JPH0254975A - Peltier element - Google Patents

Abstract

PURPOSE:To enable a relative position error with a heat-radiation fin, especially a large slope, to be absorbed by forming the junction surface with an electrical heating element or a cooling element in spherical or cylindrical surface. CONSTITUTION:A cooling surface 3 of a Peltier element 2 joined to an electrical heating element 1 consisting of for example a semiconductor laser is formed in projecting spherical surface shape and the cooling surface 3 is joined to a flexible structure heat transfer body 5 fixed to the rear surface of a cooling fin 4 and a junction surface 7 in vecessel spherical surface shape formed by an improved heat-conduction type flexible film 6. By making the cooling surface 3 and the junction surface 7 to be in spherical surface in this manner, a large degree of three-dimensional freedom is given to the posture of the cooling fin 4 and a relative slant of the junction surface is greatly allowed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Utilization Public Expenses> The present invention relates to a Peltier element used for cooling electronic components.

<Prior Art> In recent years, multi-beam semiconductor lasers for optical heads and higher output have been studied. However, in this case, problems arise such as wavelength fluctuation and shortened lifespan due to the increase in the amount of heat generated by the semiconductor laser. As a means to solve such problems, forced cooling using a small Peltier element with good heat absorption performance is extremely effective.

The Peltier element is also called an electronic cooling element, a thermo module, etc., and has an appearance as shown in FIG. In the drawing, reference numerals 41 and 42 indicate electrically insulating flat plates, 43 electrode patterns formed on opposing inner surfaces of these flat plates 41 and 42, 44 semiconductor columns or conductor columns, and 4
5 is a lead wire, and a series circuit is formed by sandwich-bonding a plurality of couples of different semiconductor pillars or conductor pillars 44 to an electrode pattern 43, and a lead wire 45 is connected to each electrode pattern. ing. When a direct current is passed through this lead 945, due to the Peltier effect, heat is absorbed at the joint between one flat plate 41 and each semiconductor block or conductor pillar 44, and similarly, heat is absorbed at the joint between one flat plate 41 and each semiconductor block or conductive pillar 44, Heat is released at the junction with the forest or conductor pillar 44. That is, heat is continuously pumped from one flat plate 41 to the other flat plate 42.

For example, in a laser for optical transmission, a Peltier element is mounted in a package that also serves as a heat sink, and a laser element is provided on the Peltier element. In this case, since the amount of heat generated by the laser is relatively small, the package is naturally air-cooled, so there is no need to assemble large heat dissipation fins, and since a flexible optical fiber is used to extract the laser beam, the laser element There is no particular problem because the positional accuracy is relatively poor.

However, when cooling a semiconductor laser for an optical head, the laser must be assembled with other optical components with high relative positional accuracy.

In a structure in which a heat dissipation fin, which is larger than the laser, is placed on the back of the laser together with a Peltier element, it is very difficult to adjust the position when assembling the laser, and there is a great risk that the position will fluctuate even after assembly. In particular, in the case of a method in which the radiation fins are cooled by natural air, it is necessary to make the radiation fins larger, so the above-mentioned problems become even more important. Furthermore, in a structure in which the radiation fins are fixed to the outside of the device case, mechanical interference occurs due to positional errors between the cooling unit and the radiation fins, which adversely affects the positional accuracy of the laser, as in the case described above. Therefore, in order to solve such problems, it is necessary to employ a flexible structure that can absorb positional errors between the Peltier element and the heat radiation fin.

To solve this problem, Fig. 5(a), (
As shown in b), between the heat dissipation plate side plate 51 and the heat dissipation fin side plate 52 of the Peltier element, a knitted wire 53 made of flexible thin metal wires knitted in a flat or original shape or a bundled wire 54 made of a bundle of thin metal wires is used. A possible method is to connect them. In addition, as shown in FIG. 5(C), a fluid 56 with good thermal conductivity is sealed between the heat sink side plate 51 and the heat sink side plate 52 of the Peltier element in the gap between the opposing planes of two metal blocks 55. A structure in which a heat transfer body 57 having such a structure is provided is also conceivable.

<Problem to be solved by the invention> However, when using the braided wire 53, this $1 $53
Both ends of the board must be joined to the mating plates 51 and 52 by caulking, screw tightening, or soldering to ensure thermal continuity; As a result, the thermal resistance is large, and in soldering, the thermal conductivity of the solder material is low, and the wire material in the vicinity is hardened by the solder and loses its flexibility. On the other hand, when the bundled wire 54 is used, even if the bonding light plates 51 and 52 are not flat or have a WA shape, the deviation can be absorbed and relatively uniform mechanical bonding can be achieved. However, the problem is that the thermal resistance is large because the joint is a point contact, similar to the case with Stainless Steel. Furthermore, both the sash 53 and the wire bundle 54 have a large thermal resistance because they are long in the direction of heat conduction and have small cross-sectional areas. Therefore, more space is required to cover these shortcomings.

In addition, in the case of the heat transfer body 57, there is a degree of freedom in swinging (oscillation) due to the gap between both metal blocks 55, but the thermal conductivity of the fluid 56 to be filled, for example, liquid metal, is lower than that of general metals. Since the gap is about two orders of magnitude smaller than that, the gap must be made as small as 0.4 nm or less, so the degree of freedom, that is, the positional error that can be absorbed is small. Also, since the fluid 56 is used,
There are problems with leakage and restrictions on the joining position.

Therefore, the present inventors previously proposed a compact heat transfer body with a flexible structure having a relatively large three-dimensional degree of freedom.

A heat transfer structure including such a heat transfer body is shown in FIG. As shown in the figure, a flexible structure heat transfer body 61 is made by filling a mixture of a powder of a high heat conductive material and a viscous material with good heat conductivity around an aggregate of thin wires of a high heat conductive material such as steel. It is fixed to the back surface of the radiation fin 63 via a flexible membrane 62 with good thermal conductivity such as silicone rubber. On the other hand, a heating element 66 that is a semiconductor laser and a Peltier element 67 that is fixed to the heating element 66 and forcibly cools it are integrated into a heating element mounting part 65 in the device case 64 by a heat insulating screw 68 and a heat insulating spacer 69. It is assembled into. By assembling the heat dissipation fins 63 to the device case 64 using the heat insulating screws 68 and the heat insulating spacers 69, the flexible structure heat transfer body 61 is compressed and deformed, and the Peltier element 67
is pressed against the heat dissipation surface. As a result, a thermal path from the Peltier element 67 to the radiation fins 63 is formed with a thermal resistance equivalent to that of a rigid joint, but at this time, there is a relative position error between the heating element 66 and the radiation fins 63 which are arranged in close proximity. is absorbed by the flexible structure heat transfer body 61 having three-dimensional degrees of freedom.

However, in this case, since the deformation of the flexible structure heat transfer body 61 in the thickness direction is used to join adjacent planes, there is a problem that the range in which the relative inclination of the two planes is allowed is small. For example, when a flexible structural heat transfer body 61 with a joint surface of 201 squares and a thickness of 5 m is used, the relative angle of inclination that can be absorbed by the thickness is about 5 degrees.

In view of these circumstances, it is an object of the present invention to provide a Peltier element that can absorb relative positional errors, particularly large inclinations, with respect to heat radiation fins.

Means for Solving the Problems〉 The Bertier element according to the present invention that achieves the above object has a heat absorbing part formed by forming an electrode pattern surface on the back side of the joint surface with the heat generating object, and a joint surface with the heat dissipating body. In a Peltier element consisting of a heat dissipation section formed with an electrode pattern surface formed on the back surface, and a plurality of semiconductor elements or conductive elements sandwiched and bonded between the two electrode patterns, there is a heat dissipation section between the heat generation target and the heat absorption section. Alternatively, at least one of the heat radiating body and the heat radiating portion may be joined via a spherical or cylindrical surface.

Effect〉 Since the heating object or heat dissipation body and the Peltier element are joined via the spherical or cylindrical joint surface, the relative position error between the two is due to the deviation in the spherical or cylindrical joint surface. Absorbed.

Example of application Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows a preferred embodiment. As shown in the figure,
For example, the heat dissipation surface 3 of the Peltier element 2 bonded to the heating element 1 made of a semiconductor laser is formed into a convex spherical shape, and the heat dissipation surface 3 is a flexible structure heat transfer material fixed to the back surface of the heat dissipation fin 4. 5 and a concave spherical joint surface 7 formed of a flexible film 6 with good thermal conductivity.

By making the heat dissipation surface 3 and the joint surface 7 spherical as shown in Part B, a large three-dimensional degree of freedom is given to the posture of the heat dissipation fin 4, and the relative inclination of the joint surfaces is greater than when joining flat surfaces. 5 times or more is allowed.

Therefore, it is possible to absorb the relative positional error between the Peltier element 2 and the heat dissipating fin 4 when the heat dissipating fin 4 is assembled to the device case 10 using the cross-sectional screw 8 and the cross-sectional spacer 9 while aligning the joint surface 7 and the heat dissipating surface 3. be able to. Further, it is most suitable when the heat dissipation path is intentionally bent due to space or structural constraints, and when the heating element 1 is a semiconductor laser, a degree of freedom can be given to IIm in the beam emission direction. Furthermore, since the radiation fins 4 have a large degree of freedom, they can be accurately positioned in accordance with the direction of the wind, such as when the radiation portion is forcibly air-cooled.

By making the joint surface 7 spherical, the flexible structure heat transfer body 5 and the highly thermally conductive flexible membrane 6 can be joined more reliably and the joint area can be increased compared to a flat surface.

The flexible structure heat transfer body 5 is made of, for example, a copper net SS coalescence such as a non-woven fabric as the main heat conductor, and the voids thereof are filled with copper powder having a particle size of 100 μm and a silicone oil compound which is a viscous material with good thermal conductivity. It is sufficient to use a film filled with a mixture of the above, and as the good thermally conductive flexible membrane 6, a thermally conductive silicone rubber molded membrane having a thickness of, for example, 0.3 mm may be used.

In the Peltier element 2, the back surface of the heat dissipation surface 3 has, for example, a semiconductor element assembled thereon and needs to be electrically insulated. It is made of hard alumina ceramic similar to the element. However, if the heat dissipation surface 3 is formed of a high thermal conductivity metal such as steel or the above-mentioned flexible structure heat transfer body and a good heat conductive flexible film on the heat dissipation surface made of the alumina ceramic flat plate of a normal Peltier element, the heat transfer efficiency will be improved. further improves. It goes without saying that the same applies to the following examples.

In addition, in this embodiment, the radius of curvature of the convex spherical heat dissipation surface 3 is made relatively small, but if a relatively small relative position error is to be absorbed, a spherical surface with a large radius of curvature can be used to ensure reliable thermal bonding. can be realized.

Note that if the relative position error due to the relative inclination of the heat dissipation surface 3 and the joint surface 7 can be absorbed only in one direction, the same effect can be obtained by making the heat dissipation surface 3 and the joint surface 7 cylindrical surfaces instead of spherical surfaces. Able to achieve purpose.

FIG. 2 shows another embodiment, which is the same as the embodiment described above except that the heat radiation surface 3 is a concave spherical surface and the joint surface 7 is a convex spherical surface. In this case as well, it goes without saying that a cylindrical surface may be used instead of a spherical surface if the relative position error can be absorbed only in one direction.

FIG. 3 shows yet another embodiment. In this embodiment, another Peltier element 11 is fixed to the back surface of the heat dissipation fin instead of the flexible structure heat transfer body 5 and the highly thermally conductive flexible film 6. It is. This Peltier element 11 has a heat absorbing surface 12 having a convex spherical shape and is connected to a concave spherical heat dissipating surface 3 of the Peltier element 2 . In this way, by using two Peltier elements and connecting them via a spherical joint surface, the cooling effect can be increased. In addition, by interposing a good heat conductive material such as silicone grease between the joint surfaces of the two Peltier elements 2 and 11, it is possible to improve the slippage and further ensure thermal bonding. .

In addition, in this embodiment, if a spherical joint surface, for example, as shown in the above-mentioned embodiment is further provided between the heat dissipation surface of the Peltier element 11 and the heat dissipation fin 4, the degree of freedom will be further increased.

In the embodiment described above, an example was shown in which a joint surface made of a spherical or cylindrical surface was provided between the Peltier element and the heat dissipation fin, but a joint surface made of a spherical or cylindrical surface was provided between the Peltier element and the heating element. It goes without saying that the same effect can be obtained even if

<Effects of the Invention> As explained above, since the Peltier element of the present invention has a spherical or cylindrical joint surface with the heating element or the heat radiating element,
By aligning the joining portions of the heat radiating elements or heat radiating elements placed close to each other with this joint surface, a greater degree of freedom than ever before can be given to the joining posture of the heat radiating elements, and the range of application in cooling fraction meters is wide.

[Brief explanation of the drawing]

FIGS. 1 to 3 are external views showing how the Peltier element according to the embodiment of the present invention is used, FIG. 4 is an external view of the Peltier element, and FIGS. Figure 6 is an explanatory diagram showing the heat transfer method. In the drawing, 1 is a heating element, 2 is a Peltier element, 3 is a heat radiation surface, 4 is a heat radiation fin, and 5 is a flexible 1 is a structural heat transfer body, 6 is a flexible film with good thermal conductivity, 7 is a joint surface, 10 is a device case, 11 is a Peltier element), and 12 is a heat absorption surface.

Claims (1)

[Claims] A heat absorbing part formed by forming an electrode pattern surface on the back side of the surface to be joined with the heat generating object, a heat radiating part formed by forming the electrode pattern surface on the back surface of the joint surface with the heat radiating body, and a sandwiched between the two electrode patterns.
In a Peltier element consisting of a plurality of semiconductor elements or conductor elements bonded together, at least one of the heat generating object and the heat absorption part or the heat radiating body and the heat radiating part is connected through a spherical or cylindrical surface. A Peltier element characterized by being bonded.