200850137 九、發明說明 【發明所屬之技術領域】 本發明係關於用來冷卻複數個發熱體（特別是PC的 發熱源）之液冷系統。 【先前技術】 最近的筆gH型電腦’除CPU以外，還具有GPU、晶 片組等複數個發熱體’如何有效冷卻這些發熱體乃技術課 題所在。在零件的收納空間受限之筆記型電腦，係要求整 體呈薄型且具有高單元性之液冷系統。 〔專利文獻1〕日本特開2002-261223號公報 〔專利文獻2〕日本特開2 0 0 4 - 3 8 1 6號公報 〔專利文獻3〕日本特開2004-266247號公報 【發明內容】 習知技術，是對每個發熱源都設置泵、吸熱部、散熱 部（散熱器）、冷卻風扇，其中之散熱器和冷卻風扇是成 對設置。因此，隨著發熱源的數目增多會變得大型化’而 造成問題。又即使只有單一發熱源，當其發熱量大時’必 須使用大型的散熱器和冷卻風扇。 本發明之目的是爲了提供一種小型的液冷系統’即使 存在複數個發熱體或發熱體爲單一個但發熱量大時’仍能 進行高效率的散熱。 本發明所著眼的觀點在於，散熱器的數目較佳爲發熱 -4- 200850137 源的數目之同數以上，相對於此，冷卻風扇不一定要對應 於散熱器來設置，只要其數目比散熱器少，即可獲得小型 且局效率的液冷系統。 亦即，本發明之液冷系統，係具備：與發熱源形成熱 接觸以吸走該發熱源的熱之受熱板、散熱器、用來讓冷媒 循環於受熱板和散熱器之間的泵、用來對散熱器供應冷卻 風的冷卻風扇而構成之液冷系統，其特徵在於：設置複數 個流路獨立的散熱器，且設置數目比該等散熱器的數目更 少之用來對該等散熱器供應冷卻風的冷卻風扇。 散熱器一般而言，可對應於各發熱源及受熱板來設置 〇 又當發熱源爲單一且其產生熱量較大時，可將複數個 散熱器連接於該發熱源的受熱板。 若冷卻風扇爲多葉風扇（sirocco fan)，則容易在其 周圍配置複數個散熱器。 另一方面，即使散熱器爲複數個，泵仍可維持單一個 。泵可使用能抑制壓力損失造成的流量減低之壓電泵。 較佳爲在散熱器設置：單一的入口部、出口部、以及 兩端部連通於該入口部和出口部之複數個積層流路板。藉 由讓來自冷卻風扇的冷卻風通過各積層流路板間所形成的 空氣流通間隙，可將冷媒施予冷卻。積層流路板的數目’ 可按照發熱源的發生熱量（各散熱器的負擔冷卻熱量）來 進行增減。 採用這種散熱器構造時，若將複數個散熱器所使用之 -5- 200850137 積層流路板配置於相同位置，將容易對複數個散熱器配置 單一的冷卻風扇。 可在各積層流路板設置至少進行1次U字狀彎折的 液體流路。 本發明之液冷系統，比起用來散出發熱源的熱之散熱 器，由於用來對該散熱器供給冷卻風之冷卻風扇的數目少 ，故可獲得小型的液冷系統。 【實施方式】 第1圖至第4圖係顯示本發明的液冷系統之實施形態 之配置槪念圖。第1圖的實施形態，係用來冷卻2個發熱 源（例如筆記型PC之CPU和GPU) 11、12之水冷系統 。從單一泵20流出的冷媒，首先通過與發熱源1 1形成熱 接觸之受熱板1 3的液體流路1 3 a將該發熱源1 1的熱吸走 後，到達第1散熱器3 1。流過第1散熱器3 1的液體流路 31f之冷媒，通過與發熱源12形成熱接觸之受熱板14的 液體流路1 4a將該發熱源1 2的熱吸走後’到達第2散熱 器32。流過該散熱器32的液體流路32f之冷媒會返回泵 2 0。受熱板1 3、1 4是由傳熱性優異的金屬材料（例如鋁 合金）構成，可將發熱源1 1、12所產生的熱傳送給流過 液體流路1 3 a、1 4 a的冷媒。這種受熱板是周知的。 2個散熱器3 1、3 2呈並列配置，對這2個散熱器3 1 、32設有共通（單一）的冷卻風扇41。冷卻風扇41和散 熱器31、32各個的距離相同。 -6 - 200850137 第2圖的實施形態中，散熱器3 1、3 2的配置位置不 同。圖中雖繪製成，相對於冷卻風扇41的送風方向’將 散熱器3 1、3 2前後配置，但可將散熱器3 1、3 2上下配置 (與第2圖的紙面垂直的方向之位置不同），而使冷卻風 扇4 1和散熱器3 1、3 2各個的距離相同。各實施形態之共 通點在於，對於2個散熱器3 1、3 2僅使用1個冷卻風扇 41 〇 第3圖的實施形態，是對於3個發熱源（例如筆記型 PC的CPU、GPU、晶片組的發熱源）1 1、12、15，使用3 個散熱器3 1、3 2、3 3，對於散熱器3 1、3 2使用共通的1 個冷卻風扇41，而對散熱器33使用獨立的冷卻風扇42。 在與發熱源1 5形成熱接觸之受熱板1 6，設置和其他受熱 板相同的液體流路1 6a，在散熱器3 3設置和其他散熱器 同樣的液體流路3 3 f。 第4圖的實施形態，是將本發明適用於··對i個發熱 源1 1連接3個散熱器3 1、3 2、3 3的態樣。在與發熱源 1 1形成熱接觸的受熱板1 7，形成有3個獨立的液體流路 17a、17b、17c。來自泵2〇的冷媒，通過受熱板17的液 體流路1 7 a而到達散熱器3 1的液體流路3 i f，從液體流路 3 1 f流出的冷媒，通過液體流路！ 7b後到達散熱器3 2的 液體流路32f。從液體流路32f流出的冷媒，通過受熱板 1 7的液體流路1 7 c而到達散熱器3 3的液體流路3 3 f，接 著返回泵20。對2個散熱器31、32使用1個冷卻風扇41 ，對1個散熱器3 3使用1個冷卻風扇42，這點是和第3 200850137 圖的實施形態相同。 第5圖係顯示對1個冷卻風扇配置複數個散熱器之較 佳配置例。冷卻風扇4 1，係由可將從軸部吸收的空氣朝 周圍360°排出的多葉風扇41S所構成，在該多葉風扇41S 的周圍配置散熱器3 1、3 2、3 3。也能配置更多的散熱器 〇 如以上實施形態所說明，從單一泵20流出的冷卻在 受熱板（13、14、16、17 )的液體流路（13a、14a、16a 、：17a〜17c)和散熱器（31〜33)的液體流路（31f〜33f )循環後，再度返回泵2 0，如此能用有限的流量來傳送 更多的熱量，而能高效率地進行冷卻。在本實施形態，由 於冷卻風扇（4 1、42 )的數目比散熱器（3 1〜3 3 )的數目 更少，故能謀求小型化。 泵2 0可使用任何形式的泵，但本實施形態的液冷系 統是藉由1個泵20來使冷媒流過受熱板的複數個液體流 路13a、14a、16a、17a〜17c，因此較佳爲使用能抑制壓 力損失所造成的流量降低之壓電栗。第6圖、第7圖係顯 示壓電泵2 0 P的一實施形態。 該壓電泵20，由下至上依序設有下殼體21和上殼體 22。在下殼體21’以與該殼體之板厚平面正交的方式穿 設有互相平行的排出口 2 1 A和吸入口 2 1 B。在下殼體2 1 和上殻體22之間’透過〇型環23將壓電振動元件（隔 膜）24挾持支承成液密狀態’在該壓電振動元件24和下 殼體21之間構成泵室P。在壓電振動元件24和上殼體22 -8- 200850137 之間形成大氣室A。 壓電振動元件24，係具有中心部的薄片材（shim ) 24a、以及積層形成於薄片材24a的表裏其中一面（第7 圖的上面）之壓電體2 4b而構成之單壓電體型式。薄片材 2 4a係面向泵室p而和液體接觸。薄片材24a，係由導電 性金屬薄板材料，例如厚度5 0〜3 0 0 // m左右之不銹鋼、 42合金等所形成之金屬製薄板所構成。壓電體24b，例如 是由厚度300/zm左右之pzT(Pb(Zr、Ti)03)所構成， 在其表裏方向實施極化處理。這種壓電振動元件屬周知者 〇 在下殼體21之排出口 21A和吸入口 21B，分別設有 止回閥（傘形閥）25、26。止回閥 25，係容許流體從吸 入口 2 1 A流向泵室P但不容許與其逆向的流體流之吸入 側止回閥；止回閥26，係容許流體從泵室P流向排出口 2 1 B但不容許與其逆向的流體流之排出側止回閥。 止回閥25、26係採用同一形態，是在接合固定於流 路之穿孔基板25a、26a上，裝設彈性材料構成之傘形閥 25b、26b而成。這種止回閥（傘形閥）本身屬周知者。 以上的壓電泵20P，當壓電振動元件24朝正反方向 進行彈性變形（振動）時，在泵室P的容積擴大的行程， 由於吸入側止回閥2 5打開且排出側止回閥2 6關閉，故液 體會從吸入側21A流入泵室P內。另一方面，在泵室P 的容積縮小的行程，由於排出側止回閥26打開且吸入側 止回閥25關閉，液體會從泵室P朝排出口 21B流出。因 -9- 200850137 此，藉由使壓電振動元件24朝正反方 形（振動），可得到泵作用。 第8圖至第10圖係顯示散熱器31 態。複數個流路獨立的散熱器可形成單 的冷卻風扇來進行冷卻。圖示的實施形 段的散熱器3 1、3 2之串列散熱器3 0。 係由傳熱性良好的金屬材料（例如鋁合 方具有散熱器31用的入口部31a、出 (圖示例爲7片）的積層流路板3 1 c， 32用的入口部32a、出口部32b及複數 )的積層流路板32c。散熱器31、32， 圖所示之以區隔線D分割者相結合， 成一體。 如第9圖及第10圖所不，入口部 於入口側共通縱通路3 1 d ( 3 2d )，出[ 連接於出口側共通縱通路31e(32e) 3 lc ( 32c )內形成U字狀的液體流路3 部分別連通於入口側共通縱通路3 1 d ( 通縱通路31e(32e)。在各積層流路| 形成空氣流通間隙31g ( 32g)。對該_ 1個冷卻風扇41，來自冷卻風扇41的 流通間隙31g ( 32g)。 因此，從入口部3 1 a ( 3 2 a )流入 口側共通縱通路31d ( 32d )而流過各 向連續進行彈性變 〜3 3之較佳實施形 一單元，而用單一 態，是具有上下2 該串列散熱器3 0， 金）所構成，在上 口部3 1 b及複數個 在下方具有散熱器 個（圖示例爲7片 可將第8圖、第9 也能是最初就是形 31a ( 32a)是連接 ]部 3 1b ( 32b)是 。在各積層流路板 1 f ( 3 2 f )，其兩端 :3 2d )和出口側共 反3 1 c ( 3 2 c )之間 ;列散熱器3 0配置 冷卻風會流過空氣 的冷媒，會流入入 積層流路板3 1 c ( -10- 200850137 3 2 c )的液體流路3 1 f ( 3 2 f )。在各積層流路板3 1 c ( 3 2 c )之間，形成有讓冷卻風扇4 1的冷卻風流過之空氣流通 間隙3 1 g ( 3 2g )，藉此可將流過液體流路3 1 f ( 3 2f )間 的冷卻施以冷卻。接著，返回出口側共通縱通路3 1 e ( 32e)的冷媒，會從出口部31b ( 32b)排出，而到達下個 受熱板的液體流路或泵20。 【圖式簡單說明】 第1圖係本發明的液冷系統之一實施形態之系統連接 圖。 第2圖係本發明的液冷系統之另一實施形態之系統連 接圖。 第3圖係本發明的液冷系統之另一實施形態之系統連 接圖。 第4圖係本發明的液冷系統之另一實施形態之系統連 接圖。 第5圖係顯示多葉風扇和散熱器的配置形態例之俯視 圖。 第6圖係壓電泵單體的俯視圖。 第7圖係第6圖的VII_VII線之截面圖。 第8圖係串列散熱器單體的立體圖。 第9圖係第8圖的前視圖。 第10圖係第9圖的χ-χ線之截面圖。 -11 - 200850137 【主要元件符號說明】 1 1、1 2、1 5 :發熱源 13、 14、 16、 17:受熱板 13a、 14a、 16a、 17a、 17b、 17c ：液體流路 2 0 :壓電泵（泵） 2 1 :下殼體 22 :上殼體 24 :壓電振動元件（隔膜） -12-200850137 IX. Description of the Invention [Technical Field] The present invention relates to a liquid cooling system for cooling a plurality of heat generating bodies (particularly, a heat generating source of a PC). [Prior Art] Recently, the gH type computer has a plurality of heat generating bodies such as a GPU and a wafer set in addition to the CPU. How to effectively cool these heat generating bodies is a technical problem. A notebook computer with limited storage space for parts requires a liquid cooling system that is thin and highly unitary. [Patent Document 1] JP-A-2002-261223 (Patent Document 2) Japanese Laid-Open Patent Publication No. JP-A-2004-266247 (Patent Document 3) The technology is to provide a pump, a heat sink, a heat sink (heat sink), and a cooling fan for each heat source, wherein the heat sink and the cooling fan are arranged in pairs. Therefore, as the number of heat sources increases, it becomes larger, which causes problems. Even if there is only a single heat source, when it generates a large amount of heat, a large radiator and a cooling fan must be used. SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized liquid-cooling system which can efficiently dissipate heat even when a plurality of heating elements or heating elements are single, but when the amount of heat is large. The point of view of the present invention is that the number of heat sinks is preferably equal to or greater than the number of heat generations - 200850137 sources. In contrast, the cooling fans do not have to be arranged corresponding to the heat sinks, as long as the number of heat sinks is greater than the number of heat sinks. With less, a small, efficient liquid cooling system can be obtained. That is, the liquid cooling system of the present invention includes: a heat receiving plate that forms a thermal contact with a heat source to absorb the heat source, a heat sink, and a pump for circulating the refrigerant between the heat receiving plate and the heat sink, a liquid cooling system comprising a cooling fan for supplying a cooling air to a radiator, characterized in that a plurality of flow path independent heat sinks are disposed, and a number of the radiators are set to be smaller than the number of the heat sinks for the same The radiator supplies a cooling fan for cooling air. In general, the heat sink may be provided corresponding to each of the heat source and the heat receiving plate. When the heat source is single and the heat generation is large, a plurality of heat sinks may be connected to the heat receiving plate of the heat source. If the cooling fan is a sirocco fan, it is easy to arrange a plurality of heat sinks around it. On the other hand, even if the number of radiators is plural, the pump can maintain a single one. The pump can use a piezoelectric pump that suppresses the flow reduction caused by pressure loss. Preferably, the heat sink is provided with a single inlet portion, an outlet portion, and a plurality of laminated flow passage plates that communicate with the inlet portion and the outlet portion at both ends. The refrigerant can be cooled by allowing the cooling air from the cooling fan to pass through the air flow gap formed between the laminated plates. The number of laminated flow plates can be increased or decreased according to the amount of heat generated by the heat source (the heat of each radiator is used to cool the heat). In the case of such a heat sink structure, if the -5-200850137 laminated flow path plates used in a plurality of heat sinks are disposed at the same position, it is easy to arrange a single cooling fan for a plurality of heat sinks. A liquid flow path in which at least one U-shaped bending is performed can be provided on each of the laminated flow path plates. The liquid cooling system of the present invention can obtain a small liquid cooling system because the number of cooling fans for supplying cooling air to the radiator is small compared to the heat radiator for dissipating the heat source. [Embodiment] Figs. 1 to 4 are views showing a configuration of an embodiment of a liquid cooling system of the present invention. The embodiment of Fig. 1 is a water cooling system for cooling two heat sources (e.g., CPU and GPU of a notebook PC) 11, 12. The refrigerant that has flowed out of the single pump 20 first absorbs the heat of the heat source 1 1 through the liquid flow path 1 3 a of the heat receiving plate 13 that is in thermal contact with the heat source 1 1 and then reaches the first heat sink 31. The refrigerant flowing through the liquid flow path 31f of the first heat sink 31 is sucked away by the heat flow of the heat source 12 by the liquid flow path 14a of the heat receiving plate 14 which is in thermal contact with the heat source 12, and reaches the second heat dissipation. 32. The refrigerant flowing through the liquid flow path 32f of the radiator 32 is returned to the pump 20. The heat receiving plates 13 and 14 are made of a metal material (for example, an aluminum alloy) having excellent heat conductivity, and heat generated by the heat sources 1 1 and 12 can be transmitted to the liquid flow paths 1 3 a and 14 a. Refrigerant. Such heated plates are well known. The two heat sinks 3 1 and 3 2 are arranged in parallel, and a common (single) cooling fan 41 is provided to the two heat sinks 3 1 and 32 . The distance between the cooling fan 41 and the heat radiators 31, 32 is the same. -6 - 200850137 In the embodiment of Fig. 2, the arrangement positions of the heat sinks 3 1 and 3 2 are different. In the figure, the heat sinks 3 1 and 3 2 are arranged in front and rear with respect to the air blowing direction of the cooling fan 41. However, the heat sinks 3 1 and 3 2 can be arranged vertically (in a direction perpendicular to the paper surface of FIG. 2). Differently, the distance between the cooling fan 4 1 and the heat sinks 3 1 , 3 2 is the same. The common point of each embodiment is that only one cooling fan 41 is used for the two heat sinks 3 1 and 3 2 . The embodiment of Fig. 3 is for three heat sources (for example, CPU, GPU, and chip of a notebook PC). Group of heat sources) 1 1, 12, 15, using 3 heat sinks 3 1 , 3 2, 3 3, using a common cooling fan 41 for the heat sinks 3 1 and 3 2, and using the heat sink 33 independently Cooling fan 42. The heat receiving plate 16 which is in thermal contact with the heat source 15 is provided with the same liquid flow path 16a as the other heat receiving plates, and the heat sink 33 is provided with the same liquid flow path 3 3f as the other heat sinks. In the embodiment of Fig. 4, the present invention is applied to the case where three heat sinks 3 1 , 3 2 , and 3 3 are connected to i heat source 1 1 . The heat receiving plates 177 which are in thermal contact with the heat source 1 1 are formed with three independent liquid flow paths 17a, 17b, 17c. The refrigerant from the pump 2 passes through the liquid flow path 17 7 a of the heat receiving plate 17 to reach the liquid flow path 3 i f of the radiator 3 1 , and the refrigerant flowing out from the liquid flow path 3 1 f passes through the liquid flow path! After 7b, the liquid flow path 32f of the radiator 3 2 is reached. The refrigerant flowing out of the liquid flow path 32f passes through the liquid flow path 1 7 c of the heat receiving plate 17 to reach the liquid flow path 3 3 f of the radiator 3 3, and is connected to the return pump 20. One cooling fan 41 is used for the two heat sinks 31 and 32, and one cooling fan 42 is used for one heat sink 33. This is the same as the embodiment of the third 200850137. Fig. 5 is a view showing a preferred arrangement of a plurality of heat sinks for one cooling fan. The cooling fan 41 is composed of a multi-blade fan 41S that can discharge air absorbed from the shaft portion 360° around the circumference, and the radiators 3 1 , 3 2, and 3 3 are disposed around the multi-blade fan 41S. It is also possible to arrange more radiators, as explained in the above embodiment, the liquid flow paths (13a, 14a, 16a, 17a to 17c) which are cooled from the single pump 20 and are cooled by the heat receiving plates (13, 14, 16, 17). After circulating the liquid flow paths (31f to 33f) of the radiators (31 to 33), the pump 20 is returned again, so that more heat can be transferred with a limited flow rate, and cooling can be performed efficiently. In the present embodiment, since the number of the cooling fans (4 1 and 42 ) is smaller than the number of the heat sinks (3 1 to 3 3 ), the size can be reduced. The pump 20 can use any type of pump, but the liquid cooling system of the present embodiment uses a single pump 20 to allow the refrigerant to flow through the plurality of liquid flow paths 13a, 14a, 16a, 17a to 17c of the heat receiving plate. It is good to use a piezoelectric pump that can suppress the flow loss caused by pressure loss. Fig. 6 and Fig. 7 show an embodiment of the piezoelectric pump 20 P. The piezoelectric pump 20 is provided with a lower casing 21 and an upper casing 22 in this order from bottom to top. The lower casing 21' is provided with discharge ports 2 1 A and suction ports 2 1 B which are parallel to each other so as to be orthogonal to the plane of the plate thickness of the casing. The piezoelectric vibration element (diaphragm) 24 is held in a liquid-tight state through the 〇-shaped ring 23 between the lower casing 2 1 and the upper casing 22, and a pump is formed between the piezoelectric vibration element 24 and the lower casing 21 Room P. An atmospheric chamber A is formed between the piezoelectric vibration element 24 and the upper casing 22 -8 - 200850137. The piezoelectric vibration element 24 is a single piezoelectric material type having a central portion of a shim 24a and a piezoelectric body 24b formed by laminating one surface (the upper surface of the seventh figure) of the sheet 24a. . The sheet member 2 4a faces the pump chamber p and comes into contact with the liquid. The sheet material 24a is made of a metal thin plate made of a conductive metal thin plate material, for example, stainless steel or 42 alloy having a thickness of about 50 to 300 m / m. The piezoelectric body 24b is made of, for example, pzT (Pb(Zr, Ti)03) having a thickness of about 300/zm, and is subjected to polarization treatment in the front and back directions. Such a piezoelectric vibration element is well known. 排 The discharge port 21A and the suction port 21B of the lower casing 21 are provided with check valves (umbrella valves) 25 and 26, respectively. The check valve 25 is a suction side check valve that allows fluid to flow from the suction port 21 A to the pump chamber P but does not allow reverse flow of the fluid; the check valve 26 allows fluid to flow from the pump chamber P to the discharge port 2 1 B, but does not allow the discharge side check valve of the fluid flow opposite thereto. In the same manner, the check valves 25 and 26 are formed by attaching the umbrella valves 25b and 26b made of an elastic material to the perforated substrates 25a and 26a fixed to the flow path. Such a check valve (umbrella valve) is known per se. In the piezoelectric pump 20P described above, when the piezoelectric vibration element 24 is elastically deformed (vibrated) in the forward and reverse directions, the stroke of the pump chamber P is expanded, and the suction side check valve 25 is opened and the discharge side check valve is opened. 2 6 is closed, so liquid flows into the pump chamber P from the suction side 21A. On the other hand, in the stroke in which the volume of the pump chamber P is reduced, since the discharge side check valve 26 is opened and the suction side check valve 25 is closed, the liquid flows out from the pump chamber P toward the discharge port 21B. According to -9-200850137, the pumping action can be obtained by making the piezoelectric vibration element 24 face-and-reverse (vibration). Figures 8 through 10 show the state of the heat sink 31. A plurality of independent heat sinks can form a single cooling fan for cooling. The heat sinks 3 1 and 3 2 of the illustrated embodiment are arranged in series with the heat sink 30. A metal material having good heat conductivity (for example, an inlet portion 32a for the laminated flow path plates 3 1 c, 32 for the inlet portion 31a for the radiator 31 and the outlet portion 31a for the radiator 31) The laminated flow channel plate 32c of the portion 32b and the plural). The heat sinks 31, 32, as shown in the figure, are combined by the partition D to form an integral body. As shown in Fig. 9 and Fig. 10, the inlet portion has a vertical passage 3 1 d ( 3 2d ) on the inlet side, and a U-shaped portion is formed in the common longitudinal passage 31e (32e) 3 lc ( 32c ) connected to the outlet side. The liquid flow path 3 is connected to the inlet-side common vertical passage 3 1 d (the longitudinal passage 31e (32e). The air flow gap 31g (32g) is formed in each of the laminated flow paths. For the one cooling fan 41, The flow gap 31g (32g) from the cooling fan 41. Therefore, from the inlet portion 3 1 a ( 3 2 a ) to the inlet side common longitudinal passage 31d (32d), it is preferable to continuously change the elastic direction to the third direction. A unit is formed, and in a single state, it is composed of upper and lower two series of heat sinks 30, gold, and has a heat sink at the upper mouth portion 3 1 b and a plurality of lower ones (illustration is 7 pieces) The figure 8 and the ninth can be the first shape 31a (32a) is the connection portion 3 1b ( 32b). In each of the laminated flow path plates 1 f ( 3 2 f ), both ends thereof: 3 2d ) And the outlet side is opposite to 3 1 c ( 3 2 c ); the column radiator 30 is configured with a cooling air that flows through the air and flows into the laminar flow path plate 3 1 c ( -10- 200850137 3 2 c ) of Fluid flow passage 3 1 f (3 2 f). Between each of the laminar flow path plates 3 1 c ( 3 2 c ), an air flow gap 3 1 g ( 3 2g ) through which the cooling air of the cooling fan 4 1 flows is formed, whereby the liquid flow path 3 can flow through Cooling between 1 f ( 3 2f ) is cooled. Then, the refrigerant returning to the outlet side common longitudinal passage 3 1 e (32e) is discharged from the outlet portion 31b (32b) to reach the liquid flow path of the next heat receiving plate or the pump 20. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a system connection diagram of an embodiment of a liquid cooling system of the present invention. Fig. 2 is a system connection diagram showing another embodiment of the liquid cooling system of the present invention. Fig. 3 is a system connection diagram of another embodiment of the liquid cooling system of the present invention. Fig. 4 is a system connection diagram showing another embodiment of the liquid cooling system of the present invention. Fig. 5 is a plan view showing an arrangement example of a multi-blade fan and a heat sink. Figure 6 is a plan view of the piezoelectric pump unit. Fig. 7 is a cross-sectional view taken along line VII_VII of Fig. 6. Figure 8 is a perspective view of a series of heat sink units. Figure 9 is a front view of Figure 8. Figure 10 is a cross-sectional view of the χ-χ line of Figure 9. -11 - 200850137 [Explanation of main component symbols] 1 1,1 2,1 5 : Heat source 13, 14, 16, 17: Heated plates 13a, 14a, 16a, 17a, 17b, 17c: Liquid flow path 2 0: Pressure Electric pump (pump) 2 1 : Lower case 22: Upper case 24: Piezoelectric vibration element (diaphragm) -12-