JP7670480B2 - Ultrasonic Transducers - Google Patents

Description

The present invention relates to an ultrasonic transducer.

Conventionally, ultrasonic transducers in which a piezoelectric vibrator is disposed within a case are known. For example, the following Patent Document 1 discloses an ultrasonic transducer having a pin-shaped conductive terminal that is electrically connected to an external substrate, and the conductive terminal and the piezoelectric vibrator are connected via a flexible substrate.

Patent No. 5672389

In the ultrasonic transducer described above, the conductive terminals were not held sufficiently, and there was a risk that the conductive terminals would become misaligned relative to the case.

One aspect of the present invention aims to provide an ultrasonic transducer in which the relative positional deviation of the conductive terminals with respect to the case is suppressed.

An ultrasonic transducer according to one embodiment of the present invention is an ultrasonic transducer equipped with a piezoelectric vibrator, and includes a case having a bottom lid, a piezoelectric vibrator arranged on the bottom lid within the case, a holding member held by the case at a position within the case away from the bottom lid, a conductive terminal extending in a direction along the thickness direction of the piezoelectric vibrator and held by the holding member, and a wiring member that electrically connects the piezoelectric vibrator and the conductive terminal within the case.

In the ultrasonic transducer, a holding member that holds the conductive terminal is held in the case. Therefore, the holding member prevents the conductive terminal from shifting relative to the case.

In another embodiment of the ultrasonic transducer, the wiring member is a flexible substrate.

In another embodiment of the ultrasonic transducer, the holding member is held to the case at three or more points when viewed in the thickness direction of the piezoelectric vibrator.

Another embodiment of the ultrasonic transducer further includes a vibration-damping material interposed between the piezoelectric transducer and the holding member in the thickness direction of the piezoelectric transducer, and the wiring member is routed along the surface of the vibration-damping material.

In another embodiment of the ultrasonic transducer, the holding member is made of resin.

According to one aspect of the present invention, an ultrasonic transducer is provided in which the relative positional deviation of the conductive terminals with respect to the case is suppressed.

1 is a schematic perspective view showing an ultrasonic transducer according to an embodiment. 2 is a schematic plan view showing a case and a holding member of the ultrasonic transducer shown in FIG. 1 . FIG. 2 is a schematic perspective view showing an internal configuration of the ultrasonic transducer shown in FIG. 1 . 4 is a cross-sectional view of the ultrasonic transducer shown in FIG. 1 taken along line IV-IV. 1 is a schematic perspective view showing a piezoelectric vibrator having a flexible substrate attached thereto; 1A to 1C are schematic plan views showing ultrasonic transducers of different embodiments. 1 is a schematic perspective view showing an ultrasonic transducer according to a different embodiment. FIG. 8 is a schematic plan view of the ultrasonic transducer shown in FIG. 7. 9 is a cross-sectional view of the ultrasonic transducer shown in FIG. 7 taken along line IX-IX. 1 is a schematic cross-sectional view showing an ultrasonic transducer according to a different embodiment.

Below, an embodiment of the present invention will be described in detail with reference to the attached drawings. In the description, the same elements or elements having the same functions will be denoted by the same reference numerals, and duplicate descriptions will be omitted.

The configuration of the ultrasonic transducer 1 according to the embodiment will be described with reference to Figures 1 to 5.

The ultrasonic transducer 1 can oscillate in response to an electrical signal input from the outside and output an ultrasonic signal. In addition, when the ultrasonic transducer 1 receives an ultrasonic signal from the outside, it can transmit the signal to the outside as an electrical signal.

The ultrasonic transducer 1 has a configuration capable of transmitting and receiving ultrasonic waves, and specifically, has a configuration including a case 10, a piezoelectric vibrator 20 housed within the case 10, a flexible substrate 30, a vibration-damping material 40, and a holding member 50.

The case 10 is a cup-shaped member including a substantially cylindrical tube portion 14 and a bottom cover portion 12 (bottom cover) that closes the bottom opening of the tube portion 14. The case 10 is made of, for example, a metal (aluminum alloy, for example).

A storage space is defined inside the tube portion 14, and the cross-sectional shape of the storage space in a cross section perpendicular to the extension direction of the tube portion 14 is a substantially elliptical ring shape (or a rounded rectangular ring shape). In other words, the storage space has a cross-sectional shape that extends in one direction (the up-down direction in FIG. 2). As shown in FIG. 2, the tube portion 14 has three recesses 15A-15C on the edge of the upper opening. The three recesses 15A-15C are composed of two recesses 15A, 15B and one recess 15C, which are arranged to sandwich the upper opening. The three recesses 15A-15C are designed to have the same depth.

The bottom cover 12 has a generally circular disk shape, and the generally elliptical area that closes the lower opening of the tube 14 is the vibration area V. The vibration area V of the bottom cover 12 has a uniform thickness.

The piezoelectric vibrator 20 is disposed in a vibration region V on the bottom surface 11 of the bottom cover portion 12 of the case 10. As shown in FIG. 5, the piezoelectric vibrator 20 has a rectangular plate-like outer shape. The piezoelectric vibrator 20 is configured to include a piezoelectric layer 21 and a pair of terminal electrodes 22, 23. The upper terminal electrode 22 covers the entire upper surface of the piezoelectric layer 21 except for a part of an uncovered area. In this embodiment, the uncovered area on the upper surface of the piezoelectric layer 21 is provided at the end of the vibration region V in the long axis direction. The lower terminal electrode 23 covers the entire lower surface of the piezoelectric layer 21, covers the upper surface of the piezoelectric layer 21 in the area not covered by the upper terminal electrode 22, and covers the side of the piezoelectric layer 21 so as to connect the lower terminal electrodes 23 covering the upper and lower surfaces of the piezoelectric layer 21. Therefore, the pair of terminal electrodes 22, 23 face each other in the long axis direction of the vibration region V on the upper surface of the piezoelectric layer 21. The piezoelectric layer 21 may be a single-layer structure including one piezoelectric material layer, or a multi-layer structure in which multiple piezoelectric material layers and internal electrode layers are alternately stacked. The piezoelectric material layer may be made of a piezoelectric ceramic material such as PZT. The piezoelectric vibrator 20 may be directly bonded to the bottom cover 12 of the case 10, or may be bonded to the bottom cover 12 of the case 10 via an adhesive such as epoxy resin.

As shown in FIG. 5, the flexible substrate 30 (wiring member) is in the form of a sheet, and one end 30a is arranged so as to be superimposed on the piezoelectric vibrator 20. The flexible substrate 30 is, for example, a flexible printed circuit board (FPC) or a flexible flat cable (FFC). That is, the flexible substrate 30 is a resin sheet made of a resin such as polyimide resin, on which multiple wirings are provided. The flexible substrate 30 electrically connects the terminal electrodes 22, 23 of the piezoelectric vibrator 20 to pin terminals 60A, 60B, which will be described later, through the multiple wirings. Of the multiple wirings provided on the flexible substrate 30, wiring 32 is connected to the upper terminal electrode 22, and wiring 33 is connected to the lower terminal electrode 23.

The damping material 40 is disposed on the piezoelectric vibrator 20. The damping material 40 has, for example, a rectangular parallelepiped shape. An end 30a of the flexible substrate 30 is interposed between the damping material 40 and the piezoelectric vibrator 20. The damping material 40 may be spaced a predetermined distance from the piezoelectric vibrator 20. The damping material 40 can be provided so as to overlap the entire piezoelectric vibrator 20 when viewed in the thickness direction of the piezoelectric vibrator 20. The damping material 40 is, for example, made of a foam (cell structure) mainly made of a thermoplastic resin. The thermoplastic resin includes, for example, ethylene propylene diene rubber (EPDM).

As shown in FIG. 4, the flexible substrate 30 is routed along the surface of the vibration-damping material 40. Specifically, the flexible substrate 30 is pulled out from the bottom side of the vibration-damping material 40 through the side surface to the top side. Therefore, one end 30a of the flexible substrate 30 is located on the bottom side of the vibration-damping material 40, and the other end 30b is located on the top side of the vibration-damping material 40.

A pair of pin terminals (conductive terminals) 60A, 60B are connected to the end 30b of the flexible substrate 30. The pair of pin terminals 60A, 60B are electrically connected to an external substrate (not shown), and signals are transmitted and received between the external substrate and the ultrasonic transducer 1 via the pair of pin terminals 60A, 60B. Both of the pair of pin terminals 60A, 60B extend along the thickness direction of the piezoelectric vibrator 20. The lower end 60a of each pin terminal 60A, 60B is electrically connected to the end 30b of the flexible substrate 30 standing on the upper side of the vibration damping material 40. More specifically, the lower end 60a of one pin terminal 60A is connected to the wiring 32 provided on the flexible substrate 30, and the lower end 60a of the other pin terminal 60B is connected to the wiring 33. The lower end 60a of the pin terminals 60A, 60B and the wiring 32, 33 of the flexible substrate 30 can be connected, for example, by soldering.

The holding member 50 holds a pair of pin terminals 60A, 60B against the case 10. The holding member 50 is located above the vibration-damping material 40 and is spaced apart from the bottom cover 12 of the case 10. The holding member 50 is configured with a main body 52 and three legs 54A, 54B, 54C. The holding member 50 is configured, for example, from a resin (PBT resin as one example). The holding member 50 is not limited to PBT resin, but may be PPS resin, ABS resin, etc., and may contain glass fiber.

The main body 52 is a portion that extends along the thickness direction of the piezoelectric vibrator 20, and has a rectangular parallelepiped outer shape. The main body 52 is located near the upper opening of the case 10. A pair of pin terminals 60A, 60B are attached to the main body 52. Specifically, the pair of pin terminals 60A, 60B penetrate the main body 52, and the lower end 60a is exposed from the main body 52. The pair of pin terminals 60A, 60B are aligned in parallel with each other in the long axis direction of the vibration region V, and are attached to the main body 52 with a predetermined distance between them.

All three legs 54A, 54B, and 54C are integral with the main body 52 and extend from the main body 52 in a direction perpendicular to the thickness direction of the piezoelectric vibrator 20. Of the three legs 54A, 54B, and 54C, two legs 54A and 54B have elongated shapes extending along the short axis direction of the vibration region V and are parallel to each other. The ends 54a of each leg 54A and 54B enter the recesses 15A and 15B of the case 10 and are supported from below by the tube portion 14 of the case 10. The leg 54C also extends along the short axis direction of the vibration region V like the legs 54A and 54B, but the leg 54C extends on the opposite side of the main body 52 to the legs 54A and 54B. Leg 54C is designed to be shorter than legs 54A and 54B, fits entirely into recess 15C of case 10, and is supported from below by tube 14 of case 10.

As shown in FIG. 2, recess 15C of case 10 and leg 54C of holding member 50 are located approximately midway in the long axis direction of vibration region V, and are offset from legs 54A and 54B by approximately the same distance in the long axis direction of vibration region V. Therefore, the positional relationship of the three points at which legs 54A to 54C are supported by case 10 (i.e., the three locations at which recesses 15A to 15C are provided) is that of an isosceles triangle with the point at which leg 54C is supported as a vertex.

The holding member 50 is attached to the case 10 by pressing each of the legs 54A-54C of the holding member 50 into the recesses 15A-15C. By designing the recesses 15A-15C to be the same depth, the height positions of the legs 54A-54C (for example, the height position relative to the bottom surface 11) become the same, and the posture of the holding member 50 becomes stable. When the holding member 50 is attached to the case 10, the pin terminals 60A, 60B extend in the thickness direction of the piezoelectric vibrator 20.

The pin terminals 60A and 60B can be attached to the holding member 50 before the holding member 50 is attached to the case 10. The pin terminals 60A and 60B are attached to the holding member 50 by, for example, insert molding.

The storage space of the case 10 is filled with a filler 70. The filler 70 is filled after the holding member 50 is attached to the case 10, and the gaps in the storage space are filled with the filler 70. As shown in FIG. 1, a part of the main body 52 of the holding member 50 is located above the upper opening of the case 10 and is exposed from the filler 70. The filler 70 can be made of urethane, for example. Note that the filler 70 is omitted from the plan view of FIG. 2 and the cross-sectional view of FIG. 4 to make the internal configuration easier to see.

The piezoelectric vibrator 20 vibrates in response to signals input from pin terminals 60A and 60B. When the piezoelectric vibrator 20 vibrates, mechanical vibrations with ultrasonic periods are generated in the plate thickness direction, and ultrasonic vibrations are generated in the plate thickness direction and in a direction perpendicular to the plate thickness direction. As the piezoelectric vibrator 20 vibrates ultrasonically, the vibration region V of the bottom cover 12 of the case 10 also vibrates ultrasonically, and ultrasonic waves are output from the bottom cover 12 side to the outside of the case.

As described above, the ultrasonic transducer 1 includes a case 10 having a bottom cover 12, a piezoelectric vibrator 20 disposed on the bottom cover 12 within the case 10, a holding member 50 held by the case 10 at a position separated from the bottom cover 12 within the case 10, pin terminals 60A, 60B extending in a thickness direction of the piezoelectric vibrator 20 and held by the holding member 50, and a flexible substrate 30 electrically connecting the piezoelectric vibrator 20 and the pin terminals 60A, 60B within the case 10.

That is, in the ultrasonic transducer 1, the holding member 50 that holds the pin terminals 60A and 60B is held directly by the case 10. The holding member 50 can suppress misalignment of the pin terminals 60A and 60B relative to the case 10. In particular, the holding member 50 is press-fitted into the recesses 15A to 15C of the case 10, and is therefore firmly fixed to the case 10. Therefore, the holding member 50 is less likely to misalign relative to the case 10, and as a result, misalignment of the pin terminals 60A and 60B relative to the case 10 is more effectively suppressed. Note that the holding member 50 may be held to the case 10 by adhesion, instead of by press-fitting.

In the above embodiment, the holding member 50 is supported on the case 10 at three points, and the three-point support effectively prevents the pin terminals 60A, 60B from shifting relative to the case 10. However, the holding member 50 may be supported on the case 10 at one point, two points, or four or more points.

Figures 6 to 10 show an embodiment in which the holding member 50 is supported by the case 10 at one point. In the embodiment shown in Figure 6, the leg 54C of the holding member 50 is supported by the recessed portion 15C of the case 10, the other legs 54A and 54B are not supported by the case 10, and the ends 54a of the legs 54A and 54B abut the inner surface of the tube portion 14 of the case 10. According to this embodiment, the legs 54A and 54B abutting the inner surface of the tube portion 14 exert a force in a direction that pushes the leg 54C toward the recessed portion 15C, and the relative positional deviation of the pin terminals 60A and 60B in the minor axis direction of the vibration region V is particularly suppressed. In the embodiment shown in Figures 7 to 10, the holding member 50 has only the leg 54C, and does not have the above-mentioned legs 54A and 54B. According to this embodiment, the holding member 50 is held in the case 10 simply by pressing the leg 54C into the recess 15C, so the force required for pressing is smaller and workability is improved compared to an embodiment in which the holding member 50 is supported at three points. In all of the embodiments shown in Figures 6 to 10, the holding member 50 can prevent the pin terminals 60A and 60B from shifting relative to the case 10.

The shapes of the pin terminals 60A, 60B and the connection between the pin terminals 60A, 60B and the flexible substrate 30 are different between the embodiment shown in FIG. 7 to FIG. 9 and the embodiment shown in FIG. 10. In the embodiment shown in FIG. 7 to FIG. 9, the lower ends 60a of the pin terminals 60A, 60B are bent at a right angle to the same side. They are electrically connected to the end 30a of the flexible substrate 30 that extends parallel to the lower ends 60a of the pin terminals 60A, 60B. In the embodiment shown in FIG. 10, the lower end 60a extending along the thickness direction of the piezoelectric vibrator 20 is electrically connected to the end 30b of the flexible substrate 30 that stands up on the upper side of the vibration-damping material 40, as in the embodiment shown in FIG. 4. According to this embodiment, the distance between the ends 30a, 30b of the flexible substrate 30 can be increased in the thickness direction of the piezoelectric vibrator 20, so that a larger vibration-damping material 40 can be used.

Although the preferred embodiment of the present invention has been described above, the present invention is not necessarily limited to the above-mentioned embodiment, and various modifications are possible without departing from the gist of the present invention. For example, the wiring member is not limited to a flexible substrate, but may be a lead frame or a lead wire. Furthermore, the piezoelectric vibrator is not limited to a rectangular plate shape, but may be, for example, a circular plate shape or an elliptical plate shape.

1 ultrasonic transducer, 10 case, 12 bottom cover portion, 14 cylinder portion, 20 piezoelectric vibrator, 30 flexible substrate, 40 vibration damping material, 50 holding member, 60A, 60B pin terminals.

Claims (10)

An ultrasonic transducer having a piezoelectric vibrator,
a case having a bottom cover;
a piezoelectric vibrator disposed on the bottom cover within the case;
a holding member held directly by the case at a position spaced apart from the bottom cover within the case;
a conductive terminal extending in a thickness direction of the piezoelectric vibrator and held by the holding member;
a wiring member that electrically connects the piezoelectric vibrator and the conductive terminal within the case;
Equipped with
The wiring member is a flexible substrate,
The holding member includes a main body and a leg portion integrally formed with the main body,
the case has a recess into which the leg of the holding member fits,
An ultrasonic transducer, wherein the holding member is held by the case at the position of the legs when viewed in the thickness direction of the piezoelectric vibrator. The holding member has three or more of the legs,
the case has three or more recesses into which the legs of the holding member fit,
2. The ultrasonic transducer according to claim 1 , wherein the holding member is held by the case at three or more points when viewed in a thickness direction of the piezoelectric vibrator. a vibration-damping material interposed between the piezoelectric vibrator and the holding member in a thickness direction of the piezoelectric vibrator;
3. The ultrasonic transducer according to claim 1 , wherein the wiring member is routed along a surface of the vibration-damping material. The ultrasonic transducer according to any one of claims 1 to 3 , wherein the holding member is made of resin. An ultrasonic transducer having a piezoelectric vibrator,
a case having a bottom cover;
a piezoelectric vibrator disposed on the bottom cover within the case;
a holding member held by the case at a position spaced apart from the bottom cover within the case;
a conductive terminal extending in a thickness direction of the piezoelectric vibrator and held by the holding member;
a wiring member that electrically connects the piezoelectric vibrator and the conductive terminal within the case,
The holding member includes a main body and a leg portion integrally formed with the main body,
the case has a recess into which the leg of the holding member fits,
An ultrasonic transducer, wherein the holding member is held by the case at the position of the legs when viewed in the thickness direction of the piezoelectric vibrator. The holding member has three or more of the legs,
the case has three or more recesses into which the legs of the holding member fit,
6. The ultrasonic transducer according to claim 5 , wherein the holding member is held by the case at three or more points when viewed in a thickness direction of the piezoelectric vibrator. 7. The ultrasonic transducer according to claim 5 , wherein the main body of the holding member extends along a thickness direction of the piezoelectric vibrator. The ultrasonic transducer according to claim 5 , wherein the legs of the holding member extend in a direction perpendicular to a thickness direction of the piezoelectric vibrator. a vibration-damping material interposed between the piezoelectric vibrator and the holding member in a thickness direction of the piezoelectric vibrator;
The ultrasonic transducer according to claim 5 , wherein the wiring member is routed along a surface of the vibration-damping material. The ultrasonic transducer according to claim 5 , wherein the holding member is made of resin.

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