JPS595952A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To enhance the reliability of an ultrasonic probe, by providing a first sound matching layer having grooves each of which has a depth reaching the intermediate part of a plate thickness formed thereto at every vibrator group to the front surface of each vibrator group to reduce irregularity in sensitivity. CONSTITUTION:A vibrator 1 comprising piezo-electric elements provided so as to leave predetermined intervals by cut grooves 6 is constituted. A first sound matching layer 7 is constituted from a material such as borosilicate glass and grooves 8 are provided to boundaries at every vibrator groups comprising four vibrators 1 connected in parallel by input and output signal lead wires 5. The depth of each groove 8 is determined in such a size that the vibration of adjacent matching layers is transmitted and a S/N ratio or directionality is not lowered. A second sound matching layer 9 comprising synthetic resin is provided to the front surface of the matching layer 7 and an electrode 10 is provided to the back surface thereof. Because the depth of the groove 8 reaches the intermediate part of the plate thickness, there is no anxiety with respect to the cutting of the vibrator and said vibrator is indivisually prepared while the irregularity in the sensitivity of each vibrator is extremely low and the vibrator small in size and high in reliability is obtained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an ultrasonic probe that transmits and receives ultrasonic waves.

The configuration of a conventional example and its problems will be shown with reference to FIGS. 3 and 4. (1) is a vibrator, which has electrodes (2) and (3) on the front and back surfaces, and is made of a piezoelectric element, such as a piezoelectric ceramic. This vibrator (1) is glued onto a load material (4) such as rubber, and a plurality of vibrators are lined up in a row with cut grooves (6) at predetermined intervals to form a group, thereby forming a plurality of vibrator groups. ing. The electrode (3) on the back side has an input/output signal lead wire (
5) is connected, and a common lead wire Oz for grounding is separately connected to the electrode (2) on the front side across all the vibrators. A first acoustic matching layer (13) is provided in front of the vibrator (1).
are fixed with adhesive, and cutting grooves +14] are provided corresponding to the cutting grooves (6) provided for each vibrator group of the vibrator (1). Usually, there are many structures in which several vibrators are grouped together as a group as shown in Fig. 3, and driven simultaneously by one input/output signal lead wire (5), and in this case, the first acoustic matching layer (13) is also provided with cutting grooves (141) for every several groups of transducers.Also, each transducer (1) has a structure that allows it to be driven independently by connecting one input/output signal lead wire to it. In this case, the cutting groove (141) is also provided for each transducer.A second acoustic matching layer (15) is further provided in front of the first acoustic matching layer (13). .

In the above structure, cutting grooves (6) and (14)
] is generally used to prevent vibrations from being transmitted to adjacent vibrators and the first acoustic matching layer, thereby deteriorating the 8/N ratio and directivity. However, when cutting the first acoustic matching layer for each transducer group as shown in Figure 3, a plate-shaped piezoelectric element is pasted onto the load material and the stiffness is removed using the cutting grooves (6).
After cutting to form the vibrator (1), the first acoustic matching layer (13) must be bonded together, the stiffness must be cut, and the cutting grooves α must be provided. In this case, if the cutting position of the first acoustic matching layer ([3) is shifted, the vibrator (1) will also be cut, and the width of the vibrator (1) will be reduced, resulting in a decrease in sensitivity.

The width of the cutting groove (6) on the transducer is usually extremely narrow, approximately 35 to 110 μm, so it is extremely difficult and requires precision work to provide the cutting groove without cutting the transducer (1). The mass production of tentacles was a major obstacle.

On the other hand, in the case of a structure in which the first acoustic matching layer (13) is cut for each vibrator, the piezoelectric element plate is laminated onto the load material (4), and then the first acoustic matching layer (131) is cut into pieces. pasting,
Thereafter, it is possible to simultaneously cut the first acoustic matching layer and the pressed element plate to obtain the vibrator (1), the cutting groove (6), and the cutting groove circle at the same time.However, in this case, the individual vibrator (1) and the first acoustic matching layer (
The bonding area of I3) was extremely narrow, and therefore the bonding strength was extremely weak, causing the problem that the first acoustic matching layer was more fragile than the vibrator.

Furthermore, the electrode (2+) of the vibrator (1) is connected to the cutting groove (6) and (
Since they are separated from each other by 14I, a grounding common lead Q2+ must be separately provided on the electrode (2) and connected to each other, as shown in FIG. In this case, the first acoustic matching layer (13) cannot be provided on the ground common ground (02), so the radiated ultrasonic waves have a directional characteristic with poor symmetry as shown in (b). However, there is one drawback, such as poor ultrasonic image quality.

OBJECTS OF THE INVENTION An object of the present invention is to provide an ultrasonic probe that is easy to manufacture, has excellent directivity, has small variations in sensitivity, is compact, and has high reliability.

Structure of the Invention The present invention consists of a vibrator consisting of a piezoelectric element with electrodes provided on the front and back surfaces, which is adhesively fixed on a load bearing surface, and cutting grooves are provided at predetermined intervals to form a large number of vibrators. The transducers were grouped together to form a plurality of transducer groups. Lead wires for input/output signals were provided to the electrodes of each group. A first acoustic matching layer made of a borosilicate glass plate or the like is provided on the front surface of the transducer group, and has grooves formed halfway through the thickness of the plate for each transducer group. A second acoustic matching layer was provided in front of the acoustic matching layer. A common ground electrode was provided on the back side of the first acoustic matching layer.

DESCRIPTION OF EMBODIMENTS FIGS. 1 and 2 show examples of the present invention, in which (υ is a vibrator made of a piezoelectric element, (Q, + (31 is an electrode provided on the front and back surfaces of the vibrator, and (4) is a vibrator made of a piezoelectric element. The load material (5) made of rubber etc. is a lead wire for input/output signals, which is made of a flat printed circuit board.The lead wire (5) for input/output signals is attached to the back electrode ( After 31t were joined,
It is adhesively fixed onto the load material (4) using epoxy resin or the like. This piezoelectric element is usually ground and cut with a stone or the like at predetermined intervals of about 02 to Q, 5 wtn, and vibrators (1) are formed by cutting grooves (6) at predetermined intervals.

The cutting groove (6) usually has a width of about 35 to 1.10 μm and a depth that reaches the load material (4). In Fig. 1, the input/output signal lead wires (5) are 4 as one group.
Although it is connected to the electrode (3) of each vibrator, one input/output signal lead wire may be connected to each vibrator (one for each vibrator), or one for each several vibrators. (7) is the first acoustic matching layer, which is made of a material such as borosilicate glass, and includes one lead wire (5) for entering and exiting the wound bone.
A group of four oscillators (1
) is provided with a boundary groove (8) for each transducer group. If one input/output lead wire is connected to each vibrator, a T groove (8) is provided above all the cutting grooves (6). The groove (8) has a depth up to the middle of the thickness of the first acoustic matching layer (7), and the back surfaces of the first acoustic matching layer are connected to each other. The depth of the groove (8) is 8 so that the vibration of the adjacent first acoustic matching layer separated by the groove (8) is not transmitted.
In order to prevent the /N ratio and directivity from decreasing and to prevent the first acoustic matching 1 from breaking at the bottom of the groove (8) due to external force, It is desirable to set it between 1/2 and 3/4.

In the above configuration, the first acoustic matching layer (7) provided with grooves (8) in advance may be laminated onto the vibrator (1), but the positional deviation between the grooves (8) and grooves (6) can be minimized. To do this, after bonding the plate-shaped acoustic matching layer, grind it and make grooves (
8) is more appropriate. First acoustic matching layer (7
) is provided with a second acoustic matching layer (9) made of synthetic resin or the like, as in the prior art. Also - first acoustic matching @
Electrodes 0 and O are provided on the back surface of the vibrator (7) by vapor deposition, printing, plating, etc., and the electrodes 0 and α are electrically connected to the tortoise pole (2) of the vibrator (1). Furthermore, a ground lead (111) for extraction is connected to the end of the electrode ◇O, and the electrode α0 is used as a common ground electrode for the series of vibrators (1).

In FIG. 2, (a) indicates ultrasonic waves.

Effects of the invention (a) First acoustic matching layer (7) Grooves provided (8)
), but since the depth is halfway through the board thickness, there is no need to worry about cutting the vibrator even if grooves are formed after bonding.

Therefore, the vibrators are manufactured independently, and variations in sensitivity from vibrator to vibrator are extremely small, making it impossible to obtain a small and highly reliable vibrator.

(b) Since the grooves formed in the first acoustic matching layer are halfway through the thickness of the plate, they are not separated and are connected to each other on the back surface. Therefore, stress when an external force is applied is not dispersed to the joints with a large number of vibrators, the effective adhesive strength is extremely strong, and the joints with the vibrators do not separate.

(c) Since the electrode is provided on the back surface of the first acoustic matching layer, there is no need to attach a common ground lead wire to the surface electrode of the vibrator as in the conventional case. Therefore, as shown in FIG. The beam is symmetrical, and extremely good directivity can be obtained.

2) Since the conventional common ground lead wire provided separately is not required, the width of the ultrasonic probe can be made narrower and the size can be reduced accordingly. Additionally, the contact area between the electrode on the back side and the electrode on the front side of the vibrator is much larger than the contact area between the conventional common ground lead wire and the electrode, so there is a risk of non-conductivity due to poor contact. Not at all.

[Brief explanation of drawings]

Fig. 1 is a side view showing the main parts of the ultrasonic probe of the present invention;
The figure is a cross-sectional view of the same, Figure 3 is a side view showing the conventional example, and Figure 4 is a cross-sectional view of the same.
Loading material, (6) Cutting groove, (7) First acoustic matching layer, (8) Groove, (9) Second
acoustic matching layer, αO...common ground electrode. Agent Patent Attorney Mr. Oshima

Claims (1)

[Claims] (1) A vibrator consisting of a piezoelectric element with electrodes on its front and back surfaces is adhesively fixed onto a load material, cut grooves are provided at predetermined intervals to form multiple vibrator groups, and these vibrator groups are A first acoustic matching layer made of a borosilicate glass plate or the like is provided on the front surface, and has grooves having a depth halfway up the thickness of the plate formed for each transducer group, and furthermore, a first acoustic matching layer is provided on the front surface of the first acoustic matching layer. An ultrasonic probe characterized in that a second acoustic matching layer is provided on the top and a common ground electrode is provided on the back surface.