JPS5817358A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To eliminate damage and peeling of machining layers by employing a soft adhesive for the bonding of a first matching layer with a piezo-electric vibrator in an ultrasonic probe having more than one sound maching layers. CONSTITUTION:A piezo-electric vibrator 23 in which silver electrodes 22 and 24 are mounted on the top and bottom surfaces thereof is bonded on a packing material 20, a first matching layer 26 with a thickness of lambda/4 bonded on the top surface thereof with a soft adhesive and a second matching layer 28 with a thickness of lambda/4 bonded on the surface thereof with an adhesive 27 to form an ultrasonic probe. An electric signal is inputted from signal drawing wires 30 and 31 while ultrasonic waves are radiated from the second matching layer in contact with an object 2 to be inspected. As the hardness of the adhesive lowers, the trailing time thereof reduces thereby indicating a better ultrasonic wave reflection characteristic. Where an adhesive is applied on the electrode surface of the piezo-electric vibrator and the surface of the first matching layer and hardened in an electric furnace or the like, the use of a soft adhesive allows ample absorption of difference in the thermal expansion coefficient of material between the piezo-electric vibrator and the first matching layer thereby making the matching layers hard to damage and peel.

Description

DETAILED DESCRIPTION OF THE INVENTION Jin's invention relates to an ultrasonic probe, and particularly to an ultrasonic probe having two or more acoustic matching layers.

Conventionally, an ultrasonic probe has a piezoelectric transducer 3, as shown in FIG. The structure has an acoustic matching layer 5 on the ultrasonic radiation surface.This acoustic matching layer may have a two-layer structure or a structure with seven or more layers, as shown in Figure 1 (blK). In practical use, there are many 1Fi two-layer structures on the market that have one layer.
Ru. For example, a so-called medical ultrasound probe is used to inject ultrasound into the human body and obtain information about the body from the reflected waves.
``c butterfly, the acoustic impedance of the piezoelectric vibrator is 32J
10'kg/B"set The acoustic impedance of the human body is 1.5 x lo@47"@ec, so in an ultrasound probe with a two-layer matching layer structure, the acoustic impedance of the al l matching layer is 15. OX 10'JIl)/@'s
ec, the acoustic impedance of the second matching layer is 3.23
xo”#i/♂sec (l1if”
on 8&U Yoj8U-26, No6. Noy
, 1979J, H, Gold pass~393). As a result, for example, the first matching layer is made of quartz glass, Kame 2
The matching layer is made of MMA resin. In this case, it is common to use a high-impedance bonding agent to bond the piezoelectric vibrator and the first matching layer, or these adhesives may be bonded due to differences in thermal expansion due to temperature changes. The matching layer is prone to breakage or peeling, which is one of the causes of a decline in the manufacturing yield of ultrasonic probes.

In addition, since these adhesives (1 layer degree is still <1 layer degree) and Q are large φ, Km adhesive between the transducers gets mixed in, and vibrations are transmitted to the adjacent transducers on both sides, causing unnecessary vibrations. Adverse effects such as ultrasonic waves being emitted from areas larger than the required area occurred.

The present invention has been made in view of the above points, and an object of the present invention is to provide an ultrasonic probe in which an acoustic matching layer and a piezoelectric vibrator are bonded together using a soft adhesive. This invention uses a soft adhesive to bond the first matching layer and the piezoelectric vibrator in an ultrasonic probe having two or more acoustic matching layers, thereby preventing damage or peeling off of the matching layer.
In addition, acoustic coupling due to adhesive protrusion etc. is eliminated,
This makes it possible to manufacture probes with effective characteristics.

Hereinafter, the present invention will be explained in detail with reference to the drawings. Second
The figure shows an embodiment of the present invention, in which a piezoelectric vibrator 23 with silver electrodes 22 and 24 attached to the upper and lower surfaces is glued onto the backing material 20, and a λ/4 This ultrasonic probe has a structure in which a first matching layer 26 having a thickness is adhered with a soft adhesive 25, and a JR2 matching layer 28 having a thickness of λ/4 is adhered to the upper surface thereof with an adhesive 27. The electrical signal is inputted from the signal extraction 4930.31, and the ultrasonic wave is emitted from the #I2 matching layer in contact with the object to be inspected 29. FIG. 3 shows the relationship between the hardness of the adhesive used to bond the piezoelectric vibrator and the first matching layer shown in FIG. As shown in the same figure, it can be seen that as the hardness of the adhesive decreases, the trailing time does not become shorter and the ultrasonic reflection characteristics become longer. In addition, when bonding the first matching layer to the piezoelectric vibrator, apply adhesive to the electrode surface of the piezoelectric vibrator and the surface of the first matching layer, and place the adhesive in an electric furnace or the like to harden it. Since the materials of the first matching layer have different thermal expansion coefficients, a hard adhesive cannot absorb this difference in thermal expansion coefficient, and the matching layer is likely to break or flake. When such a soft adhesive is used, this difference in coefficient of thermal expansion can be sufficiently absorbed, and damage to the matching layer and flaking 9 are less likely to occur. Furthermore, when this ultrasonic probe has an array structure, if this adhesive penetrates between the piezoelectric transducers, if this adhesive is hard, it will become an acoustic propagator. However, if this adhesive is soft as in the present invention, it will absorb the vibrations and cause the vibrations to deteriorate. No acoustic coupling is provided.

As explained above, according to the present invention, damage to the matching layer and flaking 9 can be prevented, and the performance and reliability of the ultrasonic probe can be improved.

Figure 2 is a cross-sectional diagram showing an embodiment of the present invention, and Figure 3 is a cross-sectional diagram showing the tailing characteristics of the ultrasonic probe according to the present invention and the hardness of the adhesive. FIG.

20...Backing material 22.24...Silver electrode 23...Piezoelectric vibrator 26.28...Acoustic matching layer 25... Soft adhesive 27...Adhesive Figure 1 Ji 31

Claims (1)

[Claims] In an ultrasonic probe in which one surface of a piezoelectric vibrator having electrode tubes formed on opposing upper and lower surfaces is adhered to a backing material, and two or more acoustic matching layers are configured on the other surface, the piezoelectric An ultrasonic probe characterized in that a vibrator is bonded to a layer of the multilayer acoustic matching layer closest to the piezoelectric vibrator using a soft adhesive.