JP2019067981A - Heat sink - Google Patents

Abstract

To provide a heat sink capable of restraining acceleration of deterioration, while realizing efficient cooling.SOLUTION: A heat sink 2 includes a coolant passage 20. The coolant passage 20 includes a first passage part 23 and a second passage part 24 extending in a first direction D1, a third passage part 25 extending in a second direction D2, and a bent part 26 connecting the third passage part 25 and the second passage part 24. Since the depth D25 of the third passage part 25 is shallower than the depths D23, D24 of the first and second passage parts 23, 24, cross-sectional area S25 of the third passage part 25 is smaller than the cross-sectional areas S23, S24 of the first and second passage parts 23, 24. The bent part 26 includes a shallow region 26A extending from a position, corresponding to the side end 25r of the third passage part 25 in the first direction D1 toward the second passage part 24, and having a depth D26a shallower than that of the second passage part 24.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a heat sink.

  Patent Document 1 describes a heat sink for cooling a laser diode array. The heat sink is provided with a heat dissipating body in which a water channel through which cooling water flows is formed. In the water channel, a bend is formed in the region where the laser diode array is mounted, which causes turbulent flow of the cooling water. Thereby, the temperature distribution of the cooling water flowing in the water channel is made uniform.

  Patent Document 2 describes a cooling plate for cooling an electronic component. The cooling plate is made of a good heat conducting member having a flow passage through which the refrigerant flows. In the flow passage, a projecting member is provided on the inner wall of the portion facing the electronic component such that the cross-sectional area of the portion facing the surface of the electronic component is smaller than the cross-sectional area of the other portion.

Patent No. 3462598 Japanese Examined Patent Publication 7-70852

  As described above, in the case of a cooling member such as a heat sink, efficient cooling is achieved, such as causing turbulent flow in the refrigerant or partially reducing the cross-sectional area of the flow path. On the other hand, the inventors of the present invention have a problem that deterioration of members forming the flow path may be promoted in a portion where the flow paths having different cross-sectional areas are bent and connected. I found it.

  This invention is made in view of such a situation, and it aims at providing a heat sink which can control promotion of degradation, realizing efficient cooling.

  As a result of further investigations in consideration of the above problems, the inventors of the present invention have found that the flow of the refrigerant in the bending direction is in the portion where the flow paths having different cross-sectional areas are bent and connected. An unintended turbulent flow caused by the flow of the refrigerant in a plurality of directions, such as the flow of the refrigerant in the direction in which the cross-sectional area is expanded We came to find that deterioration is promoted. The present invention has been made based on such findings.

  That is, the heat sink according to the present invention is a heat sink for cooling a semiconductor laser device, and a main surface extending in a first direction and a second direction intersecting the first direction, and a refrigerant flow path through which a refrigerant flows And the main surface includes a mounting area on which the semiconductor laser device is mounted as viewed from a third direction intersecting the first direction and the second direction, and the refrigerant flow path is an introduction portion into which the refrigerant is introduced A lead-out portion from which the refrigerant is drawn, a first flow-path portion extending from the introduction portion to the placement area along the first direction, and the placement area to the lead-out portion along the first direction And a third flow passage extending in the second direction from the first flow passage to the second flow passage at a position overlapping the mounting area as viewed from the third direction. An end portion of the third flow passage portion in the second direction and a second flow in the first direction The third flow path portion has a cross-sectional area such that the depth of the third flow path portion in the third direction is the first flow path portion in the third direction; By making the depth smaller than the depth of the second flow path portion, the cross-sectional area of the first flow path portion and the second flow path portion is made smaller, and the bent portion is an end portion of the third flow path portion in the first direction. And a shallow region having a depth in the third direction which is shallower than the second flow passage portion.

  The heat sink has a main surface including a mounting area on which the semiconductor laser element to be cooled is mounted, and a coolant channel. The refrigerant flow path includes a first flow path portion and a second flow path portion extending along the first direction, and a third flow extending along the second direction from the first flow path portion toward the second flow path portion. It includes a passage portion and a bent portion connecting the second flow passage portion and the third flow passage portion. The first flow path portion is connected to the refrigerant introduction portion, and the second flow path portion is connected to the refrigerant discharge portion. Therefore, here, the refrigerant flows in the order of the first channel portion, the third channel portion, the bending portion, and the second channel portion.

  In particular, the third channel portion is provided at a position overlapping the mounting area, and is relatively shallow and has a small cross-sectional area. Therefore, the flow velocity of the refrigerant is increased when flowing through the third flow path portion, and efficient cooling in the mounting area is realized. Here, the bending portion connecting the second flow path portion and the third flow path portion extends from the position corresponding to the end portion of the third flow path portion in the first direction toward the second flow path portion, and is relatively Including shallow shallow regions. For this reason, the refrigerant flowing through the third flow passage portion is bent at least partially in the shallow portion region and flows, and then reaches the second flow passage portion having a relatively large cross-sectional area relatively deep. Therefore, in the bending portion, the flow of the refrigerant in the bending direction and the flow of the refrigerant in the depth direction (third direction) are less likely to be mixed, and the generation of the turbulent flow is suppressed. As a result, it is possible to suppress the promotion of deterioration in the bent portion.

  In the heat sink according to the present invention, the width of the shallow region in the first direction may be equal to or less than the width of the third flow passage in the first direction. By setting the width of the shallow region in this manner, the occurrence of turbulent flow can be sufficiently suppressed and acceleration of deterioration can be suppressed.

  In the heat sink according to the present invention, the width of the shallow region in the first direction may be 1/2 or more and 2/3 or less of the width of the third flow passage portion in the first direction. In this case, the pressure loss can be suppressed as compared with the case where the width of the shallow region is equal to the width of the third flow passage.

  In the heat sink according to the present invention, the gradual increase region in which the depth in the third direction gradually increases toward the opposite direction to the first direction is provided between the shallow region and the second flow passage portion. Good. In this case, the occurrence of turbulent flow can be more reliably suppressed in the depth direction (third direction).

  In the heat sink according to the present invention, the end of the bent portion may be formed in a curved shape. Also in this case, the occurrence of turbulent flow can be suppressed more reliably. Moreover, deterioration can be directly suppressed by suppressing a sudden change in the flow direction of the refrigerant.

  According to the present invention, it is possible to provide a heat sink capable of suppressing the promotion of deterioration while realizing efficient cooling.

It is a perspective view showing a semiconductor laser device concerning this embodiment. It is a schematic sectional drawing along the II-II line of FIG. It is a figure which shows the heat sink shown by FIG. FIG. 4 is a view showing a refrigerant flow path shown in FIG. 3; It is a figure which shows the refrigerant | coolant flow path which concerns on a modification. It is a figure which shows the refrigerant | coolant flow path which concerns on another modification. It is a figure which shows the refrigerant | coolant flow path which concerns on another modification.

  Hereinafter, an embodiment of a semiconductor laser device will be described with reference to the drawings. In the description of the drawings, the same elements or corresponding elements may be denoted by the same reference numerals and redundant description may be omitted. In each drawing, a first direction D1, a second direction D2 intersecting (for example, orthogonal) to the first direction, and a third direction D3 intersecting (for example, orthogonal) to the first direction D1 and the second direction D2. Note the coordinate system S shown.

  FIG. 1 is a perspective view showing a semiconductor laser device according to the present embodiment. FIG. 2 is a schematic cross-sectional view along the line II-II of FIG. As shown in FIGS. 1 and 2, the semiconductor laser device 1 includes a heat sink 2, a substrate 3, and a laser unit 4. The laser unit 4 includes a pair of submounts 5 and a semiconductor laser bar (semiconductor laser element) 6 disposed between the submounts 5. The substrate 3 is stacked on the heat sink 2 along the third direction D3 via the insulating layer 7. The substrate 3 is made of metal such as copper.

  The insulating layer 7 is formed in a plate shape of a material having heat conductivity and electrical insulation such as aluminum nitride (AlN), for example. Examples of other materials for forming the insulating layer 7 include silicon carbide (SiC) and diamond. A metallized layer is formed (metallized) on both sides of the insulating layer 7 in order to bond the heat sink 2 to the substrate 3. The surface on the heat sink 2 side of the substrate 3 is bonded to the heat sink 2 via the insulating layer 7 over the entire surface. For bonding between the heat sink 2 and the insulating layer 7, for example, indium (In) solder, SnAgCu solder, or the like is used from the viewpoint of lead-free.

  The metallized layer is formed of, for example, four metal layers of titanium (Ti) / copper (Cu) / nickel (Ni) / gold (Au) stacked sequentially from the surface side of the insulating layer 7. The metallization layer is formed, for example, by vapor deposition. The thicknesses of the metallization layers are equal to each other on both sides of the insulating layer 7. Warpage resulting from the formation of the metallized layer can be suppressed.

  The laser unit 4 is disposed on the substrate 3. The submount 5 is formed in a plate shape from a material having thermal conductivity and electrical conductivity such as copper tungsten (CuW), for example. Other constituent materials of the submount 5 include aluminum nitride (AlN), silicon carbide (SiC), tungsten (W), copper-molybdenum (MoCu) composite material, copper-diamond composite material and the like. On the surface of the submount 5, two plating layers of nickel (Ni) / gold (Au) or three plating layers of chromium (Cr) / platinum (Pt) / gold (Au) are formed. It is also good. Each submount 5 is soldered to the substrate 3. For example, indium (In) solder is used to bond each submount 5 to the substrate 3.

  The semiconductor laser bar 6 has, for example, a plate shape. The front end surface of the semiconductor laser bar 6 is an emission end surface having a plurality of light emitting regions. The semiconductor laser bar 6 is bonded to the submount 5. For bonding the semiconductor laser bar 6 and the submount 5, a solder having a melting point higher than that of the solder used for bonding the heat sink 2 and the substrate 3 is used. Examples of such solder include gold-tin solder.

  The semiconductor laser bar 6 has a substrate made of a compound semiconductor, the active layer is located at a position corresponding to the light emitting region, and the cladding layers are located on both sides of the active layer. Materials for the substrate include gallium arsenide (GaAs), gallium nitride (GaN), aluminum gallium arsenide (AlGaAs), gallium phosphide (GaP), aluminum gallium nitride (AlGaN), indium phosphide (InP), etc. Be In the present embodiment, for example, the main component of the substrate is gallium arsenide (GaAs). The active layer contains indium (In) in addition to gallium arsenide, and the cladding layer contains aluminum (Al) in addition to gallium arsenide.

  When driving the semiconductor laser device 1 as described above, a driving voltage is applied to the substrate 3 connected to the submount 5. As a result, a drive current is supplied to the semiconductor laser bar 6, and laser beams are respectively oscillated from the plurality of light emitting areas of the emitting end face. Heat generated by the semiconductor laser bar 6 at the time of laser oscillation is transmitted from the submount 5 to the substrate 3 and dissipated to the heat sink 2 side. That is, the semiconductor laser bar 6 is thermally connected to the heat sink 2 via one submount 5, the substrate 3 and the insulating layer 7 so that the heat generated at the time of laser oscillation is released via the heat sink 2 It has become.

  Subsequently, an embodiment of the heat sink shown in FIGS. 1 and 2 will be described. FIG. 3 is a diagram showing the heat sink shown in FIGS. (A) of FIG. 3 is a plan view, and (b) of FIG. 3 is a cross-sectional view taken along the line III-III of (a). FIG. 4 is a view showing the refrigerant flow path shown in FIG. (A) of FIG. 4 is a perspective view and (b) is a plan view. The heat sink 2 shown in FIGS. 3 and 4 is formed in a thick rectangular plate shape by a material having high heat conductivity such as a metal such as copper. The heat sink 2 is for cooling the semiconductor laser bar 6 as described above. The heat sink 2 has a rectangular main surface 2s extending along the first direction D1 and the second direction D2.

  The main surface 2s includes a mounting area 2a in which the semiconductor laser bar 6 (laser unit 4) is mounted as viewed in the third direction D3. The mounting area 2a is, for example, a rectangular area overlapping the semiconductor laser bar 6 along the third direction D3.

  The heat sink 2 is formed with a refrigerant flow path 20 through which a refrigerant (for example, a coolant such as water) flows. The refrigerant flow path 20 is formed to be bent in a U-shape as a whole as viewed in the third direction D3. Specifically, the refrigerant flow path 20 includes the introduction portion 21, the discharge portion 22, the first flow path portion 23, the second flow path portion 24, the third flow path portion 25, and the bending portion 26. The first flow passage portion 23, the second flow passage portion 24, and the third flow passage portion 25 have a rectangular parallelepiped shape. The introduction unit 21 introduces the refrigerant into the refrigerant flow path 20 (the refrigerant is introduced from the introduction unit 21). The lead-out unit 22 leads the refrigerant from the refrigerant flow passage 20 (the refrigerant is led from the lead-out unit 22).

  The first flow passage portion 23 extends from the introduction portion 21 toward the placement area 2 a along the first direction D1. The first flow passage portion 23 is connected to the introduction portion 21 at one end portion 23a, and is connected to the third flow passage portion 25 at the other end portion 23b. The first flow passage portion 23 has a depth D23 in the third direction D3 and has a cross-sectional area S23 in a cross section intersecting (orthogonal to) the first direction D1.

  The second flow passage portion 24 extends from the placement area 2a to the lead-out portion 22 along the first direction D1. The second flow passage portion 24 is connected to the bending portion 26 at one end 24 a and connected to the lead-out portion 22 at the other end 24 b. The second flow passage portion 24 has a depth D24 in the third direction D3 and has a cross-sectional area S24 in a cross section intersecting (orthogonal to) the first direction D1. Here, as an example, the depth D23 and the depth D24 are substantially the same as each other, and the cross-sectional area S23 and the cross-sectional area S24 are substantially the same as each other.

  The third flow passage portion 25 extends along the second direction D2 from the first flow passage portion 23 toward the second flow passage portion 24 in the vicinity of the main surface 2s. The third flow passage portion 25 is positioned so as to overlap the placement area 2a as viewed in the third direction D3. In other words, the third flow passage 25 is located directly below the laser unit 4 (semiconductor laser bar 6). The third flow passage 25 is connected to the other end 23b of the first flow passage 23 at one end 25a, and is connected to the bending portion 26 at the other end 25b.

  When viewed from the third direction D3, the first flow passage portion 23 reaches the position corresponding to the side end 25r of the third flow passage portion 25 in the first direction (that is, the end of the refrigerant flow passage 20 in the first direction Extends to the On the other hand, the second flow passage 24 does not reach the position corresponding to the side end 25 r of the third flow passage 25 as viewed from the third direction D 3, and is opposite to the side end 25 r of the third flow passage 25. It remains at the position corresponding to the side end 25p (that is, it does not reach the end of the refrigerant flow passage 20 in the first direction D1). Thereby, the one end 24 a of the second flow passage 24 and the other end 25 b of the third flow passage 25 are separated from each other. The bending portion 26 connects the second flow path portion 24 and the third flow path portion 25 to each other by connecting the one end portion 24 a and the other end portion 25 b.

  The third flow path unit 25 has a depth D25 in the third direction D3 and a cross-sectional area S25 in a cross section intersecting (orthogonal to) the second direction D2. The cross-sectional area S25 of the third flow passage 25 is smaller than the cross-sectional areas S23 and S24 because the depth D25 is smaller than the depths D23 and D24. However, the width W25 of the third flow passage 25 in the first direction is the second flow passage 23 and the second flow passage 24 in a range in which the cross-sectional area S25 is smaller than the cross-sectional areas S23 and S24. It may be larger than the width of the direction.

  Here, the depth of the bending portion 26 in the third direction D3 changes along the second direction D2 (here, in two steps). That is, the bending portion 26 has a depth D26a in the third direction D3 and another depth D26b in the third direction D3. The depth D26a is smaller than the depth D26b. Here, the depth D26b is substantially the same as the depth D24. Thus, the bending portion 26 includes the shallow region 26A in which the depth (the depth D26a) in the third direction D3 is shallower than the second flow passage portion 24.

  The shallow region 26A extends from the position corresponding to the side end 25r of the third flow passage 25 in the first direction D1 toward the second flow passage 24. The shallow region 26A reaches a position corresponding to the side end 24r of the second flow passage 24 in the second direction D2 (that is, reaches the end of the refrigerant flow passage 20 in the second direction D2). The width W26A of the shallow region 26A in the first direction D1 is equal to or less than the width (the width W25 or less) of the third flow passage portion 25 in the first direction D1. Here, the width W26A is 1⁄2 or more and 2/3 or less of the width W25, and is about 1⁄2 as an example.

  In the refrigerant flow passage 20 as described above, the refrigerant introduced from the introduction portion 21 first flows from the one end 23a of the first flow passage 23 toward the other end 23b in the first direction D1. The refrigerant reaching the other end 23 b of the first flow passage 23 flows into the third flow passage 25 while bending in the second direction D 2, and flows from the one end 25 a of the third flow passage 25 to the other end It distributes in the second direction D2 toward the unit 25b. At this time, the flow velocity of the refrigerant is increased according to the reduction of the cross-sectional area. The refrigerant reaching the other end 25 b of the third flow passage 25 is bent in the direction opposite to the first direction D 1 in the process of flowing through the bending portion 26 and flows into the second flow passage 24.

  At this time, since the shallow state is maintained from the third flow path 25 to the shallow region 26A of the bending portion 26, the refrigerant flowing through at least the shallow region 26A has a depth direction (third direction D3 Bending in the opposite direction of the first direction D1 in a state where no flow to the Thereafter, with respect to the refrigerant that has passed through the shallow region 26A, a flow in the depth direction occurs when traveling toward the second flow passage portion 24. The refrigerant having flowed into the second flow passage 24 flows from the one end 24a to the other end 24b of the second flow passage 24 in the direction opposite to the first direction D1 and reaches the outlet 22 and from the outlet 22 It is derived.

  As described above, the heat sink 2 has the main surface 2s including the mounting area 2a on which the semiconductor laser bar 6 to be cooled is mounted, and the refrigerant flow path 20. The refrigerant flow path 20 extends in the first direction D1 such that the first flow path portion 23 and the second flow path portion 24 extend from the first flow path portion 23 toward the second flow path portion 24 in the second direction D2. And a bent portion 26 connecting the second flow path portion 24 and the third flow path portion 25. The first flow passage portion 23 is connected to the introduction portion 21 of the refrigerant, and the second flow passage portion 24 is connected to the discharge portion 22 of the refrigerant. Therefore, in this case, the refrigerant flows in the order of the first flow passage portion 23, the third flow passage portion 25, the bending portion 26, and the second flow passage portion 24.

  In particular, the third flow passage portion 25 is provided at a position overlapping with the placement area 2a, and is relatively shallow and has a small cross-sectional area. For this reason, the flow velocity of the refrigerant is increased when flowing through the third flow passage portion 25, and efficient cooling in the placement area 2a is realized. Here, the bent portion 26 connecting the second flow passage portion 24 and the third flow passage portion 25 is the second flow passage from the position corresponding to the side end 25 r of the third flow passage portion 25 in the first direction D1. It extends towards the portion 24 and includes a relatively shallow shallow region 26A. For this reason, the refrigerant flowing through the third flow passage portion 25 is bent at least partially in the shallow region 26A and flows, and then reaches the second flow passage portion 24 which is relatively deep and has a large cross-sectional area. Therefore, in the bending portion 26, the flow of the refrigerant in the bending direction and the flow of the refrigerant in the depth direction (the third direction D3) are not easily mixed, and the generation of the turbulent flow is suppressed. As a result, acceleration of deterioration can be suppressed in the bent portion 26.

  In the heat sink 2, the width W26A of the shallow region 26A in the first direction D1 is equal to or less than the width W25 of the third flow passage 25 in the first direction D1. By setting the width W26A of the shallow region 26A in this manner, the occurrence of turbulent flow can be sufficiently suppressed and acceleration of deterioration can be suppressed.

  In particular, in the heat sink 2, the width W26A of the shallow region 26A in the first direction D1 is 1/2 or more and 2/3 or less of the width W25 of the third flow passage 25 in the first direction D1. For this reason, compared with the case where width W26A of shallow part field 26A is equivalent to width W25 of the 3rd channel part 25, pressure loss is controlled.

  The above embodiment describes an example of the heat sink according to the present invention. Therefore, the heat sink according to the present invention can be obtained by arbitrarily changing the heat sink 2 described above.

  Subsequently, a modification of the refrigerant flow passage 20 in the heat sink 2 will be described. FIG. 5 is a view showing a refrigerant flow path according to a modification. (A) of FIG. 5 is a perspective view, and (b) is a plan view. As in the example shown in FIG. 5, in the refrigerant flow passage 20, the width W26A of the shallow region 26A in the first direction D1 is substantially the same as the width W25 of the third flow passage 25 in the first direction D1. It may be In this case, the whole of the bending portion 26 becomes the shallow region 26A. According to such a configuration, since the flow in the depth direction (the third direction D3) does not occur when the refrigerant bends and flows in the bending portion 26, the generation of the turbulent flow can be more reliably suppressed.

  FIG. 6 is a view showing a refrigerant flow path according to another modification. (A) of FIG. 6 is a perspective view, and (b) is a plan view. As in the example shown in FIG. 6, in the refrigerant flow passage 20, the depth in the third direction D3 is directed between the shallow region 26A and the second flow passage portion 24 in the direction opposite to the first direction D1. The gradual increase area 26B where the gradual increase gradually is provided, in this case, the depth D26b of the gradual increase area 26B in the third direction D3 is the depth D24a of the second flow passage portion 24 from the depth D26a of the shallow area 26A. Although it increases gradually at a constant rate (ie, linearly), it may increase gradually. When the gradually increasing region 26B is provided as described above, the occurrence of turbulent flow can be more reliably suppressed in the depth direction (third direction).

  FIG. 7 is a view showing a refrigerant flow path according to still another modification. (A) of FIG. 7 is a perspective view, and (b) is a side view. In the example shown in FIG. 7, the end of the bending portion 26 is chamfered in a curved shape. More specifically, in the bending portion 26, the edge 26r of the shallow region 26A is chamfered in a partial cylindrical shape, and the boundary between the shallow region 26A and the gradual increase region 26B is a partial cylinder. It is flat. In this case, the occurrence of turbulent flow can be suppressed more reliably. Furthermore, in this case, deterioration can be directly suppressed by suppressing a sudden change in the flow direction of the refrigerant.

  DESCRIPTION OF SYMBOLS 2 ... Heat sink, 2a ... mounting area, 2s ... principal surface, 6 ... Semiconductor laser bar (semiconductor laser element), 20 ... Refrigerant flow path, 21 ... Introduction part, 22 ... Derivation part, 23 ... 1st flow path part, 24 ... 2nd channel part, 25 ... 3rd channel part, 26 ... bent part, 26A ... shallow part area, 26B ... gradually increasing area.

Claims (5)

A heat sink for cooling a semiconductor laser device;
A major surface extending along a first direction and a second direction intersecting the first direction;
A refrigerant flow path through which the refrigerant flows;
The main surface includes a mounting area on which the semiconductor laser device is mounted when viewed from a third direction intersecting the first direction and the second direction,
The refrigerant flow path is a first flow path portion that extends from the introduction portion toward the placement area along the first direction from the introduction portion into which the refrigerant is introduced, the discharge portion from which the refrigerant is drawn, and the first direction And a second flow passage portion extending from the placement area to the lead-out portion along the first direction, and the first flow passage portion at a position overlapping the placement area as viewed from the third direction A third flow passage extending along the second direction from the second flow direction toward the second flow passage, an end of the third flow passage in the second direction, and the second flow in the first direction And a bend connecting the end of the passage,
Regarding the cross-sectional area of the third flow passage portion, the depth of the third flow passage portion in the third direction is greater than the depths of the first flow passage portion and the second flow passage portion in the third direction. By being shallow, the cross-sectional area of the first flow path portion and the second flow path portion is made smaller,
The bent portion extends from a position corresponding to an end of the third flow passage in the first direction toward the second flow passage, and the depth in the third direction is the second flow passage Including shallower regions that are shallower than
heatsink. The width of the shallow region in the first direction is equal to or less than the width of the third flow passage in the first direction.
The heat sink according to claim 1. The width of the shallow region in the first direction is not less than 1/2 and not more than 2/3 of the width of the third flow passage in the first direction.
The heat sink according to claim 2. A gradually increasing region is provided between the shallow region and the second flow passage portion, in which the depth in the third direction gradually increases in the direction opposite to the first direction.
The heat sink as described in any one of Claims 1-3. The end of the bent portion is formed in a curved shape.
The heat sink as described in any one of Claims 1-4.

Images