JP3432477B2 - heatsink - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a heat sink for dissipating heat received from a heat generating body to the outside by using a refrigerant, and more particularly to a computer, a communication, and an automobile. Flat heater suitable for heat dissipation from widely used heating elements
The present invention relates to improvement of a top panel type heat sink. 2. Description of the Related Art High-density packaging products are used in the fields of computers, communications, automobiles, and the like. In order to dissipate heat from the high-density packaging products, a flat heater using a refrigerant is used.
A top panel heat sink is used. In this type of heat sink, as shown in FIG. 2 , a brazing portion 16B joins a substrate 12 and an upper concavo-convex plate 14 having a projecting portion 14a communicating with each other to form a coolant passage 22. Is formed. Brazing is for substrate 1
A special brazing plate having a two-layer structure of a low-melting aluminum alloy and normal aluminum is used between the upper and lower concave and convex plates 2 and 14 and the low-melting aluminum alloy surface is put into a high-temperature bath in a pressure contact state to reduce the temperature. The melting point of the aluminum alloy is melted and joined, but the temperature in the high-temperature bath is required to be higher than the temperature required for complete annealing of the aluminum, so that the upper uneven plate 14 bends and undulates. On the other hand, the substrate 12 is also annealed, so that it cannot maintain a planar state, and thus the liquid-tightness is reduced, and the annealing strength of the substrate 12 lowers the fastening strength of the screw for attaching the substrate 12 to the heating element. [0004] Thus, the current flat heat panel
Despite the drawbacks of swelling and bending of the heat dissipating member and the lowering of the flatness of the board , the type heat sink is used as it is for mounting products where the mounting density is higher, the size is more compact, and the heat generation is increasing. Has been
The heat sink has a drawback that a large amount of heat from such a mounted product cannot be effectively dissipated. [0005] An object of the present invention is to form a substrate without lowering the flatness of a substrate and maintaining high mechanical strength and high thermal conductivity. And a flat panel heat sink. Means for Solving the Problems A means for solving the problems of the present invention comprises a plurality of heat dissipating members made of a heat conductive material, and these plural heat dissipating members are joined to each other by a laser welding joint. a plurality of heat dissipating members, the flat plate and a number of indentations and the flat plate bonded refrigerant dotted joined to flat plate so as to form a plurality of floating portions to form the refrigerant passage to be flow between the flat plate irregularities and a peripheral edge of the flange
The laser welded joint is formed so as to join the flat plate to the peripheral edge of the dent of the concave and convex plate and the flange, and to provide a heat sink. [0007] As described above, the flat heat panel type heat sink and the flat plate and the concave and convex plate, which are the heat radiating members, are provided.
When the peripheral edge and the flange are joined to each other by the laser welding joint, the heat dissipation member maintains higher mutual thermal conductivity and higher joint strength than the conventional technique of joining by caulking or brazing. it is as possible out to be. Also, since there is no thermal deformation unlike brazing, a high flatness of the heat sink mounting surface can be maintained, and the heat dissipation effect of the heat sink is not diminished. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings . FIG. 1 shows a flat heat sink 10H1 using a refrigerant, which is a form of a flat heat sink 10H1.
A heat sink 10H11 of a top panel type is shown. This heat sink 10H11 is composed of a flat substrate (flat plate) 121 made of aluminum, which is one of the heat dissipating members 12, and an upper concave-convex plate 14 made of aluminum, which is another heat dissipating member 14.
Consists of one and one. As shown in FIG. 1C, the concavo-convex plate 141 has a large number of depressions 18 formed by being recessed downward so as to come into contact with the substrate 121 in a plane. The portion other than the portion 18 is a raised portion 20 that is raised at an interval from the substrate 121. Therefore, the concave and convex plate 141 is in the form of a plate in which the concave portion 18 is a concave portion and the raised portion 20 is a convex portion, and the refrigerant passage 22 is formed between the substrate 121 and the raised portion 20. Although the dents 18 can be formed to be appropriately scattered, in the illustrated embodiment, as shown in FIG. 1A, the dents 18 are formed so as to be aligned vertically and horizontally. It is in the shape of a letter. The periphery of the concave and convex plate 141 is the refrigerant injection port 2
Except for the portion forming 4, a flange 26 is formed which comes into contact with the substrate 121 in a planar manner. Reference numeral 25 denotes a mounting screw through hole formed in alignment with the edge of the substrate 121 and the flange 26 of the uneven plate 121. As shown in FIGS. 1A and 1C, the laser welding joint 161 of the heat sink 10H11
It is formed by seam welding while irradiating a laser beam from a laser welding machine such as a YAG laser welding machine along the substrate 121 and the portion of the uneven plate 141 which comes into planar contact with the substrate 121. [0011] More specifically, the laser welded joint 1
Reference numeral 61 denotes seam welding along the entire length of the flange 26 of the uneven plate 141 (peripheral portion excluding the refrigerant injection port 24), and ring welding in an elliptical shape around all the recesses 18 of the uneven plate 141. Formed by After the coolant is injected into the coolant passage 22, the coolant inlet 24 is closed so that the opening wall thereof contacts the substrate 121, and the contact portion is similarly closed in a liquid-tight manner by laser welding. Either the welding of the flange 26 or the welding around the recess 18 may be performed first,
In consideration of mutual positioning between the flange 26 and the uneven plate 141, it is preferable that the welding of the flange 26 be performed first. As described above, when the plurality of heat dissipating members 12, 14 made of a heat conductive material such as a flat plate and a concavo-convex plate are joined to each other by the laser welding joint 16, the heat dissipating members 1
2 and 14 are physically integrated by the laser welding joint portion 16 to be in the same state as if they were integrally molded, so that the thermal conductivity between the heat radiating members 12 and 14 can be improved, and Can also remarkably improve the mechanical joining strength. According to the present invention, as described above, flash
The heat panel type heat sink is made of flat plate and uneven plate .
Since the joint surface with the peripheral edge and the flange is joined together by a laser welding joint, compared to the case of joining by caulking or brazing of the prior art, the mutual heat conductivity of the heat dissipating member and high Mechanical bonding strength can be maintained. Further, the heat sink, since no accompanied by thermal deformation as is the case by brazing, it is possible to maintain a high flatness of the mounting surface of the heat sink, it is not to diminish the heat dissipation effect of the heat sink .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a flat heat panel type heat sink according to an embodiment of the present invention, and FIG.
FIG. 1B is a cross-sectional view taken along the line BB, and FIG. 1C is an enlarged cross-sectional view of a part of FIG. FIG. 2 is an enlarged cross-sectional view of a part of a conventional flat heat panel type heat sink. [Description of Signs] 10H1 Flat heat sink 12 Heat radiating member 14 Heat radiating member 16 Laser welded joint 18 Indented portion 20 Floating portion 22 Refrigerant passage 24 Refrigerant inlet 26 Flange 121 Flat substrate 141 made of aluminum Aluminum upper uneven plate 161 Laser Weld joint

Continuation of the front page (56) References JP-A-6-275747 (JP, A) JP-A-11-40715 (JP, A) JP-A-10-125831 (JP, A) JP-A-8-172150 (JP, A) , A) JP-A-7-318282 (JP, A) JP-A-10-38484 (JP, A) Table 11-11-505372 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB (Name) H01L 23/34-23/473

Claims (1)

(57) Claims 1. A plurality of heat dissipating members made of a heat conductive material are provided, and the plurality of heat dissipating members are joined to each other by a laser welding joint. periphery of the flange to be joined to a number of indentations and the flat plate scattered to joined to the plates such refrigerant to form a number of floating portions to form the refrigerant passage to be flow between the flat plate, and the plate consists of a concave-convex plate having bets, the laser weld joint, a heat sink, characterized in that it is formed so as to join the said indentation of the periphery and the flange of the uneven plate and the flat plate.