Ultrasonic probe

Abstract

To provide an ultrasonic probe having stable acoustic performance.SOLUTION: An ultrasonic probe arranges a plurality of piezoelectric elements on a backing material (1) along an azimuth direction. The backing material (1) has a front surface where the plurality of piezoelectric elements are arranged, a rear surface facing opposite the front surface, a pair of first side surfaces extending in the azimuth direction, and a pair of second side surfaces extending in an elevation direction, and is provided with a cover member (4) covering at least the rear surface of the backing material (1) and the pair of first side surfaces. The cover member (4) is formed with a material higher in Young's modulus than the backing material (1) and heat conductivity, and adhered to the backing material (1) not via an adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ultrasound probe used for capturing ultrasound images. [Background technology]

[0002] In the medical field, ultrasonic diagnostic devices for capturing ultrasonic images have been put to practical use for some time. Generally, this type of ultrasonic diagnostic device transmits ultrasonic beams from an ultrasonic probe toward the inside of a subject, receives ultrasonic echoes from the subject with the ultrasonic probe, and generates an ultrasonic image by electrically processing the received signals.

[0003] Such ultrasonic probes often have a configuration in which a plurality of piezoelectric elements, acoustic matching layers, etc. are laminated on a backing material, as disclosed in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-142171 Summary of the Invention [Problem to be solved by the invention]

[0005] When stacking multiple piezoelectric elements and acoustic matching layers on a backing material, the multiple piezoelectric elements and acoustic matching layers may be bonded to the backing material while applying pressure. During this pressure bonding, the backing material may be deformed. If the backing material is deformed, the piezoelectric elements and acoustic matching layers may also be deformed or tilted, resulting in a deterioration in the acoustic performance of the ultrasonic probe compared to the design values.

[0006] The present invention has been made to solve such conventional problems, and has as its object to provide an ultrasonic probe having stable acoustic performance. [Means for solving the problem]

[0007] The above object can be achieved by the following configuration. [1] An ultrasonic probe in which a plurality of piezoelectric elements are arranged in an array along the azimuth direction on the front surface of a backing material, the backing material has a front surface on which the plurality of piezoelectric elements are arranged, a rear surface facing in the opposite direction to the front surface, a pair of first side surfaces extending along an azimuth direction, and a pair of second side surfaces extending along an elevation direction; a cover member that covers at least the rear surface and the pair of first side surfaces of the backing material and supports the backing material; The cover member is made of a material having a Young's modulus and a thermal conductivity higher than those of the backing material, and is in close contact with the backing material without an adhesive layer therebetween. [2] The ultrasonic probe according to [1], wherein the cover member covers the rear surface, the pair of first side surfaces, and the pair of second side surfaces of the backing material. [3] The ultrasonic probe according to [1] or [2], wherein the cover member is made of a metal material. [4] A flexible circuit board is provided on the front surface of the backing material; The ultrasonic probe according to any one of [1] to [3], wherein the plurality of piezoelectric elements are arranged on the surface of a flexible circuit board. [5] The flexible circuit board has at least one wiring layer including a plurality of wirings and a plurality of grooves formed corresponding to the spaces between the plurality of piezoelectric elements; a filler is filled between the plurality of piezoelectric elements and in the plurality of grooves of the flexible circuit board; The ultrasonic probe according to [4], wherein the plurality of grooves in the flexible circuit board are spaced apart from the plurality of wirings. [Effects of the Invention]

[0008] The present invention is an ultrasonic probe in which a plurality of piezoelectric elements are arranged in an array along the azimuth direction on the front surface of a backing material, the backing material having a front surface on which the plurality of piezoelectric elements are arranged, a rear surface facing the opposite direction to the front surface, a pair of first side surfaces extending along the azimuth direction, and a pair of second side surfaces extending along the elevation direction, the ultrasonic probe having a cover member that covers at least the rear surface and the pair of first side surfaces of the backing material and supports the backing material, the cover member being formed from a material having a higher Young's modulus and thermal conductivity than the backing material and being in close contact with the backing material without an adhesive layer therebetween, thereby enabling the ultrasonic probe to have stable acoustic performance. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of an ultrasound probe according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a backing material according to the first embodiment of the present invention. [Figure 3] 3A and 3B are views showing a cover member according to the first embodiment of the present invention. [Figure 4] 2 is a diagram showing a cover member and a backing material according to the first embodiment of the present invention. FIG. [Figure 5] 5A and 5B are diagrams showing another example of the cover member in the first embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the configuration of an ultrasound probe according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing a plurality of grooves according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following description of the components will be given based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the terms "same" and "identical" include a margin of error generally accepted in the technical field.

[0011] Embodiment 1 The configuration of an ultrasonic probe according to a first embodiment of the present invention is shown in Figure 1. Figure 1 shows a cross section of the ultrasonic probe extending along a so-called elevation direction D1. The ultrasonic probe includes a backing material 1, a piezoelectric layer 2 laminated on the backing material 1, an acoustic matching layer 3 laminated on the piezoelectric layer 2, and a cover member 4 that covers the backing material 1.

[0012] The piezoelectric layer 2 has a piezoelectric portion 2A, a first electrode layer 2B formed on the surface of the piezoelectric portion 2A facing the acoustic matching layer 3, and a second electrode layer 2C formed on the surface of the piezoelectric portion 2A facing the backing material 1. The piezoelectric layer 2 is divided into a plurality of parts in the so-called azimuth direction perpendicular to the elevation direction D1, and these multiple parts form a plurality of piezoelectric elements arranged in an array. When a voltage is applied to the multiple piezoelectric elements, the multiple piezoelectric elements expand and contract in the stacking direction, emitting ultrasonic waves.

[0013] The piezoelectric body 2A is made of a known piezoelectric material, such as piezoelectric ceramics such as PZT (lead zirconate titanate) or polymer materials such as PVDF (polyvinylidene fluoride).

[0014] The acoustic matching layer 3 is intended to match the acoustic impedance between the piezoelectric body 2A and the subject with which the ultrasonic probe comes into contact during use, thereby facilitating the incidence of ultrasonic waves into the subject. The acoustic matching layer 3 can be made of a material whose acoustic impedance is smaller than that of the piezoelectric body 2A and larger than that of the subject.

[0015] The backing material 1 supports the piezoelectric layer 2 and the acoustic matching layer 3. As shown in Fig. 2, the backing material 1 has a rectangular parallelepiped shape having a front surface 1A on which a plurality of piezoelectric elements are arranged, a rear surface 1B facing in the opposite direction to the front surface 1A, a pair of first side surfaces 1C extending along the azimuth direction D2, and a pair of second side surfaces 1E extending along the elevation direction D1.

[0016] The backing material 1 is composed of a base material and a filler dispersed in the base material. The base material may be, for example, a rubber material, an epoxy resin material, or a polyurethane resin material. The filler may be, for example, ferrite, tungsten, or manganese.

[0017] As shown in Fig. 3, the cover member 4 has a recess R having a bottom surface 4B, a pair of first inner wall surfaces 4C extending along the azimuth direction D2, and a pair of second inner wall surfaces 4E extending along the elevation direction D1. By accommodating the backing material 1 in the recess R, the cover member 4 covers the rear surface 1B, a pair of first side surfaces 1C, and a pair of second side surfaces 1E of the backing material 1 as shown in Fig. 4, and supports the backing material 1. In addition, the cover member 4 is in close contact with the backing material 1 without an adhesive layer therebetween.

[0018] For example, when forming the backing material 1 by hardening a liquid material, the liquid material of the backing material 1 is poured into the recess R of the cover member 4, and the liquid material is hardened in that state to form the backing material 1, thereby allowing the cover member 4 to adhere to the backing material 1 without an adhesive layer.

[0019] Generally, when the piezoelectric layer 2, the acoustic matching layer 3, etc. are laminated on the backing material 1, the piezoelectric layer 2, the acoustic matching layer 3, etc. are sometimes adhered to the backing material 1 while applying pressure. If there is no cover member 4 covering the backing material 1, the backing material 1 may deform during this pressure adhesion. If the backing material 1 deforms, the piezoelectric layer 2, the acoustic matching layer 3, etc. may also deform or tilt, which may result in the acoustic performance of the ultrasonic probe being worse than the design value.

[0020] In the present invention, the cover member 4 covers the rear surface 1B, the pair of first side surfaces 1C, and the pair of second side surfaces 1E of the backing material 1 and adheres closely to the backing material 1 without an adhesive layer, thereby preventing deformation of the backing material 1 even when the piezoelectric layer 2 and the acoustic matching layer 3 are pressure-bonded to the backing material 1. In particular, if there is a gap between the backing material 1 and the cover member 4, the pressure-bonding may cause the backing material 1 to deform toward the gap. However, since the cover member 4 in the first embodiment adheres closely to the backing material 1 without any gaps, even very small deformations are suppressed. Therefore, the acoustic performance of the ultrasonic probe does not change during the manufacturing process, and the acoustic performance can be stable.

[0021] Furthermore, the cover member 4 is made of a material with a higher Young's modulus than the backing material 1. This allows the backing material 1 to be firmly supported when the piezoelectric layer 2 and the acoustic matching layer 3 are pressure-bonded to the backing material 1, improving the effect of preventing deformation of the backing material 1.

[0022] Furthermore, the cover member 4 is made of a material with a higher thermal conductivity than the backing material 1. It is generally known that a piezoelectric element generates heat when a voltage is applied to the piezoelectric element to emit ultrasound waves from the piezoelectric element, and when the piezoelectric element receives ultrasound echoes from the subject and generates an electrical signal. The heat generated by the piezoelectric element in this way can be released to the outside via the backing material 1, but by forming the cover member 4 from a material with a higher thermal conductivity than the backing material 1, more heat can be released to the outside.

[0023] The cover member 4 can be made of a material having a higher Young's modulus and thermal conductivity than the backing material 1, for example, a metal material such as aluminum, copper, or stainless steel.

[0024] As described above, according to the ultrasonic probe of the first embodiment, the cover member 4 covers the rear surface 1B, the pair of first side surfaces 1C, and the pair of second side surfaces 1E of the backing material 1 and adheres closely to the backing material 1 without an adhesive layer, preventing deformation of the backing material 1 even when the plurality of piezoelectric elements and the acoustic matching layer 3 are pressure-bonded to the backing material 1, thereby enabling the ultrasonic probe to have stable acoustic performance. Furthermore, the cover member 4 that adheres closely to the backing material 1 allows heat generated in the plurality of piezoelectric elements to be effectively released to the outside.

[0025] Although the cover member 4 has been described as covering the rear surface 1B, the pair of first side surfaces 1C, and the pair of second side surfaces 1E of the backing material 1, it may alternatively be configured to cover at least the rear surface 1B and the pair of first side surfaces 1C of the backing material 1, but not the front surface 1A or the pair of second side surfaces 1E, as shown in Fig. 5, for example. Even in this case, it is possible to prevent deformation of the backing material 1 due to pressure bonding of the multiple piezoelectric elements and the acoustic matching layer 3 to the backing material 1. However, deformation of the backing material 1 can be more effectively prevented if the cover member 4 also covers the pair of second side surfaces 1E.

[0026] Embodiment 2 The ultrasonic probe may also include a flexible circuit board between the backing material 1 and the piezoelectric layer 2, which is electrically connected to the piezoelectric layer 2.

[0027] Fig. 6 shows the configuration of an ultrasonic probe according to embodiment 2. The ultrasonic probe according to embodiment 2 includes a flexible circuit board 5 between the backing material 1 and the piezoelectric layer 2 in the ultrasonic probe according to embodiment 1 shown in Fig. 1.

[0028] The piezoelectric layer 2 is divided into a plurality of portions in the azimuth direction D2 to form a plurality of piezoelectric elements. At this time, the continuous piezoelectric portion 2A, first electrode layer 2B, and second electrode layer 2C connected in the azimuth direction D2 are cut with a so-called dicing blade, and a plurality of grooves G are formed to separate the plurality of piezoelectric elements E, as shown in Fig. 7. The plurality of grooves G are filled with a filler F to mechanically reinforce the plurality of piezoelectric elements E.

[0029] The flexible circuit board 5 also has a plurality of electrode pads P in contact with and electrically connected to the second electrode layer 2C of the plurality of piezoelectric elements E, a first wiring layer 11 including a plurality of wires 11A, and a second wiring layer 12 including a plurality of wires 12A and positioned deeper than the first wiring layer 11. The plurality of electrode pads P and the plurality of wires 11A and 12A are electrically connected via through holes T formed in the flexible circuit board 5. The plurality of grooves G are spaced apart from the wires 11A of the first wiring layer 11 and the wires 12A of the second wiring layer 12. In the example of FIG. 7 , the positions of the grooves G do not overlap with the wires 11A of the first wiring layer 11, and the grooves G have a cutting depth that is deeper than the first wiring layer 11 and shallower than the second wiring layer 12. Although not shown, when the ultrasonic probe is viewed from the stacking direction of each layer, if the position of the dicing blade when forming the groove G overlaps the position of the wiring 11A of the first wiring layer 11, the groove G has a cutting depth shallower than that of the first wiring layer 11 so as to be separated from the wiring 11A.

[0030] Here, for example, if the ultrasonic probe does not include a cover member 4 and the backing material 1 is deformed by pressure bonding of the piezoelectric layer 2 and the acoustic matching layer 3 to the backing material 1, the flexible circuit board 5 arranged on the backing material 1 may also be deformed together with the backing material 1. In this case, when an attempt is made to cut the piezoelectric body portion 2A, the first electrode layer 2B, and the second electrode layer 2C, the dicing blade may come into contact with the multiple wirings 11A and 12A in the flexible circuit board 5, causing disconnection of the multiple wirings 11A and 12A.

[0031] According to the ultrasonic probe of the second embodiment, the cover member 4 tightly covers the rear surface 1B, the pair of first side surfaces 1C, and the pair of second side surfaces 1E of the backing material 1, thereby preventing deformation of the backing material 1 and the flexible circuit board 5. Therefore, as shown in Fig. 7, when the piezoelectric body portion 2A, the first electrode layer 2B, and the second electrode layer 2C are cut according to a predetermined design, the dicing blade is prevented from coming into contact with the plurality of wirings 11A and 12A in the flexible circuit board 5, and disconnection of the plurality of wirings 11A and 12A during the manufacturing process can be prevented.

[0032] 7 shows that the flexible circuit board 5 includes two wiring layers, a first wiring layer 11 and a second wiring layer 12, but the flexible circuit board 5 may include at least one wiring layer. When the flexible circuit board 5 has two or more wiring layers, the wiring structure of the flexible circuit board 5 becomes complex, but since the cover member 4 prevents deformation of the backing material 1 and the flexible circuit board 5, according to the present invention, breakage of the multiple wires 11A and 12A during the manufacturing process can be prevented.

[0033] Furthermore, the ultrasonic probe may be, for example, a so-called one-dimensional probe, a so-called 1.5-dimensional probe, or a so-called two-dimensional probe. In particular, when the ultrasonic probe is a 1.5-dimensional probe or a two-dimensional probe, the number of piezoelectric elements is large and the wiring structure of the flexible circuit board 5 electrically connected to the plurality of piezoelectric elements becomes complex. However, since the cover member 4 prevents deformation of the backing material 1 and the flexible circuit board 5, according to the present invention, breakage of the plurality of wirings 11A and 12A during the manufacturing process can be prevented. [Explanation of symbols]

[0034] 1 backing material, 1A front surface, 1B rear surface, 1C first side surface, 1E second side surface, 2 piezoelectric layer, 2A piezoelectric portion, 2B first electrode layer, 2C second electrode layer, 3 acoustic matching layer, 4 cover member, 4B bottom surface, 4C first inner wall surface, 4E second inner wall surface, 5 flexible circuit board, 11 first wiring layer, 11A, 12A wiring, 12 second wiring layer, E piezoelectric element, G groove, F filler, D1 elevation direction, D2 azimuth direction, P electrode pad, R recess, T through hole.

Claims

1. An ultrasonic probe in which a plurality of piezoelectric elements are arranged in an array along an azimuth direction on the front surface of a backing material, the backing material has a front surface on which the plurality of piezoelectric elements are arranged, a rear surface facing in the opposite direction to the front surface, a pair of first side surfaces extending along an azimuth direction, and a pair of second side surfaces extending along an elevation direction; a cover member that covers at least the rear surface and the pair of first side surfaces of the backing material and supports the backing material; The cover member is made of a material having a Young's modulus and a thermal conductivity higher than those of the backing material, and is in close contact with the backing material without an adhesive layer therebetween.

2. The ultrasonic probe according to claim 1 , wherein the cover member covers the rear surface, the pair of first side surfaces, and the pair of second side surfaces of the backing material.

3. The ultrasonic probe according to claim 1 , wherein the cover member is made of a metal material.

4. a flexible circuit board disposed on the front surface of the backing material; 4. The ultrasonic probe according to claim 1, wherein the plurality of piezoelectric elements are arranged on a surface of the flexible circuit board.

5. the flexible circuit board has at least one wiring layer including a plurality of wirings and a plurality of grooves formed corresponding to the spaces between the plurality of piezoelectric elements; a filler is filled between the plurality of piezoelectric elements and in the plurality of grooves of the flexible circuit board; The ultrasonic probe according to claim 4 , wherein the plurality of grooves of the flexible circuit board are spaced apart from the plurality of wirings.

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