoustic lens 120 has a function of converging ultrasonic waves transmitted from the piezoelectric element 3 toward the subject 500. In FIG. 2, the surface of the acoustic lens 120 facing the subject 500 is a plane, and the plane is positioned parallel to the tip of the oscillator unit 10. However, the shape of the acoustic lens 120 is not limited to this, and for example, the surface facing the subject 500 may be an arc-shaped surface that protrudes toward the subject 500. In that case, it is preferable that each oscillator 1 of the oscillator unit 10 also has an arc-shaped surface that protrudes toward the subject 500. The material of the acoustic lens 120 is not particularly limited, and for example, rubber mainly composed of a silicone-based resin, silicone rubber can be used.

[0017] Returning to FIG. 1, the main body 200 has a transmission / reception circuit unit 210, an image generation unit 220, and a storage unit 230.

[0018] The main unit 200 controls the transmission and reception of ultrasound waves by the ultrasound probe 100 and has the function of generating an ultrasound image based on the reflected waves received by the ultrasound probe 100. The main unit 200 is connected to the ultrasound probe 100 by a cable (not shown). The ultrasound probe 100 is also detachable from the main unit 200.

[0019] The transmitting and receiving circuit unit 210 has the function of supplying a drive signal, which is an electrical signal, to the ultrasonic probe 100. It also has the function of transmitting the electrical signal to the image generation unit 220 when ultrasonic waves are irradiated into the subject 500 from the ultrasonic probe 100 and the ultrasonic waves reflected from inside the subject 500 are converted back into an electrical signal by the ultrasonic probe 100.

[0020] The image generation unit 220 has the function of generating image data by performing calculations based on the delay time and signal strength changes of the electrical signals output from the transmitting / receiving circuit unit 210. It also has the function of outputting the generated image data to the storage unit 230 and / or the display unit 300.

[0021] The memory unit 230 is, for example, a storage device such as an HDD or SSD, and has the function of storing ultrasound images generated by the image generation unit 220. It also has the function of storing electrical signal data output from the transmission / reception circuit unit 210. Furthermore, it has the function of storing diagnostic information of the subject 500, such as patient ID and medical record information, which is stored in association with the image data.

[0022] The display unit 300 is, for example, a monitor that displays a GUI (Graphical User Interface) for the operator of the ultrasound diagnostic device 1000 to input various setting requests using the input unit 400. It also displays ultrasound images and the like generated by the image generation unit 220.

[0023] The input unit 400 is, for example, a keyboard or touch panel, and receives various setting requests from the operator of the ultrasound diagnostic device 1000 and transfers the received setting requests to the main unit 200. For example, the input unit 400 receives various setting requests for controlling the ultrasound probe 100 and transfers those requests to the transmitting / receiving circuit unit 210.

[0024] [Transducer Unit] Figure 3 is a schematic diagram of the oscillator unit according to the embodiment, where Figure 3(a) is a perspective view and Figure 3(b) is a side view.

[0025] The transducer unit 10 includes transducers 1a, 1b, 1c, and 1d. Transducer 1a is the first transducer, and transducer 1b is the second transducer. Each of the transducers 1 is provided on the conductive layer 2. Each of the transducers 1 also includes a piezoelectric element 3, an acoustic matching section 4, and an acoustic matching section 5. Each of the transducers 1 is arranged at a predetermined interval in the x-direction. The x-direction is the scanning direction of the ultrasonic probe 100 relative to the subject 500.

[0026] When ultrasound is transmitted from the ultrasound probe 100 to the subject 500, the transmitted ultrasound is reflected one after another by discontinuities in acoustic impedance within the subject's internal tissues and received as reflected waves by each transducer 1 of the ultrasound probe 100. The received reflected waves are converted into reflected wave signals, which are electrical signals, by the piezoelectric elements 3 of each transducer 1 that received the reflected waves. The amplitude of the reflected wave signal depends on the difference in acoustic impedance at the discontinuities where the ultrasound is reflected.

[0027] In Figure 3, each of the oscillators 1 has a length in the y-direction that is longer than its length in the x-direction, and the acoustic matching sections 4 and 5 are rectangular parallelepipeds. However, the shape of the oscillator 1 is not limited to this, and the acoustic matching sections 4 and 5 may be cubes. In Figure 3, there are four oscillators, but there may be multiple oscillators, and the number is not limited to this.

[0028] The conductive layer 2 is a component provided on the backing material 110 and has wiring (not shown) for supplying electrical signals to the piezoelectric element 3. The conductive layer 2 is, for example, a component with wiring provided on a polyimide substrate. The wiring can be made of copper or gold. In a configuration without the backing material 110, it can also function as an electrode for the piezoelectric element 3.

[0029] The piezoelectric element 3 comprises a piezoelectric body and a plurality of electrodes. The piezoelectric element 3 generates ultrasonic waves based on a drive signal supplied from the transmitting / receiving circuit unit 210. In the plurality of transducers, each piezoelectric element 3 has the function of receiving reflected waves from the test subject 500 and converting the received reflected waves into electrical signals. The piezoelectric body is, for example, PZT, PMN-PT, PZN-PT, LiNbO3, or BaTiO3, and ceramics or single crystals of these materials can be used. Single crystals are preferred from the viewpoint of having excellent electromechanical coupling coefficients. The plurality of electrodes can be provided, for example, on both sides in the z direction in Figure 3. This is to apply a voltage to the piezoelectric body and transmit the generated ultrasonic waves to the transmitting / receiving circuit unit 210. The material of the electrodes is not particularly limited, and for example, metals such as copper, silver, and gold, alloys, and conductive oxides can be used.

[0030] The piezoelectric elements 3a, 3b, 3c, and 3d are arranged at predetermined intervals in the x-direction, with a maximum distance D1 between piezoelectric elements 3a and 3b. Furthermore, the distance between piezoelectric elements 3a and 3b gradually decreases as the distance from the acoustic matching unit 4 increases. This configuration allows for a larger volume of piezoelectric elements 3a and 3b despite their separation. Therefore, even at high frequencies, the output of the transducer unit can be sufficiently obtained. The distance D1 between adjacent piezoelectric elements is preferably 10 μm or less, in order to further enhance the output of the transducer unit. Additionally, the shorter spacing between each transducer 1 reduces the influence of artifacts caused by the grating globe on the generated ultrasonic image.

[0031] Furthermore, it is preferable that the spacing D1 between adjacent piezoelectric elements is less than or equal to the spacing D2 between adjacent acoustic matching sections 4, which will be described later. This is to avoid contact between adjacent acoustic matching layers 4a and 4b when the piezoelectric element 3 vibrates. If acoustic matching layer 4a and acoustic matching layer 4b come into contact, spurious vibrations may occur, potentially resulting in insufficient accuracy of the ultrasonic image. The spacing between the piezoelectric elements 3 may be filled with a filler. The presence of a filler can increase the mechanical strength of the transducer unit 10. The material of the filler is not particularly limited, but for example, silicone rubber, urethane rubber, and epoxy resin can be used.

[0032] The thickness H1 of the piezoelectric element 3, which is the z-direction length of the piezoelectric element 3 in Figure 3, is preferably 100 μm or less. The frequency of the ultrasonic waves generated by the piezoelectric element 3 depends on the thickness H1, and the thinner the thickness H1, the higher the frequency of the sound waves. A thickness H1 of 50 μm or less is more preferable, as it makes it easier to raise the ultrasonic frequency to 30 MHz or higher. When the ultrasonic frequency is 30 MHz or higher, the resolution of the ultrasonic image becomes sufficiently high. There is no particular lower limit to the thickness H1, but considering the ease of manufacturing, it is preferably 20 μm or more. In addition, the ratio of the thickness H1 to the spacing D1 between adjacent piezoelectric elements is preferably 5 or more. This is to make it less likely for acoustic or electrical coupling to occur between adjacent piezoelectric elements 3a and 3b.

[0033] The acoustic matching units 4 and 5 are positioned between the piezoelectric element 3 and the specimen 500, and have the function of matching their acoustic impedances. An acoustic lens 120 is provided in the direction away from the piezoelectric element 3 of the acoustic matching unit 5. In Figure 3, two acoustic matching units, the acoustic matching unit 4 and the acoustic matching unit 5, are provided, but there may be one acoustic matching unit or three or more.

[0034] The adjacent acoustic matching sections 4a, 5a and 4b, 5b are arranged with a rectangular gap between them when viewed from the side, as shown in Figure 3(b). This arrangement reduces the lateral vibration (vibration in the x-direction) of each transducer 1 compared to the case where the acoustic matching section 4X is trapezoidal when viewed from the side, as in the transducer unit of the comparative example shown in Figure 5, and the gap between them is also trapezoidal. By reducing the lateral vibration of the transducer 1, the accuracy of the ultrasonic image can be improved. This rectangular gap may be filled with a filler. The presence of a filler can increase the mechanical strength of the transducer unit 10. The material of the filler is not particularly limited, but for example, silicone rubber, urethane rubber, and epoxy resin can be used.

[0035] When an acoustic matching section 5 is provided on top of an acoustic matching section 4, it is preferable to make the acoustic impedance of the acoustic matching section 5 smaller than the acoustic impedance of the acoustic matching section 4. That is, it is preferable that the acoustic matching section 4 and the acoustic matching section 5 are made of different materials. By providing the acoustic matching section in layers using multiple materials, the difference in acoustic impedance with the subject 500 can be reduced, and the attenuation of the amplitude of the transmitted and received ultrasonic waves can be suppressed. The materials of the acoustic matching section 4 and the acoustic matching section 5 are not particularly limited, and for example, glass, carbon, and epoxy resin can be used.

[0036] The x-direction length D3 of the acoustic matching sections 4a and 5a is preferably shorter than the x-direction length W1 of the piezoelectric element 3a. Furthermore, the x-direction length D3 of the acoustic matching sections 4a and 5a is longer than the spacing D2 between adjacent acoustic matching sections 4. In addition, the spacing D2 between adjacent acoustic matching sections 4 is preferably 15 μm or more. This is because these conditions enhance the directivity of the ultrasonic waves generated by the piezoelectric element. The sum of the spacing D2 between adjacent acoustic matching sections 4 and the lengths D3 of the acoustic matching sections 4a and 5a is preferably 60 μm or less. This reduces the influence of artifacts caused by the grating globe on the generated ultrasonic image. The thickness H2 of the acoustic matching section 4 and the thickness H3 of the acoustic matching section 5 are preferably integer multiples of one-quarter of the wavelength of the ultrasonic waves generated by the piezoelectric element 3.

[0037] As described above, according to the embodiment, the distance between piezoelectric elements 3a and 3b gradually narrows as it moves away from the acoustic matching unit 4. By adopting this configuration, the volumes of piezoelectric elements 3a and 3b can be increased even though they are separated from each other. Therefore, even if the frequency of the ultrasonic waves emitted by the piezoelectric element 3 becomes high, a sufficient output from the transducer unit can be obtained. Furthermore, by setting the distance D1 between adjacent piezoelectric elements to 10 μm or less, the output of the transducer unit can be made even more sufficient. In addition, by arranging the acoustic matching units with a rectangular gap between them when viewed from the side, each transducer 1 is less likely to vibrate laterally, and a sufficient output from the transducer unit can be obtained.

[0038] [Manufacturing method for vibrator units] A method for manufacturing a vibrator unit according to an embodiment will be explained using Figure 4.

[0039] The processing apparatus 20 includes a light source 21, an optical system (not shown) for focusing laser light 22 emitted from the light source 21, a chamber 24, an incident window 23 for injecting light into the chamber 24, and a stage 25. The light source 21 is a laser light source, and the wavelength of the laser light is 380 nm or less, i.e., ultraviolet light. The light source can be, for example, an excimer laser, a harmonic of an argon ion laser, or the third harmonic of a solid-state laser such as Nd:YAG. In order to make the spacing between piezoelectric elements narrow, it is preferable that the wavelength of the laser light be short and the pulse width be short. Furthermore, the preferred pulse width of the laser light is several ps (picoseconds) to tens of fs (femtoseconds), and more preferably 300 fs or less.

[0040] First, the first component 10A is placed on the stage 25 inside the chamber 24. The first component 10A is a component in which an electrode section 2A, a piezoelectric element section 3A, and an acoustically matching material section 4A are laminated together.

[0041] Next, the pressure inside the chamber is reduced to below atmospheric pressure. Specifically, the chamber is evacuated using an exhaust means such as a scroll pump or rotary pump (not shown). It is preferable to reduce the pressure inside the chamber to 200 Pa or less.

[0042] Subsequently, a laser beam 22 is incident on the acoustic matching material section 4A to form grooves in the first member 10A, thereby forming multiple transducers 1 (see Figures 4(a) and (b)). The multiple transducers are a first transducer 1a having a first piezoelectric element 3a and a first acoustic matching section 4a provided on the first piezoelectric element 3a, and a second transducer 1b having a second piezoelectric element 3b and a second acoustic matching section 4b provided on the second piezoelectric element 3b. By performing the groove formation process in a reduced-pressure environment lowered below atmospheric pressure, the mean free process of the debris (processing waste) generated during processing is lengthened. This makes it easier to discharge the debris out of the grooves and allows for the formation of grooves with a small width, making it possible to narrow the pitch between the first transducer 1a and the second transducer 1b. Narrowing the pitch between the transducers reduces the influence of artifacts caused by the grating globe on the generated ultrasonic image. A more preferable atmosphere is 100 Pa or less.

[0043] It is preferable to use a material with a high sublimation point, such as carbon, for the acoustic matching material section 4A. This allows for the removal of only the laser beam irradiation spot during groove processing. Furthermore, by moving the stage 25 up and down, the focal position in the depth direction can be changed, making it easy to form rectangular grooves. On the other hand, since the piezoelectric ceramics or piezoelectric single crystals used in the piezoelectric element section 3A have a lower melting point than the sublimation point of carbon, the spacing D1 between adjacent piezoelectric elements can be adjusted by controlling the laser power after the formation of the acoustic matching layer 4. Also, by fixing the focal position, the groove can become narrower due to multiple reflections as it goes inward (in the depth direction). Therefore, by fixing the focal position to the piezoelectric element section, it is possible to easily form V-shaped grooves with a high aspect ratio where the spacing between piezoelectric elements is narrow.

[0044] The oscillator unit 10 can be obtained through the above process.

[0045] Furthermore, if the space between the first vibrator 1a and the second vibrator 1b is to be filled with a filler, the vibrator unit 10 can be removed from the chamber 24 after the above process is completed, and then the filler such as silicone rubber can be filled in.

[0046] In previously known techniques, the groove formation process described above was performed using a blade. However, as the ultrasonic frequency required for ultrasonic probes increased, it became necessary to form grooves of narrow width. Blade processing proved extremely difficult for grooves narrower than 20 μm.

[0047] However, according to the embodiment described above, since grooves are formed in the transducer unit 10 using a short-wavelength laser with a wavelength of 380 nm or less, V-shaped grooves with a high aspect ratio, where the spacing between piezoelectric elements 3 narrows as it moves away from the acoustic matching section 4, can be easily formed. Therefore, even if the frequency of the ultrasonic waves emitted by the piezoelectric elements 3 becomes high, sufficient output can be obtained from the transducer unit. Furthermore, by setting the spacing D1 between adjacent piezoelectric elements to 10 μm or less, the output of the transducer unit can be made even more sufficient. In addition, by arranging the acoustic matching sections with a rectangular spacing between them when viewed from the side, each transducer 1 is less likely to vibrate laterally, and sufficient output can be obtained from the transducer unit. [Examples]

[0048] The following will provide examples. First, we will explain the evaluation method for the oscillator unit.

[0049] [Evaluation method for transducer units] Connect the created oscillator unit to the pulse receiver and apply a voltage of 10V. p0By adding the necessary components, a pulsed ultrasonic wave with a center frequency of 20 MHz was generated in the water, and the amplitude of the sound wave on the receiving end was measured as the output value. The pulse receiver used was a JPR-50P and receiving probe manufactured by Japan Probe Co., Ltd. The output value of the transducer unit in the reference example was set to 1, and the ratio of the output values ​​of the examples and comparative examples (output ratio) was calculated. Products with an output ratio greater than 1.4 were classified as A, those between 1.3 and 1.4 as B, those greater than 1 and less than 1.3 as C, and those 1 or less as D. Products A, B, and C were judged to be good products.

[0050] (Example 1-1) The transducer unit was manufactured using the procedure shown in Figure 4. In Example 1-1, when viewed from the side, the first acoustic matching section and the second acoustic matching section are spaced apart by a rectangular space, and the distance D1 between the first piezoelectric element and the second piezoelectric element narrows as it moves away from the first and second acoustic matching sections.

[0051] First, as shown in Figure 4(a), the first component 10A was placed on the stage 25 inside the chamber 24 to manufacture the oscillator unit. The first component 10A is a laminated component consisting of an electrode section 2A, a piezoelectric element section 3A, and an acoustic matching material section 4A. The acoustic matching material section 4A is a flat carbon plate with dimensions of 0.4 cm in width, 1.0 cm in length, and 100 μm in thickness. The piezoelectric element section 3A is a PMN-PT single crystal with gold electrodes on both sides, and the gold electrode on the side not in contact with the acoustic matching material section is the electrode section 2A. The PMN-PT single crystal has dimensions of 0.4 cm in width, 1.0 cm in length, and 100 μm in thickness. The acoustic matching material section 4A and the piezoelectric element section 3 are bonded together with adhesive.

[0052] Next, the pressure inside the chamber was reduced below atmospheric pressure. Specifically, the chamber was evacuated using a rotary pump (not shown) and the pressure was reduced to 100 Pa.

[0053] Next, laser light 22 was emitted from the light source 21, a femtosecond laser CARBIDE manufactured by LIGHT CONVERSION, and irradiated the first component 10A with the laser light 22 through the incident window 23. The pulse width of the laser light was 244 fs (femtoseconds), and the wavelength was 343 nm. The beam diameter of the laser light emitted from the light source was 2.4 mm, and it was expanded 4.8 times by a beam expander S6EXZ5075 / 574 manufactured by Sill Optics (not shown). After that, the beam was focused by a focusing lens UDL-30-100P manufactured by Sigma Koki, and groove machining was started with a spot diameter of 9.7 μm. Grooving was performed while moving the stage 25 up and down to change the focal position.

[0054] After forming the vibrator 1a, the stage 25 was moved, and the first member 10A was moved in the transverse direction of the paper as shown in Figure 4(b) to continue groove processing, thereby creating the vibrator unit of Example 1-1. In the vibrator unit of Example 1-1, the thickness H1 of the piezoelectric elements was 100 μm, and the spacing D1 between the piezoelectric elements was 10 μm. The spacing narrowed as it moved away from the acoustic matching section 4, with the minimum spacing being 2 μm. That is, H1 / D1 was 10. Also, D2 was 20 μm and D3 was 40 μm.

[0055] Next, the transducer unit of Reference Example 1 was manufactured in the same manner as the transducer unit of Example 1-1. However, the transducer unit of Reference Example 1 differs from that of Example 1-1 in the following respects: In the transducer unit of Reference Example 1, the widths of D1 and D2 were equal and 20 μm. Also, the spacing D1 between the piezoelectric elements remained constant even when moving away from the acoustic matching unit 4.

[0056] Next, the output of the transducer units in Example 1-1 and Reference Example 1 was evaluated. The output ratio of the transducer unit in Example 1-1 was 1.45, so it was evaluated as A.

[0057] (Examples 1-2) Example 1-2 was manufactured in the same manner as Example 1-1. In the transducer unit of Example 1-2, the piezoelectric element thickness H1 was 100 μm, and the piezoelectric element spacing D1 was 20 μm. The spacing narrowed as it moved away from the acoustic matching unit 4, with the minimum spacing being 4 μm. That is, H1 / D1 was 5. Also, D2 was 20 μm and D3 was 40 μm. The output ratio of the transducer unit of Example 1-2 was 1.40, so it was evaluated as B.

[0058] (Examples 1-3) Examples 1-3 were manufactured in the same manner as Example 1-1. In the transducer unit of Example 1-3, the piezoelectric element thickness H1 was 100 μm, and the piezoelectric element spacing D1 was 25 μm. The spacing narrowed as it moved away from the acoustic matching unit 4, with the minimum spacing being 5 μm. That is, H1 / D1 was 4. Also, D2 was 30 μm and D3 was 30 μm. The output ratio of the transducer unit of Example 1-3 was 1.35, so it was evaluated as B.

[0059] (Comparative Example 1) The shape of the transducer unit 10X of Comparative Example 1 is shown in Figure 5. The transducer unit 10X has four transducers 1X. Each transducer 1X is provided on a conductive layer 2X. Each transducer 1X also has a piezoelectric element 3X and an acoustic matching section 4X. The transducer unit of Comparative Example 1 differs from Examples 1-1, 1-2 and 1-3 in that the spacing between adjacent acoustic matching sections 4X is trapezoidal rather than rectangular, and the spacing between adjacent piezoelectric elements 3 is rectangular.

[0060] In Comparative Example 1, the transducer unit had a D2 of 20 μm and a D3 of 40 μm. Furthermore, the spacing D1 between the piezoelectric elements remained constant even when moving away from the acoustic matching section 4X.

[0061] Next, the output of the transducer unit of Comparative Example 1 was evaluated. The output ratio of the transducer unit of Comparative Example 1 was 0.92, so the evaluation was D.

[0062] (Example 2-1) In Example 2-1, the distance D1 between the first piezoelectric element and the second piezoelectric element is 10 μm or less, and the distance narrows as it moves away from the first and second acoustic matching sections.

[0063] In Example 2-1, the first member 10A is a laminated member comprising an electrode portion 2A, a piezoelectric element portion 3A, and an acoustically matching material portion 4A, with the PMN-PT single crystal of the piezoelectric element portion 3A having a width of 0.4 cm, a length of 1.0 cm, and a thickness of 50 μm.

[0064] Except for that point, it was manufactured in the same manner as in Example 1-1. In the oscillator unit of Example 2-1, the piezoelectric element thickness H1 was 50 μm, and the spacing between piezoelectric elements D1 was 5 μm. The spacing narrowed as it moved away from the acoustic matching section 4, with the minimum spacing being 1.5 μm. That is, H1 / D1 was 10. Also, D2 was 10 μm and D3 was 20 μm.

[0065] Next, the transducer unit of Reference Example 2 was manufactured in the same manner as the vibration unit of Example 2-1. However, the transducer unit of Reference Example 2 differed from that of Example 2-1 in the following respects: In the transducer unit of Reference Example 2, the widths of D1 and D2 were equal and 10 μm. Also, the spacing D1 between the piezoelectric elements remained constant even when moving away from the acoustic matching unit 4.

[0066] Next, the output of the transducer units in Example 2-1 and Reference Example 2 was evaluated. The output ratio of the transducer unit in Example 2-1 was 1.43, so it was evaluated as A.

[0067] (Example 2-2) Example 2-2 was manufactured using the same method as Example 2-1. In the transducer unit of Example 2-2, the piezoelectric element thickness H1 was 50 μm, and the piezoelectric element spacing D1 was 10 μm. The spacing narrowed as it moved away from the acoustic matching unit 4, with the minimum spacing being 3 μm. That is, H1 / D1 was 5. Also, D2 was 10 μm and D3 was 20 μm. The output ratio of the transducer unit of Example 2-2 was 1.35, so it was evaluated as B.

[0068] (Comparative Example 2) The shape of the transducer unit 10X in Comparative Example 2 is the same as that of Comparative Example 1, as shown in Figure 5.

[0069] In Comparative Example 2, the transducer unit had a D2 of 10 μm and a D3 of 20 μm. Furthermore, the spacing D1 between the piezoelectric elements remained constant even when moving away from the acoustic matching unit 4X.

[0070] Next, the output of the transducer unit of Comparative Example 2 was evaluated. The output ratio of the transducer unit of Comparative Example 2 was 0.91, so the evaluation was D.

[0071] These results are summarized in Tables 1 and 2. [Table 1] [Table 2]

[0072] As shown in Table 1, the force generated by the shape displacement of the piezoelectric element 3 when voltage is applied and when the voltage is removed increases in proportion to the area. Therefore, when the dimensions in the depth direction are the same, it was confirmed that making D1 narrower than D2 improves the output ratio compared to when D1 and D2 are the same. Furthermore, it was confirmed that the output ratio improves by making the spacing between the piezoelectric elements a V-shape, which narrows as it moves away from the acoustic matching section, thereby reducing the volume of piezoelectric material removed.

[0073] Furthermore, as shown in Table 2, it was confirmed that even when the element (transducer) pitch is narrowed, high output can be obtained by making the spacing between piezoelectric elements a V-shape, where the spacing narrows as it moves away from the acoustic matching section. By narrowing the pitch width, it becomes possible to increase the number of elements in the scanning direction of the ultrasonic probe, so it is expected that the output will be further improved. In addition, the generation of grating lobes can be suppressed, so an improvement in the resolution of ultrasonic images can also be expected.

[0074] As described above, according to this disclosure, even though piezoelectric elements 3a and 3b are separated from each other, the volumes of piezoelectric elements 3a and 3b can be increased compared to conventional designs. Therefore, even when the frequency of the ultrasonic waves emitted by piezoelectric element 3 is high, the output of the transducer unit can be sufficiently obtained. Furthermore, by setting the spacing D1 between adjacent piezoelectric elements to 10 μm or less, the output of the transducer unit can be made even more sufficient. In addition, by arranging the acoustic matching sections with a rectangular spacing when viewed from the side, each transducer 1 is less likely to vibrate laterally, and the output of the transducer unit can be sufficiently obtained.

[0075] This embodiment includes the following configurations and methods.

[0076] (Composition 1) A first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element, A vibrator unit comprising a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, the second vibrator being positioned at a distance from the first vibrator, The distance D1 between the first piezoelectric element and the second piezoelectric element is 10 μm or less, and narrows as it moves away from the first and second acoustic matching sections. A vibrator unit characterized by the following features.

[0077] (Configuration 2) The transducer unit according to Configuration 1, wherein, when the transducer unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged with a rectangular gap between them.

[0078] (Composition 3) The oscillator unit according to configuration 1 or 2, wherein the ratio of the height H1 of the first piezoelectric element to D1 is 5 or more.

[0079] (Composition 4) The transducer unit according to any one of configurations 1 to 3, wherein the frequency of the ultrasonic waves generated from the first piezoelectric element and the second piezoelectric element is 30 MHz or higher.

[0080] (Composition 5) The vibrator unit according to any one of configurations 1 to 4, wherein the distance D2 between the first acoustic matching section and the second acoustic matching section is 15 μm or more.

[0081] (Composition 6) The transducer unit according to configuration 5, wherein, when the transducer unit is viewed from the side, the sum of the width D2 and the width D3 of the first acoustic matching section is 60 μm or less.

[0082] (Composition 7) The oscillator unit according to any one of configurations 1 to 6, wherein the first piezoelectric element and the second piezoelectric element include a single-crystal piezoelectric body.

[0083] (Composition 8) The vibrator unit according to any one of configurations 1 to 7, wherein the first acoustic matching section and the second acoustic matching section are made of a plurality of materials.

[0084] (Composition 9) A first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element, A vibrator unit comprising a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, the second vibrator being positioned at a distance from the first vibrator, When the transducer unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged with a rectangular gap between them. The distance D1 between the first piezoelectric element and the second piezoelectric element narrows as it moves away from the first and second acoustic matching sections. A vibrator unit characterized by the following features.

[0085] (Composition 10) The oscillator unit according to configuration 9, wherein the ratio of the height H1 of the first piezoelectric element to D1 is 5 or more.

[0086] (Composition 11) The transducer unit according to configuration 9 or 10, wherein the frequency of the ultrasonic waves generated from the first piezoelectric element and the second piezoelectric element is 30 MHz or higher.

[0087] (Composition 12) The vibrator unit according to any one of configurations 9 to 11, wherein the distance D2 between the first acoustic matching section and the second acoustic matching section is 15 μm or more.

[0088] (Composition 13) The transducer unit according to configuration 12, wherein, when the transducer unit is viewed from the side, the sum of D2 and the width D3 of the first acoustic matching section is 60 μm or less.

[0089] (Composition 14) The oscillator unit according to any one of configurations 9 to 13, wherein the first piezoelectric element and the second piezoelectric element include a single-crystal piezoelectric body.

[0090] (Composition 15) The transducer unit according to any one of the configurations 9 to 14, wherein the first acoustic matching section and the second acoustic matching section are made of a plurality of materials.

[0091] (Composition 16) The casing and The oscillator unit described in any one of the configurations 1 to 15 arranged inside the housing, An ultrasonic probe characterized by having the following features.

[0092] (Composition 17) Configuration 16 includes an ultrasound probe, The apparatus is characterized by having an image generation unit that generates an image based on the reflected wave received by the ultrasonic probe.

[0093] (Method 1) A step of installing a first member having a piezoelectric element and an acoustic matching material provided on the piezoelectric element in a chamber, A step of reducing the pressure inside the chamber to below atmospheric pressure, A step of providing a groove in the first member using laser light with a wavelength of 380 nm or less, a first vibrator having a first piezoelectric element and a first acoustic matching portion provided on the first piezoelectric element, and a second vibrator having a second piezoelectric element and a second acoustic matching portion provided on the second piezoelectric element, and being arranged at a distance from the first vibrator, A method for manufacturing a vibrator unit, characterized by having the following features.

[0094] (Method 2) A method for manufacturing an oscillator unit according to Method 1, wherein the pulse width of the laser light is 300 fs or less.

[0095] (Method 3) A method for manufacturing an oscillator unit according to method 1 or 2, wherein the pressure inside the chamber is 200 Pa or less. [Explanation of symbols]

[0096] 1. Oscillator 2 Conductive part 3. Piezoelectric element 4 Acoustic matching section 5 Acoustic matching section 20 Processing equipment 21 Laser light source 22 Laser light 23 Entrance window 24 chambers 25 stages 10A First component 2A conductive part 3A Piezoelectric element section 4A acoustic matching material 10 transducer units 100 Ultrasound Probes 110 Backing material 120 Acoustic Lens 200 Main body 210 Transmit / Receive Circuit Section 220 Image generation unit 230 Storage section 300 Display 400 Input section 500 subjects 1000 Ultrasound diagnostic equipment (device)

Claims

1. A first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element, A vibrator unit comprising a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, the second vibrator being spaced apart from the first vibrator, When the transducer unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged with a rectangular gap between them. A vibrator unit characterized in that the distance D1 between the first piezoelectric element and the second piezoelectric element is 10 μm or less, and narrows as it moves away from the first acoustic matching section and the second acoustic matching section.

2. A first vibrator having a first piezoelectric element and a first acoustic matching section provided on the first piezoelectric element, A vibrator unit comprising a second piezoelectric element and a second acoustic matching section provided on the second piezoelectric element, the second vibrator being spaced apart from the first vibrator, When the transducer unit is viewed from the side, the first acoustic matching section and the second acoustic matching section are arranged with a rectangular gap between them. A vibrator unit characterized in that the distance D1 between the first piezoelectric element and the second piezoelectric element narrows as it moves away from the first acoustic matching section and the second acoustic matching section.

3. The vibrator unit according to claim 2, wherein the ratio of the height H1 of the first piezoelectric element to the spacing D1 is 5 or more.

4. The transducer unit according to claim 2, wherein the frequency of the ultrasonic waves generated from the first piezoelectric element and the second piezoelectric element is 30 MHz or higher.

5. The transducer unit according to claim 2, wherein the distance D2 between the first acoustic matching section and the second acoustic matching section is 15 μm or more.

6. The transducer unit according to claim 5, wherein, when the transducer unit is viewed from the side, the sum of the spacing D2 and the width D3 of the first acoustic matching section is 60 μm or less.

7. The oscillator unit according to claim 2, wherein the first piezoelectric element and the second piezoelectric element include a single-crystal piezoelectric body.

8. The vibrator unit according to claim 2, wherein the first acoustic matching section and the second acoustic matching section are made of a plurality of materials.

9. The casing and A vibrator unit according to any one of claims 1 to 8, disposed within the housing, An ultrasonic probe characterized by having the following features.

10. Claim 9 describes an ultrasonic probe, The apparatus is characterized by having an image generation unit that generates an image based on the reflected wave received by the ultrasonic probe.

11. A step of installing a first member having a piezoelectric element and an acoustic matching material provided on the piezoelectric element in a chamber, A step of reducing the pressure inside the chamber to below atmospheric pressure, A step of providing a groove in the first member using laser light with a wavelength of 380 nm or less, a first vibrator having a first piezoelectric element and a first acoustic matching portion provided on the first piezoelectric element, and a second vibrator having a second piezoelectric element and a second acoustic matching portion provided on the second piezoelectric element, and being arranged at a distance from the first vibrator, A step of obtaining the vibrator unit according to claim 2, via the step of providing the second vibrator, A method for manufacturing a vibrator unit, characterized by having the following features.

12. The method for manufacturing an oscillator unit according to claim 11, wherein the pulse width of the laser light is 300 fs or less.

13. The method for manufacturing a vibrator unit according to claim 11, wherein the pressure inside the chamber is 200 Pa or less.

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