JP2020155919A - Ultrasonic sensor - Google Patents

Abstract

To provide an ultrasonic sensor which is high in inspection accuracy and excellent in inspection efficiency.SOLUTION: An ultrasonic sensor according to an embodiment of the present invention includes: a vibration detection element 2 having a plurality of vibration detection parts 2a; and a coating layer 3 to be laminated on the vibration detection element 2. The coating layer 3 has a plurality of ultrasonic transmission parts 3a overlapping with the plurality of vibration detection parts 2a.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ultrasonic sensor.

Ultrasonic sensors are used to inspect the heat sealability of food packages. This ultrasonic sensor is placed facing the ultrasonic transmitter with the subject in between, and inspects the adhesive state of the heat seal by detecting the ultrasonic waves transmitted from the ultrasonic transmitter and transmitted through the subject. It is configured to be possible (see Japanese Patent Application Laid-Open No. 2013-127400).

Japanese Unexamined Patent Publication No. 2013-127400

The ultrasonic sensor described in the above publication is arranged so as to be in focus with the ultrasonic transmitter. It is said that this ultrasonic sensor can inspect the adhesive state of the subject with high accuracy by arranging the subject in focus.

However, this ultrasonic sensor can inspect the adhesive state of the subject only at one place. Therefore, this ultrasonic sensor takes time and effort to inspect the adhesive state of the subject in a wide range.

The present invention has been made based on such circumstances, and an object of the present invention is to provide an ultrasonic sensor having high inspection accuracy and excellent inspection efficiency.

The ultrasonic sensor according to one aspect of the present invention, which has been made to solve the above problems, includes a vibration detection element having a plurality of vibration detection units and a coating layer laminated on the vibration detection element, and the coating layer is provided. However, it has a plurality of ultrasonic wave transmitting units that overlap with the plurality of vibration detecting units.

It is preferable that the ultrasonic wave transmitting portion is a through hole.

It is preferable that the coating layer is a flexible resin film.

The average thickness of the portion of the coating layer other than the ultrasonic wave transmitting portion in the region laminated on the vibration detection element is preferably 0.5 mm or more and 5 mm or less.

The vibration detection element has a film-shaped piezoelectric body and a pair of electrodes laminated on both surfaces of the piezoelectric body, and at least one of the electrodes is divided into a plurality of pieces corresponding to the plurality of vibration detection units. It is preferable that the coating layer is laminated on one of the electrode sides.

The average distance between the adjacent vibration detection units is preferably 0.5 mm or more and 2.0 mm or less.

It is preferable that the plurality of vibration detection units are arranged in a grid pattern.

In the present invention, the "average thickness" means the average value of the thicknesses of any 10 points. The "average interval" means the average value of the intervals of any five points. "A plurality of vibration detection units are arranged in a grid point pattern" means that a plurality of vibration detection units are arranged at positions corresponding to the grid points.

Since the ultrasonic sensor according to one aspect of the present invention includes a vibration detection element having a plurality of vibration detection units, it is possible to simultaneously inspect a plurality of locations of a subject. Further, the ultrasonic sensor has a plurality of ultrasonic wave transmitting portions in which the coating layer laminated on the vibration detecting element overlaps with the plurality of vibration detecting portions, and ultrasonic waves in regions other than these ultrasonic transmitting portions. Permeation can be suppressed. Therefore, the ultrasonic sensor can suppress crosstalk between a plurality of vibration detection units. Therefore, the ultrasonic sensor has high inspection accuracy and excellent inspection efficiency.

FIG. 1 is a schematic side sectional view showing an ultrasonic sensor according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the ultrasonic sensor of FIG. FIG. 3 is a sectional view taken along line AA of the ultrasonic sensor of FIG. FIG. 4 is a schematic perspective view showing an ultrasonic sensor according to an embodiment different from the ultrasonic sensor of FIG. FIG. 5 is a schematic side sectional view showing a modified example of the coating layer. FIG. 6 is a schematic side sectional view showing a modified example of the coating layer different from that of FIG. 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[First Embodiment]
<Ultrasonic sensor>
The ultrasonic sensor 1 of FIGS. 1 and 2 includes a vibration detection element 2 having a plurality of vibration detection units 2a, and a coating layer 3 laminated on the vibration detection element 2. The coating layer 3 has a plurality of ultrasonic wave transmitting portions 3a that overlap with the plurality of vibration detecting portions 2a. The ultrasonic sensor 1 is a two-dimensional array sensor in which a plurality of vibration detection units 2a are formed in the in-plane direction of the vibration detection element 2. The ultrasonic sensor 1 is used, for example, as an inspection device for inspecting the heat sealability of a food package, the presence or absence of air bubbles in a storage battery or a fuel cell, or the like by ultrasonic waves. In the ultrasonic sensor 1, the surface of the vibration detection element 2 constitutes an ultrasonic receiving surface facing an ultrasonic transmitter (not shown) with a subject in between. In the following description, the "front surface" refers to the surface on the ultrasonic wave receiving side, and the "back surface" refers to the surface on the opposite side.

(Vibration detection element)
The vibration detection element 2 is laminated on the film-shaped piezoelectric body 11 and a pair of electrodes laminated on both sides of the piezoelectric body 11 (the first electrode 12a laminated on the surface of the piezoelectric body 11 and the back surface of the piezoelectric body 11). It has a second electrode 12b). The vibration detection element 2 has a sheet shape as a whole.

Examples of the piezoelectric material forming the piezoelectric body 11 include lead zirconate titanate (PZT), lithium niobate (LiNbO ₃ ), potassium tantalate niobate (K (Ta, Nb) O ₃ ), and barium titanate (BaTIO). ₃ ), lithium tantalate (LiTaO ₃ ), strontium tantalate (SrTIO ₃ ), and inorganic piezoelectric materials such as crystal can be mentioned.

Further, as the piezoelectric material, a material having flexibility is also preferably used. This makes it possible to impart flexibility to the piezoelectric body 11. As a result, for example, by bending the piezoelectric body 11 into an arch shape or the like, it is easy to focus the ultrasonic wave transmitting surface of the ultrasonic wave transmitter and the ultrasonic wave receiving surface of the vibration detecting element 2.

Examples of the flexible material include polymer piezoelectric materials. Examples of the polymer piezoelectric material include polyvinylidene fluoride (PVDF), vinylidene fluoride-3 ethylene fluoride copolymer (P (VDF / TrFE)), and vinylidene cyanide-vinyl acetate copolymer (P (VDCN /)). VAc)) and the like can be mentioned. Further, by using these polymer piezoelectric materials as a porous film, the flexibility can be further increased, and the curvature and flexibility of the vibration detection element 2 can be enhanced.

Further, as the flexible material, a large number of flat pores are formed in a synthetic resin such as polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), or polyethylene terephthalate (PET) which does not have piezoelectric properties. It is also possible to use a material in which the facing surface of these pores is polarized and charged by corona discharge or the like to impart piezoelectric characteristics.

When the piezoelectric body 11 has flexibility, the lower limit of the average thickness of the piezoelectric body 11 is preferably 10 μm, more preferably 50 μm. On the other hand, when the piezoelectric body 11 has flexibility, the upper limit of the average thickness of the piezoelectric body 11 is preferably 500 μm, more preferably 200 μm. If the average thickness of the piezoelectric body 11 does not reach the lower limit, the strength of the piezoelectric body 11 may be insufficient. On the contrary, if the average thickness of the piezoelectric body 11 exceeds the upper limit, it may be difficult to form a desired curved or bent shape.

The first electrode 12a and the second electrode 12b are thin films. The first electrode 12a and the second electrode 12b are used to detect the potential difference between the front and back surfaces of the piezoelectric body 11. Therefore, the first electrode 12a and the second electrode 12b are connected to a detection circuit (not shown).

The material of the first electrode 12a and the second electrode 12b may be any material having conductivity, and examples thereof include metals such as aluminum, copper and nickel, carbon and the like.

The method of laminating the first electrode 12a and the second electrode 12b on the piezoelectric body 11 is not particularly limited, and examples thereof include metal deposition, printing of carbon conductive ink, application and drying of silver paste, and the like.

The average thickness of the first electrode 12a and the second electrode 12b may be, for example, 0.1 μm or more and 30 μm or less, although it depends on the laminating method. If the average thickness is less than the lower limit, the strength of the first electrode 12a and the second electrode 12b may be insufficient. On the contrary, if the average thickness exceeds the upper limit, the followability to the curved surface shape in the curved or bent state of the vibration detection element 2 may decrease.

As shown in FIG. 3, the first electrode 12a is divided into a plurality of line-shaped pieces (first fragment 12c). The first fragment 12c is linear. The plurality of first fragment pieces 12c are arranged in parallel. Further, the second electrode 12b is divided into a plurality of line-shaped pieces (second fragment 12d) orthogonal to the plurality of first fragment 12c in a plan view. The second fragment 12d is linear. The plurality of second fragment 12d are arranged in parallel. The plurality of first fragment pieces 12c and the plurality of second fragment pieces 12d partially overlap in a plan view. In the vibration detection element 2, the region where the first fragment 12c and the second fragment 12d overlap in a plan view functions as the vibration detection unit 2a. That is, the first electrode 12a is divided into the first fragment 12c corresponding to each row of the plurality of vibration detection units 2a, and the second electrode 12b is the second corresponding to each row of the plurality of vibration detection units 2a. It is divided into fragment 12d. The vibration detection unit 2a is formed in a two-dimensional array shape because the plurality of first fragment pieces 12c and the plurality of second fragment pieces 12d are orthogonal to each other in a plan view. The vibration detection units 2a formed in a two-dimensional array can independently measure the intensity of ultrasonic waves.

The lower limit of the average interval D between the adjacent vibration detection units 2a is preferably 0.5 mm, more preferably 0.8 mm. On the other hand, the upper limit of the average interval D is preferably 2.0 mm, more preferably 1.5 mm. If the average interval D is less than the lower limit, crosstalk between adjacent vibration detection units 2a may not be sufficiently suppressed. On the contrary, when the average interval D exceeds the upper limit, the interval between the adjacent vibration detection units 2a becomes too large, and it may be difficult to sufficiently improve the detection efficiency.

As shown in FIG. 2, the plurality of vibration detection units 2a are arranged in a grid dot pattern. In other words, the plurality of first fragment pieces 12c and the plurality of second fragment pieces 12d overlap in a grid pattern in a plan view. Specifically, the plurality of vibration detection units 2a are arranged at each grid point of a quadrangular grid, more specifically, a regular quadrangular grid. In the ultrasonic sensor 1, the plurality of vibration detection units 2a are arranged in a grid pattern, so that the plurality of vibration detection units 2a are arranged at high density while suppressing crosstalk between adjacent vibration detection units 2a. It's easy to do. As a result, the ultrasonic sensor 1 can easily improve the inspection efficiency while suppressing the deterioration of the inspection accuracy.

(Coating layer)
The coating layer 3 has a plurality of ultrasonic wave transmitting units 3a that overlap with the plurality of vibration detecting units 2a, and an ultrasonic shielding unit 3b that overlaps with regions other than the plurality of vibration detecting units 2a. The coating layer 3 selectively transmits ultrasonic waves in the thickness direction by a plurality of ultrasonic wave transmitting portions 3a. It is preferable that the number of ultrasonic wave transmitting units 3a and the number of vibration detecting units 2a match. That is, it is preferable that the ultrasonic wave transmitting portion 3a is formed in a one-to-one correspondence with the vibration detecting portion 2a.

The coating layer 3 suppresses crosstalk between the plurality of ultrasonic detection units 2a. Therefore, the coating layer 3 is laminated on the ultrasonic wave receiving surface side of the vibration detection element 2. That is, the coating layer 3 is laminated on the surface side (outer surface side) of the first electrode 12a of the vibration detection element 2. As described above, in the present embodiment, the first electrode 12a is divided into a plurality of first fragment pieces 12c corresponding to the plurality of vibration detection units 2a, and the coating layer 3 is the first electrode of the vibration detection element 2. It is laminated on the 12a side. The coating layer 3 is laminated on the surface side of the plurality of first fragment 12c, so that the ultrasonic waves irradiated to the regions other than the plurality of vibration detection units 2a are irradiated more ultrasonically than the plurality of first fragment 12c. It can be shielded on the upstream side of the direction. As a result, the ultrasonic sensor 1 can suppress interference with the vibration detection unit 2a due to ultrasonic waves irradiating a region other than the plurality of vibration detection units 2a, and can sufficiently suppress crosstalk.

The coating layer 3 is, for example, a resin layer containing a synthetic resin as a main component. Examples of the synthetic resin include polyolefin, polyester, polyamide, polyethylene terephthalate, silicone resin, polyimide and the like. The "main component" refers to the component having the highest content in terms of mass.

The coating layer 3 is preferably a flexible resin film. According to this configuration, a plurality of ultrasonic wave transmitting portions 3a can be easily formed on the coating layer 3. Further, when the vibration detecting element 2 is bent or bent when the piezoelectric body 11 is made of a flexible material, the coating layer 3 can be easily made to follow the shape of the vibration detecting element 2.

When the coating layer 3 is the above-mentioned resin film, the coating layer 3 can be laminated on the vibration detection element 2 with, for example, an adhesive or an adhesive. According to this configuration, an adhesive layer or an adhesive layer is arranged between the coating layer 3 and the vibration detection element 2. These layers are filled, for example, in the region between the plurality of first fragment pieces 12c to increase the adhesion strength between the coating layer 3 and the vibration detecting element 2.

As shown in FIGS. 1 and 2, the ultrasonic wave transmitting portion 3a is a through hole. Since the ultrasonic wave transmitting portion 3a is a through hole, the ultrasonic sensor 1 can easily and highly accurately receive the ultrasonic waves emitted from the ultrasonic transmitter by the plurality of first fractional fragments 12c.

The through hole can be rectangular. As shown in FIGS. 2 and 3, the width W1 of the through hole in the width direction of the plurality of first fragment 12c may be larger than the width W2 of the plurality of first fragment 12c. Further, the width W3 of the through hole in the width direction of the plurality of second fragment 12d may be larger than the width W4 of the plurality of second fragment 12d. According to this configuration, it is easy to visually align the ultrasonic wave transmitting unit 3a so as to correspond to the vibration detecting unit 2a.

The through hole may be formed by, for example, a puncher, or may be formed by etching after patterning the photoresist.

The lower limit of the average thickness T of the portion (that is, the ultrasonic shielding portion 3b) other than the ultrasonic transmitting portion 3a in the region laminated on the vibration detecting element 2 of the coating layer 3 is preferably 0.5 mm, more preferably 1 mm. preferable. On the other hand, as the upper limit of the average thickness T, 5 mm is preferable, and 3 mm is more preferable. If the average thickness T does not reach the lower limit, ultrasonic waves may not be sufficiently shielded. On the contrary, if the average thickness T exceeds the upper limit, the flexibility of the coating layer 3 may be insufficient.

<Advantage>
Since the ultrasonic sensor 1 includes a vibration detection element 2 having a plurality of vibration detection units 2a, it is possible to simultaneously inspect a plurality of locations of the subject. Further, the ultrasonic sensor 1 has a plurality of ultrasonic transmitting portions 3a in which the coating layer 3 laminated on the vibration detecting element 2 overlaps with the plurality of vibration detecting portions 2a, and other than these ultrasonic transmitting portions 3a. It is possible to suppress the transmission of ultrasonic waves in the region of. Therefore, the ultrasonic sensor 1 can suppress crosstalk between a plurality of vibration detection units 2a. Therefore, the ultrasonic sensor 1 has high inspection accuracy and excellent inspection efficiency.

[Second Embodiment]
<Ultrasonic sensor>
The ultrasonic sensor 21 of FIG. 4 includes a vibration detection element 22 having a plurality of vibration detection units 22a, and a coating layer 23 laminated on the vibration detection element 22. The coating layer 23 is laminated on the surface side of the vibration detection element 22. Further, the ultrasonic sensor 21 includes a base 24 that supports the vibration detection element 22 from the back surface side. The coating layer 23 has a plurality of ultrasonic wave transmitting portions 23a that overlap with the plurality of vibration detecting portions 22a. The ultrasonic sensor 21 is an array sensor in which a plurality of vibration detection units 22a are formed in the in-plane direction of the vibration detection element 22. The ultrasonic sensor 21 is used, for example, as an inspection device for inspecting the heat sealability of a food package, the presence or absence of air bubbles in a storage battery or a fuel cell, or the like by ultrasonic waves. In the ultrasonic sensor 21, the surface of the vibration detection element 22 constitutes an ultrasonic receiving surface facing an ultrasonic transmitter (not shown) with a subject in between.

(Vibration detection element)
The vibration detection element 22 is laminated on the film-shaped piezoelectric body 31 and a pair of electrodes laminated on both sides of the piezoelectric body 31 (the first electrode 32a laminated on the surface of the piezoelectric body 31 and the back surface of the piezoelectric body 31). It has a second electrode 32b). The vibration detection element 22 has a sheet shape as a whole. The vibration detection element 22 is held in an arched state by being supported by the base 24 on the back surface side.

As the piezoelectric material for forming the piezoelectric body 31, a flexible material is used. Examples of the flexible material include the above-mentioned polymer piezoelectric material and a synthetic resin having no piezoelectric property in which a large number of flat pores are formed and the facing surfaces of the pores are polarized and charged. Be done.

The first electrode 32a and the second electrode 32b are thin films. The materials of the first electrode 32a and the second electrode 32b can be the same as those of the first electrode 12a and the second electrode 12b in FIG.

The average thickness of the piezoelectric body 31 and the average thickness of the first electrode 32a and the second electrode 32b can be the same as those of the vibration detection element 2 of the ultrasonic sensor 1 of FIG.

The first electrode 32a is divided into a plurality of pieces (first fragment 32c). On the other hand, the second electrode 32b is laminated as one thin film body on the back surface of the piezoelectric body 31 so as to include the plurality of first fragment pieces 32c in a plan view. In the vibration detection element 22, the region where the first electrode 32a and the second electrode 32b overlap in the thickness direction of the piezoelectric body 31 functions as the vibration detection unit 22a. That is, the first fragment 32c of the first electrode 32a corresponds to the vibration detection unit 22a in the body 1.

The vibration detection unit 22a (that is, the first fragment 32c) is linear. The longitudinal directions of the plurality of vibration detection units 22a are parallel. That is, the plurality of vibration detection units 22a are arranged in a stripe shape. More specifically, the plurality of vibration detection units 22a are arranged in parallel in the width direction in a state of being curved in an arch shape along the longitudinal direction. The average distance between the adjacent vibration detection units 22a can be the same as the average distance D between the adjacent vibration detection units 2a of the ultrasonic sensor 1 in FIG.

(Coating layer)
The coating layer 23 has a plurality of ultrasonic wave transmitting units 23a that overlap with the plurality of vibration detecting units 22a, and an ultrasonic shielding unit 23b that overlaps with regions other than the plurality of vibration detecting units 22a. The ultrasonic wave transmitting portion 23a is a through hole. It is preferable that the number of ultrasonic wave transmitting units 23a and the number of vibration detecting units 22a match. That is, it is preferable that the ultrasonic wave transmitting portion 23a is formed in a one-to-one correspondence with the vibration detecting portion 22a. The ultrasonic wave shielding portions 23b arranged so as to sandwich the ultrasonic wave transmitting portion 23a may be partially connected so that the positional relationship with respect to the vibration detecting element 22 is fixed.

The coating layer 23 is laminated on the ultrasonic wave receiving surface side of the vibration detection element 22. In the present embodiment, the first electrode 32a is divided into a plurality of first fragment 32c corresponding to the plurality of vibration detection units 22a, and the coating layer 23 is laminated on the first electrode 32a side.

The specific configuration of the coating layer 23 can be the same as that of the coating layer 3 of FIG. 1 except that the shape of the ultrasonic wave transmitting portion 23a is formed in a stripe shape corresponding to the vibration detecting portion 22a. For example, the coating layer 23 can be a flexible resin film. The average thickness of the ultrasonic shielding portion 23b of the coating layer 23 can be the same as that of the coating layer 3 of FIG. The ultrasonic shielding portion 23b may be formed to the outside of the side edge of the piezoelectric body 31. As a result, it is possible to suppress the wraparound of ultrasonic waves to the back surface side of the vibration detection element 22. Further, according to this configuration, the ultrasonic shielding portion 23b sandwiched between the ultrasonic transmitting portions 23a can be easily and integrally held by connecting them on the outside of the piezoelectric body 31.

(Base)
The base 24 is a base that holds the vibration detection element 22. The surface shape of the base 24 is formed, for example, corresponding to the shape of the ultrasonic wave transmitting surface of the ultrasonic wave transmitter. In the present embodiment, the surface of the base 24 has an arch shape with a recessed central portion.

As the material of the base 24, a material having conductivity such as metal can be used, but a material having insulation is preferable. When the base 24 has an insulating property, examples of the main component of the base 24 include synthetic resins such as polyethylene terephthalate and polypropylene.

<Advantage>
Since the ultrasonic sensor 21 is arranged in parallel in the width direction in a state where the plurality of vibration detection units 22a are curved in an arch shape along the longitudinal direction, the focus is on the ultrasonic reception surface of the vibration detection element 22. It is possible to receive a wide area of ultrasonic waves emitted from the ultrasonic transmitter so as to converge on the subject in a state where the focal point of the ultrasonic transmitting surface of the ultrasonic transmitter is aligned. As a result, the ultrasonic sensor 21 can easily improve the inspection accuracy.

[Other Embodiments]
The embodiment does not limit the configuration of the present invention. Therefore, it is possible to omit, replace or add components of each part of the embodiment based on the description of the present specification and common general technical knowledge, and all of them are construed to belong to the scope of the present invention. Should be.

A modified example of the coating layer will be described with reference to FIGS. 5 and 6. The coating layer 43 of FIG. 5 is a resin film in which a material is directly patterned on the surface of the piezoelectric body 11. According to this configuration, after the entire surface of the piezoelectric body 11 is coated with a synthetic resin, a through hole 43a (ultrasonic wave transmitting portion) can be easily formed in accordance with the vibration detecting portion 42a by a photoresist. Further, the coating layer 43 may be formed by patterning a synthetic resin by a printing method such as screen printing. In this case, the cross section of the through hole 43a in the depth direction is not vertical, and the diameter of the end portion on the piezoelectric body 11 side can be reduced (that is, the skirt is provided at the end portion of the ultrasonic shielding portion 43b on the piezoelectric body 11 side. Can be formed). The coating layer 43 contains a synthetic resin as a main component and has flexibility. The ultrasonic shielding portion 43b may be partially laminated on the first electrode 44a.

The coating layer 53 of FIG. 6 has a plurality of through holes 53a (ultrasonic wave transmitting portions) whose diameters are expanded in a reverse taper shape toward the ultrasonic wave transmitter side. According to this configuration, since the ultrasonic wave incident side is widened, it is possible to efficiently measure ultrasonic waves while preventing crosstalk.

The ultrasonic sensor may form an alignment mark so that the coating layer can be easily aligned with the vibration detection element. For example, in the ultrasonic sensor, a circular pattern in a plan view is formed at four corners of the piezoelectric body by the first electrode, and through holes having a diameter larger than these patterns are formed at positions corresponding to these patterns in the coating layer. You may. According to this configuration, the vibration detection element and the coating layer can be easily aligned by confirming the position of the pattern through the through hole of the coating layer. Further, in the ultrasonic sensor, if through holes can be formed in the piezoelectric body, through holes are formed in the four corners of the piezoelectric body, and alignment marks corresponding to these through holes are formed in the coating layer. May be good. The arrangement, shape, etc. of the alignment mark are not particularly limited. For example, the plan view shape of the pattern may be a polygonal shape, a cross shape, an X shape, or the like.

As the ultrasonic wave transmitting portion, it is possible to adopt a configuration other than the through hole. For example, the ultrasonic wave transmitting portion may be a thin-walled portion having a thickness smaller than that of the ultrasonic shielding portion. Further, the ultrasonic wave transmitting portion may be made of a material having a higher ultrasonic wave transmittance than the ultrasonic shielding portion.

The arrangement of the plurality of vibration detection units can be set according to the purpose of use and the like, and is not limited to the above-mentioned lattice point shape and stripe shape. Further, even when the plurality of vibration detection units are arranged in a grid pattern, these vibration detection units may be arranged at positions corresponding to grid points having a grid shape other than a quadrangular grid.

As described above, the ultrasonic sensor according to one aspect of the present invention has high inspection accuracy and excellent inspection efficiency, and is therefore suitable for inspecting the heat sealability of a food package.

1,21 Ultrasonic sensor 2,22 Vibration detection element 2a, 22a, 42a Vibration detection unit 3,23,43,53 Coating layer 3a, 23a Ultrasonic transmission unit 3b, 23b, 43b Ultrasonic shielding unit 11,31 Piezoelectric material 12a, 32a, 44a 1st electrode 12b, 32b 2nd electrode 12c, 32c 1st fragment 12d 2nd fragment 24 Base 43a, 53a Through hole

Claims (7)

A vibration detection element having multiple vibration detection units and
A coating layer laminated on the vibration detection element is provided.
An ultrasonic sensor having a plurality of ultrasonic wave transmitting portions in which the coating layer overlaps the plurality of vibration detecting portions. The ultrasonic sensor according to claim 1, wherein the ultrasonic wave transmitting portion is a through hole. The ultrasonic sensor according to claim 1 or 2, wherein the coating layer is a flexible resin film. The super-superior according to claim 1, claim 2 or claim 3, wherein the average thickness of the portion of the coating layer other than the ultrasonic wave transmitting portion in the region laminated on the vibration detection element is 0.5 mm or more and 5 mm or less. Sound wave sensor. The vibration detection element has a film-shaped piezoelectric body and a pair of electrodes laminated on both surfaces of the piezoelectric body, and at least one of the electrodes is divided into a plurality of pieces corresponding to the plurality of vibration detection units. The ultrasonic sensor according to any one of claims 1 to 4, wherein the coating layer is laminated on one of the electrode sides. The ultrasonic sensor according to any one of claims 1 to 5, wherein the average distance between adjacent vibration detection units is 0.5 mm or more and 2.0 mm or less. The ultrasonic sensor according to any one of claims 1 to 6, wherein the plurality of vibration detection units are arranged in a grid pattern.

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