TWI365017B - Printed circuit board - Google Patents

Description

1365017 » I

[0001] [0002] [0003] 100 years, 13 months, revised replacement, 100 inventions: [Technical Field] The present invention relates to a printed circuit board. [Prior Art] Printed circuit boards have a wide range of applications in the electronics industry. When printed circuit boards are used, due to interference between electronic components, a large amount of broadband noise or noise is often generated by the interference current, which seriously affects the function of the printed circuit board. This phenomenon is generally referred to as Electro Magnetic Inter-ference (EM I ). In order to reduce the electromagnetic interference of the printed circuit board during use, it is usually necessary to direct the current causing electromagnetic interference to the earth. In general, a through hole is formed in the printed circuit board. A screw is passed through the through hole and screwed onto a housing that is electrically connected to the ground to shield the interference current on the printed circuit board by the screw. And the housing is oriented to the ground. A copper plating layer is generally disposed on the surface of the printed circuit board around the through hole, and the current on the printed circuit board flows through the copper plating layer when the current flows to the ground, and the copper plating layer is easily oxidized by the air, which is disadvantageous for the printed circuit board. Current is derived. Therefore, a layer of solder paste is usually applied on the copper plating layer around the through hole, and then the solder paste is better attached to the copper plating layer through the tin furnace. However, when passing through the tin furnace, the solder paste easily flows into the through hole to form a sealing hole. problem. In order to prevent the sealing problem from occurring in the prior art, the through hole is sealed by the tape before the printed circuit passes through the tin furnace. However, the tape is extremely wasteful of time, and usually requires an increase in manpower, thereby increasing the production cost. . SUMMARY OF THE INVENTION In view of the above situation, it is necessary to provide a short processing time and low cost 097124123 Form No. A0101 Page 3 / Total 14 Page 1003376132-0 [0004] 1365017 October 13, 100 Nuclear Positive_Page Printed Circuit board.

[0005] A printed circuit board includes a board body having a through hole formed therein, and the printed circuit board is fixedly connected to the grounding member by the through hole. The surface of the printed circuit board is provided with a tin plating layer around the through hole. The tin plating layer is in contact with the grounding member and the printed circuit board is electrically connected to the grounding member. The plate body comprises a first copper pig layer, a first steel plate layer, a ground layer, a second steel plate layer and a second copper foil layer. The first steel plate layer is provided with a plurality of first tin plates, and the plurality of first tin plates penetrate and protrude from the first copper foil layer. The second steel plate layer is provided with a plurality of second tin plates, the plurality of second tin plates penetrating and protruding from the second copper foil layer, the tin plating layer covering the second copper foil layer and the plurality of second tin plates . A solder resist for preventing the solder paste from flowing into the through hole is provided around the through hole.

[0006] Compared with the prior art, the soldering circuit is provided with solder resist around the through hole. When the printed circuit board passes through the tin furnace, the solder resist can prevent the solder paste from flowing into the printed circuit board. Prevent the problem of sealing. The application of solder-proofing around the via hole is simple and can effectively shorten the processing time, thereby reducing the production cost. [Embodiment] Hereinafter, a printed circuit board of the present invention will be described in further detail with reference to the accompanying drawings and preferred embodiments. Referring to FIG. 1 and FIG. 2, a printed circuit board 10 according to a preferred embodiment of the present invention includes a board body 12 and a circular through hole 14 and a plurality of via holes 16 formed in the board body 12, and a plurality of via holes 16 It is evenly distributed around the through hole 14. The printed circuit board 10 can be fixedly connected to the grounding component of the electronic device through the through hole 14, and the 097124123 maintains the printed circuit board 10 electrically connected to the ground. Form No. A0101 Page 4 of 14 1003376132-0 1365017 • . [0009]

Correction Replacement Page on October 13, 100 The board body 12 includes a first surface 122 and a second surface 124 opposite the first surface 122. A plurality of first tin plates 18 and a first copper foil layer 20 are disposed on the first surface 122 of the plate body 12 around the through hole 14. The plurality of first tin plates 18 are evenly distributed around the through holes 14. The plurality of first tin plates 18 and the plurality of via holes 16 are evenly distributed around the through holes 14 in a staggered manner. The second surface 124 of the board body 12 is coated with a tin plating layer 22 in the vicinity of the through hole 14. A solder resist 24 is provided between the through hole 14 and the tin plating layer 22 around the through hole 14.

Mask or Solder Resist), and the tin layer 22 is separated by a solder resist 24 into four sector-shaped regions uniformly distributed around the via holes 14, and the solder paste of the tin-plated layer 22 is prevented from flowing into the via holes 14. Anti-welding paint 24 is generally called "green paint", in order to facilitate the visual inspection of the printed circuit board 10, more green pigments are added to the main paint, and the solder resist 24 is in addition to green. It can also be yellow, white, black or other colors. Solder resist 24 prevents solder paste from flowing through the area where solder resist 24 is located. [0010] It can be understood that the solder mask 24 is disposed around the through hole 14, and the tin plating layer 22 is separated by the solder resist 24 into four regions, so that when the printed circuit board passes through the tin furnace, the solder resist 24 can be The solder paste of the tin plating layer 22 is effectively prevented from flowing into the through holes 14, thereby avoiding the problem of sealing. The tin-plated layer 22 may also be separated by the solder resist 24 into two, three or more regions, and the tin-plated layer 22 may not be separated, but only the solder-proof layer 22 and the through-hole 14 are provided with solder resist. Paint 24. The through hole 14 is not limited to a circular shape, and may be square or other shapes. [0011] Referring to FIG. 3 and FIG. 4 together, the board 12 of the printed circuit board 10 is composed of a plurality of layers. The order of the plate layers 12 from the first surface 122 to the second surface 124 is: a first copper foil layer 20, a first steel plate layer 28, a ground layer 30, a second steel plate layer 32, and a second copper foil layer 26, respectively. . There are also a plurality of 097124123 in the through hole 16 Form No. A0101 Page 5 / 14 pages 1003376132-0 1365017 flops on October 13th, the replacement of the ^ pad (picture is not), the multiple pads are located in the board 12 different The slab is such that the first copper foil layer 2 and the second copper foil layer 26 are electrically connected to the other slabs by the pads in the vias 16. [0012] The plurality of first tin plates 18 are located on the first steel plate layer 28, which penetrates and protrudes from the first copper foil layer 20, and the plurality of first tin plates 18 are electrically connected to the first steel plate layer 28. The ground layer 30 is electrically connected to the ground and is electrically non-conductive with the first steel sheet layer 28 and the second steel sheet layer 32. The second steel plate layer 32 is also provided with a plurality of second tin plates 34 uniformly distributed around the through holes 14, and the plurality of second tin plates 34 penetrate and protrude from the second copper foil layer 26, and the second steel plate layer 32 Keep electrical continuity. The tin-plated layer 22 covers the second copper foil layer 26 and the plurality of second tin pads 34. The solder resist 24 is applied to the second copper foil layer 26 to prevent the solder paste from flowing into the via holes 14 of the tin-plated layer 22. It can be understood that the lamellar structure of the plate body 12 is not limited to the case exemplified in the embodiment, and it is only necessary to establish a conductive path between the layers. Referring to FIG. 5, the working principle of the printed circuit board 1 according to the preferred embodiment of the present invention against electromagnetic interference will be described in detail below. [0014] The printed circuit board 10 is further provided with a screw 36. When assembled, the printed circuit board 10 is fixedly connected to the housing 38 of the electronic device by screws 36. The screw 36 includes a cap portion 362 and a rod portion 364, and the rod portion 364 is A rod portion 364 that is threaded from the end of the cap portion 362 is threaded through the through hole 14 of the printed circuit board 1 and screwed onto the housing 38. The cap portion 362 of the screw 36 is in contact with the plurality of first tin plates 18, and the tin-plated layer 22 of the printed circuit board 1 is in contact with the housing 38. The layers of the printed circuit board 10 remain electrically conductive with the screws 36. In the present embodiment, since the plurality of first tin plates 18 and the tin-plated layer 22 are evenly distributed around the through holes 14, the printed circuit board 1 螺 and the screw 097124123 form number A0101 1003376132-0

1365017 • I

[0015]

[0016] 100 years. On October 13th, the shuttle is replacing the cap portion 362PeUx of the staple 36 and the printed circuit board 1G and the casing 38 have a better contact surface of the hook cloth, which is beneficial to cause noise. The current derivation can be understood as 'the printed circuit board 10 can be connected to any grounding element on the electronic device according to actual needs. The path of the current flowing through the circuit on the printed circuit board 10 to the earth has a plurality of paths such as a strip current flowing through the screw portion 36 of the screw 36, the first tin plate 18, the first plate layer 28, The rod portion 364 of the screw 36, the ground layer 30, and finally the ground, the impedance of the path is low, the current preferentially flows from the path to the ground, and the other path is the current flowing through the cap portion 362 of the screw 36 and the first tin plate. 18, the first steel plate layer 28, the rod portion 364 of the screw 36, the casing 38, and finally to the earthworm. In the present embodiment, the first copper foil layer 2 and the second copper foil layer 26 are passed through the through hole 16 The pads are electrically connected to the other layers, and the layers of the printed circuit board 10 are electrically connected to the screws 36, and the tin-plated layer 22 of the printed circuit board 10 is electrically connected to the housing 38. The flow path is not limited to the two listed above, so that a plurality of current channels are established between the printed circuit board 10 and the ground, so that the current causing noise on the printed circuit board 10 can be effectively directed to the ground and the electromagnetic interference is reduced. In the embodiment, the periphery of the through hole 14 is in the tin layer 2 2 and the through hole 14 There is a solder resist 24 between them, and the through hole 14 is not sealed by means of tape. When the printed circuit board 10 passes through the tin furnace, the solder paste of the tin layer 22 does not flow due to the resistance of the solder resist 24. In the through hole 14, the application of solder resisting around the through hole 14 is simple, and the processing time can be effectively shortened, thereby reducing the production cost. In addition, since the solder resist 24 separates the tin-plated layer 22 into a region in which the four-seven sentence is distributed around the pass-through 14, the printed circuit board 10 and the electronic device's case 097124123 are numbered A0101, page 7 of 14 pages 1003376132-0 1365017 October 13th, 100th, the replacement page [0017] [0020] [0020] [0025] [0025] [0026] After the stomach 38 is fixedly connected, tin plating The contact with the housing 38 provides a good contact surface between the printed circuit board 10 and the housing 38, which facilitates directing the current causing noise on the printed circuit board 10 to the ground, thereby achieving electromagnetic interference resistance. In summary, the present invention complies with the requirements of the invention patent, and patents are filed according to law. However, the above description is only a preferred embodiment of the present invention, and the invention is limited to the domain real type, and those who are familiar with the present technology are equivalently modified in the spirit of the invention. Or variations, are to be included in the scope of the following patent application. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial plan view of a printed circuit board in accordance with a preferred embodiment of the present invention. Figure 2 is a partial bottom plan view of the printed circuit board shown in Figure 1. 3 is a partial cross-sectional view of the printed circuit board shown in FIG. 1 along the line π Ι π 〇 FIG. 4 is a partial cross-sectional view of the printed circuit board shown in FIG. 1 taken along line IV_IV. FIG. 5 is a partial schematic view showing the printed circuit board shown in FIG. 1 fixedly connected to the housing of the electronic device. [Description of main component symbols] Printed circuit board: 10 Board: 12 First surface: 122 Second surface: 124 097124123 Form number Α 0101 Page 8 / Total 14 pages 1003376132-0 1365017 • > 100 years. October 13 Press positive page [0027] Through hole: 14 [0028] Via: 16 [0029] First tin plate: 18 ' [0030] First copper foil layer: 20 ' [0031] Tin plating layer: 22 [0032] Solder resist paint: 24 [0033] • Second copper foil layer: 26 [0034] First steel plate layer: 28 [0035] Ground layer: 30 [0036] Second steel plate layer: 32 [0037] Second tin plate: 34 [0038] Screw: 36 [0039] • Cap: 362 [0040] Rod: 364 [0041] Housing: 38 097124123 Form No. A0101 Page 9 of 14 1003376132-0

Claims (1)

1365017 October 13, 100 revised replacement page VII. Patent application scope: 1. A printed circuit board comprising a plate body having a through hole in the plate body The printed circuit board is fixedly connected to the grounding component by the through hole, and a surface of the printed circuit board is provided with a tin plating layer around the through hole, the tin plating layer is in contact with the grounding component, and the printed circuit board and the printed circuit board are The grounding element is electrically conductive, and the improvement is that the plate body comprises a first copper foil layer, a first steel plate layer, a grounding layer, a second steel plate layer and a second copper foil layer, and the first steel plate a plurality of first tin discs are disposed on the layer, the plurality of first tin discs penetrating and protruding from the first copper foil layer, and the second steel sheet layer is provided with a plurality of second tin discs, and the plurality of second tin discs are penetrated and Protruding the second copper foil layer, the tin plating layer covers the second copper foil layer and the plurality of second tin disks, and the through hole is provided around the through hole for preventing the solder paste of the tin plating layer from flowing into the through hole Anti-weld paint. 2. The printed circuit board of claim 1, wherein the tin plating layer is separated by the solder resist paint into four sector regions uniformly distributed around the through hole. 3. The printed circuit board of claim 1, wherein the printed circuit The board is also provided with a screw that passes through the through hole of the printed circuit board and is screwed to the grounding member. 4. The printed circuit board of claim 3, wherein the grounding element is a housing of an electronic device. 5. The printed circuit board of claim 3, wherein the cap portion of the screw is in contact with the plurality of tin pads and is electrically connected to the ground layer. 6. The printed circuit board of claim 1, wherein the solder resist is applied to the second copper foil layer. 7. The printed circuit board of claim 1, wherein the printed circuit board is further provided with a plurality of vias, the first copper foil layer and the second copper foil layer 097124123, Form No. A0101, page 10 / Page 14 of 1003376132-0 1365017 * . On October 13, 100, the replacement page was electrically connected to the other layers by the pads inside the tie. The printed circuit board of claim 1, wherein the solder resist is green paint 0 097124123 Form No. A0101 Page 11 of 14 1003376132-0