JPS6089199A - Array type ultrasonic wave probe - Google Patents

Abstract

PURPOSE:To prevent crosstalk, to improve the mechanical strength and to attain a structure immune to moisture by packing a hollow body to air gap part between elements. CONSTITUTION:Hollow glass balls 22 are packed in the air gap 12 between ultrasonic wave vibrating elements 2. Moreover, an adhesives such as epoxy group is dropped so as to be impregnated into the gaps of the balls 22 and cured. Thus, the air-glass-adhesives boundary having a large ultrasonic wave reflectance is formed between the elements 2, the crosstalk is decreased, the mechanical strength is improved and migration is prevented because the structure is immune to moisture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technique of the Invention 1 (Field i)] The present invention relates to an array-type ultrasonic probe that has improved mechanical strength and reduced crosstalk between each element.

[Komyo's technical back pressure and other problems] In recent years, ultrasound diagnostic methods have come to be widely used in the medical field. For example, a diagnostic method has been proposed in which ultrasonic pulses are emitted into the body from the body surface and acoustic information inside the body is used for diagnosis. Compared to X-ray equipment, this kind of ultrasonic diagnostic equipment can detect biological soft tissues without using contrast agents.
Clinical diagnostic equipment has become popular in the medical field due to the fact that it can be imaged easily, has no radiation damage, is easy to handle, and has improved image quality due to recent advances in ultrasonic pulse 4Ti. However, since most of these conventional ultrasonic diagnostic devices transmit and receive ultrasonic pulses from the surface of the body, it is difficult to diagnose organs deep from the body surface. Disadvantages include the inability to perform high-frequency ultrasound diagnosis with poor resolution, the presence of bone and gas in some areas that cannot be diagnosed, and the influence of subcutaneous fat, which varies greatly from person to person.
Ultrasonic diagnosis from within the body cavity became necessary, and intrabody cavity ultrasound diagnostic devices that housed an ultrasound probe that transmits and receives ultrasound waves in a tubular container that can be inserted into the body cavity have been commercialized. Ta.

Ultrasonic probes that transmit and receive the above-mentioned ultrasonic waves by contacting the body surface from outside the body cavity do not need to be so miniaturized, but if they are used by being inserted into the body cavity through the esophagus etc., a small size is required. is required.

FIG. 1 shows the structure of a conventional array-type ultrasonic probe used inside a body cavity, and FIG. 2 shows a side sectional view of FIG. 1.

That is, in the conventional array-type ultrasonic probe 1, a piezoelectric element plate made of PZT or the like, which can be separated in the thickness direction of the plate, is cut into thin pieces with a narrow width from a temporary vertical direction. Slightly spaced apart J: Array-type piezoelectric elements aligned in a horizontal direction 2. ..., 2 are formed. Electrodes 3a and 3b are formed on both sides of each piezoelectric element 2 in the thickness direction by vapor deposition of silver, etc., and one side on which ultrasonic waves are transmitted and received is
The 138th surface is used as a ground side electrode, and each electrode 3a is maintained conductive by a plate-shaped and conductive flexible substrate 4. Further, first and second electrodes 3a having the same shape as each piezoelectric element 2 and elongated are formed on the flexible substrate 4. The second acoustic matching layers 5 and 6 are bonded together to form a laminated structure.

An acoustic lens 7 whose longitudinal center of each piezoelectric element 2 is convex is formed on the upper surface of the second matching layer 6 .

On the other hand, the surface of the positive electrode 3b of each piezoelectric element 2 has a damping portion (layer) 9 interposed with an insulating layer 8 made of an insulating material.
Each ultrasonic transducer element is formed by being fixed to the ultrasonic transducer element.

The positive electrode 3b is led out to the back side of the damping part 9 from both sides in the longitudinal direction by flexible leads 10b, and the ground side electrode 3a is also led out to the back side by flexible leads 10a.

In the gaps on both sides of the insulating layer 8, the insulating layer 8 is fixed to the damping layer 9 using an adhesive 11 such as an epoxy adhesive.

The first and second matching layers 5 and 6 reduce the reflection of ultrasonic waves transmitted and received from the piezoelectric element 2 on the inner wall of the body cavity, etc., which the front surface (upper surface) of the acoustic lens 7 comes into contact with. ) The acoustic impedance of the piezoelectric element 2 and the inner wall of the body cavity is set to an intermediate value so that the acoustic impedance can be efficiently transmitted to the inner wall of the body cavity.
By using two matching layers 5 and 6, more accurate matching can be achieved.

In the damping layer 9, each piezoelectric element 2 has both electrodes 3a,
When excited by the high-frequency pulse applied to 3b and sending out ultrasonic waves, the ultrasonic waves sent to the back surface (ljll) are immediately tamped, and the waves reflected on the back surface of the tamped moon 9 are received and resolved. This damping layer 9 can be thickened to have a sufficient damping function when used outside the body cavity, but when used inside the body cavity. In some cases, it is the bulkiest member, so a thinner one is required.

In this case, as the material for the tamping m9, it is almost satisfactory to use a material in which tungsten powder is dispersed in epoxy, silicone, 1M vinyl resin, etc. so that the tungsten powder is dispersed in a ratio of approximately 95%. This is so that the amount of attenuation that can be achieved can be achieved.

In the case of the damping strip 9 made of the above material, its electrical resistance is low, so for safety measures against the human body, the ultrasonic wave transmitting and receiving surface side is set to the earth potential side, and the damping layer 9 side is set to the positive electrode side, so that the damping layer 9 If it comes into direct contact with the positive electrode side, the low resistance (impedance) of the member forming the damping layer 9 causes the inconvenience that the ultrasonic transducers divided into an array become electrically conductive.
It is insulated by the insulating layer 8.

By the way, in each ultrasonic transducer, a gap is formed between each adjacent double layer 1 in order to prevent cross-over between the piezoelectric elements 1 and 2. The first
By forming the void portion 12 across three layers including the second matching layer 5.6, crosstalk can be more reliably prevented.

Note that the ultrasonic transducers separated by the gap 12 are, for example, insulated fi! A piezoelectric element plate with electrodes formed on both sides fixed to the piezoelectric element plate 8 is integrated with first and second matching layer plates extending over the piezoelectric element plate, and a part of the insulating layer 8 is cut with a diamond cutter. In this manner, the positive electrode antistatic 9% 3b is cut to form separate sections. In this case, the flexible substrate 4 is held so as to be in contact with each ground electrode 3a after being cut.

In the conventional example configured in this way, the gap 12 is formed between the adjacent piezoelectric elements 2.2 including the matching layer 5.6.
Since the signals are separated by , crosstalk is sufficiently prevented. However, since each element is arranged in an elongated state with a thin width and the elongated side parts are not held, it has a drawback that it is mechanically very weak.

In addition, moisture penetrates into the cavity 12 due to moisture, etc., and the moisture remains in the cavity 12 for a long time, causing migration of the silver of the electrodes 3a and 3b applied to both sides of each pressure-N element 2.
There was a risk that the function of transmitting and receiving ultrasonic waves would deteriorate, or in even worse cases, the system would fall into a state where the ultrasonic waves would go out of order.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and makes it possible to prevent crosstalk between adjacent elements, and
It is an object of the present invention to provide an array type ultrasonic probe that maintains mechanical strength and does not absorb moisture.

[Summary of the Invention] The present invention prevents crosstalk, increases blood mechanical strength, and prevents moisture from entering by filling the gaps between each element with a hollow body.

[Embodiments of the invention] below. The present invention will be specifically described with reference to the drawings.

Figures 3 and 4 relate to one embodiment of the present invention, with Figure 3 showing a cross section of the structure seen from a direction perpendicular to the direction in which the ultrasound beam is scanned, and Figure 4 showing a partially enlarged view. Shown.

In the array type ultrasonic probe 2'1 of the first embodiment, hollow glass spheres 22 are filled in each cavity 12 formed in the same manner as in the conventional example described above.

The hollow crow sphere 22 has a wall thickness of 1 to 2 [mm], a maximum diameter of about 40 [circumferences], and an average density of, for example, 0.37 [g, '塡]. If the hollow glass sphere 22 is used for backing, the clearance ratio of the sphere will be about 35%.

After filling voids 12 having a width of, for example, 50 mm with such hollow glass spheres 22, each void 12 is filled with a viscosity of 5.
00[CI]S] drop by drop from a syringe needle, permeate into the gap between each hollow glass sphere 22, harden at room temperature, and fix each hollow glass sphere 22. Each hollow crow sphere 22 facing
is fixed to the side surface, and a composite material 71 of glass-air-adhesive is formed in the gap between the adjacent elm plates 1. This composite matrix moon contains a considerable amount of air, so that the spaces between adjacent nilemens are nearly enough to be substantially filled with air. At the same time, sufficient mechanical strength is maintained by the filled and fixed hollow glass spheres 22,
Moreover, the hollow glass sphere 22 and adhesive prevent moisture from entering.

The rest of the structure is the same as that of the conventional example described above, and the same members are given the same reference numerals.

According to one embodiment configured in this way, hollow glass spheres 22 are filled in the gaps 12 between the respective ultrasonic transducer elements, and further, an adhesive such as epoxy is infiltrated into the gaps between the hollow glass spheres. By dripping it onto the glass and curing it, an air-glass-adhesive interface with high ultrasonic reflectance is formed between each element, so the cloth can be made small, and it has high mechanical strength and is resistant to moisture. Migration can be prevented because it does not enter.

In the above-mentioned embodiment, a hollow crow sphere was used as the hollow structure member to be filled into the cavity 12, but the present invention is not limited to this, but a porous member may also be used, and heat treatment or laser treatment may be used. It also includes a hollow member in which holes are formed using light or the like.

In addition, in the above embodiment, the matching layer is 2rv1, but
The present invention applies not only to the case of 2 or more, but also to the case of 30 or more and 1B.
This also includes the case of Moreover, a structure in which the proportion of the composition is continuously varied and the 'tS\1 impedance of the matching layer is continuously varied belongs to the present invention.

In the above embodiment, after forming the separation gap 12,
The flexible substrate 4 can be interposed to establish electrical conduction with the ground electrode 3a of each piezoelectric element 2. J: This is a sea urchin, but the flexible substrate 4 is bonded to the ground electrode surface with a part of its longitudinal direction protruding, and further aligned. If the layers 5 and 6 are also glued and integrated and then cut to form the gap 12, the invention also applies to a structure in which the ground side of each element can be electrically connected in common at the protruding portion of the flexible substrate 4. It is something that succumbs to.

[Effects of the Invention] As described above, according to the present invention, the voids separating the ultrasonic transducer elements arranged in an array can be formed so as to be filled with hollow members such as hollow glass bulbs. Therefore, crosstalk is sufficiently prevented especially in the hollow part, the mechanical strength of the packed parts is increased, and the adhesive is used to prevent moisture from entering between the packed parts to prevent migration. It can be prevented.

[Brief explanation of the drawings] Figures 1 and 2 relate to conventional examples, Figure 1 is a sectional view showing a conventional array type ultrasound probe, and Figure 2 is a cross-sectional view taken in a direction perpendicular to Figure 1. 3 and 4, which are partially enlarged side sectional views showing the inside of the circle, relate to one embodiment of the present invention, and FIG.
FIG. 4 is an enlarged sectional view showing a part of FIG. 3, which is a side sectional view of the embodiment. 2... Piezoelectric element 3a, 3b... Electrode 4... Flexible substrate 5, 6... Matching layer 7... Acoustic lens 8... Insulating solid 9... Damping part (layer) 10a, 10b... Flexible lead 11... Adhesive 12... Cavity 21... Ultrasonic probe 22... Hollow glass sphere Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 22 3b

Claims (1)

[Claims] (1) An acoustic matching layer is formed on one surface of the pressure-N element that transmits and receives ultrasonic waves, and a damping section is formed on the other surface of each ultrasonic transducer element adjacent to each other. [Array ff' formed by providing a cavity between cymen 1 and array ff' [In a sonic probe, an array type characterized by having a structure in which the cavity is filled with hollow members (14 pieces) Ultrasonic probe. (2) A patent claim characterized in that the hollow structure member is a hollow glass sphere, and is bonded to each other with an epoxy adhesive or the like and fixed to the side wall of the element. The array type ultrasonic probe according to the range i Jr+.