JPH0591594A - Ultrasonic transducer - Google Patents

Abstract

PURPOSE:To provide the good and compact ultrasonic transducer. CONSTITUTION:In a ultrasonic transducer 2, a vibrator 11 with an electrode 12 on the emission side and an electrode 13 on the rear side is provided on a case 10, an acoustic matching layer 14 is provided on the emission front side of the vibrator 11, an acoustic absorption layer 15 is provided at the rear of the vibrator 11, thus transmitting an electric signal from the electrodes 12 and 13 to a cable 16. A conduction member 20 is provided in the case 10, and the electric signal from the electrode 12 on the emission front side can be transferred through the conduction member 20 to the cable 16. At least one part of the case 10 is made of the conductive metal, and the electric signal from the electrode 12 on the emission front side is transferred through the case 10 to the cable 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a case with a vibrator having a radiation side electrode and a back side electrode, and an acoustic matching layer (also referred to as a matching layer) on the radiation side of the vibrator.
The present invention relates to an ultrasonic transducer having a structure in which an acoustic absorption layer (also referred to as a backing layer) is provided on the back side of the vibrator and electric signals from the radiation surface side electrode and the back surface side electrode are transmitted to a cable.

[0002]

2. Description of the Related Art Ultrasonic transducers are used as probes for medical diagnostic equipment, metal flaw detectors for nondestructive inspection, etc., and are also called ultrasonic probes, ultrasonic probe heads, ultrasonic probes, etc. is there.

The ultrasonic transducers can be morphologically classified into a single probe and an array probe, and the array probe can be further subdivided into a linear array, an annular array, a two-dimensional array and the like. In addition, as a special one mainly used in the medical field, a mechanical probe that mechanically scans a single probe (usually called a mechsec probe) or a probe for a catheter that is inserted into a body cavity by being incorporated in an endoscope or the like. However, these are in the stage of being commercialized now.

The operation of the ultrasonic transducer will be briefly described. An electric pulse sent from the apparatus main body is converted into an ultrasonic pulse, which is radiated toward a subject and an ultrasonic pulse reflected from the subject is converted into an ultrasonic pulse. It is detected and converted into an electrical signal.

The basic configuration of the ultrasonic transducer will be described. The ultrasonic transducer has a case, and a transducer, a backing layer, a matching layer, and a cable (in general, a shielded cable is used, so a thing composed of a signal line and a ground line is called a cable) is provided in the case. Has been. A vibrator is an element that converts electric signals and ultrasonic waves, and is usually used for both transmission and reception. Electrodes are formed on both sides of the vibrator, and the electrodes are electrically connected to the main body of the device via lead wires and cables. A backing layer (backside damping layer) is formed on the back surface of the vibrator, and a matching layer (matching layer) is formed on the opposite radiation surface. An acoustic lens may be attached to the matching layer to focus the ultrasonic waves. A ceramic piezoelectric material (body) is generally used as the oscillator material, but a polymer piezoelectric material (body) such as PVDF or a composite piezoelectric material (body) obtained by combining the two is also used.

The electrodes on both sides of the vibrator are connected to a signal line and a ground line (both are collectively referred to as a lead line). Since the back side electrode faces one lead wire and is close to the same person, the shortest path can be connected by the lead wire. However, since the vibrator is located between the electrode on the opposite radiation surface side and the other lead wire, the lead wire cannot be directly connected. For this reason, conventionally, a wrap-around electrode is connected to the radiation surface side electrode, the wrap-around electrode is pulled out to the back side, and a lead wire is connected thereto.

[0007]

However, it takes a lot of time and effort to form the rolled-in electrode, resulting in a high manufacturing cost. Also in terms of quality, because of taking out the two lead wires (signal wire and ground wire) from the back side,
Ultrasonic transducer miniaturization and various characteristics (directivity,
There is a limit to improvement in sensitivity and the like, and it is difficult to manufacture a transducer for high frequency. Further, from the viewpoint of improving withstand voltage and reliability, the short insulation distance due to the spirally wound electrode is an obstacle. In addition, the use of the swirl electrode causes a problem that the effective area of the back electrode is reduced.

An object of the present invention is to solve the above problems of the prior art and to provide a high-quality ultrasonic transducer which can be reduced in diameter and size.

[0009]

According to a first aspect of the present invention, a vibrator having a radiation surface side electrode and a back surface side electrode is provided in a case, and an acoustic matching layer is provided on the radiation surface side of the transducer. In an ultrasonic transducer having a structure in which an acoustic absorption layer is provided on the back side and electric signals from the radiation surface side electrode and the back surface side electrode are transmitted to a cable, a conductive member 20 is provided inside the case 10, and the radiation surface is provided. The gist of the ultrasonic transducer is that an electric signal from the side electrode 12 is transmitted to the lead wire 18 via the conductive member 20.

According to the second aspect of the present invention, a vibrator having an emission surface side electrode and a back surface side electrode is provided in a case, an acoustic matching layer is provided on the emission surface side of the vibrator, and an acoustic absorption layer is provided on the back surface side of the oscillator. In the ultrasonic transducer configured to transmit electric signals from the radiation surface side electrode and the back surface side electrode to a cable, at least a part of the case (110) is made of a conductive metal, and the radiation surface is formed. Side electrode (11
The gist of the ultrasonic transducer is that an electric signal from 2) is transmitted to a cable (116) via the case (110).

[0011]

In the first aspect of the present invention, since the conductive member is provided inside the case and the electric signal from the radiation surface side electrode is transmitted to the cable through the conductive member, the space can be saved and the size can be reduced. In addition, since it passes through the conductive member, the insulation distance becomes long and the withstand voltage property and reliability are improved. In addition, it is possible to increase the effective area of the back side electrode and improve the sensitivity. Further, since the work of connecting the cable and the radiation surface side electrode becomes easy, the manufacturing cost can be reduced.

In the second aspect of the present invention, at least a part of the case is made of a conductive metal, and the electric signal from the radiation surface side electrode is transmitted to the cable through the case. Is almost the same as the operation of the first invention.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a mechanical sector scanner 1 equipped with an ultrasonic transducer 2 according to the present invention. FIG. 2 is a sectional view conceptually showing the ultrasonic transducer 2 according to the present invention.

The mechanical sector scanner 1 is a system in which a transducer 2 and a drive unit are provided at the tip portion to mechanically swing the transducer, and the transducer 2 is not directly attached to the tip portion, but rather the tip portion (conceptually Is used together with the drive unit in the outer case).

A vibrator 11 is fixed to the top of the case 10. The oscillator 11 is a piezoelectric material, for example, a relative dielectric constant ε /
It is made of a PZT-based piezoelectric material having ε _o of 2000 and a coupling coefficient K _t of 50%. The vibrator 11 is for 5 MHz and has a dimension and shape of 20 mm in outer diameter and 0.4 mm in thickness.

Electrodes 12 and 13 are formed on the sound wave emitting surface side and the back surface side of the vibrator 11, respectively. Electrode 12,
Reference numeral 13 is a vibrator 11 coated with silver paste on both sides and baked, and its thickness is set to, for example, 10 μm. The outer diameter of the radiation side electrode is set to 20 mm, and the outer diameter of the back side electrode is set to 17 mm.

An acoustic matching layer 14 is provided on the radiation surface side of the vibrator 11.
(Matching layer) is provided. The acoustic matching layer 14 is made of, for example, an epoxy resin containing a filler material and has an outer diameter of 22 m.
m and the thickness is set to 0.2 mm.

An acoustic absorption layer 15 (backing layer) is provided on the back side of the vibrator. The material of the acoustic absorption layer 15 is, for example, a soft epoxy resin containing a filler material.

As shown in FIG. 3, the case 10 has a cylindrical shape as a whole, and has an outer diameter of 22 mm and an inner diameter of 19 mm. A recess 21 for holding the vibrator is provided on the top of the case 10. The recess 21 has a diameter of 20 mm and a depth of 0.3 mm. A wire 20 having a diameter of 0.5 mm as a conductive member is embedded in the side wall of the case 10. The wire 20 is 10.5 mm from the central axis of the case 10.
It is located in the position. A groove 22 for installing a lead wire is provided on the bottom of the case 10. The groove 22 is the case 10
It has a substantially rectangular cross-section extending from the inner diameter portion toward the outer circumference, and has a radial length of 2.3 mm, a height of 1 mm, and a circumferential width of 0.5 mm. The top end of the wire 20 is flush with the top end face of the case 10, and the bottom back end is flush with the top face of the groove 22.

Referring again to FIG. 2, a cable 16 is installed on the back of the case 10, and the tip of the cable 16 is located inside the acoustic absorption layer 15. The cable 16 has a shield function, and the lead wire 1 on the signal side is used.
7 is connected to the back side electrode. On the other hand, the ground-side lead wire passes through the groove 22 and is connected to the end of the wire 20 on the back side. The top end of the wire 20 and the radiation surface side electrode are connected by a conductive adhesive, for example, an adhesive containing silver particles. Further, the bottom back side end of the wire 20 and the lead wire 18 are similarly connected using a conductive adhesive.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a sectional view conceptually showing an ultrasonic transducer according to the present invention. The ultrasonic transducer has a metal case 110 (for example, made of brass) for holding a vibrator. The case 110 has a cylindrical shape as a whole, but may be formed in a polygonal prism shape.

A vibrator 111 is fixed to the top of the case 110. The vibrator 111 is a piezoelectric material, for example, P having a relative permittivity ε / ε _o = 2000 and a coupling coefficient K _t = 50%.
A ZT-based piezoelectric material is used. This oscillator 111 is 5M
For Hz, dimensions and shape are 10 mm outer diameter and 0.4 m thickness
m. Electrodes 112 and 113 are formed on the ultrasonic wave emitting surface side and the back surface side of the vibrator 111, respectively. The electrodes 112 and 113 are formed by applying a silver paste on both sides of the vibrator 111 and baking it, and the thickness thereof is set to, for example, 10 μm. The diameter of the radiation surface side electrode 112 is 10 mm,
The diameter of the back electrode 113 is set to 8 mm. Further, the vibrator 111 is polarized so that the ultrasonic wave emitting surface is on the ground side.

A matching layer 114 is provided on the radiation surface side of the vibrator 111. The matching layer 114 is made of, for example, an epoxy resin containing a filler material and has an outer diameter of 12 m.
m and the thickness is set to 0.2 mm. A backing layer 115 is provided on the back side of the vibrator 111. The material of the backing layer 115 is, for example, a soft epoxy resin containing a filler material.

As shown in FIG. 5, the case 110 has a cylindrical shape, and its dimensions are, for example, an outer diameter of 12 mm and an inner diameter of 9 mm.
mm and length can be set to 10 mm. A resonator holding recess 121 is provided on the top of the case 110. Recess 12
1 has a diameter of 10 mm and a depth of 0.2 mm. The radiation surface side electrode 112 is electrically connected to the case 110 by, for example, a conductive adhesive containing silver particles. Similarly, the ground side lead wire 118 is also electrically connected to the case 110 by a conductive adhesive. That is, the ultrasonic wave emitting surface side electrode 112 and the ground side lead wire 118 are connected with the case 1 as an electrically conducting path.

A cable 116 is installed on the back of the case 110, and the tip of the cable 116 has a backing layer 1.
Located within 15. A cable having a shield function is used as the cable 116, and the lead wire 117 on the signal side is connected to the back electrode 113 by a conductive adhesive containing silver particles, for example. At this time, if a conductive material (for example, tungsten powder) is used as the filler material of the backing layer 115, the insulation resistance between the lead wires is lowered. Therefore, here, the insulating material (for example, zirconia powder, alumina powder) is used as the filler material. ) Is used.

FIG. 6 is a perspective view showing a case used in still another embodiment of the present invention. In this case 210, the surface portion other than the electrical contact portions 221 and 222 of the radiation surface side electrode and the case 210, and the ground side lead wire and the case 210 are anodized with a thickness of 10 μm. The electrical contact portion 221 may be, for example, the recess 22.
0.3 mm outward from the outer periphery of 0, width 1 mm
It is formed over. The electrical joint portion 222 is
It is formed on the inner surface of the case with a shape of 1 mm from a position 2 mm from the bottom and a width of 1 mm in the figure. Further, the diameter of the back electrode is 10 mm. Other structures and configurations of the ultrasonic probe are in accordance with the embodiment shown in FIG.

In the examples shown in FIGS. 5 and 6, an acoustic lens was attached to the matching layer so that the distance of 40 mm was the maximum sensitivity point, and the sensitivity in water was measured. As a result, the sensitivity at the maximum sensitivity point was -41.3 dB in the example of FIG. 5 and -39.2 dB in the example of FIG. For comparison, a similar experiment was performed in the conventional example of the shunt electrode system, and a value of -42.5 dB was obtained.

By using the case shown in FIG. 6, the ultrasonic transducer itself is completely insulated from the outside, and effects such as noise reduction and safety improvement can be obtained. Furthermore, since the back-side electrode can be formed with the same diameter as the outer shape of the vibrator, the effective area of the back-side electrode can be maximized and the sensitivity characteristics can be further improved.

[0029]

According to the first aspect of the present invention, a vibrator having a radiation surface side electrode and a back surface side electrode is provided in a case, an acoustic matching layer is provided on the radiation surface side of the transducer, and acoustic absorption is provided on the back surface side of the transducer. An ultrasonic transducer having a layer for transmitting electric signals from the radiation surface side electrode and the back surface side electrode to a cable, a conductive member 20 is provided inside the case 10, and the radiation member from the radiation surface side electrode 12 is provided. Since the ultrasonic transducer 2 is characterized in that an electric signal is transmitted to the cable 16 via the conductive member 20, it is necessary to form a twisted electrode to connect the radiation side electrode and the cable. Absent. Therefore, since only one lead wire is taken out from the back side of the vibrator, it is possible to manufacture a small diameter, high frequency ultrasonic transducer.

Further, in the case of the same shape, the insulation distance becomes longer than that in the case where the spirally wound electrode is formed, and the withstand voltage property,
The reliability can be improved.

Further, in the same shape, the electrode diameter (effective area) on the back side as compared with the case where the spirally wound electrode is formed.
Can be increased and the sensitivity characteristics can be improved.

Further, since the labor for forming the twisted electrodes can be omitted, the cost can be reduced.

In the second aspect of the present invention, at least a part of the case is made of a conductive metal, and the signal from the radiation surface side electrode is transmitted to the cable through the case. Obtainable. Further, in the second invention, since an electrode similar to the outer shape of the vibrator can be formed, it is expected that the directional characteristic as well as the sensitivity characteristic can be improved.

The present invention is not limited to the above embodiment. For example, the conductive member may be a flat member instead of the wire. Further, SUS or the like may be used as the material of the case. Furthermore, an insulating material may be baked or coated as an insulating treatment of the case.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mechanical scanner equipped with an ultrasonic transducer according to the present invention.

FIG. 2 is a sectional view conceptually showing an ultrasonic transducer according to the present invention.

FIG. 3 is a perspective view showing a case in the ultrasonic transducer of the present invention.

FIG. 4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a sectional view conceptually showing another embodiment of the present invention.

FIG. 6 is a sectional view showing a case of still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Mechanical scanner 2,102 Ultrasonic transducer part 10,110,210 Case 11,111 Transducer 12,112 Radiation side electrode 13,113 Back side electrode 14,114 Acoustic matching layer 15,115 Acoustic absorption layer 16,116 Cable 17 , 18, 117, 118 Lead wire 19, 119 Conductive adhesive 20 Wire 21, 220 Recess 22 Groove ◆

Claims (2)

[Claims] 1. A vibrator having a radiation surface side electrode and a back surface side electrode is provided in a case, an acoustic matching layer is provided on the radiation surface side of the transducer, and an acoustic absorption layer is provided on the back surface side of the transducer. In an ultrasonic transducer configured to transmit an electric signal from a radiation surface side electrode and the back surface side electrode to a cable, a conductive member (20) is provided inside the case (10), and the radiation surface side electrode (12) is The ultrasonic transducer for transmitting the electric signal of 1) to the cable (16) via the conductive member (20). 2. A vibrator having a radiation surface side electrode and a back surface side electrode is provided in a case, an acoustic matching layer is provided on the radiation surface side of the transducer, and an acoustic absorption layer is provided on the back surface side of the transducer. In an ultrasonic transducer configured to transmit electric signals from a radiation surface side electrode and the back surface side electrode to a cable, at least a part of the case (110) is made of a conductive metal, and the radiation surface side electrode (112) is formed. ) From the cable (11) via the case (110).
6) An ultrasonic transducer characterized by transmitting to (6).