JP2012034019A - Ultrasonic transceiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive ultrasonic transceiver having a high sound pressure where the number of components is decreased, a plurality of ultrasonic transceivers can be manufactured simultaneously on one substrate, and individual ultrasonic transceivers can be mounted on the substrate and demounted therefrom easily.SOLUTION: An ultrasonic transceiver unit is formed by bonding a diaphragm 8 having a terminal on the outer periphery to a piezoelectric element 3. Because of the geometrical features of the bent terminal, the diaphragm 8 oscillates easily to generate an ultrasonic wave of high sound pressure without preventing oscillation of the piezoelectric element. The tip of the terminal of the diaphragm is soldered to a substrate 9.

Description

The present invention relates to an aerial ultrasonic transmitter / receiver in which a piezoelectric element is bonded to a metal plate.

A unimorph vibrator is formed by bonding a piezoelectric element provided with double-sided electrodes to a disk-shaped plate made of metal. By applying a pulse voltage having the same frequency as the natural frequency of the unimorph vibrator to the electrodes provided on both surfaces of the piezoelectric element, the unimorph vibrator performs bending vibration and generates ultrasonic waves.

As an open-type ultrasonic transmitter / receiver, a simple structure in which a piezoelectric element with a double-sided electrode is bonded to a disk-shaped metal plate made of metal, and a lead wire is soldered to the electrode, and a disk-shaped metal plate A structure in which a piezoelectric element is bonded to a conical resonator on a metal plate is widely used. In addition, an ultrasonic transmitter / receiver has been developed in which a disc-shaped (cymbal) metal plate with a concave center is bonded to both surfaces of a piezoelectric element provided with a double-sided electrode, and a lead wire is soldered to the double-sided electrode.

FIG. 1 shows an example of an open-type ultrasonic transceiver in which a conical resonator is attached on a metal plate.
A disc-shaped piezoelectric element 3 to which double-sided electrodes are attached is bonded to a disc-shaped diaphragm 2 made of metal with an adhesive. A conical resonator 1 made of metal is attached on a metal plate 2 by an adhesive. The piezoelectric element 3 and the mold 5 are bonded so as to float the piezoelectric element 3 from the molding 5 with low hardness silicone. Lead wires 4 are soldered to both surfaces of the piezoelectric element 3. One end of the lead wire 4 is soldered to the electrode pin 6 of the mold 5. Bending vibration generated by the piezoelectric element 3 and the metal plate 2 is amplified by the conical resonator 1. Compared with the case where the resonator 1 is not provided, a large sound pressure and sensitivity can be obtained.

FIG. 2 shows an example of an ultrasonic transceiver in which a cymbal metal plate is bonded. Two discs 7 made of metal and recessed at the center are bonded to both surfaces of a disk-like piezoelectric element 3 having the same outer diameter as the disk 7 so that the recessed side is on the piezoelectric element side.
Lead wires 4 are soldered to the double-sided electrodes of the piezoelectric element 3. The expansion and contraction of the piezoelectric element 3 is amplified by the shape characteristics of the two disks 7, and a high sound pressure can be obtained as compared with an ultrasonic transceiver having a simple unimorph structure.

Airborne ultrasonic transmitters / receivers have been widely used for distance meters or object detection. Recently, a speaker having directivity (parametric speaker) using the characteristics of ultrasonic waves has been actively developed. As an ultrasonic transmitter / receiver for a parametric speaker, an ultrasonic transmitter / receiver using a conical resonator is often used. As the sound source of the parametric speaker, since the sound pressure of the ultrasonic transmitter / receiver is low, a plurality of ultrasonic transmitter / receivers of about 10 to 100 are used side by side. In addition, since ultrasonic waves have a feature that the directivity becomes narrower as the area of the sound source is larger, a plurality of ultrasonic transmitters / receivers are used side by side in order to narrow the directivity. By arranging ultrasonic transmitters / receivers horizontally, a sound source with a large area can be obtained, and sound can be applied only to a narrower range.

Patent Publication 5-153694 Patent Publication 5-328296

Kenji Uchino and Takaaki Ishii “Ferroelectric Devices” Morikita Publishing Co., Ltd. 2005

In terms of performance as a single product, an ultrasonic transmitter / receiver equipped with a conical resonator is superior. However, this structure has a low strength because it is necessary to join parts so as not to disturb the vibration of the piezoelectric element, the metal plate, and the resonator. In addition, the number of parts is large, and the characteristics are affected even with a small load. For this reason, it is difficult to create a plurality of ultrasonic transmitters / receivers on the same substrate. If a problem occurs in an individual ultrasonic transmitter / receiver, create an ultrasonic transmitter / receiver with a cover attached so that the individual ultrasonic transmitter / receiver can be easily removed, and attach it to a large board later. This is common. For this reason, a parametric speaker in which about 100 ultrasonic transmitters / receivers are arranged is very expensive.

There is a need for an ultrasonic transmitter / receiver with high sound pressure that has a small number of parts, can create multiple ultrasonic transmitters / receivers simultaneously on a single board, and can easily attach / detach individual ultrasonic transmitter / receivers to / from the board. It has been.

In the invention according to claim 1,
An ultrasonic transceiver comprising a substrate provided with electrodes, a vibration plate made of metal, a piezoelectric element bonded to the vibration plate, and an electrode provided on the substrate and a lead wire connecting the electrode provided on the piezoelectric element. The vibration plate is at least 1 in a direction (upward or downward) perpendicular to a disk part having a recess in the center of the bonding surface side with the piezoelectric element and at least two or more disks extending from the outer periphery of the disk part. An ultrasonic transmitter / receiver that has a bent end and holds the diaphragm by attaching the tip of the end to the circuit board, so that the sound pressure is high, the number of components is small, and a plurality of parts can be attached at low cost. Is realized.

According to the second aspect of the present invention, an ultrasonic transmitter / receiver having a higher sound pressure is obtained by bonding a disk made of metal and having a recess in the center to a surface opposite to the surface of the piezoelectric element to which the diaphragm is bonded. Is realized.

In invention of Claim 3,
The end of the diaphragm is bent at one of the top and bottom of the disk at a position close to the disk, and further bent in a direction opposite to the direction bent at the end, so that the end is U-shaped or V-shaped. By being processed to become
The diaphragm is easily deformed by the expansion and contraction of the piezoelectric element, and an ultrasonic transmitter / receiver with high sound pressure is realized. Vibration transmission to the substrate can be suppressed, and interference when a plurality of substrates are arranged can be reduced.

In invention of Claim 4, the said piezoelectric element has a double-sided electrode,
The electrode on the surface of the vibration plate and the electrode on the substrate are electrically connected by soldering or bonding the electrode of the substrate with the tip of the spring portion of the vibration plate with an adhesive. The ultrasonic transceiver according to claim 1

According to a fifth aspect of the present invention, the substrate has a plurality of diaphragm mounting portions and a plurality of sound sources to which the plurality of diaphragms are mounted, thereby realizing an inexpensive ultrasonic transceiver for a parametric speaker. To do.

Practical example 1

The Example of this invention is shown. FIG. 3 shows an example of a diaphragm bonded to the piezoelectric element.
Four terminals extend on the outer periphery of a φ8 disk (a disk shaped like a cymbal) with a 2 mm-thick recessed center, and the terminals are bent downward from the disk near the disk. Further, it is bent upward and the tip is bent again. It is bent in a U shape. The vibration plate 8 is formed by punching a metal plate having a thickness of 2 mm into a predetermined shape and pressing it.

FIG. 4 shows an example of a disk bonded to the other surface of the piezoelectric element.
It is in the shape of a φ7.5 disc (cymbal-like disc) with a 2 mm thick recess in the center.
The disk 7 is formed by punching a metal plate having a thickness of 2 mm into a predetermined shape and pressing it.

FIG. 5 shows an assembly drawing. The vibration plate 8 and the disk 7 are bonded to the piezoelectric element 3 having a thickness of φ7.5 and a thickness of 0.2 mm to which double-sided electrodes are applied by an epoxy adhesive. The diaphragm 8 and the electrode of the piezoelectric element 3 are in contact with each other and are electrically connected. The diaphragm 8 is put into a through hole provided in the substrate 9. Independent electrodes are attached to both surfaces of the substrate 9. FIG. 5A shows a disassembled portion and FIG.
The front electrode of the substrate 9 and the tip of the end of the diaphragm 8 are soldered with solder 10, and the lead wire 4 soldered to one surface of the piezoelectric element 3 is soldered to the electrode on the back surface of the substrate 9.
FIG. 6 (a) is a perspective view of the surface of the end of the diaphragm 8 and the surface of the substrate 9 where the electrodes of the substrate 9 are soldered. FIG. 6 (b) is a perspective view as seen from the back side.
By inserting the diaphragm 8 into a hole provided in the substrate 9 and soldering, the ultrasonic transceiver can be easily attached to the substrate 9. Moreover, it can be easily removed.

When a pulse voltage having a frequency that matches the natural vibration of the ultrasonic transmitter / receiver is applied to the electrodes, the vibration surface of the ultrasonic transmitter / receiver vibrates to generate ultrasonic waves.
FIG. 7 shows the vibration state of the ultrasonic transceiver. The piezoelectric element 3 contracts due to the applied voltage, and the diaphragm 8 and the disk 7 are pulled inward by the contracted piezoelectric element 3. Due to the shape characteristics of the diaphragm 8 and the disk 7, the diaphragm 8 and the disk 7 vibrate with the dent portions being greatly deflected. When the diaphragm 8 vibrates up and down, a large ultrasonic wave is generated. At this time, due to the contraction of the piezoelectric element 3, the end portions on the outer periphery of the diaphragm 8 are pulled together. However, the end portion is easily deformed by the U-shaped curve applied to the end portion, and the vibration of the piezoelectric element 3 is efficiently changed to ultrasonic waves without the end portion becoming a large load.

The direction perpendicular to the disk 7 indicates a direction perpendicular to the disk 7 but does not necessarily mean that the terminal of the diaphragm 8 is bent by 90 degrees. It may be 45 degrees or a lower angle. The bending direction of the terminal of the vibration plate 8 may be any direction, but it is desirable to bend it into a spring shape so as not to prevent expansion and contraction of the piezoelectric element 3.

Ultrasonic waves can be transmitted and received without attaching the disk 7 to the piezoelectric element 3. The sound pressure is higher when the disk 7 is bonded.

A metal such as an aluminum alloy or an invar material can be considered as the material of the diaphragm 7. Alternatively, a material obtained by applying nickel plating or the like to a metal to improve solderability may be used.

A plurality of attachment portions can be provided on the substrate 9, and a plurality of ultrasonic transceivers can be attached. Due to the structural features of the diaphragm, the ultrasonic pressure of each ultrasonic transmitter / receiver is large, the ultrasonic transmitter / receiver can be easily attached / detached, the number of parts is small, and an inexpensive ultrasonic transmitter / receiver is realized. FIG. 8 shows an example of an ultrasonic transceiver.

Example of conventional open-type ultrasonic transceiver Example of an ultrasonic transceiver with a conventional cymbal structure Examples of diaphragms embodying the present invention Example of a cymbal disk Example of assembling an ultrasonic transceiver according to the present invention Example of electrode structure for ultrasonic transceiver embodying the present invention State of vibration Ultrasonic transceiver with multiple ultrasonic transceivers

DESCRIPTION OF SYMBOLS 1 Conical resonator 2 Metal plate 3 Piezoelectric element 4 Lead wire 5 Resin mold 6 Metal pin 7 Cymbal type metal plate 8 Vibration plate 9 Substrate 10 Solder

Claims (5)

An ultrasonic transceiver comprising a substrate provided with electrodes, a vibration plate made of metal, a piezoelectric element bonded to the vibration plate, and an electrode provided on the substrate and a lead wire connecting the electrode provided on the piezoelectric element. The vibration plate is at least 1 in a direction (upward or downward) perpendicular to a disk part having a recess in the center of the bonding surface side with the piezoelectric element and at least two or more disks extending from the outer periphery of the disk part. An ultrasonic transmitter / receiver having an end portion of a bent shape and holding a diaphragm by attaching the end of the end portion to a substrate
The ultrasonic transmitter / receiver according to claim 1, wherein a disk made of metal and having a dent in the center is bonded to a surface opposite to a surface of the piezoelectric element to which the diaphragm is bonded.
The end of the diaphragm is bent at one of the top and bottom of the disk at a position close to the disk, and further bent in a direction opposite to the direction bent at the end, so that the end is U-shaped or V-shaped. The ultrasonic transceiver according to claim 1 or 2, wherein the ultrasonic transceiver is processed to be
The piezoelectric element has double-sided electrodes,
The electrode on the surface of the diaphragm of the piezoelectric element and the electrode on the substrate are connected by connecting the tip of the end of the diaphragm to the electrode on the substrate by at least one method of soldering or bonding with an adhesive. The ultrasonic transmitter / receiver according to claim 1, wherein the ultrasonic transmitter / receiver is electrically connected. 5. The ultrasonic transmitter / receiver according to claim 1, wherein the substrate is an ultrasonic transmitter / receiver having a plurality of sound sources and having a plurality of diaphragm mounting portions and having a plurality of diaphragms attached thereto.

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