Inflation-type phase change device and electronic equipment

Abstract

The present invention relates to the field of electronic heat dissipation, and discloses an inflatable phase change device, a heat dissipation system and an electronic device. The inflatable phase change device comprises a substrate, the interior of the substrate is inflated to form a flat cavity; a concave support column is provided between the upper and lower walls of the cavity of the substrate, and the upper and lower outer surfaces of the support column form an island; the cavity around the island of the substrate forms a flow channel, and the flow channel is filled with a refrigerant for heat dissipation after vacuum treatment; the flow channel and the island form an uneven surface thermal functional structure, and the substrate is provided with threaded holes for fixing around; the inflated height of the substrate does not exceed 1mm; the size of the flow channel does not exceed 6mm; the size of the island does not exceed 6mm. The concave island of the inflatable phase change device provided by the present invention can re-induce the boundary layer and disturb the boundary layer, improve the convective heat transfer coefficient, and is conducive to the heat dissipation of the chip. Compared with the prior art, the thermal conductivity efficiency is higher and the appearance size of the electronic device is thinner.

Description

Technical Field

[0001] The invention relates to the field of electronic heat dissipation, and in particular to an inflation-type phase change device, a heat dissipation system and electronic equipment. Background Art

[0002] As the integration of chips continues to increase, the requirements for processing power, communication network capabilities, etc. increase, and power consumption also increases accordingly, resulting in a continuous increase in heat generation power. According to the temperature rise characteristics of the chip, the probability of its failure will increase exponentially with the increase in temperature. In order to solve the speed reduction problem caused by heat dissipation limitations, two approaches are generally adopted: increasing the number of shell openings and increasing the thickness of the body. However, these two approaches bring sacrifices in appearance design, making the appearance of router products relatively heavy and not delicate and beautiful; in addition, the openings on the upper surface of the product will make it easy for dust to enter its interior, and the accumulated dust and dirt may affect the service life of the product. It can be seen that the focus of research is to reduce the temperature of the chip in the small space of the router with a radiator with high heat dissipation efficiency.

[0003] Traditional electronic products, such as routers, usually rely on aluminum plates for heat dissipation. The thermal conductivity of aluminum plates is only about 222W / (m·K), while the thermal conductivity of inflatable phase change devices is about 5000W / (m·K). The thermal conductivity of inflatable phase change devices is about 22 times that of aluminum plates, which has a better heat-dissipating effect; the small grooves of inflatable phase change devices can re-induce the boundary layer and disrupt the boundary layer, thereby improving the convective heat transfer coefficient and facilitating the heat dissipation of the chip; the reasonable opening design on the inflatable phase change device allows a better air flow channel to be formed inside the router, allowing external cold air to enter the router, and the cold air can conduct convective heat exchange with the internal devices, and the internal heat is exported to the outside air to achieve the heat dissipation effect. In view of the above advantages, the chip temperature is transferred to the heat dissipation device through heat conduction, and the reasonable design of the air flow channel allows the heat of the heat dissipation device to be transferred to the outside through convective heat exchange, thereby effectively reducing the temperature of the router chip.

[0004] In order to solve the speed reduction problem caused by heat dissipation limitations, mainstream router products on the market currently generally adopt two methods: increasing the body thickness. Both methods result in sacrifices in appearance design, making the appearance of router products relatively thick and not delicate and beautiful enough. Summary of the invention

[0005] In order to overcome one or more of the above technical problems, the purpose of the present invention is to provide an inflatable phase change device, a heat dissipation system and an electronic device. From the perspective of the overall design of electronic products, a heat spreader of a gas-liquid phase change device is used to greatly and effectively improve the heat dissipation efficiency of electronic products while maintaining a light, thin and small router structure.

[0006] The present invention provides the following technical solutions:

[0007] First aspect

[0008] The present invention provides an inflation-type phase change device, which comprises a substrate, wherein the interior of the substrate is inflated to form a flat cavity; a plurality of inwardly concave support columns are arranged between the upper and lower walls of the cavity of the substrate, and the upper and lower outer surfaces of the support columns form an isolated island, and the cavity around the isolated island forms a flow channel, and the flow channel is filled with a refrigerant for heat dissipation after vacuum treatment; the flow channel and the isolated island form an uneven surface thermal functional structure, and the substrate is provided with threaded holes for fixing around it; the inflation height of the substrate does not exceed 1 mm; the size of the flow channel does not exceed 6 mm; the isolated island The size of the island does not exceed 6mm; a thermally conductive gasket for heat conduction is provided between the inflatable phase change device and the PCB board that needs heat dissipation; a screen is provided below the inflatable phase change device located at the upper part of the PCB board, and an island through hole is provided in the island of the inflatable deformation device located at the upper part of the PCB board, at a position where the projections of the screen and the island on the plane of the substrate do not overlap; an island through hole is provided in the island of the inflatable phase change device located at the lower part of the PCB board, at a position that does not contact the thermally conductive gasket.

[0009] In the above-mentioned embodiment, the uneven surface thermal functional structure formed by the flow channel and the island can increase the natural convection heat exchange between the radiator and the air; the interior of the inflatable phase change device is in a vacuum state, and the refrigerant as the working medium vaporizes at the heat source position to absorb heat, and liquefies and releases heat in the area outside the heat source, realizing the process of gas-liquid phase change. The thermal conductivity of the inflatable phase change device is dozens of times higher than that of the aluminum plate, which effectively improves the temperature uniformity and heat conduction effect and avoids the hot spot concentration phenomenon; the inflatable phase change device has a surface thermal functional structure on the inflated side. This structure theoretically has the ability to induce turbulence, can disturb the flow boundary layer, and re-trigger the boundary layer. Since the starting position of the boundary layer of the fluid has a higher convection heat transfer coefficient, the convection heat transfer coefficient at the starting position of the wall fluid is the highest, and the surface thermal functional structure increases the specific surface area and has the effect of enhancing the heat dissipation effect, so it is beneficial to reduce the chip temperature. There is liquid refrigerant, i.e., working fluid, between the island and the flow channel. The island and the flow channel are relatively small, and the inflation-type phase change device is also conducive to gas-liquid phase change under reverse gravity to achieve the effect of uniform heat.

[0010] In the island of the inflatable phase change device located at the upper part of the PCB board, a number of island through holes are opened at positions where the projections of the screen cover and the island on the plane where the substrate is located do not overlap; the center of the island of the inflatable phase change device located at the lower part of the PCB is opened at a position that does not contact the thermal conductive pad. Such a structure allows air to flow directly into the PCB board from the through hole of the lower inflatable phase change device to increase the heat transfer coefficient; the temperature of the chip rises and the gas expands due to heat, and the gas can flow out directly from the upper inflatable phase change device; based on the above situation, an air flow channel for optimizing heat dissipation is formed inside the inflatable phase change device, thereby improving the convective heat transfer effect.

[0011] According to some embodiments, a plurality of protrusions are provided on the edges around the substrate to form reinforcing ribs.

[0012] In the above embodiment, the reinforcing ribs are used to prevent the blown phase change device from contacting with the electronic device and damaging the electronic device.

[0013] According to some embodiments, the threaded holes of the substrate are formed by a flanging process.

[0014] In the above implementation, the threaded hole adopts a flanging process, which is conducive to firmly fixing the PCB board and the blown phase change device with screws.

[0015] According to some embodiments, a positioning piece for snap-fitting and positioning is provided on the side edge of the substrate.

[0016] According to some embodiments, the sum of the thickness of the upper wall and the lower wall of the substrate does not exceed 1.5 mm.

[0017] According to some embodiments, the array of support columns in each row constitutes a group, the arrays of two adjacent groups of support columns are arranged in a staggered manner, and the staggered angle between adjacent islands is 60°.

[0018] In the above embodiment, the flow resistance coefficient of the support column is larger at an angle of 60° compared to an angle of 90°, which is more conducive to enhancing heat exchange.

[0019] Second aspect

[0020] The present invention also provides a heat dissipation system including any of the above-mentioned inflation-type phase change devices, and also includes the thermal conductive pad, which is arranged between the inflation-type phase change device and a PCB board that needs heat dissipation.

[0021] In the above embodiment, the thermally conductive gasket plays a role in heat conduction between the PCB board and the second heat spreader; the second thermally conductive gasket allows a certain distance between the PCB board and the second heat spreader, which not only plays a certain protective role for the electronic components under the PCB board, but also allows the direct contact between the PCB board and the second heat spreader to have a certain convection heat exchange effect, further achieving a good effect on the heat dissipation of the electronic chip.

[0022] The third aspect

[0023] The present invention also provides an electronic device including the above-mentioned heat dissipation system, which includes a first shell, a screen cover, the PCB board and a second shell arranged in sequence from top to bottom; the inflatable phase change device is arranged between the first shell and the PCB board and / or between the PCB board and the second shell.

[0024] According to some embodiments, the inflatable phase change device is a heat spreader, wherein the inflatable phase change device located above the PCB board is defined as a first heat spreader, and the inflatable phase change device located below the PCB board is defined as a second heat spreader; the first heat spreader is arranged below the first outer shell and is located on the screen cover, a first thermally conductive gasket for heat conduction is arranged below the screen cover, and the PCB board is below the first thermally conductive gasket; the second heat spreader is arranged above the second outer shell, and is covered with a second thermally conductive gasket, and the second thermally conductive gasket is located below the PCB board.

[0025] In the above implementation, the inflatable phase change device below the PCB board, i.e., the second heat spreader, if most of the electronic devices such as chips are located above the PCB board, the inflatable phase change device has a complex inflatable structure shape that is not easy to make, there are fewer electronic devices below the PCB board, and the lower part of the PCB board uses an inflatable phase change device for heat conduction, so the structure of the inflatable phase change device below is easier to manufacture. The inflatable phase change device above, i.e., the first heat spreader, has more cold air circulation flowing in from the lower surface of the lower second shell. In order to achieve a better convective heat transfer effect, the overall structure of the inflatable phase change device above is larger than that of the device below.

[0026] The second heat spreader and the PCB board are connected and heat transferred by a thermal pad. An island is set on the other side of the thermal pad that contacts the second heat spreader. The island is a solid structure with a high heat transfer coefficient, so it is more conducive to heat transfer. The second heat spreader is provided with an island and one side of the flow channel is placed downward, that is, placed against gravity. Due to the effect of gravity, more liquid is below the cavity, so the inflation height should not be too high, which makes it easier to achieve the effect of gas-liquid phase change. The inflation height of the inflation-type phase change device below is more suitable to be 1mm.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides an inflatable phase change device, a heat dissipation system and an electronic device. Compared with the prior art, the inflatable phase change device has a better temperature equalization effect, and the natural convection heat dissipation effect of the heat dissipation system is better. The electronic device provided by the present invention uses the inflatable phase change device for heat dissipation, because the thermal conductivity of the inflatable phase change device is multiple times that of the aluminum plate, and has a better heat equalization effect; the concave island of the inflatable phase change device can re-induce the boundary layer and disturb the boundary layer, the starting position of the boundary layer is the smallest, and the heat exchange capacity of the material and the air here is the highest. The concave island can re-trigger the boundary layer, improve the convection heat transfer coefficient, and is conducive to the heat dissipation of the chip; the opening design is reasonably performed on the inflatable phase change device, so that a better air flow channel is formed inside the router, so that the external cold air can enter the inside of the router, and the cold air can conduct convection heat exchange with the internal device, and the internal heat is exported to the outside air to achieve the effect of heat dissipation. Therefore, the heat of the chip on the PCB board of the electronic device is transferred to the heat dissipation system through heat conduction, and the setting of the air flow channel enables the heat of the inflatable phase change device to be transferred to the outside through convection heat exchange, so as to effectively reduce the chip temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an overall exploded view of the router according to the first embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram of the air flow channel of the router according to the first embodiment of the present invention.

[0031] Figure 3 This is a thermal resistance network diagram of the router of the first embodiment provided by the present invention.

[0032] Figure 4 It is a schematic diagram of fluid velocity distribution near the wall surface of Example 1 provided by the present invention.

[0033] Figure 5 It is a schematic diagram of a side of an upward-blowing phase change device provided by the present invention that is not in contact with a PCB board.

[0034] Figure 6 It is a schematic diagram of the side of the bottom-blowing phase change device provided by the present invention that is not in contact with the PCB board.

[0035] Figure 7 yes Figure 6 Schematic diagram of the contact surface between the bottom-blowing phase change device and the PCB board.

[0036] Figure 8 yes Figure 7 Partial schematic diagram of A in the figure.

[0037] Fig. 9 It is an arrangement structure of an array of adjacent support columns provided by the present invention.

[0038] Fig.10 This is another arrangement structure of the adjacent support column array provided by the present invention.

[0039] The reference numerals in the accompanying drawings are:

[0040] 101. first outer shell; 102. first heat spreader; 103. screen cover; 104. first thermal pad; 105. chip; 106. PCB board; 107. second thermal pad; 108. second heat spreader; 109. second outer shell; 201. positioning member; 202. island through hole; 203. island; 204. flow channel; 205. reinforcing rib; 206. threaded hole; 207. substrate. DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "set", "install", "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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The present invention will be further described below in conjunction with the accompanying drawings.

[0044] Embodiment 1

[0045] like Figure 1As shown, the heat dissipation system provided by the present invention has the inflatable phase change device provided by the present invention. The heat dissipation system is applied to a router. The router is composed of a first shell 101, a PCB board 106 and a second shell 109 from top to bottom. A chip 105 is arranged above the PCB board 106. The heat dissipation system includes a first heat spreader 102 and a first thermally conductive pad 104 which are sequentially located below the first shell 101. A screen cover 103 is arranged between the first heat spreader 102 and the first thermally conductive pad 104. The heat dissipation system also includes a second thermally conductive pad 107 which is sequentially located below the PCB board 106. and the second heat spreader 108, the second shell 109 of the router is located below the second heat spreader 108, the first and second heat spreaders are both inflation-type phase change devices, and the inflation-type phase change device is a special chip heat dissipation device, which has the effect of temperature uniformity and avoids temperature concentration; the screen cover 103 protects the electronic devices; the material of the first and second thermal conductive gaskets selects silicone as the basic material, adds certain metal oxides and various thermal conductive auxiliary materials, and is then made of synthetic materials through a special process, which reduces the contact thermal resistance generated between the heat source surface and the contact surface of the heat dissipation device, and fills the gap between the contact surfaces very well.

[0046] The inflation type phase change device is divided into an upper inflation type phase change device and a lower inflation type phase change device according to the position on the PCB board 106. Figure 5 As shown, it is an upward-blowing phase change device, which is placed above the PCB board 106, and the chip 105 is located above the PCB board 106; Figures 6 to 8 As shown, it is a bottom-blowing type phase change device, which is provided with positioning members 201 and reinforcing ribs 205 around it. The bottom-blowing type phase change device is placed under the PCB board 106. Figure 8 The threaded hole 206 is shown. The threaded hole 206 is used to install a screw. The screw is used to connect the PCB board and the blown phase change device to reduce contact thermal resistance.

[0047] like Fig. 9 , the two adjacent groups of support column arrays of the inflation-type phase change device are arranged neatly, and the adjacent islands are staggered at an angle of 90°; Fig.10 The two adjacent groups of support column arrays of the inflation-type phase change device are staggered, and the staggered angle between adjacent islands is 60°.

[0048] like Figure 5The upper inflatable phase change device includes a substrate 207, and a positioning member 201 and a threaded hole 206 are arranged around the substrate 207. The substrate 207 is inflated to form a flat cavity, and the cavity is filled with a refrigerant after vacuum treatment; a plurality of islands 203 arranged in an array are arranged between the upper and lower walls of the cavity on the substrate 207, and the cavity around the islands 203 forms a flow channel 204; an island through hole 202 is provided in the island 203 on the first heat spreader 102, where the projections of the screen 103 and the island 203 on the plane where the substrate 207 is located do not overlap; and an island through hole 202 is provided in the island 203 on the second heat spreader 108 that is not in contact with the second thermal pad 107. The function of the island through hole 202 is to allow air to circulate so as to transfer heat.

[0049] The heat transfer path is as follows:

[0050] like Figures 1-2 As shown, it is to show the air flow channel transmission path. Figure 2 In the figure, some components are omitted. The chip 105 of the router is the heat source of the router. The heat generated by the power of the chip is transferred upward to the first thermal pad 104, the heat of the first thermal pad 104 is transferred to the screen 103, the heat of the screen 103 is transferred to the first heat spreader 102, the heat of the first heat spreader 102 is convected with the air, and the hot air flows out of the router to the outside through the first shell 101; the heat generated by the heat of the chip 105 is also transferred downward to the PCB board 106, the heat of the PCB board 106 is transferred to the second thermal pad 107, the heat of the second thermal pad 107 is transferred to the second heat spreader 108, the heat of the second heat spreader 108 is transferred to the air by heat convection, and the hot air and the second shell 109 are transferred to the outside.

[0051] In this embodiment, the process of cold air in the router passing through the heat dissipation system is as follows: cold air enters the interior of the router from the circulation hole of the second shell 109 below, a part of the cold air performs convection heat exchange with the second heat spreader 108, and another small part directly enters the PCB board 106 from the flow channel 204, and a small part of the cold air performs convection heat exchange with the PCB board 106. The size of the first heat spreader 102 is relatively large, and the external cold air can directly flow in through the second shell 109 below, and directly perform convection heat exchange with both sides of the first heat spreader 102. A part of the hot air flows out from the side of the first heat spreader 102, and another part flows into the interior of the first heat spreader 102 for convection heat exchange, and flows out from the island through hole 202 of the first heat spreader 102. A part of the hot air inside the router flows to the outside from the side of the second shell 109 below, and another part flows out from the first shell 101 above. The heat generated by the chip 105 is transferred to the heat dissipation system and the PCB board 106 through heat conduction, and both of the inflatable phase change plates are in contact with the cold air. The second heat spreader 108 has reasonable openings to allow cold air to contact the PCB board 106, so that the first heat spreader 102, the second heat spreader 108 and the PCB board 106 can all perform convection heat exchange with the cold air to transfer heat to the external environment, thereby achieving the effect of reducing the temperature of the chip 105.

[0052] The inside of the inflatable phase change device is first vacuum treated, and then the liquid working medium refrigerant is injected. The refrigerant as the working medium vaporizes at the heat source position to absorb heat, and liquefies and releases heat in the area outside the heat source, realizing the process of gas-liquid phase change. The thermal conductivity of the inflatable phase change device is dozens of times higher than that of the aluminum plate, which effectively improves the temperature uniformity effect and avoids the hot spot concentration phenomenon; the inflatable phase change device has a surface thermal functional structure on the inflated side. This structure theoretically has the effect of inducing turbulence, can disturb the flow boundary layer and increase the specific surface area, and has the effect of enhancing the heat dissipation effect; compared with the aluminum plate, the inflatable phase change device can increase the temperature uniformity effect and improve the heat dissipation energy reasonably, so it is beneficial to reduce the chip temperature.

[0053] Most of the electronic components of the router are located on the PCB board. The first heat spreader adopts an inflated structure shape, which is not easy to fit the upper surface of the PCB board. There are fewer electronic components under the PCB board, and the lower part of the PCB board fits with the second heat spreader, which also adopts an inflated phase change device. The structure of the second heat spreader is easier to manufacture than the first heat spreader.

[0054] The island 203 and the flow channel 204 of the inflation-type phase change device provided by the present invention should not exceed 6mm to achieve the effect of uniform temperature. The second heat spreader and the PCB are connected and heat transferred by a thermally conductive gasket. The other end of the second thermally conductive gasket in contact with the second heat spreader should be distributed with the position of the island, which is more conducive to heat transfer. The height of the second heat spreader placed against gravity should not be too high, and the inflation height of the second heat spreader is 0.8 to 1mm. There is a working medium between the island and the flow channel of the second heat spreader, and the island and the flow channel are relatively small. The inflation-type phase change device is also conducive to gas-liquid phase change under reverse gravity and thus achieves the effect of uniform temperature.

[0055] There are electronic devices between the second heat spreader and the lower surface of the PCB board, and protruding reinforcing ribs 205 are punched around the inflatable phase change device to prevent the second heat spreader from contacting and damaging the electronic devices.

[0056] The second vapor chamber and the first vapor chamber both adopt direct cooling, that is, direct cooling by refrigerant, and the working medium thereof is refrigerant.

[0057] There are a few raised positioning pieces 201 on the side of the second heat spreader to achieve the purpose of positioning and facilitate assembly and disassembly. The threaded holes 206 of the second heat spreader adopt a flanging process, which is conducive to fixing the PCB board 106 and the inflatable phase change device with screws. The internal space of the router is limited, and the thickness of the substrate of the second heat spreader is 1.5mm.

[0058] In the router based on the inflation-type phase change device, the router chip temperature is set to T b , the external environment temperature is T a The total power emitted by the chip is Q, and the total thermal resistance is R, then:

[0059]

[0060] The total power Q of the chip remains unchanged while the external temperature T a If the chip temperature T b To reduce it, the total thermal resistance R needs to be reduced. Figure 3 , let the gasket thermal resistance be R1, the barrier thermal resistance be R2, the upper aluminum plate thermal resistance be R3, the air thermal resistance be R4, the upper shell thermal resistance be R5, the PCB thermal resistance be R6, the inflatable phase change device be R7, and the lower shell be R8, then we can get

[0061]

[0062] The above formula shows that when the total power and ambient temperature remain unchanged, the temperature of the chip can be reduced by reducing the size of the overall thermal resistance. Due to the high thermal conductivity of the heat spreader, the heat spreader size is designed and holes are opened at reasonable positions to improve the convective heat transfer coefficient. Therefore, the phase change device of the inflatable heat spreader used in the present invention is used as a heat sink for the chip and the size structure is reasonably designed to dissipate heat from the router. The interior of the inflatable phase change device is in a vacuum state. The refrigerant as the working medium vaporizes and absorbs heat at the heat source position, and releases heat in the area outside the heat source, achieving a phase change heat transfer effect, thereby achieving a temperature uniformity effect on the entire plane of the inflatable phase change device, which is part of the reason why the thermal conductivity of the inflatable phase change device is very high.

[0063] The thermal resistance of a material is mainly related to the thermal conductivity of the material. The thermal conductivity of the inflatable phase change device is 5000W / (m·K), and the thermal conductivity of the 1000 series aluminum is 222W / (m·K). The thermal conductivity of the inflatable phase change device is about 22 times that of aluminum alloy. Therefore, the thermal conductivity of the inflatable phase change device is lower than the thermal resistance of aluminum. The reduction in thermal resistance reduces the overall thermal resistance. Since the chip power remains unchanged, the temperature of the chip is reduced at the same ambient temperature. The inflatable phase change device has a small groove (surface thermal functional structure) on the inflated side. This structure theoretically has the ability to induce turbulence, disturb the flow boundary layer and increase the specific surface area, so it has the effect of enhancing the heat dissipation effect.

[0064] The cold air circulation mostly flows in from the lower surface of the second shell 109 below. In order to achieve a better convective heat transfer effect, the overall structure of the upper inflation-type phase change device is larger than the lower device, so that the heat dissipation system can be in direct contact with the external cold air, and has a better convective heat transfer effect.

[0065] The inflatable part of the inflatable phase change device has islands and flow channels. The starting section of the island needs to re-induce the boundary layer. The thickness of the boundary layer is smaller at the starting position, and the convective heat transfer coefficient increases. The concave island of the inflatable phase change device can re-induce the boundary layer and disturb the boundary layer. The starting position of the boundary layer is the smallest, such as Figure 4 The heat exchange capacity between the material and the air here is the highest, and the concave island can re-trigger the boundary layer, which improves the convection heat transfer coefficient and is beneficial to the heat dissipation of the chip.

[0066] The fluid boundary layer refers to the situation where the velocity of the fluid increases sharply as the distance y increases when the fluid flows through a flat plate. After passing through a thin layer, the velocity of the fluid approaches the mainstream velocity. This thickness is the boundary layer thickness. The thickness of the boundary layer of the fluid at the beginning of the flat plate is the thinnest. As the distance x increases, the boundary layer gradually thickens due to the influence of the viscous force. The thermal boundary layer refers to the situation where the temperature of the fluid changes dramatically in the normal direction of the wall. Outside this thin layer, the temperature gradient of the fluid is almost zero. This thin layer is the thermal boundary layer. The thickness of the thermal boundary layer of air is roughly the same as that of the fluid boundary layer. The thicker the thermal boundary layer, the longer the distance that the hot air enters the cold environment. That is, the thicker the thermal boundary layer, the less likely it is to release heat energy. Therefore, the convective heat transfer coefficient is related to the thickness of the thermal boundary layer. The thinner the thermal boundary layer, the greater the convective heat transfer coefficient, and the larger the thermal boundary layer, the smaller the convective heat transfer coefficient. Therefore, the thicker the air-fluid boundary layer, the less conducive it is to heat dissipation, and the thinner the air-fluid boundary layer, the more conducive it is to heat dissipation. The flow channel and island arrangement of the inflation-type phase change device can re-induce the boundary layer and disturb the boundary layer, thereby improving the convective heat transfer coefficient and facilitating the heat dissipation of the object.

[0067] Chip 105 is distributed above PCB board 106 of the router, and chip 105 is protected by screen cover 103. Chip 105, PCB board 106, and first heat spreader 102 are connected by first thermal pad 104. The bottom of PCB board 106 is connected to second thermal pad 107 and second heat spreader 108. Island through hole 202 is opened at the island 203 position of first heat spreader 102. The size structure of first heat spreader 102 is larger than that of second heat spreader. When cold air flows into the router from below second shell 109, the cold air can have convective heat exchange effect with first heat spreader 102 and second heat spreader 108 inside the router. Airflow can flow out from around the first heat spreader and the island opening, and hot air flows out of the first shell to the outside. After the temperature of chip 105 is transferred to the first and second heat spreaders, heat exchange is performed with cold air, and heat is introduced into the outside through the flow of air, so as to achieve the effect of reducing the temperature of the chip. Compared with the heat sinks used in the market that use aluminum sheets or aluminum fins as heat sinks, the heat dissipation system of the present invention uses a heat sink phase change device with high heat conduction and heat distribution, which can better avoid the phenomenon of hot spot concentration, and the flow channel design is further optimized compared with the existing technology to achieve effective heat dissipation. The present invention can be used not only in low-power routers but also in higher-power router systems.

[0068] The electronic device provided by the present invention adopts the above-mentioned inflatable phase change device to dissipate heat. The above-mentioned inflatable phase change device has a high thermal conductivity and can achieve a better temperature uniformity effect. At the same time, the inflatable phase change device has a surface thermal functional structure, which can induce turbulence and break the boundary layer to enhance the heat dissipation effect. In view of the above two points, the overall heat dissipation efficiency can be improved, the temperature of the chip can be reduced, and the performance of the terminal device can be better. Therefore, in the same heat dissipation space, compared with traditional heat dissipation, the present invention has a better heat dissipation effect.

[0069] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A blown phase change device, characterized in that: The invention comprises a base plate (207), wherein the inside of the base plate (207) is inflated to form a flat cavity; a plurality of inwardly concave support columns are arranged between the upper and lower walls of the cavity of the base plate (207); the upper and lower outer surfaces of the support columns form an isolated island (203); the cavity around the isolated island (203) forms a flow channel (204); the flow channel (204) is filled with a refrigerant for heat dissipation after vacuum treatment; the flow channel (204) and the isolated island (203) form an uneven surface thermal functional structure; the base plate (207) is provided with threaded holes (206) for fixing; the inflation height of the base plate (207) does not exceed 1 mm; the size of the flow channel (204) does not exceed 6 mm; the size of the isolated island (203) The size does not exceed 6 mm; a heat-conducting pad for heat conduction is provided between the inflation-type phase-change device and a PCB board (106) that needs to dissipate heat; a screen cover (103) is provided below the inflation-deformation device located on the upper part of the PCB board (106); an island through hole (202) is provided in the island (203) of the inflation-deformation device located on the upper part of the PCB board (106) at a position where the projections of the screen cover (103) and the island (203) on the plane where the substrate (207) are located do not overlap; and an island through hole (202) is provided in the island (203) of the inflation-deformation device located on the lower part of the PCB board (106) at a position that does not contact the heat-conducting pad.

2. The inflation-type phase change device according to claim 1, characterized in that: The base plate (207) is provided with a plurality of protrusions around its edges to form reinforcing ribs (205).

3. The inflation-type phase change device according to claim 1, characterized in that: The threaded hole (206) of the base plate (207) is formed by a flanging process.

4. The inflation-type phase change device according to claim 1, characterized in that: The side edge of the base plate (207) is provided with a positioning piece (201) for locking and positioning.

5. The inflation-type phase change device according to claim 1, characterized in that: The sum of the thickness of the upper wall and the lower wall of the base plate (207) does not exceed 1.5 mm.

6. The inflation-type phase change device according to claim 1, characterized in that: The array of support columns in each row constitutes a group, and the arrays of two adjacent groups of support columns are arranged in a staggered manner, and the staggered angle between adjacent isolated islands (203) is 60°.

7. An electronic device comprising the inflatable phase change device according to any one of claims 1 to 6, characterized in that: The invention comprises a first shell (101), a screen cover (103), the PCB board (106) and a second shell (109) which are arranged in sequence from top to bottom; the inflation-type phase change device is arranged between the first shell (101) and the PCB board (106) and / or between the PCB board (106) and the second shell (109).

8. The electronic device according to claim 7, characterized in that: The inflatable phase change device is a heat spreader, wherein the inflatable phase change device located above the PCB board (106) is a first heat spreader (102), and the inflatable phase change device located below the PCB board (106) is a second heat spreader (108); the first heat spreader (102) is arranged below the first housing (101) and is located on the screen cover (103); a first thermal conductive pad (104) for heat conduction is arranged below the screen cover (103); and the PCB board (106) is located below the first thermal conductive pad (104); the second heat spreader (108) is arranged above the second housing (109) and is covered with a second thermal conductive pad (107); the second thermal conductive pad (107) is located below the PCB board (106).

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