JP2020035990A - Metal base printed circuit board with heat radiation unit and method of forming heat radiation fin - Google Patents

Abstract

To provide a metal base printed circuit board with a heat radiation unit capable of increasing heat radiation efficiency and being downsized by forming a heat radiation fin of a radiator formed upright using a digging tool almost perpendicular to a plane of a metal plate, and a method of forming a heat radiation fin.SOLUTION: A metal base printed circuit board 1 with a heat radiation unit has a heat radiation unit 5 in which a metal foil is pasted to one surface of a metal plate 2 of a predetermined thickness having thermal conductivity and a plurality of plate shaped heat radiation fins 5b formed upright at predetermined intervals is integrally formed on the other surface of the metal plate 2. In a position where the heat radiation unit 5 of the metal base printed board 1 is formed, a through hole 2d for mounting a substrate is formed. In the plurality of radiation fins 5b, heat radiation holes 5c are sequentially formed in a direction inclined with respect to a plane of the metal base printed board 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal-based printed circuit board used in the field of electronic devices, and more particularly, to a metal-based printed circuit board integrally provided with a heat radiating portion having a heat radiating fin for radiating heat generated from an electronic component and the like, and a heat radiating fin formed. About the method.

  2. Description of the Related Art With the demand for higher performance and smaller size of electronic devices, circuit components have been reduced in size, density, and functionality, and mounted on circuit boards at high density. For this reason, the temperature of circuit components is increasing, and heat dissipation is very important. Various methods of heat dissipation have been conventionally proposed, and some of them have been put to practical use.

As an example thereof, Japanese Patent No. 5057221 (Patent Document 1) discloses a metal-based printed circuit board having a heat radiating portion provided with a plurality of plate-shaped heat radiating fins. The heat radiating fins of the heat radiating portion are formed by digging up a metal base printed board and digging down with a tool, thereby forming a plurality of plate-shaped heat radiating fins at predetermined intervals. That is, as shown in FIG. 10, the radiating fins 101 are erected from the metal plate to form the metal base printed circuit board 100 with the radiating portion. Then, heat 103 generated from a heat source 102 such as an electronic component disposed on the metal base printed board is transmitted between the heat dissipation fins 101 and between the heat dissipation fins 101 via the metal base printed board 100 as shown by a dotted line. Heat is dissipated.

JP 2005-93582 A

  The metal-based printed circuit board 100 disclosed in Patent Document 1 described above is usually fixed to an electronic device or the like by fixing means, but generally, a screw or the like is inserted into a through hole such as a screw hole formed in the substrate. Is inserted and fixed. However, since the heat radiation fins 101 are formed in the metal base printed circuit board 100 with the heat radiation parts, the through holes cannot be formed at the positions of the heat radiation fins 101. For this reason, the mounting strength of the metal base printed circuit board 100 is insufficient, and there is a problem that the metal base printed circuit board 100 is detached when shock or vibration is applied. In order to solve such a problem, there is a means for preventing the heat radiation fins 101 from being formed only at the positions of the through holes. However, since a formation area of the heat radiation fins 101 is reduced, a predetermined heat radiation effect cannot be obtained. For this reason, there is a new problem that the heat radiation efficiency is reduced.

  Therefore, an object of the present invention is to form a through hole for mounting a substrate even when the radiating fin is formed upright on the metal base printed circuit board, and furthermore, by sequentially forming the radiating hole in the radiating fin, An object of the present invention is to provide a metal base printed circuit board with a heat radiating portion and a method of forming a heat radiating fin, which can enhance the mounting strength of the printed circuit board and enhance the heat radiation efficiency.

  In order to solve the above-mentioned problem, a metal base printed board with a heat radiating part according to the present invention is configured such that a metal foil is bonded to one surface of a metal plate having a predetermined thickness having thermal conductivity via an adhesive layer. A metal base printed board having, on the other surface of the metal plate, a heat radiating portion integrally formed with a plurality of plate-shaped heat radiating fins formed upright at predetermined intervals, wherein the heat radiating portion of the metal base printed board is provided. In the position where is formed, a through hole for mounting a substrate is formed, and in the plurality of radiating fins, a plurality of radiating holes are sequentially formed in a direction inclined with respect to a plane of the metal base printed board. It is a gist.

  In addition, a metal foil is bonded to one surface of a metal plate having a predetermined thickness via an adhesive layer, and a plurality of plate-like heat radiators vertically formed at predetermined intervals are formed on the other surface of the metal plate. A metal base printed board having a radiator integrally formed with a fin, wherein the metal plate is formed with a through hole for mounting the substrate in advance, and the radiator fin has a blade portion at a tip end moved by a moving device. The digging and raising tool formed with is formed toward the one surface of the metal plate while being moved at a predetermined angle with respect to the other surface of the metal plate to form a slanted plate-like fin by standing down. A digging and raising step, and a retreating step of retreating the digging tool to a position where the next fin is separated by a predetermined distance and digging up, by sequentially repeating the digging up step and the retreating step, It said heat radiation fins of the plate-like upright form, in the digging step, by cutting the through hole while standing form plate-like fins, and summarized in that to form the heat radiation holes in the heat dissipating fins.

  According to the metal base printed board with the heat radiating portion according to the present invention, even at the position where the heat radiating portion of the metal base printed board is formed, the through hole for mounting the board is formed, so that the metal base printed board is The mounting strength can be increased. In addition, since the through holes for mounting the board are formed at any positions of the heat radiating portion where the mounting strength needs to be increased, it is possible to mount the metal base printed board with the required strength. In addition, a plurality of radiating fins are formed with a radiating hole formed by forming a through hole for mounting a substrate, and are sequentially formed in a direction inclined with respect to the plane of the metal base printed board. Since the heat radiation area is expanded and the turbulence is generated in the cooling air flowing through the heat radiation fins, a complicated flow is generated, so that the cooling efficiency can be further improved.

  According to the method of forming the heat radiation fins of the metal-based printed circuit board according to the present invention, the through holes for mounting the board can be easily formed simply by forming them in advance in any positions of the metal plate. Thereafter, a digging process of raising and forming a plate-like fin by moving a digging tool and digging down the metal plate having the through hole, and a retreating process of retracting the digging tool to a position where the next fin is dug are sequentially repeated. Accordingly, in the excavation step in which the through holes for mounting the substrate form the fins, the radiating holes can be naturally formed in the radiating fins. The heat radiation holes changed from the through holes can be sequentially formed in a direction in which the position of the heat radiation fins in the height direction is changed by repeating the excavation process and the retreating process, and inclined with respect to the plane of the metal base printed circuit board. .

It is a sectional side view showing an example of a metal base printed circuit board with a heat radiation part concerning the present invention. It is sectional drawing which shows the radiation fin in which the radiation hole was formed. It is a side view which shows an example of the formation method of a radiation fin. FIG. 4 is a perspective view showing a metal base printed circuit board on which heat radiation fins are formed. It is sectional drawing which shows the radiation fin in which the radiation hole was formed. It is explanatory drawing which shows the movement locus of a digging tool. (A)-(H) are process explanatory views showing the process of forming the radiation fins. (A) thru | or (D) are process explanatory drawings which show the other example of a correction process. It is an explanatory view showing a heat radiation state of a radiation fin by the present invention. It is explanatory drawing which shows the radiation state of the conventional radiation fin.

  The metal base printed circuit board with a heat radiating portion according to the present invention, a metal foil is bonded via an adhesive layer to one surface of a metal plate having a predetermined thickness having thermal conductivity, and the other surface of the metal plate is A metal base printed board having a heat radiating portion integrally formed with a plurality of plate-shaped heat radiating fins formed upright at predetermined intervals, and a board mounting portion is provided on the metal base printed board at a position where the heat radiating portion is formed. And a plurality of radiating fins are sequentially formed in the plurality of radiating fins in a direction inclined with respect to a plane of the metal base printed board.

  Next, a metal base printed board with a heat radiating section according to the present invention will be described in detail with reference to the drawings. A metal base printed board 1 shown in FIG. 1 has a metal base 2 made of copper, iron, an iron-nickel alloy, aluminum, or aluminum whose surface is anodized as a base material. On one surface 2a, a metal foil 3 such as a copper foil is bonded via an insulating adhesive layer (hereinafter referred to as an insulating adhesive layer 4). The insulating adhesive layer 4 uses, for example, a thermosetting resin such as a highly heat-resistant epoxy resin as a base resin. Furthermore, in order to provide high heat dissipation, it is desirable to mix an inorganic filler of fine particles. As is well known, a predetermined wiring pattern is formed on the metal foil 3 by chemical etching. If necessary, a resist made of an electrical insulating film is coated except for the land of the wiring pattern.

  The heat radiating portion 5 is integrally formed at a predetermined position on the other surface 2b of the metal plate 2 which is separated from the one end 2c. The heat radiating section 5 is composed of a plurality of small fins 5a and a plurality of thin plate-like radiating fins 5b formed at the same height. The small fins 5a are formed so as to gradually increase in height from one end 2c of the metal plate 2 to the radiation fins 5b. The base ends of the small fins 5a and the radiation fins 5b are integrally connected from the other surface 2b of the metal plate 2 as shown in FIG. Each of the heat radiation fins 5b is formed to be perpendicular to the plane of the metal plate 2 and to stand up at the same interval.

  The plate thickness of the small fins 5a and the radiation fins 5b can be reduced because they are formed by excavating from one surface of the metal plate 2. The radiating fins 5b preferably have a plate thickness of about 0.03 mm to 1.0 mm for the radiating section 5 used for small electronic components, for example. Further, the interval between the heat radiation fins 5b is arbitrarily set to 0.01 mm or more. The plate thickness of the bottom surface 2f formed between the adjacent radiation fins 5b is formed smaller than the plate thickness of the metal plate 2. In addition, the plate thickness or interval of each heat radiation fin 5b may be formed to be different from each other.

  In the metal plate 2 of the metal base printed board 1, a through hole 2d for mounting the board is formed at the position of the heat radiating portion 5 or at a position separated from the heat radiating portion 5. A female screw is formed on the inner peripheral surface of the illustrated through hole 2d. Then, the metal base printed board 1 is attached by inserting a screw 11 into a through hole formed in a fixture 10 fixed to an electronic device or the like (not shown) and screwing it into a female screw of the through hole 2d. The through-hole 2d may be a mere through-hole in which a female screw is not formed. In this case, for example, a female screw is formed in a through-hole formed in the fixture 10, and a screw 11 is formed from one side of the metal base printed board 1. May be inserted and screwed into the female screw of the through-hole to fix the metal base printed circuit board 1.

  Next, a method of forming the heat radiating portion 5 of the metal base printed board 1 shown in FIGS. 1 and 2 will be described with reference to FIGS. The metal plate 2 is appropriately selected from copper and aluminum as a metal plate having good heat conductivity and good cutting workability. The thickness of the metal plate 2 is set to 0.5 mm to several mm used in a normal electronic circuit. Then, through-holes 2d are formed at one or more places at predetermined positions of the metal plate 2. On one surface 2a of the metal plate 2, a metal foil 3 such as a copper foil is bonded in advance via an insulating adhesive layer 4, and a predetermined wiring pattern is formed on the metal foil 3 by etching. It is configured as a metal-based printed circuit board. Before the heat radiating portion 5 is formed, no electronic component is provided. The through holes 2d formed in the metal plate 2 may be formed in advance in a process before forming a wiring pattern.

  A method of forming the radiation fins 5b on the metal plate 2 on which the wiring patterns and the through holes 2d are formed by using the excavating tool 6 will be described. As shown in FIG. 3, the digging tool 6 has a blade portion 6a formed at the front end on the bottom surface side at right angles to the moving direction. Is set. Incidentally, the width of the blade portion 6a of the excavating tool 6 is set smaller than the width of the metal plate 2 configured as a metal base printed board. Further, as shown in FIG. 3, the excavating tool 6 is attached to a drive device (not shown) so as to be inclined at a predetermined angle θ so that the rear end side is higher with respect to one surface of the metal plate 2. The inclination angle θ is appropriately set depending on the height and thickness of the heat radiation fins 5b, the material of the metal plate 2, and the like, and is set generally from 5 degrees to 20 degrees. Although both sides in the width direction of the excavating tool 6 are formed substantially at right angles, both sides on the bottom surface side where the blade portion 6a is formed may be formed in a tapered shape or an arc shape that becomes narrower toward the bottom surface. .

  The excavating tool 6 is moved by the driving device under the control of the movement locus as shown in FIG. a is a digging and raising process, in which the digging and raising tool 6 moves forward while maintaining the inclination angle θ to cause the metal plate 2 to form fins upright. Next, b is a straightening step, in which a fin is dug up from the position where the fin is formed upright, the tool 6 is raised vertically, and the blade 6a is perpendicular to the plane of the metal plate 2 while making contact with the inclined fin. Orthostatic correction. c is a retreating process, in which the excavating tool 6 is retreated to a position where an excavating allowance D for excavating the next fin is obtained, and a series of circulating operations for bringing the blade portion 6a into contact with the metal plate 2 in the d descending process. Is repeated.

  First, as shown in FIG. 7 (A), after the blade portion 6a of the excavating tool 6 is brought into contact with a predetermined position on one side of the metal plate 2 which is separated from one end side, the excavating process of a shown in FIG. When the digging tool 6 is inserted into the metal plate 2 by a driving device (not shown) in a direction indicated by an arrow at a predetermined angle θ, the blade 6a of the digging tool 6 bites into one surface 2b of the metal plate 2. As shown in FIG. 7A, small and thin small fins 5a are formed upright. At this time, it is desirable that the pressure at which the excavating tool 6 is inserted into the metal plate 2 be set to such an extent that the metal plate 2 is not deformed or stressed. For this reason, since the depth for inserting the excavating tool 6 is shallow, the small fins 5a are formed upright and low.

  After the blade portion 6a of the digging tool 6 erects and forms the small fin 5a, as shown in FIG. 7B, the blade portion 6a of the digging tool 6 is removed from that position as in the straightening process of b in FIG. Ascend vertically. At this time, the blade 6a is straightened upright with respect to the plane of the metal plate 2 while abutting on the small fins 5a.

  Next, as shown in FIG. 7 (C), the excavating tool 6 is moved as in the retreating step c shown in FIG. 6, and the blade portion 6a is moved to the position where the excavating allowance D on the upstream side (left side in the figure) is obtained. In the step of d shown in FIG. 6, the small fins 5 a are brought into contact with each other, and the excavation process is performed by making the small fins 5 a bite deeper than when the small fins 5 a are formed upright. Form. The next small fin 5a formed upright in this manner is also raised vertically in the vertical direction by raising the blade portion 6a vertically as in the correction process shown in FIG. 6B.

  Thereafter, the excavating step shown in FIG. 7D, the correcting step shown in FIG. 7E, the retreating step shown in FIG. 7F, and the descending step are sequentially repeated, and the excavating tool 6 is sequentially excavated deeply. The small fin 5a is formed to be higher than the small fin 5a that has been formed, and the step of forming the small fin is completed when the blade portion 6a reaches a predetermined depth.

  Subsequent to the step of forming the small fins 5a, the process proceeds to the step of forming the radiation fins 5b, and a plurality of radiation fins 5b having the same height as shown in FIG. 2 are formed. That is, as shown in FIG. 7 (F), after the blade portion 6a of the digging tool 6 is brought into contact with the metal plate 2 from a position where the digging allowance D can be obtained on the upstream side with respect to the small fin 5a formed last. 7 (G), the radiating fins 5b are formed upright as shown in FIG. 7 (G).

  As described above, the metal plate 2 of the metal base printed board 1 has the through holes 2d for mounting the board at positions where the heat radiation fins 5b are formed in advance. In the step of forming the radiation fins 5b shown in FIG. 7G, the through holes 2d are also cut by the blade 6a of the excavating tool 6 at the same time. At this time, a radiation hole 5c is formed in the radiation fin 5b by the through hole 2d.

  Thereafter, by performing a straightening step shown in FIG. 7H, the heat radiation fins 5b are formed to stand upright to the plane of the metal plate 2. As a result, as shown in FIG. 5, a radiation hole 5c is formed in the radiation fin 5b, and the radiation hole 5c is formed in a slightly vertically long elliptical shape because the digging tool 6 moves while being inclined. Subsequently, the blade 6a of the digging tool 6 is retracted to a position where the digging allowance D is obtained on the upstream side, and the blade 6a of the digging tool 6 is brought into contact with the metal plate 2 as shown in FIG. Then, by moving the radiating fin 5b to a predetermined depth while maintaining the inclination angle, the next radiating fin 5b is formed upright. At this time, since it is displaced to the dimension of the digging allowance D, when the radiating fin 5b is formed upright by the blade portion 6a of the digging tool 6, the radiating hole 5c is closer to the metal plate 2 than the position of the radiating fin 5b formed before. Formed at a lower position.

  In this manner, similarly to the above-described step of forming the small fins 5a, the digging step, the correcting step, the retreating step, and the descending step are sequentially repeated by the blade portion 6a of the digging tool 6, whereby the plurality of radiation fins 5b are formed. It is formed upright. Then, in the position where the through hole 2d for mounting the substrate is formed in the metal plate 2, the through hole 2d is simultaneously cut by the blade portion 6a of the excavating tool 6 in the step of forming the radiation fin 5b, and corresponds to the through hole 2d. Each of the plurality of radiating fins 5b has a radiating hole 5c.

  As described above, the radiating fins 5b are vertically formed on the metal plate 2 by the excavating tool 6, so that the bottom surface 2f is formed between the adjacent radiating fins 5b. 2 is formed smaller than the plate thickness.

  By performing the step of forming the radiating fins 5b in this manner, the radiating portion 5 having the plurality of radiating fins 5b perpendicular to the metal plate 2 is formed as shown in FIGS. Furthermore, among the vertical radiating fins 5b, a plurality of radiating holes 5c are formed in a plurality of radiating fins 5b near the position where the through hole 2d for mounting the substrate is formed. As a result, as shown in FIG. 9, for example, heat 8a generated from a heat source 8 such as an electronic component is radiated between the radiating fins 5b through the metal plate 2 and through the radiating fins 5b as indicated by dotted lines. However, since the heat 8a has the property of rising in the vertical direction, the heat 8a smoothly rises between the heat radiation fins 5b and is radiated. Therefore, the heat radiation efficiency can be increased. Further, since the heat 8a passes through the heat radiation holes 5c formed in the heat radiation fins 5b, turbulence is generated in the heat radiation fins 5b, and the internal heat 8a is not stagnated and is heated by the brain. Can be

  In the above-described forming method of the present invention, the radiating fins 5b are straightened upright with respect to the plane of the metal plate 2. However, in order to further enhance the radiating effect, the radiating fins 5b are set within 10 degrees. The heat fins 5b may be formed with the heat radiating holes 5c so that the heat 8a can easily pass through the heat radiating holes 5c, and the heat radiating effect is enhanced. Further, the heat radiation fins 5b may be curled as shown in FIG. 10 without being formed perpendicular to the plane of the metal plate 2, and in this case, the above-described straightening step can be omitted.

  On the other hand, on the upstream side of the heat radiating fin 5b opposite to the small fin 5a, an inclination from the bottom surface 2f to one surface of the metal plate 2 is formed as shown in FIG. The work surface 2e is left. The inclined surface which has been the processed surface 2e can function as a heat dissipation surface. In addition, a flange portion 7 having a thickness of the metal plate 2 is formed behind the processing surface 2e.

  Further, on both sides of the plurality of radiation fins 5 b formed on the metal plate 2, the flange portions 7 of the metal plate 2 having the thickness are formed. The flange 7 can be formed by setting the width of the excavating tool 6 to be smaller than the width of the metal plate 2. As a result, as shown in FIG. 1, the flange 7 formed on the radiator 1 is formed so as to surround the radiator 5.

  The heat radiating portion 5 is formed at a position corresponding to an electronic component such as an integrated circuit 8 disposed on a wiring pattern formed by the metal foil 3 on one surface 2a of the metal plate 2. By disposing the heat radiating portion 5 in such a positional relationship, the heat generated from the integrated circuit 8 is transmitted to the heat radiating portion 5 via the metal plate 2 and is radiated from the surface of the heat radiating fin 5b to the air. In addition, the base ends of the small fins 5a and the radiation fins 5b are integrally connected to a bottom surface 2f formed on one surface of the metal plate 2, and the thickness between the bottom surface 2f and the one surface 2a of the metal plate 2 is reduced. Experiments have also shown that the heat generated from the integrated circuit 8 is quickly transmitted to the heat radiating portion 5 because the thin film is formed, so that the heat radiating efficiency is improved. As the electronic components, there are a power transistor, a resistor, a power module, and the like in addition to the integrated circuit 8.

  As described above, the present invention has been specifically described based on the embodiments. However, it is needless to say that the present invention is not limited to the above embodiments and can be variously modified without departing from the gist of the present invention. For example, the metal-based printed circuit board may be formed in an appropriate shape other than a square, similarly to a general printed circuit board. Further, in the above-described embodiment, the heat radiating portion is formed at one place, but may be formed at a plurality of places according to an arrangement position of an integrated circuit or the like which requires heat radiating. In this case, the direction of the radiating fins may be changed at an appropriate angle for each radiating portion. Further, since the metal-based printed circuit board uses a metal plate as a base material, another mechanical component or the like may be attached, or a support portion or the like may be provided so as to attach the mechanical component.

DESCRIPTION OF SYMBOLS 1 Metal base printed board 2 Metal plate 2a One surface 2b The other surface 2d Through hole 3 Metal foil 4 Insulating adhesive layer 5 Heat radiating part 5a Small fin 5b Heat radiating fin 5c Heat radiating hole 6 Digging tool 6a Blade part

Claims (2)

A metal foil having a predetermined thickness is provided with a thermal conductivity, and a metal foil is attached to one surface of the metal plate via an adhesive layer, and the other surface of the metal plate has a plurality of plate-like members formed upright at predetermined intervals. A metal base printed board having a heat radiating portion integrally formed with heat radiating fins
At a position where the heat radiation portion of the metal base printed board is formed, a through hole for mounting the board is formed,
A metal base printed circuit board with a heat radiating part, wherein a plurality of heat radiating holes are sequentially formed in the plurality of heat radiating fins in a direction inclined with respect to a plane of the metal base printed circuit board. A metal foil is attached to one surface of a metal plate having a predetermined thickness via an adhesive layer, and a plurality of plate-shaped heat radiation fins vertically formed at predetermined intervals are formed on the other surface of the metal plate. A metal-based printed circuit board having an integrally formed heat radiating portion,
In the metal plate, a through hole for mounting the substrate is formed in advance,
The radiating fin is directed toward a first surface of the metal plate at a predetermined angle with respect to the other surface of the metal plate, with a digging tool having a blade portion formed on a tip side moved by a moving device. A digging step of erecting the inclined plate-shaped fin by moving and digging down, and a retreating step of retracting the digging tool to a position where the next fin is separated by a predetermined distance and digging up,
By sequentially repeating the excavation step and the retreating step, a plurality of plate-shaped radiating fins are formed upright,
In the excavation step, the heat-dissipating holes are formed in the heat-dissipating fins by cutting the through-holes while forming plate-like fins upright.

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