Package, ultrasonic sensor, and multi-feed detection device

Abstract

To provide a mounting body, an ultrasonic sensor, and a double feed detection device capable of improving productivity.SOLUTION: The circuit substrate 100 includes the first wiring layer 130 electrically coupled to the circuit unit 110, the element substrate 200 includes the first substrate 210, the vibrating plate 240, the piezoelectric element, the second substrate 220, and the second wiring layer 230 electrically coupled to the piezoelectric element, and includes the third wiring layer 330 that electrically couples the first wiring layer 130 and the second wiring layer 230, and the protective member 310 that covers the third wiring layer 330.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a mount assembly, an ultrasonic sensor, and a double feed detection device. [Background technology]

[0002] Patent Document 1 discloses a configuration in which, when mounting an IC chip on a substrate, a conductive material is formed in a coating form around the outer periphery of a plastic material, and the plastic material acts to provide cushioning properties, thereby absorbing variations in the height direction and achieving good mounting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-151508 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, when the plastic material is hardened by heat treatment or the like after the IC chip is mounted on the substrate, the heat treatment must be performed for each IC chip, which poses a problem of low productivity. [Means for solving the problem]

[0005] the mounting body is a mounting body in which an element substrate is mounted on a circuit board, the circuit board comprising: a circuit section; a mounting section in which a holding member for holding the element substrate is arranged and in which the element substrate is mounted; and a first wiring layer electrically connected to the circuit section and one end extending to at least a part of the area surrounding the mounting section; the element substrate comprising: a first substrate having a first surface and a second surface opposite to the first surface and having a first opening formed from the first surface to the second surface; a vibration plate that closes the first surface side of the first opening; a piezoelectric element provided on the surface of the vibration plate opposite to the first opening; a second substrate arranged opposite to the surface of the vibration plate opposite to the first opening and having a space formed therein to accommodate the piezoelectric element; a second wiring layer electrically connected to the piezoelectric element and extending to the outside of the second substrate; and a third wiring layer electrically connecting the first wiring layer and the second wiring layer; and a protective member that covers the third wiring layer.

[0006] The ultrasonic sensor includes the above-described mounting body.

[0007] The double feed detection device includes the ultrasonic sensor described above. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing the configuration of a face-down mounted ultrasonic sensor. [Figure 2] FIG. 2 is a cross-sectional view of the ultrasonic sensor shown in FIG. 1 taken along line AA. [Figure 3] FIG. 2 is a plan view showing the configuration of a circuit board of the ultrasonic sensor. [Figure 4] FIG. 2 is a plan view showing the configuration of an element substrate of the ultrasonic sensor. [Figure 5] FIG. 3 is an enlarged cross-sectional view of part B of the ultrasonic sensor shown in FIG. 2. [Figure 6A] FIG. 2 is a plan view showing the configuration of an ultrasonic sensor. [Figure 6B] FIG. 2 is a plan view showing the configuration of an ultrasonic sensor. [Figure 7] FIG. 2 is an exploded perspective view showing the configuration of an ultrasonic sensor. [Figure 8] FIG. 8 is a cross-sectional view taken along line CC of the ultrasonic sensor shown in FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view taken along line DD of the ultrasonic sensor shown in FIG. 7. [Figure 10] FIG. [Figure 11] FIG. 1 is a cross-sectional view showing the configuration of a face-up mounted ultrasonic sensor. [Figure 12] 12 is an enlarged cross-sectional view of a portion E of the ultrasonic sensor shown in FIG. 11. [Figure 13A] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13B] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13C] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13D] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13E] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13F] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 13G] 5A to 5C are cross-sectional views illustrating a method for manufacturing an ultrasonic sensor. [Figure 14] FIG. 1 is a cross-sectional view showing the configuration of a bonding wire mounted ultrasonic sensor. [Figure 15] 15 is an enlarged cross-sectional view of the portion F of the ultrasonic sensor shown in FIG. 14. [Figure 16A] FIG. 2 is a schematic diagram showing the configuration of a double feed detection device. [Figure 16B] FIG. 2 is a schematic diagram showing the configuration of a double feed detection device. DETAILED DESCRIPTION OF THE INVENTION

[0009] The configuration of an ultrasonic sensor 1000, which is an example of a mounting assembly, and a multi-feed detection device 2000 equipped with the ultrasonic sensor 1000 will be described below with reference to the drawings. In the following drawings, three mutually perpendicular axes will be referred to as the X-axis, Y-axis, and Z-axis. The direction along the X-axis will be referred to as the "X-direction," the direction along the Y-axis will be referred to as the "Y-direction," and the direction along the Z-axis will be referred to as the "Z-direction." The direction of the arrow is the + direction, and the direction opposite to the + direction is referred to as the - direction. Note that a view from the +Z direction or the -Z direction is also referred to as a planar view or planar.

[0010] First, the configuration of an ultrasonic sensor 1000, which is an example of a mounting assembly, will be described with reference to FIGS.

[0011] As shown in FIGS. 1 and 2, the ultrasonic sensor 1000 includes a circuit board 100 and an element substrate 200 mounted on the circuit board 100.

[0012] The circuit board 100 has a circuit section 110, a holding member 120, a mounting section 300, and a first wiring layer 130. The circuit board 100 is made of, for example, a glass epoxy substrate (see FIG. 3).

[0013] The holding members 120 hold the element substrate 200 to the circuit board 100. The holding members 120 are arranged, for example, at the four corners of the element substrate 200. The holding members 120 are made of a holding material with a high viscosity that can withstand the weight of the element substrate 200. In other words, the holding members 120 are used to secure the position of the element substrate 200 relative to the circuit board 100 before electrical conduction between the element substrate 200 and the circuit board 100 is established.

[0014] The mounting section 300 is a section where the circuit board 100 and the element substrate 200 are arranged so as to be electrically conductive to each other. In this embodiment, the mounting section 300 is a section that includes the area where the element substrate 200 is arranged and the periphery of the area where the first wiring layer 130 of the circuit board 100 and the second wiring layer 230 of the element substrate 200 are electrically connected by the third wiring layer 330 (see FIG. 2).

[0015] The first wiring layer 130 is electrically connected to the circuit unit 110. The first wiring layer 130 is arranged to extend to at least a part of the area covering the mounting unit 300. As shown in FIG. 3 , one side of the first wiring layer 130 is arranged to extend to, for example, a first end 100a of the circuit board 100. The other side of the first wiring layer 130 is arranged to extend to, for example, a second end 100b of the circuit board 100.

[0016] The element substrate 200 includes a first substrate 210 , a vibration plate 240 , a piezoelectric element 250 , a second substrate 220 , and a second wiring layer 230 .

[0017] 5, the first substrate 210 has a first surface 210a and a second surface 210b opposite to the first surface 210a. The first substrate 210 has a first opening 211 formed across from the first surface 210a to the second surface 210b.

[0018] The diaphragm 240 is disposed so as to close the first surface 210a side of the first opening 211. The diaphragm 240 vibrates in response to the operation of the piezoelectric element 250, as will be described in detail later.

[0019] The piezoelectric element 250 is provided on a first surface 240a of the vibration plate 240 opposite to the first opening 211. The piezoelectric element 250 is configured by laminating a first electrode 250a, a piezoelectric layer 250b, and a second electrode 250c (see FIG. 8).

[0020] Second substrate 220 is disposed opposite first surface 240a of diaphragm 240 on the opposite side to first opening 211. Second substrate 220 is provided with space 221 for accommodating piezoelectric element 250 therein on the side facing diaphragm 240. In other words, second substrate 220 functions as a sealing plate.

[0021] The second wiring layer 230 is electrically connected to the piezoelectric elements 250. The second wiring layer 230 is arranged to extend to the outside of the second substrate 220 (see FIGS. 4 and 5).

[0022] The first wiring layer 130 arranged on the circuit board 100 and the second wiring layer 230 arranged on the element substrate 200 are electrically connected by a third wiring layer 330 (see FIG. 5). The third wiring layer 330 is, for example, a silver (Ag) paste. The third wiring layer 330 is covered with a protective member 310. An example of the protective member 310 is an epoxy adhesive. The protective member 310 may also be made of urethane resin, epoxy resin, acrylic resin, or the like.

[0023] As described above, one side of the first wiring layer 130 is arranged at the first end 100a of the circuit board 100, and the other side of the first wiring layer 130 is arranged at the second end 100b of the circuit board 100 (see FIG. 6A). For example, the ultrasonic sensor 1000A may have one side arranged at the third end 100c and the other side arranged at the fourth end 100d (see FIG. 6B).

[0024] As described above, the first wiring layer 130 electrically connected to the circuit section 110, the second wiring layer 230 electrically connected to the piezoelectric elements 250, and the third wiring layer 330 electrically connecting the first wiring layer 130 and the second wiring layer 230 are provided, so that, compared to the conventional method of using bumps to harden one element substrate 200 to one circuit substrate 100 by heat treatment, it is possible to simultaneously harden a plurality of element substrates 200 and a plurality of circuit substrates 100 by heat treatment without using bumps, thereby reducing the time and man-hours required, which in turn improves productivity.

[0025] Next, the detailed configuration of the ultrasonic sensor 1000B will be described with reference to Figures 7 to 10. The ultrasonic sensor 1000B shown in Figures 7 to 10 has a configuration in which the first wiring layer 130 is arranged to extend to the second end 100b.

[0026] As shown in FIG. 7, the ultrasonic sensor 1000B includes a circuit board 100, a second board 220, a diaphragm 240, and a first board 210, which are stacked in this order in the Z direction.

[0027] The circuit board 100 is larger than the first substrate 210, the diaphragm 240, and the second substrate 220, for example.

[0028] The diaphragm 240 has a first surface 240a on the side facing the second substrate 220. A plurality of piezoelectric elements 250 are arranged in a matrix on the first surface 240a. By applying an AC voltage to the piezoelectric elements 250, the ultrasonic sensor 1000B can vibrate the diaphragm 240 and emit ultrasonic waves 500.

[0029] 10, in this embodiment, an array of 4 rows and 4 columns is configured, and therefore the number of piezoelectric elements 250 is 16. Note that the number of piezoelectric elements 250 is not particularly limited.

[0030] As shown in FIG. 7, the first substrate 210 has multiple rows of holes 214 that are long in the Y direction. In a plan view, the holes 214 have a parallelogram shape. The first substrate 210 is formed from a silicon single crystal substrate. The holes 214 are formed by wet etching. The side surfaces of the holes 214 are crystal planes with a slow etching rate. In a silicon single crystal substrate, the crystal planes with a slow etching rate are parallelograms, so the holes 214 have a parallelogram shape. The holes 214 penetrate the first substrate 210. The holes 214 are arranged in positions that face the arrangement of the piezoelectric elements 250. The number of holes 214 is not particularly limited.

[0031] The second substrate 220 is disposed between the diaphragm 240 and the circuit board 100. The second substrate 220 has a first surface 220a and a second surface 220b. The first surface 220a faces the +Z direction. The second surface 220b faces the -Z direction. The first surface 220a is bonded to the first surface 240a of the diaphragm 240.

[0032] The second substrate 220 has a plurality of rows of spaces 221 that are long in the X direction on the first surface 220a. The spaces 221 are shaped like parallelograms. The second substrate 220 is formed from a silicon single crystal substrate. The spaces 221 are formed by wet etching. Therefore, the spaces 221 have a parallelogram shape. The spaces 221 are arranged in positions that face the arrangement of the piezoelectric elements 250.

[0033] In plan view, the piezoelectric element 250 is disposed at the location where the hole 214 intersects with the space 221. Therefore, at the location where the piezoelectric element 250 is disposed, the diaphragm 240 can vibrate in the +Z direction and the −Z direction.

[0034] The diaphragm 240 and the first substrate 210 are integrated together. The material of the diaphragm 240 is silicon oxide. The diaphragm 240 is formed by oxidizing the first substrate 210.

[0035] 10, a second common wiring 230A as a third wiring and a second signal wiring 230B as a fourth wiring that constitute the second wiring layer 230 are arranged on the first surface 240a of the vibration plate 240. The second common wiring 230A and the second signal wiring 230B are electrically connected to the piezoelectric element 250.

[0036] The second substrate 220 has open holes 224 on the +X direction side of the spaces 221. The open holes 224 penetrate from the first surface 220a to the second surface 220b. The open holes 224 and the spaces 221 are connected by communication grooves 225. The four spaces 221 are connected to one another by communication grooves 226.

[0037] Second substrate 220 and diaphragm 240 are fixed by adhesive. Space 221 is not sealed because it is connected to open hole 224, communication groove 225, and communication groove 226. When diaphragm 240 vibrates, the air in space 221 is connected to the outside air, so the air pressure does not easily fluctuate. For this reason, diaphragm 240 is prone to vibrating.

[0038] The circuit board 100 has a first surface 101 facing the second surface 220b of the second board 220. A first common wiring 130A serving as a first wiring is arranged on the first surface 101 of the circuit board 100. The first common wiring 130A is electrically connected to the second common wiring 230A via a third common wiring 330A (see FIG. 2) serving as a fifth wiring.

[0039] A first signal wiring 130B serving as a second wiring is arranged on the first surface 101 of the circuit board 100. The first signal wiring 130B is electrically connected to the second signal wiring 230B via a third signal wiring 330B serving as a sixth wiring.

[0040] By supplying power to the first common wiring 130A and the first signal wiring 130B, it is possible to supply power to the piezoelectric element 250. The second substrate 220 and the circuit board 100 are flip-chip mounted.

[0041] 8 and 9, the piezoelectric element 250 is disposed at a location where the hole 214 intersects with the space 221 in a plan view. The piezoelectric element 250 is disposed on the first surface 240a of the vibration plate 240. The piezoelectric element 250 is configured by laminating a first electrode 250a, a piezoelectric layer 250b, and a second electrode 250c from the first surface 240a side.

[0042] The piezoelectric layer 250b is formed using, for example, a transition metal oxide having a perovskite structure. Specifically, the piezoelectric layer 250b is formed using lead zirconate titanate containing Pb, Ti, and Zr.

[0043] 9 and 10, the plurality of first electrodes 250a are electrically connected to second signal wiring 230B extending in the X direction. The first electrodes 250a and the second signal wiring 230B are made of the same material.

[0044] 8 and 10, the second electrodes 250c are electrically connected to a second common wiring 230A extending in the Y direction. The second electrodes 250c and the second common wiring 230A are made of the same material.

[0045] The second electrode 250c is maintained at a predetermined reference potential. When a drive pulse signal is input to the first electrode 250a, the piezoelectric element 250 is deformed and the diaphragm 240 vibrates. This causes the ultrasonic sensor 1000B to transmit ultrasonic waves 500 in the +Z direction.

[0046] When an object is present in the +Z direction of the ultrasonic sensor 1000B, the ultrasonic wave 500 is reflected by the object. When the reflected ultrasonic wave 500 passes through the hole 214 in the first substrate 210 and reaches the ultrasonic sensor 1000B, the diaphragm 240 vibrates in response to the sound pressure of the ultrasonic wave 500. The vibration of the diaphragm 240 deforms the piezoelectric layer 250b, generating a potential difference between the first electrode 250a and the second electrode 250c. As a result, a reception signal corresponding to the sound pressure of the received ultrasonic wave 500 is output from the first electrode 250a. In other words, the ultrasonic wave 500 is detected.

[0047] 10, four second signal wirings 230B extending in the X direction are arranged on the first surface 240a. The second signal wirings 230B are joined on the -X direction side. Four second common wirings 230A extending in the Y direction are arranged on the first surface 240a. The second common wirings 230A are joined on the -Y direction side.

[0048] Next, the configuration of another ultrasonic sensor 1000C will be described with reference to FIGS.

[0049] 11 and 12, the ultrasonic sensor 1000C is configured by so-called face-up mounting, in which the first substrate 210 and the diaphragm 240 are disposed so as to face the circuit board 100. The ultrasonic sensor 1000C is disposed so that the second wiring layer 230 formed on the diaphragm 240 is exposed on the upper side, i.e., the +Z direction side.

[0050] 1 to 10 are configured by so-called face-down mounting, in which the second substrate 220 is disposed so as to face the circuit substrate 100. The ultrasonic sensors 1000, 1000A, 1000B are disposed so that the second wiring layer 230 formed on the diaphragm 240 is exposed on the lower side, i.e., on the −Z direction side.

[0051] As shown in FIGS. 11 and 12, another ultrasonic sensor 1000C includes a circuit board 100 and an element board 200 mounted on the circuit board 100.

[0052] The circuit board 100 has a circuit section 110, a holding member 120, a mounting section 300, and a first wiring layer 130. The circuit board 100 is provided with a second opening 150 at a position facing the first substrate 210. The second opening 150 is provided to open the emission direction of the ultrasonic waves 500 and to prevent a decrease in the intensity of the ultrasonic waves 500.

[0053] In this way, the ultrasonic sensor 1000C emits the ultrasonic waves 500 downward, that is, in the -Z direction. As shown in Fig. 2, the ultrasonic sensor 1000 emits the ultrasonic waves 500 upward, that is, in the +Z direction.

[0054] The element substrate 200 has, from the circuit board 100 side, a first substrate 210, a vibration plate 240, a piezoelectric element 250, a second substrate 220, and a second wiring layer 230.

[0055] The second wiring layer 230 is electrically connected to the piezoelectric elements 250. The second wiring layer 230 is arranged to extend to the outside of the second substrate 220. The first wiring layer 130 arranged on the circuit substrate 100 and the second wiring layer 230 arranged on the element substrate 200 are electrically connected by a third wiring layer 330.

[0056] The third wiring layer 330 is covered with the protective member 310. In this manner, the second wiring layer 230 and the first wiring layer 130 are arranged facing upward, i.e., facing the +Z direction, so that it is easy to apply the conductive material 330a (see FIG. 13E) that becomes the third wiring layer 330.

[0057] As described above, in face-up mounting in which the first substrate 210 and the circuit substrate 100 are disposed opposite each other, that is, the second substrate 220 is disposed at a position farther away from the circuit substrate 100 than the first substrate 210, the first wiring layer 130 and the second wiring layer 230 can be electrically connected by the third wiring layer 330. Therefore, the plurality of element substrates 200 and the plurality of circuit substrates 100 can be hardened collectively by heat treatment.

[0058] Next, a method for manufacturing the ultrasonic sensor 1000C will be described with reference to Figures 13A to 13G. Note that the ultrasonic sensor 1000C will be described using the above-mentioned face-up mounting as an example.

[0059] 13A, a first wiring layer 130 and a holding member 120 are formed on the circuit board 100. Examples of materials for the first wiring layer 130 include silver (Ag) paste. The material for the holding member 120 is preferably a material with a high viscosity that can withstand the weight of the element substrate 200 when the element substrate 200 is placed on it. Furthermore, by forming the holding member 120 thin, tilting of the element substrate 200 can be suppressed. Examples of materials for the holding member 120 include adhesive, double-sided tape, and silver paste.

[0060] 13B, the position of the IC chip, i.e., the second substrate 220, is aligned with respect to the circuit substrate 100. Specifically, the second wiring layer 230, the first substrate 210, and the diaphragm 240 are formed on the second substrate 220 in advance. Next, the second substrate 220 is attracted to the tool heater 600. In this state, the position of the second substrate 220 with respect to the circuit substrate 100 is aligned with respect to the tool heater 600. Note that the tool heater 600 is not heated at this time.

[0061] 13C, the element substrate 200 is mounted on the holding member 120. Specifically, the element substrate 200 including the second substrate 220 is placed on the holding member 120 formed on the circuit substrate 100. This temporarily determines the position of the element substrate 200 relative to the circuit substrate 100. In other words, the circuit substrate 100 and the element substrate 200 are temporarily fixed together.

[0062] 13D, the circuit board 100 and the element substrate 200 are fixed together using an oven. Specifically, the holding member 120 is hardened by heating using heat 610 of the oven.

[0063] 13E, the first wiring layer 130 and the second wiring layer 230 are electrically connected using a conductive material 330a. Specifically, the conductive material 330a made of silver paste or the like is applied so as to cover the second wiring layer 230 to the first wiring layer 130. The application method can be, for example, a dispenser.

[0064] 13F, the conductive material 330a is cured using an oven. Specifically, the conductive material 330a is cured by heating using the heat 610 of the oven. As a result, the conductive material 330a is cured and becomes the third wiring layer 330, and the first wiring layer 130 and the second wiring layer 230 are electrically connected.

[0065] In this way, after the circuit board 100 and the element substrate 200 are fixed together, the conductive material 330a electrically connecting the first wiring layer 130 and the second wiring layer 230 is hardened by heat treatment. This prevents the element substrate 200 from tilting without being affected by the contraction of the conductive material 330a during heat treatment. Therefore, unlike the conventional method, heat treatment does not need to be performed for each element substrate 200, and multiple chips, i.e., multiple element substrates 200, can be heat treated at once. This reduces the cycle time during manufacturing. The multiple chips may be, for example, about 200 chips.

[0066] Next, in the step shown in FIG. 13G, the protective member 310 is formed. Specifically, the protective member 310 is formed so as to cover the first wiring layer 130, the second wiring layer 230, and the third wiring layer 330. As described above, examples of the material for the protective member 310 include urethane resin, epoxy resin, and acrylic resin. This prevents the first wiring layer 130, the second wiring layer 230, and the third wiring layer 330 from being exposed to the outside. Specifically, it prevents moisture from penetrating the wiring layers 130, 230, 330, etc.

[0067] Next, the second opening 150 is formed in a portion of the circuit board 100 that is in the direction in which the ultrasonic sensor 1000C emits the ultrasonic wave 500. The second opening 150 may be formed in advance at the same time as the circuit board 100 is formed.

[0068] As described above, compared to the conventional method of electrically connecting the first wiring layer 130 and the second wiring layer 230 using bumps, the element substrate 200 is fixed to the circuit substrate 100 first, and then the first wiring layer 130 and the second wiring layer 230 are connected by the third wiring layer 330. This eliminates the need to perform heat treatment on a per-IC chip basis, i.e., per-element substrate 200 basis, and allows multiple circuit substrates 100 and multiple element substrates 200 to be heat treated collectively. Therefore, the ultrasonic sensor 1000C can be formed quickly while reducing the number of steps required.

[0069] Furthermore, the ultrasonic sensors are not limited to the ultrasonic sensors 1000, 1000A, 1000B, and 1000C described above, and may be an ultrasonic sensor 1000D formed by bonding wire mounting, as shown in FIGS.

[0070] 14 and 15, the ultrasonic sensor 1000D electrically connects the first wiring layer 130 and the second wiring layer 230 with a third wiring layer 330D made of a bonding wire. Note that the formation of the third wiring layer 330D is not limited to the ultrasonic sensors 1000, 1000A, 1000B, and 1000C that use silver paste or the like, and the connection may be made with a bonding wire, and it is preferable to select and apply an appropriate method.

[0071] Furthermore, ultrasonic sensors 1000, 1000A, 1000B, 1000C, and 1000D may be used and applied to double feed detection device 2000. The principle of double feed detection device 2000 is shown in Figures 16A and 16B.

[0072] 16A shows a state in which one document 1002 is sandwiched between, for example, an ultrasonic sensor 1000 functioning as a transmitting element and a receiving unit 1001 functioning as a receiving element. FIG. 16B shows a state in which two documents 1002 (i.e., a double feed) are sandwiched between the ultrasonic sensor 1000 and the receiving unit 1001. The receiving unit 1001 receives ultrasonic waves 500 transmitted from the ultrasonic sensor 1000 and transmitted through the document 1002.

[0073] 16A, when there is one sheet of document 1002, document 1002 vibrates due to the transmitted ultrasonic waves 500, and ultrasonic waves are transmitted again from document 1002 and received by receiving unit 1001. This makes it possible to determine that there is one sheet of document 1002.

[0074] 16B, when there are two originals 1002, there is an air gap between the first and second sheets, so that the ultrasonic waves 500 emitted from the first sheet are blocked by the air gap, and almost no ultrasonic waves are output from the second sheet. This allows us to determine that there are two originals 1002.

[0075] In this way, it is determined whether the document 1002 is one sheet or two sheets depending on the intensity of the ultrasonic wave 500 received by the receiving unit 1001. The double feed detection device 2000 can be used to detect double feed in a printer, scanner, or the like.

[0076] As described above, the ultrasonic sensor 1000 of this embodiment is an ultrasonic sensor 1000 in which the element substrate 200 is mounted on the circuit board 100, and the circuit board 100 includes the circuit section 110, the mounting section 300 in which the holding member 120 that holds the element substrate 200 is arranged and in which the element substrate 200 is mounted, and the first wiring layer 130 that is electrically connected to the circuit section 110 and has one end extending to at least a part of the area surrounding the mounting section 300, and the element substrate 200 has a first surface 210a and a second surface 210b opposite to the first surface 210a, and a first opening 21 extending from the first surface 210a to the second surface 210b. 1 is formed, a vibration plate 240 that closes the first surface 210a side of the first opening 211, a piezoelectric element 250 provided on the surface of the vibration plate 240 opposite the first opening 211, a second substrate 220 that is arranged opposite the surface of the vibration plate 240 opposite the first opening 211 and has a space 221 formed therein to accommodate the piezoelectric element 250, a second wiring layer 230 that is electrically connected to the piezoelectric element 250 and extends to the outside of the second substrate 220, a third wiring layer 330 that electrically connects the first wiring layer 130 and the second wiring layer 230, and a protective member 310 that covers the third wiring layer 330.

[0077] According to this configuration, the first wiring layer 130 electrically connected to the circuit section 110, the second wiring layer 230 electrically connected to the piezoelectric elements 250, and the third wiring layer 330 electrically connecting the first wiring layer 130 and the second wiring layer 230 are provided, so that, compared to the conventional method of using bumps to harden one element substrate 200 to one circuit substrate 100 by heat treatment, it is possible to simultaneously harden a plurality of element substrates 200 and a plurality of circuit substrates 100 by heat treatment, thereby reducing the time and man-hours required, which in turn improves productivity.

[0078] Furthermore, in the ultrasonic sensor 1000 of this embodiment, the second substrate 220 is preferably disposed opposite the circuit board 100 in the mounting section 300. With this configuration, the second substrate 220 and the circuit board 100 are disposed opposite each other, that is, in face-down mounting in which the first substrate 210 is disposed farther away from the circuit board 100 than the second substrate 220, the first wiring layer 130 and the second wiring layer 230 can be electrically connected by the third wiring layer 330. Therefore, the plurality of element substrates 200 and the plurality of circuit boards 100 can be hardened collectively by heat treatment.

[0079] Furthermore, in the ultrasonic sensor 1000C of this embodiment, it is preferable that the first substrate 210 is disposed opposite the circuit board 100 in the mounting section 300. With this configuration, the first substrate 210 and the circuit board 100 are disposed opposite each other, that is, in face-up mounting in which the second substrate 220 is disposed farther away from the circuit board 100 than the first substrate 210, the first wiring layer 130 and the second wiring layer 230 can be electrically connected by the third wiring layer 330. Therefore, the plurality of element substrates 200 and the plurality of circuit boards 100 can be hardened collectively by heat treatment.

[0080] Furthermore, in the ultrasonic sensor 1000C of this embodiment, it is preferable that the second opening 150 is provided at a position on the circuit board 100 that faces the first substrate 210. According to this configuration, in face-up mounting, the second opening 150 is provided at a position that faces the first substrate 210. Therefore, for example, in the ultrasonic sensor 1000C, there is nothing that obstructs the direction in which the ultrasonic waves 500 are emitted, and it is possible to prevent the intensity of the ultrasonic waves 500 from being weakened.

[0081] In the ultrasonic sensor 1000 of this embodiment, the piezoelectric element 250 is preferably configured by laminating a first electrode 250a, a piezoelectric layer 250b, and a second electrode 250c. With this configuration, for example, the first electrode 250a and the second electrode 250c are laminated with the piezoelectric layer 250b sandwiched therebetween, so that the diaphragm 240 can be vibrated by inputting a signal to the first electrode 250a or the second electrode 250c.

[0082] Furthermore, in the ultrasonic sensor 1000 of this embodiment, the first wiring layer 130 has a first common wiring 130A and a first signal wiring 130B that are insulated from each other, the second wiring layer 230 has a second common wiring 230A and a second signal wiring 230B that are insulated from each other, and the third wiring layer 330 has a third common wiring 330A and a third signal wiring 330B (see FIG. 2) that are insulated from each other, and it is preferable that the first common wiring 130A and the second common wiring 230A are electrically connected by the third common wiring 330A, and the first signal wiring 130B and the second signal wiring 230B are electrically connected by the third signal wiring 330B. This configuration makes it possible to provide an ultrasonic sensor 1000 that is configured with the connections described above.

[0083] Furthermore, the double feed detection device 2000 of this embodiment includes the above-described ultrasonic sensor 1000. According to this configuration, it is possible to provide the double feed detection device 2000 that can improve productivity.

[0084] A modification of the above embodiment will now be described.

[0085] As described above, the ultrasonic sensor 1000 has been used as an example of the mounting body, but the present invention is not limited to this and may be applied to other sensors, piezoelectric devices, etc. Examples of sensors include photoelectric sensors, laser sensors, proximity sensors, and displacement sensors.

[0086] As described above, the protective member 310 is not limited to being disposed so as to cover the third wiring layer 330, and the protective member 310 does not necessarily have to be disposed.

[0087] As described above, the element substrate 200 is fixed to the circuit board 100 using the holding member 120, but this is not limitative, and the holding member 120 may not be used. [Explanation of symbols]

[0088] 100...circuit board, 100a...first end, 100b...second end, 100c...third end, 100d...fourth end, 101...first surface, 110...circuit section, 120...holding member, 130...first wiring layer, 130A...first common wiring as first wiring, 130B...first signal wiring as second wiring, 150...second opening, 200...element substrate, 210...first substrate, 210a...first surface, 210b...second surface, 211...first opening, 214...hole, 220...second substrate, 220a...first surface, 220b...second surface, 221...space, 224...open hole, 225...communicating groove, 226...communicating groove, 230...second wiring layer, 230A...third wiring Second common wiring, 230B...second signal wiring as fourth wiring, 240...diaphragm, 240a...first surface, 250...piezoelectric element, 250a...first electrode, 250b...piezoelectric layer, 250c...second electrode, 300...mounting portion, 310...protective member, 330...third wiring layer, 330a...conductive material, 330D...third wiring layer, 330A...third common wiring as fifth wiring, 330B...third signal wiring as sixth wiring, 500...ultrasonic, 600...tool heater, 610...heat, 1000, 1000A, 1000B, 1000C, 1000D...ultrasonic sensor, 1001...receiving unit, 1002...original, 2000...double feed detection device.

Claims

1. A mounting assembly in which an element substrate is mounted on a circuit board, The circuit board includes: A circuit unit; a mounting section in which a holding member for holding the element substrate is disposed and the element substrate is mounted; a first wiring layer electrically connected to the circuit section and having one end extending to at least a part of an area surrounding the mounting section; Equipped with The element substrate is a first substrate having a first surface and a second surface opposite to the first surface, and a first opening formed from the first surface to the second surface; a diaphragm that closes the first surface side of the first opening; a piezoelectric element provided on a surface of the vibration plate opposite to the first opening; a second substrate disposed opposite to a surface of the vibration plate opposite to the first opening, the second substrate having a space formed therein for accommodating the piezoelectric element; a second wiring layer electrically connected to the piezoelectric element and extending to the outside of the second substrate; a third wiring layer electrically connecting the first wiring layer and the second wiring layer; a protective member covering the third wiring layer; An implementation body comprising:

2. 2. The mounting assembly according to claim 1, In the mounting portion, the second substrate is disposed opposite the circuit board.

3. 2. The mounting assembly according to claim 1, In the mounting portion, the first substrate is disposed opposite the circuit board.

4. The mounting assembly according to claim 3, a second opening provided in the circuit board at a position facing the first board;

5. 2. The mounting assembly according to claim 1, The piezoelectric element is a mounting body configured by laminating a first electrode, a piezoelectric layer, and a second electrode.

6. 6. The mounting assembly according to claim 5, the first wiring layer has first wiring and second wiring that are insulated from each other; the second wiring layer has third wiring and fourth wiring insulated from each other; the third wiring layer has fifth wiring and sixth wiring that are insulated from each other; the first wiring and the third wiring are electrically connected by the fifth wiring, The second wiring and the fourth wiring are electrically connected by the sixth wiring.

7. An ultrasonic sensor comprising the mounting assembly according to claim 1 .

8. A double feed detection device comprising the ultrasonic sensor according to claim 7.

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