JP5201087B2 - Transceiver and ultrasonic sensor using the same - Google Patents

Description

  The present invention relates to a transmission / reception apparatus including a piezoelectric element that transmits / receives ultrasonic waves via an acoustic matching member, and an ultrasonic sensor using the transmission / reception apparatus.

  2. Description of the Related Art Conventionally, as a transmission / reception apparatus including a piezoelectric element that transmits and receives ultrasonic waves via an acoustic matching member, a transmission element and a reception element of an ultrasonic sensor shown in Patent Document 1 below are known. The ultrasonic sensor disclosed in Patent Document 1 is attached to a bumper of a vehicle and measures the position of an obstacle in front of the ultrasonic sensor. The transmitting element and the receiving element are acoustically matched to transmit vibration to the piezoelectric element. It is composed of a plurality of sensor elements formed by joining members. At least one of the plurality of sensor elements is used as a transmission element that transmits ultrasonic waves oscillated from the piezoelectric element to the front of the vehicle via the acoustic matching member, and the remainder of the plurality of sensor elements is reflected by the detection target. It functions as a receiving element that receives ultrasonic waves.

JP 2009-58362 A

  By the way, in order to realize the miniaturization of the ultrasonic sensor, for example, it is conceivable that the transmission element and the reception element used as the transmission / reception apparatus are configured by one transmission / reception element and the transmission / reception element is miniaturized. In particular, when the transmitting / receiving element functions as a receiving element, the receiving sensitivity can be improved by reducing the capacitance of the entire receiving element by reducing the number of stacked layers in the piezoelectric element.

  However, when the number of stacked piezoelectric elements is reduced as described above, there is a problem in that when the transmitting / receiving element functions as a transmitting element, the amplitude of the entire transmitting element also decreases, and the transmission sound pressure decreases. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transmission / reception apparatus that can be downsized without deteriorating transmission / reception characteristics and an ultrasonic sensor using the same. There is.

In order to achieve the above object, the transmitting / receiving apparatus according to claim 1 is a transmitting / receiving apparatus including a piezoelectric element that transmits / receives ultrasonic waves via an acoustic matching member, and the piezoelectric element includes a plurality of piezoelectric elements. 1st internal electrode and a plurality of 2nd internal electrodes which are alternately laminated in pairs with a piezoelectric material interposed therebetween, and are joined to the acoustic matching member at one end side in the lamination direction A first receiving external electrode connected to a part of each first internal electrode in the vicinity of the acoustic matching member, and a second internal that forms a pair with a part of each first internal electrode A second receiving external electrode connected to the electrode, a first transmitting external electrode connected to the remaining portion of each of the first internal electrodes, and a pair of the remaining portion of each of the first internal electrodes A second transmission external electrode connected to the second internal electrode, the first reception And the one or more first internal electrodes connected to the first receiving external electrode, the second receiving external electrode, and the second receiving external electrode A receiving unit configured to output an output signal corresponding to the ultrasonic wave received by one or two or more of the second internal electrodes and the piezoelectric bodies interposed between the two internal electrodes; 1 transmission external electrode and the first internal electrodes connected to the first transmission external electrode, the second transmission external electrode and the second transmission external electrode A transmitter configured to transmit the ultrasonic wave corresponding to an input signal input by each of the second internal electrodes and each of the piezoelectric bodies interposed between the two internal electrodes; The cross section perpendicular to the stacking direction of Characterized in that it is gradually larger as apart from the sound matching member.

According to a second aspect of the invention, the transmitting and receiving apparatus according to claim 1, wherein the laminated piezoelectric body, wherein which the second acoustic matching member is joined to the other end in the stacking direction, for the first receiver The external electrode includes a part of one or more of the first internal electrodes in the vicinity of the acoustic matching member and another part of the one or more of the first internal electrodes in the vicinity of the second acoustic matching member. The second receiving external electrode is connected to the second internal electrode paired with the first internal electrode connected to the first receiving external electrode. .

According to a third aspect of the present invention, in the transmission / reception device according to the first or second aspect, the laminated piezoelectric body is formed in a polygonal column shape having a plurality of side surfaces along the laminating direction, and the external electrodes are Each of the side surfaces is provided on each of the side surfaces so that only one of the side surfaces is disposed.

According to a fourth aspect of the present invention, in the transmission / reception device according to the first or second aspect , each external electrode is on a side surface along the laminating direction of the laminated piezoelectric body and is a cross-sectional outer edge perpendicular to the laminating direction. It is provided in a part of.

An ultrasonic sensor according to a fifth aspect includes the transmission / reception device according to any one of the first to fourth aspects, and transmits / receives the ultrasonic wave by the transmission / reception device.

  According to another aspect of the transmission / reception apparatus of the present invention, the piezoelectric element has a laminated piezoelectric body in which a plurality of first internal electrodes and a plurality of second internal electrodes are alternately stacked in pairs with a piezoelectric body interposed therebetween. doing. The receiving unit includes one or more first internal electrodes and one or more second internal electrodes in the vicinity of the acoustic matching member, and each piezoelectric body interposed between the two internal electrodes. And the first receiving external electrode and the second receiving external electrode, and the transmitting unit is interposed between each of the first internal electrode and the remaining part of the second internal electrode, and between these internal electrodes. Each piezoelectric body includes a first transmission external electrode and a second transmission external electrode.

  As described above, since both the reception unit and the transmission unit are configured in one piezoelectric element, the size of the transmission / reception device is reduced as compared with the case where the reception unit and the transmission unit are separately configured by a plurality of piezoelectric elements. can do.

  In particular, when receiving ultrasonic waves, a part of the laminated piezoelectric material is used as the receiver, so compared to the case where all the parts of the laminated piezoelectric material are used as the receiver, the receiving sensitivity is reduced while keeping the capacitance of the receiver small. Can be improved. Furthermore, a large distortion occurs at the joint between the acoustic matching member and the piezoelectric element according to the ultrasonic wave transmitted through the acoustic matching member during reception, so the laminated piezoelectric material near the acoustic matching member is used as the receiver. By doing so, the output voltage from a receiving part becomes large and a receiving sensitivity can be improved.

  In addition, since the portion of the laminated piezoelectric material that does not constitute the receiving unit is configured as the transmitting unit, a large amplitude corresponding to the number of laminated layers is obtained during transmission of ultrasonic waves by the transmitting unit, and ultrasonic waves with higher transmission sound pressure are obtained. Can be sent. Therefore, the transmission / reception apparatus according to the present invention in which the reception unit and the transmission unit are integrally provided in one piezoelectric element has a higher reception sensitivity and transmission sound than the case where the reception unit and the transmission unit are separately configured by a plurality of piezoelectric elements. Miniaturization can be achieved without deteriorating transmission / reception characteristics such as pressure.

  In addition, since the cross section perpendicular to the lamination direction of the laminated piezoelectric body is gradually formed with increasing distance from the acoustic matching member, this shape forms a large cross section perpendicular to the lamination direction in the transmission unit. Thus, a larger driving force can be obtained and an ultrasonic wave having a higher transmission sound pressure can be oscillated. In particular, since the cross section of the laminated piezoelectric body gradually changes, the attenuation of ultrasonic vibration generated in the transmission unit can be reduced as compared with the case where the cross section of the laminated piezoelectric body changes intermittently.
  And since the site | part which adjoins the lamination | stacking direction of a lamination | stacking piezoelectric material is formed relatively small with respect to the site | part which separates from an acoustic matching member, it adjoins to an acoustic matching member. The capacitance of the receiving unit can be further reduced. In addition, since the cross-sectional area of the joint portion between the acoustic matching member and the laminated piezoelectric body is relatively small, distortion generated in the joint portion when receiving ultrasonic waves is further increased, resulting in an increase in output voltage and reception sensitivity. Can be further increased.

In the invention of claim 2 , the second acoustic matching member is joined to the laminated piezoelectric body also on the other end side in the lamination direction, and a receiving portion is also formed in the vicinity of the second acoustic matching member. Thereby, at the time of receiving an ultrasonic wave, an output voltage corresponding to a large distortion generated in the joint portion is output from each receiving unit in the vicinity of both acoustic matching members, so that the signal intensity can be further improved. Note that if each receiving unit is wired using a common wire or the like, the amount of charge in the entire receiving unit increases, so that the signal intensity increases and the influence of disturbance noise can be suppressed, and the S / N can be improved. In addition, it is possible to improve the S / N by individually wiring the receiving units without using a common wire and comparing the ultrasonic signals received by the receiving units.

In the invention of claim 3 , the laminated piezoelectric body is formed in a polygonal column shape having a plurality of side surfaces along the laminating direction, and only one of the external electrodes is arranged with respect to one of the side surfaces. Thus, each is provided on each of the side surfaces. Thereby, since two or more of the external electrodes are not provided on one side surface of the multilayer piezoelectric body, a short circuit between the external electrodes can be reliably prevented. Furthermore, when connecting each internal electrode to the corresponding external electrode, the connection portion of each internal electrode is exposed on the side surface of the laminated piezoelectric body, and this side surface is connected to an internal electrode connected to another external electrode. Since the part is not exposed, it is not necessary to position the exposed position of the connection part of each internal electrode on the side surface with high accuracy, so that the manufacturing work of each internal electrode is facilitated and the manufacturing cost of the transmission / reception device is reduced. Can be reduced.
Even when the laminated piezoelectric body is formed in a substantially cylindrical shape, the same effect can be obtained by partially making only the electrode formation surface flat. When formed in a substantially cylindrical shape, unnecessary vibration can be reduced. Further, by forming only the electrode forming surface partially flat, the electrode formation is facilitated.

According to a fourth aspect of the present invention, each external electrode is provided on a part of the outer edge of the cross section that is on the side surface along the stacking direction of the multilayer piezoelectric body and is orthogonal to the stacking direction. As a result, each external electrode is concentrated and arranged in a predetermined range on the side surface of the laminated piezoelectric material, and therefore the side surface on which each external electrode is not arranged when the transmitter / receiver is accommodated in a housing such as a sensor. There is no need to provide a large insulating space in the vicinity, the space necessary for installing the transmission / reception device in the housing can be reduced, and the size of the sensor using the transmission / reception device can be reduced.

The ultrasonic sensor according to claim 5 includes the transmission / reception device according to any one of claims 1 to 4 , and transmits / receives ultrasonic waves by the transmission / reception device, so that the size can be reduced without deteriorating the transmission / reception characteristics. Thus, it is possible to realize an ultrasonic sensor that enjoys the functions and effects of the inventions of claims 1 to 4 .

It is sectional drawing which shows the structure outline | summary of the ultrasonic sensor 10 which concerns on a 1st reference example . It is a side view which shows one side of the transmission / reception apparatus 20 of FIG. It is sectional drawing which shows the structure outline | summary of the ultrasonic sensor 10a which concerns on the 2nd reference example in 1st Embodiment. It is a sectional view showing a schematic configuration of an ultrasonic sensor 10b that put the first embodiment. It is sectional drawing which shows the structure outline | summary of the ultrasonic sensor 10c which concerns on a 3rd reference example . It is a side view which shows one side of the transmission / reception apparatus 20c of FIG. FIG. 7A is a diagram showing the cross-sectional shape of each internal electrode viewed from the acoustic matching member 21 side in the multilayer piezoelectric body 30 of the ultrasonic sensor 10 according to the fourth reference example , and FIG. 7 (b) shows the first transmission internal electrode 42, FIG. 7 (c) shows the second transmission / reception internal electrode 43, and FIG. 7 (d) shows the second transmission internal electrode 44. Indicates. It is a side view which shows one side of the transmission / reception apparatus 20 in a 4th reference example . FIG. 9A is a diagram showing the cross-sectional shape of each internal electrode viewed from the acoustic matching member 21 side in the laminated piezoelectric body 30 of the ultrasonic sensor 10 according to the fifth reference example , and FIG. 9B shows the first transmission internal electrode 52, FIG. 9C shows the second transmission / reception internal electrode 53, and FIG. 9D shows the second transmission internal electrode 54. Indicates. It is a side view which shows one side of the transmission / reception apparatus 20 in a 5th reference example . FIG. 11A is a diagram showing the cross-sectional shape of each internal electrode viewed from the acoustic matching member 21 side in the laminated piezoelectric body 30 of the ultrasonic sensor 10 according to the sixth reference example , and FIG. 11 (b) shows the first transmission internal electrode 62, FIG. 11 (c) shows the second transmission / reception internal electrode 63, and FIG. 11 (d) shows the second transmission internal electrode 64. Indicates. It is a side view which shows one side of the transmission / reception apparatus 20 in a 6th reference example .

Embodiments of an ultrasonic sensor that employs a transmission / reception apparatus according to the present invention will be described below with reference to the drawings.
[ First Reference Example ]
In the first reference example , a case where an ultrasonic sensor is mounted on a vehicle and used as an obstacle sensor will be described as an example. As shown in FIG. 1, the ultrasonic sensor 10 mainly includes a box-shaped casing 11 having one end opened, a transmission / reception device 20 that is accommodated in the casing 11 and transmits / receives ultrasonic waves, and the casing 11. And a surface sealing material 12 that protects the transmitting / receiving device 20 and the like housed in the housing 11 by closing the opening. The casing 11 is attached to a predetermined position of the vehicle, for example, a bumper, so as to open outward at the opening.

  The transmission / reception device 20 is connected to the piezoelectric element 22 that transmits / receives ultrasonic waves, and oscillates the ultrasonic waves from the piezoelectric element 22 toward the outside of the ultrasonic sensor 10 and reflects it by an obstacle or the like. And an acoustic matching member 21 that transmits the vibration of the ultrasonic wave to the piezoelectric element 22.

  The piezoelectric element 22 includes a substantially rectangular pillar-shaped laminated piezoelectric body 30 in which a plurality of plate-like electrodes are laminated as internal electrodes so as to be separated from each other by a predetermined distance through the piezoelectric body 33, and the ultrasonic wave when receiving ultrasonic waves. And a pair of external electrodes (hereinafter referred to as the first receiving external electrode 23 and the second receiving external electrode 24) for outputting a voltage in accordance with the laminated piezoelectric body 30 and responding to the ultrasonic waves when transmitting the ultrasonic waves And a pair of external electrodes (hereinafter referred to as a first transmission external electrode 25 and a second transmission external electrode 26) for applying the applied voltage to the laminated piezoelectric body 30. Then, as shown in FIG. 2, the first receiving external electrode 23 and the first transmitting external electrode 25 are provided on one side surface of the laminated piezoelectric body 30, and the second receiving external electrode 24 and the second transmitting external electrode The electrode 26 is provided on the other side facing the one side. The laminated piezoelectric body 30 is joined to one end surface of the acoustic matching member 21 on one end side in the laminating direction (vertical direction in FIG. 1).

  Each internal electrode of the laminated piezoelectric body 30 includes a first internal electrode (hereinafter referred to as a first internal electrode 31) and a second internal electrode (hereinafter referred to as a second internal electrode 32) with a piezoelectric body 33 interposed therebetween. They are stacked alternately in pairs.

  Each first internal electrode 31 is formed in a substantially square shape so that the shape of a cross section (hereinafter referred to as a transverse cross section) perpendicular to the stacking direction is slightly smaller than the piezoelectric body 33 except for the connection portion 31a. Only the portion 31 a is arranged so as to be exposed on one side surface of the laminated piezoelectric body 30. Each second internal electrode 32 is formed in a substantially square shape so that the cross-sectional shape is slightly smaller than the piezoelectric body 33 except for the connection portion 32a, as in the case of the first internal electrode 31. Only the portion 32 a is disposed so as to be exposed on the other side surface of the laminated piezoelectric body 30. In addition, the 1st internal electrode 31 and the 2nd internal electrode 32 are formed with respect to the surface of the lamination direction of the piezoelectric material 33 by printing, such as Ag and PdAg.

  Each piezoelectric body 33 has a rectangular cross section. Each piezoelectric body 33 is made of, for example, lead zirconate titanate (PZT).

  In the multilayer piezoelectric body 30 configured as described above, a part of each first internal electrode 31, specifically, each first internal electrode 31 disposed in the vicinity of the acoustic matching member 21 is connected to the multilayer piezoelectric body 30. On one side surface, the connection part 31 a is connected to the first receiving external electrode 23. Further, each second internal electrode 32 paired with each first internal electrode 31 connected to the first reception external electrode 23 is connected to the second reception electrode by the connection portion 32a on the other side surface of the multilayer piezoelectric body 30. Each is connected to the external electrode 24.

  As a result, the first receiving external electrode 23 and each first internal electrode 31 connected to the first receiving external electrode 23, the second receiving external electrode 24 and the second receiving external electrode 24 are connected. Each of the second internal electrodes 32 and the piezoelectric bodies 33 interposed between the internal electrodes 31 and 32 constitute a receiving unit 27 for outputting an output signal corresponding to the received ultrasonic waves.

  Further, the remaining portion of each first internal electrode 31, specifically, each first internal electrode 31 that is not connected to the first receiving external electrode 23 is connected to a connection portion 31 a on one side surface of the multilayer piezoelectric body 30. Are connected to the first transmission external electrode 25. Each second internal electrode 32 paired with each first internal electrode 31 connected to the first transmission external electrode 25 is connected to the second transmission electrode by the connection portion 32a on the other side surface of the multilayer piezoelectric body 30. Each is connected to the external electrode 26.

  Accordingly, the first transmission external electrode 25 and each first internal electrode 31 connected to the first transmission external electrode 25, the second transmission external electrode 26, and the second transmission external electrode 26 are connected. Each of the second internal electrodes 32 and the piezoelectric bodies 33 interposed between the internal electrodes 31 and 32 constitute a transmitter 28 for transmitting an ultrasonic wave corresponding to the input signal inputted. That is, since the portion of the laminated piezoelectric body 30 that does not constitute the receiving unit 27 is configured as the transmitting unit 28, both the receiving unit 27 and the transmitting unit 28 are configured for one piezoelectric element 22.

  The acoustic matching member 21 is formed to have a square cross section using a resin material having excellent durability such as polycarbonate resin having an acoustic impedance larger than that of air and smaller than that of the piezoelectric element 22. .

  The acoustic matching member 21 is formed so that the thickness in the direction along the stacking direction is about 1/4 of the wavelength in the acoustic matching member 21 of ultrasonic waves. Thus, by forming the thickness of the acoustic matching member 21 to be about ¼ of the wavelength of the ultrasonic wave, a standing wave can be generated in the acoustic matching member 21. As a result, it is possible to reduce the interference between the ultrasonic wave incident into the acoustic matching member 21 and the ultrasonic wave reflected at the interface between the acoustic matching member 21 and the piezoelectric element 22 and cancel each other. Ultrasonic waves can be efficiently transmitted to the element 22. In addition, when used for an ultrasonic sensor having an angle measurement function for detecting an angle by arraying elements, it is desirable that the width of the cross section of the acoustic matching member 21 be equal to or less than half the wavelength of ultrasonic waves in air. .

  In the transmission / reception device 20 configured as described above, the first receiving external electrode 23 and the first transmitting external electrode 25 are electrically connected to the wires 13a and 13c, respectively, as shown in FIGS. Yes. Similarly to the first receiving external electrode 23 and the first transmitting external electrode 25, the second receiving external electrode 24 and the second transmitting external electrode 26 are electrically connected to the wires 13b and 13d, respectively. Yes. Thereby, the transmission / reception apparatus 20 is electrically connected to the circuit element (not shown) which inputs / outputs the input signal and output signal regarding transmission / reception of an ultrasonic wave via each wire 13a-13d. This circuit element is electrically connected to an ECU (Electronic Control Unit: not shown) provided in the vehicle so that a predetermined signal can be input and output.

  The surface sealing material 12 covers the other end surface, which is the end surface facing the one end surface, of the end surface of the acoustic matching member 21, and is fixed to the opening of the housing 11. When this configuration is used, since the interface between the acoustic matching member 21 and the surface sealing material 12 is not exposed to the outside, it is possible to prevent water or the like from entering through the joint surface. Reliability can be improved.

  The surface sealing material 12 is made of a material having an acoustic impedance smaller than that of the acoustic matching member 21 and a high attenuation constant, such as silicon rubber. Further, a material having a low elastic modulus and a material having a low density are preferably used for the surface sealing material 12. For example, a resin containing pores such as a rubber material, an elastomer, and a foamed resin can be used. Since the surface sealing material 12 formed of such a material is interposed between the acoustic matching member 21 and the casing 11, noise can be reduced. Here, the portion of the surface sealing material 12 that covers the other end surface of the acoustic matching member 21 is formed to have a thickness of, for example, 1 mm or less so as not to significantly inhibit transmission of ultrasonic waves.

  In addition, a vibration damping member (not shown) that protects the transmission / reception device 20 from an external force load or impact is provided between the transmission / reception device 20 and the housing 11. The vibration damping member is made of a material having a lower elastic modulus than the piezoelectric element 22, for example, a polymer material such as a soft resin such as urethane, a potting material such as rubber or silicone.

  By providing such a vibration attenuating member, the vibration attenuating member absorbs the shock transmitted to the transmitting / receiving device 20 even when an impact is applied to the acoustic matching member 21 due to a collision of flying objects such as pebbles. At the same time, since the transmission / reception device 20 is prevented from being displaced toward the bottom surface side of the housing 11, the transmission / reception device 20 can be prevented from being destroyed. In addition, since environmental factors such as moisture that degrade the transceiver 20 can be blocked, the reliability can be improved.

Next, detection of an obstacle by the ultrasonic sensor 10 will be described.
First, based on the control signal for controlling the transmission sound pressure and phase of the ultrasonic wave output from the ECU, the circuit element transmits via the first transmission external electrode 25 and the second transmission external electrode 26 of the transmission / reception device 20. An input signal is input to the unit 28. The transmitting unit 28 vibrates based on this input signal, so that ultrasonic waves having a predetermined transmission sound pressure and phase are oscillated.

  Here, since a plurality of pairs of internal electrodes 31 and 32 with the piezoelectric body 33 interposed therebetween are laminated, the transmission unit 28 can obtain a large amplitude corresponding to the number of laminations, and a high transmission sound pressure can be obtained. Sound waves can be oscillated.

  The ultrasonic wave oscillated by the transmission unit 28 of the transmission / reception device 20 is transmitted to the acoustic matching member 21 and transmitted from the other end surface of the acoustic matching member 21 to the outside of the vehicle. When the ultrasonic wave transmitted from the other end surface of the acoustic matching member 21 is reflected by an obstacle, the reflected ultrasonic wave is received by the receiving unit 27 via the other end surface of the acoustic matching member 21 and is output as an output signal. Is converted to

  At this time, since a part of the laminated piezoelectric body 30 is used as the receiving unit 27, the capacitance of the receiving unit 27 can be reduced as compared with the case where the entire part of the laminated piezoelectric body 30 is used as the receiving unit 27. Furthermore, since the laminated piezoelectric body 30 in the vicinity of the acoustic matching member 21 is used as the receiving unit 27, a large distortion occurs at the joint portion between the acoustic matching member 21 and the piezoelectric element 22 according to the ultrasonic wave transmitted from the acoustic matching member 21. Therefore, the output voltage output from the receiving unit 27 is increased, and high reception sensitivity can be maintained.

  The output signal output from the receiving unit 27 is sent to the circuit element via the first receiving external electrode 23 and the second receiving external electrode 24 and is transmitted to the ECU. The circuit element performs arithmetic processing based on the output signal output from the receiving unit 27, measures the position of the obstacle based on the time difference between transmission and reception, and outputs the measurement result to the ECU.

As described above, according to the transmission / reception device 20 of the ultrasonic sensor 10 according to the first reference example , the piezoelectric element 22 is composed of the plurality of first internal electrodes 31 and the plurality of second internal electrodes 32. The laminated piezoelectric bodies 30 are alternately laminated in pairs with each other interposed therebetween. The receiving unit 27 includes a part of each first internal electrode 31 and each second internal electrode 32 in the vicinity of the acoustic matching member 21, each piezoelectric body 33 interposed between the both internal electrodes 31, 32, The transmitter 28 includes a first receiving external electrode 23 and a second receiving external electrode 24, and the transmitter 28 includes the remaining portions of the first internal electrodes 31 and the second internal electrodes 32, and the internal electrodes 31 and 32. Each intervening piezoelectric body 33 is constituted by a first transmission external electrode 25 and a second transmission external electrode 26.

  As described above, since both the receiving unit 27 and the transmitting unit 28 are configured in one piezoelectric element 22, compared with a case where the receiving unit 27 and the transmitting unit 28 are separately configured by a plurality of piezoelectric elements, a transmitting / receiving device is provided. 20 downsizing can be realized.

  In particular, when receiving ultrasonic waves, a part of the laminated piezoelectric body 30 is used as the receiving unit 27, so that the capacitance of the receiving unit 27 is smaller than when using the entire part of the laminated piezoelectric body 30 as the receiving unit. It is possible to suppress and improve reception sensitivity. Furthermore, since a large distortion occurs at the joint portion between the acoustic matching member 21 and the piezoelectric element 22 according to the ultrasonic wave transmitted through the acoustic matching member 21 at the time of reception, the laminated piezoelectric body 30 in the vicinity of the acoustic matching member 21. Is used as the receiving unit 27, the output voltage from the receiving unit 27 is increased, and the receiving sensitivity can be improved.

  Moreover, since the part which does not comprise the receiving part 27 among the laminated piezoelectric bodies 30 is comprised as the transmission part 28, when transmitting the ultrasonic wave by the transmission part 28, a large amplitude corresponding to the number of laminations is obtained, and a higher transmission sound pressure Can oscillate. Therefore, the transmission / reception apparatus 20 according to the present invention in which the reception unit 27 and the transmission unit 28 are integrally provided in one piezoelectric element 22 is compared with the case where the reception unit and the transmission unit are separately configured by a plurality of piezoelectric elements. Miniaturization can be achieved without deteriorating transmission / reception characteristics such as sensitivity and transmission sound pressure.

  In addition, based on the control signal for controlling the ultrasonic transmission sound pressure and phase output from the ECU from the ECU, the input signal to be input to the transmission unit 28 is input to the reception unit 27 at the same time. The receiving unit 27 may be configured to function as a part of the transmitting unit 28. In this case, when transmitting ultrasonic waves, the entire portion of the laminated piezoelectric body 30 can be used as the transmission unit 28, so that a larger amplitude can be obtained and ultrasonic waves with higher transmission sound pressure can be oscillated. .

Next, an ultrasonic sensor 10a according to a second reference example of the present invention will be described with reference to FIG. As shown in FIG. 3, in the second reference example , the point that the transmission / reception device 20 a is employed instead of the transmission / reception device 20 described above is different from the ultrasonic sensor 10 described above, except for the first reference example . It is the same. Hereinafter, other differences from the first reference example will be mainly described. In addition, the same code | symbol is attached | subjected to the component substantially the same as the ultrasonic sensor 10 of a 1st reference example , and the description is abbreviate | omitted.

  The transmission / reception device 20a is configured to employ a piezoelectric element 22a including a laminated piezoelectric body 30a instead of the piezoelectric element 22 with respect to the transmission / reception device 20 described above. The laminated piezoelectric body 30 a is formed so that the cross section of the portion separated from the acoustic matching member 21 is larger than the portion close to the acoustic matching member 21 with respect to the laminated piezoelectric body 30 described above.

Specifically, in the second reference example , the cross section of the laminated piezoelectric body 30a constituting the transmitting unit 28 is larger than the cross section of the laminated piezoelectric body 30a constituting the receiving unit 27 and the cross section of the acoustic matching member 21. It is formed to be large. That is, the cross sections of the internal electrodes 31 and 32 and the piezoelectric body 33 constituting the transmitter 28 are formed larger than the cross sections of the internal electrodes 31 and 32 and the piezoelectric body 33 constituting the receiver 27. Become.

  In the ultrasonic sensor 10a configured as described above, since the cross section of the transmission unit 28 is formed to be large, a larger amplitude is obtained when ultrasonic waves are transmitted by the transmission unit 28, and a higher transmission sound pressure is obtained. Can oscillate.

  Further, since the cross section of the receiving unit 27 is formed to be relatively small with respect to the cross section of the transmitting unit 28, the capacitance of the receiving unit 27 can be increased even when the cross section of the transmitting unit 28 is formed large. Can be kept smaller.

  Note that the cross section of the laminated piezoelectric body 30a constituting the receiving unit 27 may be formed to be smaller than the cross section of the laminated piezoelectric body 30a constituting the transmitting unit 28 and the cross section of the acoustic matching member 21. Good. In this case, in addition to the above-described effects, the cross-sectional area of the joint portion between the acoustic matching member 21 and the laminated piezoelectric body 30a is relatively small, so that distortion generated in the joint portion when receiving ultrasonic waves is further increased. As a result, the output voltage increases and the reception sensitivity can be further increased.

Next, the ultrasonic sensor 10b according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, in the first embodiment, that employs a transceiver 20b in place of the transmitting and receiving device 20 described above is, except that different primary ultrasonic sensor 10 described above, the first reference example It is the same. Hereinafter, other differences from the first reference example will be mainly described. In addition, the same code | symbol is attached | subjected to the component substantially the same as the ultrasonic sensor 10 of a 1st reference example , and the description is abbreviate | omitted.

  The transmission / reception device 20b is configured to employ a piezoelectric element 22b including a laminated piezoelectric body 30b instead of the piezoelectric element 22 with respect to the transmission / reception device 20 described above. The laminated piezoelectric body 30b is formed so that the cross section gradually increases as the laminated piezoelectric body 30 is separated from the acoustic matching member 21 with respect to the laminated piezoelectric body 30 described above.

Specifically, in the first embodiment , the cross section of the laminated piezoelectric body 30 b that constitutes the transmitting unit 28 is greater than the cross section of the laminated piezoelectric body 30 b that constitutes the receiving unit 27 and the cross section of the acoustic matching member 21. Is also formed to be large. Even in this case , similarly to the above-described second reference example , the cross-sections of the internal electrodes 31 and 32 and the piezoelectric body 33 constituting the transmitting unit 28 are represented by the internal electrodes 31 and 32 constituting the receiving unit 27 and The piezoelectric body 33 can be formed larger than the cross section.

  In the ultrasonic sensor 10b configured as described above, since the cross section of the transmission unit 28 is formed to be large, a larger amplitude is obtained when ultrasonic waves are transmitted by the transmission unit 28, and a higher transmission sound pressure is obtained. Can oscillate. In particular, since the cross section of the laminated piezoelectric body 30b is gradually changed, the attenuation of the ultrasonic vibration generated in the transmission unit 28 can be reduced as compared with the case where the cross section of the laminated piezoelectric body 30b is intermittently changed. it can.

  Further, since the cross section of the receiving unit 27 is formed to be relatively small with respect to the cross section of the transmitting unit 28, the capacitance of the receiving unit 27 can be increased even when the cross section of the transmitting unit 28 is formed large. Can be kept smaller.

Note that, similarly to the second reference example , the laminated piezoelectric body 30 a constituting the receiving unit 27 may be formed so that the cross section thereof is smaller than the cross section of the acoustic matching member 21. As a result, in addition to the above-described effects, the cross-sectional area of the joint portion between the acoustic matching member 21 and the laminated piezoelectric body 30b is reduced, so that the distortion generated in the joint portion when receiving ultrasonic waves is further increased. The voltage increases and the receiving sensitivity can be further increased.

[ Third reference example ]
Next, an ultrasonic sensor 10c according to a third reference example of the present invention will be described with reference to FIGS. As shown in FIGS. 5 and 6, the third reference example employs a transmitting / receiving device 20c in place of the above-described transmitting / receiving device 20 in that the ultrasonic sensor 10 described in the first reference example is mainly used. Different. Therefore, substantially the same components as those of the ultrasonic sensor 10 of the first reference example are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIGS. 5 and 6, the transmission / reception device 20 c includes a laminated piezoelectric body 30 c, an acoustic matching member 21, and a second acoustic matching member 21 a instead of the piezoelectric element 22 with respect to the transmission / reception device 20 described above. The piezoelectric element 22c is employed. The multilayer piezoelectric body 30c has substantially the same configuration as the multilayer piezoelectric body 30 described in the first reference example , and the second acoustic matching member 21a is joined to the other end side in the stacking direction of the multilayer piezoelectric body 30c. ing. The second acoustic matching member 21a is the same as the acoustic matching member 21, but a member having substantially the same characteristics may be used.

  The first receiving external electrode 23 is connected to a part of each first internal electrode 31 near the acoustic matching member 21 and each first internal electrode 31 near the second acoustic matching member 21a. It consists of two parts connected to the other part. The second receiving external electrode 24 is a second internal electrode 32 that is paired with each first internal electrode 31 connected to the first receiving external electrode 23, and each second internal electrode 32 in the vicinity of the acoustic matching member 21. It is comprised from two, the site | part connected to the 2nd internal electrode 32, and the site | part connected to each 2nd internal electrode 32 of the 2nd acoustic matching member 21a vicinity.

Thus, in the third reference example , two first receiving external electrodes 23 are provided on one side surface of the laminated piezoelectric body 30c, and two second receiving external electrodes 24 are provided on the other side surface of the laminated piezoelectric body 30c. By being provided, the receiving unit 27 is configured in the vicinity of the acoustic matching member 21 and in the vicinity of the second acoustic matching member 21a. Both the first receiving external electrodes 23 are electrically connected to the common wire 13a, and both the second receiving external electrodes 24 are electrically connected to the common wire 13b.

Similarly to the first reference example , the transmitting unit 28 includes each first internal electrode 31 that is not connected to the first receiving external electrode 23 and each second electrode that is not connected to the second receiving external electrode 24. 2 internal electrodes 32, each piezoelectric body 33 interposed between these internal electrodes 31, 32, and a first transmission external electrode 25 and a second transmission external electrode 26.

As described above, in the transmission / reception device 20c of the ultrasonic sensor 10c according to the third reference example , the second acoustic matching member 21a is joined to the laminated piezoelectric body 30c on the other end side in the lamination direction. The receiving unit 27 is also configured in the vicinity of the second acoustic matching member 21a. As a result, when receiving ultrasonic waves, an output voltage corresponding to a large distortion generated in the joint portion is output from the respective receiving portions 27 in the vicinity of both acoustic matching members 21 and 21a, thereby further improving the reception sensitivity. Can do. Further, both the first receiving external electrodes 23 are electrically connected to the common wire 13a, and both the second receiving external electrodes 24 are electrically connected to the common wire 13b. Since the amount of charge increases, the signal intensity increases, the influence of disturbance noise is suppressed, and the S / N can be improved. The first receiving external electrode 23 and the second second receiving external electrode 24 can be wired separately with each receiving unit 27 without using the common wires 13a and 13b. S / N can also be improved by comparing received ultrasonic signals.

[ Fourth Reference Example ]
Next, an ultrasonic sensor 10 according to a fourth reference example of the present invention will be described with reference to FIGS. As shown in FIGS. 7 and 8, in the fourth reference example , in the ultrasonic sensor 10 described in the first reference example , the internal electrodes 41 to 44 are adopted instead of the internal electrodes 31 and 32, and It is the same as that of the said 1st reference example except that it replaces with each external electrode 23-26 and the point which employ | adopts external electrodes 23a-26a is mainly different. Hereinafter, other differences from the first reference example will be mainly described. In addition, the same code | symbol is attached | subjected to the component substantially the same as the said 1st reference example, and the description is abbreviate | omitted.

In the fourth reference example , as shown in FIGS. 7A to 7D, the first receiving internal electrode 41, the second receiving internal electrode 42, The internal electrode 43 for 1 transmission and the internal electrode 44 for 2nd transmission are employ | adopted. Each dotted line in FIGS. 7A to 7D represents the shape of the cross section of the piezoelectric body 33. The first receiving internal electrode 41 and the second receiving internal electrode 42 are configured as internal electrodes of the receiving unit 27 and are arranged in the vicinity of the acoustic matching member 21. In addition, the first transmission internal electrode 43 and the second transmission internal electrode 44 are configured as internal electrodes of the transmission unit 28 and are disposed in a part away from the acoustic matching member 21.

  Further, each internal electrode 41 to 44 has an external electrode (hereinafter referred to as a first receiving external electrode 23a, a second receiving external electrode 24a, a first transmitting external electrode 25a, and a second transmitting external electrode 26a). Connection portions 41a to 44a connected to are provided. The internal electrodes 41 to 44 are arranged so that the connection portions 41a to 44a are exposed on any one of the four side surfaces of the laminated piezoelectric body 30 having a quadrangular prism shape. As can be seen from FIG. 7, electrodes having the same shape can be used for each of the internal electrodes 41 to 44. Therefore, all of the internal electrodes 41 to 44 are connected to the piezoelectric body by a mask or the like on which one type of electrode pattern is formed. It can form with respect to 33, and can suppress manufacturing cost.

  As shown in FIG. 8, the first receiving external electrode 23 a connected to each first receiving internal electrode 41 is provided on one side surface of the laminated piezoelectric body 30. The second receiving external electrode 24a connected to each second receiving internal electrode 42, the first transmitting external electrode 25a connected to each first transmitting internal electrode 43, and each second transmitting internal Similarly, the second transmission external electrode 26a connected to the electrode 44 is also provided on any one of the remaining side surfaces. Furthermore, each of the external electrodes 23a to 26a is electrically connected to one of the wires 13a to 13d, so that the transmitting / receiving device 20 is electrically connected to the circuit element via the wires 13a to 13d. The

Further, as in the first and third reference examples , each reception external electrode and each transmission external electrode are arranged in a straight line along the stacking direction with respect to one side surface and the other side surface of the multilayer piezoelectric body 30. In the configuration, it is necessary to form each external electrode with high accuracy in order to prevent a short circuit between the receiving unit and the transmitting unit, but in the fourth reference example , by changing the pattern like the internal electrodes 41 to 44, Since only one of the external electrodes 23a to 26a is disposed on one of the side surfaces of the laminated piezoelectric body 30, the external electrodes 23a to 26a need not be formed with high accuracy and can be easily formed. can do.

As described above, according to the transmission / reception device 20 of the ultrasonic sensor 10 according to the fourth reference example , the laminated piezoelectric body 30 is formed in a quadrangular prism shape, and each external electrode connected to each internal electrode 41 to 44, respectively. Since only one of 23a to 26a is arranged for one of the side surfaces of the laminated piezoelectric body 30, two of the external electrodes 23a to 26a are provided on one side surface of the laminated piezoelectric body 30. Since the above is not provided, it is possible to reliably prevent a short circuit between the external electrodes 23a to 26a.

  Further, in order to connect the internal electrodes 41 to 44 to the corresponding external electrodes 23a to 26a, the connection portions 41a to 44a of the internal electrodes 41 to 44 are exposed on the side surfaces of the laminated piezoelectric body 30, respectively. Since the connection part of the internal electrode connected to the other external electrode is not exposed, it is not necessary to position the exposed positions of the connection parts 41a to 44a of the internal electrodes 41 to 44 on the side surface with high accuracy. Further, the manufacturing work of the internal electrodes 41 to 44 is facilitated, and the manufacturing cost of the transmitting / receiving device 20 can be reduced.

Next, an ultrasonic sensor 10 according to a fifth reference example of the present invention will be described with reference to FIGS. 9 and 10. As shown in FIGS. 9 and 10, in the fifth reference example , internal electrodes 51 to 54 are employed instead of the internal electrodes 31 and 32 described above, and external electrodes 23b to 23 are replaced with the external electrodes 23 to 26, respectively. The second reference example is the same as the first reference example except that the point 26b is mainly different. Hereinafter, other differences from the first reference example will be mainly described. In addition, the same code | symbol is attached | subjected to the component substantially the same as the said 1st reference example, and the description is abbreviate | omitted.

In the fifth reference example , as shown in FIGS. 9A to 9D, the first receiving internal electrode 51, the second receiving internal electrode 52, The internal electrode 53 for 1 transmission and the internal electrode 54 for 2nd transmission are employ | adopted. In addition, each dotted line in FIGS. 9A to 9D represents the shape of the cross section of the piezoelectric body 33. The first receiving internal electrode 51 and the second receiving internal electrode 52 are configured as internal electrodes of the receiving unit 27 and are disposed in the vicinity of the acoustic matching member 21. In addition, the first transmission internal electrode 53 and the second transmission internal electrode 54 are configured as internal electrodes of the transmission unit 28 and are disposed in a part away from the acoustic matching member 21.

  Further, each internal electrode 51 to 54 has an external electrode (hereinafter referred to as a first receiving external electrode 23b, a second receiving external electrode 24b, a first transmitting external electrode 25b, and a second transmitting external electrode 26b). Connection portions 51a to 54a connected to the are provided. Further, the internal electrodes 51 to 54 are exposed only on the other side surfaces of the laminated piezoelectric body 30 in which the connection portions 51 a to 54 a are square pillars, and are separated from each other by a predetermined distance along the laminated direction of the laminated piezoelectric body 30. They are arranged in a line.

As shown in FIG. 10, the first receiving external electrode 23 b connected to each first receiving internal electrode 51 and the second receiving external electrode 24 b connected to each second receiving internal electrode 52. The first transmission external electrode 25 b connected to each first transmission internal electrode 53, and the second transmission external electrode 26 b connected to each second transmission internal electrode 54 include the laminated piezoelectric body 30. It is concentrated on the side. Further, each of the external electrodes 23b to 26b is electrically connected to any of the wires 13a to 13d, so that the transmission / reception device 20 is electrically connected to the circuit element via each of the wires 13a to 13d. The In the fifth reference example , as in the third embodiment, the external electrodes 23b to 26b do not need to be formed with high accuracy by changing the pattern as the internal electrodes 51 to 54, and can be easily formed. can do.

As described above, according to the transmission / reception device 20 of the ultrasonic sensor 10 according to the fifth reference example , the internal electrodes 51 to 54 have the connection portions 51 a to 54 a exposed to only the other side surface of the multilayer piezoelectric body 30. Placed in. As a result, the external electrodes 23 b to 26 b connected to the internal electrodes 51 to 54 are concentrated on only the other side surface of the multilayer piezoelectric body 30, so that the transmission / reception device 20 is placed in the casing 11. It is not necessary to make a large insulating space near the side surface where the external electrodes 23b to 26b are not disposed when accommodated in the inside, and the space required for installing the transceiver 20 in the housing 11 can be reduced. The ultrasonic sensor 10 using the transmission / reception device 20 can be reduced in size.

Next, an ultrasonic sensor 10 according to a sixth reference example of the present invention will be described with reference to FIGS. 11 and 12. As shown in FIGS. 11 and 12, in the sixth reference example , internal electrodes 61 to 64 are employed instead of the internal electrodes 31 and 32 described above, and external electrodes 23c to 23 are replaced with the external electrodes 23 to 26, respectively. The second reference example is the same as the first reference example except that the point 26c is mainly different. Hereinafter, other differences from the first reference example will be mainly described. In addition, the same code | symbol is attached | subjected to the component substantially the same as the said 1st reference example, and the description is abbreviate | omitted.

In the sixth reference example , as shown in FIGS. 11A to 11D, the first receiving internal electrode 61, the second receiving internal electrode 62, The internal electrode 63 for 1 transmission and the internal electrode 64 for 2nd transmission are employ | adopted. Each dotted line in FIGS. 11A to 11D represents the shape of the cross section of the piezoelectric body 33. The first receiving internal electrode 61 and the second receiving internal electrode 62 are configured as internal electrodes of the receiving unit 27 and are arranged in the vicinity of the acoustic matching member 21. In addition, the first transmission internal electrode 63 and the second transmission internal electrode 64 are configured as internal electrodes of the transmission unit 28 and are disposed in a part away from the acoustic matching member 21.

  Further, each of the internal electrodes 61 to 64 has an external electrode (hereinafter referred to as a first receiving external electrode 23c, a second receiving external electrode 24c, a first transmitting external electrode 25c, and a second transmitting external electrode 26c). Connection portions 61a to 64a to be connected to are provided. Then, each connection portion 61a of each first receiving internal electrode 61 and each connection portion 63a of each first transmission internal electrode 63 are exposed only on one side surface of the laminated piezoelectric body 30 having a quadrangular prism shape, and the laminated piezoelectric body. 30 are arranged so as to be arranged in a line at a predetermined interval along the stacking direction. Further, each connection portion 62a of each second reception internal electrode 62 and each connection portion 64a of each second transmission internal electrode 64 are exposed only on the other side surface of the multilayer piezoelectric body 30, and the stacking direction of the multilayer piezoelectric body 30 Are arranged so as to be arranged in a line at a predetermined distance from each other.

  Then, as shown in FIG. 12, the first receiving external electrode 23c connected to each first receiving internal electrode 61 and the first transmitting external electrode 25c connected to each first transmitting internal electrode 63. Is provided on one side surface of the laminated piezoelectric body 30. The second receiving external electrode 24c connected to each second receiving internal electrode 62 and the second transmitting external electrode 26c connected to each second transmitting internal electrode 64 are composed of the laminated piezoelectric body 30. On the other side. And each external electrode 23c-26c is each electrically connected to either of wire 13a-13d, and the transmission / reception apparatus 20 is electrically connected to a circuit element via each wire 13a-13d. .

As described above, according to the transmission / reception device 20 of the ultrasonic sensor 10 according to the sixth reference example , the external electrodes 23c to 26c are changed by changing the pattern like the internal electrodes 61 to 64 as in the fourth reference example. Can be easily formed without the need to form the film with high accuracy.

The present invention is not limited to the above embodiments, and may be embodied as follows. Even in this case, the same operations and effects as those of the above embodiments can be obtained.
(1) In the above fourth to sixth reference examples , even when the laminated piezoelectric body 30 is formed in a substantially cylindrical shape, the same effect can be obtained by partially flattening only the external electrode forming surface. When formed in a substantially cylindrical shape, unnecessary vibration can be reduced. Further, by forming only the external electrode forming surface partially flat, electrode formation becomes easy.
(2) In the third reference example , only one of the connection portions 31 a and 32 a of the internal electrodes 31 and 32 is exposed to one of the side surfaces of the laminated piezoelectric body 30, so that the fourth reference is performed. The same effect as the example can be obtained. Further, in the third reference example , by exposing the connection portions 31a and 32a of the internal electrodes 31 and 32 only to predetermined side surfaces of the laminated piezoelectric body 30, the same effect as in the fifth reference example can be obtained. .
(3) In the first reference example , the receiving unit 27 may be configured by using only one first internal electrode 31 and one second internal electrode 32. In this case, although the productivity is slightly inferior to that of a receiving unit configured by using a plurality of internal electrodes 31 and 32, the receiving sensitivity can be further improved by reducing the capacitance of the receiving unit. In the third reference example , the receiving unit 27 is configured by using the first internal electrode 31 and the second internal electrode 32 in the vicinity of the acoustic matching member 21 and in the vicinity of the second acoustic matching member 21a, respectively. A similar effect can be obtained. Further, in the fourth reference example as well, the same effect can be obtained by configuring the receiving unit 27 using only one first receiving internal electrode 41 and one second receiving internal electrode 42.

DESCRIPTION OF SYMBOLS 10-10c ... Ultrasonic sensor 20-20c ... Transmitter / receiver 21 ... Acoustic matching member 21a ... Second acoustic matching member 22-22c ... Piezoelectric element 23-23c ... First receiving external electrode (first receiving external electrode) )
24 to 24c: second receiving external electrode (second receiving external electrode)
25 to 25c: first transmission external electrode (first transmission external electrode)
26 to 26c ... second transmission external electrode (second transmission external electrode)
27: Receiver 28 ... Transmitter 31 ... First internal electrode (first internal electrode)
32 ... 2nd internal electrode (2nd internal electrode)
33 ... Piezoelectric bodies 41, 51, 61 ... First reception internal electrodes 42, 52, 62 ... Second reception internal electrodes 43, 53, 63 ... First transmission internal electrodes 44, 54, 64... Second transmitting internal electrode

Claims (5)

A transmission / reception device including a piezoelectric element that transmits and receives ultrasonic waves via an acoustic matching member,
The piezoelectric element is
A plurality of first internal electrodes and a plurality of second internal electrodes are alternately stacked in pairs with a piezoelectric body interposed therebetween, and are bonded to the acoustic matching member at one end in the stacking direction. Body,
A first receiving external electrode connected to a part of each of the first internal electrodes in the vicinity of the acoustic matching member;
A second receiving external electrode connected to each second internal electrode paired with a portion of each first internal electrode;
A first transmission external electrode connected to the remainder of each first internal electrode;
A second transmitting external electrode connected to each second internal electrode paired with the remainder of each first internal electrode,
The first receiving external electrode and the one or more first internal electrodes connected to the first receiving external electrode, the second receiving external electrode, and the second receiving external electrode A receiving unit for outputting an output signal corresponding to the ultrasonic wave received by one or more of the second internal electrodes connected to the electrodes and the piezoelectric bodies interposed between the two internal electrodes; Configured,
The first transmission external electrodes and the first internal electrodes connected to the first transmission external electrodes, the second transmission external electrodes and the second transmission external electrodes. A transmission unit configured to transmit the ultrasonic wave corresponding to an input signal input by each of the second internal electrodes and each of the piezoelectric bodies interposed between the two internal electrodes,
The transmission / reception apparatus according to claim 1, wherein a cross section of the laminated piezoelectric body perpendicular to the laminating direction is formed so as to be gradually separated from the acoustic matching member . The laminated piezoelectric body has a second acoustic matching member bonded to the other end side in the laminating direction,
The first receiving external electrode includes a part of one or more of the first internal electrodes in the vicinity of the acoustic matching member and one or more of the first inner parts in the vicinity of the second acoustic matching member. Connected to the other part of the electrode,
2. The second receiving external electrode is connected to a second internal electrode paired with the first internal electrode connected to the first receiving external electrode. The transmitter / receiver described. The laminated piezoelectric body is formed in a polygonal column shape having a plurality of side surfaces along the lamination direction,
The said each external electrode is each provided on each said side surface so that only one may be arrange | positioned with respect to one of each said side surface, The Claim 1 or Claim 2 characterized by the above-mentioned. Transmitter / receiver. The said each external electrode is provided in a part of cross-sectional outer edge orthogonal to the said lamination direction on the side surface along the said lamination direction of the said laminated piezoelectric material. Transmitter / receiver.   An ultrasonic sensor comprising the transmission / reception device according to claim 1, wherein the ultrasonic transmission / reception is performed by the transmission / reception device.

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