WO2022137828A1

WO2022137828A1 - Strain sensor

Info

Publication number: WO2022137828A1
Application number: PCT/JP2021/040717
Authority: WO
Inventors: 英治梅津
Original assignee: アルプスアルパイン株式会社
Priority date: 2020-12-21
Filing date: 2021-11-05
Publication date: 2022-06-30
Also published as: JP2024012731A

Abstract

This strain sensor makes it easy to detect strain in an object. One embodiment of this strain sensor detects strain in a strain body and comprises: a package substrate; a base substrate that is disposed on the package substrate and comprises an electrical wiring unit; a sensor substrate that is disposed on the base substrate and comprises a plurality of piezoresistance elements; and a mold resin that covers the base substrate and sensor substrate on the package substrate. The surface of the sensor substrate protrudes further than the surface of the mold resin, and the surfaces of the mold resin and sensor substrate are the surfaces that are attached to the strain body.

Description

Distortion sensor

The present invention relates to a strain sensor, and more particularly to a strain sensor that detects strain when a force is applied to an object.

As a strain sensor, Patent Document 1 discloses a mechanical quantity measuring device that measures strain in a specific direction with a small error. In this dynamic quantity measuring device, in the silicon substrate of the semiconductor dynamic quantity measuring apparatus, for example, the ratio of the substrate thickness to the substrate length in the measuring direction is small, and the ratio of the substrate thickness to the substrate length in the direction perpendicular to the measuring direction is small. Is getting bigger.

Further, Patent Document 2 discloses a mechanical quantity measuring device that is not easily affected by noise even when circuit operating power is supplied by electromagnetic induction or microwave, and enables highly accurate measurement. In this mechanical quantity measuring device, the strain is measured by adhering the bonded portion to the object to be measured.

Japanese Unexamined Patent Publication No. 2006-003182 Japanese Unexamined Patent Publication No. 2005-114443

In order to detect minute strains of an object with high accuracy, it is necessary to effectively transmit the strain of the strain-causing body to the strain sensor. As the object becomes smaller, the area for mounting the strain sensor is limited, so that it becomes difficult to effectively transmit the strain.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a distortion sensor having a configuration that makes it easy to detect distortion of an object.

One aspect of the present invention is a strain sensor for detecting the strain of a strain-causing body, which is arranged on a package substrate, a base substrate having an electrical wiring portion, and a base substrate. A sensor substrate having a plurality of piezo resistance elements, a base substrate on a package substrate, and a mold resin covering the sensor substrate are provided, and the surface of the sensor substrate protrudes from the surface of the molding resin, and the surface of the mold resin and the sensor substrate. It is a strain sensor characterized in that the surface serves as a mounting surface for a strain-causing body.

In this way, the surface of the sensor substrate protrudes from the surface of the mold resin, and the surface of the mold resin and the surface of the sensor substrate serve as the mounting surface for the strain-causing body, so that the surface of the sensor substrate is firmly fixed to the strain-causing body around the sensor substrate. At the same time, it makes it easier to detect the distortion from the strain-causing body.

In the strain sensor, the sensor substrate may be provided separately from the mold resin. In this way, by providing the protruding sensor board and the sealing mold resin separately, the portion covered with the mold resin is fixed, and the sensor board makes it easier to detect distortion. ..

In the strain sensor, the Young's modulus of the sensor substrate is preferably higher than the Young's modulus of the molded resin. Since the Young's modulus of the sensor substrate is higher than the Young's modulus of the mold resin, the mold resin is softer, so that when it is distorted, it moves together with the strain-causing body and becomes easily distorted.

In the strain sensor, the longitudinal direction of the sensor substrate is preferably substantially parallel to the strain direction of the strain-causing body. In this way, the longitudinal direction of the sensor substrate is parallel to the strain direction of the strain-causing body, which makes it easier to detect the strain.

In the strain sensor, it is preferable that an adhesive layer is provided between the surface of the mold resin and the strain-causing body. This allows the adhesive layer to fix the strain sensor on the surface of the mold resin when it is attached to the strain generator.

In the strain sensor, an adhesive layer is provided between the surface of the mold resin and the strain-causing body, and between the surface of the sensor substrate and the strain-causing body, and the adhesive layer from the surface of the sensor substrate to the strain-causing body is provided. The thickness of the adhesive layer is preferably thinner than the thickness of the adhesive layer from the surface of the mold resin to the strain-causing body. As a result, when the strain sensor is attached to the strain-causing body by the adhesive layer, it can be securely fixed between the surface of the mold resin and the surface of the sensor substrate, and the attenuation due to the adhesive layer when the strain is transmitted to the sensor substrate is suppressed. , It becomes easier to detect distortion.

In the distortion sensor, a circuit board having a signal processing circuit for processing a signal output from the sensor board may be provided between the package board and the base board. In this way, the circuit board can also be protected by being sealed with the mold resin, and can be housed in one package including the circuit board, so that the installation space can be reduced.

According to the present invention, it is possible to provide a distortion sensor having a configuration that makes it easy to detect distortion of an object.

It is a perspective view which illustrates the structure of the strain sensor which concerns on this embodiment. It is sectional drawing which illustrates the structure of the strain sensor which concerns on this embodiment. It is an exploded perspective view which illustrates the sensor board. It is sectional drawing which illustrates the state of attachment to the strain-causing body of a strain sensor. It is a schematic cross-sectional view which illustrates the positional relationship between a displacement part and a piezo resistance element. (A) and (b) are schematic diagrams illustrating the layout of the piezo resistance element. (A) and (b) are schematic diagrams illustrating the layout of the piezo resistance element. (A) and (b) are schematic diagrams illustrating the layout of the piezo resistance element. It is a figure which shows the relationship between the exposure height of a sensor substrate in a strain sensor, and the amount of sensor strain. (A) to (e) are schematic views illustrating an exposed state of a sensor substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same members are designated by the same reference numerals, and the description of the members once described will be omitted as appropriate.

(Distortion sensor configuration)
FIG. 1 is a perspective view illustrating the configuration of the strain sensor according to the present embodiment.
FIG. 2 is a cross-sectional view illustrating the configuration of the strain sensor according to the present embodiment.
FIG. 3 is an exploded perspective view illustrating the sensor substrate.
Note that FIG. 1 shows a state in which the mold resin 40 is seen through. Further, in FIG. 2, the cross section taken along the line AA shown in FIG. 1 is shown. Further, FIG. 3A shows an exploded perspective view of the sensor substrate 30 from the front surface side, and FIG. 3B shows an exploded perspective view of the sensor substrate 30 from the back surface side.

This embodiment is a strain sensor 1 for detecting the strain of a strain-causing body, and includes a package substrate 10, a base substrate 20, a sensor substrate 30, and a mold resin 40. In the description of the embodiment, the normal direction of the board mounting surface 10a of the package substrate 10 is the Z direction, one of the directions orthogonal to the normal direction (Z direction) is the X direction, and the other one is the Y direction. do.

The package substrate 10 is a portion that constitutes the appearance of the strain sensor 1 together with the mold resin 40, and is a substrate provided on the bottom surface side of the strain sensor 1. The size of the package substrate 10 in the plan view in the Z direction is about 2 mm (mm) in length × about 2 mm in width.

The package substrate 10 has a substrate mounting surface 10a on which the base substrate 20 is mounted, and a pad surface 10b provided on the side opposite to the substrate mounting surface 10a. The pad portion 16 is provided on the extension surface of the substrate mounting surface 10a of the package substrate 10. A plurality of electrode terminals 11 are provided on the pad surface 10b of the package substrate 10 in order to obtain continuity with the outside. The electrode terminals 11 connect to and conduct with the outside (for example, the flexible substrate F (see FIG. 4 described later)).

The base substrate 20 is arranged on the package substrate 10 (stacked in the Z direction). The base board 20 has a sensor mounting surface 20a on which the sensor board 30 is mounted. Further, the base substrate 20 has an electrical wiring unit 25 that is electrically connected to each of the plurality of piezo resistance elements 35 provided on the sensor substrate 30.

The sensor board 30 is arranged on the base board 20 (stacked in the Z direction). The sensor substrate 30 has a displacement portion 31 and a piezo resistance element 35. The sensor substrate 30 has a substantially rectangular shape in a plan view in the Z direction, and a displacement portion 31 is provided at a central portion thereof. The displacement portion 31 is a portion that is displaced by receiving the strain of the strain-causing body 100, and is provided on the surface of the sensor substrate 30 on the base substrate 20 side. The piezo resistance element 35 is an element that electrically detects the amount of displacement of the displacement portion 31.

A circuit board 50 may be provided between the package board 10 and the base board 20. The circuit board 50 has a signal processing circuit (signal processing IC) that processes the signal output from the sensor board 30. When the circuit board 50 is provided, the base board 20 and the circuit board 50 are conducted by the first bonding wire 61, and the circuit board 50 and the package board 10 are conducted by the second bonding wire 62.

The mold resin 40 is a sealing resin that covers the base substrate 20 and the sensor substrate 30 on the package substrate 10. The mold resin 40 may be composed of only the resin, or may have a filler component made of an inorganic material or the like. The mold resin 40 is a part that constitutes the appearance of the strain sensor 1 together with the package substrate 10. When the circuit board 50 is provided, the circuit board 50 is covered with the mold resin 40 together with the base board 20 and the sensor board 30.

In the strain sensor 1 according to the present embodiment having such a configuration, the surface 30a of the sensor substrate 30 protrudes from the surface 40a of the mold resin 40, and the surface 40a of the mold resin 40 and the surface 30a of the sensor substrate 30 cause strain. It is a mounting surface with the body 100 (see FIG. 4 described later). In this way, the surface 30a of the sensor substrate 30 protrudes from the surface 40a of the mold resin 40, and the surface 40a of the mold resin 40 and the surface 30a of the sensor substrate 30 serve as mounting surfaces for the strain-causing body 100. While firmly fixing to the strain-causing body 100 around 30, it is easy to detect the strain from the strain-causing body 100.

Further, in the strain sensor 1 according to the present embodiment, it is preferable that the sensor substrate 30 is provided separately from the mold resin 40. As a result, the deformation of the sensor substrate 30 and the deformation of the mold resin 40 are less likely to interfere with each other, so that the sensor substrate 30 can easily detect distortion even if the portion covered with the mold resin 40 is fixed.

Further, it is preferable that the Young's modulus of the sensor substrate 30 is higher than the Young's modulus of the mold resin 40. Since the Young's modulus of the sensor substrate 30 is higher than the Young's modulus of the mold resin 40, the mold resin 40 becomes softer, and when the strain-causing body 100 is distorted, the mold resin 40 moves together. It becomes easy to be distorted, and it becomes easy to detect the distortion by the sensor board 30. Further, when the sensor substrate 30 is deformed according to the strain of the strain-causing body 100, the mold resin 40 is less likely to become a deformation resistance. Here, when the sensor substrate 30 is made of a semiconductor such as silicon, the Young's modulus thereof is 100 GPa or more. Therefore, the Young's modulus of the mold resin 40 is preferably 20 GPa or less, preferably 10 GPa or less. It is more preferable to have. In other words, the Young's modulus of the mold resin 40 is preferably 20% or less, and more preferably 10% or less, with respect to the Young's modulus of the sensor substrate 30.

(Attachment state of strain sensor to strain generator)
FIG. 4 is a cross-sectional view illustrating a state in which the strain sensor is attached to the strain-causing body.
The strain sensor 1 according to the present embodiment is attached to the surface of the strain generating body 100 by, for example, an adhesive layer 80. The adhesive layer 80 is made of, for example, a resin-based material, and is provided between the surface 40a of the mold resin 40 and the strain-causing body 100. Since the area of the surface 40a of the mold resin 40 is larger than the area of the surface 30a of the sensor substrate 30, the strain sensor 1 is caused by being adhered to the strain generating body 100 by the adhesive layer 80 on the surface 40a. It will be possible to firmly fix it to 100.

In the strain sensor 1 according to the present embodiment, it is preferable that the longitudinal direction (for example, the X direction) of the sensor substrate 30 is substantially parallel to the strain direction SD of the strain generating body 100. As a result, the sensor substrate 30 is more likely to be distorted by the strain-causing body 100, and the strain sensor 1 is more likely to detect the strain.

Further, the adhesive layer 80 may be provided between the surface 30a of the sensor substrate 30 protruding from the surface 40a of the mold resin 40 and the strain-causing body 100. The portion of the adhesive layer 80 between the surface 30a of the sensor substrate 30 and the strain-causing body 100 is defined as the first portion 80a, and the portion between the surface 40a of the mold resin 40 and the strain-causing body 100 is defined as the second portion 80b. The thickness t1 of the first portion 80a (thickness t1 of the adhesive layer 80 from the surface 30a of the sensor substrate 30 to the strain generating body 100) is raised from the thickness t2 of the second portion 80b (the surface 40a of the mold resin 40). It is thinner than the thickness t2) of the adhesive layer 80 up to the strained body 100.

Thereby, when the strain sensor 1 is attached to the strain generating body 100 by the adhesive layer 80, the functions of the adhesive layer 80 can be separated. That is, since the second portion 80b of the adhesive layer 80 located between the surface 40a of the mold resin 40 and the surface of the strain generating body 100 is relatively thick, the strain sensor 1 is surely used with respect to the strain generating body 100. Can be fixed. When the strain-causing body 100 is distorted, the relatively thick second portion 80b can absorb the strain and suppress peeling between the second portion 80b and the mold resin 40. Further, since the mold resin 40 has a Young's modulus lower than that of the sensor substrate 30, even if the strain from the strain-causing body 100 is transmitted to the mold resin 40, the mold resin 40 can absorb the strain.

On the other hand, since the first portion 80a of the adhesive layer 80 located between the surface 30a of the sensor substrate 30 and the surface of the strain generating body 100 is relatively thin, when the strain of the strain generating body 100 is transmitted to the sensor substrate 30. In addition, it is difficult to attenuate in the first portion 80a, and distortion is easily detected by the piezo resistance element 35 of the sensor substrate 30. Further, since the Young's modulus of the mold resin 40 located around the sensor substrate 30 is lower than that of the sensor substrate 30, the mold resin 40 is deformed against the deformation of the sensor substrate 30 according to the strain of the strain-causing body 100. It is difficult to become. In this way, by making the thickness of the first portion 80a and the thickness of the second portion 80b of the adhesive layer 80 different from each other, even if the strain sensor 1 is miniaturized and its attachment area to the strain generating body 100 is reduced. It is realized that the strain sensor 1 does not easily fall off when the strain-causing body 100 is distorted, and that the strain of the strain-causing body 100 is appropriately detected on the sensor substrate 30.

The hardness of the adhesive layer 80 may be changed between the first portion 80a and the second portion 80b. In this case, it is preferable that the hardness of the adhesive layer 80 of the first portion 80a is harder than the hardness of the adhesive layer 80 of the second portion 80b. This makes it easier for the sensor substrate 30 to detect the strain of the strain-causing body 100 via the hard adhesive layer 80. The hardness of the adhesive layer 80 can be appropriately adjusted by changing its component, for example, by including a hard filler component in addition to the resin component.

On the other hand, from the viewpoint of manufacturing, it is preferable to use the same adhesive layer 80 for the first portion 80a and the second portion 80b. In this case, the hardness of the adhesive layer 80 is the same in the first portion 80a and the second portion 80b. In the present embodiment, since the thickness t1 of the adhesive layer 80 of the first portion 80a is thinner than the thickness t2 of the adhesive layer 80 of the second portion 80b, the thickness t1 of the first portion 80a and the second portion 80b Even if the hardness of the adhesive layer 80 of both portions is the same, the cushioning action of the adhesive layer 80 is weak until the strain from the strain-causing body 100 is transmitted to the sensor substrate 30, and the strain is easily detected. ..

In particular, since the strain sensor 1 according to the present embodiment is a minute size (package substrate 10 size) of about 2 mm in each of the vertical and horizontal directions, the strain sensor 1 is attached to the strain generator 100 by a fastening member such as a bolt. It is difficult to fix, and adhesive fixing by the adhesive layer 80 is advantageous. A sufficient adhesive area is required for fixing the strain sensor 1 to the strain-causing body 100 by the adhesive layer 80. In the strain sensor 1 according to the present embodiment, even when the strain sensor 1 is fixed to the strain generator 100 by one kind of adhesive layer 80 which is advantageous in manufacturing, the strain sensor 1 is securely fixed to the strain generator 100. And high-sensitivity strain detection by the strain sensor 1 can be achieved at the same time.

(Layout example of piezo resistance element)
Next, a layout example of the piezo resistance element 35 applied to the strain sensor 1 according to the present embodiment will be described.
FIG. 5 is a schematic cross-sectional view illustrating the positional relationship between the displacement portion and the piezo resistance element.
A seal 26 is provided between the base substrate 20 and the sensor substrate 30. The seal 26 is made of a metal such as gold or silver, and serves to support the sensor substrate 30 on the base substrate 20 and to make an electrical connection. A displacement portion 31 is provided in a region inside the seal 26 on the surface of the sensor substrate 30 on the side of the base substrate 20. In the strain sensor 1, a plurality of piezo resistance elements 35 are arranged inside the displacement portion 31.

6 to 8 are schematic views illustrating the layout of the piezo resistance element.
6 to 8, each (a) shows the layout of the piezo resistance element 35 in a plan view, and (b) shows the circuit diagram of the piezo resistance element 35.

The sensor substrate 30 has a substantially rectangular shape in a plan view, and the displacement portion 31 is arranged in the central portion. The arrow shown indicates the distortion direction SD. When the sensor substrate 30 is substantially rectangular, distortion can be easily detected by making the longitudinal direction (for example, the X direction) substantially parallel to the distortion direction SD.

6 (a) and 6 (b) show an example of forming a full bridge with a plurality of piezo resistance elements 35. Further, FIGS. 7 (a) and 7 (b), and FIGS. 8 (a) and 8 (b) show an example in which a half bridge is formed by a plurality of piezo resistance elements 35.

In each example, the piezo resistance element 35 constitutes four element groups 35G (first element group 35G1, second element group 35G2, third element group 35G3, and fourth element group 35G4). Three piezo resistance elements 35 are provided in one element group 35G, each of which is arranged in parallel in the same direction and electrically connected in series. For example, in FIG. 6, the first element group 35G1 is formed by connecting three piezo resistance elements 35 extending in the Y direction in series. The relative arrangement of the four element groups 35G on the sensor substrate 30 is as follows. That is, the first element group 35G1 is arranged in the upper left, the second element group 35G2 is arranged in the upper right, the third element group 35G3 is arranged in the lower left, and the fourth element group 35G4 is arranged in the lower right.

In the example shown in FIG. 6A, the piezo resistance elements 35 of the first element group 35G1 and the fourth element group 35G4 are arranged in a direction orthogonal to the strain direction SD, and the second element group 35G2 and the third element group 35G3 The piezo resistance element 35 is arranged in the distortion direction SD.

As shown in FIG. 6B, in order to form a full bridge, the first element group 35G1 and the third element group 35G3 are electrically connected in series, and the second element group 35G2 and the fourth element group 35G4 are connected in series. Conducts. The first element group 35G1 and the third element group 35G3 and the second element group 35G2 and the fourth element group 35G4 conduct in parallel. The power supply voltage VDD between the first element group 35G1 and the second element group 35G2, and the ground potential GND between the third element group 35G3 and the fourth element group 35G4. Further, the output potential V1 is between the first element group 35G1 and the third element group 35G3, and the output potential V2 is between the second element group 35G2 and the fourth element group 35G4.

In the example shown in FIG. 7A, the piezo resistance element 35 of the first element group 35G1 is arranged in a direction orthogonal to the strain direction SD, and the second element group 35G2, the third element group 35G3, and the fourth element group 35G4 The piezo resistance element 35 is arranged in the distortion direction SD.

As shown in FIG. 7B, in order to form a half bridge, the first element group 35G1 and the second element group 35G2 are electrically connected in series, and the third element group 35G3 and the fourth element group 35G4 are connected in series. Conducts. Of the series connections of the first element group 35G1 and the second element group 35G2, the second element group 35G2 side has the power supply voltage VDD, and the first element group 35G1 has the output potential V1. Further, of the series connection between the third element group 35G3 and the fourth element group 35G4, the fourth element group 35G4 side has the ground potential GND. In this half-bridge configuration, the first element group 35G1 and the second element group 35G2 are reference resistances, and the third element group 35G3 and the fourth element group 35G4 are sensor resistances.

In the example shown in FIG. 8A, the piezo resistance elements 35 of the first element group 35G1 and the second element group 35G2 are arranged in a direction orthogonal to the strain direction SD, and the third element group 35G3 and the fourth element group 35G4 are arranged. The piezo resistance element 35 is arranged in the distortion direction SD.

As shown in FIG. 8B, in order to form a half bridge, the first element group 35G1 and the second element group 35G2 are electrically connected in series, and the third element group 35G3 and the fourth element group 35G4 are connected in series. Conducts. Of the series connections of the first element group 35G1 and the second element group 35G2, the second element group 35G2 side has the power supply voltage VDD, and the first element group 35G1 has the output potential V1. Further, of the series connection between the third element group 35G3 and the fourth element group 35G4, the fourth element group 35G4 side has the ground potential GND. In this half-bridge configuration, the resistance values of the first element group 35G1 and the second element group 35G2 decrease with respect to the strain, and the resistance values of the third element group 35G3 and the fourth element group 35G4 increase. Therefore, in the half-bridge configuration shown in FIG. 8, the output value is larger than that in the half-bridge configuration shown in FIG. 7.

(Characteristics of distortion sensor)
Next, the characteristics of the strain sensor according to this embodiment will be described.
FIG. 9 is a diagram showing the relationship between the exposure height of the sensor substrate in the strain sensor and the amount of sensor strain.
In FIG. 9, the horizontal axis shows the exposure height (micrometer: μm) of the surface 30a of the sensor substrate 30 from the surface 40a of the mold resin 40, and the vertical axis shows the strain amount (microstrain: μst). The strain amount on the vertical axis is a simulation result of the strain amount of the sensor substrate 30 when 14.3 kilonewtons (kN) are added to the strain generator 100 in the X direction.
10 (a) to 10 (e) are schematic views illustrating an exposed state of the sensor substrate.
The exposed state of the sensor substrate 30 shown in FIGS. 10A to 10E corresponds to the exposure height at the plot positions shown in FIGS. 9A to 9E.

Here, the exposed height of the sensor substrate 30 is set by changing the thickness of the mold resin 40 without changing the thickness of the sensor substrate 30. Further, the thickness of the adhesive layer 80 between the surface 40a of the mold resin 40 and the strain-causing body 100 is constant at 0.11 mm (mm).

As a result of the simulation, the amount of strain is 34.0 μst at the exposure height of -100 μm shown in FIGS. 9 (a) and 10 (a), and the strain is distorted at the exposure height of -50 μm shown in FIGS. 9 (b) and 10 (b). When the amount is 36.9 μst and the exposure height shown in FIGS. 5 (c) and 6 (c) is 0 μm, the amount of strain is 39.2 μst.

Further, the strain amount is 42.0 μst at the exposure height +50 μm shown in FIGS. 9 (d) and 10 (d), and the strain amount is 53 at the exposure height +100 μm shown in FIGS. 9 (e) and 10 (e). It is 0 μst.

As described above, the amount of distortion increases as the exposure height of the surface 30a of the sensor substrate 30 from the surface 40a of the mold resin 40 increases (the detection sensitivity increases), and when the exposure height exceeds +50 μm, the amount of distortion further increases. (The detection sensitivity is higher).

If the thickness of the mold resin 40 is made too thin in order to increase the exposed height of the sensor substrate 30, the loop portion of the first bonding wire 61 and the like may be exposed from the mold resin 40. Therefore, it is desirable that the thickness of the mold resin 40 increases the exposed height of the sensor substrate 30 at a thickness at which the first bonding wire 61 is not exposed.

As described above, according to the present embodiment, the surface 30a of the sensor substrate 30 protrudes from the surface 40a of the mold resin 40, and the surface 40a of the mold resin 40 and the surface 30a of the sensor substrate 30 are the mounting surfaces of the strain-generating body 100. This makes it easier for the sensor board 30 to detect the strain from the strain-causing body 100 while firmly fixing it to the strain-causing body 100 around the sensor substrate 30. Therefore, it is possible to provide a strain sensor 1 having a configuration that makes it easy to detect the strain of the strain-causing body 100.

Although the present embodiment has been described above, the present invention is not limited to these examples. For example, a person skilled in the art appropriately adds, deletes, or changes the design of each of the above-described embodiments, or a combination of the features of the configuration examples of each embodiment as appropriate is also a gist of the present invention. Is included in the scope of the present invention as long as it is provided.

1 ... Distortion sensor 10 ... Package board 10a ... Board mounting surface 10b ... Pad surface 11 ... Electrode terminal 16 ... Pad part 20 ... Base board 20a ... Sensor mounting surface 25 ... Electrical wiring part 26 ... Seal 30 ... Sensor board 30a ... Surface 31 ... Displacement part 35 ... Piezo resistance element 35G ... Element group 35G1 ... First element group 35G2 ... Second element group 35G3 ... Third element group 35G4 ... Fourth element group 40 ... Mold resin 40a ... Surface 50 ... Circuit board 61 ... First 1 Bonding wire 62 ... Second bonding wire 80 ... Adhesive layer 80a ... First part 80b ... Second part 100 ... Distortion body F ... Flexible substrate GND ... Grounding potential SD ... Distortion direction V1 ... Output potential V2 ... Output potential VDD ... Power supply voltage t1 ... Thickness of the first part t2 ... Thickness of the second part

Claims

It is a strain sensor that detects the strain of the strain-causing body.
With the package board
A base board arranged on the package board and having an electric wiring part,
A sensor board arranged on the base board and having a plurality of piezo resistance elements,
A mold resin that covers the base substrate and the sensor substrate on the package substrate, and
Equipped with
A strain sensor characterized in that the surface of the sensor substrate protrudes from the surface of the mold resin, and the surface of the mold resin and the surface of the sensor substrate serve as a mounting surface for the strain-causing body.
The strain sensor according to claim 1, wherein the sensor substrate is provided separately from the mold resin.
The strain sensor according to claim 1 or 2, wherein the Young's modulus of the sensor substrate is higher than the Young's modulus of the molded resin.
The strain sensor according to any one of claims 1 to 3, wherein the longitudinal direction of the sensor substrate is substantially parallel to the strain direction of the strain-causing body.
The strain sensor according to any one of claims 1 to 4, wherein an adhesive layer is provided between the surface of the mold resin and the strain-causing body.
An adhesive layer is provided between the surface of the mold resin and the strain-causing body, and between the surface of the sensor substrate and the strain-causing body.
Claims 1 to 4 that the thickness of the adhesive layer from the surface of the sensor substrate to the strain-causing body is thinner than the thickness of the adhesive layer from the surface of the mold resin to the strain-causing body. The strain sensor according to any one of the above items.
The invention according to any one of claims 1 to 6, wherein a circuit board having a signal processing circuit for processing a signal output from the sensor board is provided between the package board and the base board. Distortion sensor.