Cooling fin capable of inhibiting electromagnetic radiation emission

Abstract

The invention is applicable to the field of network communication, and provides a radiating fin capable of inhibiting electromagnetic radiation emission, which is applied to a printed circuit board (PCB) provided with a heating element and comprises a radiating fin made of a high-conductivity metal material, and the radiating fin covers a radiation source area on the PCB. The radiating fin is electrically connected with the grounding layer of the PCB through the grounding structure, so that the radiating fin can be used as a shielding body for suppressing electromagnetic radiation while radiating heat, efficient radiating of the electronic equipment and effective suppression of electromagnetic radiation emission are realized on the premise that hardware cost is not remarkably increased, 30M-1GHz frequency band radiation meets EN55032 certification specifications, and the radiating fin can be used as a shielding body for suppressing electromagnetic radiation. And the working temperature of each device is within an allowable range.

Description

Technical Field

[0001] This invention relates to the field of network communication, specifically to a heat sink that can suppress electromagnetic radiation emission. Background Technology

[0002] In conventional electronic devices that use heat sinks, the traditional design approach has obvious flaws: on the one hand, heat sinks can only solve the heat dissipation problem of electronic devices, but do not help to suppress electromagnetic radiation. Some poorly designed heat sinks may even introduce additional electromagnetic radiation. On the other hand, adding additional suppression devices such as shielding covers to solve the electromagnetic radiation problem will not only increase costs, but also have the opposite effect on the heat dissipation of the product.

[0003] In existing technologies, efficient heat dissipation and the requirements for electromagnetic compatibility (EMC) radiation emission are contradictory, and it is difficult to achieve synergistic optimization of both without significantly increasing hardware costs. Therefore, there is an urgent need to provide a heat sink that can suppress electromagnetic radiation emission to overcome the shortcomings in current practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide a heat sink that can suppress electromagnetic radiation emission, thereby solving the problems mentioned in the background art.

[0005] The present invention is implemented as follows: a heat sink that can suppress electromagnetic radiation emission is applied to a printed circuit board (PCB) on which heat-generating elements are mounted. The heat sink is made of a highly conductive metal material, and the heat sink covers the radiation source area on the PCB. The heat sink is electrically connected to the ground layer of the PCB through a grounding structure, so that the heat sink can also serve as a shield to suppress electromagnetic radiation while dissipating heat.

[0006] As a further aspect of the present invention: the highly conductive metal material is highly conductive aluminum.

[0007] As a further aspect of the present invention, the surface of the heat sink has a conductive surface treatment layer.

[0008] As a further aspect of the present invention: the conductive surface treatment layer is a conductive anodic oxide coating.

[0009] As a further aspect of the present invention: the grounding structure includes a plurality of fixing screws, and the heat sink has a plurality of fixing holes for mounting the fixing screws. The heat sink is fixedly connected to the PCB by the fixing screws, and the electrical connection with the ground layer of the PCB is achieved by the fixing screws. As a further aspect of the present invention: the area where the heat sink contacts the PCB via fixing screws is provided with a grounding pad with exposed copper and tin.

[0010] As a further aspect of the present invention, the grounding structure further includes a conductive and thermally conductive pad disposed between the heat sink and other shielding covers on the PCB.

[0011] As a further aspect of the present invention: the conductive and thermally conductive pad is a graphite-filled silicone pad.

[0012] As a further aspect of the present invention: the heat sink is provided with heat dissipation teeth, and the edges and tips of the heat dissipation teeth are chamfered or rounded.

[0013] As a further aspect of the present invention: the physical length of any cantilever structure on the heat sink is less than one-quarter of the wavelength of the preset interference frequency in air.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention combines heat sink design with electromagnetic shielding function, using a large-area metal heat sink with good grounding as a local shield. While meeting heat dissipation requirements, it effectively suppresses electromagnetic radiation, avoiding the cost and negative impact of adding additional shielding devices, and achieving synergistic optimization of heat dissipation and electromagnetic compatibility. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0017] Figure 2 This is a side view of the structure of the present invention.

[0018] Figure 3 This is a graph showing measured data of electromagnetic radiation emission.

[0019] In the attached diagram: 1-Heat sink, 2-Fixing hole, 3-Conductive surface treatment layer. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] The present invention will be further explained below with reference to specific embodiments.

[0024] Please see Figures 1-3 The present invention provides a heat sink that can suppress electromagnetic radiation emission, which is applied to a printed circuit board (PCB) on which a heat-generating element is installed. It includes a heat sink 1 made of a highly conductive metal material. The heat sink 1 covers the radiation source area on the PCB, and the heat sink is electrically connected to the ground layer of the PCB through a grounding structure, so that the heat sink can also serve as a shield to suppress electromagnetic radiation while dissipating heat.

[0025] The heat sink 1 is provided with heat dissipation teeth, and the edges and tips of the heat dissipation teeth are chamfered or rounded. Highly conductive aluminum should be preferred for surface treatment, and conductive anodizing should be applied. Low-conductivity or insulating coatings (such as ordinary paint or ordinary anodizing) should be avoided.

[0026] A highly conductive surface reduces the high-frequency impedance of the heatsink 1 surface, making it easier for interference current to flow away through the grounding path and reducing the induced voltage difference between radiation sources. Conductive anodizing provides good conductivity while also ensuring corrosion resistance and insulation between the heatsink and the chip.

[0027] During the production process, it is necessary to ensure that the conductive coating is completely and evenly applied, especially at the edges of the heat dissipation fins.

[0028] In one embodiment of the present invention, please refer to Figures 1-2 The surface of the heat sink 1 has a conductive surface treatment layer 3; The conductive surface treatment layer 3 is a conductive anodic oxide coating.

[0029] In one embodiment of the present invention, please refer to Figures 1-2 The grounding structure includes multiple fixing screws, and the heat sink 1 has multiple fixing holes 2 for installing the fixing screws. The fixing screws are used to fix the structure to the PCB and to achieve electrical connection with the PCB grounding layer. The area where the heat sink 1 contacts the PCB via fixing screws is provided with an exposed copper and tinned grounding pad; The grounding structure also includes a conductive and thermally conductive pad disposed between the heat sink 1 and other shielding covers on the PCB; The conductive and thermally conductive pad is a graphite-filled silicone pad.

[0030] In one embodiment of the present invention, please refer to Figures 1-2 The physical length of any cantilever structure on the heat sink 1 is less than one-quarter of the wavelength of the preset interference frequency in air.

[0031] Optimize the spacing and shape of heatsink 1: Calculate the fundamental and harmonic frequencies of the main interference sources in electronic devices (such as clock and switching power supply frequencies) to ensure that the physical length of the longest cantilever structure on heat sink 1 is much less than 1 / 4 (λ / 4) of the wavelength of these frequencies in air. Sharp edges are efficient radiation sources. Chamfering or rounding the edges and tips of the heat dissipation teeth can effectively reduce electric field concentration and reduce radiation efficiency.

[0032] In an embodiment of the present invention, the heat sink 1 is used as a shield. Under the premise that space permits and heat dissipation requirements are met, the heat sink 1 is designed as part of a partial shield to cover the critical radiation source area.

[0033] A large, well-grounded metal plate itself acts as a shield. This invention uses a cost-effective aluminum plate and maximizes the size of the heat sink 1 to cover the IC that generates strong radiation and its surrounding high-speed circuits (such as clock lines and data lines). It ensures good overlap between the heat sink 1 and the PCB ground layer on all four sides, forming a localized "Faraday cage" effect.

[0034] Taking into account both the heat dissipation effect and the electromagnetic emission suppression effect of heat sink 1, highly conductive aluminum is preferred and a conductive surface treatment is applied. A conductive anodized coating is sprayed on the upper surface of heat sink 1, and a low-impedance, multi-point, short-path grounding connection is provided for heat sink 1.

[0035] In practical applications, this invention requires ensuring that the mounting gaps between the heat sink 1 and the heat-generating element, PCB, and housing are as small as possible and filled with conductive material. Gaps and slits can form "slot antennas," with narrow slits radiating more strongly at higher frequencies. When using thermal pads, ensure they fully fill the tiny gaps between the IC and the bottom of the heat sink 1. The gap between the heat sink 1 and the PCB (excluding the grounding pad area) should be minimized.

[0036] This invention utilizes a heat sink 1 as a shield. Under the premise that space permits and heat dissipation requirements are met, the heat sink 1 is designed as part of a partial shield to cover the critical radiation source area.

[0037] A large, well-grounded metal plate itself acts as a shield. This invention uses a cost-effective aluminum plate and maximizes the size of the heat sink 1 to cover the IC that generates strong radiation and its surrounding high-speed circuits (such as clock lines and data lines). It ensures good overlap between the heat sink 1 and the PCB ground layer on all four sides, forming a localized "Faraday cage" effect.

[0038] The heat dissipation effect of this invention was measured as follows: The equipment was fully operational. Thermocouples were attached to key chips and other nodes, and the equipment was run continuously for 3 hours. After the temperature reached a stable state, the temperature of the thermocouples at each node was recorded. All data were within the allowable operating temperature range of the device, and the test was passed. The test results are shown in Table 1.

[0039] Table 1. Results of heat dissipation performance test Actual measurement of electromagnetic radiation emission from equipment (reference) Figure 3 ): The equipment is placed in a microwave anechoic chamber, and all services are operational. The antenna receives the electromagnetic radiation emitted by the equipment, and the results are determined according to the CE certification standard EN55032.

[0040] Test conclusion: The test was passed. The measured radiation in the 30M~1GHz frequency band all met the requirements and had a margin.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat sink capable of suppressing electromagnetic radiation emission, applied to a printed circuit board (PCB) on which a heat-generating element is mounted, characterized in that, It includes a heat sink (1) made of a highly conductive metal material, which covers the radiation source area on the PCB and is electrically connected to the ground layer of the PCB through a grounding structure, so that the heat sink can both dissipate heat and act as a shield to suppress electromagnetic radiation.

2. The heat sink capable of suppressing electromagnetic radiation emission according to claim 1, characterized in that, The highly conductive metallic material is aluminum, a highly conductive metal.

3. The heat sink capable of suppressing electromagnetic radiation emission according to claim 1, characterized in that, The surface of the heat sink (1) has a conductive surface treatment layer (3).

4. The heat sink capable of suppressing electromagnetic radiation emission according to claim 3, characterized in that, The conductive surface treatment layer (3) is a conductive anodic oxide coating.

5. The heat sink capable of suppressing electromagnetic radiation emission according to claim 1, characterized in that, The grounding structure includes multiple fixing screws, and the heat sink (1) has multiple fixing holes (2) for installing the fixing screws. The heat sink (1) is fixedly connected to the PCB through the fixing screws, and the electrical connection with the grounding layer of the PCB is achieved through the fixing screws.

6. The heat sink capable of suppressing electromagnetic radiation emission according to claim 5, characterized in that, The area where the heat sink (1) contacts the PCB via fixing screws is provided with a grounding pad with exposed copper and tin.

7. The heat sink capable of suppressing electromagnetic radiation emission according to claim 6, characterized in that, The grounding structure also includes a conductive and thermally conductive pad disposed between the heat sink (1) and other shielding covers on the PCB.

8. The heat sink capable of suppressing electromagnetic radiation emission according to claim 7, characterized in that, The conductive and thermally conductive pad is a graphite-filled silicone pad.

9. The heat sink capable of suppressing electromagnetic radiation emission according to claim 1, characterized in that, The heat sink (1) is provided with heat dissipation teeth, and the edges and tips of the heat dissipation teeth are chamfered or rounded.

10. The heat sink capable of suppressing electromagnetic radiation emission according to claim 1, characterized in that, The physical length of any cantilever structure on the heat sink (1) is less than one-quarter of the wavelength of the preset interference frequency in air.

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