Substrate unit

Abstract

To simplify the constitution of a substrate, to improve workability at the time of soldering and to suppress the generation of solder cracks in a structure for assembling two substrates and connecting the substrates by soldering.SOLUTION: The substrate unit 1 includes a main substrate 10 and a sub-substrate 20 orthogonal to the main substrate 10. A first insertion part 21 provided on a sub board 20 is inserted into a slit 11 provided on a main board 10. The sub board 20 is provided with a cutout portion 23 cut out in the X direction, and the main board 10 is provided with a second insertion portion to be inserted into the cutout portion 23. At the first position P1 where the positions of the first solder pad 4 and the second solder pad 5 in the X direction are shifted from each other, the second insertion portion is not inserted into the cutout portion 23, and at the second position P2 where the positions of the first solder pad 4 and the second solder pad 5 in the X direction coincide with each other, the second insertion portion is inserted into the cutout portion 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a board unit. [Background technology]

[0002] When there is not enough space in the device to mount a large board, the circuit may be divided into multiple boards and mounted. In such cases, electrical connections between the boards are required. For example, connectors are used to connect the boards.

[0003] Patent Document 1 discloses a structure for connecting two boards without using a connector. In Patent Document 1, a slit-shaped through hole is provided in a first circuit board, and a second circuit board is inserted into the through hole, and the two boards are assembled in a perpendicular state. At this time, the connection between the boards is achieved by positioning and soldering solder pads provided on the edge of the through hole of the first circuit board and solder pads provided on the second circuit board.

[0004] In the board-to-board connection structure of Patent Document 1, solder pads are provided on the edges of the through-holes (slits) into which the second circuit board is inserted, and grooves are provided on the inner surface of the through-hole at the positions of the solder pads. This makes it easier for solder to penetrate between the inner surface of the through-hole and the surface of the second circuit board inserted into the through-hole, increasing the contact area with the solder. This therefore improves the reliability of the solder connection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Utility Model No. 216600231 Summary of the Invention [Problem to be solved by the invention]

[0006] The board-to-board connection structure of Patent Document 1 requires grooves to be formed on the inner surface of the through-holes (slits) into which the boards are inserted, in accordance with the positions of the solder pads. This makes the shape of the slits complex, requiring additional processing steps. While the shape can be simplified by eliminating the grooves, this leaves open the issue of improving the reliability of the solder connections.

[0007] Furthermore, in the board connection structure of Patent Document 1, the second circuit board is oriented perpendicular to the first circuit board, which can cause the second circuit board to tilt and make the second circuit board unstable. This makes soldering difficult to perform. Furthermore, if the second circuit board tilts, cracks can occur in the soldered areas.

[0008] In view of the above problems, an object of the present invention is to simplify the structure of the boards in a structure in which two boards are assembled and connected by soldering, to improve the workability during soldering, and to suppress the occurrence of solder cracks. Another object of the present invention is to improve the reliability of the connection between the boards by soldering. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, one aspect of the substrate unit according to the present invention is a substrate unit having a first substrate and a second substrate perpendicular to the first substrate, wherein a first insertion portion provided on the second substrate is inserted into a slit provided on the first substrate, and a first solder pad provided on an edge of the slit and a second solder pad provided on the first insertion portion are positioned and soldered in the longitudinal direction of the slit, and the slit and the first insertion portion are The portion is shaped so that, when the first insertion portion is inserted into the slit, it can move from a first position where the longitudinal positions of the first solder pad and the second solder pad are misaligned to a second position where the longitudinal positions of the first solder pad and the second solder pad are the same, and one of the first substrate and the second substrate has a notch cut out in the longitudinal direction, and the other of the first substrate and the second substrate has a second insertion portion to be inserted into the notch, and at the first position the second insertion portion is not inserted into the notch, and at the second position the second insertion portion is inserted into the notch. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of the main part of the board unit. [Figure 2] FIG. 2 is a front view of the main part of the board unit. [Figure 3] FIG. 3 is a plan view of the main part of the board unit. [Figure 4] FIG. 4 is a plan view of the Z1-side and Z2-side substrate surfaces of the sub-board. [Figure 5] FIG. 5 is a partial cross-sectional view schematically showing a section taken at the joining position of the first solder pad and the second solder pad (position AA in FIG. 2). [Figure 6] FIG. 6 is a perspective view of the main board and the sub-board before assembly. [Figure 7] FIG. 7 is a perspective view of the main board and the sub-board during assembly. [Figure 8] FIG. 8 is a perspective view showing a main part of the substrate unit of the first modification. [Figure 9] FIG. 9 is a perspective view and a front view showing a main part of a board unit of the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the substrate unit will be described with reference to the drawings. In this specification, the three directions X, Y, and Z are mutually orthogonal. One side of the X direction is designated X1, and the other side of the X direction is designated X2. One side of the Y direction is designated Y1, and the other side of the Y direction is designated Y2. One side of the Z direction is designated Z1, and the other side of the Z direction is designated Z2.

[0012] FIG. 1 is a perspective view of the main parts of the board unit 1. FIG. 2 is a front view of the main parts of the board unit 1. FIG. 3 is a plan view of the main parts of the board unit 1. As shown in FIGS. 1, 2, and 3, the board unit 1 comprises a main board 10 and a sub-board 20 that is perpendicular to the main board 10. The main board 10 is the first board. The sub-board 20 is the second board. The main board 10 is parallel to the XZ plane. The sub-board 20 is parallel to the XY plane.

[0013] The main board 10 is, for example, a control circuit board. The sub-board 20 is, for example, an interface board on which an LED display element 2, a switch element 3, etc. are mounted. The sub-board 20 of this embodiment is a board smaller than the main board 10. The LED display element 2 and the switch element 3 are arranged, for example, at the positions indicated by the dashed lines in FIG. 1. The sub-board 20 controls the display of the LED display element 2 based on a control signal from a control circuit mounted on the main board 10. Furthermore, when the switch element 3 is operated by a user, a detection signal corresponding to the operation of the switch element 3 is supplied from the sub-board 20 to the main board 10.

[0014] As shown in Figure 2, the Z1-direction end of the main substrate 10 is provided with a linear slit 11 extending in the X-direction and a rectangular step 12 cut out in the Z2-direction. The slit 11 and step 12 are aligned in the X-direction. The slit 11 is a through-hole that penetrates the main substrate 10. The longitudinal direction of the slit 11 is the X-direction. The step 12 has a first edge 13 extending in the X-direction and a second edge 14 extending in the Z-direction.

[0015] 1 and 3, the end of the sub-board 20 in the Y1 direction is provided with a first insertion portion 21 that is inserted into the slit 11 of the main board 10, and a protrusion 22 that is placed on the step 12 of the main board 10. The tip of the first insertion portion 21 is inserted into the slit 11 and is positioned on the Y1 side of the main board 10. The tip of the protruding portion 22 protrudes from the step portion 12 toward the Y1 side of the main board 10.

[0016] (solder pad) The main substrate 10 has a plurality of first solder pads 4 provided on the edge of the slit 11. Three first solder pads 4 are provided on the edge of the slit 11 in the Z1 direction, and four first solder pads 4 are provided on the edge of the slit 11 in the Z2 direction. The first solder pads 4 are provided on both the front and back surfaces of the main substrate 10. While FIG. 2 illustrates the first solder pads 4 provided on the substrate surface 10a on the Y1 side of the main substrate 10, first solder pads 4 are also provided on the substrate surface 10b on the Y2 side, at positions behind each of the first solder pads 4 on the substrate surface 10a.

[0017] The sub-substrate 20 has second solder pads 5 provided on the first insertion portion 21. As shown in FIGS. 1, 2, and 3, the second solder pads 5 are provided at positions that coincide with the positions of the multiple first solder pads 4 in the X direction. The first solder pads 4 and second solder pads 5 function as electrodes that are electrically connected to circuits mounted on each substrate. The first solder pads 4 and second solder pads 5 that coincide with each other in the X direction are joined by soldering.

[0018] 4 is a plan view of the Z1-side board surface 20a and the Z2-side board surface 20b of the sub-board 20. As described above, the Y1-direction end of the sub-board 20 has the first insertion portion 21 and protruding portion 22, which protrude in the Y1 direction, lined up in the X2 direction, and a rectangular notch is formed in the Y2 direction between the first insertion portion 21 and the protruding portion 22. The first insertion portion 21 has three second solder pads 5 on the Z1-side board surface 20a and four second solder pads 5 on the Z2-side board surface 20b.

[0019] Furthermore, as shown in FIG. 2, the main substrate 10 includes a plurality of third solder pads 6 arranged along the first edge 13 of the step portion 12. In contrast, as shown in FIG. 4, the sub-substrate 20 includes a plurality of fourth solder pads 7 provided on the substrate surface 20b on the Z2 side of the protrusion 22. Each of the plurality of fourth solder pads is positioned in the X direction to coincide with one of the plurality of third solder pads 6. In this embodiment, the third solder pads 6 and the fourth solder pads 7 are provided in three locations. The third solder pads 6 and the fourth solder pads 7 function as electrodes electrically connected to circuits mounted on each substrate. The third solder pads 6 and the fourth solder pads 7, which are positioned in the X direction, are joined by soldering. Note that the solder added by soldering is not shown in FIGS. 1, 2, and 3.

[0020] 5 is a partial cross-sectional view schematically showing a section taken at the joining position (position AA in FIG. 2) of the first solder pad 4 and the second solder pad 5. As shown in FIG. 4, the second solder pads 5 at six of the seven locations are strip-shaped and long in the Y direction, and the length in the Y direction is greater than the thickness T1 of the main substrate 10. Therefore, as shown in FIGS. 2 and 5, the second solder pads 5 pass through the inside of the slits 11 and extend to the Y1 and Y2 sides of the main substrate 10.

[0021] As shown in Fig. 5, the width W of the slit 11 provided in the main substrate 10 is greater than the maximum thickness T2 of the sub-substrate 20. Here, the maximum thickness T2 is a dimension including the thickness of the second solder pad 5. When assembling the main substrate 10 and the sub-substrate 20, as shown in Fig. 5, the sub-substrate 20 is positioned so that the first insertion portion 21 is disposed in the center of the slit 11 in the Z direction. As a result, a gap S in the Z direction is formed between the second solder pad 5 and the inner surface of the slit 11 on the Z1 side and the Z2 side of the first insertion portion 21, respectively.

[0022] It is preferable that the width W of the slit 11 is larger than the maximum thickness T2 of the sub-substrate 20 by 0.3 mm or more. In this case, the gap S is 0.15 mm or more. In this state, when the first solder pad 4 and the second solder pad 5 are soldered at the point where they intersect, the solder 30 enters the gap S, as shown in Fig. 5. This increases the contact area between the first solder pad 4 and the second solder pad 5 via the solder 30.

[0023] It is preferable that the locations where the third solder pad 6 and the fourth solder pad 7 are soldered have a similar configuration. As shown in Figures 3 and 4, the fourth solder pad 7 is strip-shaped and long in the Y direction, and its length in the Y direction is greater than the thickness T1 of the main substrate 10. Therefore, the fourth solder pad 7 passes through the Z1 side of the step portion 12 and extends to the Y1 and Y2 sides of the main substrate 10.

[0024] When assembling the main board 10 and the sub-board 20, the sub-board 20 is positioned so that a gap of 0.15 mm or more is formed between the fourth solder pad 7 and the Z1-side end face of the first edge 13. In this state, when the third solder pad 6 and the fourth solder pad 7 are soldered at a point where they intersect, the solder 30 enters the gap. This increases the contact area between the third solder pad 6 and the fourth solder pad 7 via the solder 30.

[0025] (How to assemble the board unit) Fig. 6 is a perspective view of the main board 10 and the sub-board 20 before assembly. Fig. 7 is a perspective view of the main board 10 and the sub-board 20 during assembly. As shown in Figs. 4 and 6, the sub-board 20 has a notch 23 formed by cutting out the X2-direction edge of the first insertion portion 21 in the X1 direction.

[0026] When inserting the first insertion portion 21 of the sub-board 20 into the slit 11 of the main board 10, the sub-board 20 is tilted in the direction indicated by arrow R in FIG. 6 so that the side of the first insertion portion 21 where the notch 23 is provided, i.e., the tip of the X2-side end of the first insertion portion 21, is positioned first, and then the first insertion portion 21 is inserted into the slit 11. Then, after inserting the first insertion portion 21 to a position where the X2-side edge of the slit 11 can be inserted into the entrance of the notch 23, the sub-board 20 is tilted in the direction opposite to the R direction while inserting the X2-side edge of the slit 11 into the entrance of the notch 23, and the entire first insertion portion 21 is passed through the slit 11. As a result, the protrusion 22 of the sub-board 20 is positioned on the Z1 side of the step 12, resulting in the state shown in FIG. 7.

[0027] In this embodiment, the position of the sub-substrate 20 shown in FIG. 7 is defined as the first position P1. As shown in FIG. 7, simply inserting the first insertion portion 21 into the slit 11 causes the first solder pad 4 and the second solder pad 5 to be misaligned in the X direction. Similarly, the third solder pad 6 and the fourth solder pad 7 are also misaligned in the X direction. Therefore, the sub-substrate 20 is slid in the direction of arrow B in FIG. 7 to further insert the X2-side edge of the slit 11 into the notch 23. This allows the X-direction positions of the first solder pad 4 and the second solder pad 5, and the X-direction positions of the third solder pad 6 and the fourth solder pad 7 to be aligned, as shown in FIG. 1.

[0028] In this embodiment, the position of sub-board 20 shown in Fig. 1 is set to second position P2. After sub-board 20 is slid from first position P1 shown in Fig. 7 to second position P2 shown in Fig. 1 and positioned at second position P2, soldering is performed at the locations where first solder pad 4 and second solder pad 5 intersect at right angles, and at the locations where third solder pad 6 and fourth solder pad 7 intersect at right angles, as described above. This completes the connection between main board 10 and sub-board 20.

[0029] At second position P2, the X2-side edge of slit 11 in main board 10 is inserted into notch 23 of sub-board 20. That is, the X2-side edge of slit 11 in main board 10 functions as second insertion portion 15 that is inserted into notch 23. The width of notch 23 is determined according to the thickness of main board 10. In this embodiment, the width of notch 23 is slightly larger than thickness T1 of main board 10.

[0030] When second insertion portion 15 is inserted into notch portion 23, if sub-board 20 tilts from a position perpendicular to main board 10, main board 10 hits the inner surface of notch portion 23, thereby restricting the tilt of sub-board 20. In other words, notch portion 23 and second insertion portion 15 function as a restriction portion for restricting the tilt of sub-board 20.

[0031] (Action and effect) As described above, the substrate unit 1 of this embodiment includes a main substrate 10 and a sub-substrate 20 that is perpendicular to the main substrate 10. A first insertion portion 21 provided on the sub-substrate 20 is inserted into a slit 11 provided in the main substrate 10. A first solder pad 4 provided on the edge of the slit 11 and a second solder pad 5 provided on the first insertion portion 21 are positioned in the X direction of the slit 11 and soldered to each other. The slit 11 and the first insertion portion 21 are shaped so that, with the first insertion portion 21 inserted into the slit 11, they can move from a first position P1, where the first solder pad 4 and the second solder pad 5 are misaligned in the X direction, to a second position P2, where the first solder pad 4 and the second solder pad 5 are aligned in the X direction. The sub-substrate 20 is provided with a notch 23 cut out in the X direction, and the main substrate 10 is provided with a second insertion portion 15 that is inserted into the notch 23. At the first position P1, the second insertion portion 15 is not inserted into the notch portion 23, and at the second position P2, the second insertion portion 15 is inserted into the notch portion 23.

[0032] In this embodiment, by inserting the sub-board 20 into the slit 11 of the main board 10, the first solder pads 4 on the main board 10 and the second solder pads 5 on the sub-board 20 can be positioned and soldered in a perpendicular state. Therefore, the boards can be connected with a simple configuration without using a connector. Also, because no grooves are provided on the inner surface of the slit 11, the configuration of the main board 10 can be simplified and the position of the solder pads can be flexibly changed.

[0033] Furthermore, in this embodiment, the sub-substrate 20 is provided with a notch 23 extending in the X direction, which is the longitudinal direction of the slit 11, and the second insertion portion 15 provided on the main substrate 10 can be inserted into the notch 23 by sliding the sub-substrate 20 so that the positions of the first solder pad 4 and the second solder pad 5 are aligned. The portion of the notch 23 where the second insertion portion 15 is inserted functions as a restriction portion that restricts the tilt of the sub-substrate 20. This improves workability during soldering and also prevents the occurrence of solder cracks.

[0034] When the switch element 3 is mounted on the sub-substrate 20 as in this embodiment, there is a risk that the sub-substrate 20 may tilt when the switch element 3 is pressed. In this embodiment, the tilt of the sub-substrate 20 can be restricted, thereby reducing the risk of solder cracks occurring due to operation of the switch element 3. This improves the reliability of the connection points between the substrates.

[0035] In this embodiment, the width W of the slit 11 is at least 0.3 mm larger than the maximum thickness T2 of the sub-substrate 20, which includes the thickness of the second solder pad 5. This ensures a gap S into which the solder can enter during soldering. This ensures a sufficient contact area with the solder, improving the reliability of the connection between the substrates.

[0036] In this embodiment, the length of the second solder pad 5 in the Y direction, which is perpendicular to the X direction that is the longitudinal direction of the slit 11, is greater than the thickness T1 of the main substrate 10. This allows the second solder pad to be provided over the entire portion that passes through the slit 11, so that the solder 30 that has entered the gap S can ensure a contact area with the solder 30.

[0037] (Variation) (1) In the above embodiment, the second insertion portion 15 of the main board 10 is inserted into the notch portion 23 of the sub-board 20 with a slight play. However, by press-fitting the second insertion portion 15 into the notch portion 23, Press-fitting is preferable. This increases the effect of restricting the tilt of the sub-board 20, which is highly effective in suppressing the occurrence of solder cracks. Therefore, the reliability of the connection between the boards can be further improved.

[0038] (2) The notch and insertion portion for restricting tilt of the sub-board 20 may be provided at positions different from those in the above embodiment. FIG. 8 is a perspective view showing the main portion of the board unit 1A of the first modification. As shown in FIG. 8, the sub-board 20A of the board unit 1A has a notch 24 provided on the side edge of the protrusion 22 in the X2 direction. The main board 10 has an edge extending in the Z direction on the X1 side of the slit 11, and this edge serves as an insertion portion 16 that is inserted into the notch 24. The portion where the insertion portion 16 is inserted into the notch 24 functions as a restriction portion that restricts tilt of the sub-board 20. This improves the reliability of the connection between the boards.

[0039] 8, in addition to the notch 23 and the second insertion portion 15, a new notch 24 and insertion portion 16 are provided, but in this case, the notch 23 and the second insertion portion 15 may be omitted. In the configuration shown in FIG. 8, it is preferable that the insertion portion 16 is press-fitted into the notch 24.

[0040] (3) In the above embodiment, the sub-board 20 has the notch 23 and the main board 10 has the second insertion portion 15. However, the positions of the notch and the second insertion portion may be reversed. FIG. 9 is a perspective view and a front view showing the main portion of a board unit 1B of Modification 2. As shown in FIG. 9, the main board 10B of the board unit 1B has a notch 17 formed by cutting an edge extending in the Z direction in the X2 direction. The sub-board 20B has a second insertion portion 25 inserted into the notch 17 at the X2-direction edge of the protrusion 22. Inserting the second insertion portion 25 into the notch 17 effectively prevents tilting of the sub-board 20. This improves the reliability of the connection between the boards. In the configuration of FIG. 9, the second insertion portion 25 is preferably press-fit into the notch 17.

[0041] (4) In the above embodiment and its variations, when aligning the first solder pad 4 and the second solder pad 5 in the X direction, a position where the contact portion of the sub-board 20 contacts the contact portion of the main board 10 from the X1 side can be provided as a positioning portion. That is, the contact portion can be provided on the edge of the X2 side of the main board 10, and the sub-board 20 can be configured to be spaced from the contact portion in the X direction at first position P1 and to contact the contact portion from the X1 side at second position P2. For example, positioning can be achieved by contacting the edge of the cutout portion 23 from the X1 side with the edge of the X2 side of the slit 11. Alternatively, positioning can be achieved by contacting the edge of the protrusion 22 from the X1 side with the second edge 14 of the step portion 12.

[0042] (summary) A summary of this disclosure is provided below. (1) A substrate unit having a first substrate and a second substrate orthogonal to the first substrate, a first insertion portion provided on the second substrate is inserted into a slit provided on the first substrate, and a first solder pad provided on an edge of the slit and a second solder pad provided on the first insertion portion are positioned in the longitudinal direction of the slit and soldered together; the slit and the first insertion portion are shaped so that, when the first insertion portion is inserted into the slit, they can move from a first position where the first solder pad and the second solder pad are misaligned in the longitudinal direction to a second position where the first solder pad and the second solder pad are aligned in the longitudinal direction; One of the first substrate and the second substrate is provided with a notch cut in the longitudinal direction, and the other of the first substrate and the second substrate is provided with a second insertion portion to be inserted into the notch. Knocked off, A substrate unit characterized in that, in the first position, the second insertion portion is not inserted into the notch, and, in the second position, the second insertion portion is inserted into the notch.

[0043] (2) The board unit according to (1) above, wherein the second insertion portion is press-fitted into the notch portion.

[0044] (3) The substrate unit according to (1) or (2) above, wherein the width of the slit is at least 0.3 mm larger than the maximum thickness of the second substrate including the thickness of the second solder pad.

[0045] (4) The substrate unit described in any one of (1) to (3) above, characterized in that the length of the second solder pad in a direction perpendicular to the longitudinal direction is greater than the thickness of the first substrate.

[0046] (5) The second substrate is provided with the notch portion, The board unit according to any one of (1) to (4) above, wherein the second insertion portion is provided on the first board.

[0047] (6) The first insertion portion is provided with the notch portion, The board unit according to (5) above, wherein the second insertion portion is an edge portion of the slit in the longitudinal direction.

[0048] (7) an abutment portion is provided on an edge of the first substrate in the longitudinal direction; The substrate unit described in any of (1) to (6) above, characterized in that the second substrate has an abutment portion that is separated from the abutted portion in the longitudinal direction at the first position and abuts against the abutted portion in the longitudinal direction at the second position. [Explanation of symbols]

[0049] REFERENCE SIGNS LIST 1, 1A, 1B...board unit, 2...LED display element, 3...switch element, 4...first solder pad, 5...second solder pad, 6...third solder pad, 7...fourth solder pad, 10, 10B...main board, 10a, 10b...board surface, 11, 11B...slit, 12...step portion, 13...first edge portion, 14...second edge portion, 15...second insertion portion, 16...insertion portion, 17...notch portion, 20, 20A, 20B...sub-board, 20a, 20b...board surface, 21, 21B...first insertion portion, 22...protrusion portion, 23...notch portion, 24...notch portion, 25...second insertion portion, 30...solder, P1...first position, P2...second position, S...gap, T1...board thickness of main board, T2...maximum thickness of sub-board, W...slit width

Claims

1. A substrate unit having a first substrate and a second substrate orthogonal to the first substrate, a first insertion portion provided on the second substrate is inserted into a slit provided on the first substrate, and a first solder pad provided on an edge of the slit and a second solder pad provided on the first insertion portion are positioned in the longitudinal direction of the slit and soldered together; the slit and the first insertion portion are shaped so that, when the first insertion portion is inserted into the slit, they can move from a first position where the first solder pad and the second solder pad are misaligned in the longitudinal direction to a second position where the first solder pad and the second solder pad are aligned in the longitudinal direction; a notch portion cut out in the longitudinal direction is provided on one of the first substrate and the second substrate, and a second insertion portion to be inserted into the notch portion is provided on the other of the first substrate and the second substrate; A substrate unit characterized in that, in the first position, the second insertion portion is not inserted into the notch, and, in the second position, the second insertion portion is inserted into the notch.

2. The board unit according to claim 1 , wherein the second insertion portion is press-fitted into the notch portion.

3. 2. The substrate unit according to claim 1, wherein the width of the slit is at least 0.3 mm larger than the maximum thickness of the second substrate including the thickness of the second solder pad.

4. 2. The substrate unit according to claim 1, wherein the length of the second solder pad in a direction perpendicular to the longitudinal direction is greater than the thickness of the first substrate.

5. The second substrate is provided with the notch portion, The board unit according to claim 1 , wherein the second insertion portion is provided on the first board.

6. The first insertion portion is provided with the notch portion, The board unit according to claim 1 , wherein the second insertion portion is an edge portion of the slit in the longitudinal direction.

7. an abutment portion is provided on an edge of the first substrate in the longitudinal direction; The substrate unit according to claim 1, characterized in that the second substrate has an abutment portion that is separated from the abutted portion in the longitudinal direction at the first position and abuts against the abutted portion in the longitudinal direction at the second position.

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