WO2018173103A1 - Printed circuit board - Google Patents

Abstract

A printed circuit board (10) comprises a circuit base (11), and a mounting component (12) joined to a heat radiation member (20) placed on the circuit base. The circuit base has a first area part which is an area for which the positional relationship with the heat radiation member is fixed, and a second area part including an area on which the mounting component is placed. Between the areas of the second area part on which the mounting component is placed, a cut part (13) is provided that is cut facing from the outer edge of the circuit base toward the first area part.

Description

Printed board

The present invention relates to a printed circuit board in which a mounting component is placed on a circuit substrate.

In an electronic device, a structure in which a heat sink, which is a heat radiating member, is joined to a mounting component in order to release heat generated in the mounting component to the outside of the electronic device may be employed. In order to cool the mounting component with high efficiency, it is desired that the flat portion of the heat sink and the mounting component are in close contact with each other without any gap so that heat can be efficiently transferred from the mounting component to the heat radiating member. Patent Document 1 discloses that a structure for thermal management is bonded to an electronic component attached to a circuit substrate.

Special table 2010-506409

Due to individual differences in the size of the mounted components, or due to processing errors when mounting components are placed on the circuit board, the height from the circuit board to the surface of the mounted component that is joined to the heat sink, Variations may occur. When mounting components placed on the circuit base material have variations in height from the circuit base material to the surface to be joined to the heat sink, the circuit base material may be distorted. When the circuit base material is distorted, a gap may be easily generated between the mounting component and the heat sink, so that a desired heat dissipation effect may not be obtained. In addition, it is difficult to perform strict height adjustment for each mounted component so that variation in height is reduced.

The present invention has been made in view of the above, and an object of the present invention is to obtain a printed circuit board that can cool a mounted component efficiently by using a heat radiating member.

In order to solve the above-described problems and achieve the object, the printed circuit board of the present invention includes a circuit base material and a mounting component that is mounted on the circuit base material and joined to the heat dissipation member. The circuit substrate has a first region portion that is a region where the positional relationship with the heat dissipation member is fixed, and a second region portion that includes a region where the mounting component is placed. A cut portion cut from the outer edge of the circuit substrate toward the first region portion is provided between the regions in which the mounted components are placed in the second region portion.

The printed circuit board according to the present invention has an effect that the mounted component can be efficiently cooled using the heat dissipating member.

The perspective view which shows the printed circuit board concerning Embodiment 1. FIG. Plan view of circuit substrate of embodiment 1 The perspective view which shows the printed circuit board concerning Embodiment 2. FIG. Plan view of circuit substrate of embodiment 2 The perspective view which shows the structure containing the printed circuit board concerning Embodiment 3. FIG.

Hereinafter, a printed circuit board according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a printed circuit board 10 according to the first embodiment. The X axis, the Y axis, and the Z axis are three axes that are perpendicular to each other. The direction parallel to the X axis is the first direction, the X axis direction, the direction parallel to the Y axis is the second direction, the Y axis direction, and the direction parallel to the Z axis is the third direction, the Z axis direction. And Of the X axis directions, the direction indicated by the arrow in the figure is the plus X direction, the opposite direction of the plus X direction is the minus X direction, and the Y axis direction and the Z axis direction are the same as in the X axis direction.

The printed circuit board 10 includes a circuit base material 11 and a mounting component 12 placed on the circuit base material 11. The circuit substrate 11 is obtained by printing a wiring pattern on a flat plate that is an insulator substrate. One example of an insulator substrate is a glass epoxy resin. The circuit substrate 11 may be an insulating substrate other than a glass epoxy resin.

The mounting component 12 is a power module or a diode stack, which is an electronic component that requires cooling. The mounting component 12 may be any electronic component that generates heat during operation. The mounting component 12 is joined to the circuit substrate 11 by soldering. In the example shown in FIG. 1, two mounting components 12 </ b> A and 12 </ b> B that are mounting components 12 are mounted on the printed circuit board 10. The mounting component 12A, which is the first mounting component, and the second mounting component 12B are arranged in the X-axis direction with a gap therebetween. The number of mounting components 12 mounted on the printed circuit board 10 is not limited to two, and may be one or three or more.

The mounting parts 12A and 12B are joined to the flat portion 21 of the heat sink 20 which is a heat radiating member. The plane part 21 is a plane parallel to the X-axis direction and the Y-axis direction. The heat sink 20 is disposed with the flat surface portion 21 facing in the plus Z direction. The plurality of fin portions 22 of the heat sink 20 are provided on the back side of the flat portion 21.

The circuit base 11 is provided with four holes 14 penetrating the circuit base 11. The screw 15 as a fixing member is passed through the hole 14 and screwed into the spacer 16 on the flat surface portion 21. The spacer 16 is disposed at a position directly below the hole 14 in the plane portion 21 and is fixed to the plane portion 21. The circuit substrate 11 is screwed to the spacer 16 using the screw 15, thereby ensuring a space corresponding to the mounting components 12 </ b> A and 12 </ b> B between the circuit substrate 11 and the flat portion 21. Is fixed to the heat sink 20. The cut portion 13 is provided between the area of the circuit base 11 where the mounting component 12A is placed and the area where the mounting component 12B is placed.

FIG. 2 is a plan view of the circuit substrate 11 according to the first embodiment. The outer shape of the circuit substrate 11 has a shape in which a cut portion 13 is added to a rectangle. Outer edges E <b> 1 and E <b> 2 are outer edges corresponding to the long sides of the rectangular shape of the circuit substrate 11. In FIG. 2, outer edges E1 and E2 form a straight line parallel to the X axis. The outer edges E3 and E4 are outer edges corresponding to the short sides of the rectangle in the circuit substrate 11. In FIG. 2, outer edges E3 and E4 form a straight line parallel to the Y axis. In addition, the circuit base material 11 may be obtained by adding a cut portion 13 to a shape other than a rectangle.

The circuit substrate 11 has a first region portion 17 that is a region where the positional relationship with the heat sink 20 is fixed, and a second region portion 18 that includes a region where the mounting component 12 is placed. In the first embodiment, the first region portion 17 is fixed to the heat sink 20. The holes 14 are provided at the four corners of the first region portion 17. The range from the position where the two holes 14 on the minus Y direction side of the four holes 14 are provided to the outer edge E1 is the range of the first region portion 17 in the Y-axis direction. The range of the second region portion 18 in the Y-axis direction is from the outer edge E2 to the position before the position where the two holes 14 on the minus Y direction side of the four holes 14 are provided. The second region portion 18 is located next to the first region portion 17 on the minus Y direction side.

The first region portion 17 is fixed to the heat sink 20 with screws 15 shown in FIG. Note that the number of holes 14 in the first region portion 17 is not limited to four and may be plural. The first region portion 17 may be fixed to the heat sink 20 by using a fixing member other than the screw 15 instead of the screw 15.

The second area portion 18 includes an area 19 where the mounting component 12 is placed. In the example shown in FIG. 2, the second region portion 18 includes two regions 19A and 19B, which are regions 19 corresponding to the two mounting components 12A and 12B shown in FIG. The two regions 19A and 19B are arranged in the X-axis direction with a space therebetween.

The cut portion 13 is provided between the region 19A and the region 19B in the second region portion 18. The cut portion 13 has a slit shape that is cut linearly from the outer edge E <b> 2 toward the first region portion 17. The cut portion 13 extends from the outer edge E2 in the plus Y direction and reaches the boundary between the first region portion 17 and the second region portion 18.

In one example, the cut portion 13 is formed by grooving using a router. The cut portion 13 may be formed by a method other than grooving. The second region portion 18 is divided by the cut portion 13 into a portion including the region 19A and a portion including the region 19B.

There may be variations in the height from the surface of the circuit substrate 11 to the surface of the mounting components 12A and 12B that are joined to the flat surface portion 21. The variation in height may be caused by individual differences in the sizes of the mounting components 12A and 12B, or processing errors when the mounting components 12A and 12B are placed on the circuit substrate 11.

Here, assuming the case where the notch portion 13 is not provided in the circuit base material 11, problems that may occur in such an assumption will be described. It is assumed that the circuit substrate 11 is fixed to the heat sink 20 when the joint surface of the mounting component 12B with the flat surface portion 21 is higher than the joint surface of the mounting component 12A with the flat surface portion 21. The circuit substrate 11 is distorted so as to be lifted around the region 19B. When the second region portion 18 is not divided into a portion including the region 19A and a portion including the region 19B, the circuit substrate 11 is distorted, so that the region 19A is included together with the portion including the region 19B. The part can be lifted. In this case, the stress that pushes down the mounting component 12 </ b> A from the circuit substrate 11 toward the flat surface portion 21 is less likely to be applied, so that a gap is easily generated between the mounting component 12 </ b> A and the flat surface portion 21.

As described above, since the notch 13 is not provided, the influence of the bending generated in the circuit base 11 by one mounting component 12 may extend to the region where the other mounting component 12 is placed. is there. In this case, it becomes difficult for the circuit board 11 to closely attach each mounting component 12 to the heat sink 20 without a gap, and the heat dissipation efficiency by the heat sink 20 may be reduced. When a desired heat dissipation effect cannot be obtained due to a decrease in heat dissipation efficiency, performance deterioration or failure of the electronic device due to heat storage in the mounting component 12 is likely to occur. Furthermore, the distortion of the circuit substrate 11 may cause damage to the components by applying excessive stress to any of the components mounted on the printed circuit board 10.

In the printed circuit board 10 according to the first embodiment, the cut portion 13 is provided between the region 19A and the region 19B, so that the portion including the region 19A and the portion including the region 19B in the second region portion 18 are provided. Can be bent independently of each other. The portion including the region 19A is caused to bend corresponding to the height of the joint surface of the mounting component 12A, and the portion including the region 19B is caused to bend corresponding to the height of the joint surface of the mounting component 12B. .

The printed circuit board 10 can prevent the influence of the bending produced in the circuit base material 11 by one mounting component 12 from reaching the area 19 where the other mounting component 12 is placed. Even if bending occurs in the region 19 where one mounting component 12 is placed, a gap is generated between the other mounting component 12 and the heat sink 20 in the region 19 where another mounting component 12 is placed. Generation of such distortion is reduced.

The first region portion 17 and the heat sink 20 are fixed to each other with a certain distance corresponding to the height of the spacer 16. When the region 19 bends in the plus Z direction while the first region portion 17 is fixed, the stress closer to the first region portion 17 in the region 19 that pushes the mounting component 12 in the minus Z direction is stronger. Become. Since the stress that pushes down the mounting component 12 from the circuit substrate 11 toward the flat surface portion 21 is easily applied, a gap is hardly formed between the mounting component 12 and the flat surface portion 21, and the mounting component 12 is brought into close contact with the flat surface portion 21. Can be made. The position at which the mounting component 12 is disposed may be determined in consideration of the ease with which the stress from the circuit substrate 11 is applied.

The printed circuit board 10 can obtain a high heat dissipation effect by the heat sink 20 by bringing each mounting component 12 into close contact with the heat sink 20. The electronic device including the printed circuit board 10 can reduce performance deterioration and failure due to heat storage in the mounting component 12, and can reduce damage to the component due to distortion of the circuit substrate 11. Furthermore, since the printed board 10 does not require strict height adjustment of the mounting component 12 to reduce the height variation, the adjustment work for bringing the mounting component 12 into close contact with the heat sink 20 can be simplified.

According to the first embodiment, the printed circuit board 10 is provided with the cut portion 13 in the second region portion 18, thereby causing a deflection corresponding to the height of the mounting component 12 for each portion including the region 19. . Since the printed board 10 is easily subjected to a stress that pushes down the mounting component 12 toward the heat sink 20, the mounting component 12 is brought into close contact with the heat sink 20, and a high heat dissipation effect by the heat sink 20 can be obtained. Thereby, the printed circuit board 10 has an effect that the mounting component 12 can be efficiently cooled using the heat dissipation member.

In addition, the notch | incision part 13 is not restricted to what is the slit shape cut in linear form. The shape of the cut portion 13 may be a shape including a curved portion or a shape including a bent portion, and may be appropriately modified. By making it possible to arbitrarily set the shape of the cut portion 13, the cut portion 13 can be provided with a high degree of freedom while avoiding the positions of the mounting component 12 and other components.

Embodiment 2. FIG.
FIG. 3 is a perspective view of the printed circuit board 30 according to the second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The printed circuit board 30 includes a circuit base 31 and the mounting component 12 placed on the circuit base 31. The printed board 30 is provided with a cut portion 32 having a shape different from that of the cut portion 13 instead of the cut portion 13 of the printed board 10 of the first embodiment. In the example illustrated in FIG. 3, three cut portions 32 </ b> A, 32 </ b> B, and 32 </ b> C that are cut portions 32 are provided on the circuit base 31.

FIG. 4 is a plan view of the circuit base 31 of the second embodiment. The outer shape of the circuit base 31 is a shape obtained by removing rectangular regions corresponding to the cut portions 32A, 32B, and 32C from a rectangle. The outer edges E1 and E2 are outer edges corresponding to the long sides of the original rectangle. The outer edges E3 and E4 are outer edges corresponding to the short sides of the original rectangle.

The three cut portions 32A, 32B, and 32C are provided in the second region portion 18. The cut portion 32B is located between the region 19A and the region 19B. The cut portion 32 </ b> B has a concave shape cut into a rectangle from the outer edge E <b> 2 toward the first region portion 17. The concave shape consists of two straight lines extending in the Y-axis direction from the outer edge E2 toward the first region portion 17, and a straight line extending in the X-axis direction between the two straight lines. The cut portion 32B reaches the boundary between the first region portion 17 and the second region portion 18 from the outer edge E2 in the Y-axis direction. The second region portion 18 is divided into a portion including the region 19A and a portion including the region 19B by the notch 32B.

The cut portion 32A is located next to the region 19A on the minus X direction side. The cut portion 32A has a shape in which a rectangular region including a corner between two outer edges E2 and E3 is removed from the original rectangle. The shape of the cut portion 32A is composed of a straight line extending in the Y-axis direction from the outer edge E2 toward the first region portion 17, and a straight line extending in the X-axis direction from the outer edge E3. Similarly to the cut portion 32B, the cut portion 32A reaches the boundary between the first region portion 17 and the second region portion 18 from the outer edge E2 in the Y-axis direction. Of the second region portion 18, a portion between the cut portion 32 </ b> A and the cut portion 32 </ b> B has a convex shape protruding from the first region portion 17 in the minus Y direction. The region 19A is included in such a convex portion.

The cut portion 32C is located next to the region 19B on the plus X direction side. The cut portion 32C has a shape in which a rectangular region including a corner between two outer edges E2 and E4 is removed from the original rectangle. The shape of the cut portion 32C includes a straight line in the Y-axis direction extending from the outer edge E2 toward the first region portion 17, and a straight line in the X-axis direction extended from the outer edge E4. Similarly to the cut portions 32A and 32B, the cut portion 32C reaches the boundary between the first region portion 17 and the second region portion 18 from the outer edge E2. Of the second region portion 18, a portion between the cut portion 32 </ b> B and the cut portion 32 </ b> C has a convex shape that protrudes from the first region portion 17 in the minus Y direction. The region 19B is included in such a convex portion.

In one example, the cut portions 32A, 32B, and 32C are formed by cutting using a router. The cut portions 32A, 32B, and 32C may be formed by a technique other than cutting. In addition, the circuit base material 31 should just be provided with the notch part 32B located between the area | region 19A and the area | region 19B, and the other notch parts 32A and 32C do not need to be provided.

In the printed circuit board 30, by providing the cut portion 32B between the region 19A and the region 19B, the portion including the region 19A and the portion including the region 19B can be bent independently of each other. Similar to the first embodiment, the printed circuit board 30 can prevent a gap from being formed between the mounting component 12 and the flat surface portion 21, and can cause the mounting component 12 to adhere to the flat surface portion 21.

According to the second embodiment, the printed board 30 is provided with the notch 32 in the second region portion 18, so that the portion corresponding to the height of the mounting component 12 is caused for each portion including the region 19. . Since the printed board 30 is easily subjected to a stress that pushes down the mounting component 12 toward the heat sink 20, the mounting component 12 is brought into close contact with the heat sink 20, and a high heat dissipation effect by the heat sink 20 can be obtained. Thereby, the printed circuit board 30 has an effect that the mounting component 12 can be efficiently cooled using the heat dissipation member.

One example of an electronic device provided with the printed circuit boards 10 and 30 according to the first and second embodiments is a servo amplifier. The printed circuit boards 10 and 30 may be provided in an electronic device other than the servo amplifier.

In addition, the circuit base materials 11 and 31 are not restricted to what is fixed to the heat radiating member. In the third embodiment, a configuration example of the printed circuit board when the circuit base materials 11 and 31 are not fixed to the heat radiating member will be described.

Embodiment 3 FIG.
FIG. 5 is a perspective view of the structure 40 including the printed circuit board 42 according to the third embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The structure 40 includes a circuit base material 11, a mounting component 12 placed on the circuit base material 11, and a support body 41 that supports the circuit base material 11. The circuit substrate 11 and the mounting component 12 constitute a printed board 42 included in the structure 40.

The two mounting components 12A and 12B, which are the mounting components 12, are joined to the flat portion 51 of the heat sink 50, which is a heat dissipation member. The plane part 51 is a plane parallel to the X-axis direction and the Y-axis direction. The heat sink 50 is arranged with the flat surface portion 51 facing in the plus Z direction. The fin part 22 is provided on the back side of the flat part 51. Since the space for fixing the circuit base material 11 is unnecessary, the flat surface portion 51 may be smaller than the flat surface portion 21 of the heat sink 20 of the first embodiment.

In one example, the support body 41 is a flat plate member disposed in parallel with the X-axis direction and the Y-axis direction. The support body 41 is opposed to the first region portion 17 shown in FIG. It is assumed that the support body 41 is fixed by an electronic device provided with the printed circuit board 42. One example of the support body 41 is a member constituting a housing of an electronic device. The spacer 16 is disposed at a position immediately above the hole 14, and is fixed to a surface of the support body 41 that faces the first region portion 17. The first region portion 17 is fixed to the support body 41 by screwing the first region portion 17 to the spacer 16 using the screw 15. The positional relationship between the first region portion 17 and the heat sink 50 is fixed by being fixed to the support body 41.

It should be noted that the number of screws 15 for fixing the first region portion 17 to the support body 41 is not limited to four and is arbitrary. The first region portion 17 may be fixed to the support body 41 using a fixing member other than the screw 15 instead of the screw 15. The support 41 is not limited to a flat plate member, and may be any member that can support the circuit substrate 11.

The first region portion 17 is fixed to the support body 41 with an interval corresponding to the height of the mounting component 12 between the first region portion 17 and the flat surface portion 51. The support body 41 is fixed to a position where the region 19 shown in FIG. 2 in which the mounting component 12 is placed in the circuit substrate 11 can be bent in the plus Z direction. Since the region 19 bends in the plus Z direction, a stress that pushes down in the minus Z direction is applied to the mounting component 12. In this way, the support body 41 is fixed at a position where the mounting component 12 can be pushed down from the circuit base material 11 toward the flat surface portion 51.

The printed circuit board 42 pushes down the mounting component 12 from the circuit substrate 11 toward the flat surface portion 51, thereby making it difficult for a gap to be formed between the mounting component 12 and the flat surface portion 51, and bringing the mounting component 12 into close contact with the heat sink 50. be able to. Thereby, the printed circuit board 42 can acquire the effect that the mounting component 12 can be efficiently cooled using a heat radiating member similarly to the printed circuit board 10 of Embodiment 1. FIG.

The printed circuit board 42 may include the circuit base material 31 of the second embodiment instead of the circuit base material 11 of the first embodiment. Since the printed circuit board 42 includes the circuit base material 31, the effect that the mounted component 12 can be efficiently cooled using the heat radiating member can be obtained as in the printed circuit board 30 of the second embodiment. The printed circuit board 42 according to the third embodiment is provided in a servo amplifier or other electronic device.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

10, 30, 42 Printed circuit board, 11, 31 Circuit base material, 12, 12A, 12B mounting parts, 13, 32, 32A, 32B, 32C cut-in part, 14 holes, 15 screws, 16 spacers, 17 First area part , 18 Second region portion, 19, 19A, 19B region, 20, 50 heat sink, 21, 51 flat portion, 22 fin portion, 40 structure, 41 support, E1, E2, E3, E4 outer edge.

Claims (6)

A circuit substrate;
A mounting component mounted on the circuit substrate and joined to the heat dissipation member,
The circuit substrate has a first region portion that is a region where the positional relationship with the heat dissipation member is fixed, and a second region portion that includes a region where the mounting component is placed,
A notch portion that is cut from the outer edge of the circuit base toward the first area portion is provided between the areas where the mounting components are placed in the second area portion. A printed circuit board characterized by that. The printed circuit board according to claim 1, wherein the first region portion is fixed to the heat radiating member. The printed circuit board according to claim 1, wherein the first region portion is fixed to a support body that supports the circuit base material. The mounting component includes a first mounting component and a second mounting component,
The first mounting component and the second mounting component are arranged at an interval,
The cut portion is provided between a region in which the first mounting component is placed and a region in which the second mounting component is placed in the second region portion. The printed circuit board according to claim 1, wherein the printed circuit board is a printed circuit board. The printed board according to any one of claims 1 to 4, wherein the cut portion has a slit shape. The printed board according to any one of claims 1 to 4, wherein the cut portion has a concave shape cut into a rectangle.

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