JPH04102398U - ultrasound probe - Google Patents

Abstract

(57) [Summary] [Structure] A plurality of grooves 7 having a rectangular cross section are formed in the vibrator substrate 3 made of a piezoelectric element such that the bottom surface of the groove is parallel to the surface of the vibrator substrate 3 facing the groove. Provided parallel to each other. An acoustic absorbing material 2 is provided on the vibrator substrate 3 so as to cover each of the grooves 7 . The surface of the vibrator substrate 3 facing the bottom surface is polished to provide a vibrator 8 between the bottom surface and the surface of the vibrator substrate 3 facing thereto. [Effect] A vibrator 8 with a thinner thickness than the conventional one can be stably obtained. Therefore, it is possible to generate ultrasonic waves with a higher frequency than before.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention is used, for example, in an ultrasound imaging apparatus, which is a medical imaging apparatus. This invention relates to an ultrasonic probe that generates high-frequency sound waves.

0002

[Conventional technology]

Conventionally, the ultrasonic printer used in linear electronic scanning type ultrasonic imaging equipment For example, as shown in FIG. An ultrasonic probe using a rectangular plate-shaped transducer 21 made of a material such as It is being In such an ultrasonic probe, the plurality of transducers 21... They are arranged in an array on the absorbing material 22, and an acoustic match is placed on the acoustic radiation surface of each vibrator 21. an acoustic lens 24 and the like are arranged on it, and the ultrasonic probe For example, if the operating frequency of the vibrator is 3MHz, each vibrator 21 with a thickness of 0.5 mm is arranged. They are lined up. The molding process of each vibrator 21 in such an ultrasonic probe is , First, a polarized PZT thin plate (thickness 0.5 mm) is glued onto the acoustic absorbing material 22. Next, this PZT thin plate is cut into pieces by sequentially cutting grooves 25 with a diamond cutter. By performing these operations sequentially and in parallel at predetermined intervals, approximately 200 of the above-mentioned Each of the rectangular plate-shaped vibrators 21 is formed as shown in FIG.

0003

[Problem that the idea aims to solve]

In recent years, the frequencies used have been further increased to improve the resolution ability of ultrasound imaging equipment. To increase the frequency, for example 30MHz, ceramic materials such as PZT are required. The thickness of the vibrator 21 consisting of There is a point. However, it is difficult to process a PZT thin plate of such thickness as described above. It is difficult. In other words, the PZT thin plate mentioned above is thinner than the 0.5mm currently used. In this case, the PZT thin plate made of ceramic is likely to be damaged in the process of forming the groove 25. Therefore, it is difficult to obtain an ultrasonic probe with high resolution. This is causing problems.

0004

[Means to solve the problem]

The ultrasonic probe of the present invention has a groove provided on a transducer substrate made of a piezoelectric element, An acoustic absorbing material covering this groove is provided on the vibrator substrate and facing the bottom of the groove. The surface of the vibrator substrate is polished so that the bottom of the groove and the vibrator substrate facing thereto are polished. It is characterized by being provided as a vibrator between the surface and the surface.

[0005]

[Effect]

According to the above configuration, electricity is transmitted between the bottom of the groove and the surface of the vibrator board opposite to it. If applied, the space between them can be vibrated as a vibrator, and the Since the acoustic absorbing material is provided, ultrasonic waves are emitted from the transducer substrate surface. I can shoot. In addition, each groove is formed on the vibrator substrate, and then the grooves are formed on the vibrator substrate. If the entire opposing surface of the bottom of the groove is polished to reduce the thickness of the vibrator substrate, it will be possible to Since there is no large force applied when dividing the transducer board, there is no chance of damage to the transducer board. The shape is such that a vibrator with a thinner thickness than before can be stably obtained. did Therefore, an ultrasonic probe with such a shape can transmit higher frequency ultrasonic waves than conventional ones. may occur.

[0006]

【Example】

An embodiment of the present invention will be explained based on FIGS. 1 to 5 as follows. It is. As shown in FIG. 3. An acoustic matching material 4 and an acoustic lens 5 are sequentially laminated. substrate For 1, a material is selected and used that has a predetermined strength and is easy to bond with the acoustic absorbing material 2. The acoustic absorbing material 2 has a material that does not interfere with the ultrasonic waves emitted from one side of the piezoelectric element 3. What about an elastic body that can absorb ultrasonic vibrations emitted from other surfaces? For example, rubber may be used. The acoustic matching material 4 is Acoustic lens 5 with low rigidity is used to transmit ultrasonic waves efficiently during interviews. In order to generate a good signal, the acoustic impedance is significantly different from that of the highly rigid PZT element 3. Therefore, a material with an acoustic impedance and sound speed intermediate between these two is selected. is selected, and combines both of them with less loss. Furthermore, acoustic matching material 4 is a multilayer structure with sequentially varying acoustic impedance to reduce transmission loss. You can also use it as The acoustic lens 5 directs the ultrasonic waves generated by the vibrations in a predetermined direction. In order to emit light efficiently, the shape is usually shaped like a semi-cylindrical shell with a curved front. In addition, since it is used in contact with a living body, it has an acoustic impedance similar to that of a living body. A material with sonic speed is selected.

[0007] The piezoelectric element 3 is made of lead zirconate titanate based ceramic material in consideration of piezoelectric sensitivity, etc. A mix is used (hereinafter, the piezoelectric element 3 will be referred to as a PZT element 3). This P The ZT element 3 is molded through the manufacturing process described below. First, as shown in Figure 3 After the lead zirconate titanate ceramic powder is pressure molded, it is sintered to e.g. It is molded into a dense piezoelectric ceramic plate 11 with a length of 100 mm, a width of 10 mm, and a thickness of 1 mm. electroless nickel plating (approximately 1 micron thick). Next, high voltage (20KV/cm) is applied to both surfaces to polarize. Subsequently, the polarized piezoelectric ceramic plate 1 As shown in Figure 4, on one side of 1, there is a roughly rectangular cross section with a length of 8 mm, a width of 0.3 mm, and a depth of 0.9 mm. The bottom surface of the shaped groove 7 is parallel to the surface of the piezoelectric ceramic plate 11 facing this bottom surface. to form. Such grooves 7 are formed in multiples of 2, such as 256, and are mutually connected. It is formed by grinding in parallel at predetermined intervals using ultrasonic processing. After this, the piezoelectric sensor The entire flat surface of the Lamix board 11 where the grooves 7 are not formed is polished. , the thickness of the piezoelectric ceramic plate 11 is set to 0.95 mm. This polished surface will be explained later. The ultrasonic radiation surface 9 is as shown in FIG. Next, the thinner piezoelectric ceramic Electroless nickel plating (approximately 1 micron thick) is applied to both sides of the base plate 11 again. Furthermore, copper plating (approximately 1 micron thick) is applied to form plated layers. So After that, as shown in FIG. 5, a shape is formed between each groove 7 in the piezoelectric ceramic plate 11. The plating layer on each land portion 13 surface and the plating layer on the ultrasonic radiation surface 9 The first plating layer 14 on the wall surface of each groove 7 and the bottom of each groove 7 are removed by polishing. A second plating layer 15 on the ultrasonic radiation surface 9 facing the surface, and these second plating layers 1 5... is formed with a third plating layer 17 that connects the ultrasonic radiation surface 9 at one end in the width direction. do. Next, select which of the walls on both sides of the bottom of each plated groove 7... Connect the lead wires 16 with solder to each of the first plating layers 14 on either side. On the other hand, a lead is formed on one end surface in the length direction of the third plating layer 17 with solder in the same manner as above. Connect the cable 16. In this way, the vibration of length 8mm, width 0.3mm, thickness 0.05mm A PZT element 3 having a large number of children 8, each of which can be controlled individually, is obtained. This way As shown in FIG. It is placed facing the acoustic absorbing material 2 and used as an ultrasonic probe. In addition, the above The thickness of the transducer 8 depends on the frequency of the ultrasonic wave used. The resonant frequency can be changed depending on the density.

[0008] In such an ultrasonic probe, the first plating layer 14 in each transducer 8... and the second plating layer 15 through each lead wire 16, 16 and the third plating layer 17. Use by applying alternating current according to the frequency used. At this time, the vibrator 8 vibrates. The ultrasonic waves emitted from the ultrasonic radiation surface 9 on the second plating layer 15 side are acoustic It is transmitted to the acoustic lens 5 through the matching material 4, and the surface of this acoustic lens 5 is It comes into contact with the body and is emitted into the living body in a predetermined beam shape. Note that the first plating layer 14 Ultrasonic waves emitted from the sides are absorbed by the acoustic absorbing material 2 and do not leak to the outside.

[0009] By the way, conventionally, when obtaining a vibrator with the thickness mentioned above, a vibrator with a thickness of 0.05 mm is used. The transducer substrate is cut with a diamond cutter, etc., and during the cutting process, the transducer substrate is cut into pieces. Since it is thin, it is easily damaged, making it impossible to stably obtain a thin vibrator as described above. death However, with the shape of the PZT element 3 as described above, the final thickness of the vibrator 8 is The entire ultrasonic radiation surface 9 on which the grooves 7 are not formed in the PZT element 3 is polished. Since it is obtained by polishing, a large force is not applied to the PZT element 3 during molding as in the conventional method. Therefore, each vibrator 8 with a small thickness can be stably obtained.

0010 When such a PZT element 3 is used in the above-mentioned ultrasonic probe, the thickness of the transducer Since it can be made thinner more stably and reliably than before, it has a resolution that can generate higher frequencies. Excellent ultrasonic probes can be manufactured with high precision. In addition, in the above method, ultrasonic Since we use a thinner vibrator, we can easily obtain a thinner vibrator. The child 8 is supported by the thick PZT element 3 that is supported from both sides. Therefore, even if the vibrator 8 is thin, its mechanical strength is maintained. In addition, this Therefore, damage to the PZT element 3 during the installation work is also reduced. Also , the soldering to the PZT element 3 is done on the thick part of the PZT element 3, that is, the 8 parts of the vibrator. Since soldering is performed on parts other than the parts, each vibrator 8 may be destroyed due to thermal shock. Due to heat, piezoelectric performance (at temperatures above 200°C, the oriented crystal state due to polarization is lost) (becomes a random state) will never disappear. Also, high Ultrasonic probes that can generate ultrasonic waves at high frequencies are used, for example, in obstetrics and gynecology to monitor the state of the uterus. and linear electronic scanning medical equipment used in ophthalmology to diagnose intraocular lesions. On the other hand, it non-destructively inspects scratches in the components of machines, etc. It is used in ultrasonic flaw detection equipment, etc.

[0011]

[Effect of the idea]

The ultrasonic probe of the present invention has a groove provided on a transducer substrate made of a piezoelectric element, An acoustic absorbing material covering this groove is provided on the vibrator substrate and facing the bottom of the groove. The surface of the vibrator substrate is polished so that the bottom of the groove and the vibrator substrate facing thereto are polished. This is a configuration in which a vibrator is provided between the surface and the surface. Therefore, each groove is formed on the vibrator substrate, and then the bottom of the groove on the vibrator substrate is formed. If the thickness of the above-mentioned vibrator substrate is reduced by polishing the entire opposing surface, vibration will be reduced as before. Since there is no large force applied when dividing the daughter board, the transducer board may be damaged. This shape allows stable resonators that are thinner than conventional ones. Therefore Therefore, ultrasonic probes with this shape can emit ultrasonic waves at higher frequencies than conventional ones. It has become a viable option. As a result, it has the excellent property of high resolution. It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of an ultrasonic probe according to the present invention.

FIG. 2 is a perspective view of essential parts of the ultrasonic probe.

FIG. 3 is a partial perspective view of a piezoelectric ceramic plate that is a raw material in the ultrasonic probe.

FIG. 4 is a partial perspective view of the piezoelectric ceramic plate in which grooves are formed.

FIG. 5 is a sectional view of a main part of the piezoelectric ceramic plate in which lead wires are soldered to each plating layer.

FIG. 6 is a perspective view of the main parts of a conventional ultrasound probe, with the top removed in a stepwise manner, showing the structure of the ultrasound probe.

[Explanation of symbols]

2 Sound absorbing material 3 PZT element (vibrator board) 7 Groove 8 Oscillator

Claims (1)

[Scope of utility model registration request] 1. A groove is provided on a vibrator substrate made of a piezoelectric element, an acoustic absorbing material covering the groove is provided on the vibrator substrate, and a surface of the vibrator substrate facing the bottom of the groove is polished. An ultrasonic probe characterized in that a vibrator is provided between the bottom of the groove and the surface of the vibrator substrate facing thereto.