Heat dissipation structure of PCB substrate

Abstract

The utility model discloses a heat radiation structure of a PCB substrate, comprising a board body, the surface of the board body is provided with a copper foil layer, the board body is provided with a plurality of groove-strip-shaped pads, the length-width ratio of the groove-strip-shaped pads is greater than 1, the groove-strip-shaped pads penetrate from the front surface of the board body to the back surface of the board body, and the copper foil layer is arranged on the surface of the board body. A part or all of the groove-strip-shaped bonding pads are filled with heat conduction heat dissipation structures, and the inner walls of the remaining groove-strip-shaped bonding pads are covered with heat conduction layers with the middles hollowed out. According to the utility model, the independent heat conduction and heat dissipation effect is realized by utilizing the groove-strip-shaped bonding pad, or the heat dissipation performance is enhanced and the product quality is improved through the combination of two heat dissipation modes of heat conduction and heat dissipation and air convection.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB substrates, in particular to a heat dissipation structure of a PCB substrate. Background Art

[0002] At present, the electronics industry, with the rapid development of electronic technology, especially consumer electronics, are increasingly tending to be smaller and more portable, such as mobile phones, digital cameras, etc., which makes the heat generated per unit volume of electronic components rise step by step. In the current fashion trend that the appearance structure of products will become slimmer, the PCB board will also become smaller with the structure. How to make the PCB board more precise becomes particularly important and will become a key technology that needs to be solved. Better heat dissipation can improve the compactness and reliability of product structure.

[0003] On the one hand, the existing heat sinks have complex preparation processes, high energy consumption and high costs; on the other hand, due to their processing requirements and material properties, it is not easy to make a structure with heat dissipation characteristics. If additional heat dissipation equipment is added to solve the problem of excessively high local temperature of the PCB board, the cost of the product will be greatly increased. The copper foil on the PCB board is used to dissipate heat. The surface solder mask oil needs to be removed for copper foil heat dissipation, so that the copper foil is exposed to the air to achieve heat exchange. There are also some solutions in the prior art that drill circular through holes on the PCB board and use the circular through holes to enhance the effect of air convection. The inside of the circular through hole is not processed, and the heat is only taken away by the convection effect generated by the air flowing through the circular through hole. In addition, as the manufacturing process proceeds, some circular through holes will be blocked due to their small size, affecting the heat dissipation effect.

[0004] In order to achieve heat dissipation of the circuit board, there are different processing methods in the prior art, such as:

[0005] CN211606920U discloses a circuit board that is easy to dissipate heat. A groove is provided on the top of the circuit board body, and a heat dissipation strip is movably embedded in the groove. A silver foil layer is attached to the top of the copper core board layer, and a graphite heat sink layer is attached to the surface of the silver foil layer. Mounting holes are provided at the four corners of the top of the circuit board body, and heat dissipation holes are provided on the heat dissipation strip. The copper core board layer, the silver foil layer, the graphite heat sink layer, the mounting groove, the heat dissipation strip, the mounting hole, the heat dissipation hole and the heat dissipation silicone grease are used in combination to achieve heat dissipation. Utility Model Content

[0006] In order to solve the above technical problems, the utility model provides a heat dissipation structure of a PCB substrate, which can improve the heat dissipation performance without increasing the size of the board.

[0007] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0008] A heat dissipation structure of a PCB substrate comprises a board body, a copper foil layer is provided on the surface of the board body, a plurality of slot-shaped pads are provided on the board body, the aspect ratio of the slot-shaped pads is greater than 1, the slot-shaped pads extend from the front side of the board body to the back side of the board body, the interior of some or all of the slot-shaped pads is filled with a heat conduction heat dissipation structure, and the inner walls of the remaining slot-shaped pads are covered with a heat conductive layer and are hollow in the middle.

[0009] As a further improvement, the heat conduction and heat dissipation structure is a tin bar.

[0010] As a further improvement, the end surface of the heat conduction and heat dissipation structure is flush with the surface of the plate body.

[0011] As a further improvement, the tin bar is formed by filling the slot-shaped solder pad with tin liquid after the plate passes through a wave soldering furnace.

[0012] As a further improvement, when the interior of a portion of the slot-shaped pads is filled with the heat conduction and heat dissipation structure, the slot-shaped pads are spaced apart from the remaining slot-shaped pads whose inner walls are covered with the heat conduction layer.

[0013] As a further improvement, the width of the slot-shaped pad is 1-2 mm.

[0014] As a further improvement, when the interior of a portion of the slot-shaped solder pads is filled with the heat conduction and heat dissipation structure, the slot-shaped solder pads and the remaining slot-shaped solder pads whose inner walls are covered with the heat conduction layer are respectively located on both sides of the board.

[0015] As a further improvement, the heat conducting layer is a tin layer.

[0016] As a further improvement, the tin layer is formed by spraying tin on the inner wall of the slot-shaped pad.

[0017] As a further improvement, the length of the slot-shaped pad is 9-12 mm.

[0018] Compared with the prior art, the utility model has the following beneficial technical effects:

[0019] By setting a slot-shaped pad so that its aspect ratio is greater than 1, the slot-shaped pad is filled with tin liquid to form a tin bar, and the tin bar is used to make the slot-shaped pad a packaging structure. The end face of the tin bar is kept flush with the surface of the board without protruding, which will not affect the assembly of other electronic components and maintain the flatness of the board surface; the tin bar has high thermal conductivity and is in direct contact with the air to conduct the heat in the board and achieve rapid heat exchange with the air. By setting a plurality of slot-shaped pads filled with tin bars, the tin bars are connected with copper foil, and the heat dissipation performance is improved by relying on the copper foil on the surface of the PCB board.

[0020] A portion of slot-shaped solder pads with a hollow interior is also provided. In this portion of the slot-shaped solder pads, a heat-conducting layer is formed only on the inner wall solder. When air passes through this portion of the slot-shaped solder pads, it comes into contact with the heat-conducting layer, which is equivalent to increasing the area in contact with the air, that is, increasing the heat dissipation area, thereby increasing the heat dissipation performance. Moreover, compared with traditional circular heat dissipation holes, the slot-shaped solder pads have a larger internal area and are less likely to cause blockage problems, thereby increasing the air circulation path and achieving a better heat dissipation effect.

[0021] By combining the two heat dissipation structures, the diversity of heat dissipation is formed, the heat dissipation performance of the PCB board is enhanced, and the heat on the PCB board can be dissipated to the outside in time, so that the heat of the PCB board will not be too high, which plays a protective role for various electronic components and avoids working in a high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the planar structure of a PCB board that has not been soldered in the present invention;

[0023] Figure 2 This is a schematic diagram of the planar structure of the first embodiment of the utility model;

[0024] Figure 3 This is a schematic cross-sectional structure diagram of the first embodiment of the present utility model;

[0025] Figure 4 This is a schematic diagram of the planar structure of the second embodiment of the present utility model;

[0026] Figure 5 It is a schematic cross-sectional structure diagram of the second embodiment of the present utility model.

[0027] Reference numerals:

[0028] Board body 1, copper foil layer 2, slot-shaped solder pad 3, tin bar 4, heat dissipation tin wall 5, heat dissipation hole 6. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] In the description of the present utility model, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like are involved, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0031] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] Embodiment 1

[0033] like Figure 1-3 As shown, a heat dissipation structure of a PCB substrate includes a board body 1, and the board body 1 is a multi-layer board, such as a two-layer, four-layer board or a board with other layers. A copper foil layer 2 is provided on the surface of the board body 1, and a plurality of slot-shaped pads 3 are provided on the board body 1, and the aspect ratio of the slot-shaped pads 3 is greater than 1. The slot-shaped pads 3 penetrate from the front of the board body 1 to the back of the board body, and the copper foil layer 2 of the board body is exposed at the port of the slot-shaped pads 3. The plurality of slot-shaped pads 3 are distributed in a display structure, or distributed on the board body in other preset rules. The slot-shaped pads are arranged in an area that does not affect the assembly space of electronic components, especially around electronic components that generate a large amount of heat during operation, so as to dissipate the heat generated by the operation of the electronic components in a timely manner. The length of the slot-shaped pads is set to 10 mm, and the depth is the thickness of the board body, such as the thickness of the board body is 1 mm.

[0034] The interior of the slot-shaped pad 3 is filled with the heat conduction heat dissipation structure, so that the slot-shaped pad 3 is transformed from a hollow structure to a solid structure. Since the board body is a multi-layer board, the slot-shaped pad 3 runs through all layers of the board body. The heat conduction heat dissipation structure absorbs heat from other areas and then transfers it to the surface of the heat conduction heat dissipation structure to dissipate the heat into the air to achieve the purpose of heat dissipation.

[0035] In this embodiment, the interiors of all the slot-shaped pads on the board are filled with heat conduction and heat dissipation structures.

[0036] The end surface of the heat conduction and heat dissipation structure is flush with the surface of the board body, so that the heat conduction and heat dissipation structure does not protrude to affect the assembly of other electronic components, and the structure is also more compact.

[0037] The heat conduction and heat dissipation structure is a tin bar 4, which is formed by filling the slot-shaped pad with tin liquid after the board body 1 passes through the wave crest tin furnace, so that the slot-shaped pad 3 is transformed from a leaky structure to a solid structure. The end face of the tin bar 4 contacts the copper foil layer 2 on the surface of the board body 1, and the copper foil layer 2 contacts the heat and then quickly dissipates the heat into the air. The two sides of the tin bar 4 are respectively located on the front and back of the board body, directly exposed to the air. The heat absorbed by the tin bar is heat exchanged by contacting with the air to achieve the heat dissipation function.

[0038] In this embodiment, unlike the traditional method of using heat dissipation holes to achieve heat dissipation, air is not used to flow through the inside of the board to take away the heat. Since the tin bar is a material with high thermal conductivity, the heat from other areas on the board is transferred toward the tin bar. After the heat enters the inside of the tin bar, it is transferred to the surface of the tin bar. The surface of the tin bar is in direct contact with the external air, and the temperature drops faster than that inside the tin bar. Continuous heat conduction and heat dissipation achieve the purpose of dissipating the heat on the board to the outside and cooling it.

[0039] As for the setting of the tin bar, it is formed by filling the tin liquid and cooling it. The production process is relatively simple and will not cause difficulties in the implementation of the plan.

[0040] By setting a plurality of slot-shaped pads 3, when the size of the PCB board is changed, the original free space of the PCB board is utilized to achieve heat conduction through the tin bar, and the heat is further dissipated, so as to avoid excessive temperature on the PCB board, thereby protecting the electronic components. In particular, it is suitable for devices with limited space and high-power heating devices, and the light and thin design of the device is not affected while the heat dissipation performance is improved.

[0041] Embodiment 2

[0042] refer to Figure 1-5As shown, a heat dissipation structure of a PCB substrate includes a board body 1, which is a multi-layer board, such as a two-layer board, a four-layer board or a board with other layers. A copper foil layer 2 is provided on the surface of the board body 1, and a plurality of slot-shaped pads 3 are provided on the board body 1. The length-to-width ratio of the slot-shaped pads 3 is greater than 1. The slot-shaped pads 3 penetrate from the front side of the board body 1 to the back side of the board body, and the copper foil layer 2 of the board body 1 is exposed at the end of the slot-shaped pads 3.

[0043] The interior of a part of the slot-shaped pad 3 is filled with a heat conduction heat dissipation structure, and the heat conduction heat dissipation structure is a tin bar 4, which is formed by filling the slot-shaped pad with tin liquid after the board body 1 passes through a wave crest tin furnace, so that the slot-shaped pad 3 is transformed from a leaky structure to a solid structure. The end face of the tin bar 4 contacts the copper foil layer 2 on the surface of the board body 1, and the copper foil layer 2 contacts the heat and then quickly dissipates the heat into the air. The two sides of the tin bar 4 are respectively located on the front and back of the board body, and are directly exposed to the air. The heat absorbed by the tin bar is heat exchanged by contacting with the air to achieve the heat dissipation function.

[0044] At the same time, the inner wall of the remaining slot-shaped pad 3 is covered with a layer of heat-conducting layer 5 and the middle is empty. The heat-conducting layer 5 fills the entire inner wall of the slot-shaped pad 3 to form a through-hole structure for air circulation. The middle empty structure is long strip rather than circular, which is not easy to cause blockage during processing or use. The thermal conductivity of the heat-conducting layer is higher than that of the board, so the heat in other areas of the board will be conducted toward the heat-conducting layer and absorbed by the heat-conducting layer. The whole is formed into an air convection heat dissipation structure.

[0045] When air flows through the middle leakage area 6 of this part of the slot-shaped pad 3, the air will come into contact with the thermal conductive layer, and the heat on the thermal conductive layer 5 will be carried away by the air. The air will come into contact with the entire circumference of the middle leakage of the slot-shaped pad, which is equivalent to increasing the contact area of ​​the entire side wall and improving the heat dissipation.

[0046] The heat conducting layer is a tin layer, and the tin layer is formed by spraying tin on the inner wall of the slot-shaped pad. The tin material has a higher heat conducting layer, which is higher than the thermal conductivity of the board body, and the heat on the board body will be conducted toward the tin layer.

[0047] In this embodiment, two different types of heat dissipation structures are provided, namely, a heat conduction heat dissipation structure and an air convection structure, which are combined to enhance the heat dissipation performance.

[0048] The distribution rules of the heat conduction heat dissipation structure and the air convection heat dissipation structure can be flexibly set according to the arrangement of the electronic components on the board, such as including interval distribution and being located on both sides of the board. When the interval distribution is used, the heat conduction heat dissipation structure and the air convection heat dissipation structure can be distributed in separate columns, such as two adjacent columns, one of which is entirely heat conduction heat dissipation structure and the other is entirely air convection heat dissipation structure; or in the same column, both heat conduction heat dissipation structure and air convection heat dissipation structure are included. In addition, the heat conduction heat dissipation structure can be selected in the area covered by electronic components to meet the needs of electronic component installation, and the air convection heat dissipation structure can be selected in the blank area not covered by electronic components to increase air flow.

[0049] The heat conduction heat dissipation structure uses the conductivity of the tin bar to achieve heat dissipation; the air convection heat dissipation structure uses the contact between the air flowing through the slot-shaped solder pad and the surrounding tin layer to take away the heat to achieve heat dissipation, that is, to increase the air contact area.

[0050] Taking a multilayer board with a thickness of 1.6 mm as an example, the width of the slot pad is 1 mm, and the length of the slot pad is defined as 10 mm. Assuming the thickness of the heat conductive layer is 0.2 mm, after the inner wall of the slot pad 3 is provided with a tin layer, the length of the remaining middle leak area is 9.6 mm and the width is 0.6 mm. For the convenience of calculation, a rectangle is used as an example for explanation.

[0051] The sum of the areas of the two sides in the length direction is 9.6*1.6*2 square millimeters, and the sum of the areas of the two sides in the width direction is 0.6*1.6*2 square millimeters. That is to say, when air passes through the slot-shaped pad, it will contact the surrounding tin layers respectively, increasing the air contact area. In addition, the long strip-shaped vias will not be easily blocked to form airflow windows, which increases the airflow path inside the device and enhances the heat dissipation performance.

[0052] Compared with traditional circular heat dissipation holes, the probability of being blocked is greatly reduced. At the same time, the internal tin spraying treatment forms a tin layer for heat dissipation, which is conducive to heat conduction. Under the same PCB copper foil size, the heat dissipation area is increased; the air convection environment is increased to improve the heat dissipation effect.

[0053] Comparative Example

[0054] like Figure 1 As shown, a heat dissipation structure of a PCB substrate includes a board body 1, which is a multilayer board. A copper foil layer 2 is provided on the surface of the board body 1. A plurality of slot-shaped pads 3 are provided on the board body 1. The aspect ratio of the slot-shaped pads 3 is greater than 1. The slot-shaped pads 3 extend from the front side of the board body 1 to the back side of the board body. The copper foil layer 2 of the board body is exposed at the end of the slot-shaped pads 3.

[0055] In this comparative example, no treatment is performed inside the slot-shaped pad, that is, no tin strip or tin layer as described in Example 1 and Example 2 is set, and heat is only dissipated by air flowing through the slot-shaped pad. Under this structure, the contact area of ​​air is also increased. However, since there is no heat-conducting layer inside the slot-shaped pad, the heat from other areas on the board will not be relatively concentratedly conducted to the slot-shaped pad, and the heat dissipation is relatively limited compared to the solutions of Example 1 and Example 2, and more heat cannot be taken away.

[0056] It should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat dissipation structure of a PCB substrate, comprising a board body, a copper foil layer being provided on the surface of the board body, characterized in that: The board body is provided with a plurality of slot-shaped pads, the aspect ratio of which is greater than 1, and the slot-shaped pads extend from the front side of the board body to the back side of the board body. The interior of some or all of the slot-shaped pads is filled with a heat conduction and heat dissipation structure, and the inner walls of the remaining slot-shaped pads are covered with a heat conductive layer and are hollow in the middle.

2. The heat dissipation structure of the PCB substrate according to claim 1, characterized in that: The heat conduction and heat dissipation structure is a tin bar.

3. The heat dissipation structure of the PCB substrate according to claim 1, characterized in that: The end surface of the heat conduction and heat dissipation structure is flush with the surface of the plate body.

4. The heat dissipation structure of the PCB substrate according to claim 2, characterized in that: The tin bar is formed by filling the slot-shaped solder pad with tin liquid after the plate body passes through a wave soldering furnace.

5. The heat dissipation structure of the PCB substrate according to claim 1, characterized in that: When the interior of a portion of the slot-shaped pads is filled with the heat conduction and heat dissipation structure, the slot-shaped pads are spaced apart from the remaining slot-shaped pads whose inner walls are covered with the heat conduction layer.

6. The heat dissipation structure of the PCB substrate according to claim 1 or 2, characterized in that: The width of the slot-shaped pad is 1-2 mm.

7. The heat dissipation structure of the PCB substrate according to claim 1, characterized in that: When the interior of a portion of the slot-shaped pads is filled with the heat conduction and heat dissipation structure, the slot-shaped pads and the remaining slot-shaped pads whose inner walls are covered with the heat conduction layer are respectively located on two sides of the board body.

8. The heat dissipation structure of the PCB substrate according to claim 1, characterized in that: The heat conducting layer is a tin layer.

9. The heat dissipation structure of the PCB substrate according to claim 8, characterized in that: The tin layer is formed by spraying tin on the inner wall of the slot-shaped pad.

10. The heat dissipation structure of the PCB substrate according to claim 6, characterized in that: The length of the slot-shaped pad is 9-12 mm.

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