200952615 九、發明說明： '【發明所屬之技術領域】 * 本發明涉及一種電路板，尤其涉及一種具備散熱設計 之電路板。 【先前技術】 由於電子產品體積日益縮小及晶片頻率之不斷提升， 使得PCB(Printed Circuit Board，印刷電路板）之組裝密度 不斷增加，所產生之發熱問題亦日益嚴重。PCB之優良散 ❹熱設計可有效提升散熱效能，降低成本並延長元件壽命。 為了加強PCB之散熱效能，目前大多採用於PCB上增加 散熱孔、鍍金屬薄膜、於PCB背面加裝金屬片、直接塗覆 散熱膏等方式來進行散熱。 一種電路板，其包括絕緣基板層、設於基板層上之銅 箔層及覆蓋於銅箔層上之綠漆。其中，銅箔層表面未被綠 漆所覆蓋處形成裸露之橫向與縱向交錯設置之金屬表面。 當該電路板過錫爐時，焊錫能夠附著於上述裸露表面而形 ©成十字或井字形實心焊錫條，以達散熱之功效。 然而，由於上述十字或井字形焊錫條之設計會佔用較 大面積，而實際電路板上之元件數量大，密集度高，位置 關係複雜，有可能找不到一片完全空白之銅箔區域用於佈 設上述焊錫條，故該散熱設計有較大局限性，較難應用於 一些元件較多較密之電路板。 【發明内容】 鑒於上述狀況，有必要提供一種散熱設計較為靈活， 200952615 適用範圍較廣之電路板。 一種電路板，包括基板層和設於基板層表面上之散熱 層。散熱層表面上設有複數個彼此分離之散熱塊。 由於該電路板使用了複數個彼此分離之散熱塊來達到 散熱之效果，可根據電路板上各元件的佈局合理確定散熱 塊的位置，因而能約適應電路板上元件較多，分佈較複雜 等情況之散熱需求。 【實施方式】 ❹ 下面將結合附圖及實施例對本發明之電路板作進一步 詳細說明。 請參見圖1及圖2，本發明實施例一之電路板10包 括：以絕緣材料所製成之基板層11、設於該基板層11表 面上之散熱層12、覆蓋於該散熱層12表面上之一層絕緣 綠漆13、複數個彼此分離之散熱塊14及複數個用於焊接 電子元件之焊盤15。其中，散熱層12可為銅箔、鋁箔或 其他導熱金屬所構成，優選為銅箔，散熱塊14為焊錫所構 ❹成。 散熱塊14之製造方法是先於該散熱層12表面覆蓋上 一整層綠漆13，然後除去部分綠漆13以使其底部之散熱 層12部分表面裸露在外而形成裸銅121。當電路板10過 錫爐時，液態之錫料能夠附著於裸銅121上冷卻後形成實 心且有隆起表面之散熱塊14。裸銅121之形狀可為複數個 彼此分離之圓、橢圓或多邊形，例如三角形、正方形等。 於本實施例中，為使焊錫之内聚力最為均勻化，裸銅121 之形狀優選為複數個彼此分離之圓；為了節省設計時間， 200952615 更為優選之方案為複數個彼此分離且直徑相等之圓，散熱 k 14優選為形狀相同、體積相等之近半球體。 嘉電路板10上各焊盤15之間隔較遠，形成了 一定面 積之空白綠漆13時，裸銅121之排列分佈可為如圖1所示 之整齊間隔排列。組成裸銅121之圓之直徑D能夠直接影 響散熱塊14之散熱效果。直徑D過小，造成散熱塊14之 表面積過小，影響散熱；直徑D過大，有限面積内圓之個 數必將下降，因此造成散熱塊14之總表面積下降，影響散 ❹熱’故’綜合考慮實際之散熱狀況，圓之直徑D於1.2毫 米至2.0毫米之間。本實施例中，直徑d等於1.6毫米。 而且’為了防止散熱塊14排列過密而影響對流散熱效果， 相鄰圓邊緣至邊緣之最近之距離L1以大於等於〇·5毫米較 佳。 圖3為本發明之實施例二所提供之電路板。由圖3可 知’當電路板10上元件較多，焊盤15排布較密，無法找 到一大片空白綠漆13時，散熱塊14還可分佈於複數個焊 ❹盤15之間隙處’如此便可在不改變電路板原設計佈局之狀 況下充分利用空間散熱。為了防止過錫爐時焊料從裸銅 121中溢出與零件腳短接，組成裸銅121之圓之邊緣與焊 盤15之邊緣之間之最近距離L2以大於等於0.3毫米較佳。 電路板10於使用過程中，發熱元件所產生之熱量能夠 通過散熱層12迅速地轉移到各形狀規則之散熱塊14之隆 起表面而散逸至空氣中。由於複數個彼此分離之散熱塊14 可以較為靈活地穿插設於電路板1〇各焊盤15之間，而不 會對電路板10上原設計佈局產生干擾，因此本發明之散熱 200952615 設計適用於一些元件數量較多，密集度較高之電路板。 綜上所述，本發明符合發明專利要件，爰依法提出專 •利申請。惟，以上所述者僅為本發明之較佳實施方式，本 發明之範圍並不以上述實施方式為限，舉凡熟悉本案技藝 之人士，於爰依本案發明精神所作之等效修飾或變化，皆 應包含於以下之申請專利範圍内。 【圖式簡單說明】 圖1係本發明實施例一之電路板之平面示意圖。 圖2係圖1所示電路板沿ll-π之剖面圖。 圖3係本發明實施例二之電路板之平面示意圖。 【主要元件符號說明】 (本發明） 電路板 10 基板層 11 散熱層 12 裸銅 121 綠漆 13 散熱塊 14 焊盤 15 裸銅之直徑 D 裸鋼相鄰圓邊緣 L1 裸銅邊緣至焊盤 L2 之間之最近距離 邊緣之最近距離200952615 IX. Description of the invention: '[Technical field to which the invention pertains] * The present invention relates to a circuit board, and more particularly to a circuit board having a heat dissipation design. [Prior Art] Due to the shrinking size of electronic products and the increasing frequency of wafers, the assembly density of printed circuit boards (PCBs) is increasing, and the heat generation problem is becoming more and more serious. The excellent thermal design of the PCB improves heat dissipation, reduces cost and extends component life. In order to enhance the heat dissipation performance of the PCB, most of the current methods are to add heat dissipation holes, metallized films, metal sheets on the back side of the PCB, and directly apply thermal grease to dissipate heat. A circuit board comprising an insulating substrate layer, a copper foil layer disposed on the substrate layer, and a green lacquer overlying the copper foil layer. Wherein, the surface of the copper foil layer is not covered by the green paint to form a bare metal surface which is laterally and longitudinally staggered. When the board passes through the tin furnace, the solder can adhere to the exposed surface to form a solid cross-shaped or cross-shaped solder strip to achieve heat dissipation. However, since the design of the above-mentioned cross or well-shaped solder bar will occupy a large area, and the number of components on the actual circuit board is large, the density is high, and the positional relationship is complicated, it may be impossible to find a completely blank copper foil area for The above-mentioned solder strips are arranged, so the heat dissipation design has a large limitation, and it is difficult to apply to some circuit boards with more dense components. SUMMARY OF THE INVENTION In view of the above situation, it is necessary to provide a circuit board with a relatively wide heat dissipation design and a wide application range of 200952615. A circuit board comprising a substrate layer and a heat dissipation layer disposed on a surface of the substrate layer. A plurality of heat dissipating blocks separated from each other are disposed on the surface of the heat dissipating layer. Since the circuit board uses a plurality of heat dissipating blocks separated from each other to achieve the effect of dissipating heat, the position of the heat dissipating block can be reasonably determined according to the layout of each component on the circuit board, thereby being able to adapt to more components on the circuit board, and the distribution is more complicated. The need for heat dissipation. [Embodiment] The circuit board of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Referring to FIG. 1 and FIG. 2, the circuit board 10 of the first embodiment of the present invention includes a substrate layer 11 made of an insulating material, a heat dissipation layer 12 disposed on the surface of the substrate layer 11, and a surface of the heat dissipation layer 12. The upper layer of insulating green paint 13, a plurality of heat dissipating blocks 14 separated from each other, and a plurality of pads 15 for soldering electronic components. The heat dissipation layer 12 may be made of copper foil, aluminum foil or other heat conductive metal, preferably a copper foil, and the heat dissipation block 14 is made of solder. The heat dissipating block 14 is manufactured by coating a surface of the heat dissipating layer 12 with a whole layer of green lacquer 13 and then removing part of the green lacquer 13 so that a part of the surface of the heat dissipating layer 12 at the bottom is exposed to form bare copper 121. When the circuit board 10 passes through the tin furnace, the liquid tin material can adhere to the bare copper 121 to form a solid heat sink 14 having a raised surface after cooling. The shape of the bare copper 121 may be a plurality of circles, ellipses or polygons separated from each other, such as a triangle, a square, or the like. In this embodiment, in order to make the cohesion of the solder most uniform, the shape of the bare copper 121 is preferably a plurality of circles separated from each other; in order to save design time, a more preferable solution is 200952615, which is a plurality of circles separated from each other and having the same diameter. The heat dissipation k 14 is preferably a near hemisphere having the same shape and the same volume. When the pads 15 on the circuit board 10 are spaced far apart to form a blank green paint 13 of a certain area, the arrangement of the bare coppers 121 may be arranged at regular intervals as shown in FIG. The diameter D of the circle constituting the bare copper 121 can directly affect the heat dissipation effect of the heat sink block 14. If the diameter D is too small, the surface area of the heat dissipating block 14 is too small, which affects heat dissipation; if the diameter D is too large, the number of inner circles of the limited area is bound to decrease, thereby causing the total surface area of the heat dissipating block 14 to decrease, which affects the heat of the heat sink. The heat dissipation condition, the diameter D of the circle is between 1.2 mm and 2.0 mm. In this embodiment, the diameter d is equal to 1.6 mm. Further, in order to prevent the heat dissipation block 14 from being arranged too densely to affect the convection heat dissipation effect, the closest distance L1 from the adjacent round edge to the edge is preferably 〇·5 mm or more. 3 is a circuit board provided in Embodiment 2 of the present invention. As can be seen from FIG. 3, when there are many components on the circuit board 10 and the pads 15 are arranged densely, and a large blank green paint 13 cannot be found, the heat dissipation block 14 can also be distributed in the gap between the plurality of solder pads 15 Make full use of space cooling without changing the original layout of the board. In order to prevent the solder from overflowing from the bare copper 121 and short-circuiting the component legs during the over-tin furnace, the closest distance L2 between the edge of the circle constituting the bare copper 121 and the edge of the pad 15 is preferably 0.3 mm or more. During use of the circuit board 10, heat generated by the heat generating component can be rapidly transferred to the raised surface of each of the regularly shaped heat radiating blocks 14 through the heat dissipation layer 12 to escape into the air. Since a plurality of heat dissipating blocks 14 separated from each other can be flexibly inserted between the pads 15 of the circuit board 1 without interfering with the original design layout on the circuit board 10, the heat dissipation 200952615 of the present invention is suitable for some applications. A board with a large number of components and a high density. In summary, the present invention complies with the requirements of the invention patent, and applies for a special application in accordance with the law. However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be equivalently modified or changed in accordance with the spirit of the invention. All should be included in the scope of the following patent application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of a circuit board according to a first embodiment of the present invention. Figure 2 is a cross-sectional view of the circuit board of Figure 1 taken along line ll-π. 3 is a schematic plan view of a circuit board according to Embodiment 2 of the present invention. [Main component symbol description] (Invention) Circuit board 10 Substrate layer 11 Heat dissipation layer 12 Bare copper 121 Green paint 13 Heat sink block 14 Pad 15 Bare copper diameter D Bare steel adjacent round edge L1 Bare copper edge to pad L2 The closest distance between the nearest distance edges