JPH0538335A - Ultrasonic probe and manufacture thereof - Google Patents

Abstract

PURPOSE:To suppress the side lobe level in the shorter axis direction by forming an electrode for each array element of one main plate of a piezoelectric element plate in an array shaped arrangement so that the area is larger at the center and reduced toward the edge part and dividing a vibration plate and the conductor layer of the other main plate divided by a plurality of grooves, into an array form in the arrangement direction. CONSTITUTION:The shape of an electrode 5 corresponding to each array element 4 of an array contactor element on one main plane 1 of a piezoelectric vibrator plate 3 is formed so that the area is larger at the center of the vibrator plate 3 in the shorter axis direction T of the array and is reduced toward the edge part, and weighting is performed in the shorter axis direction T. Further, a plurality of grooves 6 are formed in parallel to the arrangement direction S towards the main plane 1 from the other main plane 2, and the mechanical joint between the fine piezoelectric elements 13 in the shorter axis direction T is eliminated. Further, a conduct layer 7 is formed on the main plane 2, and the electric potential of the piezoelectric element 13 is made uniform, and the conductor layer 7 is used as the grounding of the vibrator plate 3, and the vibrator element plate 3 is array-divided in the arrangement direction S. Accordingly, the contactor can be manufactured easily and surely, and the side lobe level in the shorter axis direction can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe and its manufacturing method. For example, in order to obtain a clear image in a diagnostic device using an ultrasonic probe, it is necessary to use a finely focused ultrasonic beam.
On the other hand, in general, when an ultrasonic wave is transmitted from a piezoelectric vibrator at a uniform radiating sound pressure as shown in FIG. 10A, the ultrasonic wave radiation pattern is as shown in FIGS. Since the side lobe level becomes high and the ultrasonic beam cannot be narrowed down, as shown in FIG. 11, a method of transmitting the ultrasonic wave at the central portion of the piezoelectric vibrator becomes smaller toward the end (amplitude weighting). ) Is used.

According to this amplitude weighting, it is known that the side lobe level is greatly suppressed as shown in FIGS. 11 (b) and 11 (c), and the ultrasonic beam can be narrowed down.

On the other hand, the amplitude weighting of the array element 4 in the array type ultrasonic probe connected to the ultrasonic diagnostic apparatus is performed with respect to the scanning direction (arrangement direction S) of the probe as shown in FIG. Is a receiving amplifier A0 connected to the probe,
Although the gains of A1 and A2 are made large at the center of the aperture and become smaller toward the end, amplitude weighting in the minor axis direction T perpendicular to the scanning direction is not generally performed, and the direction is shortened. There has been a demand for an effective method of amplitude weighting in.

In FIG. 12, 5 is an electrode and 11 is a backing.

[0005]

2. Description of the Related Art As a method for suppressing side lobe levels by weighting amplitude in the short axis direction T, the
As shown in FIG. 13, with respect to the short-axis direction T of the array type ultrasonic probe, as indicated by an arrow in the figure, the polarization intensity 12 is large in the central portion of the array element 4 and gradually increases toward the end. As shown in FIG. 14, the size of each arrayed array element 4 is widened in the central part and narrowed toward both ends with respect to the minor axis direction T of the array type ultrasonic probe. Was proposed.

[0006]

However, in the structure shown in FIG. 13, the polarization intensity 12 of the array element 4 depends on the polarization voltage, polarization temperature, polarization time, etc. at the time of polarization, so that the desired polarization intensity is obtained. 12 is difficult to obtain with the desired distribution,
In the structure shown in FIG. 14, cracks and chips are likely to occur at the end portions of the array array element 4 processed so that both end portions are narrowed, and further, the center portion of the array array element 4 and both end portions tapered The part has a drawback that the resonance frequency of the ultrasonic wave emitted is different due to the shape effect.

The present invention has been made to solve the above drawbacks, and an ultrasonic probe capable of suppressing the side lobe level in the minor axis direction and being easy to manufacture,
And a method for manufacturing the same.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above object is to control an ultrasonic beam by using a large number of transducers arranged in an array as shown in FIG. 1 corresponding to an embodiment. In the acoustic probe, the shape of the electrode 5 corresponding to each array element 4 of the probe on one main surface 1 of the piezoelectric vibrator plate 3 having the two main surfaces 1 and 2 is defined by the array direction S of the array.
The piezoelectric vibrator plate 3 has a large area in the center in the short axis direction T orthogonal to the direction and is formed so as to become narrower toward the end, and from the other main surface 2 of the piezoelectric vibrator plate 3 to the arrangement direction S. , A plurality of grooves 6 are provided in parallel with each other, and a conductor layer 7 is provided on the main surface 2 divided by the groove 6 to short-circuit each divided portion on the main surface 2 and This is achieved by providing an ultrasonic probe characterized by dividing the piezoelectric vibrator plate 3 and the piezoelectric vibrator plate 3 into an array in the array direction S.

Further, as shown in FIG. 7, the shape of the electrode 5 may be stepwise so that the peripheral edge thereof is on the groove 6 provided in parallel with the arrangement direction S or the groove 8 by the array division. It is also possible to form the acoustic matching layer 9 by forming the conductor layer 7 so that the thickness of the conductor layer 7 is about λ / 4 at the center frequency of the ultrasonic wave emitted by the probe. It is also possible to form one or more acoustic matching layers 9 on the layer 7 by using a material whose acoustic impedance is smaller than that of the conductor layer 7.

When the acoustic lens 10 is arranged on the front surface of the piezoelectric vibrator plate 3 as described above, the focus of the acoustic lens 10 is set to a depth of 2/3 or more of the maximum diagnostic depth of the ultrasonic diagnostic apparatus. Is desirable.

Further, the above ultrasonic probe has an area at the center of the piezoelectric vibrator plate 3 in the minor axis direction T on one main surface 1 of the piezoelectric vibrator plate 3 having two main surfaces 1 and 2. Electrode 5 having a large width and narrowing toward the end is formed corresponding to each array element 4 of the probe, and then a backing 11 is formed on the one main surface 1 and then the main surface 1 is formed. A plurality of grooves 6 are cut parallel to the arrangement direction S from the other main surface 2 facing to each other, and then a conductor layer 7 is provided on the main surface 2 divided into a plurality of parts by the grooves 6, and then a conductor layer is formed. 7 and the piezoelectric vibrator plate 3 are array-divided in the array direction S, which is obtained by a method for manufacturing an ultrasonic probe.

[0012]

In the present invention, the shape of the electrode 5 corresponding to each array element 4 of the array probe is formed on one principal surface 1 of the piezoelectric vibrator plate 3 having the two principal surfaces 1 and 2 by the short axis of the array. In the direction T, the piezoelectric vibrator plate 3 has a large area in the center and a narrower area toward the ends, and weighting is performed in the minor axis direction T.

Further, a plurality of grooves 6, 6, ... Are provided in parallel with the arrangement direction S from one main surface 2 of the piezoelectric vibrator plate 3 toward the other main surface 1, and are minute in the minor axis direction T. The mechanical coupling between the piezoelectric elements 13 is removed.

Further, a conductor layer 7 is formed on the main surface 2 on the side where the groove 6 is formed, the electric potential of the micro piezoelectric element 13 on the main surface 2 is made uniform, and the ground of the piezoelectric vibrator plate 3 is formed. It is said that.

The array type ultrasonic probe is formed by dividing the piezoelectric vibrator plate 3 in the array direction S into an array.
The split grooves 8, 8 ... Remove mechanical coupling in the arrangement direction S.

Under the above construction, the minor axis direction T and the arrangement direction S
Since the groups of micro array elements 13 formed by the grooves 6 and 8 of all have the same rectangular shape, the emission of ultrasonic waves at partially different resonance frequencies is prevented, and the tip of each transducer is Since it does not have a sharp shape, cracks and chips during processing can be prevented.

According to the second aspect of the invention, the electrode 5 is formed into a collective shape of the minute piezoelectric elements 13.
Unnecessary vibration is prevented. Further, in the inventions according to claims 3 and 4, the acoustic matching layer 9 is formed by utilizing the conductor layer 7 to increase the amplitude of ultrasonic waves and widen the band of the probe.

In the invention of claim 5, which is directed to an ultrasonic probe having an acoustic lens 10 arranged on the front surface of the piezoelectric vibrator plate 3, the focus of the acoustic lens 10 is set to the maximum diagnostic value of the ultrasonic diagnostic apparatus. The depth is set to ⅔ or more of the depth, and a good beam shape can be maintained up to a long distance area.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. 2 to 6 show an embodiment of the present invention. First, an electrode 5 is formed on one main surface 1 of a piezoelectric vibrator plate 3 having two main surfaces 1 and 2. This electrode 5 is formed corresponding to each array element 4 of the array probe by using a means such as baking or vapor deposition of silver, and is orthogonal to the array direction S of the array as shown in FIG. 1 (b). In the short axis direction T, the area is wide at the center of the piezoelectric vibrator plate 3 and has a rhombus shape that becomes narrower toward the ends.

It is to be noted that FIG. 1A shows another main surface 2 opposed to the one main surface 1, and preferably, the electrode 5 is formed on the entire surface by the same method. Thereafter, as shown in FIG. 3, the flexible printed board 14 is fixed to the main surface 1 on which the diamond-shaped electrodes 5 are formed, the leads 15 are drawn out from the electrodes 5 corresponding to each array element 4, and then, In order to absorb unnecessary ultrasonic waves emitted from the main surface 1,
Attach the backing 11. This backing 11 is
In addition to absorbing ultrasonic waves, it also functions as a damper,
The ringing of the ultrasonic pulse emitted from the main surface 2 on the ultrasonic emission side is suppressed.

Thereafter, as shown in FIG. 4, grooves 6, 6, ... Are provided in parallel with the arrangement direction S from the radiation-side main surface 2 of the piezoelectric vibrator plate 3 toward the facing main surface 1. .. The groove 6 is formed by using a dicing saw or the like, and the cutting depth is such that the electrodes 5 formed on the facing main surfaces 1 and 2 are not separated. In order to prevent interference of the vibration of the
It is formed with a cutting depth of not less than%.

Next, as shown in FIG. 5, a metal foil 16 for grounding is fixed on the main surface 2 on the radiation side.
The metal foil 16 is fixed to both edge portions along the arrangement direction S of the main surface 2 and is pulled out to the side. Further, a conductor layer 7 made of a conductive paste or the like is provided on the main surface 2 so as to sandwich the metal foil 16, and each divided portion is made to have the same potential to form the ground of the piezoelectric vibrator plate 3. To be done.

Thereafter, as shown in FIG. 6, the conductor layer 7 and the piezoelectric vibrator plate 3 are array-divided in the array direction S, and then an acoustic lens (not shown) is attached to the upper surface of the conductor layer 7 and the ultrasonic probe. The child is constructed.

A second embodiment of the present invention is shown in FIG. In this embodiment, the electrode 5 is formed in units of the minute piezoelectric element 13, and its peripheral edge is a groove 6 provided in parallel with the arrangement direction S and a stepwise peripheral edge divided by the groove 8 in the array division. Have As a result, the electrodes 5 are formed on the entire surface of the micro-piezoelectric element 13 to be driven, and unnecessary vibration is prevented.

FIG. 8 shows a third embodiment of the present invention, in which the depth d of the grooves 6, 6, ... Cut into the surface on which the electrode 5 is formed.
Shows a case where is equal to or larger than the plate thickness of the piezoelectric vibrator plate 3.
As a result, the groove 6 reaches the middle portion in the thickness direction of the electrode 5, and the mechanical coupling in the minor axis direction T is further reduced.

In this case, it is necessary to prevent the electrode 5 from being divided by the groove 6. FIG. 9 shows a fourth embodiment of the present invention. This embodiment utilizes that the conductor layer 7 provided on the main surface 2 divided by the groove 6 provided in parallel with the arrangement direction S of the piezoelectric vibrator plate 3 is made of a resin material such as a conductive paste. And (a) is a single-layer matching, and (b) is a two-layer structure in which another material is provided on the conductor layer 7 and whose acoustic impedance is smaller than that of the conductor layer 7. The case of matching is shown.

The thickness of these acoustic matching layers 9 is set to be about λ / 4 of the center frequency of the ultrasonic wave emitted by the probe, and the amplitude of the ultrasonic wave emitted from the probe is As it gets larger, the band of the probe becomes wider.

It should be noted that the acoustic lens 1 is used in comparison with the above embodiments.
When 0 is set, it is desirable to set the focus of the acoustic lens 10 to a depth d that is 2/3 or more of the maximum diagnostic depth d of the ultrasonic diagnostic apparatus to which these ultrasonic probes are connected. ..

[0029]

As is apparent from the above description, according to the present invention, it is possible to easily and surely manufacture the array type probe for forming the amplitude weighting on the ultrasonic waves to be transmitted or received. You can

By weighting the amplitude, it is possible to suppress the side lobe level in the short axis direction. As a result, the ultrasonic beam can be improved over a wide range from a short distance to a long distance.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a first step of the present invention, in which (a) is a diagram showing one main surface and (b) is a diagram showing an opposite main surface.

FIG. 3 is a diagram showing a second step of the present invention.

FIG. 4 is a diagram showing a third step of the present invention.

FIG. 5 is a diagram showing a fourth step of the present invention.

FIG. 6 is a diagram showing a fifth step of the present invention.

FIG. 7 is a diagram showing a second embodiment of the present invention.

FIG. 8 is a diagram showing a third embodiment of the present invention.

FIG. 9 is a diagram showing a fourth embodiment of the present invention,
(A) is a figure which shows 1-layer matching, (b) is a figure which shows 2-layer matching.

FIG. 10 is a diagram showing ultrasonic radiation from a piezoelectric element.

11A and 11B are diagrams showing ultrasonic radiation by weighting, wherein FIG. 11A is a diagram showing a distribution of radiated sound pressure, FIG. 11B is a diagram showing a radiation pattern, and FIG. 11C is a diagram showing a beam shape. ..

FIG. 12 is a diagram showing a weighting method.

13A and 13B are diagrams showing a conventional example, FIG. 13A is a diagram showing a distribution of radiated sound pressure, and FIG. 13B is a diagram showing a polarization state.

14A and 14B are diagrams showing another conventional example, wherein FIG. 14A is a diagram showing a distribution of radiated sound pressure, and FIG. 14B is a diagram showing a polarization state.

[Explanation of sign]

 1, 2 main surface 3 piezoelectric vibrator plate 4 element 5 electrode 6, 8 groove 7 conductor layer 9 acoustic matching layer 10 acoustic lens 11 backing S array direction T minor axis direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroshi Ishikawa, 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, within Fujitsu Limited

Claims (6)

[Claims] 1. An ultrasonic probe for controlling an ultrasonic beam using a large number of transducers arranged in an array, comprising: a piezoelectric transducer plate (3) having two principal surfaces (1, 2). The shape of the electrode (5) corresponding to each array element (4) of the probe on one principal surface (1) is set to the piezoelectric vibration in the minor axis direction (T) orthogonal to the array direction (S) of the array. The sub-plate (3) has a large area in the center and is formed to be narrower toward the end, and is parallel to the arrangement direction (S) from the other main surface (2) of the piezoelectric vibrator plate (3). A plurality of grooves (6, 6 ...) Are provided, a conductor layer (7) is provided on the main surface (2) divided by the groove (6), and each divided portion on the main surface (2) is provided. An ultrasonic probe characterized in that the conductor layer (7) and the piezoelectric vibrator plate (3) are divided into an array in the array direction (S) while being short-circuited. 2. The electrode (5) has a stepped shape such that its peripheral edge is on a groove (6) provided in parallel with the array direction (S) or a groove (8) formed by the array division. The ultrasonic probe according to claim 1, wherein: 3. The acoustic matching layer (9) according to claim 1, wherein the conductor layer (7) is formed to have a thickness of about λ / 4 at a center frequency of ultrasonic waves emitted by the probe. The ultrasonic probe described. 4. The acoustic matching layer (9) according to claim 1, wherein one or more acoustic matching layers (9) are formed on the conductor layer (7) with a material having an acoustic impedance smaller than that of the conductor layer (7). Ultrasonic probe. 5. An acoustic lens on the front surface of the piezoelectric vibrator plate (3).
The ultrasonic probe in which (10) is arranged, wherein the focus of the acoustic lens (10) is set to a depth of 2/3 or more of the maximum diagnostic depth of the ultrasonic diagnostic apparatus. The ultrasonic probe according to 2, 3, or 4. 6. A method of manufacturing an ultrasonic probe for controlling an ultrasonic beam using a large number of vibrators arranged in an array, the piezoelectric vibrator having two main surfaces (1, 2). On one main surface (1) of the plate (3), an electrode (5) having a shape in which the area is wide at the center of the piezoelectric vibrator plate (3) in the minor axis direction (T) and becomes narrower toward the end is searched. It is formed corresponding to each array element (4) of the tentacle, and then a backing (11) is formed on the one main surface (1), and then another main surface (1) facing the main surface (1) is formed. A plurality of grooves (6, 6 ...) Are cut in parallel with the arrangement direction (S) from 2), and then a conductor layer (7) is formed on the main surface (2) divided into a plurality of grooves by the grooves (6). ), The conductor layer (7) and the piezoelectric vibrator plate (3)
Is divided into arrays in the array direction S, a method for manufacturing an ultrasonic probe.