JPH10136491A - Ultrasonic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately pull a signal line out of the electrode of a piezoelectric panel by providing plural flexible printed circuit boards(FPC) forming wiring patterns, and preventing these respective FPC from being divided through the dividing process of piezoelectric body in production. SOLUTION: Plural FPC 2-5 are used for pulling the signal line out of a vibrating element, which is formed by dividing a positive electric ceramics panel 1, in the manner of block. The respective FPC 2-5 are not divided through the dividing process of piezoelectric body in production. Then, a gap between the edge wiring pattern of FPC 2-5 and the adjacent wiring pattern is made narrower than the arrangement pitch of the other wiring pattern and a gap between the adjacent edge wiring patterns of adjacent FPC 2-5 is made wider than the arrangement pitch of the other wiring pattern. Thus, it is not necessary to form any slit on the FPC 2-5 and the vibrating element of ultrasonic transducer having the narrow arrangement pitch can be highly accurately dealt with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic transducer for outputting ultrasonic waves using a piezoelectric body in which a plurality of piezoelectric vibrators formed of piezoelectric ceramics are arranged in a line and receiving the reflected ultrasonic waves. About.

[0002]

2. Description of the Related Art An ultrasonic transducer used in an ultrasonic diagnostic apparatus and a flaw detector uses a piezoelectric vibrator as an element for transmitting and receiving ultrasonic waves. At present, an array-type ultrasonic transducer capable of performing electronic focusing in which a number of transducers are arranged in a line is most frequently used.

In this array-type ultrasonic transducer, it is necessary to connect a lead wire and a ground wire in order to transmit and receive signals to and from the electrodes of a large number of elements (piezoelectric vibrators). That is, a transmission signal (control signal) is output from the control circuit to each element through this lead, and a reception signal is input from each element to the signal processing circuit through this lead. As a method of connecting the lead wire and the ground wire to the electrode of each element, a method of connecting a flexible printed wiring board to an electrode surface, a method of connecting a lead wire to a turn-around electrode portion on a side surface of a vibrator, and the like are generally used. Has been taken.

[0004] As a method of connecting a flexible printed wiring board to a vibrator electrode, a method using soldering, a conductive adhesive, welding, an anisotropic conductive film or the like is generally known. In general, as a material of a vibrator electrode, a baked silver electrode is most often used in conventional piezoelectric ceramics, whereas a metal thin film formed by sputtering, vapor deposition, plating, or the like is used in a composite piezoelectric material.

[0005] As a method of extracting the drive electrode of the ultrasonic transducer, there is a method of connecting a flexible printed circuit board (FPC) to the electrode of the piezoelectric plate, and utilizing the wiring pattern of the FPC. In this withdrawal method,
After electrically connecting a single FPC to the piezoelectric plate, the piezoelectric plate and FP
By cutting C with the FPC wiring pattern, an arrayed ultrasonic transducer is realized. As a method of realizing a convex (convex) shape ultrasonic transducer, a piezoelectric plate and an FPC are cut, then bent into a convex shape in the array direction, and a gap between FPC wiring patterns provided in the FPC in advance, and A method has been developed in which an FPC is folded and stored using a slit reaching the vicinity of the piezoelectric plate.

As shown in a top view of FIG. 12A, a side view of FIG. 12B, and FIG. 15, an ultrasonic transducer includes an FPC 102 on a piezoelectric plate 101 and a backing material 103.
Is partially sandwiched. FPC102
Has a wiring pattern (lead wire) 1 made of copper or the like.
04-1 to 104-16 are formed, and the wiring pattern 1
Gap between 04-4 and 104-5, wiring patterns 104-8 and 1
Gap with 04-9, wiring patterns 104-12 and 104-13
And preliminary slits 105-1 to 105-3 are formed in the gap between them.

The wiring patterns 104-1 to 104-1 of the FPC 102
The piezoelectric plate 101 is fixed to the surface on which the 04-16 is formed,
The electrodes of the piezoelectric plate and the respective wiring patterns 104-1 to 104-16 are electrically connected. The backing material 103 is fixed to the back surface of the piezoelectric plate 101 to improve acoustic characteristics. As shown in FIG. 13, the intervals between the wiring patterns 104-1 to 104-16 on the FPC 102 are formed so as to gradually increase in the direction away from the piezoelectric plate 101 so as to facilitate signal extraction. ing.

As shown in the top view of FIG. 14A and the side view of FIG. 14B, the ultrasonic transducer divides the above-described structure based on each of the wiring patterns 104-1 to 104-16. This forms an array type ultrasonic transducer. That is, the piezoelectric plate 101 has 16 piezoelectric plates (piezoelectric elements, vibration elements) 101-1 to 1 corresponding to the 16 wiring patterns 104-1 to 104-16 in a one-to-one correspondence.
01-16, and the FPC 102
05-1 to 105-3, four divided substrates 102-1 to 1
02-4. However, the backing material 103
Although the slit groove is formed, the ultrasonic transducer is held as an integral type without being divided. In addition,
Before and after the dividing step, formation of an acoustic matching layer, extraction of an earth electrode, and the like are performed.

Further, in order to form a convex shape, the backing material 103 is made of
Each of the divided substrates 102-1 of the FPC 102 is bent in a convex shape along the array arrangement direction of 101-16 as shown in FIG.
The ultrasonic transducer can be handled with good storability by bending the to-102-4 and overlapping them as shown in FIG.

In the ultrasonic transducer of the electronic scan system, the scanning direction (the direction of array of the ultrasonic transducers)
Since the sound field formation is performed electronically, the arrangement pitch of the vibrating elements in the array arrangement direction is made small and fine in order to improve the sound field characteristics.
FIG. 17 is a cross-sectional view showing a schematic configuration of a slice direction (a direction orthogonal to an array direction of ultrasonic transducers) of an electronic scan type ultrasonic transducer.

This ultrasonic transducer has a piezoelectric ceramic layer 111 as an intermediate layer and an acoustic matching layer 11 as an upper layer.
2 is formed, and a backing material 113 is formed in a lower layer. Further, an acoustic lens 114 is provided on the acoustic matching layer 112 (on the side of the ultrasonic transmitting / receiving surface).

Although not shown, the piezoelectric ceramic layer 111 has a plurality of piezoelectric elements (vibrating elements) arranged in an array arrangement direction (a direction perpendicular to the plane of the drawing). The matching layer 112 is also divided, and the upper surface of the backing material 113 is also shaped accordingly. A common electrode is formed on the upper surface of the piezoelectric ceramic layer 111 (boundary surface with the acoustic matching layer 112), and this common electrode is connected to ground (0 [V]). A drive electrode is formed on the lower surface of the piezoelectric ceramic layer 111 (boundary surface with the backing material 113), and an FPC 115 is interposed between the piezoelectric ceramic layer 111 and the backing material 113. Each individual electrode is electrically connected to the wiring pattern of the FPC in a one-to-one correspondence. The acoustic lens has a function of converging ultrasonic waves in the slice direction, and forms an optimal sound field.

As shown in FIG. 18, a lower surface (back surface = lower surface) of a piezoelectric body (vibration element) 121 of the ultrasonic transducer is provided.
Drive electrode 1 formed on the surface opposite to the ultrasonic wave output surface)
In order to draw out the signal line and the ground line from the common electrode 123 formed on the upper surface 22 (the front surface = the output surface of the ultrasonic wave), first, the common electrode 123 is routed to the back surface of the piezoelectric body 121 to draw the signal line. Of the signal FPC 124 is connected to the drive electrode 122 by soldering or the like, and the tip of an earth plate 125 for leading out an earth wire is connected to a portion routed to the back of the common electrode 123 by soldering or the like. doing. The FPC 124 and the electrodes 122, 1
23 and the backing material 126.
And an acoustic matching layer 127 are formed on the back surface and the front surface of the piezoelectric body 121, respectively.

[0014] Further, in order to improve the diagnostic performance, an ultrasonic transducer with higher resolution is required, and a resin is injected into the gap between the columnar piezoelectric ceramics and electrodes are formed on the front surface (ultrasonic transmission / reception surface) and the back surface. An ultrasonic transducer using the composite piezoelectric body as a piezoelectric plate has been developed. This composite piezoelectric body increases the efficiency of the ultrasonic transducer by converting the piezoelectric ceramic into electric and ultrasonic waves by making the piezoelectric ceramic into a columnar and small shape, and increases the sensitivity of the ultrasonic transducer. In this case, the acoustic impedance of the piezoelectric plate is improved by reducing the acoustic impedance of the piezoelectric plate.

An example of a method for manufacturing a composite piezoelectric body will be described below. First, on one surface of a piezoelectric ceramic plate 121 as shown in FIG. 19 (a), as shown in FIG. 19 (b), a lattice-shaped groove 122 is formed at a predetermined depth by a dicing machine or a wire saw. Form. That is, the surface on the opposite side of the piezoelectric ceramic plate 121 is left as it is. Next, as shown in FIG.
22 is filled with an epoxy resin and cured by heating or room temperature. After the epoxy resin has completely cured, FIG.
As shown in FIG. 9 (d), the surface of the piezoelectric ceramic plate 121 opposite to the surface on which the groove 122 is formed is ground or polished by grinding or polishing to completely set the piezoelectric ceramic plate 121 to a predetermined depth. Until it is divided into columns. At this time, the columnar piezoelectric ceramics are securely joined by the epoxy resin.

In the composite piezoelectric body manufactured by joining the two-dimensionally arrayed columnar piezoelectric ceramic elements with epoxy resin, thin-film electrodes are formed on the front and back surfaces by a vapor deposition method, a sputtering method, or the like. . In order to realize an array type ultrasonic transducer, after forming electrodes divided into an array shape on the composite piezoelectric body, a method of forming an acoustic matching layer, a backing material, etc. After forming the acoustic matching layer and the backing material, there is a method of dividing the acoustic matching layer and the electrodes into an array.

[0017]

The FPC used for extracting a signal from an electrode has a limitation in manufacturing the accuracy of a wiring pattern, and the arrangement pitch of ultrasonic transducers in the array direction is small and the number of arrangements is large. In this case, there is a problem that the pitch error of the wiring pattern becomes large, which may adversely affect the accuracy of the array arrangement pitch of the array type piezoelectric body of the ultrasonic transducer. Further, when the array pitch and the number of arrays of the ultrasonic transducers in the array direction exceed the limits in manufacturing the FPC, it becomes difficult to manufacture the FPC or the yield of the FPC is reduced, and the cost of the FPC is reduced. However, there has been a problem that the cost of the supersonic transducer increases accordingly.

Further, when the gap between the wiring patterns of the FPC is narrower than a predetermined width, there is a problem that a preliminary slit cannot be formed and a convex ultrasonic transducer cannot be realized. When a plurality of vibrating elements arranged in an array are formed by dividing the piezoelectric ceramic, the length of the vibrating elements in the slice direction is the same, and the length of the vibrating elements in the array direction (scan direction) is the same.
When the (width) is reduced, the shape of the vibrating element becomes more elongated and rod-shaped, and the strength against impact is reduced, and the vibrating element is likely to be damaged by an impact due to an external force. Therefore, it is necessary to prevent the impact by the external force from affecting the vibration element.

Although an acoustic lens is used in front of the ultrasonic transducer to form a sound field in the slice direction, the acoustic transmission / reception sensitivity is reduced due to acoustic attenuation of the acoustic lens. There was a problem. Especially,
When the focal point of the acoustic lens is set near, there is a problem that the thickness of the acoustic lens is increased, the attenuation is increased, and the transmission / reception sensitivity of the ultrasonic wave is greatly reduced. Also, after forming a thin film electrode on the front and back surfaces of the composite piezoelectric body,
In the case where the thin film electrode is divided for each vibrating element, a part of the thin film electrode is divided in the dividing step because of the small adhesion strength of the thin film electrode to the composite piezoelectric material and the strength of the thin film electrode itself. There is a problem that a defect of peeling off from the substrate and a defect of tearing of the thin film electrode occur.

Further, as described above, since the composite piezoelectric body cannot use a baked silver electrode as an electrode material, an electrode such as a thin film electrode is used, and when a signal line is drawn from the thin film electrode, Since the strength of a thin film electrode such as a thin film electrode is low and the bonding property is poor, bonding by soldering cannot be used, and a conductive adhesive is used. However, since the bonding strength of the conductive adhesive is low, it is necessary to increase the bonding area. Since the portion from which the signal line is drawn from this thin-film electrode (joining portion) is an ineffective portion of vibration, it is necessary to reduce the ineffective portion of vibration in order to improve transmission and reception efficiency. There was a problem that the part had to be made smaller. Further, when a signal line is led out from the thin film electrode, the lead-out portion of the signal line is, for example, as shown in FIG.
Of the piezoelectric material 121 enters the gap between the piezoelectric body 121 and the backing material 126 and becomes a rigid discontinuity point. For example, there is a high possibility that stress due to an external force applied at the time of forming an array by cutting the piezoelectric body is concentrated and damaged. There was a problem of becoming. In addition, similarly, when the leading-out portion is provided on the front surface, there is also a problem in that it becomes a discontinuity point on rigidity, and the possibility of damage due to concentration of stress against external force increases.

An object of the present invention is to provide an ultrasonic transducer capable of extracting a signal line from an electrode of a piezoelectric plate with high accuracy. It is another object of the present invention to provide an ultrasonic transducer capable of preventing a portion of a piezoelectric plate from which a signal line is drawn from an electrode from being damaged.

[0022]

The invention corresponding to claim 1 is:
In an ultrasonic transducer that outputs ultrasonic waves using a piezoelectric body in which N piezoelectric vibrators formed of piezoelectric ceramics are arranged in a line and receives the reflected ultrasonic waves, the ultrasonic output surface of each piezoelectric vibrator And M flexible printed wiring boards on which a total of N wiring patterns arranged in parallel electrically connected to the respective electrodes formed on the surface opposite to the ultrasonic output surface are provided, Each of the flexible printed wiring boards is not divided in the step of dividing the piezoelectric body in manufacturing.

According to a second aspect of the present invention, there is provided an ultrasonic transducer for outputting ultrasonic waves using a piezoelectric body in which N piezoelectric vibrators formed of piezoelectric ceramics are arranged in a line and receiving the reflected ultrasonic waves. In the above, a total of N wiring patterns arranged in parallel electrically connected to the ultrasonic output surface of each piezoelectric vibrator and each electrode formed on the surface opposite to the ultrasonic output surface are formed. A flexible printed wiring board is provided, and each of the wiring patterns formed on the flexible printed wiring board is provided with exposed portions where the conductor is exposed at predetermined intervals.

According to a third aspect of the present invention, in the second aspect of the present invention, each of the piezoelectric vibrators is divided into K pieces in a direction orthogonal to an arrangement direction of the wiring patterns formed on the flexible printed wiring board. At least one exposed portion formed on each wiring pattern of the flexible printed wiring board is formed at a position corresponding to each of the divided parts by filling the gap between these divided parts with a resin. And the respective exposed parts are electrically connected to each other. According to a fourth aspect of the present invention, in the third aspect of the present invention, each piezoelectric vibrator is bent in a direction orthogonal to an arrangement direction of a wiring pattern formed on a flexible printed wiring board, and output from each piezoelectric vibrator. The ultrasonic wave to be focused is focused on a predetermined focal point. According to a fifth aspect of the present invention, in the first aspect of the present invention, the piezoelectric body includes a plurality of columnar piezoelectric ceramics and a resin filled in a gap between these piezoelectric ceramics. And a composite piezoelectric body composed of

According to a sixth aspect of the present invention, an ultrasonic wave is output using a piezoelectric vibrator formed of piezoelectric ceramics,
In an ultrasonic transducer that receives the reflected ultrasonic waves, an ultrasonic output surface of the piezoelectric vibrator and a relay electrode electrically connected to each electrode formed on a surface on the opposite side of the ultrasonic output surface are provided, The relay electrode is electrically connected to an electrode connection portion formed of a conductive material electrically connected to each electrode, and a lead wire for supplying drive power to the piezoelectric vibrator and extracting a reception signal from the piezoelectric vibrator. And a holding member that electrically connects and holds the electrode connection portion and the lead wire connection portion.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the relay electrode is formed on a side surface of the piezoelectric vibrator or on a side surface of the back member formed on a surface opposite to an ultrasonic wave output surface of the piezoelectric vibrator. It is provided in. The invention according to claim 8 is the invention according to any one of claims 6 and 7, wherein the relay electrode is electrically connected to each electrode using a conductive adhesive. The invention corresponding to claim 9 is:
In the invention according to any one of claims 6 and 8, the relay electrode is embedded in the back member on the surface opposite to the ultrasonic wave output surface of the piezoelectric body composed of the piezoelectric vibrator, and is electrically connected to each electrode. The occupation range of the relay electrode on the surface opposite to the ultrasonic output surface of the piezoelectric body is a range extended to the surface on the opposite side of the ultrasonic output surface of the piezoelectric body of the ultrasonic output range. They are restricted so that they do not overlap.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIGS. 1 (a) and 1 (b)
It is the top view and the side view which show the ultrasonic transducer to which this invention is applied. The front (ultrasonic output surface, upper surface) and back (
A baked silver electrode is formed in advance on the surface opposite to the ultrasonic output surface (lower surface), and a plurality of flexible printed wiring boards (hereinafter referred to as FPCs) 2 to 5 are arranged in an array without any gap between the baked silver electrodes. Are electrically connected. Each FPC2
In Nos. 5 to 5, wiring patterns for extracting electrodes of a vibrating element formed by dividing the piezoelectric ceramic plate 1 are formed. The FPCs 2 to 5 are connected to the piezoelectric ceramic plate 1 in such a manner that the wiring patterns are connected to the corresponding positions of the piezoelectric vibrating elements. A part of the FPC 2
The backing material 6 is formed on both sides of the backing material 5.

Both edges of each of the FPCs 2 to 5 are separated from the wiring pattern on the outermost edge so as not to overlap with another FPC when the wiring patterns are aligned and connected to the piezoelectric ceramic plate 1. The dimension up to the outer peripheral edge is defined. That is, at the connection portion with the piezoelectric ceramic plate 1, the distance between the center of the outermost peripheral wiring pattern and the outer periphery of the outermost peripheral line is determined by the array arrangement pitch of the ultrasonic transducer (by dividing the piezoelectric ceramic plate 1). Vibration element arrangement pitch).

The arrangement pitches of the wiring patterns formed on the FPCs 2 to 5 are not the same, and the gap t1 between the outermost arrangement pattern and the adjacent (inner) wiring pattern is different from that of the other (inner) wiring pattern. Array pitch t2
And the gap t3 between the adjacent outermost peripheral wiring patterns of the adjacent FPCs is set to be larger than the arrangement pitch (for example, the arrangement pitch of the vibration elements) when the arrangement pitch of the other wiring patterns is the same. It is.

Each of the FPCs is placed on the piezoelectric ceramic plate 1.
After connecting 2 to 5, the backing material, the acoustic matching layer, and the like are fixed, and finally, along each wiring pattern of the FPCs 2 to 5, as shown in FIG. By dividing the backing material and the like, the ultrasonic transducer is completed. Note that, for simplicity, the acoustic matching layer and the like are omitted in FIG. 1 (b). Further, in order to make the ultrasonic transducer a convex type, it is necessary to connect the ultrasonic transducer to each of the FPs.
After being divided along the wiring patterns C2 to C5, they are bent in a convex shape in the array direction. At this time, each of the F
The PCs 2 to 5 can be compactly folded with good storability as independent convex ultrasonic transducers in independent directions.

As described above, according to the first embodiment, a plurality of the FPCs 2 for drawing out signal lines from the vibrating element formed by dividing the piezoelectric ceramic plate 1 in a block manner.
5, the gap between the outermost peripheral wiring pattern of the FPC and the wiring pattern adjacent thereto is narrower than the arrangement pitch of the other wiring patterns, and the gap between the adjacent outermost peripheral wiring patterns of the adjacent FPC is reduced. By making it larger than the arrangement pitch of the other wiring patterns, it is not necessary to form a slit in the FPC, and it is possible to cope with signal line extraction of the transducer of the ultrasonic transducer having a smaller arrangement pitch with high accuracy. In addition, it can be folded in a compact form with good storability as a convex type.

A second embodiment of the present invention will be described with reference to FIGS. The second embodiment is characterized in that a vibrating element divided into a plurality in the slice direction is used. FIG. 2 is a perspective view showing an ultrasonic transducer to which the present invention is applied, and FIG. 3 is a sectional view in a slice direction of a wiring pattern portion of an FPC showing the ultrasonic transducer. FIG. 2 shows a part of the ultrasonic transducer, and the entire ultrasonic transducer extends in the direction of arrow A. In FIG. 2, the direction of arrow A indicates the array direction of the ultrasonic transducer, and the direction of arrow S indicates the slice direction of the ultrasonic transducer.

Upper surface of the piezoelectric body 12 (front surface = ultrasonic output surface)
The acoustic matching layer 14 is formed on the common electrode 13 formed in (1). Further, a plurality of FPCs 11 electrically fixed to the drive electrodes 15 formed on the lower surface of the piezoelectric body 12 (back surface = surface opposite to the ultrasonic wave output surface) are fixed,
A backing material 16 is fixed to the lower surface of the FPC 11. The piezoelectric body 12 includes a vibrating element 12-1 formed of a piezoelectric ceramic material, and a resin portion 12-2 filled between the vibrating elements 12-1. As shown in FIG. 3, in the wiring pattern of the FPC 11, projecting conductor exposed portions are formed at exactly the same pitch as the arrangement pitch of the piezoelectric elements 12 in the slice direction of the vibrating elements. Is electrically connected to the drive electrode 15 formed on the lower surface of the piezoelectric body 12 and the FP.
It is electrically and reliably connected to the wiring pattern of C11.

FIG. 4 shows the resin section 12-2 in the slice direction.
A plurality of the vibrating elements 12-1 arranged in a row with
FIG. 4 is a diagram showing a state of electrical connection of FIG. That is, a drive signal for driving one channel is supplied from the drive unit 17 to the drive electrode 15 on the lower surface of each of the vibrating elements 12-1 arranged in one row in the slice direction through the wiring pattern of the FPC 11. It has become. This drive signal is independent for each wiring pattern, and the vibrating elements arranged in the slice direction along this wiring pattern are connected as one vibrator in the same signal system, and vibrating elements having different positions in the array direction are provided. The elements are connected by different signal systems.
Also, the common electrode 13 on the upper surface of each of the transducers 12-1 of the ultrasonic transducer is commonly connected to the ground (0).
[V]).

FIG. 5 is a diagram showing a wiring pattern formed on the FPC 11. The FPC 11 has wiring patterns 21-1, 21-2, 21 extending in the slice direction.
-3 and 21-4 are formed, and each of the wiring patterns 21-1 to 21-4 is formed.
On the 21-4, conductor exposed portions 22-1 to 22-8,... Are provided at an arrangement pitch in the slice direction of the vibration element 12-1.
These conductor exposed portions 22-1 to 22-8, ... are two-dimensionally arranged in a matrix.

FIG. 6 is a sectional view showing the conductor exposed portion 22. As shown in FIG. In each of the FPCs 11, a conductor layer 25 for forming a wiring pattern is formed on a base layer 23 by an adhesive 24, and a cover lay 27 made of an insulating material is formed on the conductor layer 25 by an adhesive 26. ing. The conductor exposed portion 22 forms a through hole in the cover lay 27 at a predetermined position on the conductive layer 25, and is electrically connected to the conductor layer 25 so as to pass through the cover lay 27 and cover the cover lay 27. It has a structure protruding from the upper surface.

The method of manufacturing the ultrasonic transducer according to the second embodiment having the above-described structure is applied to the back surface (the surface opposite to the ultrasonic wave output surface, the lower surface in FIG. 3) of the piezoelectric ceramic plate before division. A drive electrode 15 is formed, and the drive electrode 1
5, the FPC 11 is positioned according to the arrangement position of the vibration element in the array direction, and the conductor exposed portions 22 of the respective wiring patterns of the FPC 11 are electrically connected to the drive electrodes 15 respectively, so that each FPC 11 is provided on the back surface of the piezoelectric ceramic plate. Fix it. Examples of the electrical connection method include a method using soldering, a conductive adhesive, and an anisotropic conductive film, and a method using an electrically insulating adhesive to apply pressure to connect.

Next, the back surface (lower surface) of the piezoelectric ceramic plate
The backing material 16 is formed on the back surface of the FPC 11 so as to cover. Next, a plurality of division grooves (grooves extending in the array direction) having a predetermined width for dividing the front surface (the ultrasonic wave output surface, the upper surface in FIG. 2) of the piezoelectric ceramic plate into a plurality in the slice direction are preset. At a pitch (corresponding to an array pitch of the vibration elements in the slice direction). At this time, the division groove may reach the piezoelectric ceramic plate or halfway through the thickness of the piezoelectric ceramic plate so as not to damage the wiring pattern of the FPC 11. Next, a resin is filled in the dividing groove.

Next, a common electrode 13 is formed on the piezoelectric ceramic plate divided in the slice direction and on the front surface of the resin by a thin film forming method such as sputtering or vapor deposition. Next, an acoustic matching layer 14 is formed on the upper surface of the common electrode 13. Next, a plurality (number of channels) in the array direction
A plurality of dividing grooves with a preset width for dividing into
A groove extending in the slice direction is formed at a preset pitch (a pitch corresponding to the array pitch of the vibrating elements in the array direction). The dividing groove may reach the acoustic matching layer 14, the common electrode 13, the piezoelectric ceramic plate divided in the slice direction, and the middle of the thickness of the resin, the FPC 11, and the backing material 16.

As described above, according to the second embodiment, a piezoelectric body (an analog of a composite piezoelectric body) divided into a plurality of pieces in the slice direction and filled with resin in the gaps is used.
The conductor exposed portions 22 protruding from the wiring pattern of the FPC 11 are formed at intervals corresponding to the pitch in the slice direction of the vibration element, and the vibration exposure element and the wiring pattern are connected by the conductor exposed portion 22, thereby ensuring reliable electrical connection. The connection can be performed with high strength, and damage such as disconnection at the drawer can be prevented.

As a result, as compared with the vibrating element formed of one long ceramic, the vibrating element 12-1 formed of short ceramics sandwiching the piezoelectric resin has a higher strength of the vibrating element itself. Moreover, the impact of external force is applied to the resin portion 1.
Since 2-2 is dispersed and absorbed, it is possible to prevent the vibration element 12-1 from being damaged. As shown in FIG. 7, when the number of divisions of the piezoelectric ceramic plate in the slice direction is increased and the width of the vibration element in the slice direction is reduced,
Functioning as a composite piezoelectric body, the electromechanical coupling coefficient can be further increased, and the acoustic impedance of the piezoelectric body can be further reduced.

A third embodiment of the present invention will be described with reference to FIG. The ultrasonic transducer according to the third embodiment has basically the same configuration as that of the above-described second embodiment, but has a different shape in the slice direction. There is a feature. FIG. 8 is a sectional view in the slice direction showing an ultrasonic transducer to which the present invention is applied. An acoustic matching layer 23 is formed on the common electrode 22 formed on the upper surface (front surface = output surface of ultrasonic waves) of the piezoelectric member 21 bent in the slice direction into a substantially concave lens shape.
Are formed along the bent shape of. Further, the FPC 2 electrically connected to the drive electrode 24 formed on the lower surface of the piezoelectric body 21 (back surface = surface opposite to the ultrasonic wave output surface)
5 is fixed, and a backing material 2
6 is fixed. The piezoelectric body 21 includes a vibration element 21-1 formed of a piezoelectric ceramic material, and a resin portion 21-2 filled between the vibration elements 21-1. The state of the electrical connection of the plurality of vibrating elements and the configuration of the wiring pattern and the exposed conductor on each of the FPCs 25 are described in the second embodiment (see FIGS. 4 to 6).
), The description is omitted here.

In the method of manufacturing the ultrasonic transducer according to the third embodiment having such a structure, the drive electrode 24 is formed on the back surface (the surface opposite to the ultrasonic wave output surface) of the piezoelectric ceramic plate before the division. Then, the FPC 25 is positioned on the drive electrode 24 in accordance with the arrangement position of the vibration element in the array direction, and the conductor exposed portions of the respective wiring patterns of the FPC 25 are electrically connected to the drive electrode 24, respectively.
Is fixed to the back of the piezoelectric ceramic plate. Next, a plurality of division grooves (grooves extending in the array direction) having a predetermined width for dividing the front surface (output surface of ultrasonic waves) of the piezoelectric ceramic plate into a plurality of pieces in the slice direction are set at a predetermined pitch (vibration). At a pitch corresponding to the arrangement pitch of the elements in the slice direction). At this time, this dividing groove is
The wiring pattern 5 is made to reach the piezoelectric ceramic plate without being damaged.

Next, all the FPCs 25 to which the piezoelectric ceramic plates divided in the slice direction are fixed are bent in the slice direction into substantially concave lens shapes. Next, a backing material 26 is formed so as to cover the back surface of each FPC 25 in the bent state. Next, a resin is filled in the dividing groove. Next, a common electrode 22 is formed on the piezoelectric ceramic plate divided in the slice direction and on the front surface of the resin by a thin film forming method such as sputtering or vapor deposition. Next, an acoustic matching layer 23 is formed on the upper surface of the common electrode 22.

Next, a plurality of division grooves having a predetermined width for dividing into a plurality (the number of channels) in the array direction are set at a predetermined pitch (a pitch corresponding to the arrangement pitch of the vibrating elements in the array direction). ). The dividing groove may reach the acoustic matching layer 23, the common electrode 22, the piezoelectric ceramic plate divided into a plurality in the slice direction, and the middle of the thickness of the resin, the FPC 25 and the backing material 26. Further, on the front surface of the acoustic matching layer 23, a protective coating (protective layer) may be formed of a material having a low attenuation of ultrasonic waves in consideration of the contact with the surface of the imaging target. Alternatively, the concave portion on the front surface of the acoustic matching layer 23 having a substantially concave lens shape may be filled with a protective layer to form a flat shape as the front surface of the ultrasonic transducer.

As described above, according to the third embodiment, it is possible to obtain the effects of the second embodiment described above and to form a vibrating element bent in the slice direction. If the bent shape is properly selected so that the beam converges to form a focal point, a sound field can be formed in the slice direction without using a conventional acoustic lens, and there is no attenuation of ultrasonic waves by the acoustic lens, Sound wave sensitivity can be improved. In this embodiment, as a method of manufacturing the ultrasonic transducer, the FP is attached to the piezoelectric ceramic plate.
Immediately after the C25 is fixed, the piezoelectric ceramic plate is divided into a plurality of pieces in the slice direction, bent into a substantially concave lens shape, and the method of forming the backing material after bending is described. However, the present invention is not limited to this. Not something
After fixing the FPC25 to the piezoelectric ceramic plate,
After forming a backing material (thin backing material) and other members suitable for bending to the back of 25, the piezoelectric ceramic plate is divided into a plurality in the slice direction,
It may be bent into a substantially concave lens shape.

A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a sectional view in the slice direction showing an ultrasonic transducer to which the present invention is applied. The composite piezoelectric body 31 is, for example, as shown in FIG. 7 or FIG.
It is as shown in. The upper surface of the composite piezoelectric body 31 (
Front = output surface of ultrasonic wave) On the common electrode 32 of a metal thin film
A drive electrode 33 of a metal thin film is provided on the lower surface (rear surface = surface opposite to the ultrasonic wave output surface) for each vibration element (not shown) constituting the composite piezoelectric body 31. Is formed. Although an example in which a metal thin film is used as an electrode will be described here, a conductive resin may be used. However, a baked silver electrode cannot be used in the composite piezoelectric body 31.

The common electrode 32 is routed in the slicing direction to the lower surface of the composite piezoelectric body 31, and the drive electrode 33 is separated from the common electrode 32 to the upper surface of the composite piezoelectric body 31. It is routed in the slice direction from the opposite side. On the upper surface of the common electrode 32, an acoustic matching layer 34 is formed with a reduced width in the slice direction so as not to cover both end portions (the common electrode and the extended drive electrode remain exposed). A backing material 35 is formed on the lower surface of the drive electrode 33 and the lower surface of the routed portion of the common electrode 32, that is, over the entire lower surface of the composite piezoelectric body 31.

A portion extending to the lower surface of the common electrode 32 (exposed portion) and a portion extending to the upper surface of the drive electrode 33 (exposed portion) are led out by conductive paste (or conductive adhesive) 36, 37. Substrates 38 and 39 are electrically and mechanically connected. Each drawer substrate 3
8, 39, the common electrode 32 and the drive electrode 33
The electrode layers 38-1 and 39-1 corresponding to the shape of the substrate are formed so as to go around the surfaces of the side surfaces of the extraction substrates 38 and 39, and the common electrode 3 of the extraction substrates 38 and 39 is formed.
2 or when the portion connected to the drive electrode 33 is on the inside, the electrode layers 38-1,
Part or all of the outer portion of 39-1 is formed by a baked silver electrode. The ground silver plate for drawing out the ground wire and the signal FPC 41 for drawing out the signal line are provided on the baked silver electrodes of the drawing substrates 38 and 39, respectively.
Are connected by soldering or the like.

In the fourth embodiment having such a structure, the common electrode 32 having a low strength of the thin film of the composite piezoelectric body 31 is used.
And the drive electrode 33 are each provided with a high-strength extraction substrate 3.
After being pulled out to the electrode layers 38-1 and 39-1 of 8, 39 once,
It is drawn out to each wiring pattern of FPCs 40 and 41 soldered to burnt silver electrodes formed on the electrode layers 38-1 and 39-1. As described above, according to the fourth embodiment, the extraction of the signal lines and the ground lines of the electrodes 32 and 33 of the composite piezoelectric body 31 is performed via the extraction substrates 38 and 39.
0, 41, the shapes of the electrode layers 38-1, 39-1 of the lead-out substrates 38, 39 can be adjusted by the common electrode 32 of the composite piezoelectric body 31 and the drive without being restricted by the wiring patterns of the FPCs 40, 41. By matching the shape of the electrode 33,
A sufficient electric connection area and a free connection posture can be obtained, and the FPCs 40 and 41 are connected to the baked silver electrodes of the extraction substrates 38 and 39 by soldering. 32,33 and FPC40,4
1 can be electrically connected with high strength.

Further, the FPCs 40 and 41 are connected to the drawing substrate 3.
Since the connection position and connection posture of the FPCs 40 and 41 can be freely selected by connecting to the electrodes 32 and 33 of the composite piezoelectric body 31 via the electrodes 8 and 39, the conventional FPC needs to be bent. In addition, the selectivity of the shape of the ultrasonic transducer is increased, miniaturization can be realized, and a convex ultrasonic transducer can be supported. Further, the backing material 35 can be formed on the entire back surface of the composite piezoelectric body 31, there is no discontinuity in rigidity, and the stress to the external force applied at the time of forming the array by cutting (dividing) is dispersed and damaged. Can be obtained. Also,
Since the extraction substrates 38 and 39 cover side edges of the composite piezoelectric body 31 in the slice direction, an effect of protecting the composite piezoelectric body 31 can be obtained.

A modification of the fourth embodiment is shown in FIGS. FIG. 10 is a cross-sectional view in the slice direction showing an ultrasonic transducer according to a first modification. On the upper surface of the composite piezoelectric body 51, a common electrode 52 of a metal thin film is formed, and on the lower surface thereof, a driving electrode 53 of a metal thin film is provided with each vibration element (not shown) constituting the composite piezoelectric body 51.
It is formed every time. The common electrode 52 is routed in the slice direction to the lower surface of the composite piezoelectric body 51, and the drive electrode 53 is connected to the composite piezoelectric body 51.
Are drawn in the slice direction from the side opposite to the common electrode 52 up to the upper surface of.

An acoustic matching layer 54 is formed on the upper surface of the common electrode 52 and the upper surface of the extended portion of the drive electrode 53, that is, over the entire upper surface of the composite piezoelectric body 51. The lower surface of the end portion (the end portion on the side routed to the upper surface) and the lower surface of the portion routed to the lower surface of the common electrode 52 respectively have a conductive paste (
Or a conductive adhesive) 55, 56 to draw out the substrate 57,
The upper surface of 58 is electrically and mechanically connected. A backing material 59 is formed on the lower surface of the composite piezoelectric body 51 (drive electrode 53) between the drawing substrates 57 and 58 and over the lower surface. That is, the drawing substrates 57 and 58 are embedded in the backing material 59 to form an integral type.

On the drawing substrates 57 and 58, electrode layers 57-1 and 58-1 having a shape corresponding to the shape and arrangement of the common electrode 52 and the driving electrode 53 are provided.
8 is formed so as to make a circuit around the surface of the side surface, and at least a part or all of the surfaces of the respective draw-out substrates 57 and 58 that are not covered with the backing material 59 are formed by baked silver electrodes. . Each of the drawing substrates 57 and 5
The ground silver 60 for drawing out the ground wire and the signal FP for drawing out the signal line are connected to the baked silver electrode 8 respectively.
The wiring pattern of C61 is connected by soldering or the like. As described above, according to this modification, the drawing substrate 57,
Since the draw-out substrates 57 and 58 are integrated with the backing material 59 so that the entirety of the 58 is completely housed in the backing material 59, there is no discontinuity in rigidity, and cutting (division) is performed.
As a result, the effect of dispersing the stress to the external force applied at the time of forming an array by the method can be obtained, and the effect of reducing the size can be obtained.

FIG. 11 is a sectional view in the slice direction showing an ultrasonic transducer according to a second modification. On the upper surface of the composite piezoelectric body 71, a common electrode 72 of a metal thin film is formed, and on the lower surface thereof, a drive electrode 73 of a metal thin film is provided for each vibration element (not shown) constituting the composite piezoelectric body 71. Is formed. The common electrode 72 is routed in the slice direction to the lower surface of the composite piezoelectric body 1,
Further, the drive electrode 73 is extended in the slice direction from the opposite side to the common electrode 72 up to the upper surface of the composite piezoelectric body 71.

An acoustic matching layer 74 is formed on the upper surface of the common electrode 72 and the upper surface of the routed portion of the drive electrode 73, that is, over the entire upper surface of the composite piezoelectric body 71. The lower surface of the end (the end on the side routed to the upper surface) and the lower surface of the portion routed to the lower surface of the common electrode 72 are each provided with a conductive paste (
Or a conductive adhesive) 75, 76 to draw out the substrate 77,
78 is electrically and mechanically connected to the upper surface. A backing material 79 is formed between the extraction substrates 77 and 78 on the lower surface of the composite piezoelectric body 71 (drive electrode 73).
Unlike the above-described modification, the backing material 79 is not formed on the lower surfaces of the draw-out substrates 77 and 78.

The extraction substrates 77 and 78 are provided with electrode layers 77-1 and 78-1 having a shape corresponding to the shape and arrangement of the common electrode 72 and the drive electrode 73, respectively.
A portion or the entire surface of each of the drawing substrates 77 and 78 that is not covered with the backing material 79 is formed by a baked silver electrode. The wiring patterns of an earth plate 80 for extracting an earth line and a signal printed circuit board (signal PC) 81 for extracting a signal line are respectively connected to the baked silver electrodes of the extraction substrates 78 and 79 by soldering or the like. It is connected. Each printed circuit board (PC) 80, 81
Has significantly higher mechanical strength than the above-described FPC, and has a strength equal to or higher than that of the backing material 79.

In the fourth embodiment described with reference to FIGS. 9 to 11, the drawing substrates 38, 39, 57, 5
8, 77, 78 are formed of ceramics having high strength and good workability, and have electrode layers 38-1, 39-1, 57-1, 5-5.
8-1, 77-1 and 78-1 are constituted by baked silver electrodes. For this reason, the substrate for extraction and the piezoelectric body are not damaged without applying (concentrating) stress to an external force applied when forming the array by cutting (dividing) the piezoelectric body into the array. Will be retained.

The material of the drawing substrate is not limited to ceramics, but may be glass epoxy resin or the like. In particular, in the example shown in FIG. 9, the length in the thickness direction of the composite piezoelectric body 31 on the surface connecting the FPC and the ground plate of the drawing substrate (
Height) when cutting the piezoelectric body to form an array,
The draw-out board is also short enough to be divided and long enough to prevent trouble when connecting the FPC and the ground plate. That is, the length is 1.5 times or more and 4 times or less the thickness of the decoding piezoelectric body 31.

In the example shown in FIG. 10, the length (height) in the thickness direction of the decoding piezoelectric body 51 on the surface connecting the FPC and the ground plate of the drawing substrate is formed by cutting the piezoelectric body. In this case, the drawer board is also short enough to be divided and long enough to prevent trouble when connecting the FPC and the ground plate. That is, the length is at least one and three times the thickness of the decoding piezoelectric body 51.

Further, in the example shown in FIG. 11, the length (height) in the thickness direction of the decoding piezoelectric body 71 on the surface connecting the FPC and the ground plate of the drawing board is formed by cutting the piezoelectric body to form an array. In this case, the drawer board is also short enough to be divided and long enough to prevent trouble when connecting the FPC and the ground plate. That is, the length is three times or less the thickness of the decoding piezoelectric body 71.

As described above, according to this modification, in addition to the effects of the above-described modification, the cross-sectional area of the ultrasonic transducer can be made substantially equal to the cross-sectional area of the back surface of the piezoelectric body. Incorporation into thin probes becomes possible. Although the fourth embodiment and its two modifications have been described with respect to an example in which a composite piezoelectric body is used, the present invention is not limited to this, and one embodiment that is not divided in the slice direction is used. The vibrating elements are arranged and a plurality of piezoelectric elements are arranged in the array direction. Although two modified examples are shown here, the present invention is based on the idea that the FPC is electrically connected to the electrodes of the piezoelectric body through an intermediary member such as a drawer board. Various modifications are possible within a range not to do.

[0063]

As described in detail above, according to the present invention,
An ultrasonic transducer capable of extracting a signal line from an electrode of a piezoelectric plate with high accuracy can be provided. In addition, it is possible to provide an ultrasonic transducer that can draw out a signal line from the electrode of the piezoelectric plate with high accuracy and that can prevent damage to the drawn-out portion.

[Brief description of the drawings]

FIG. 1 is a top view and a side view showing an ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an ultrasonic transducer according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view in the slice direction of a wiring pattern portion of the FPC showing the ultrasonic transducer of the embodiment.

FIG. 4 is an exemplary view showing a state of electrical connection of a plurality of transducers arranged in a slice direction of the ultrasonic transducer according to the embodiment;

FIG. 5 is an FP of the ultrasonic transducer according to the embodiment;
The figure which shows the wiring pattern formed in the upper surface of C.

FIG. 6 is an FP of the ultrasonic transducer according to the embodiment;
Sectional drawing which shows the conductor exposure part of the upper surface of C.

FIG. 7 is a cross-sectional view in the slice direction of a wiring pattern portion of the FPC, showing a modified example of the ultrasonic transducer of the embodiment.

FIG. 8 is a sectional view in the slice direction showing an ultrasonic transducer according to a third embodiment of the present invention.

FIG. 9 is a sectional view in the slice direction showing an ultrasonic transducer according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view in the slice direction showing an ultrasonic transducer according to a first modification of the embodiment.

FIG. 11 is a cross-sectional view in the slice direction showing an ultrasonic transducer according to a second modification of the embodiment.

FIG. 12 is a top view and a side view showing a conventional ultrasonic transducer.

FIG. 13 is a diagram showing a wiring pattern formed on an upper surface of an FPC of a conventional ultrasonic transducer.

FIG. 14 is a top view and a side view showing a conventional array type ultrasonic transducer.

FIG. 15 is a side view in the slice direction showing a state in which a divided substrate of an FPC is folded when manufacturing a conventional convex ultrasonic transducer array.

FIG. 16 is a side view showing a conventional convex ultrasonic transducer array.

FIG. 17 is a sectional view showing a schematic configuration in a slice direction of a conventional electronic scan type ultrasonic transducer.

FIG. 18 is a cross-sectional view in the slice direction showing another conventional ultrasonic transducer.

FIG. 19 is a view showing a manufacturing process of a conventional composite piezoelectric body.

[Explanation of symbols]

1: piezoelectric ceramic plate, 2-5, 11-1, 25, 4
0, 41, 60, 61 ... FPC (flexible printed wiring board), 6, 16, 26, 35, 59, 79 ... backing material, 12, 21, 31, 51, 71 ... composite piezoelectric body,
13, 22, 32, 52, 72 ... common electrode, 14, 2
3, 34, 54, 74: acoustic matching layer, 15, 24, 3
3, 53, 73: drive electrode; 22-1 to 22-8: conductor exposed portion; 38, 39, 57, 58, 77, 78: lead-out board; 80, 81: printed board.

Claims (9)

[Claims] 1. An ultrasonic transducer that outputs ultrasonic waves using a piezoelectric body in which N piezoelectric vibrators formed of piezoelectric ceramics are arranged in a line and receives the reflected ultrasonic waves, M flexible boards in which a total of N wiring patterns arranged in parallel and electrically connected to the ultrasonic output surface of the probe and the respective electrodes formed on the surface opposite to the ultrasonic output surface are formed. An ultrasonic transducer provided with a printed wiring board, wherein each of the flexible printed wiring boards is not divided in a step of dividing a piezoelectric body in manufacturing. 2. An ultrasonic transducer for outputting ultrasonic waves using a piezoelectric body in which N piezoelectric vibrators formed of piezoelectric ceramics are arranged in a line and receiving the reflected ultrasonic waves, A flexible printed wiring board on which a total of N wiring patterns arranged in parallel and electrically connected to the ultrasonic output surface of the child and the respective electrodes formed on the surface opposite to the ultrasonic output surface are formed. An ultrasonic transducer, wherein exposed portions of conductors are exposed at predetermined intervals on each wiring pattern formed on the flexible printed wiring board. 3. The piezoelectric vibrator is divided into K pieces in a direction orthogonal to an arrangement direction of wiring patterns formed on the flexible printed wiring board, and a resin is filled in a gap between these divided pieces. At least one exposed portion formed on each wiring pattern of the flexible printed wiring board is arranged at a position corresponding to each of the divided parts, and each of the divided parts of each of the piezoelectric vibrators and 3. The ultrasonic transducer according to claim 2, wherein the exposed portion is electrically connected. 4. The piezoelectric vibrator is curved in a direction orthogonal to an arrangement direction of a wiring pattern formed on the flexible printed wiring board, and an ultrasonic wave output from each piezoelectric vibrator is focused on a predetermined focal point. The ultrasonic transducer according to claim 3, wherein the ultrasonic transducer is converged. 5. The piezoelectric body according to claim 1, wherein the piezoelectric body is a composite piezoelectric body composed of a plurality of columnar-shaped piezoelectric ceramics and a resin filled in a gap between the piezoelectric ceramics. The ultrasonic transducer according to claim 4. 6. An ultrasonic transducer for outputting an ultrasonic wave using a piezoelectric vibrator formed of piezoelectric ceramics and receiving the reflected ultrasonic wave, comprising: an ultrasonic output surface of the piezoelectric vibrator; Providing a relay electrode electrically connected to each electrode formed on the surface opposite to the output surface, the relay electrode is an electrode connection portion formed of a conductive material electrically connected to each of the electrodes, A lead wire connecting portion formed of a conductive material that supplies driving power to the piezoelectric vibrator and electrically connects a lead wire for drawing out a reception signal from the piezoelectric vibrator; and the electrode connecting portion and the lead wire connection. And a holding member for electrically connecting and holding the parts. 7. The relay electrode is provided on a side surface of the piezoelectric vibrator or on a side surface of a back member formed on a surface of the piezoelectric vibrator opposite to an ultrasonic wave output surface. 7. The ultrasonic transducer according to claim 6. 8. The ultrasonic transducer according to claim 6, wherein the relay electrode is electrically connected to each of the electrodes using a conductive adhesive. 9. The relay electrode, wherein the relay electrode is embedded in the back member on a surface opposite to an ultrasonic wave output surface of the piezoelectric body made of the piezoelectric vibrator and is electrically connected to each of the electrodes. The occupation range of the electrode on the surface opposite to the ultrasonic output surface of the piezoelectric body is limited so as not to overlap the range of the output range of the ultrasonic wave extended to the surface of the piezoelectric body opposite to the ultrasonic output surface. The ultrasonic transducer according to any one of claims 6 and 8, wherein: