JPH0628880Y2 - Ultrasonic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an ultrasonic transducer used for medical diagnosis, non-destructive inspection, and the like.

(Prior Art and its Problems) FIG. 4 is a vertical sectional view of a conventional ultrasonic transducer. The basic structure of this ultrasonic transducer is the same as that disclosed in Japanese Patent Application Laid-Open No. 55-151891, in which a rear surface support 1 having a concave lower surface is provided with an IEEE standard.
1982 Ultrasonics Symposium Proceeding (p.832〜
836), the back surface of the flexible substrate is formed by bending and covering a flexible substrate having a plurality of back electrodes arranged in a horizontal row and lead wires connected to these back electrodes on the same surface. The electrode portion 2 is superposed on the lower surface of the back support 1. Further, on the back electrode portion 2, a polymer piezoelectric film 3, an operating surface side electrode 4 and a protective layer 5 are further laminated in order to form a short circuit between the back electrode portion 2 and the operating surface side electrode 4. In order to prevent this, the polymer piezoelectric film 3 is dimensioned slightly larger than the back electrode portion 2. The operating surface side electrode 4 covering the entire array element composed of the back electrode portion 2 and the polymer piezoelectric film 3 is formed by subjecting the upper surface of the protective layer 5 to a metalizing process.
The operating surface side electrode 4 is connected to the ground circuit via the lead wire 6 from the extension portion 5a formed by partially extending the end portion in the element arrangement direction. In FIG. 4, 7 is the lead wire portion of the flexible substrate bent upward along the side surface of the back support 1, 8 and 9 are the upper half and lower half of the outer case, and 10 is the outer case. A shield conductor formed inside, a spacer 11 for preventing a short circuit between the lead wire portion 7 and the shield conductor 10, and 12 and 13 connecting the lead wire portion 7 and an impedance matching element (not shown). Connector.

By the way, in the ultrasonic transducer having the above-mentioned configuration, the piezoelectric film 3 is dimensioned larger than the back electrode portion 2 in order to prevent a short circuit between the back electrode portion 2 and the operating surface side electrode 4. When the bending diameter of the lead wire portion 7 that can be bent at 90 ° or more at the boundary is large, ultrasonic waves are generated from the bent portion of the lead wire portion 7, disturbing the normal sound field and generating a virtual image. There is a problem that a good image cannot be obtained. In order to avoid this, the bending diameter of the flexible substrate may be reduced, but in that case, a new problem arises in that the conductor of the lead wire portion 7 is broken and broken at the bent portion.

Further, in order to connect the operating surface side electrode 4 to the ground circuit, an extension portion 5a formed at an end portion of the protective layer 5 in the element arrangement direction (direction perpendicular to the paper surface of FIG. 4) is bent upward, and the extension portion 5a is formed.
The back support 1 is connected through the twisted lead wire 6.
Since the lower surface of the above is processed into a semi-cylindrical concave surface along the element array direction, the extension 5a cannot be bent without difficulty. For example, when a resin film is used as the protective layer 5, the protective layer 5 is distorted due to the bending of the extension portion 5a, so that it does not follow the lower surface of the back support 1 and is strongly peeled off. Therefore, in order to avoid this, bending is performed by adding a cut or a notch to the base end side of the extension portion 5a, but water or chemicals intrudes through the cut or the notch during use, so that water resistance However, there is a drawback that the chemical resistance is lowered and the reliability of the apparatus is lowered. Further, the entire element of this ultrasonic transducer is constructed so as to be electrostatically shielded by being wrapped with the operating surface side electrode 4 formed on the protective layer 5 and the shield conductor 10 formed inside the outer case. However, there is also a drawback that the shield effect is reduced due to the cuts and notches added to the extension 5a of the protective layer 5.

(Object of the Invention) The present invention has been made to solve the above problems, and an object thereof is to provide an ultrasonic transducer capable of displaying a high-quality image with high reliability and improving workability in assembling. .

(Means for Achieving the Purpose) In order to achieve the above-mentioned object, an ultrasonic transducer of the present invention comprises a flexible substrate having a plurality of rear electrodes arranged and lead wires connected to these rear electrodes. While bending and covering the back support so that the back electrode portion overlaps the lower surface thereof, an insulating side plate having a knife edge-shaped lower end portion is applied to the lead wire portion of the flexible substrate, and the back electrode portion to the insulating side plate. The polymer piezoelectric film is superposed on the portion extending over the lower end of the polymer piezoelectric film by the conductor case in which the lower end is sealed by the protective layer on which the operating surface side electrode is formed. The back support, the flexible substrate and the piezoelectric polymer film are coated so as to overlap with. According to this ultrasonic transducer, the flexible substrate is bent by the edge-shaped lower end of the insulating side plate which is interposed between the bent portion of the lead wire portion which is bent at the back electrode portion and the piezoelectric piezoelectric film. While preventing the generation of ultrasonic waves from the bent portion without reducing the diameter, the entire back support, flexible substrate, and polymer piezoelectric film are covered by a conductor case with a one-side sealed structure in which the lower end is sealed with a protective film. By covering the inside of the back support with a transparent electrode, the back electrode part of the flexible substrate, the polymer piezoelectric film, and the conductor case are sequentially installed on the bottom surface of the back support. Assembly can be done by simple stacking work.

(Embodiment) FIG. 1 and FIG. 2 are enlarged vertical sectional views of an essential part of an ultrasonic transducer which is an embodiment of the present invention (second embodiment).
The drawing shows a vertical sectional view perpendicular to the cross section of FIG. 1, and FIG. 3 shows a schematic configuration diagram of the entire ultrasonic transducer.

In this ultrasonic transducer, a flexible substrate F having a plurality of back electrodes (not shown) arranged in a horizontal row and lead wires 23a (Fig. 2) respectively connected to the back electrodes formed on the same surface is bent. The back electrode portion 22 of the flexible substrate F is adhered along the lower surface of the back support 21, and the lead wire portions 23 having the lead wires 23a are attached along the left and right side surfaces of the back support 21. . As shown in FIG. 1, the lower surface of the back support 21 is provided with a semi-cylindrical concave surface extending in a direction perpendicular to the paper surface for the purpose of focusing ultrasonic waves, and the back electrode portion 22 of the flexible substrate F is The back electrodes are arranged along the lower surface with the direction of arrangement of the back electrodes aligned in the direction perpendicular to the paper surface, and the lead wire portion 23 of the flexible substrate F is upwardly spaced at an angle of 90 ° or less with the back electrode portion 22 as a boundary. It is arranged along the left and right side surfaces of the folded back support 21. Then, the bent portion of the lead wire portion 23 is set to 0. so that the lead wire 23a is not broken and broken.
It is bent with a bending diameter of 3 mm or more. Further, the left and right lead wire portions 23 of the flexible board F are provided with insulating side plates 24 each having a lower end formed in a knife edge shape. Further, a polymer piezoelectric film 25 having a size slightly larger than the back electrode portion 22 is laminated and adhered on the back electrode portion 22, and both ends of the polymer piezoelectric film 25 protruding from the back electrode portion 22 are formed on the insulating side plate 24. It is bonded to the edge-shaped lower end. Therefore, the polymer piezoelectric film 2
The knife edge-shaped lower end portion of the insulating side plate 24 is interposed between the end portion 5 and the bent portion of the flexible substrate F.

Reference numeral 26 is a case made of a conductor, and the lower end side opening of the case body 26a is closed by a protective layer 27 made of resin. In addition, an operating surface side electrode 28 is previously formed on the upper surface of the protective layer 27 by a metallizing technique such as sputtering, vapor deposition, or plating. Then, the back support 21, the flexible substrate F, and the polymeric piezoelectric film 25 are covered from below by the case 26 having the one-side closed structure, and the protective layer 27 is superposed on the polymeric piezoelectric film 25 via the operating surface side electrode 28. To be glued. The case 26 that is a conductor
Since the insulating side plate 24 is interposed between the lead wire portion 23 of the flexible substrate F and the lead wire portion 23 of the flexible substrate F, the lead wire portion 2
3 and the case 26 are prevented from being short-circuited. The resin used as the material of the protective layer 27 is selected from polyester, polyimide, polyethylene and others depending on the application of the ultrasonic transducer. The closing by the protective layer 27 on the lower end side of the case 26 is achieved by soldering the operating surface side electrode 28 at the peripheral edge portion of the protective layer 27 to the outer surface of the flange portion 26b formed on the lower end of the case main body 26a over the entire circumference. Has been done. Alternatively, the case 26 may be formed thick, and the lower surface of the case 26 may be closed by soldering the operating surface side electrode 28 of the protective layer 27 to the lower end surface thereof.

The laminated structure of the back electrode portion 22, the polymer piezoelectric film 25, and the operating surface side electrode 28 constitutes an array transducer corresponding to the electrode array of the back electrode portion 22. The transducer array portion configured as described above is provided in the case 26 having the one-sided closed structure.
The inner surface of the outer case is covered with the shield conductor 29, and the inner surface of the outer case is housed in the lower half of the outer case 30.

The lead wire 23a connected to each back electrode (normally 64 to 84 pieces) of the back electrode portion 22 is connected to the matching circuit board 32 made of a solid board such as glass epoxy on which the impedance matching element 31 is mounted. 33
On the other hand, each signal line 35a of the coaxial cable 35 which is bound, fastened or molded and solidified by the fastening portion 34 is connected to the matching circuit board 32. Further, the case 26 is connected to the lead wire 3 as shown in FIG.
6, lead wire 23b for exclusive use of ground and lead wire plate 33
Connected to the signal ground of the matching circuit board 32 via
As a result, the case 26 is configured to serve as the ground of all array transducers. Furthermore, the matching circuit board 3
2. A portion formed by connecting the coaxial cables 35 is an outer case upper half portion 37 whose inner surface is covered with a shield conductor 29.
And the shield conductors 29 of the outer case upper half portion 37 and the outer case lower half portion 30 are connected to the collective shield conductor of the coaxial cable 35 to form a frame ground. The coaxial cable 35 is connected to the transmitting / receiving circuit 38.

Next, the operation of this ultrasonic transducer will be described. When the high frequency pulse oscillated by the transmission / reception circuit 38 is applied to the polymeric piezoelectric film 25 via the matching circuit substrate 32, it is converted into ultrasonic waves by the polymeric piezoelectric film 25 and projected as ultrasonic pulses. The projected ultrasonic pulse travels in the living body or the subject, and generates a reflected pulse at the boundary of acoustic impedance such as a lesion or a defect. The reflected pulse is received by the piezoelectric polymer film 25 and converted into an electric high frequency pulse. Then, the high-frequency pulse is detected by the transmission / reception circuit 38 via the matching circuit board 32, and the detection signal is subjected to appropriate imaging processing by the signal processing / control circuit 39 and then sent to the CRT 40, whereby the living body or the subject is inspected. The internal image of is displayed on the CRT 40.

In this ultrasonic transducer, as described above, the knife edge-shaped lower end portion of the insulating side plate 24 is interposed between the bent portion of the lead wire portion 23 of the flexible substrate F and the end portion of the polymer piezoelectric film 25. Therefore, even if the bending diameter of the bent portion is increased to some extent, an ultrasonic wave that causes a virtual image is not generated from the bent portion, and therefore the lead wire 23a can be easily disconnected without breaking the flexible substrate. The folding can be performed and the deterioration of the image caused thereby is also avoided.

Further, since the entire array vibrator is covered with the case 26 having a one-sided closed structure in which the lower end side is sealed with the protective layer 27, water and chemicals do not enter the inside with use. Moreover, since the arrayed oscillator is entirely wrapped by the one-side blocking structure including the conductive case 26 and the protective layer 27 on which the operating surface side electrode 28 is formed, a sufficient electrostatic shield is provided, which allows Induced noise is not generated even when it comes into contact with the human body, and capacitive coupling between the vibration elements is suppressed, so that the separation performance between the vibration elements is improved. Further, on the lower surface of the back support 21, the back electrode portion 2 of the flexible substrate F is
2. Since the polymer piezoelectric film 25 and the case 26 and the protective layer 27 integrated with the case 26 are assembled by a simple work of sequentially stacking and adhering, the assembling workability is also improved.

In this embodiment, a metal material is used as the case body 26a in order to have conductivity, but a resin may be used instead of the metal material.
It suffices that the outer surface of a is metallized to give conductivity, and the operating surface side electrode 28 formed on the protective layer 27 is soldered to the outer surface of the case body 26a over the entire circumference. Separately from this, the case body 26a and the protective layer 27
May be integrally molded with a resin to form the one-side closed structure case 26, and the entire inner surface thereof may be metalized.

In the above embodiment, a case where a solid substrate such as glass epoxy is used as the matching circuit substrate 32 is shown.
Not limited to this, a flexible substrate in which the back electrode, its lead wire, and the matching circuit are integrally patterned may be used.

Further, although the case where the back electrodes are arranged in one horizontal line is illustrated here, the present invention is not limited to this, and the present invention can be applied to an ultrasonic transducer of a type in which the back electrodes are arranged vertically and horizontally. Further, it is needless to say that the present invention can be applied not only to this embodiment in which the array of the vibrators is horizontal, but also to a structure in which the vibrators are arrayed on a surface curved in an uneven shape.

(Effects of the Invention) As described above, according to the ultrasonic transducer of the present invention, there is no risk of disconnection of the lead wire during assembly, water or chemicals entering inside during use, and a sufficient electrostatic shield is also provided. It is possible to obtain high reliability and to measure, high quality image can be displayed, and assembly workability can be greatly improved.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an ultrasonic transducer according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of another essential part of the ultrasonic transducer, and FIG. A schematic configuration diagram showing the entire transducer,
FIG. 4 is an enlarged cross-sectional view of the main part of the conventional example. 21 ... Rear support, 22 ... Rear electrode part, 23 ... Lead wire part, 24 ... Insulating side plate, 25 ... Polymer piezoelectric film, 26 ... Case (conductor case), 27 ... Protective layer, 28 ... Operating surface side electrode, F: Flexible substrate

Claims (1)

[Scope of utility model registration request] 1. A flexible substrate having a plurality of arrayed back electrodes and lead wires connected to these back electrodes is bent, and a back support is coated on the lower surface thereof so that the back electrode portions overlap. On the other hand, an insulating side plate having a knife edge-shaped lower end portion is applied to the lead wire portion of the flexible substrate, a polymer piezoelectric film is overlapped with a portion extending from the back electrode portion to the lower end portion of the insulating side plate, and an operating surface side electrode is formed. The back support, flexible substrate, and polymer piezoelectric film were coated by a conductor case whose lower end was sealed with a protective layer so that the protective layer overlaps the polymer piezoelectric film via the electrode on the operating surface side. An ultrasonic transducer characterized by the following.