JP2018157457A - Ultrasonic sensor and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic sensor having high azimuth resolution and an electronic device.SOLUTION: The ultrasonic sensor includes: a substrate having a surface on which a plurality of recesses are provided and a surface on which a plurality of ultrasonic elements are provided; and an acoustic layer filled in the recesses. When viewed from a thickness direction of the substrate, the ultrasonic elements are provided at a position overlapping the recesses. The interface facing a bottom surface of the recesses of the acoustic layer has an inclination with respect to the bottom surface of the recesses.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ultrasonic sensor and an electronic device.

2. Description of the Related Art Conventionally, an ultrasonic sensor that transmits / receives ultrasonic waves to / from a measurement target is known (see, for example, Patent Document 1).
The ultrasonic sensor described in Patent Document 1 is an ultrasonic sensor provided in a bumper of a vehicle, and is a sensor having a long distance range 2 m or more away from the vehicle as a detection area. The ultrasonic sensor includes a piezoelectric element and an acoustic matching layer bonded to one surface of the piezoelectric element, and a surface opposite to the one surface of the acoustic matching layer is inclined at an angle α with respect to the one surface. Have

JP 2011-39003 A

By the way, the technique described in Patent Document 1 is an ultrasonic sensor for detecting an obstacle as far as possible from the vehicle. For the extension of such a technique, unmanned operation of the vehicle is desired. It is rare. In such an unmanned driving technique for a vehicle, detection of an obstacle within a close range and a wide angle range, which has been conventionally determined by human observation, is necessary for avoiding danger.
In the technique of Patent Document 1, the surface of the acoustic matching layer opposite to the piezoelectric element is inclined by an angle α in accordance with the inclination angle α of the bumper. In this case, an obstacle at a long distance can be detected. However, it is not possible to suitably detect an obstacle for a wide angle range within a close range.
In other words, when transmitting ultrasonic waves from the ultrasonic sensor, the ultrasonic beam is output in a direction different from the main lobe in addition to the main lobe formed in the direction corresponding to the inclination angle α of the acoustic matching layer. Occurs. Here, in the ultrasonic sensor described in Patent Document 1, this side lobe is not considered, and when a reflected wave by the side lobe is received, it is determined that an obstacle exists in the transmission direction of the ultrasonic wave of the main lobe. It will be. In other words, Patent Document 1 has a problem that the azimuth resolution is insufficient and an obstacle in a wide angle range within a short distance cannot be detected.

  An object of the present invention is to provide an ultrasonic sensor and an electronic device with high azimuth resolution.

  An ultrasonic sensor according to an application example of the present invention includes a substrate in which a surface provided with a plurality of recesses and a surface provided with a plurality of ultrasonic elements are opposite to each other, and an acoustic layer filled in the recesses When viewed from the thickness direction of the substrate, the ultrasonic element is provided at a position overlapping the recess, and the interface of the acoustic layer facing the bottom surface of the recess is inclined with respect to the bottom surface of the recess. It is characterized by having.

In this application example, a plurality of concave portions and a plurality of ultrasonic elements provided at positions overlapping with the concave portions are provided on the substrate, and each concave portion is filled with an acoustic layer. And in this application example, the interface which opposes the bottom face of the recessed part of this acoustic layer has inclination with respect to the bottom face of the recessed part in which an ultrasonic element is provided. That is, the normal direction of the interface facing the bottom surface of the recess of the acoustic layer is different from the normal direction of the bottom surface of the recess. In such a configuration, ultrasonic waves can be transmitted and received in a plurality of directions by setting the interfaces of the acoustic layers provided in the plurality of recesses in different directions.
As an example, a first ultrasonic transducer (configured by one recess, an ultrasonic element, and an acoustic layer) whose angle with respect to the bottom surface of the interface is a first angle, and a second angle whose interface is different from the first angle, An ultrasonic sensor including the second ultrasonic transducer will be described. In this case, although the main lobe is formed in the first direction in the direction corresponding to the first angle by the first ultrasonic transducer, the side lobe is generated in a direction different from the main lobe. On the other hand, the ultrasonic transmission / reception direction of the second ultrasonic transducer is the second direction corresponding to the second angle. Here, when the direction of the side lobe generated by the first ultrasonic transducer is the second direction, the ultrasonic wave reflected by the side lobe is output by the second ultrasonic transducer. It can be detected as a reflected wave from the direction. Thereby, the azimuth | direction resolution in an ultrasonic sensor can be improved.

In the ultrasonic sensor according to this application example, the plurality of recesses include a first recess and a second recess, and the velocity of sound propagating through the acoustic layer filled in the first recess is filled in the second recess. It is preferable that the velocity of sound propagates through the acoustic layer.
In this application example, the propagation speed of ultrasonic waves differs between the acoustic layer of the first recess and the acoustic layer of the second recess. In this case, the direction of refraction of the ultrasonic wave at the interface of the acoustic layer of the first recess and the direction of refraction of the ultrasonic wave at the interface of the acoustic layer of the second recess are different from each other, and the direction of transmission / reception of the ultrasonic wave is also different. It becomes. Thereby, transmission / reception of ultrasonic waves in a plurality of directions becomes possible, and a decrease in azimuth resolution can be suppressed.

In the ultrasonic sensor according to this application example, the acoustic layer includes an acoustic layer filled in the recess and an acoustic layer stacked on the opposite side of the bottom surface of the recess, and on the opposite side of the bottom surface of the recess. The speed of sound propagating through the laminated acoustic layer is preferably different from the speed of sound propagating through the acoustic layer filled in the recess.
In this application example, the propagation speed of ultrasonic waves differs between the acoustic layer located on the bottom surface side of the recess and the acoustic layer opposite to the bottom surface of the recess laminated on the acoustic layer. For this reason, ultrasonic waves are refracted at the boundary (interface) between the acoustic layer on the bottom surface side of the recess and the acoustic layer laminated on the opposite side of the bottom surface, and the transmission / reception direction of the ultrasonic waves can be changed. .

In the ultrasonic sensor of this application example, it is preferable that the acoustic layer filled in the first recess and the acoustic layer filled in the second recess are made of different materials.
In this application example, the materials of the acoustic layer filled in the first recess and the acoustic layer filled in the second recess are different. Thereby, it is possible to change the transmission / reception direction of the ultrasonic wave transmitted / received from the acoustic layer filled in the first concave portion and the ultrasonic wave transmitted / received from the acoustic layer filled in the second concave portion with a simple configuration. It becomes.

In the ultrasonic sensor according to this application example, it is preferable that the acoustic layer filled in the recess and the acoustic layer stacked on the opposite side of the bottom surface of the recess are made of different materials.
In this application example, the materials of the acoustic layer positioned on the bottom surface side of the recess and the acoustic layer stacked on the opposite side of the bottom surface of the recess are different. Thereby, the transmission / reception direction of an ultrasonic wave can be changed with a simple configuration.

An electronic apparatus according to an application example of the invention includes an ultrasonic sensor as described above and a control unit that controls the ultrasonic sensor.
The electronic apparatus of this application example includes the ultrasonic sensor as described above. Therefore, it is possible to transmit and receive ultrasonic waves with high azimuth resolution by the ultrasonic sensor, and it is possible to perform highly accurate control in the electronic device. For example, when an object is detected by an ultrasonic sensor and a predetermined operation process is performed on the object, the object can be appropriately detected, and the operation process on the object is preferably performed. it can.

The figure which shows schematic structure of the ultrasonic sensor of 1st embodiment. The top view which shows schematic structure of the ultrasonic transmission / reception part of 1st embodiment. Sectional drawing which shows schematic structure of the ultrasonic transmission / reception part cut | disconnected by the AA line of FIG. The figure which shows the transmission direction of the ultrasonic wave in the ultrasonic transmission / reception part of 1st embodiment. The figure which shows the propagation path of an ultrasonic wave at the time of receiving the ultrasonic wave from the normal line direction of a bottom face in the ultrasonic transmission / reception part of 1st embodiment. The figure which shows the propagation path of an ultrasonic wave in the case of receiving an ultrasonic wave from the 2nd direction which inclines with respect to the normal line direction of a bottom face in the ultrasonic transmission / reception part of 1st embodiment. The block diagram which shows schematic structure of the circuit board of the ultrasonic sensor of 1st embodiment. The figure which shows the manufacturing method of the ultrasonic transmission / reception part of 1st embodiment. The figure which shows the manufacturing method of the ultrasonic transmission / reception part of 2nd embodiment. Sectional drawing which shows schematic structure of the ultrasonic transmission / reception part of 3rd embodiment. The figure which shows the transmission direction of the ultrasonic wave in the ultrasonic transmission / reception part of 3rd embodiment. The figure which shows the propagation path of an ultrasonic wave in the case of receiving an ultrasonic wave from the 4th direction which inclines with respect to the normal line direction of a bottom face in the ultrasonic transmission / reception part of 3rd embodiment. The perspective view which shows schematic structure of the moving body as an electronic device to which an ultrasonic sensor is applied. The perspective view which shows schematic structure of the robot as an electronic device to which an ultrasonic sensor is applied. The perspective view which shows schematic structure of the ultrasonic diagnosing device as an electronic device to which an ultrasonic sensor is applied.

[First embodiment]
Hereinafter, the ultrasonic sensor 10 according to the first embodiment will be described.
[1. Schematic configuration of ultrasonic sensor 10]
FIG. 1 is a diagram showing a schematic configuration of an ultrasonic sensor 10 of the present embodiment.
As shown in FIG. 1, the ultrasonic sensor 10 includes an ultrasonic transmission / reception unit 20, a sealing plate 12, a circuit board 13, and a protective case 11.

The ultrasonic transmission / reception unit 20 is a part that transmits and receives ultrasonic waves.
The sealing plate 12 is joined to the ultrasonic transmission / reception unit 20 and reinforces the ultrasonic transmission / reception unit 20. Specifically, the sealing plate 12 is bonded to a second surface 21B of the substrate 21 of the ultrasonic transmission / reception unit 20 described later by a bonding member such as an epoxy resin, for example.
The circuit board 13 is electrically connected to the ultrasonic transmission / reception unit 20 and is provided with various circuits for controlling the ultrasonic transmission / reception unit 20.
The protective case 11 is a case that protects the ultrasonic transmitting / receiving unit 20, the sealing plate 12, and the circuit board 13. A part of the protective case 11 is provided with a connector 11A, and the circuit board 13 is connected to the connector 11A.

And this ultrasonic sensor 10 detects a target object by transmitting an ultrasonic wave from the ultrasonic transmission / reception part 20 and receiving the ultrasonic wave reflected by the target object.
Hereinafter, each configuration will be described in detail.

[2. Configuration of Ultrasonic Transceiver 20]
FIG. 2 is a plan view of the ultrasonic transmission / reception unit 20, and FIG. 3 is a cross-sectional view of the ultrasonic transmission / reception unit 20 cut along the line AA in FIG.
As shown in FIG. 2, a plurality of ultrasonic transducers Tr are arranged in a two-dimensional array along the X direction (scan direction) and the Y direction (slice direction) intersecting each other in the ultrasonic transmission / reception unit 20. ing. In the present embodiment, a plurality of ultrasonic transducers Tr (ultrasonic elements) arranged in the Y direction form a 1CH (channel) transmission / reception string Ch (vibrator). Further, the ultrasonic transmission / reception unit 20 having a one-dimensional array structure is configured by arranging a plurality of the 1CH transmission / reception columns Ch along the Y direction. Here, in the ultrasonic transmission / reception unit 20, an area where the ultrasonic transducer Tr is arranged is referred to as an array area Ar1.
In FIG. 2, for convenience of explanation, the number of ultrasonic transducers Tr is reduced, but in reality, more ultrasonic transducers Tr are arranged. In this embodiment, an example in which the X direction and the Y direction are orthogonal to each other is shown, but the present invention is not limited to this, and the Y direction and the X direction may be inclined at an angle different from 90 °.
And the ultrasonic transmission / reception part 20 is comprised including the board | substrate 21, the piezoelectric element 22, and the acoustic layer 23, as shown in FIG.

[2-1. Configuration of Substrate 21]
The substrate 21 has a first surface 21A on the side where ultrasonic waves are transmitted and received and a second surface 21B on which the piezoelectric element 22 is provided, and the first surface 21A is provided with a plurality of recesses 21C. Yes. More specifically, the substrate 21 includes a base 211 having a through hole 211A, and a support film 212 that is provided on the second surface 21B side of the base 211 and closes one end of the through hole 211A. Each recess 21 </ b> C is configured by an inner peripheral surface of the through hole 211 </ b> A and a surface of the vibrating portion 212 </ b> A (the bottom surface 212 </ b> A <b> 1 of the recess 21 </ b> C) that closes the through hole 211 </ b> A of the support film 212.
These concave portions 21C are provided corresponding to the positions where the ultrasonic transducer Tr is provided. That is, the recesses 21 </ b> C are arranged in a lattice shape with respect to the X direction and the Y direction in a plan view of the substrate 21 viewed from the substrate thickness direction.

[2-2. Configuration of Piezoelectric Element 22]
The piezoelectric element 22 corresponds to an ultrasonic element, and is provided on the second surface 21 </ b> B of the substrate 21 at a position overlapping with each recess 21 </ b> C. As shown in FIG. 3, the piezoelectric element 22 is constituted by a laminated body in which a lower electrode 221, a piezoelectric film 222, and an upper electrode 223 are laminated from the support film 212 side.
In such a piezoelectric element 22, when a rectangular wave voltage (drive signal) having a predetermined frequency is applied between the lower electrode 221 and the upper electrode 223, the piezoelectric film 222 is bent to vibrate the vibration part 212A and the concave part 21C side. Is sent out. Further, when an ultrasonic wave is incident from the concave portion 21 </ b> C and the vibrating portion 212 </ b> A is vibrated, a potential difference is generated between the upper and lower sides of the piezoelectric film 222. Accordingly, the received ultrasonic wave can be detected by detecting a potential difference generated between the lower electrode 221 and the upper electrode 223.

  Further, in this embodiment, as shown in FIG. 2, the lower electrode 221 is formed in a straight line along the Y direction, and connects a plurality of ultrasonic transducers Tr constituting the 1CH transmission / reception string Ch. . The drive terminal 221A is electrically connected to the circuit board 13 through a through electrode provided on the sealing plate 12, for example.

  The upper electrode 223 is formed in a straight line along the X direction, and connects the ultrasonic transducers Tr arranged in the X direction. The ± X side end of the upper electrode 223 is connected to the common electrode line 224. The common electrode line 224 connects a plurality of upper electrodes 223 arranged along the Y direction, and a common terminal 224A electrically connected to the circuit board 13 is provided at an end thereof. The common terminal 224A is electrically connected to the circuit board 13 through a through electrode provided on the sealing plate 12, for example.

[2-3. Configuration of acoustic layer 23]
The acoustic layer 23 includes an inner acoustic layer 231 provided on the vibration portion 212A (bottom surface 212A1) side of the concave portion 21C and an outer acoustic layer laminated on the inner acoustic layer 231 on the side opposite to the vibration portion 212A (bottom surface 212A1) of the concave portion 21C. A layer 232. In the present embodiment, the ultrasonic transducer Tr is configured by the vibration unit 212A, the piezoelectric element 22, and the acoustic layer 23 (the inner acoustic layer 231 and the outer acoustic layer 232).

The inner acoustic layer 231 is filled in the recess 21C, and the end surface opposite to the vibrating portion 212A (interface 233 with the outer acoustic layer 232) is inclined at different angles depending on the transmission / reception direction of the ultrasonic waves.
Specifically, in the present embodiment, the plurality of ultrasonic transducers Tr arranged in the array region Ar1 includes a first transducer Tr1 that transmits and receives ultrasonic waves in the normal direction of the bottom surface 212A1, and a bottom surface 212A1. A second transducer Tr2 and a third transducer Tr3 that transmit and receive ultrasonic waves in a direction inclined at a predetermined angle with respect to the normal direction.
In addition, in one transmission / reception row Ch, an ultrasonic transducer Tr having the same ultrasonic transmission / reception direction is arranged. Therefore, in the array area Ar1, the transmission / reception column Ch in which the first transducer Tr1 is arranged in the Y direction, the transmission / reception column Ch in which the second transducer Tr2 is arranged in the Y direction, and the third transducer Tr3 are arranged in the Y direction. A plurality of transmission / reception columns Ch are provided.

Next, the angle of the interface 233 between the inner acoustic layer 231 and the outer acoustic layer 232 of each of the transducers Tr1, Tr2, Tr3 will be described.
In the first transducer Tr1, the interface 233 of the inner acoustic layer 231 coincides (or substantially coincides) with the normal direction of the bottom surface 212A1.
On the other hand, in the second transducer Tr2, the interface 233 is inclined at an angle α (0 <α <90) with respect to the normal direction of the bottom surface 212A1. That is, the interface 233 has an inclination with respect to the bottom surface 212A1.
In the third transducer Tr3, the interface 233 of the inner acoustic layer 231 is inclined at an angle −α with respect to the normal direction of the bottom surface 212A1. That is, the interface 233 has an inclination with respect to the interface 212A1.
In the present embodiment, it is assumed that the reference plane S ₀ is parallel to the plane (XY plane) on which the bottom surface 212A1 is disposed, with the intersection point between the interface 233 and the side surface (wall portion 211B) on the −X side of the recess 21C as the origin. In this case, the plane tan α in the XZ plane and the plane parallel to the Y axis becomes the interface 233 of the inner acoustic layer 231 in the second transducer Tr2. In addition, the plane tan (−α) in the XZ plane and the plane parallel to the Y axis is the interface 233 of the inner acoustic layer 231 in the third transducer Tr3.

FIG. 4 is a diagram illustrating the transmission direction of ultrasonic waves in the present embodiment.
In the present embodiment, the inner acoustic layer 231 and the outer acoustic layer 232 are made of different materials, and the velocity of the ultrasonic wave propagating through the inner acoustic layer 231 (the speed of sound in the inner acoustic layer 231) is outside. It is greater than the speed of sound in the acoustic layer 232.
Therefore, as shown in FIG. 4, the ultrasonic transmission direction in the second transducer Tr2 is inclined to the + X side with respect to the ultrasonic transmission direction (first direction D1) in the first transducer Tr1. . Further, the transmission direction of the ultrasonic waves in the third transducer Tr3 is inclined to the −X side with respect to the first direction D1.
Furthermore, when the speed of sound in the target to which ultrasonic waves are propagated from the ultrasonic transmission / reception unit 20 is larger than that of the outer acoustic layer 232, the transmission direction of the ultrasonic waves in the second transducer Tr2 is further inclined toward the + X side (second). Direction D2). Similarly, the transmission direction of the ultrasonic wave in the third transducer Tr3 is further inclined to the −X side (third direction D3).

FIG. 5 is a diagram illustrating an ultrasonic wave propagation path when the ultrasonic wave is received from the normal direction of the bottom surface 212A1.
When the ultrasonic wave is input from the normal direction of the bottom surface 212A1, the ultrasonic wave is input from the normal direction of the bottom surface 212A1 to the vibration part 212A of the first transducer Tr1. On the other hand, in the second transducer Tr2 and the third transducer Tr3, the ultrasonic waves are refracted by the interface 233 and the ultrasonic waves reaching the bottom surface 212A1 are reduced, so that the vibration of the vibrating portion 212A is also reduced. Therefore, the signal value output from the second transducer Tr2 or the third transducer Tr3 is smaller than the signal value output from the first transducer Tr1.

FIG. 6 is a diagram illustrating an ultrasonic propagation path when ultrasonic waves are received from the second direction D2.
When the ultrasonic wave is input from the second direction D2, the ultrasonic wave is input from the normal direction of the bottom surface 212A1 to the vibrating portion 212A of the second transducer Tr2. On the other hand, in the first transducer Tr1 and the third transducer Tr3, the ultrasonic wave is refracted by the interface 233 and the ultrasonic wave reaching the vibration part 212A is reduced, so the vibration of the vibration part 212A is also reduced. Therefore, the signal value output from the first transducer Tr1 or the third transducer Tr3 is smaller than the signal value output from the second transducer Tr2.
Although illustration is omitted, the same applies to the case where an ultrasonic wave is input from the third direction D3. In this case, the signal value from the third transducer Tr3 is transmitted from the first transducer Tr1 or the second transducer Tr2. Also grows.

  As described above, in the ultrasonic sensor 10 of the present embodiment, the traveling direction of the ultrasonic waves transmitted from the first transducer Tr1, the second transducer Tr2, and the third transducer Tr3 changes, and the It is possible to selectively receive an ultrasonic wave returned (input) from a direction.

[3. Configuration of Sealing Plate 12]
Next, the sealing plate 12 constituting the ultrasonic sensor 10 will be described. The sealing plate 12 is bonded to the substrate 21 and reinforces the substrate 21. The sealing plate 12 is formed so as to cover, for example, a region of the substrate 21 where the ultrasonic transducer Tr is disposed in a plan view as viewed from the Z direction. For example, a semiconductor substrate such as Si or an insulating substrate is used. Consists of. In addition, since the material and thickness of the sealing plate 12 affect the frequency characteristics of the ultrasonic transducer Tr, it is preferable to set based on the center frequency of the ultrasonic wave transmitted and received by the ultrasonic transducer Tr.

For example, the sealing plate 12 is bonded to the substrate 21 by a bonding member (not shown) formed on the support film 212 of the substrate 21. This joining member is provided in a region other than the concave portion 21C of the substrate 21 (for example, a wall portion 211B between the concave portions 21C). Therefore, the vibration of the support film 212 is not inhibited by the bonding member, and crosstalk between the ultrasonic transducers Tr can be suppressed.
Although not shown, the sealing plate 12 includes a hole facing the drive terminal 221A and the common terminal 224A, and a wiring portion that connects the drive terminal 221A and the common terminal 224A and the circuit board 13 to the hole. Is provided. The wiring part may be, for example, a through electrode, a lead wire, an FPC, or the like.

[4. Configuration of Circuit Board 13]
FIG. 7 is a block diagram showing a schematic configuration of the circuit board 13 in the first embodiment.
The circuit board 13 includes a connection terminal 134 connected to the drive terminal 221 </ b> A and the common terminal 224 </ b> A of the ultrasonic transmission / reception unit 20. Further, as shown in FIG. 7, the circuit board 13 includes, for example, a selection circuit 131, a transmission circuit 132, and a reception circuit 133 as various circuits that control transmission / reception of ultrasonic waves by the ultrasonic transmission / reception unit 20. Further, the circuit board 13 includes an external connection terminal 135 connected to the connector 11A.
The common terminal 224A is connected to a ground circuit or the like on the circuit board 13 and is maintained at a predetermined common potential.

  The selection circuit 131 is connected to the connection terminal 134 connected to the drive terminal 221 </ b> A, the transmission circuit 132, and the reception circuit 133, and switches between transmission processing and reception processing in the ultrasonic transmission / reception unit 20. That is, in the ultrasonic transmission / reception unit 20, when transmitting an ultrasonic wave, the transmission terminal is switched to a transmission mode in which the connection terminal 134 and the transmission circuit 132 are connected. Switch to the reception mode to connect the. By alternately switching between the transmission mode and the reception mode by the selection circuit 131, it is possible to transmit an ultrasonic wave from the ultrasonic transmission / reception unit 20 and receive an ultrasonic wave (reflected wave) reflected by an object.

In the transmission mode, the transmission circuit 132 outputs a drive signal to be input to each ultrasonic transducer Tr (transmission / reception column Ch).
In the reception mode, the reception circuit 133 receives the detection signal output from each ultrasonic transducer Tr (transmission / reception sequence Ch). For example, the reception circuit 133 is configured to include a low noise amplification circuit, a voltage control attenuator, a programmable gain amplifier, a low pass filter, an A / D converter, etc., and converts a detection signal into a digital signal, removal of a noise component, Each signal processing such as amplification to a desired signal level is performed.
The selection circuit 131, the transmission circuit 132, and the reception circuit 133 are connected to the connector 11A via the external connection terminal 135. The ultrasonic sensor 10 is connected to the electronic device via the connector 11A, so that it can perform transmission / reception processing of ultrasonic waves based on a command from the electronic device and output a reception signal to the electronic device. Become.

  In the present embodiment, as described above, the ultrasonic transducer Tr includes the first transducer Tr1, the second transducer Tr2, and the third transducer Tr3. Therefore, in the transmission mode, by inputting a drive signal to each ultrasonic transducer Tr, ultrasonic waves are transmitted in each of the first direction D1, the second direction D2, and the third direction D3. It becomes possible to transmit. On the other hand, in the reception mode, ultrasonic waves from the first direction D1, the second direction D2, and the third direction D3 are received by the ultrasonic transducer Tr corresponding to each direction. Therefore, it is possible to determine from which direction the ultrasonic wave is received based on the ultrasonic transducer Tr that is the output source of the detection signal.

[5. Method for manufacturing ultrasonic transmission / reception unit 20]
Next, a method for manufacturing the ultrasonic transmission / reception unit 20 in the ultrasonic sensor 10 as described above will be described. In addition, about the manufacture of the board | substrate 21 with which the piezoelectric element 22 was laminated | stacked, it can manufacture by the conventional method (for example, refer Unexamined-Japanese-Patent No. 2013-175879). Therefore, here, a method for manufacturing the acoustic layer 23 will be described.
FIG. 8 is a diagram illustrating an example of a method for manufacturing the ultrasonic transmission / reception unit 20.
When manufacturing the ultrasonic transmission / reception unit 20, first, as illustrated in the first part of FIG. 8, the substrate 21 on which the piezoelectric elements 22 are stacked is manufactured.

  Next, as shown second in FIG. 8, the inner acoustic layer 231 is filled into the recess 21 </ b> C of the substrate 21. At this time, the inner acoustic layer 231 is filled by vacuum replacement or the like so that bubbles do not remain in the recess 21C.

Then, after the inner acoustic layer 231 is solidified, a grinding process is performed as shown in the third part of FIG. For example, the inner acoustic layer 231 is ground along the Y direction using a dicer 90 provided with a first inclined surface 91 having an angle α and a second inclined surface 92 having an angle −α on the cutter surface. Thereby, the interface 233 of the inner acoustic layer 231 of the second transducer Tr2 is inclined at an angle α, and the interface 233 of the inner acoustic layer 231 of the third transducer Tr3 is inclined at an angle −α. Further, the inner acoustic layer 231 of the first transducer Tr1 may not be ground, and may be ground in parallel with the bottom surface 212A1.
Further, after the grinding process, the inner acoustic layer 231 may be coated to smooth the surface.

Thereafter, the outer acoustic layer 232 is applied on the inner acoustic layer 231.
Thus, as shown in the fourth part of FIG. 8, the ultrasonic transmission / reception unit 20 including the first transducer Tr1, the second transducer Tr2, and the third transducer Tr3 is manufactured.

[5. Effects of this embodiment]
In the present embodiment, the ultrasonic sensor 10 includes a substrate 21 having a plurality of recesses 21C on the first surface 21A, and a piezoelectric element 22 provided on the second surface 21B side of the vibration part 212A constituting the bottom surface 212A1 of the recess 21C. And the acoustic layer 23 filled in the recess 21C. In the present embodiment, one ultrasonic transducer Tr is configured by one concave portion 21C, the piezoelectric element 22, and the acoustic layer 23 (the inner acoustic layer 231 and the outer acoustic layer 232). Among the plurality of ultrasonic transducers Tr, in the second transducer Tr2 and the third transducer Tr3, the normal line of the interface 233 opposite to the vibrating portion 212A of the inner acoustic layer 231 is the normal line of the bottom surface 212A1. It is inclined with respect to.
For this reason, in the transmission mode, by transmitting ultrasonic waves from the second transducer Tr2 and the third transducer Tr3 in addition to the first transducer Tr1, the ultrasonic waves are transmitted to a wide angle range including proximity. can do.
Further, for example, even when a side lobe occurs in the second direction D2 or the third direction D3 in the first transducer Tr1, a reflected wave due to the side lobe is received by the second transducer Tr2 or the third transducer Tr3. To do. That is, it can be easily detected from which direction each reflected wave is input, and the azimuth resolution can be improved.

In the present embodiment, the acoustic layer 23 includes the inner acoustic layer 231 filled in the concave portion 21C on the vibration portion 212A side of the concave portion 21C and the outer acoustic layer laminated on the inner acoustic layer 231 on the opposite side to the vibration portion 212A. Layer 232. The inner acoustic layer 231 and the outer acoustic layer 232 are made of different materials, and the speeds of ultrasonic waves propagating in the acoustic layer 23 are different. That is, the sound speed in the inner acoustic layer 231 is greater than the sound speed in the outer acoustic layer 232.
In such a configuration, when the ultrasonic wave propagates from the inner acoustic layer 231 to the outer acoustic layer 232 in the second transducer Tr2 and the third transducer Tr3, the ultrasonic wave is refracted at a desired angle at the interface 233. The transmission / reception direction of ultrasonic waves can be expanded to a desired range.
In addition, as described above, the transmission / reception direction of ultrasonic waves can be expanded to a wide angle range by a simple configuration in which the forming materials of the inner acoustic layer 231 and the outer acoustic layer 232 are different materials.

  Furthermore, in this embodiment, the speed of sound in the outer acoustic layer 232 is smaller than the speed of sound in a target for transmitting ultrasonic waves by the ultrasonic sensor 10. Thereby, as shown in FIG. 4, the transmission / reception direction of an ultrasonic wave can be expanded more.

  Further, when a bulk type piezoelectric body is vibrated, the frequency is determined by the thickness dimension of the piezoelectric body. On the other hand, in this case, if the adjacent piezoelectric bodies have an array configuration with a fine pitch of 30 μm or less, for example, when a voltage is applied to each piezoelectric body, the piezoelectric body swings in a direction crossing the thickness direction, and an appropriate frequency is obtained. Cannot output ultrasonic waves. On the other hand, in the present embodiment, a thin film type ultrasonic transducer Tr provided with the piezoelectric element 22 is used for the vibrating portion 212A of the concave portion 21C of the substrate 21. In this case, a fine pitch width such as 30 μm can be set between the ultrasonic transducers Tr. Therefore, it is possible to suitably scan the transmission / reception direction of the ultrasonic waves by delay driving each ultrasonic transducer Tr.

[Second Embodiment]
Next, a second embodiment will be described.
In the first embodiment, the example in which the acoustic layer 23 of the ultrasonic transmitting / receiving unit 20 is manufactured by the grinding process using the dicer 90 has been described. In contrast, the second embodiment is different from the first embodiment in the method of manufacturing the ultrasonic transmission / reception unit 20.
In the following description, the same reference numerals are given to the configurations already described, and the description thereof is omitted or simplified.

FIG. 9 is a diagram illustrating a method for manufacturing the ultrasonic transmission / reception unit 20 according to the second embodiment.
In the present embodiment, the substrate 21 on which the piezoelectric elements 22 are stacked is manufactured as in the first embodiment.
Thereafter, as shown first in FIG. 9, the material for forming the inner acoustic layer 231 is discharged by the inkjet device 95 to the recess 21 </ b> C corresponding to, for example, the third transducer Tr <b> 3 in the recess 21 </ b> C of the substrate 21. And fill. The diameter of the droplet of the forming material of the inner acoustic layer 231 ejected by the ink jet device 95 is sufficiently small with respect to the opening width dimension (for example, 30 μm) of the recess 21C, and the inside acoustic layer 231 and the recess 21C Generation of bubbles at the boundary is suppressed.

  Thereafter, as shown second in FIG. 9, the substrate 21 is tilted by the angle α to solidify the material for forming the inner acoustic layer 231. Thereby, the inner acoustic layer 231 of the third transducer Tr3 is formed.

Next, as shown in the third part of FIG. 9, the substrate 21 is returned to the horizontal position, and the material for forming the inner acoustic layer 231 is filled into the recess 21C corresponding to the second transducer Tr2 by the ink jet device 95. Let And as shown in the 4th of FIG. 9, the board | substrate 21 is inclined by angle-(alpha) and the inner side acoustic layer 231 is solidified. Thereby, the inner acoustic layer 231 of the second transducer Tr2 is formed.
Thereafter, as shown in the fifth part of FIG. 9, the material for forming the inner acoustic layer 231 is discharged and filled into the recess 21 </ b> C corresponding to the first transducer Tr <b> 1 by the ink jet device 95. And as shown in the 6th of FIG. 9, the board | substrate 21 is maintained horizontally and the inner side acoustic layer 231 is solidified. Thereby, the inner acoustic layer 231 of the first transducer Tr1 is formed.

After the above, the outer acoustic layer 232 is applied on the inner acoustic layer 231 as in the first embodiment. As a result, as shown in the seventh part of FIG. 9, the ultrasonic transmission / reception unit 20 including the first transducer Tr1, the second transducer Tr2, and the third transducer Tr3 is manufactured.
In the above example, the inner acoustic layer 231 is formed in the order of the third transducer Tr3, the second transducer Tr2, and the first transducer Tr1, but this is not restrictive. For example, the inner acoustic layer 231 may be formed in the order of the first transducer Tr1, the second transducer Tr2, and the third transducer Tr3, and may be in any order.

[Operational effects of this embodiment]
In the present embodiment, after the material for forming the inner acoustic layer 231 is discharged and filled into the recess 21C from the inkjet device 95, the inner acoustics of the second transducer Tr2 and the third transducer Tr3 are tilted by tilting the substrate 21. Layer 231 is formed.
Thereby, the surface accuracy of the interface 233 of the inner acoustic layer 231 can be improved, and the yield can be improved. That is, as in the first embodiment described above, in the grinding process using the dicer 90, the surface accuracy of the interface 233 decreases due to foreign matters such as grinding dust generated during grinding. In the first embodiment, after the grinding process, the forming material of the inner acoustic layer 231 is thinly coated to make the interface 233 a smooth surface. However, the number of steps for performing the coating increases. On the other hand, in this embodiment, since the grinding process is not accompanied, the foreign matter does not adhere to the interface 233, and the surface accuracy can be improved without performing the coating process or the like.

[Third embodiment]
Next, a third embodiment will be described.
In the first embodiment, an example in which the same forming material is used as the inner acoustic layer 231 filled in the recess 21C has been described. On the other hand, this embodiment differs from the first embodiment in that the second transducer Tr2 and the third transducer Tr3 use the inner acoustic layer 231 of a different material.

FIG. 10 is a cross-sectional view showing a schematic configuration of the ultrasonic transmission / reception unit 20A of the present embodiment. FIG. 11 is a diagram illustrating the transmission direction of ultrasonic waves in the ultrasonic transmission / reception unit 20A of the present embodiment, and FIG. 12 illustrates the ultrasonic transmission / reception unit 20A from the direction inclined with respect to the normal direction of the bottom surface 212A1. It is a figure which shows the propagation path of the ultrasonic wave at the time of receiving a sound wave.
Here, in the present embodiment, the recess 21C in which the second transducer Tr2 is disposed is referred to as a first recess 21C1, and the recess 21C in which the third transducer Tr3 is disposed is referred to as a second recess 21C2.

  In the present embodiment, the first inner acoustic layer 231A filled in the first recess 21C1 and the second inner acoustic layer 231B filled in the second recess 21C2 are made of different materials. Specifically, the velocity of the ultrasonic wave propagating through the first inner acoustic layer 231A is larger than the velocity of the ultrasonic wave propagating through the outer acoustic layer 232, as in the first embodiment. On the other hand, the speed of the ultrasonic wave propagating through the second inner acoustic layer 231 </ b> B is smaller than the speed of the ultrasonic wave propagating through the outer acoustic layer 232.

In the present embodiment, the interface 233 of the first inner acoustic layer 231A, similarly to the first embodiment, inclined at an angle α with respect to the reference plane S _0. Further, the interface 233 of the second inner acoustic layer 231B also, similarly to the first inner acoustic layer 231A, inclined at an angle α with respect to the reference plane _{S 0.}

  Note that the first transducer Tr1 may be filled with the first inner acoustic layer 231A or the second inner acoustic layer 231B. As shown in FIG. The inner acoustic layer 231 made of a material different from 231A and the second inner acoustic layer 231B may be filled.

In such an ultrasonic transmission / reception unit 20A, in the transmission mode, as shown in FIG. 11, the ultrasonic waves transmitted from the first transducer Tr1 propagate along the first direction D1, and are transmitted from the second transducer Tr2. The transmitted ultrasonic wave propagates along the second direction D2.
On the other hand, the sound velocity in the second inner acoustic layer 231B is smaller than the sound velocity in the outer acoustic layer 232, but the inclination direction of the interface 233 is the same inclination direction as the first inner acoustic layer 231A. Therefore, as shown in FIG. 11, the ultrasonic transmission direction in the third transducer Tr3 is inclined to the −X side with respect to the ultrasonic transmission direction (first direction D1) in the first transducer Tr1. . When the speed of sound in the target to which the ultrasonic wave is propagated from the ultrasonic transmitting / receiving unit 20A is larger than that of the outer acoustic layer 232, the transmission direction of the ultrasonic wave in the third transducer Tr3 is further inclined to the −X side (first Four directions D4).

The same applies to the reception mode, and the ultrasonic wave incident from the first direction D1 is suitably received by the first transducer Tr1 as in the first embodiment. On the other hand, in the second transducer Tr2 and the third transducer Tr3, the ultrasonic wave is refracted at the interface 233, so that the ultrasonic wave propagated to the vibration unit 212A is small and the signal value of the detection signal is small. .
As shown in FIG. 12, for example, when an ultrasonic wave is input from the fourth direction D4, the ultrasonic wave is input from the normal direction of the bottom surface 212A1 to the vibrating portion 212A of the third transducer Tr3. On the other hand, in the first transducer Tr1 and the second transducer Tr2, since the ultrasonic wave is refracted by the interface 233 and the ultrasonic wave reaching the vibration unit 212A is reduced, the output signal value is output from the third transducer Tr3. It becomes smaller than the signal value.
Although illustration is omitted, the same applies to the case where an ultrasonic wave is input from the second direction D2. In this case, the signal value from the second transducer Tr2 is obtained from the first transducer Tr1 or the third transducer Tr3. Also grows.

[Operational effects of this embodiment]
In the present embodiment, the first inner acoustic layer 231A filled in the first recess 21C1 and the second inner acoustic layer 231B filled in the second recess 21C2 are made of different materials, respectively, and the first inner acoustic layer The sound speed at 231A is different from the sound speed at the second inner acoustic layer 231B. The normal direction of the interface 233 of the first inner acoustic layer 231A and the normal direction of the interface 233 of the second inner acoustic layer 231B are the same direction, and each is inclined with respect to the normal direction of the bottom surface 212A1. ing.
In such a configuration, as in the first embodiment, it is possible to transmit and receive ultrasonic waves in the second direction D2 and the fourth direction D4 in addition to the first direction D1, and even when a side lobe occurs, the direction A reduction in resolution can be suppressed.

Further, the interface 233 of the first inner acoustic layer 231A and the interface 233 of the second inner acoustic layer 231B is at the same angle alpha, it is inclined with respect to the reference plane _{S 0.} In this case, as in the second embodiment, when the ultrasonic transmission / reception unit 20A is manufactured by the inkjet method, the first inner acoustic layer 231A is provided in the first recess 21C1 and the second recess 21C2 is provided in the second recess 21C2. After filling the inner acoustic layer 231B, the substrate 21 is solidified by being inclined at an angle of −α. Thereby, the first inner acoustic layer 231A and the second inner acoustic layer 231B can be formed at the same time, and the manufacturing efficiency can be improved.

[Fourth embodiment]
Next, an electronic apparatus to which the ultrasonic sensor 10 according to the first to third embodiments described above is applied will be described.

[Moving object to which ultrasonic sensor 10 is applied]
FIG. 13 is a perspective view showing a schematic configuration of a moving body (automobile 101) as an electronic apparatus to which the ultrasonic sensor 10 is applied.
In this application example, the ultrasonic sensor 10 is provided in the bumper 102 of the automobile 101. For example, the ultrasonic sensor 10 transmits ultrasonic waves to the surroundings of the automobile 101 (for example, front, back, left, and right), and detects ultrasonic waves reflected by an obstacle existing around the automobile 101.

In the automobile 101, an electronic control unit 104 (control unit) is provided on the vehicle body 103. The electronic control unit 104 detects obstacles around the automobile 101 based on the detection signal input from the ultrasonic sensor 10 and performs various processes such as a danger avoidance process. For example, based on the detection signal from the ultrasonic sensor 10, automatic driving (unmanned driving) of the automobile 101 is supported. For example, the electronic control unit 104 urgently stops the movement of the automobile 101 when an obstacle within a predetermined distance is detected.
Further, when the electronic control unit 104 detects an obstacle based on the detection signal from the ultrasonic sensor 10 when the automobile 101 is moved backward, the electronic control unit 104 may output notification information (sound, image, etc.) to notify the danger. Good.
At this time, as described above, the ultrasonic sensor 10 can set a wide-angle range including proximity as an ultrasonic transmission / reception range, and can reduce the influence of side lobes. Therefore, the electronic control unit 104 can more accurately detect in which direction an obstacle is present in automatic driving or danger notification in the automobile 101.

The example shown in FIG. 13 is an example of the automobile 101, but can be applied to an aircraft, a ship, a submersible craft, and the like.
For example, in ships, submersibles, and the like, it is possible to avoid the danger of grounding and the like by providing the ultrasonic sensor 10 at the front end in the advancing direction such as the bow and detecting the seabed and rock walls. It is also possible to detect a school of fish on a fishing boat or the like.

[Robot to which the ultrasonic sensor 10 is applied]
FIG. 14 is a perspective view illustrating a schematic configuration of a robot 110 (for example, an industrial robot) as an electronic apparatus to which the ultrasonic sensor 10 is applied.
The robot 110 is a robot that includes a main body 111, an arm 112, and a hand 113. This robot 110 is for industrial use, for example, the arm unit 112 moves the hand unit 113 to a predetermined position, and the hand unit 113 performs predetermined processing (for example, gripping or processing of the work target) on the work target. It is a robot.
In the robot 110, for example, the ultrasonic sensor 10 and the control unit 114 are provided in the main body 111, and the position of the work target is detected by the ultrasonic sensor 10 to move the arm unit 112 and perform processing by the hand unit 113. Control.
At this time, as described above, the ultrasonic sensor 10 can set a wide-angle range including proximity as an ultrasonic transmission / reception range, and can reduce the influence of side lobes. Therefore, the control unit 114 can accurately detect the position of the work target and obstacles around the work target. As a result, the arm unit 112 and the hand unit 113 can be moved so as not to collide with the work target or an obstacle, and the hand unit 113 can perform an appropriate process on the work target.

[Ultrasonic diagnostic apparatus to which the ultrasonic sensor 10 is applied]
FIG. 15 is a diagram illustrating a schematic configuration of an ultrasonic diagnostic apparatus 120 as an electronic apparatus to which the ultrasonic sensor 10 is applied.
The ultrasonic diagnostic apparatus 120 includes an ultrasonic probe 121 and a control device 122 (control unit) that controls the ultrasonic probe 121.
The ultrasonic probe 121 stores the ultrasonic sensor 10, and the ultrasonic measurement of the measurement target is performed by bringing the ultrasonic probe 121 into contact with the measurement target. Then, based on the ultrasonic measurement result input from the ultrasonic sensor 10, the control device 122 forms and displays an internal tomographic image of the measurement target, for example.
At this time, as described above, the ultrasonic sensor 10 can set a wide-angle range including proximity as an ultrasonic transmission / reception range, and can reduce the influence of side lobes. Therefore, the control device 122 can display a highly accurate internal tomographic image in which the influence of the side lobe is reduced (so-called artifacts are suppressed) based on the received signal from the ultrasonic probe 121.

[Modification]
Note that the present invention is not limited to the above-described embodiments and modifications, and a configuration obtained by appropriately combining modifications, improvements, and embodiments within a range in which the object of the present invention can be achieved. Is included.

For example, in the first embodiment, an example in which the sound speed in the inner acoustic layer 231 is larger than the sound speed in the outer acoustic layer 232 is shown, but the present invention is not limited to this.
That is, the sound speed at the inner acoustic layer 231 may be smaller than the sound speed at the outer acoustic layer 232. In this case, the direction of ultrasonic waves that can be transmitted and received by the second transducer Tr2 is the third direction D3, and the direction of ultrasonic waves that can be transmitted and received by the third transducer Tr3 is the second direction D2. Therefore, the azimuth | direction resolution in the ultrasonic sensor 10 can be improved like the said embodiment.

In the first to third embodiments described above, the acoustic layer 23 includes the inner acoustic layer 231 and the outer acoustic layer 232. However, the configuration is not limited thereto. For example, the outer acoustic layer 232 may not be provided.
In this case, although the transmission / reception direction of the ultrasonic wave changes depending on the sound velocity in the medium through which the ultrasonic wave is propagated from the ultrasonic sensor 10, ultrasonic waves from multiple directions can be detected as in the above embodiments. Therefore, the influence of the side lobe can be suppressed and the azimuth resolution can be improved.

  Further, the ultrasonic transmission / reception units 20 and 20 </ b> A may include an acoustic lens on the opposite side of the acoustic layer 23 from the substrate 21. As the acoustic lens, for example, a cylindrical shape having a central axis parallel to the X direction having a circular arc surface in the YZ section can be used. In this case, the ultrasonic waves can be transmitted and received so that the ultrasonic waves transmitted from the respective transmission / reception columns Ch are converged to the center position in the Y direction.

  In 1st embodiment, although the sound speed in the outer acoustic layer 232 showed an example smaller than the sound speed in the object to which an ultrasonic wave is propagated, it is not limited to this. The speed of sound in the outer acoustic layer 232 may be greater than the speed of sound in the target through which the ultrasonic waves are propagated (for example, when transmitting ultrasonic waves in the air). In this case, the inclination angle of the second direction D2 with respect to the first direction D1 or the third direction with respect to the first direction D1 depending on the difference between the speed of sound in the target through which the ultrasonic waves are propagated and the speed of sound in the outer acoustic layer 232. Although the inclination angle of D3 is small, the azimuth resolution can be improved as compared with the ultrasonic sensor provided with only the first transducer Tr1.

In the first embodiment, by using different materials for the inner acoustic layer 231 and the outer acoustic layer 232, a configuration in which the sound velocity in the inner acoustic layer 231 and the sound velocity in the outer acoustic layer 232 are different is illustrated. However, it is not limited to this. For example, the same material (for example, silicone resin) is used as the inner acoustic layer 231 and the outer acoustic layer 232, and fillers (for example, silica, zinc oxide, zirconium oxide, alumina, titanium oxide, silicon carbide, aluminum nitride, carbon) are used in the material. Etc.). Then, the inner acoustic layer 231 and the outer acoustic layer 232 are made different in the sound velocity in the inner acoustic layer 231 and the sound velocity in the outer acoustic layer 232 by changing the filler content, the average particle size of the filler, and the like. It is good also as a structure to allow.
The same applies to the first inner acoustic layer 231A and the second inner acoustic layer 231B in the third embodiment.

In the first embodiment, the ultrasonic transducers Tr arranged in the Y direction are set as one transmission / reception column Ch, and a one-dimensional array in which a plurality of transmission / reception columns Ch are arranged in the X direction is illustrated. It may be configured in a two-dimensional array.
In this case, a drive terminal 221A is provided for each of the lower electrodes 221 of each ultrasonic transducer Tr arranged in the XY directions. That is, the ultrasonic transducer Tr may be driven independently.
In this case also, by ultrasonic transducer Tr having an inner acoustic layer having a surface which is inclined parallel and the reference plane S ₀ in the Y direction (second transducer Tr2 and the third transducer Tr3) is provided, ultrasonic Can be expanded with respect to the X direction. Further, it is preferable to further provide constituting the ultrasonic transducer Tr having an inner acoustic layer having a surface inclined with respect to parallel and the reference plane S ₀ in the X direction. Thereby, the transmission / reception direction of an ultrasonic wave can be extended also to a Y direction, and the influence of a side lobe can be reduced more.

  In the fourth embodiment, the mobile body (the automobile 101), the robot 110, and the ultrasonic diagnostic apparatus 120 are exemplified as the electronic devices to which the ultrasonic sensor 10 is applied. The present invention can be applied to any electronic device that performs processing.

  In addition, the specific structure for carrying out the present invention may be configured by appropriately combining the above-described embodiments and modifications within the scope that can achieve the object of the present invention, and may be appropriately changed to other structures and the like. May be.

DESCRIPTION OF SYMBOLS 10 ... Ultrasonic sensor, 20 and 20A ... Ultrasonic transmission / reception part, 21 ... Board | substrate, 21A ... 1st surface, 21B ... 2nd surface, 21C ... Recessed part, 21C1 ... 1st recessed part, 21C2 ... 2nd recessed part, 22 ... Piezoelectric Element: 23 ... Acoustic layer, 101 ... Automobile (electronic device), 104 ... Electronic control unit (control unit), 110 ... Robot (electronic device), 114 ... Control unit, 120 ... Ultrasonic diagnostic apparatus (electronic device), 121 DESCRIPTION OF SYMBOLS ... Ultrasonic probe, 122 ... Control apparatus (control part), 211 ... Base part, 211A ... Through-hole, 211B ... Wall part, 212 ... Support film, 212A ... Vibrating part, 221 ... Lower electrode, 221A ... Drive terminal, 222 ... Piezoelectric film, 223 ... upper electrode, 231 ... inner acoustic layer, 231A ... first inner acoustic layer, 231B ... second inner acoustic layer, 232 ... outer acoustic layer, 233 ... interface, D1 ... first direction, D2 ... second direction D3 ... third direction, D4 ... fourth direction, S 0 _... reference plane, Tr ... ultrasonic transducer, Tr1 ... first transducer, Tr2 ... second transducer, Tr3 ... third transducer, alpha ... tilt angle .

Claims (6)

A substrate in which a surface provided with a plurality of recesses and a surface provided with a plurality of ultrasonic elements are opposite to each other;
An acoustic layer filled in the recess,
When viewed from the thickness direction of the substrate, the ultrasonic element is provided at a position overlapping the recess,
The ultrasonic sensor, wherein an interface of the acoustic layer facing the bottom surface of the concave portion is inclined with respect to the bottom surface of the concave portion. The ultrasonic sensor according to claim 1,
The plurality of recesses include a first recess and a second recess,
An ultrasonic sensor characterized in that the speed of sound propagating in the acoustic layer filled in the first recess is different from the speed of sound propagating in the acoustic layer filled in the second recess. The ultrasonic sensor according to claim 1 or 2,
The acoustic layer includes an acoustic layer filled in the recess and an acoustic layer stacked on the opposite side of the bottom surface of the recess,
The ultrasonic sensor characterized in that the sound velocity propagating through the inside of the acoustic layer laminated on the side opposite to the bottom surface of the recess is different from the sound velocity propagating through the inside of the acoustic layer filled in the recess. The ultrasonic sensor according to claim 2,
The ultrasonic sensor, wherein the acoustic layer filled in the first recess and the acoustic layer filled in the second recess are made of different materials. The ultrasonic sensor according to claim 3.
The ultrasonic sensor, wherein the acoustic layer filled in the recess and the acoustic layer laminated on the side opposite to the bottom surface of the recess are made of different materials. The ultrasonic sensor according to any one of claims 1 to 5,
A control unit for controlling the ultrasonic sensor;
An electronic device characterized by comprising:

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