POS machine circuit board structure

Abstract

This utility model discloses a POS machine circuit board structure, including a board body and a chip. The chip is electrically connected to the board body. A first insulating ink layer and a second insulating ink layer are respectively stacked on both sides of the board body. It also includes an electrostatic shielding film, which covers the outside of the chip. A first adhesive layer is provided on the first insulating ink layer, surrounding the chip to bond and fix the edge of the electrostatic shielding film. A second adhesive layer is provided in the area where the electrostatic shielding film contacts the chip's outer shell. Thermally conductive silicone particles are provided on the second adhesive layer to fill the gap between the electrostatic shielding film and the chip's outer shell. This utility model provides anti-static treatment to the chip by covering it with an electrostatic shielding film. The electrostatic shielding film itself can act as a heat diffusion layer, and together with the thermally conductive silicone particles, it can construct an efficient heat dissipation channel of "chip-particle-film," suitable for chips with high heat generation.

Description

Technical Field

[0001] This utility model relates to the field of circuit board processing technology, specifically to a POS machine circuit board structure. Background Technology

[0002] As electronic payment terminals, POS machines are frequently used by people. Static electricity from the human body (up to several thousand volts) and static electricity from friction with the equipment can easily be conducted to the chips on the circuit board, damaging the delicate circuits inside the chips (such as the encryption module of the security chip and the logic unit of the CPU). Therefore, it is necessary to perform anti-static treatment on the chips of the POS machine circuit board.

[0003] The conventional anti-static treatment for chips on POS machine circuit boards involves coating the chip casing with anti-static insulating varnish. However, this varnish has the disadvantage of being thick (greater than 0.2 mm after drying) and having a low thermal conductivity, which affects chip heat dissipation and makes it unsuitable for use on chips that generate a lot of heat (such as CPUs). Utility Model Content

[0004] The purpose of this utility model is to provide a POS machine circuit board structure.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A POS machine circuit board structure includes a board body and a chip. The chip is electrically connected to the board body. A first insulating ink layer and a second insulating ink layer are respectively stacked on both sides of the board body. The circuit board also includes an electrostatic shielding film. The electrostatic shielding film covers the outside of the chip. A first adhesive layer is provided on the first insulating ink layer. The first adhesive layer surrounds the chip to bond and fix the edge of the electrostatic shielding film.

[0007] The electrostatic shielding film has a second adhesive layer in the area where it is attached to the chip's outer shell. The second adhesive layer has thermally conductive silicone particles to fill the gap between the electrostatic shielding film and the chip's outer shell.

[0008] As a further improvement of this utility model, the electrostatic shielding film is a polyimide film.

[0009] As a further improvement of this utility model, the thermally conductive silicone particles are distributed in a matrix on the second adhesive layer.

[0010] As a further improvement of this utility model, the thermally conductive silicone particles are spherical particles with a diameter of 0.01-0.03 mm.

[0011] As a further improvement of this utility model, both the first adhesive layer and the second adhesive layer are made of high-temperature curing adhesive.

[0012] As a further improvement of this utility model, the thickness of the electrostatic shielding film is 0.05-0.1 mm.

[0013] As a further improvement of the present invention, the invention also includes a heat-conducting pillar and a heat-conducting layer. The heat-conducting layer is stacked on the side of the second insulating ink layer away from the main body of the board. One end of the heat-conducting pillar contacts the back of the chip, and the other end of the heat-conducting pillar contacts the heat-conducting layer.

[0014] Compared with the prior art, the technical advantages of this utility model are as follows:

[0015] This invention provides anti-static treatment to the chip by coating it with an electrostatic shielding film. Compared to anti-static insulating varnish, the electrostatic shielding film is naturally easier to make thinner. The thinner electrostatic shielding film not only provides anti-static protection but also helps improve the chip's heat dissipation performance. Furthermore, the electrostatic shielding film can also cover the chip's pins, resulting in a better anti-static effect.

[0016] The electrostatic shielding film itself can serve as a heat diffusion layer. Combined with thermally conductive silicone particles, it can construct an efficient heat dissipation channel of "chip-particle-film," suitable for chips that generate a large amount of heat. At the same time, the thermally conductive silicone particles can fill in the small unevenness on the surface of the chip casing, preventing the formation of small gaps on the contact surface between the electrostatic shielding film and the chip casing, which would affect heat dissipation.

[0017] By adding heat-conducting layers and heat-conducting pillars, the heat dissipation performance of the chip can be further improved. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of a POS machine circuit board structure according to a specific embodiment of this utility model;

[0019] Figure 2 yes Figure 1 A magnified structural diagram of point A in the middle. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present invention.

[0021] Please see Figures 1 to 2A POS machine circuit board structure includes a board body 1 and a chip 2. The chip 2 is electrically connected to the board body 1. A first insulating ink layer 3 and a second insulating ink layer 4 are respectively stacked on both sides of the board body 1. It also includes an electrostatic shielding film 5, which covers the outside of the chip 2. A first adhesive layer 6 is provided on the first insulating ink layer 3. The first adhesive layer 6 surrounds the chip 2 to bond and fix the edge of the electrostatic shielding film 5.

[0022] The electrostatic shielding film 5 has a second adhesive layer 7 in the area where it is attached to the outer shell of the chip 2. The second adhesive layer 7 has thermally conductive silicone particles 9 to fill the gap between the electrostatic shielding film 5 and the outer shell of the chip 2.

[0023] The main body 1 has a common circuit board layer structure, including a substrate layer and a wiring layer.

[0024] The electrostatic shielding film 5 is set on the outside of the chip 2, which means that the electrostatic shielding film 5 covers both the outer shell and the pins of the chip 2 inside. Compared with the existing technology that only coats the outer shell of the chip 2 with antistatic insulating paint, the electrostatic shielding film 5 also covers the pins, which has a better antistatic effect.

[0025] The first adhesive layer 6 is distributed in a ring shape, avoiding the pin pads of chip 2 to prevent pad contamination.

[0026] It should be noted that the most common chip 2 casing is made of plastic. During injection molding, the mold surface itself has micron-level roughness (to prevent the plastic part from sticking to the mold, the mold needs slight sandblasting), which is directly "replicated" onto the plastic part surface. Furthermore, uneven cooling rates during the flow of molten plastic within the mold can lead to localized shrinkage differences, forming tiny depressions (such as near "weld marks"). These minor unevennesses on the chip 2 casing prevent the electrostatic shielding film 5 from adhering smoothly to the chip 2 casing, creating small gaps between them. The poor thermal conductivity of air significantly reduces the heat dissipation performance of the chip 2. However, by filling with thermally conductive silicone particles 9, the heat generated by the chip 2 can be directly conducted to the electrostatic shielding film 5. Comparative tests show that the interfacial thermal resistance (between chip 2 and the film) of this structure can reach 0.8℃·cm. 2 / W, lower than traditional insulating varnish (1.5℃·cm). 2 / W).

[0027] Furthermore, the electrostatic shielding film 5 is a polyimide film. Polyimide film has good electrostatic protection performance and high temperature resistance, making it suitable for electrostatic protection of the high-heat-generating chip 2 on the POS machine circuit board.

[0028] Furthermore, the thermally conductive silicone particles 9 are distributed in a matrix on the second adhesive layer 7. The thermally conductive silicone particles 9 are prepared on the second adhesive layer 7 using a dispensing machine.

[0029] The thermally conductive silicone particles 9 are preferably low-temperature softening thermally conductive silicone particles 9 (existing materials) using an addition-type silicone system. The softening temperature of the thermally conductive silicone particles 9 is lower than the maximum temperature resistance temperature of the chip 2 (usually around 120 degrees Celsius). When attaching the electrostatic shielding film 5, the thermally conductive silicone particles 9 can be softened and deformed by heating, thereby enabling the thermally conductive silicone particles 9 to better fill the small uneven areas of the chip 2's outer shell.

[0030] Furthermore, the thermally conductive silicone particles 9 are spherical particles with a diameter of 0.01-0.03 mm.

[0031] The spherical particles have good flowability. During the application of the electrostatic shielding film 5, before the first adhesive layer 6 and the second adhesive layer 7 are cured at high temperature, the electrostatic shielding film 5 can be made to vibrate at high frequency and small amplitude relative to the chip 2 using a vibration device. This causes the thermally conductive silicone particles 9 to move and embed into the small recesses on the chip 2's outer shell. The diameter range of the thermally conductive silicone particles 9 is roughly the same as the size range of the small recesses on common plastic chip outer shells.

[0032] Furthermore, both the first adhesive layer 6 and the second adhesive layer 7 are made of high-temperature curing adhesive.

[0033] The high-temperature curing adhesive has low viscosity at room temperature, which makes it easy to adjust the attachment position of the electrostatic shielding film 5. After adjustment, it can be firmly attached to the outside of the chip 2 by heating and curing.

[0034] Furthermore, the thickness of the electrostatic shielding film 5 is 0.05-0.1 mm.

[0035] Furthermore, it also includes a heat-conducting pillar 8 and a heat-conducting layer 10. The heat-conducting layer 10 is stacked on the side of the second insulating ink layer 4 away from the board body 1. One end of the heat-conducting pillar 8 is in contact with the back of the chip 2, and the other end of the heat-conducting pillar 8 is in contact with the heat-conducting layer 10.

[0036] Both the heat-conducting pillar 8 and the heat-conducting layer 10 are made of copper. The heat generated by the chip 2 during operation is guided to the heat-conducting layer 10 for dissipation through the heat-conducting pillar 8, which can further reduce the operating temperature of the chip 2.

[0037] Compared with the prior art, the technical advantages of this utility model are as follows:

[0038] This invention provides anti-static treatment for chip 2 by covering it with an electrostatic shielding film 5. Compared with anti-static insulating varnish, the electrostatic shielding film 5 is naturally easier to make thinner. The thinner electrostatic shielding film 5 not only provides anti-static protection but also helps improve the heat dissipation performance of chip 2. Furthermore, the electrostatic shielding film 5 can also cover the pins of chip 2, resulting in better anti-static effect.

[0039] The electrostatic shielding film 5 itself can serve as a heat diffusion layer. Combined with the thermally conductive silicone particles 9, it can construct an efficient heat dissipation channel of "chip 2-particle-film", which is suitable for chips 2 that generate a lot of heat. At the same time, the thermally conductive silicone particles 9 can fill the small bumps on the surface of the chip 2 shell, preventing the formation of small gaps on the contact surface between the electrostatic shielding film 5 and the chip 2 shell, which would affect heat dissipation.

[0040] By setting up the heat-conducting layer 10 and the heat-conducting pillars 8, the heat dissipation performance of the chip 2 can be further improved.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although this utility model 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of this utility model.

Claims

1. A POS machine circuit board structure, comprising a board body and a chip, wherein the chip is electrically connected to the board body, and a first insulating ink layer and a second insulating ink layer are respectively stacked on both sides of the board body, characterized in that, It also includes an electrostatic shielding film, which is disposed over the outside of the chip. A first adhesive layer is provided on the first insulating ink layer, which surrounds the chip to bond and fix the edge of the electrostatic shielding film. The electrostatic shielding film has a second adhesive layer in the area where it is attached to the chip's outer shell. The second adhesive layer has thermally conductive silicone particles to fill the gap between the electrostatic shielding film and the chip's outer shell.

2. The POS machine circuit board structure according to claim 1, characterized in that, The electrostatic shielding film is a polyimide film.

3. The POS machine circuit board structure according to claim 1, characterized in that, The thermally conductive silicone particles are distributed in a matrix on the second adhesive layer.

4. The POS machine circuit board structure according to claim 1, characterized in that, The thermally conductive silicone particles are spherical particles with a diameter of 0.01-0.03 mm.

5. The POS machine circuit board structure according to claim 1, characterized in that, Both the first adhesive layer and the second adhesive layer are made of high-temperature curing adhesive.

6. The POS machine circuit board structure according to claim 1, characterized in that, The thickness of the electrostatic shielding film is 0.05-0.1 mm.

7. The POS machine circuit board structure according to claim 1, characterized in that, It also includes a heat-conducting pillar and a heat-conducting layer. The heat-conducting layer is stacked on the side of the second insulating ink layer away from the main body of the board. One end of the heat-conducting pillar contacts the back of the chip, and the other end of the heat-conducting pillar contacts the heat-conducting layer.

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