JP2021081207A - Distortion detecting component, distortion detecting system, and distortion detecting method - Google Patents

Abstract

To provide a distortion detecting component capable of detecting an extremely small distortion of a substrate, and highly reliably verifying influence on a component mounted on a substrate in which the distortion has occurred, a distortion detecting system, and a distortion detecting method.SOLUTION: A distortion detecting component 11 can be mounted on a printed-wiring board 12 as a substrate. The distortion detecting component 11 comprises a first member 11A as a first portion made of a brittle material, and a second member 11B as a second portion which can apply, for example, a tensile stress to the first member 11A as a stress. A crack developing from the first member 11A can be advanced by applying a stress to the first member 11A by the second member 11B.SELECTED DRAWING: Figure 2

Description

The present invention relates to strain detection components, strain detection systems and strain detection methods.

As a method for detecting distortion generated in a printed wiring board or the like, a method disclosed in, for example, Japanese Patent Application Laid-Open No. 8-222480 (Patent Document 1) has been proposed. In the disclosure technique of JP-A-8-222480, a change in the resistance value of an evaluation component in which a plurality of ceramics on which a conductive resistor is printed is laminated is detected. As a result, the occurrence of distortion of the substrate is detected by detecting the occurrence of cracks in the ceramic.

Japanese Unexamined Patent Publication No. 8-222480

However, the following problems occur when trying to confirm the presence or absence of cracks by using the evaluation component for strain detection of the substrate on which the electronic component or the like is mounted, which is disclosed in Japanese Patent Application Laid-Open No. 8-222480. In the method of detecting the change in the resistance value of the evaluation component such as Japanese Patent Application Laid-Open No. 8-222480, when the strain is eliminated due to the minute cracks, the fracture surfaces come into contact with each other again and it is as if no cracks exist. May be in a state. If such a state occurs, it becomes difficult to detect this by inspection of changes in electrical characteristics or visual inspection.

The present invention has been made in view of the above problems. The purpose is to provide strain detection components, strain detection systems, and strain detection methods that can detect even the slightest distortion of a substrate and more reliably verify the effect of the strain on the components mounted on the substrate. That is.

The strain detection component according to the present disclosure can be mounted on a substrate. The strain detection component includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion. By applying stress to the first portion by the second portion, it is possible to develop cracks generated from the first portion.

A strain detection system according to the present disclosure includes a plurality of strain detection components mounted on a substrate at intervals from each other, and a detection circuit electrically connected to the plurality of strain detection components. Each of the plurality of strain detection components includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion. The first part is integrated with the first detection part, which causes cracks due to displacement in the direction along the main surface of the substrate, and the first detection part, and can be broken due to the cracks in the first detection part. It has a second detection unit that serves as. In the second portion, the second detection portion of the first portion can be broken by applying the stress. The strain detection component further includes a pair of support portions arranged so as to sandwich the first detection unit and the second detection unit.

In the strain detection method according to the present disclosure, a step of mounting the strain detection component on the substrate is performed. Another component mounting process is performed to mount components other than the strain detection component on the board. A process of detecting the presence or absence of cracks in the strain detection component is performed. The strain detecting component includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion. When the second portion applies stress to the first portion and the strain generated in the substrate causes a crack in the first portion, the crack propagates to the surface side of the first portion.

According to the present disclosure, a strain detection component, a strain detection system, and a strain detection method capable of detecting even a slight distortion of a substrate and more reliably verifying the influence on the component mounted on the substrate in which the distortion occurs. Can be provided.

It is a schematic plan view which shows the 1st example of the aspect of the substrate on which the strain detection component of Embodiment 1 is mounted. It is a schematic perspective view of the first example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 2nd example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 3rd example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a flowchart which shows the outline of the distortion detection method of the printed wiring board in Embodiment 1. FIG. It is a schematic perspective view which displays the appearance aspect of the printed wiring board on which a distortion detection component is mounted, and each parameter which causes distortion in a printed wiring board. It is a schematic perspective view which displays the design parameter of the distortion detection component which detects the distortion of a printed wiring board. It is a schematic plan view which shows the 2nd example of the aspect of the substrate on which the strain detection component of Embodiment 1 is mounted. It is a schematic front view which shows the mode in which a crack occurred in the strain detection component of Embodiment 1. FIG. It is a schematic front view which shows the modification of the appearance inspection of the strain detection component in Embodiment 1. FIG. It is a schematic perspective view of the first modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the second modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. 1. It is a schematic perspective view of the 3rd modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 4th modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 5th modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the sixth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. 1. It is a schematic perspective view of the 7th modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 8th modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the 9th modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the tenth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic perspective view of the eleventh modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. It is a schematic plan view which shows the mode of the substrate on which the strain detection component of Embodiment 2 is mounted. It is a schematic perspective view of the first example of the region C on which the strain detection component of the first example of Embodiment 2 is mounted, which is surrounded by a dotted line in FIG. 22. FIG. 22 is a schematic perspective view of a second example of the region C on which the strain detection component of the first example of the second embodiment, which is surrounded by a dotted line in FIG. 22, is mounted. FIG. 23 is a schematic plan view and a schematic front view showing design parameters of the strain detection component of FIG. 23. It is a schematic diagram which shows the mode in which the 2nd detection part of the strain detection component of FIG. 23 which crack occurred in the 1st detection part is broken by a magnet. It is a schematic front view which shows the mode of the substrate on which the strain detection component of the 2nd Example of Embodiment 2 is mounted. FIG. 27 is a schematic plan view and a schematic front view showing design parameters of the strain detection component of FIG. 27. It is a schematic plan view and a schematic front view which displays the deformation example of the distortion detection component of FIG. 23. FIG. 27 is a schematic plan view and a schematic front view showing a modified example of the strain detection component of FIG. 27. It is the schematic which shows the structure of the distortion detection system of Embodiment 2. It is a schematic plan view which shows the mode of the substrate on which the strain detection component of Embodiment 3 is mounted. FIG. 3 is a schematic perspective view of a region D in which a strain detection component surrounded by a dotted line in FIG. 32 is mounted. FIG. 3 is a schematic perspective view showing each component of the strain detection component in an exploded manner in order to show the configuration of the strain detection component of the third embodiment in FIG. 33. It is the schematic which shows the structure of the distortion detection system of Embodiment 3.

Hereinafter, each embodiment will be described with reference to the drawings. For convenience of explanation, the X direction, the Y direction, and the Z direction are introduced.

Embodiment 1.
<Basic configuration>
FIG. 1 is a schematic plan view showing a first example of a mode of a substrate on which the strain detection component of the first embodiment is mounted. With reference to FIG. 1, the strain detection component 11 of the present embodiment can be mounted on a printed wiring board 12 as a substrate. Therefore, in FIG. 1, the strain detection component 11 is mounted on the printed wiring board 12. For example, generally known wiring is connected to the surface of the printed wiring board 12. Further, the connector 13 is inserted into the printed wiring board 12 so as to penetrate from the main surface on the upper side in the Z direction, which is one main surface, to the main surface on the lower side in the Z direction, which is the other main surface.

The printed wiring board 12 including the wiring or the connector 13 as described above is incorporated into a generally known component (not shown) or the like. Distortion may occur in the printed wiring board 12 during the process of connecting the wiring to the printed wiring board 12, the process of inserting the connector 13, the process of incorporating the printed wiring board 12 into other parts, and the like. The strain detection component 11 is mounted on one of the main surfaces of the printed wiring board 12 along the XY plane, for example, in order to detect such distortion of the printed wiring board 12.

Of the printed wiring board 12, for example, the connector peripheral portion 12a is a region in which the printed wiring board 12 is likely to be distorted in the process of inserting the connector 13. The connector peripheral portion 12a is an area adjacent to the connector 13 so as to surround the connector 13 when the printed wiring board 12 is viewed in a plan view. Further, the substrate corner portion 12b, which is a region adjacent to each apex when the printed wiring board 12 is viewed in a plan view, is also a region in which the printed wiring board 12 is likely to be distorted during each of the above steps. Further, the component peripheral portion 12c adjacent to the electronic component 14 such as the MLCC (Multi-Layer Ceramic Capacitor) attached to the printed wiring board 12 so as to surround the electronic component 14 is also a region in which the printed wiring board 12 is likely to be distorted.

The strain detection component 11 is preferably mounted on the peripheral portion 12c of the printed wiring board 12 as shown in FIG. This is because the peripheral portion 12c of the component is liable to be distorted, and the substrate bending resistance of the printed wiring board 12 is lower than that of other regions. The low substrate bending resistance means that the stress applied to the printed wiring board 12 when the electronic component 14 such as the MLCC is cracked is low. However, the distortion detection component 11 may be mounted on the connector peripheral portion 12a or the board corner portion 12b of the printed wiring board 12.

FIG. 2 is a schematic perspective view of a first example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 2, the strain detection component 11 includes a first member 11A as a first portion and a second member 11B as a second portion. The first member 11A is provided on the upper side of the second member in the Z direction. The first member 11A is made of a brittle material such as glass or ceramic. Here, the brittle material means a material that is more brittle and more fragile than a metal material. The second member 11B is at least partially in contact with the first member 11A, and stress can be applied to the first member 11A. In FIG. 2, for example, the second member 11B applies tensile stress to the first member 11A. As will be described later, the second member 11B develops a crack generated from the first member 11A by applying a stress such as a tensile stress to the first member 11A.

The second member 11B is a pedestal-shaped member made of a material having a tensile strength equal to or greater than that of the brittle material of the first member 11A. That is, the second member 11B is made of a material having a tensile strength higher than that of the brittle material of the first member 11A. Specifically, the second member 11B is preferably made of a material that is less likely to break than the first member 11A. However, the second member 11B may be made of the same material as the first member 11A.

The above tensile stress, that is, the tensile strength of the material, is measured by a tensile test based on any of JIS Z 2241, JIS Z 2201, JIS K 6251, JIS K 7161, JIS K 7139, JIS K 7054, and JIS R 1602. The value is referenced.

The first member 11A and the second member 11B on the lower side in the Z direction are bonded at an adhesive portion. However, as shown in FIG. 2, a non-adhesive portion 11C in which the first member 11A and the second member 11B are not adhered is formed in a region inside the adhesive portion in at least one direction, for example, the X direction. There is. In other words, in FIG. 2, the first member 11A and the second member 11B are fixed to each other by, for example, an adhesive on the left side portion and the right side portion in the X direction in a plan view, which are the portions where the first member 11A and the second member 11B contact each other. ing.

As shown in FIG. 2, the non-adhesive portion 11C is formed on the inner side, that is, the central portion sandwiched between the left side portion and the right side portion in the X direction in the portion where the first member 11A and the second member 11B come into contact with each other. There is. However, the non-adhesive portion 11C may be formed inside the central portion in the Y direction, that is, the portion where the first member 11A and the second member 11B in the Y direction come into contact with each other. Since the adhesive is not applied to the non-adhesive portion 11C, the first member 11A and the second member 11B are not adhered to each other in the non-adhesive portion 11C. In FIG. 2, even in the non-adhesive portion 11C, the first member 11A and the second member 11B may be in contact with each other as in the region outside the X direction.

In the first example of FIG. 2, a copper foil pad 16 is formed on, for example, a component peripheral portion 12c on one main surface of the printed wiring board 12. As an example, the copper foil pads 16 of FIG. 2 are formed in pairs at intervals in the X direction, but the present invention is not limited to this mode. The strain detection component 11 is preferably connected on the copper foil pad 16 so as to straddle the pair of copper foil pads 16. It is preferable that the lowermost surface of the second member 11B on the lower side in the Z direction of the strain detection component 11 is connected on the respective surfaces of the pair of copper foil pads 16. The connection between the strain detection component 11 and the copper foil pad 16 is preferably made by an adhesive 17, but is not limited to this.

FIG. 3 is a schematic perspective view of a second example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 3, FIG. 3 is essentially the same as FIG. However, in FIG. 3, the copper foil pad 16 is not formed on one main surface of the printed wiring board 12. As shown in FIG. 3, the strain detection component 11 may be directly connected to one main surface of the printed wiring board 12 by the adhesive 17.

FIG. 4 is a schematic perspective view of a third example of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 4, FIG. 4 is essentially the same as FIG. However, in FIG. 4, a defective portion is formed in a portion where the second member 11B constituting the strain detection component 11 faces the first member 11A, in which the second member 11B is partially missing. The defect portion is formed so as to have a concave shape, for example. This defective portion is located in the central portion in the Y direction in the plan view of the portion where the first member 11A and the second member 11B are in contact, that is, the region inside the portion where the first member 11A and the second member 11B are in contact with each other. , The non-adhesive portion 11C is formed.

The defective portion is formed so that at least one of the first member 11A and the second member 11B is partially missing from the portion where the first member 11A constituting the strain detection component 11 faces the second member 11B. May be good. Alternatively, the defective portion may be formed on both the first member 11A and the second member 11B. In any case, the strain detection component 11 may have a configuration in which a non-adhesive portion 11C as a defective portion is formed in at least one of the first member 11A and the second member 11B. In the non-adhesive portion 11C, the first member 11A and the second member 11B are not adhered to each other. In the region other than the non-adhesive portion 11C in FIG. 4, the first member 11A and the second member 11B may be adhered with an adhesive or may be fitted to each other.

<Distortion detection method>
Next, a method of detecting distortion of the printed wiring board 12 by the distortion detecting component of the first embodiment will be described with reference to FIGS. 5 to 9 and, if necessary, FIG. 1 and the like.

FIG. 5 is a flowchart showing an outline of the distortion detection method of the printed wiring board according to the first embodiment. With reference to FIG. 5, first, the strain detection component 11 is mounted on the printed wiring board 12 shown in FIG. 1 as a substrate (S10). That is, it is a step in which the strain detection component 11 is mounted on, for example, one of the main surfaces of the printed wiring board 12 by adhesion or the like. A single strain detection component 11 may be mounted as shown in FIG. 5, but a plurality of strain detection components 11 may be mounted.

FIG. 6 is a schematic perspective view showing the appearance of the printed wiring board on which the strain detection component is mounted and each parameter that causes distortion in the printed wiring board. With reference to FIG. 6, a multilayer ceramic capacitor or the like as the electronic component 14 shown in FIG. 1 is mounted on the printed wiring board 12 in which the strain detection component 11 detects distortion. For example, in a multilayer ceramic capacitor, distortion is applied due to distortion occurring in the printed wiring board 12 while it is mounted on the printed wiring board 12. The multilayer ceramic capacitor is cracked when a distortion of about 500 μST or more and 2500 μST or less is applied in the state of being mounted on the printed wiring board 12. As parameters that cause distortion in the printed wiring board 12 of FIG. 6, the thickness in the Z direction is h, the depth width in the Y direction is w, and the distance between a pair of fulcrums in the X direction is l. Further, let ε be the strain applied to the printed wiring board 12, and let E be the elastic modulus of the printed wiring board 12. At this time, the load P applied to the printed wiring board 12 is

It is represented by. For example, when each of the above parameters of the printed wiring board 12 of FIG. 6 has the values shown in Table 1 below, the load P of the printed wiring board 12 is 25.6 N or more and 128 N or less. Table 1 shows the design parameters of each part of the printed wiring board 12 for causing distortion in the printed wiring board 12.

Next, assuming that the strain detection component 11 capable of detecting the distortion when a strain of 1000 μST or more is applied to the printed wiring board 12, for example, is mounted on the printed wiring board 12, the strain detection component 11 The value of the design parameter of is obtained.

FIG. 7 is a schematic perspective view showing the design parameters of the distortion detection component that detects the distortion of the printed wiring board. That is, in FIG. 7, the dimensional parameters of each part of the strain detection component 11 are displayed with respect to the schematic perspective view of FIG. With reference to FIG. 7, as a design parameter of the strain detection component 11, the width of the entire strain detection component 11 in the X direction is La. Let Lb be the width of the adhesive portion between the first member 11A and the second member 11B in the X direction. Let H be the height of the first member 11A in the Z direction, and let D be the depth of the entire strain detection component 11 in the Y direction. Let σ be the material tensile strength of the strain detection component 11, and let P be the load applied to the strain detection component 11. At this time, the condition for cracking in the strain detection component 11 is

It is represented by. Further, for example, when the strain generated on the printed wiring board 12 is 1000 μST, the load applied to the printed wiring board 12 is 51.2 N or more. As described above, when the strain detection component 11 is formed of barium titanate as a material, the above parameters of the strain detection component 11 have the values shown in Table 2 below.

It is preferable that any material selected from the group consisting of barium titanate, calcium zirconate, fine ceramics, alumina, and quartz glass is used for the strain detection component 11. All of these are brittle materials having a material tensile strength of 1500 MPa or less.

The method for setting the design parameters of the strain detection component 11 more easily is as follows. The material constituting the strain detection component 11 is preferably the same brittle material as the material constituting the surface layer of the electronic component 14 mounted on the printed wiring board 12. Of the strain detection components 11, both the first member 11A and the second member 11B may be made of the brittle material. Alternatively, of the above, only the first member 11A may be made of the brittle material.

The numerical values of the width La of the entire strain detection component 11 in the X direction and the depth D of the entire strain detection component 11 in the Y direction are the dimensions of the brittle material portion of the electronic component 14 mounted on the strain detection component 11. Make it equal. The electronic component 14 here is a monolithic ceramic capacitor or the like. The width Lb of the adhesive portion between the first member 11A and the second member 11B in the X direction is equal to the width of the adhesive portion between the brittle material portion of the electronic component 14 and the printed wiring board 12 in the X direction. The width Lb may be equal to the width in the X direction of the bonded portion between the copper foil pad 16 formed on the printed wiring board 12 and the brittle material portion of the electronic component 14. The height H of the first member 11A in the Z direction is about the same as the thickness of the brittle material portion of the electronic component 14 in the Z direction. By determining the dimensions of each part of the strain detection component 11 as described above, the resistance to cracking of the strain detection component 11 becomes equal to or less than the resistance to cracking of the brittle material portion of the multilayer ceramic capacitor.

In the initial state in which the strain detection component 11 is not mounted on the printed wiring board 12, tensile stress is already generated in the first member 11A and compressive stress is already generated in the second member 11B. Therefore, before the step (S10) in which the strain detection component 11 is mounted, a tensile stress is already applied in the first member 11A, and a compressive stress is already applied in the second member 11B. When the first member 11A and the second member 11B are bonded to each other in the step (S10), a tensile stress is further applied to the first member 11A and a compressive stress is further applied to the second member 11B. In this state, it is preferable that the first member 11A and the second member 11B are adhered to each other. Specifically, for example, the first member 11A is adhered to the second member 11B in a state where a tensile stress is applied. At this time, tensile stress is applied to the first member 11A by a tensile compression tester or the like. Alternatively, for example, the second member 11B is adhered to the first member 11A in a state where a compressive stress is applied. At this time, tensile stress is applied to the second member 11B by a tensile compression tester or the like. Alternatively, both may be adhesively fixed in a state where a tensile stress is applied to the first member 11A and a compressive stress is applied to the second member 11B.

Further, the following method may be used. For example, the second member 11B of the strain detection component 11 is adhered to the first member 11A in a heated state, and both are cooled after the adhesion. The second member 11B expanded at a high temperature due to heating does not completely return to its original dimensions even after being adhered to the first member 11A. Therefore, a compressive stress is applied as a residual stress in the second member 11B. As a result, both can be bonded so that tensile stress is applied to the first member 11A and compressive stress is applied to the second member 11B.

Contrary to the above, both may be adhered so that compressive stress is applied in the first member 11A and tensile stress is applied in the second member 11B. In this case, the second member 11B may be made of a material that is more fragile than the first member 11A.

Next, the method of adhering the strain detection component 11 to the printed wiring board 12 in the step (S10) is as follows. The adhesive 17 for adhering the second member 11B of the strain detection component 11 to the printed wiring board 12 is preferably an epoxy-based or urethane-based resin material. However, as long as the strain detection component 11 and the printed wiring board 12 can be adhered to each other, the adhesive 17 may be made of a material other than the above. For example, solder may be used as the adhesive 17 in addition to the above. When the adhesive 17 is solder, a plating portion is provided on the strain detection component 11, and the portion is adhered to the solder adhesive 17. However, the plated portion is formed in a region other than the surface of the strain detection component 11. That is, the plated portion is formed on a separate member (not shown) as a separate body from the strain detection component 11.

The printed wiring board 12 on which the strain detection component 11 is mounted has anisotropy in how distortion is generated when a load is applied. That is, when the printed wiring board 12 has a rectangular planar shape along the XY plane as shown in FIG. 1, the printed wiring board 12 is easily bent along the X direction of FIG. 1 along the long side of the rectangle. That is, the printed wiring board 12 of FIG. 1 has a low substrate bending resistance in the X direction. Therefore, it is preferable that the strain detection component 11 is mounted on the main surface of the printed wiring board 12 of FIG. 1 so that the maximum strain is generated along the X direction.

As shown in FIG. 1, the strain detection component 11 is placed on the printed wiring board 12 so that the long side direction of the rectangle in the plan view of the strain detection component 11 is along the X direction in which the substrate bending resistance of the printed wiring board 12 is low. It may be implemented. Here, FIG. 8 is a schematic plan view showing a second example of the aspect of the substrate on which the strain detection component of the first embodiment is mounted. With reference to FIG. 8, this is basically the same as FIG. 1, but the orientation in which the distortion detection component 11 in a plan view is mounted is different. Specifically, in FIG. 8, the strain detection component 11 is mounted in the region B surrounded by the dotted line.

In FIG. 8, the strain detection component 11 is placed on one main surface of the printed wiring board 12 so that the rectangular diagonal line of the strain detection component 11 in a plan view is along the X direction, which is the long side direction of the printed wiring board 12. It is implemented. The direction of the maximum dimension of the strain detection component 11 in a plan view is a direction along the diagonal line. Therefore, the distortion detection component 11 generates maximum distortion along the diagonal direction. Therefore, it is more preferable that the strain detection component 11 is mounted so that this direction is the long side direction in which the substrate bending resistance of the printed wiring board 12 is low. A plurality of strain detection components 11 may be mounted on the printed wiring board 12 so as to be in both the direction shown in FIG. 1 and the direction shown in FIG.

Although the above is a general theoretical theory, it is also possible to obtain knowledge by measurement regarding the direction in which the maximum strain of the printed wiring board 12 and the strain detection component 11 is generated. In that case, it is more preferable that the printed wiring board 12 and the strain detection component 11 are bonded to each other so that the directions of the maximum strains obtained by the measurement thereof are substantially the same. The direction in which the maximum strain is generated is preferably the corresponding direction if there is knowledge measured in advance with a strain gauge or the like. If there is no knowledge of the direction in which the maximum strain occurs, the direction may be calculated using simulation or the like. At this time, the strain gauge may be adhered to the strain detection component 11 or the like, and the reaction of the strain gauge may be examined to calculate the direction in which the strain detection component 11 or the like is likely to be distorted. A plurality of strain detection components 11 may be installed in places where distortion is likely to occur, such as the connector peripheral portion 12a, the substrate corner portion 12b, and the component peripheral portion 12c in FIG.

The method of adhering the strain detection component 11 on the printed wiring board 12 in the step (S10) is as follows. For example, the adhesive 17 is applied on one main surface of the printed wiring board 12 or on the copper foil pad 16 arranged on the one main surface. The strain detection component 11 is arranged on the strain detection component 11 and is adhered to the printed wiring board 12. At this time, care is taken not to cause cracks in the strain detection component 11.

With reference to FIG. 5 again, a component mounting step of mounting the connector 13 and the electronic component 14 which are other components other than at least one strain detection component 11 is performed on the printed wiring board 12 (S20). .. This step (S20) also includes, for example, a step of connecting wiring to the printed wiring board 12. Either the step (S10) or the step (S20) of FIG. 5 may be performed first. However, if the process (S10) is performed first and the process (S20) is performed later, there is an advantage that the strain generated by the stress of the printed wiring board 12 when the electronic component 14 or the like is mounted in the process (S20) can be detected. There is. Therefore, it is more preferable that the step (S10) is performed first.

As shown in FIG. 5, the presence or absence of cracks in the strain detection component 11 is detected (S30). Here, when the process (S10) is performed first, the strain detection component 11 due to the distortion of the printed wiring board 12 when the electronic component 14 or the like other than the distortion detection component 11 in the process (S20) is mounted is reached. The presence or absence of cracks is detected.

FIG. 9 is a schematic front view showing a mode in which a crack is generated in the strain detection component of the first embodiment. With reference to FIG. 9, in the strain detection component 11 of the present embodiment, for example, if the process (S10) is performed first and the process (S20) is performed later, the connector 13 is inserted or inserted in the process (S20). The printed wiring board 12 is distorted due to mounting of the electronic component 14 or the like. For example, when the magnitude of the strain of the printed wiring board 12 exceeds the reference value, a crack occurs from the end portion of the non-adhesive portion 11C in the X direction or a position adjacent thereto as a starting point toward the upper side in the Z direction in the drawing. The mode of the crack is, for example, any of the cracks Cka, Ckb, Ckc, and CKD shown by the dotted line in FIG. 9, but is not limited thereto. Further, two or more cracks may occur among the cracks Cka to CKD. Cracks may extend in a direction slightly inclined with respect to the Z direction, such as cracks Cka to Cked.

The second member 11B applies, for example, tensile stress to the first member 11A. When a crack is generated in the first member 11A due to the strain generated in the printed wiring board 12, the crack grows on the surface side of the first member 11A, that is, on the upper side in the Z direction due to the above-mentioned tensile stress.

In the step (S30), the presence or absence of cracks Cka to CKD is confirmed. As a means for this, for example, a visual inspection by a microscope, visual inspection, or AOI (Automated Optical Inspection) is performed. The presence or absence of cracks in the strain detection component 11 confirms the presence or absence of a history that strain exceeding the substrate bending resistance of the printed wiring board 12 has occurred up to that point. As described above, in the present embodiment, in the step (S30), the first member 11A included in the first portion of the strain detection component 11 is visually recognized. As a result, the presence or absence of cracks in the first member 11A is detected (S31A).

FIG. 10 is a schematic front view showing a modified example of the appearance inspection of the strain detection component according to the first embodiment. When it is difficult to visually determine the presence or absence of cracks by visual inspection by visual inspection with reference to FIG. 10, the irradiation angle of light used for visual inspection, which is indicated by a thick arrow in FIG. 10, is adjusted. Specifically, it is preferable that the irradiation angle α of the light on the strain detection component 11 with respect to the normal is 80 ° or less, which exceeds 0 °, for example. Among these, the irradiation angle α is particularly preferably 10 ° or more, and more preferably 30 ° or more. Further, the irradiation angle α is particularly preferably 60 ° or less, and more preferably 50 ° or less. By irradiating the normal line with light from an oblique direction in this way, the probability of finding a crack can be improved. This is because when the light is incident from an oblique direction, the reflected light due to a fine shape such as a step on the wall surface of the gap formed by the crack does not enter the microscope or the like, and the light and darkness due to the gap can be easily recognized. The above light may be incident on the strain detection component 11 from a plurality of places.

The spotlight as the light in FIG. 10 may be monochromatic light or white light. When the inside of the printed wiring board 12 does not contain a light-shielding material such as copper foil, light may be irradiated from the back surface side of the printed wiring board 12, that is, the lower side in the Z direction. Alternatively, the presence or absence of cracks may be confirmed using a so-called dark field microscope.

<Effect>
Next, the action and effect of the present embodiment will be described.

The strain detection component 11 according to the disclosure of the present embodiment can be mounted on the printed wiring board 12 as a substrate. The strain detection component 11 has a first member 11A as a first portion made of a brittle material and a second portion as a second portion capable of applying, for example, tensile stress as a stress to the first member 11A. It includes two members 11B. By applying stress to the first member 11A by the second member 11B, it is possible to develop cracks generated from the first member 11A.

The first member 11A is made of a brittle material, and the second member 11B applies, for example, a stress in the tensile direction to the first member 11A. Therefore, even a slight stress causes cracks in the first member 11A. That is, according to the present embodiment, cracks are also generated by a very small distortion generated in the printed wiring board 12 on which the component is mounted. The generated cracks grow due to tensile stress or the like, which is the stress on the first member 11A, and the width thereof is wide and easy to confirm. In the present embodiment, the fractured portion of the strain detection component 11 due to the crack once formed is subsequently maintained. Therefore, in the present embodiment, the possibility that the fractured surfaces of the generated cracks come into contact with each other again and the cracks do not exist and cannot be confirmed is reduced. From the above, in the present embodiment, even a very slight distortion generated in the printed wiring board 12 on which each component is mounted can be sensitively detected. In addition, it is possible to reliably detect whether or not a crack has occurred by that time regardless of the timing of the inspection after the crack has occurred. Therefore, according to the present embodiment, when the distortion of the printed wiring board 12 is large even for a moment, the influence on the electronic components 14 mounted on the printed wiring board 12 and the like can be verified with higher reliability.

In the strain detection component 11, the brittle material is either glass or ceramic. The second member 11B is made of a material having a tensile strength equal to or higher than that of the brittle material. A non-adhesive portion in which the first member 11A and the second member 11B are not adhered to a region inside the adhesive portion between the first member 11A and the second member 11B in at least one direction in a plan view, for example, the X direction. 11C is formed. Such a configuration is preferable.

Since the second member 11B has a tensile strength equal to or higher than that of the brittle material, the first member 11A cracks more preferentially than the second member 11B. Therefore, the first member 11A is more easily cracked than the second member 11B. Further, due to the strong tensile strength applied by the second member 11B to the first member 11A, a larger tensile stress is generated in the first member 11A. Therefore, when a crack origin occurs in the first member 11A, a wide crack easily develops from the origin. Therefore, cracks generated in the first member 11A can be more easily confirmed. As described above, even a slight distortion of the printed wiring board 12 can cause a clear and large crack in the first member 11A. Therefore, a slight distortion of the printed wiring board 12 can be detected with high accuracy.

Further, a non-adhesive portion 11C is formed in which the first member 11A and the second member 11B are not adhered to each other. As a result, the starting point of the crack generated in the first member 11A is limited to the boundary portion between the non-adhesive portion 11C and the adhesive portion between the first member 11A and the second member 11B outside the non-adhesive portion 11C. Therefore, the range to be confirmed at the time of visual inspection is limited, and confirmation becomes easy.

The non-adhesive portion 11C is arranged inside the adhesive portion in the X direction, that is, on the center side. As a result, for example, when a tensile stress is applied to the first member 11A, the adhesive portion with the second member 11B does not peel off. Therefore, the load due to the tensile stress is concentrated on the non-adhesive portion 11C, and cracks are generated.

Even when the first member 11A and the second member 11B are cracked at the same time, the amount of distortion of the printed wiring board 12 can be detected. Therefore, the tensile strengths of the first member 11A and the second member 11B with respect to the material may be the same.

In the strain detection component 11, at least one of the first member 11A and the second member 11B is formed with a defect portion in which at least one of the first member 11A and the second member 11B is partially missing. Such a configuration is preferable.

If a defective portion is formed, the portion functions in the same manner as the non-adhesive portion 11C. Therefore, as compared with the non-adhesive portion 11C as a region to which the adhesive is not supplied, the position of the non-adhesive portion 11C is more easily understood in the appearance of the defective portion. Therefore, it becomes easier to identify the position to be inspected at the time of visual inspection.

In the distortion detection method according to the disclosure of the present embodiment, a step of mounting the distortion detection component 11 on the printed wiring board 12 as a substrate is performed. Another component mounting process is performed in which components other than the strain detection component 11 are mounted on the printed wiring board 12. A step of detecting the presence or absence of cracks in the strain detection component 11 is performed. The strain detecting component 11 includes a first member 11A as a first portion made of a brittle material and a second member 11B as a second portion capable of applying stress to the first member 11A. When the second member 11B applies a stress such as a tensile stress to the first member 11A and the strain generated in the printed wiring board 12 causes a crack in the first member 11A, a crack is generated on the surface side of the first member 11A. Make progress.

The first member 11A is made of a brittle material, and the second member 11B applies a stress in the tensile direction to the first member 11A, for example. Therefore, even a slight stress causes cracks in the first member 11A. That is, according to the present embodiment, cracks are also generated by a very small distortion generated in the printed wiring board 12 on which the component is mounted. The generated cracks propagate toward the surface side of the first member 11A due to tensile stress or the like, which is a stress on the first member 11A, and the width thereof is wide and easy to confirm. In the present embodiment, the fractured portion of the strain detection component 11 due to the crack once formed is subsequently maintained. Therefore, in the present embodiment, the possibility that the fractured surfaces of the generated cracks come into contact with each other again and the cracks do not exist and cannot be confirmed is reduced. From the above, in the present embodiment, even a very slight distortion generated in the printed wiring board 12 on which each component is mounted can be sensitively detected. In addition, it is possible to reliably detect whether or not a crack has occurred by that time regardless of the timing of the inspection after the crack has occurred. Therefore, according to the present embodiment, when the distortion of the printed wiring board 12 is large even for a moment, the influence on the electronic components 14 mounted on the printed wiring board 12 and the like can be verified with higher reliability.

In the above strain detection method, the first member 11A and the second member 11A and the second member 11A and the second member 11A are in a state where a tensile stress is applied to the first member 11A and a compressive stress is applied to the second member 11B before the process of mounting the strain detection component 11. The members 11B are adhered to each other. That is, tensile stress is generated in the first member 11A of the strain detection component 11 even when it is not mounted on the printed wiring board 12. Compressive stress is generated in the second member 11B even when it is not mounted on the printed wiring board 12. It is preferable that such a process is performed. That is, in the strain detection component 11 of the present embodiment, residual stress of tensile stress has already been generated in the first member 11A in the initial state before being mounted on the printed wiring board 12, and the strain detection component 11 has a residual stress in the second member 11B. Is preferably manufactured so as to have a residual stress of compressive stress.

From the beginning, a strain detection component 11 is formed in a state where a residual stress of tensile stress is applied in the first member 11A and a residual stress of compressive stress is applied in the second member 11B. Therefore, in the first member 11A of the strain detection component 11 mounted on the printed wiring board 12, the tensile stress due to the strain of the printed wiring board 12 is added with the tensile stress as the residual stress from the beginning, and the tensile stress is very large. Become. Similarly, in the second member 11B of the strain detection component 11 mounted on the printed wiring board 12, the compressive stress due to the strain of the printed wiring board 12 is added with the compressive stress as the residual stress from the beginning, and the compressive stress is very high. growing. Therefore, even when the printed wiring board 12 has a slight strain, the first member 11A is clearly cracked due to the large tensile stress exerted on the first member 11A by the large compressive stress of the second member 11B. After that, large cracks that are easily visible are likely to occur in the first member 11A. Therefore, the reliability of the distortion evaluation result of the printed wiring board 12 is further improved.

In the distortion detection method, in the detection step, the presence or absence of cracks in the first portion is detected by visually recognizing the first portion. It is preferable that such a process is performed. If the breaking width of the crack is sufficiently wide and the crack is extended sufficiently long, the presence or absence of the crack can be easily detected visually.

In the above embodiment, as shown in FIG. 8, along the long side direction in which the substrate bending resistance of the printed wiring board 12 is the lowest, the strain detection component 11 is the longest hand direction in which cracks are most likely to grow, for example, a flat surface. It is preferably mounted so that the diagonal direction in the visual direction extends. For example, if the printed wiring board 12 is mounted so that the short side of the rectangle in the plan view of the strain detection component 11 extends along the longitudinal direction in which the substrate bending resistance is the lowest, the strain detection component 11 has a size that can be sufficiently detected. Cracks are less likely to be formed. On the contrary, if the strain detection component 11 is mounted so that the direction in which the crack of the strain detection component 11 is likely to grow extends in the direction in which the substrate bending resistance of the printed wiring board 12 is low, it is sensitive to the distortion of the printed wiring board 12. Cracks are likely to occur and propagate in the strain detection component 11.

Summarizing the above, in the present embodiment, even when a crack occurs in the first member 11A of the strain detection component 11 due to a slight strain of the printed wiring board 12, the crack is generated by applying tensile stress. Can be advanced. Therefore, a slight distortion of the printed wiring board 12 can be detected with high accuracy.

<Modification example>
In order to improve the visibility of the generated cracks of the strain detection component 11 and make it easier to identify the crack generation position, the strain detection component 11 may have the configuration of each of the following modifications.

FIG. 11 is a schematic perspective view of a first modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 11, FIG. 11 is essentially the same as FIG. However, in FIG. 11, the paint coating surface 11D is formed on the uppermost surface of the first member 11A in the Z direction. The paint-coated surface 11D is coated with a paint having a color scheme different from that of the other parts of the first member 11A, that is, a color that is recognized by a normal viewer as a completely different color. More specifically, for example, when the brittle material portion of the first member 11A is white, the paint coating surface 11D is black. Such a configuration may be used.

FIG. 12 is a schematic perspective view of a second modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 12, FIG. 12 is essentially the same as FIG. However, in FIG. 12, a non-adhesive portion 11C is formed as a defective portion in which the first member 11A faces the second member 11B. The non-adhesive portion 11C has a triangle when viewed from the negative side in the Y direction, which extends along the Y direction and extends over the entire first member 11A. Further, the non-adhesive portion 11C is formed in a pair at the central portion of the first member 11A in the X direction at intervals in the X direction. Further, a groove portion 11E is formed on the uppermost surface of the first member 11A so as to overlap with the non-adhesive portion 11C in a plane. A pair of groove portions 11E is formed in the same manner as the non-adhesive portion 11C. The groove portion 11E has a triangular shape when viewed from the front, extends along the Y direction, and extends over the entire first member 11A. Such a configuration may be used.

FIG. 13 is a schematic perspective view of a third modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 13, FIG. 13 is essentially the same as FIG. However, in FIG. 13, the groove portion 11E is not formed, and only a pair of non-adhesive portions 11C are formed in the same manner as in FIG. Such a configuration may be used.

FIG. 14 is a schematic perspective view of a fourth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 14, FIG. 14 is essentially the same as FIG. However, in FIG. 14, one non-adhesive portion 11C larger than that in FIG. 12 is formed at the central portion of the first member 11A in the X direction. The non-adhesive portion 11C has a triangle when viewed from the negative side in the Y direction, which extends along the Y direction and extends over the entire first member 11A. Further, a groove portion 11E is formed on the uppermost surface of the first member 11A so as to overlap with the non-adhesive portion 11C in a plane. The groove portion 11E has a triangular shape when viewed from the front, extends along the Y direction, and extends over the entire first member 11A. Such a configuration may be used.

FIG. 15 is a schematic perspective view of a fifth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 15, FIG. 15 is essentially the same as FIG. However, in FIG. 15, the groove portion 11E is not formed, and only a single non-adhesive portion 11C is formed in the same manner as in FIG. Such a configuration may be used.

FIG. 16 is a schematic perspective view of a sixth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 16, FIG. 16 is essentially the same as FIG. However, in FIG. 12, a non-adhesive portion 11C is formed as a defective portion in which the first member 11A faces the second member 11B. The non-adhesive portion 11C has a quadrangle when viewed from the negative side in the Y direction, which extends along the Y direction and extends over the entire first member 11A. Further, the non-adhesive portion 11C is formed in a pair at the central portion of the first member 11A in the X direction at intervals in the X direction. Further, a groove portion 11E is formed on the uppermost surface of the first member 11A so as to overlap with the non-adhesive portion 11C in a plane. A pair of groove portions 11E is formed in the same manner as the non-adhesive portion 11C. The groove portion 11E has a quadrangular shape when viewed from the front, extends along the Y direction, and extends over the entire first member 11A. Such a configuration may be used.

FIG. 17 is a schematic perspective view of a seventh modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 17, FIG. 17 is essentially the same as FIG. However, in FIG. 17, the groove portion 11E is not formed, and only a pair of non-adhesive portions 11C are formed in the same manner as in FIG. Such a configuration may be used.

FIG. 18 is a schematic perspective view of an eighth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 18, FIG. 18 is essentially similar to FIG. However, in FIG. 18, one non-adhesive portion 11C is formed at the central portion of the first member 11A in the X direction. The non-adhesive portion 11C has a quadrangle when viewed from the negative side in the Y direction, which extends along the Y direction and extends over the entire first member 11A. Further, a groove portion 11E is formed on the uppermost surface of the first member 11A so as to overlap with the non-adhesive portion 11C in a plane. The groove portion 11E has a quadrangular shape when viewed from the front, extends along the Y direction, and extends over the entire first member 11A. Such a configuration may be used.

FIG. 19 is a schematic perspective view of a ninth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 19, FIG. 19 is essentially similar to FIG. However, in FIG. 19, the groove portion 11E is not formed, and only a single non-adhesive portion 11C is formed in the same manner as in FIG. Such a configuration may be used.

FIG. 20 is a schematic perspective view of a tenth modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 20, FIG. 20 is essentially the same as FIG. However, in FIG. 20, a non-adhesive portion 11C is formed as a defective portion in which the first member 11A faces the second member 11B. The non-adhesive portion 11C has a semicircular shape when viewed from the negative side in the Y direction, which extends along the Y direction and extends over the entire first member 11A. Further, the non-adhesive portion 11C is formed in a pair at the central portion of the first member 11A in the X direction at intervals in the X direction. Further, a groove portion 11E is formed on the uppermost surface of the first member 11A so as to overlap with the non-adhesive portion 11C in a plane. A pair of groove portions 11E is formed in the same manner as the non-adhesive portion 11C. The groove portion 11E has a semicircular shape when viewed from the front, extends along the Y direction, and extends over the entire first member 11A. Such a configuration may be used.

FIG. 21 is a schematic perspective view of an eleventh modification of the region A on which the strain detection component is mounted, which is surrounded by a dotted line in FIG. With reference to FIG. 21, FIG. 21 is essentially similar to FIG. 20. However, in FIG. 21, the groove portion 11E is not formed, and only a pair of non-adhesive portions 11C are formed in the same manner as in FIG. Such a configuration may be used.

Embodiment 2.
<Basic configuration>
FIG. 22 is a schematic plan view showing a mode of the substrate on which the strain detection component of the second embodiment is mounted. With reference to FIG. 22, the configuration of FIG. 22 is basically the same as that of FIG. That is, the strain detection component 21 of the first example of the present embodiment of the present embodiment can be mounted on the printed wiring board 12 as a substrate. Therefore, in FIG. 22, the strain detection component 21 is mounted on the printed wiring board 12. In FIG. 22, the strain detection component 21 is mounted in the region C surrounded by the dotted line.

FIG. 23 is a schematic perspective view of a first example of the region C in which the strain detection component of the first example of the second embodiment, which is surrounded by a dotted line in FIG. 22, is mounted. With reference to FIG. 23, the strain detection component 21 of the first example of the present embodiment has three regions extending substantially along the Z direction and two generally X directions when viewed from the negative side in the Y direction, for example. Includes an area extending along.

The three regions extending approximately along the Z direction are arranged in the leftmost region in the X direction, the rightmost region, and the central region between them. Specifically, the leftmost region and the rightmost region of the three regions extending in the Z direction of the strain detection component 21 are both support portions 21E. Further, among the three regions extending in the Z direction of the strain detection component 21, the portion arranged at the center position in the X direction sandwiched between the two support portions 21E is the crack generation portion 21E2.

The two regions extending approximately along the X direction are arranged in a region between the left support portion 21E and the crack generation portion 21E2 and a region between the crack generation portion 21E2 and the right support portion 21E. .. Specifically, of the two regions extending in the X direction of the strain detection component 21, the region between the left support portion 21E and the crack generating portion 21E2 is the horizontal portion 21DT. Further, of the two regions extending in the X direction of the strain detection component 21, the region between the crack generation portion 21E2 and the right support portion 21E is the horizontal portion 21DB. The strain detection component 21 of FIG. 23 is arranged in the order of the support portion 21E, the horizontal portion 21DT, the crack generation portion 21E2, the horizontal portion 21DB, and the support portion 21E from the left side to the right side in the X direction.

In the distortion detection component 21 of FIG. 23, the uppermost portion of the support portion 21E on the left side and the left end of the horizontal portion 21DT are connected to each other. In the strain detection component 21 of FIG. 23, the right end of the horizontal portion 21DT and the uppermost portion of the crack generation portion 21E2 are connected to each other. In the strain detection component 21 of FIG. 23, the lowermost portion of the crack generation portion 21E2 and the left end of the horizontal portion 21DB are connected to each other. In the strain detection component 21 of FIG. 23, the right end of the horizontal portion 21DB and the lowermost portion of the support portion 21E on the right side are connected. As described above, the strain detection component 21 has four regions in which the portions extending in the Z direction and the portions extending in the X direction are connected. The strain detection component 21 is bent at a substantially right angle in each of these connected regions. As a result, in the strain detection component 21 of FIG. 23, each of the support portion 21E, the horizontal portion 21DT, the crack generation portion 21E2, the horizontal portion 21DB, and the support portion 21E are integrated. The strain detection component 21 has a shape close to an S shape when viewed from the positive side in the Y direction.

The strain detection component 21 formed as an integral body is made of a brittle material such as a conductive resin. More specifically, the strain detection component 21 uses a resin material filled with a conductive filler as the conductive resin. Here, the brittle material means a material that is brittle and fragile as compared with the metal material, as in the first embodiment.

The strain detection component 21 of FIG. 23 includes a first portion and a second portion. The strain detection component 21 includes a first detection unit 21A and a second detection unit 21B as a first portion. The first detection unit 21A is a part of the crack generation unit 21E2. In particular, the first detection unit 21A is the central portion of the crack generation portion 21E2 in the Z direction, and is arranged in a portion not on the extension line of the horizontal portion 21DT and the horizontal portion 21DB. The first detection unit 21A is a portion where cracks are generated due to displacement in the direction along the main surface of the printed wiring board 12 on which the strain detection component 21 is mounted. The direction along the main surface of the printed wiring board 12 is, for example, the direction along the XY plane. The first detection unit 21A is made of a brittle material as described above.

The second detection unit 21B is a part of the horizontal unit 21DT. In particular, the second detection unit 21B is arranged in the leftmost region of FIG. 23 of the horizontal portion 21DT, that is, the region of the horizontal portion 21DT closest to the portion connected to the support portion 21E on the left side of the drawing. The second detection unit 21B is a portion that can be broken due to a crack generated in the first detection unit 21A. That is, if a crack occurs in the first detection unit 21A, the second detection unit 21B connected integrally with the first detection unit 21A may be broken accordingly. That is, in the present embodiment, the second detection unit 21B, which is a portion different from the first detection unit 21A, which is initially caused by the crack of the first detection unit 21A caused by the distortion of the printed wiring board 12. Detects cracks and breakage. Therefore, the second detection unit 21B is made of a brittle material as described above.

From the above, in the strain detection component 21, the pair of support portions 21E are arranged so as to sandwich the first detection unit 21A and the second detection unit 21B in the X direction.

The second portion of the strain detection component 21 is the stress application portion 21C. The stress application portion 21C of the strain detection component 21 of FIG. 23 is formed of, for example, a metal material that generates an attractive force by a magnet. The stress applying portion 21C is, for example, a portion where the horizontal portion 21DT and the crack generating portion 21E2 are connected, and is arranged at a portion where the strain detection component 21 between the two is bent. The metal material of the stress applying portion 21C may be arranged so as to be embedded inside a structure such as a conductive resin constituting the strain detection component 21. As will be described later, the stress applying portion 21C generates an attractive force or a repulsive force by applying a stress such as a magnetic force due to the magnet approaching. As a result, the stress applying unit 21C can apply bending stress, which is a stress, to the second detecting unit 21B of the first portion. This bending stress causes a crack in the second detection unit 21B, and by further extending the crack, the second detection unit 21B can be broken.

In FIG. 23, a pair of copper foil pads 16 are formed as in FIG. 2. The strain detection component 21 is preferably connected on the copper foil pad 16 so as to straddle the pair of copper foil pads 16. Each of the pair of support portions 21E of the strain detection component 21 is connected to each of the pair of copper foil pads 16 by an adhesive 17.

FIG. 24 is a schematic perspective view of a second example of the region C in which the strain detection component of the first example of the second embodiment, which is surrounded by a dotted line in FIG. 22, is mounted. With reference to FIG. 24, FIG. 24 is basically the same as FIG. 23, but like FIG. 3, the copper foil pad 16 is not formed on the printed wiring board 12. As shown in FIG. 24, the strain detection component 21 may be directly connected to one main surface of the printed wiring board 12 by the adhesive 17.

Due to the distortion of the printed wiring board 12 on which the strain detection component 21 is mounted, a crack is generated in the first detection unit 21A of the strain detection component 21. The crack of the first detection unit 21A is generated by the tensile stress generated in a part of the strain detection component 21 due to the strain of the printed wiring board 12 and the compressive stress generated in the other part of the region. Unlike the first embodiment, the tensile stress and the compressive stress in the strain detection component 21 may or may not exist as residual stress in a state where they are not mounted on the printed wiring board 12.

The breakage conditions of the second detection unit 21B due to the application of magnetic force to the stress application unit 21C when cracks are formed in the first detection unit 21A and the second detection unit 21B are shown by the following parameters. .. 25 is a schematic plan view and a schematic front view showing the design parameters of the strain detection component of FIG. 23. FIG. 25 (A) is a plan view, and FIG. 25 (B) is a front view. Note that the length of each part in the figure does not necessarily indicate the actual dimensional value. This also applies to each of the following figures. With reference to FIG. 25, the depth width of the strain detection component 21 of FIG. 23 in the Y direction is defined as b. Let h be the thickness in the Z direction excluding the crack forming portion after the occurrence of the crack and before the occurrence of the break in the second detection portion 21B of the strain detection component 21 of FIG. 23. Let l be the dimension along the X direction from the point of force applied to the stress applying portion 21C of the strain detecting component 21 of FIG. 23 to the second detecting portion 21B where the defect occurs. Further, let F be an applied force as a stress applied to the stress applying portion 21C by a magnet or the like. Let σ be the material tensile strength of the conductive resin that is the constituent material of the strain detection component 21.

FIG. 26 is a schematic view showing a mode in which a second detection unit of the strain detection component of FIG. 23 in which a crack is generated in the first detection unit is broken by a magnet. With reference to FIGS. 25 and 26, when the magnet 21M is brought into contact with the stress application unit 21C in a state where the first detection unit 21A is cracked, the magnetic force of the magnet 21M exerts the applied force F shown in FIG. Can be added. The applied force F is a condition under which the second detection unit 21B of the strain detecting component 21 is broken by the applied force F of the magnetic force as shown in FIG.

It is represented by. If the first detection unit 21A is not cracked, the second detection unit 21B will not be cracked even if the magnet 21M is brought into contact with the stress application unit 21C, and the second detection unit 21B will break. There is no.

For example, consider a case where a neodymium magnet having a circular bottom surface with a diameter of 3 mm and a cylindrical shape with a height of 1.5 mm is used as the magnet 21M. When an applied force F of 1.67N is applied to the magnet 21M, the second detection unit 21B of the strain detection component 21 can be broken by setting the strain detection component 21 as the design parameter shown in Table 3 below. ..

FIG. 27 is a schematic front view showing an aspect of a substrate on which the strain detection component of the second example of the second embodiment is mounted. With reference to FIG. 27, the strain detection component 21 of the second example of the present embodiment is basically the same as the strain detection component 21 of the first example of the present embodiment of FIGS. 23 to 26. However, in FIG. 27, as the second portion, the spring 21F is attached instead of the stress applying portion 21C such as a metal material. The spring 21F is attached, for example, on the left side surface of FIG. 27 of the crack generating portion 21E2. However, the present invention is not limited to this aspect. The spring 21F may be built in the strain detection component 21. In the spring 21F, an elastic force as a stress is applied to the first portion, particularly the second detection portion 21B. Due to this elastic force, it can be installed at an arbitrary position where the crack generated from the second detection unit 21B can be propagated and broken. The stress that the elastic force gives to the strain detection component 21 is a bending stress, which is applied in the vertical direction in the Z direction in the figure.

The spring 21F generates a crack Cka in the second detection unit 21B by using the energy stored by releasing the energy stored by, for example, contracting as an elastic force, and causes the crack Cka to propagate and break. This is because the elastic force of the spring 21F applies bending stress as stress to the second detection unit 21B. If the first detection unit 21A is not cracked, the second detection unit 21B will not crack or break even if the elastic force (bending stress) of the spring 21F is used. The tension of the spring 21F is adjusted so as to be so.

The front view of the strain detection component 21 of FIG. 27 as viewed from the negative side in the Y direction is roughly the same as the strain detection component 21 of FIG. However, the horizontal portion 21DB extends in the X direction from the region on the left side of the crack generation portion 21E2, passes directly under the crack generation portion 21E2, and reaches the support portion 21E on the right side in the drawing. Therefore, the horizontal portion 21DB is in a mode of intersecting the lower portion of the crack generating portion 21E2 at the central portion in the X direction. In this respect, the horizontal portion 21DB of FIG. 27 is formed so that the strain detection component 21 is bent from the lowermost portion of the crack generating portion 21E2 to the right side with the lowermost portion of the crack generating portion 21E2 as the left end. Is different.

As shown in FIG. 27, the distortion detection component 21 of the second example may have a display unit 21G formed therein. As shown in FIG. 26, the display unit 21G has a part of the strain detection component 21 broken, and after the broken part is removed, the debris part after the removal can be observed by visual inspection, visual inspection, AOI, or the like. Part. By using the display unit 21G, it can be confirmed whether or not the strain detection component 21 is broken by the bending stress applied by, for example, the spring 21F or the magnet 21M. The bending stress that breaks the second detection unit 21B usually breaks the first detection unit 21A as shown in FIG. 26. Therefore, the portion connecting the first detection unit 21A and the second detection unit 21B is destroyed so as to be separated from the other parts. This can be confirmed visually or the like.

As shown in FIG. 27, in the strain detection component 21 of the second example, the conductor film 21H may be formed on a part of the surface thereof. Although not shown, the same applies to the strain detection component 21 of the first example. The support portion 21E and the conductor film 21H are used for confirming continuity in the strain detection system described later.

The strain detection component 21 of FIG. 27 may have different design parameters from the strain detection component 21 of FIG. FIG. 28 is a schematic plan view and a schematic front view showing the design parameters of the strain detection component of FIG. 27. (A) of FIG. 28 is a plan view, and (B) of FIG. 28 is a front view. With reference to FIG. 28, let B be the depth width of the strain detection component 21 of FIG. 27 in the Y direction. Let H be the thickness of the crack generating portion 21E2 of the strain detecting component 21 of FIG. 27 along the X direction. Let L be the height of the uppermost surface of the horizontal portion 21DB of the strain detection component 21 of FIG. 27 and the lowermost surface of the horizontal portion 21DT in the Z direction. Let A be the distance along the X direction between the pair of support portions 21E of the strain detection component 21 of FIG. 27. Here, A is the distance between the central portions of the pair of support portions 21E in the X direction. Let σ be the material tensile strength of the conductive resin that is the constituent material of the strain detection component 21. Further, let E be the Young's modulus of the conductive resin of the strain detection component 21. Let δ be the strain displacement of the printed wiring board 12. At this time, the conditions for the strain detection component 21 to cause a crack in the first detection unit 21A are

It is represented by. For example, when a distortion of 500 μST or more occurs in the printed wiring board 12, the design parameters of each part of the distortion detection component 21 for detecting the distortion are as shown in Table 4 below.

From Tables 3 and 4 above, the following can be said in each of the examples of FIGS. 23 and 27 of the present embodiment. In the first portion, the thickness of at least one of the first detection unit 21A and the second detection unit 21B is preferably 1 mm or less. For example, it is preferable that the thickness h shown in Table 2 and the thickness H shown in Table 3 are both 1 mm or less. In this way, it can be said that each portion is sufficiently thin to be easily cracked.

FIG. 29 is a schematic plan view and a schematic front view showing a modified example of the strain detection component of FIG. 23. FIG. 30 is a schematic plan view and a schematic front view showing a modified example of the strain detection component of FIG. 27. 29 and 30 (A) are plan views, and FIGS. 29 and 30 (B) are front views. With reference to FIGS. 29 and 30, these are essentially similar to FIGS. 23 and 27. However, in FIGS. 29 and 30, the pair of support portions 21E constituting the strain detection component 21 are arranged separately from the other portions constituting the strain detection component 21. The pair of support portions 21E is coated on the plating film 21I. In these respects, the strain detection component 21 of FIGS. 29 and 30 is structurally different from the strain detection component 21 of FIGS. 23 and 27. This is because the strain detection components 21 of FIGS. 23 and 27 are all integrated including the pair of support portions 21E, and no plating film is formed on the surface of the support portions 21E.

As shown in FIGS. 23 and 24, the support portion 21E is connected to the printed wiring board 12 or the copper foil pad 16 on the printed wiring board 12 with an adhesive 17. When the adhesive 17 is a material other than solder, no plating film is required on the surface of the support portion 21E. However, when the adhesive 17 is solder, the surface of the support portion 21E needs to be covered with the plating film 21I in advance. In this case, it is preferable that only the support portion 21E is formed as a separate member, and the surface thereof coated with the plating film 21I is joined to each of the other members constituting the strain detection component 21.

<Distortion detection method>
Next, a method of detecting distortion of the printed wiring board 12 by the distortion detecting component of the second embodiment will be described.

The strain detection method of the present embodiment can be described by FIG. 5 basically as in the first embodiment. With reference to FIG. 5 again, first, for example, the strain detection component 21 is mounted on the printed wiring board 12 of FIG. 22 (S10). The configuration of the strain detection component 21 is as described above, and any strain detection component 21 having the aspect of FIGS. 23, 27, 29 or 30 is mounted. Other components other than the distortion detection component 21 are also mounted on the printed wiring board 12 (S20). After all of them are mounted, the presence or absence of cracks in the strain detection component, for example, which occurred during the step (S20) is detected (S30).

The stress application unit 21C or the spring 21F as the second portion applies stress such as bending stress to at least one of the first detection unit 21A and the second detection unit 21B as the first portion. As a result, when the first detection unit 21A is cracked due to the distortion of the printed wiring board 12, the second detection unit 21B is cracked, for example, Z which is the surface side of the first portion. Proceed upward in the direction. As a result, the second detection unit 21B breaks. At this time, the first detection unit 21A may also be broken to divide the strain detection component 21.

Also in the present embodiment, as in the first embodiment, in the step (S30), the presence or absence of cracks in the first detection unit 21A and the second detection unit 21B of the first portion is detected as distortion. It can be detected by visually recognizing whether or not the first portion of the component 21 is broken (S31A). However, in the present embodiment, a method (S31B) of confirming the presence or absence of cracks from the conduction state of the circuit by using the distortion detection system may be used. Hereinafter, the strain detection system of the present embodiment and the strain detection method using the strain detection system will be described with reference to FIG. 31.

<Distortion detection system and distortion detection method using it>
FIG. 31 is a schematic view showing the configuration of the strain detection system of the second embodiment. With reference to FIG. 31, the strain detection system 22 of the present embodiment includes a plurality of strain detection components 21 and a detection circuit 24. As the plurality of strain detection components 21, any one of the above-described embodiments according to the present embodiment is mounted on the main surface of the printed wiring board 12 at intervals from each other. Among the plurality of strain detection components 21, those adjacent to each other are conducted by a generally known wiring 23. That is, a plurality of strain detection components 21 are connected in series to each other by the wiring 23 on the printed wiring board 12. As a result, a wiring circuit is formed by the wiring 23. The plurality of distortion detection components 21 are electrically connected to the detection circuit 24 via a circuit composed of a plurality of wirings 23. Each of the plurality of strain detection components 21 has any of the configurations shown in FIGS. 23, 27, 29, and 30 described above.

In FIG. 31, the strain detection component 21 on the printed wiring board 12 has a direction along the diagonal line, which is the maximum dimension of the strain detection component 21, along the long side direction of the main surface of the printed wiring board 12, which has a low substrate bending resistance. As such, it is more preferred to be implemented. This is the same as FIG. 8 of the first embodiment, for example.

The detection circuit 24 mainly includes a latch circuit 25, a NOR circuit 26, and a light emitting diode 27. The latch circuit 25 is a generally known flip-flop circuit including a NOR circuit 26.

First, a case where all the circuits of the wiring 23 connecting the plurality of distortion detection components 21 on the printed wiring board 12 are energized will be described. The printed wiring board 12 is connected to the set input S of the latch circuit 25, and the reset is ON. In this case, since the potential difference of the reset input R is HIGH and the potential difference of the set input S is LOW, the potential difference of the output from the latch circuit 25 becomes LOW according to the truth table of the flip-flop circuit, and the light emitting diode 27 lights up. If the reset is turned off in this state, the potential difference of the reset input R becomes LOW, and the potential difference of the set input S becomes LOW. Therefore, according to the truth table of the flip-flop circuit, the output from the latch circuit 25 is kept in the previous state, and the light emitting diode 27 is continuously lit.

Next, a case where distortion occurs in the printed wiring board 12 and at least one of the plurality of distortion detection components 21 is disconnected will be described. Specifically, the first portion is between one of the pair of support portions 21E constituting the strain detection component 21 and the other support portion 21E different from the support portion 21E. The conduction state changes due to breakage of at least one of the detection unit 21A and the second detection unit 21B. The change in the conduction state may mean that, for example, due to the above-mentioned breakage, the current flowing between the one support portion 21E and the other support portion 21E does not flow. By detecting this current interruption, it is possible to confirm the occurrence of distortion in the first portion. Alternatively, the change in the conduction state means that, for example, when both the first detection unit 21A and the second detection unit 21B are broken, one support portion 21E and the other support portion 21E become conductive. It may be a configuration. By detecting this continuity, it is possible to confirm the occurrence of distortion in the first portion of any one of the plurality of strain detection components 21.

At this time, when the reset is OFF, the potential difference of the reset input R becomes LOW, and the potential difference of the set input S becomes HIGH. Therefore, according to the truth table of the flip-flop circuit, the potential difference of the output from the latch circuit 25 becomes HIGH, and the light emitting diode 27 is turned off. When the distortion of the printed wiring board 12 is eliminated and the circuit of the wiring 23 connecting the distortion detection components 21 is energized again, the potential difference of the reset input R becomes LOW and the potential difference of the set input S becomes LOW while the reset is OFF. .. Therefore, according to the truth table of the flip-flop circuit, the output from the latch circuit 25 is kept in the previous state, and the light emitting diode 27 is continuously turned off.

As described above, the light emitting diode 27 continues to light unless the printed wiring board 12 is distorted by a reference value or more. However, once the printed wiring board 12 is distorted, the light emitting diode 27 is turned off, and even if it is eliminated, the light emitting diode 27 continues to be turned off. That is, the distortion detection system 22 notifies that a crack has occurred in any of the distortion detection components 21 by changing the lighting state of the light emitting diode 27 by the latch circuit 25. It is possible to highly reliably verify whether or not the distortion of the printed wiring board 12 is large even for a moment due to the change in the conduction state, and whether or not the first portion of any of the plurality of distortion detection components 21 is broken. Further, as described above, the pair of support portions 21E constituting the strain detection component 21 confirm the conduction state between them. As a result, the strain detection system 22 has a role of detecting the presence or absence of cracks in any of the plurality of strain detection components 21.

The present embodiment is different from the first embodiment with respect to each of the above points, but the other points are basically the same as those of the first embodiment. Therefore, the same components are designated by the same reference numerals, and the description will not be repeated in the second embodiment unless there is a particular need.

<Effect>
Next, the action and effect of the present embodiment will be described. In this embodiment, in addition to the same effects as those in the first embodiment, the following effects are exhibited.

The strain detection component 21 according to the disclosure of the present embodiment can be mounted on the printed wiring board 12 as a substrate. The strain detecting component 21 includes a first portion made of a brittle material and a second portion capable of applying, for example, tensile stress as a stress to the first portion. By applying stress to the first portion by the second portion, it is possible to develop cracks generated from the first portion. The first portion is integrated with the first detection unit 21A and the first detection unit 21A, which cause cracks due to displacement in the direction along the main surface of the printed wiring board 12, and the cracks in the first detection unit 21A. Includes a second detection unit 21B that can be broken due to the above. The stress application unit 21C or the spring 21F as the second portion can break the second detection unit 21B of the first portion by applying the stress.

If the first detection unit 21A cracks, the stress application unit 21C or the spring 21F, which is the second portion, applies bending stress to break the second detection unit 21B. Therefore, by using the magnet 21M or the spring 21F that is brought close to the stress applying portion 21C, the strain detecting component 21 made of a brittle material can be easily damaged even in the present embodiment by a slight strain. Therefore, according to the present embodiment, when the distortion of the printed wiring board 12 is large even for a moment, the influence on the electronic components 14 mounted on the printed wiring board 12 and the like can be verified with higher reliability.

Further, in the present embodiment, the strain detection component 21 is broken, but the breakage is easier to see than a simple crack. In particular, if the first detection unit 21A is also broken and the portion sandwiched between the two fractured portions of the strain detection component 21 is disassembled from the other portion, it becomes very easy to visually recognize. Therefore, according to the present embodiment, it is possible to confirm the occurrence of distortion on the printed wiring board 12 more easily than in the first embodiment.

If the spring 21F is used as the second portion, the step of bringing the magnet 21M closer to the stress applying portion 21C becomes unnecessary. Therefore, the procedure of distortion detection can be further simplified.

The strain detection system 22 according to the present disclosure includes a plurality of strain detection components 21 mounted on a printed wiring board 12 as a substrate at intervals, and detection that is electrically connected to the plurality of strain detection components 21. It includes a circuit 24. Each of the plurality of strain detecting components 21 includes a first portion made of a brittle material and a second portion capable of applying, for example, tensile stress as a stress to the first portion. The first portion is integrated with the first detection unit 21A and the first detection unit 21A, which cause cracks due to displacement in the direction along the main surface of the printed wiring board 12, and the cracks in the first detection unit 21A. It has a second detection unit 21B that can be broken due to the above. The stress application unit 21C or the spring 21F as the second portion can break the second detection unit 21B of the first portion by applying the stress. The strain detection component 21 further includes a pair of support portions 21E arranged so as to sandwich the first detection unit 21A and the second detection unit 21B.

As described above, by using the magnet 21M or the spring 21F that approaches the stress application portion 21C, the strain detection component 21 made of a brittle material can be easily damaged by a slight strain. If the detection circuit 24 is used, it detects disconnection or the like. As a result, even if the fracture surfaces of the cracks come into contact with each other again when the distortion is eliminated because the cracks of the distortion detection component 21 caused by the distortion of the printed wiring board 12 are minute, the detection circuit 24 At least the moment when distortion occurs can be detected. Therefore, the occurrence of distortion exceeding the reference value on the printed wiring board 12 is not overlooked. Therefore, according to the present embodiment, when the distortion of the printed wiring board 12 is large even for a moment, the influence on the electronic components 14 mounted on the printed wiring board 12 and the like can be verified with higher reliability.

In the distortion detection system 22, one support portion 21E of the pair of support portions and the other support portion 21E different from the one support portion 21E are the first detection portions 21A. And when at least one of the second detection units 21B is broken, the conduction state changes, so that the occurrence of distortion in the first portion can be confirmed. Such a configuration is preferable.

At least when strain occurs, the conduction state between the pair of support portions 21E changes. By detecting the change in the conduction state, the detection circuit 24 of the strain detection system 22 can detect at least the moment of the change. Therefore, even if the cracks come into contact with each other again and the cracks do not occur, the occurrence of the cracks can be reliably detected.

In the distortion detection method according to the disclosure of the present embodiment, a step of mounting the distortion detection component 21 on the printed wiring board 12 as a substrate is performed. Another component mounting process is performed in which components other than the strain detection component 21 are mounted on the printed wiring board 12. A step of detecting the presence or absence of cracks in the strain detection component 21 is performed. The strain detecting component 21 includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion. When the second portion applies stress such as tensile stress to the first portion and the strain generated in the printed wiring board 12 causes a crack in the first portion, a crack is generated on the surface side of the first portion. Make progress. The first portion is integrated with the first detection unit 21A and the first detection unit 21A, which cause cracks due to displacement in the direction along the main surface of the printed wiring board 12, and the cracks in the first detection unit 21A. Includes a second detection unit 21B that can be broken due to the above. The strain detection component 21 further includes a pair of support portions 21E arranged so as to sandwich the first detection unit 21A and the second detection unit 21B. In the above-mentioned detection step, one support portion 21E of the pair of support portions 21E and the other support portion 21E different from one support portion 21E are in a conductive state when the first portion is broken. It is possible to confirm the occurrence of distortion in the first portion by changing.

According to the above strain detection method, the conduction state between the pair of support portions 21E changes at least when a crack occurs due to strain. By detecting the change in the conduction state, at least the moment of the change can be detected by the detection circuit 24 of the strain detection system 22 that detects the strain by, for example, the strain detection method. Therefore, even if the cracks come into contact with each other again and the cracks do not occur, the occurrence of the cracks can be reliably detected.

Summarizing the above, in the present embodiment, even when a crack occurs in the first detection unit 21A or the like of the first portion of the distortion detection component 21 due to a slight distortion of the printed wiring board 12, the second portion By applying a bending stress, which is a stress, to the second detection unit 21B, a crack can be generated in the second detection unit 21B caused by the crack, and the crack can be propagated and broken, for example. Therefore, a slight distortion of the printed wiring board 12 can be detected with high accuracy. However, in the present embodiment, if a slight crack is momentarily generated in the distortion detection component 21 due to the distortion of the printed wiring board 12, the distortion detection system 22 can reliably detect it. That is, in the present embodiment, both the crack confirmation method by visual inspection and the confirmation method using the strain detection system 22 can be applied.

Embodiment 3.
<Basic configuration>
FIG. 32 is a schematic plan view showing an aspect of the substrate on which the strain detection component of the third embodiment is mounted. With reference to FIG. 32, the configuration of FIG. 32 is basically the same as that of FIG. That is, the strain detection component 31 of the present embodiment of the present embodiment can be mounted on the printed wiring board 12 as a substrate. Therefore, in FIG. 32, the distortion detection component 31 is mounted on the printed wiring board 12. In FIG. 32, the strain detection component 31 is mounted in the area D surrounded by the dotted line.

FIG. 33 is a schematic perspective view of a region D in which the strain detection component surrounded by the dotted line in FIG. 32 is mounted. FIG. 34 is a schematic perspective view showing each component of the strain detection component in an exploded manner in order to show the configuration of the strain detection component of the third embodiment in FIG. 33. That is, (A) of FIG. 34 shows each member in an exploded manner, and (B) of FIG. 34 shows an appearance mode of the strain detection component 31 in which each member shown in FIG. 34 (A) is assembled. With reference to FIGS. 33 and 34, the strain detection component 31 includes a laminated portion 31A, a pair of conductive wiring layers 31B, and a pair of electrodes 31C. In the laminated portion 31A, the dielectric material layer 31d and the conductive material layer 31e are alternately laminated. Both the dielectric material layer 31d and the conductive material layer 31e are sheet-shaped, that is, for example, rectangular members. The number of these layers is arbitrary, but in FIG. 34, for example, two layers are laminated in the Z direction.

The conductive wiring layer 31B is a member capable of sandwiching the entire laminated portion 31A in which a plurality of dielectric material layers 31d and a conductive material layer 31e are laminated in the Z direction from the upper side and the lower side in the Z direction. The conductive wiring layer 31B is formed of, for example, a conductive resin. A pair of conductive wiring layers 31B are arranged. As shown in FIG. 34, of the pair of conductive wiring layers 31B on the upper side in the Z direction, three portions extending in the X direction are spaced apart in the Y direction, and three portions extending in the Y direction are oriented in the X direction. Two are included at intervals. These are extended so as to be one. That is, the conductive wiring layer 31B is bent by about 90 ° at the boundary between the portion extending in the X direction and the portion extending in the Y direction. The conductive wiring layer 31B on the upper side in the Z direction is connected to the portion extending in the Y direction at the right end portion of the portion extending in the X direction on the most positive side in the Y direction. The end of the portion extending in the Y direction on the negative side in the Y direction is connected to the portion extending in the X direction. The end of the portion extending in the X direction on the negative side in the X direction is connected to the portion extending in the Y direction. The end of the portion extending in the Y direction on the negative side in the Y direction is connected to the portion extending in the X direction. A terminal 31D connected to the right electrode 31C of the pair is provided at the end of the portion extending in the X direction on the positive side in the X direction. As described above, the conductive wiring layer 31B has a substantially S-shape.

As shown in FIG. 34, of the pair of conductive wiring layers 31B on the lower side in the Z direction, two portions extending in the X direction are spaced apart in the Y direction and one portion extending in the Y direction. ,include. These are extended so as to be one. That is, the conductive wiring layer 31B is bent by about 90 ° at the boundary between the portion extending in the X direction and the portion extending in the Y direction. The conductive wiring layer 31B on the lower side in the Z direction is connected to the portion extending in the Y direction at the right end portion of the portion extending in the X direction on the positive side in the Y direction. The end of the portion extending in the Y direction on the negative side in the Y direction is connected to the portion extending in the X direction. A terminal 31D connected to the left electrode 31C of the pair is provided at the end of the portion extending in the X direction on the positive side in the X direction. As described above, the conductive wiring layer 31B has a substantially U-shape.

The pair of electrodes 31C sandwiches the laminated portion 31A and the pair of conductive wiring layers 31B above and below the laminated portion 31A from, for example, the X direction where the pair of conductive wiring layers 31B intersect the laminated portion 31A in the Z direction. It is arranged like this. One of the pair of electrodes 31C, for example the left electrode 31C, contacts the terminal 31D formed on, for example, the upper conductive wiring layer 31B. As a result, the left electrode 31C is connected to the upper conductive wiring layer 31B. The other of the pair of electrodes 31C, which is different from the above one, for example, the right electrode 31C, contacts the other, for example, the terminal 31D formed on the lower conductive wiring layer 31B. As a result, the electrode 31C on the right side is connected to the conductive wiring layer 31B on the lower side. As described above, the pair of electrodes 31C has a voltage between one of the pair of conductive wiring layers 31B, the conductive wiring layer 31B, and the other conductive wiring layer 31B, which is different from the one conductive wiring layer 31B. Can be applied.

Regarding the extending direction of the upper conductive wiring layer 31B, a hole 31h penetrating the terminal 31D in the thickness direction is formed at the end portion on the opposite side to the side where the terminal 31D is provided. Similarly, in the extending direction of the lower conductive wiring layer 31B, a hole 31h is also formed at an end portion on the side opposite to the side where the terminal 31D is provided. Further, holes 31h are similarly formed in each of the dielectric material layer 31d and the conductive material layer 31e of the laminated portion 31A. Each of these holes 31h is formed at a position where each layer of the laminated portion 31A and a pair of conductive wiring layers 31B overlap each other in a plan view when they are laminated. When these are laminated, the conductor is filled in each hole 31h. By this conductor, the upper conductive wiring layer 31B, each layer of the laminated portion 31A, and the lower conductive wiring layer 31B are electrically conductive with each other.

<Distortion detection system and distortion detection method using it>
FIG. 35 is a schematic view showing the configuration of the strain detection system of the third embodiment. With reference to FIG. 35, in the strain detection system 32 of the present embodiment, the plurality of strain detection components 21 in the strain detection system 22 of FIG. 31 are replaced with a plurality of strain detection components 31. Since the other points of the strain detection system 32 are the same as those of the strain detection system 22, the description thereof will not be repeated.

The strain detection method of the present embodiment using the strain detection system 32 is basically the same as the strain detection method using the strain detection system 22 of the second embodiment. That is, as in the second embodiment, the presence or absence of cracks in at least one of the plurality of strain detection components 32 is detected. At this time, as in the second embodiment, the disconnection of the circuit connecting the strain detection component 32 due to the occurrence of a crack in at least one of the plurality of strain detection components 32 is electrically connected to the plurality of strain detection components 32. It is detected by the detection circuit 24. Specifically, the disconnection is detected by a change in the lighting state of the light emitting diode 27 included in the detection circuit 24 of FIG. 35.

The present embodiment is different from the second embodiment with respect to each of the above points, but the other points are basically the same as those of the second embodiment. Therefore, the same components are designated by the same reference numerals, and the description will not be repeated in the second embodiment unless there is a particular need.

<Effect>
Next, the action and effect of the present embodiment will be described.

The strain detection component 31 according to the disclosure of the present embodiment is a strain detection component mounted on a substrate. The strain detection component 31 includes a laminated portion 31A, a conductive wiring layer 31B, and a pair of electrodes 31C. In the laminated portion 31A, the dielectric material layer 31d and the conductive material layer 31e are alternately laminated. The conductive wiring layers 31B are arranged in pairs so as to sandwich the laminated portion 31A in the Z direction in which the laminated portions 31A are laminated, for example. The pair of electrodes 31C can apply a voltage between one of the pair of conductive wiring layers 31B, the conductive wiring layer 31B, and the other conductive wiring layer 31B, which is different from the one conductive wiring layer 31B. Is. The pair of electrodes 31C sandwiches the laminated portion 31A and the pair of conductive wiring layers 31B from, for example, the X direction, which is the direction in which the pair of conductive wiring layers 31B sandwich the laminated portion 31A, for example, in the Z direction. Is placed in. One of the pair of electrodes 31C, 31C, is connected to one conductive wiring layer 31B. Of the pair of electrodes 31C, the other electrode 31C, which is different from one electrode 31C, is connected to the other conductive wiring layer 31B.

The strain detection component 31 may be configured as in the present embodiment. In this way, the number and material of the dielectric material layer 31d and the conductive material layer 31e of the laminated portion 31A, the distance between the dielectric material layer 31d and the conductive material layer 31e in the Z direction, and the X and Y of the entire strain detection component 31 By controlling the dimensions in the Z direction, the crack resistance of the strain detection component 31 can be controlled. For example, the dimensions of the entire strain detection component 31 in the X, Y, and Z directions may be the same as those of the multilayer ceramic capacitor as the electronic component 14 mounted on the printed wiring board 12. If the dimensions are controlled as described above, the fragility of the strain detection component 31 can be made equal to the fragility of the multilayer ceramic capacitor as the electronic component 14. Thereby, the fragility of the multilayer ceramic capacitor as the electronic component 14 can be verified.

The strain detection system 32 according to the disclosure of the present embodiment electrically includes a plurality of strain detection components 31 mounted on the printed wiring board 12 as a substrate at intervals, and the plurality of strain detection components 31. It includes a detection circuit 24 to be connected. Each of the plurality of strain detection components 21 includes a laminated portion 31A, a conductive wiring layer 31B, and a pair of electrodes 31C. In the laminated portion 31A, the dielectric material layer 31d and the conductive material layer 31e are alternately laminated. The conductive wiring layers 31B are arranged in pairs so as to sandwich the laminated portion 31A in the Z direction in which the laminated portions 31A are laminated, for example. The pair of electrodes 31C can apply a voltage between one of the pair of conductive wiring layers 31B, the conductive wiring layer 31B, and the other conductive wiring layer 31B, which is different from the one conductive wiring layer 31B. Is. The pair of electrodes 31C sandwiches the laminated portion 31A and the pair of conductive wiring layers 31B from, for example, the X direction, which is the direction in which the pair of conductive wiring layers 31B sandwich the laminated portion 31A, for example, in the Z direction. Is placed in. One of the pair of electrodes 31C, 31C, is connected to one conductive wiring layer 31B. Of the pair of electrodes 31C, the other electrode 31C, which is different from one electrode 31C, is connected to the other conductive wiring layer 31B.

If the detection circuit 24 is used, it detects disconnection or the like. As a result, even if the fractured surfaces of the cracks come into contact with each other again when the distortion is eliminated because the crack of the distortion detection component 31 caused by the distortion of the printed wiring board 12 is minute, the detection circuit 24 can be used. At least the moment when distortion occurs can be detected. Therefore, the occurrence of distortion exceeding the reference value on the printed wiring board 12 is not overlooked. Therefore, according to the present embodiment, when the distortion of the printed wiring board 12 is large even for a moment, the influence on the electronic components 14 mounted on the printed wiring board 12 and the like can be verified with higher reliability.

In the distortion detection method according to the disclosure of the present embodiment, a step of mounting a plurality of distortion detection components 31 on the printed wiring board 12 as a substrate is performed. Another component mounting process is performed in which components other than the plurality of distortion detection components 31 are mounted on the printed wiring board 12. A step of detecting the presence or absence of cracks in at least one of the plurality of strain detection components 31 is performed. Each of the plurality of strain detection components 31 mounted on the main surface of the printed wiring board 12 includes a laminated portion 31A, a conductive wiring layer 31B, and a pair of electrodes 31C. In the laminated portion 31A, the dielectric material layer 31d and the conductive material layer 31e are alternately laminated. The conductive wiring layers 31B are arranged in pairs so as to sandwich the laminated portion 31A in the Z direction in which the laminated portions 31A are laminated, for example. The pair of electrodes 31C can apply a voltage between one of the pair of conductive wiring layers 31B, the conductive wiring layer 31B, and the other conductive wiring layer 31B, which is different from the one conductive wiring layer 31B. Is. The pair of electrodes 31C sandwiches the laminated portion 31A and the pair of conductive wiring layers 31B from, for example, the X direction, which is the direction in which the pair of conductive wiring layers 31B sandwich the laminated portion 31A, for example, in the Z direction. Is placed in. One of the pair of electrodes 31C, 31C, is connected to one conductive wiring layer 31B. Of the pair of electrodes 31C, the other electrode 31C, which is different from one electrode 31C, is connected to the other conductive wiring layer 31B. In the detection process, the disconnection of the circuit connecting the strain detection component 31 due to the occurrence of a crack in at least one of the plurality of strain detection components 31 is electrically connected to the plurality of strain detection components 31. Is detected by.

According to the above distortion detection method, the circuit connecting the strain detection component 31 is disconnected when at least one of the strain detection components 31 is cracked due to the strain. By detecting this disconnection, at least the moment of the change can be detected by the detection circuit 24 of the strain detection system 22 that detects the strain by, for example, the strain detection method. Therefore, even if the cracks come into contact with each other again and the cracks do not occur, the occurrence of the cracks can be reliably detected.

Summarizing the above, in the present embodiment, if a crack is instantaneously generated in the distortion detection component 21 due to the distortion of the printed wiring board 12, the distortion detection system 32 can reliably detect it. That is, in the present embodiment, the confirmation method using the distortion detection system 32 can be applied.

The features described in each of the above-described embodiments (each example included in the above) may be applied so as to be appropriately combined within a technically consistent range.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

11,21,31 Strain detection component, 11A 1st member, 11B 2nd member, 11C non-adhesive part, 11D paint coating surface, 11E groove part, 12 printed wiring board, 12a connector peripheral part, 12b board corner part, 12c component peripheral part Parts, 13 connectors, 14 electronic components, 16 copper foil pads, 17 adhesives, 21A first detection part, 21B second detection part, 21C stress application part, 21DB, 21DT horizontal part, 21E support part, 21E2 crack generation Part, 21F spring, 21G display part, 21H conductor film, 21I plating film, 21M magnet, 22 distortion detection system, 23 wiring, 24 detection circuit, 25 latch circuit, 26 NOR circuit, 27 light emitting diode, 31A laminated part, 31B conductivity Sexual wiring layer, 31C electrode, 31D terminal, 31d dielectric material layer, 31e conductive material layer.

Claims (15)

It is a distortion detection component that can be mounted on a board.
The first part made of brittle material and
A second portion capable of applying stress to the first portion is provided.
A strain detection component capable of advancing cracks generated from the first portion by applying stress to the first portion by the second portion. The brittle material is either glass or ceramic and
The second portion is made of a material having a tensile strength equal to or higher than that of the brittle material.
In the region inside the adhesive portion between the first portion and the second portion in at least one direction in a plan view, a non-adhesive portion in which the first portion and the second portion are not adhered is formed. The strain detection component according to claim 1, which is formed. In the first portion, tensile stress is generated in a state where it is not mounted on the substrate.
The strain detection component according to claim 1 or 2, wherein compressive stress is generated in the second portion without being mounted on the substrate. Claim 1 in which at least one of the first portion and the second portion is formed with a defect portion in which at least one of the first portion and the second portion is partially missing. The distortion detection component according to any one of 3 to 3. The first portion is integrated with a first detection unit that causes a crack due to displacement in a direction along the main surface of the substrate and the first detection unit, and is caused by a crack in the first detection unit. Including a second detection unit that can be broken
The strain detection component according to claim 1, wherein the second portion can break the second detection portion of the first portion by applying the stress. The strain detection component according to claim 5, wherein the first portion has a thickness of at least one of the first detection unit and the second detection unit of 1 mm or less. Multiple strain detection components mounted on the board at intervals,
A detection circuit that is electrically connected to the plurality of distortion detection components is provided.
Each of the plurality of strain detection components includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion.
The first portion is integrated with a first detection unit that causes a crack due to displacement in a direction along the main surface of the substrate and the first detection unit, and is caused by a crack in the first detection unit. It has a second detection unit that can be broken.
The second portion can break the second detection portion of the first portion by applying the stress.
The distortion detection system further includes a pair of support portions arranged so as to sandwich the first detection unit and the second detection unit. One of the support portions of the pair of support portions and the other support portion different from the one support portion are said to have the first support portion due to a change in the conduction state when the first portion is broken. The distortion detection system according to claim 7, wherein it is possible to confirm the occurrence of distortion in a portion. The process of mounting strain detection components on the board,
Other component mounting process for mounting components other than the strain detection component on the board, and
It is provided with a process of detecting the presence or absence of cracks in the strain detection component.
The strain detection component includes a first portion made of a brittle material and a second portion capable of applying stress to the first portion.
When the second portion applies stress to the first portion and a crack is generated in the first portion due to the strain generated in the substrate, the crack propagates to the surface side of the first portion. Distortion detection method. Prior to the mounting step, a tensile stress is applied to the first portion, and the first portion and the second portion are adhered to each other in a state where a compressive stress is applied to the second portion. , The distortion detection method according to claim 9. The strain detection method according to claim 9 or 10, wherein in the detection step, the presence or absence of cracks in the first portion is detected by visually recognizing the first portion. The first portion is integrated with a first detection unit that causes a crack due to displacement in a direction along the main surface of the substrate and the first detection unit, and is caused by a crack in the first detection unit. It has a second detection unit that can be broken.
The strain detection component further includes a pair of support portions arranged so as to sandwich the first detection unit and the second detection unit.
In the detection step, a conductive state is established between one of the pair of support portions and the other support portion different from the one support portion when the first portion is broken. The distortion detection method according to any one of claims 9 to 11, wherein it is possible to confirm the occurrence of distortion in the first portion by changing. It is a distortion detection component mounted on the board.
A laminated portion in which dielectric material layers and conductive material layers are alternately laminated, and
A pair of conductive wiring layers arranged so as to sandwich the laminated portion in the direction in which the laminated portions are laminated.
A pair of electrodes capable of applying a voltage between one of the pair of conductive wiring layers and the other conductive wiring layer different from the one conductive wiring layer is provided.
The pair of electrodes are arranged so as to sandwich the laminated portion and the pair of conductive wiring layers from the direction in which the pair of conductive wiring layers intersect in the direction of sandwiching the laminated portion.
One of the pair of electrodes is connected to the one conductive wiring layer.
A strain detection component in which the other electrode of the pair of electrodes, which is different from the one electrode, is connected to the other conductive wiring layer. Multiple strain detection components mounted on the board at intervals,
A detection circuit that is electrically connected to the plurality of distortion detection components is provided.
Each of the plurality of strain detection components is arranged in pairs so as to sandwich the laminated portion in which the dielectric material layer and the conductive material layer are alternately laminated and the laminated portion in the direction in which the laminated portion is laminated. A pair of conductive wiring layers to which a voltage can be applied between the conductive wiring layer, one of the pair of conductive wiring layers, and the other conductive wiring layer different from the one conductive wiring layer. Equipped with electrodes
The pair of electrodes are arranged so as to sandwich the laminated portion and the pair of conductive wiring layers from the direction in which the pair of conductive wiring layers intersect in the direction of sandwiching the laminated portion.
One of the pair of electrodes is connected to the one conductive wiring layer.
A strain detection system in which the other electrode of the pair of electrodes, which is different from the one electrode, is connected to the other conductive wiring layer. The process of mounting multiple strain detection components on the board,
The other component mounting process for mounting components other than the plurality of strain detection components on the substrate, and
A step of detecting the presence or absence of cracks in at least one of the plurality of strain detection components is provided.
Each of the plurality of strain detection components mounted on the main surface of the substrate has a laminated portion in which dielectric material layers and conductive material layers are alternately laminated, and the laminated portion in a direction in which the laminated portions are laminated. A pair of conductive wiring layers arranged so as to sandwich the two, one of the pair of conductive wiring layers, and the other conductive wiring layer different from the one conductive wiring layer. It is equipped with a pair of electrodes to which a voltage can be applied between them.
The pair of electrodes are arranged so as to sandwich the laminated portion and the pair of conductive wiring layers from the direction in which the pair of conductive wiring layers intersect in the direction of sandwiching the laminated portion.
One of the pair of electrodes is connected to the one conductive wiring layer.
The other electrode of the pair of electrodes, which is different from the one electrode, is connected to the other conductive wiring layer.
In the detection step, a detection circuit that electrically connects the disconnection of the circuit connecting the strain detection components due to cracking in at least one of the plurality of strain detection components to the plurality of strain detection components. Distortion detection method to detect by.

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