Printing steel mesh for miniature pentagonal filter and printing method

Abstract

The invention provides a printing steel mesh for a miniature pentagonal filter and a printing method. The printing steel mesh for the miniature pentagonal filter comprises five printing trepanning areas, the five printing trepanning areas are configured to print solder paste to five bonding pads in a one-to-one correspondence mode, and the five bonding pads and five pins of the miniature pentagonal filter are arranged in a one-to-one correspondence mode. Each printing hole area comprises a bonding pad part and an extension part which is located on one side of the bonding pad part and connected with the bonding pad part, the projection of the bonding pad part of each printing hole area on the corresponding bonding pad coincides with the corresponding bonding pad, and the extension part of each printing hole area is located on the side, away from the bonding pad part of any adjacent printing hole area, of the corresponding bonding pad part. And the extension part of each printing hole area is positioned on one side, far away from the pad part of the printing hole area farthest from the other straight line, of the corresponding pad part. According to the printing steel mesh for the miniature pentagonal filter, accurate positioning of the pentagonal filter can be promoted on the basis of reducing pseudo soldering, and bridging is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic surface mounting, in particular to a printed steel mesh for micro five-corner filter and a printing method. BACKGROUND

[0002] For the surface mounting of the filter, it needs to rely on the steel mesh to print the solder paste and then realize welding on the pad. The pins of the filter are prone to false welding. For example, the utility model patent application with the application number CN202021735446.6 sets a hollow part and an outward expansion part on at least one side of the hollow part on the steel mesh. The hollow part realizes the printing of the solder paste area with the size of the filter pin, and the outward expansion part realizes the printing of the solder paste area with the size of the outer periphery of the filter pin. In this way, the solder paste area finally printed on the pad is larger than the size of the filter pin, so that there is enough solder tin to climb the connector during welding, so that there is enough solder tin to climb more than half the height of the pin, thereby solving the problem of false welding of the pin. However, for the five-corner filter, it includes five pins, and the five pins are distributed in the five corners, also known as five-pin filter. Especially for the micro five-corner filter, its size is small, even 1.4*1.1*0.6, and the distance between the five pins is small. If the steel mesh sets the outward expansion part on the side close to the adjacent hollow part, it is easy to cause the bridging problem. SUMMARY

[0003] The purpose of the present application is to overcome the shortcomings in the prior art and provide a printed steel mesh for micro five-corner filter and a printing method which can reduce false welding, promote precise positioning of the five-corner filter, and reduce bridging.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] A printed steel mesh for micro five-corner filter, comprising five printing aperture areas, the five printing aperture areas are configured to print solder paste to five pads one by one, the five pads are arranged one by one with the five pins of the micro five-corner filter, each printing aperture area comprises a pad part and an expansion part located on one side of the pad part and connected with the pad part, the projection of the pad part of each printing aperture area on the corresponding pad coincides with the corresponding pad, the expansion part of each printing aperture area is located on the side of the pad part of the corresponding pad part away from any adjacent printing aperture area, and the expansion part of each printing aperture area is located on the side of the pad part of the corresponding pad part farthest away from another straight line.

[0006] In one embodiment, the thickness of the side of the extension of each printed aperture region away from the corresponding pad portion is at least partially greater than the thickness of the corresponding pad portion, so that the thickness of the solder paste printed on the side of the corresponding pad is at least partially greater than the thickness of the solder paste printed on the corresponding pad.

[0007] In one embodiment, in each of the printed aperture areas, the thickness of the corresponding extension gradually increases in the direction from the side of the extension closest to the corresponding pad to the side furthest from the corresponding pad, so that the thickness of the solder paste printed on the side of the corresponding pad gradually increases.

[0008] In one embodiment, the thickness of the side of the extension portion of each printed opening area near the corresponding pad portion is the same as the thickness of the side of the corresponding pad portion near the corresponding extension portion;

[0009] The thickness of the side of the pad portion of each printed opening area that is close to the corresponding extension portion is 3 / 5 to 2 / 3 of the thickness of the side of the corresponding extension portion that is away from the corresponding pad portion.

[0010] In one embodiment, the thickness of the edge of the pad portion of each of the printed opening areas is 0.08 mm to 0.10 mm.

[0011] In one embodiment, the thickness of the pad portion of each printed aperture area gradually increases in the direction from the geometric center point of the pad portion toward the edge.

[0012] In one embodiment, the length of the extension of each printed opening area is the same as the length of the side where the corresponding pad portion is located;

[0013] The width of the extension of each printed aperture area decreases as the distance between the corresponding pad portion and the pad portion of the printed aperture area with the longest straight-line distance increases.

[0014] In one embodiment, the width of the extension portion of each printed opening area is 0.06±0.005mm when the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.25mm to 0.35mm.

[0015] In one embodiment, the width of the extension portion of each printed opening area is 0.05 ± 0.005 mm when the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.36 mm to 0.75 mm.

[0016] In one embodiment, the width of the extension portion of each printed opening area is 0.04 ± 0.005 mm when the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.8 mm to 1.0 mm.

[0017] In one embodiment, the five printed opening areas are the same size;

[0018] The pad portions of the four printed aperture areas are arranged in a rectangular array, and the straight-line distance between the pad portions of each pair of adjacent printed aperture areas is the same.

[0019] The axis of symmetry of the pad portion of another printed aperture area coincides with the axis of symmetry of the pad portion of any two other adjacent printed aperture areas.

[0020] In one embodiment, the distance between the pad portion of each of the printed opening areas and the pad portion of each adjacent printed opening area is 0.25 mm;

[0021] The length and width of the pad portion in each of the printed opening areas are 0.325 mm.

[0022] In one embodiment, the distance between the pad portion of each of the printed opening areas and the pad portion of each adjacent printed opening area is 0.258 mm;

[0023] The length and width of the pad portion in each of the printed opening areas are 0.33 mm.

[0024] A printing method includes the following steps:

[0025] Solder paste is extruded onto the printed stencil for the miniature pentagonal filter as described in any of the above embodiments, so that the solder paste avoids the extension portion and the pad portion of each of the printed opening areas;

[0026] The solder paste is printed and scraped so that it passes over the extension portion and the pad portion of each printed opening area, and falls onto the corresponding pad and one side of the corresponding pad.

[0027] Compared with the prior art, the present invention has at least the following advantages:

[0028] The printed stencil for the miniature pentagonal filter of the present invention has an extension portion located on one side of the pad portion and connected to the pad portion. The projection of the pad portion of each printed aperture area onto the corresponding pad coincides with the corresponding pad, i.e., solder paste is printed over the entire pad area through the pad portion. Then, the extension portion of each printed aperture area is located on the side of the corresponding pad portion away from any adjacent printed aperture area, which increases the amount of solder paste printed at the pad. This causes the solder paste in the extension portion to retract during reflow soldering, thereby strengthening the soldering of the miniature pentagonal filter. This effectively reduces cold solder joints and avoids the area between two adjacent pads from becoming an extension area, thus initially reducing the risk of bridging. In addition, the extension portion of each printed aperture area is located on the corresponding pad portion away from the pad of the printed aperture area with the furthest straight-line distance. On one side of the pentagon, the pad at the top of the pentagon has an extension on the side of the corresponding pad that is away from the other four pads. The two pads in the middle of the pentagon have extensions on the sides of the two pads that are away from each other. The two pads at the bottom of the pentagon have extensions on the sides of the pads that are away from the top of the pentagon. This causes the solder paste printed on the extensions of the pentagon to melt and retract during reflow soldering, generating unbalanced surface tension to produce lateral tension. By controlling the pentagon filter to be precisely aligned, the lateral tensions cancel each other out. In the case of misalignment of the pentagon filter, the uneven lateral tensions drive the pentagon filter to be precisely positioned, further reducing the risk of bridging. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a printed steel mesh for a miniature pentagonal filter according to an embodiment of the present invention;

[0031] Figure 2 for Figure 1 Another schematic diagram of the printed stencil used for the miniature pentagonal filter is shown.

[0032] Figure 3 for Figure 1 The cross-sectional view shown is of a printed steel mesh used for a miniature pentagonal filter.

[0033] Figure 4 This is a schematic diagram of the structure of a printed steel mesh for a miniature pentagonal filter according to another embodiment of the present invention. Detailed Implementation

[0034] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] This application provides a printed stencil for a miniature pentagonal filter. The aforementioned printed stencil for a miniature pentagonal filter includes five printed opening areas, each configured to correspond one-to-one with solder paste printed onto five pads. The five pads correspond one-to-one with the five pins of the miniature pentagonal filter. Each printed opening area includes a pad portion and an extension portion located on one side of the pad portion and connected to it. The projection of the pad portion of each printed opening area onto the corresponding pad coincides with the corresponding pad. The extension portion of each printed opening area is located on the side of the corresponding pad portion furthest from the pad portion of any adjacent printed opening area, and also on the side of the corresponding pad portion furthest from the pad portion of the other printed opening area with the longest linear distance.

[0038] The aforementioned miniature pentagonal filter uses a printed stencil with an extension portion located on one side of the pad portion and connected to it. The projection of the pad portion of each printed aperture area onto the corresponding pad coincides with the corresponding pad, meaning solder paste is printed over the entire pad area through the pad portion. The extension portion of each printed aperture area is located on the side of the corresponding pad portion away from any adjacent printed aperture area. This increases the amount of solder paste printed at the pad, causing the solder paste in the extension portion to retract during reflow soldering, thus strengthening the soldering of the miniature pentagonal filter. This effectively reduces cold solder joints and avoids the area between two adjacent pads becoming an extension area, initially mitigating the risk of bridging. Furthermore, the extension portion of each printed aperture area is located on the corresponding pad portion away from the pad of the printed aperture area furthest in a straight line. On one side of the pentagon, the pad at the top of the pentagon has an extension on the side of the corresponding pad that is away from the other four pads. The two pads in the middle of the pentagon have extensions on the sides of the two pads that are away from each other. The two pads at the bottom of the pentagon have extensions on the sides of the pads that are away from the top of the pentagon. This causes the solder paste printed on the extensions of the pentagon to melt and retract during reflow soldering, generating unbalanced surface tension to produce lateral tension. By controlling the pentagon filter to be precisely aligned, the lateral tensions cancel each other out. In the case of misalignment of the pentagon filter, the uneven lateral tensions drive the pentagon filter to be precisely positioned, further reducing the risk of bridging.

[0039] It is understandable that in reflow soldering, the small size and close proximity of the pads of the tiny pentagonal filter make precise alignment of the five-pin filter pins onto the pads during soldering. If misalignment occurs during placement, even if bridging has not yet occurred, it is easily exacerbated during further reflow soldering due to uneven surface tension of the solder paste, leading to bridging. In this application, the extension portion of the pad at the top of the pentagon is located on the side of the pad portion away from the other four pad portions, while the extension portions of the two pads in the middle of the pentagon are respectively located on... The two corresponding pads on opposite sides of the pentagon, and the two pads at the bottom of the pentagon, have their corresponding extended portions located on the side of the pad corresponding to the pad at the top of the pentagon. This causes the solder paste corresponding to the extended portions of the pentagonal distribution to melt and retract during reflow soldering, generating unbalanced surface tension and lateral tension. By controlling the lateral tensions to cancel each other out when the pentagonal filter is precisely aligned, the uneven lateral tension further promotes the precise positioning of the pentagonal filter even if it is not precisely aligned, thus mitigating bridging risk. To better understand the printed stencil for the miniature pentagonal filter of this application, the following further explanation is provided:

[0040] Please refer to the following: Figures 1 to 3 One embodiment of the printed stencil for a miniature pentagonal filter includes five printed opening areas 100. The five printed opening areas 100 are configured to print solder paste onto five pads in a one-to-one correspondence. The five pads are configured to correspond one-to-one with the five pins of the miniature pentagonal filter. Each printed opening area 100 includes a pad portion 110 and an extension portion 120 located on one side of the pad portion 110 and connected to the pad portion 110. The projection of the pad portion 110 of each printed opening area 100 onto the corresponding pad coincides with the corresponding pad. The extension portion 120 of each printed opening area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of any adjacent printed opening area 100, and the extension portion 120 of each printed opening area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of the other printed opening area 100 with the furthest straight-line distance.

[0041] The aforementioned miniature pentagonal filter uses a printed stencil 10 such that the extension portion 120 is located on one side of the pad portion 110 and connected to the pad portion 110. The projection of the pad portion 110 of each printed aperture area 100 onto the corresponding pad coincides with the corresponding pad, that is, solder paste is printed over the entire pad area through the pad portion 110. Then, the extension portion 120 of each printed aperture area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of any adjacent printed aperture area 100, such that... The extension portion 120 increases the amount of solder paste printed at the pads, thereby causing the solder paste in the extension portion 120 to retract during reflow soldering, which strengthens the soldering of the miniature pentagonal filter. This effectively reduces cold solder joints and avoids the area between two adjacent pads becoming an extension area, thus initially mitigating the risk of bridging. Furthermore, the extension portion 120 of each printed aperture area 100 is located on the side of the corresponding pad portion 110 furthest from the pad portion 110 of the other printed aperture area 100. Please refer to [further details omitted]. Figures 1 to 2 The extension 120 of the pad at the top of the pentagon is located on the side of the corresponding pad 110a away from the other four pads 110. The extension 120 of the two pads in the middle of the pentagon is located on the side of the corresponding pads 110b and 110c away from each other. The extension 120 of the two pads at the bottom of the pentagon is located on the side of the corresponding pads 110d and 110e away from the pads 110a of the top of the pentagon. During reflow soldering, the extension 120 of the pentagon-distributed solder portions melts and retracts the solder paste formed by the printed solder paste, generating unbalanced surface tension and lateral tension. By controlling the pentagon filter to be precisely aligned, the lateral tensions cancel each other out. In the case of the pentagon filter not being precisely aligned, the unbalanced lateral tension promotes the precise positioning of the pentagon filter, further reducing the risk of bridging.

[0042] Please refer to the following: Figures 1 to 3 In one embodiment, the thickness of the side of the extension 120 of each printed aperture area 100 away from the corresponding pad 110 is at least partially greater than the thickness of the corresponding pad 110, so that the thickness of the solder paste printed on the side of the corresponding pad is at least partially greater than the thickness of the solder paste printed on the corresponding pad. It is understood that during reflow soldering, the solder paste printed on the extension 120 corresponding to the pentagonally distributed solder portions melts and retracts, generating a large lateral tensile force. This achieves better solder strength for the miniature pentagonal filter, thereby reducing cold solder joints. Furthermore, even when the pentagonal filter is not precisely aligned, the significant unevenness of the lateral tensile force promotes precise positioning of the pentagonal filter, further ensuring the reduction of bridging.

[0043] Please refer to the following: Figures 1 to 3In one embodiment, the thickness of the extension 120 of each printed opening area 100 gradually increases in the direction from the side of the corresponding pad portion 110 to the side away from the corresponding pad portion 110, so that the thickness of the solder paste printed on the side of the corresponding pad gradually increases. Furthermore, in the direction from the side of the extension 120 of each printed aperture area 100 near the corresponding pad portion 110 to the side away from the corresponding pad portion 110, the thickness of the corresponding extension 120 is uniformly increased, so that the thickness of the solder paste printed on the side of the corresponding pad is increased more uniformly, so that the extension 120 of each printed aperture area 100 is connected to the side of the corresponding pad portion 110, and one end face of the extension 120 of each printed aperture area 100 is on the same plane as one end face of the corresponding pad portion 110, while the other end face of the extension 120 of each printed aperture area 100 is a wedge-shaped surface, which is set towards the corresponding pad portion 110 and is connected to the other end face of the corresponding pad portion 110, which is beneficial for controlling the lateral tension generated by the melting and shrinkage of the solder paste during reflow soldering.

[0044] Please refer to the following: Figures 1 to 3 In one embodiment, the thickness of the side of the extension 120 of each printed aperture area 100 near the corresponding pad 110 is the same as the thickness of the side of the corresponding pad 110 near the corresponding extension 120. Furthermore, the thickness of the side of the pad 110 of each printed aperture area 100 near the corresponding extension 120 is 3 / 5 to 2 / 3 of the thickness of the side of the extension 120 away from the corresponding pad 110. This not only improves the soldering strength of the miniature pentagonal filter and reduces cold solder joints, but also effectively ensures control of the lateral pull force generated by the melting and retraction of solder paste during reflow soldering. It is understandable that when the pins of the pentagonal filter are not precisely aligned with the corresponding pads, in order to increase the significance of the unevenness of the lateral tension and promote the precise positioning of the pentagonal filter, simply increasing the thickness of the solder paste printed on the extension portion 120 will result in excessive solder paste printed on the extension portion 120, which will aggravate the fluidity of the solder paste after melting and cause bridging, as well as problems such as excessively large solder dots and solder balls, resulting in short circuit risks. Therefore, in this application, the thickness of the side of the pad portion 110 of each printed opening area 100 near the corresponding extension portion 120 is controlled to be 3 / 5 to 2 / 3 of the side of the corresponding extension portion 120 away from the corresponding pad portion 110. This controls the thickness of the solder paste printed on the extension portion 120, better ensures the precise positioning of the pentagonal filter, and reduces the risk of short circuits.

[0045] In one embodiment, the thickness of the edge of the pad portion of each printed aperture area is 0.08 mm to 0.10 mm. Further, the thickness of the pad portion of each printed aperture area gradually increases in the direction from the geometric center point of the pad portion towards the edge. Further, the thickness of the pad portion of each printed aperture area increases uniformly in the direction from the geometric center point of the pad portion towards the edge. Further, the thickness at the geometric center point of the pad portion of each printed aperture area is 4 / 5 to 9 / 10 of the thickness of the edge of the corresponding pad portion, such that one end face of the extension portion of each printed aperture area is on the same plane as one end face of the corresponding pad portion, and the other end face of the pad portion of each printed aperture area is a concave conical surface, the peripheral portion of which is connected to the other end face of the corresponding extension portion. It is understandable that even if the thickness at the geometric center of the pad is less than the thickness at the periphery, the solder paste printed on the pad will also have a greater thickness at the geometric center and a smaller thickness at the edge. This will cause the surface tension of the solder paste printed on the pad to drive the solder to shrink towards the center when it melts, thereby further reducing the risk of bridging.

[0046] In one embodiment, the openings of the pad portion and extension portion of each printed via area satisfy the following: area ratio ≥ 0.66, width-to-depth ratio ≥ 1.66. Further, the openings of the pad portion and extension portion of each printed via area satisfy the following: 0.8 ≥ area ratio ≥ 0.66, 2 ≥ width-to-depth ratio ≥ 1.66. Further, the area ratio and width-to-depth ratio of the openings of the pad portion and extension portion of each printed via area are the same. It can be understood that the area ratio is the area of ​​the opening / the wall area of ​​the opening; while the width-to-depth ratio is the width of the opening / the thickness at the location of the opening. Further, the gap distance between the edges of two adjacent vias is ≥ 0.2 mm. Further, the gap distance between the edges of two adjacent vias is ≤ 0.3 mm. Further, the gap distance between the edges of two adjacent vias is 0.25 mm, which better ensures the printing effect of solder paste.

[0047] Please see Figure 4 In one embodiment, one side of the pad portion 110 of each printed via area 100 is connected to the corresponding extension portion 120. Further, among the remaining three side edges of the pad portion 110 of each printed via area 100, a chamfer structure is provided at the intersection of each adjacent two side edges. Further, the chamfer structure is a C-shaped chamfer structure or an R-shaped chamfer structure. Further, in each chamfer structure of the pad portion 110 of each printed via area 100, the lengths of the two cutting edges are 1 / 4 to 1 / 3 of the length of the corresponding side, reducing solder paste residue and mitigating the risk of bridging.

[0048] Please refer to the following: Figures 1 to 3In one embodiment, the length of the extension 120 of each printed aperture area 100 is the same as the length of the side where the corresponding pad portion 110 is located. Further, the width of the extension 120 of each printed aperture area 100 decreases as the distance between the corresponding pad portion 110 and the pad portion 110 of the other printed aperture area 100 with the furthest straight-line distance increases. It is understandable that the greater the distance between the pads, the more difficult it is to cancel out the lateral tension generated by the surface tension of the solder paste after melting at the corresponding pads. In order to better achieve mutual cancellation of the lateral tension generated by the surface tension of the solder paste formed by the extension portion 120 of the printed aperture area 100 and the pad portion 110 after melting, the width of the extension portion 120 of each printed aperture area 100 is reduced as the distance between the corresponding pad portion 110 and the pad portion 110 of the printed aperture area 100 with the longest straight-line distance increases. This is beneficial to improve the effective control of mutual cancellation of the lateral tension generated by the surface tension of the solder paste formed by the extension portion 120 of the printed aperture area 100 and the pad portion 110 after melting, that is, it is beneficial to achieve effective control of the cancellation of each lateral tension when the pentaangular filter is in precise alignment.

[0049] Please refer to the following: Figures 1 to 3 In one embodiment, the five printed aperture regions 100 are of the same size. Further, the pad portions 110 of four printed aperture regions 100 are arranged in a rectangular array, and the straight-line distance between any two adjacent pad portions 110 of the corresponding printed aperture regions 100 is the same. Further, the axis of symmetry of the pad portion 110 of another printed aperture region 100 coincides with the axis of symmetry of the pad portions 110 of any other two adjacent printed aperture regions 100.

[0050] In one embodiment, the distance between the pad portion of each printed aperture area and the pad portion of each adjacent printed aperture area is 0.25 mm. Further, the length and width of the pad portion of each printed aperture area are both 0.325 mm.

[0051] In one embodiment, the distance between the pad portion of each printed aperture area and the pad portion of each adjacent printed aperture area is 0.258 mm. Further, the length and width of the pad portion of each printed aperture area are both 0.33 mm.

[0052] In one embodiment, the width of the extended portion of each printed aperture area is 0.06±0.005mm when the distance between the corresponding pad portion and the pad portion of the printed aperture area with the longest straight-line distance is 0.25mm to 0.35mm. This effectively ensures the stable cancellation of each lateral tension when the pentagonal filter is in precise alignment.

[0053] In one embodiment, the width of the extension portion of each printed aperture area is 0.05±0.005mm when the distance between the corresponding pad portion and the pad portion of the printed aperture area with the longest straight-line distance is 0.36mm to 0.75mm, which better ensures the stable cancellation of each lateral tension when the pentagonal filter is in precise alignment.

[0054] In one embodiment, the width of the extension portion of each printed aperture area is 0.04±0.005mm when the distance between the corresponding pad portion and the pad portion of the printed aperture area with the longest straight-line distance is 0.8mm to 1.0mm, which better ensures the stable cancellation of each lateral tension when the pentagonal filter is in precise alignment.

[0055] It is understandable that a larger width of the extension section increases the amount of solder paste printed, exacerbates the flow of the molten solder paste causing bridging, and results in excessively large solder dots. On the other hand, it causes some solder paste to be farther away from the pads. During reflow soldering, the large difference in surface tension makes it easier to form independent solder balls, increasing the risk of short circuits. Therefore, in this application, the width of the extension section is controlled as described above to ensure the accurate positioning of the pentagonal filter while mitigating the risk of short circuits.

[0056] It should be noted that, based on conventional technical methods, uneven surface tension during reflow soldering can easily lead to tombstoning, which manifests as the pentaangular filter partially or completely standing up, affecting the quality and reliability of the pentaangular filter soldering. In this application, although the uneven surface tension after the solder paste melts is utilized, the thickness, width, and position of the pads and extensions in the five printed aperture areas are set to not only reduce the tombstoning phenomenon but also effectively achieve the precise positioning of the pentaangular filter, thereby ensuring the quality and reliability of the pentaangular filter soldering.

[0057] This application also provides a printing method. To better understand the printing method of this application, the following further explanation is provided:

[0058] One embodiment of the printing method includes the following steps:

[0059] S100. Extrude solder paste onto the printed stencil for the miniature pentagonal filter in any of the above embodiments, ensuring that the solder paste avoids the extension portion and pad portion of each printed opening area. Further, please refer to... Figures 1 to 3The printed stencil 10 for the miniature pentagonal filter includes five printed opening areas 100. The five printed opening areas 100 are configured to print solder paste onto five pads in a one-to-one correspondence. The five pads correspond one-to-one with the five pins of the miniature pentagonal filter. Each printed opening area 100 includes a pad portion 110 and an extension portion 120 located on one side of the pad portion 110 and connected to the pad portion 110. The projection of the pad portion 110 of each printed opening area 100 onto the corresponding pad coincides with the corresponding pad. The extension portion 120 of each printed opening area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of any adjacent printed opening area 100, and the extension portion 120 of each printed opening area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of the other printed opening area 100 with the furthest straight-line distance.

[0060] S200: Perform a solder paste printing and squeegeeing operation, so that the solder paste is squeegeed over the extension portion and pad portion of each printed opening area, and falls onto the corresponding pad and one side of the corresponding pad. It is understood that the solder paste squeegeeing parameters are the same for the solder paste printing of the extension portion and pad portion of each printed opening area, and it is a routine solder paste printing squeegeeing operation; therefore, detailed steps and parameters will not be described in detail here.

[0061] The printing method described above effectively reduces the risks of bridging and poor soldering, and also significantly improves the precision positioning and soldering of the pentaangular filter.

[0062] Compared with the prior art, the present invention has at least the following advantages:

[0063] The printed stencil 10 for the miniature pentagonal filter of the present invention has an extension portion 120 located on one side of the pad portion 110 and connected to the pad portion 110. The projection of the pad portion 110 of each printed aperture area 100 onto the corresponding pad coincides with the corresponding pad, that is, solder paste is printed over the entire pad area through the pad portion 110. Then, the extension portion 120 of each printed aperture area 100 is located on the side of the corresponding pad portion 110 away from the pad portion 110 of any adjacent printed aperture area 100, such that... The extension portion 120 increases the amount of solder paste printed at the pads, thereby causing the solder paste in the extension portion 120 to retract during reflow soldering, which strengthens the soldering of the miniature pentagonal filter. This effectively reduces cold solder joints and avoids the area between two adjacent pads becoming an extension area, thus initially mitigating the risk of bridging. Furthermore, the extension portion 120 of each printed aperture area 100 is located on the side of the corresponding pad portion 110 furthest from the pad portion 110 of the other printed aperture area 100. Please refer to [further details omitted]. Figures 1 to 2The extension 120 of the pad at the top of the pentagon is located on the side of the corresponding pad 110a away from the other four pads 110. The extension 120 of the two pads in the middle of the pentagon is located on the side of the corresponding pads 110b and 110c away from each other. The extension 120 of the two pads at the bottom of the pentagon is located on the side of the corresponding pads 110d and 110e away from the pads 110a of the top of the pentagon. During reflow soldering, the extension 120 of the pentagon-distributed solder portions melts and retracts the solder paste formed by the printed solder paste, generating unbalanced surface tension to produce lateral tension. By controlling the pentagon filter to be precisely aligned, the lateral tensions cancel each other out. In the case of the pentagon filter not being precisely aligned, the unbalanced lateral tension promotes the precise positioning of the pentagon filter, further reducing the risk of bridging.

[0064] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A printed stencil for a miniature pentagonal filter, comprising five printed opening areas, wherein the five printed opening areas are configured to correspond one-to-one with five pads for printing solder paste onto five pads, and the five pads are configured one-to-one with five pins of the miniature pentagonal filter, characterized in that, Each of the printed via areas includes a pad portion and an extension portion located on one side of the pad portion and connected to the pad portion. The projection of the pad portion of each of the printed via areas onto the corresponding pad coincides with the corresponding pad. The extension portion of each of the printed via areas is located on the side of the corresponding pad portion away from the pad portion of any adjacent printed via area, and the extension portion of each of the printed via areas is located on the side of the corresponding pad portion away from the pad portion of the other printed via area with the furthest straight-line distance.

2. The printed stencil for a miniature pentagonal filter according to claim 1, characterized in that, The thickness of the side of the extension portion of each printed opening area away from the corresponding pad portion is at least partially greater than the thickness of the corresponding pad portion, so that the thickness of the solder paste printed on the side of the corresponding pad is at least partially greater than the thickness of the solder paste printed on the corresponding pad.

3. The printed stencil for a miniature pentagonal filter according to claim 2, characterized in that, In each of the printed opening areas, the thickness of the extended portion gradually increases in the direction from the side near the corresponding pad portion to the side away from the corresponding pad portion, so that the thickness of the solder paste printed on the side of the corresponding pad gradually increases.

4. The printed stencil for a miniature pentagonal filter according to claim 2, characterized in that, The thickness of the side of the extended portion of each printed opening area near the corresponding pad portion is the same as the thickness of the side of the corresponding pad portion near the corresponding extended portion. The thickness of the side of the pad portion of each printed opening area that is close to the corresponding extension portion is 3 / 5 to 2 / 3 of the thickness of the side of the corresponding extension portion that is away from the corresponding pad portion.

5. The printed stencil for a miniature pentagonal filter according to claim 1, characterized in that, The thickness of the edge of the pad portion in each of the printed opening areas is 0.08 mm to 0.10 mm; and / or, The thickness of the pad portion in each printed aperture area gradually increases in the direction from the geometric center point of the pad portion toward the edge.

6. The printed stencil for a miniature pentagonal filter according to claim 1, characterized in that, The length of the extension portion of each printed opening area is the same as the length of the side where the corresponding pad portion is located; The width of the extension of each printed aperture area decreases as the distance between the corresponding pad portion and the pad portion of the printed aperture area with the longest straight-line distance increases.

7. The printed stencil for a miniature pentagonal filter according to claim 1, characterized in that, When the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.25mm to 0.35mm, the width of the extended portion is 0.06±0.005mm; and / or, When the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.36mm to 0.75mm, the width of the extended portion is 0.05±0.005mm; and / or, When the distance between the corresponding pad portion and the pad portion of the printed opening area furthest in a straight line is 0.8 mm to 1.0 mm, the width of the extended portion of each of the printed opening areas is 0.04 ± 0.005 mm.

8. The printed stencil for a miniature pentagonal filter according to claim 1, characterized in that, The five printed opening areas are the same size; The pad portions of the four printed aperture areas are arranged in a rectangular array, and the straight-line distance between the pad portions of each pair of adjacent printed aperture areas is the same. The axis of symmetry of the pad portion of another printed aperture area coincides with the axis of symmetry of the pad portion of any two other adjacent printed aperture areas.

9. The printed stencil for a miniature pentagonal filter according to any one of claims 1 to 8, characterized in that, The distance between the pad portion of each of the printed opening areas and the pad portion of each adjacent printed opening area is 0.25 mm; The length and width of the pad portion in each of the printed opening areas are 0.325 mm; or, The distance between the pad portion of each of the printed opening areas and the pad portion of each adjacent printed opening area is 0.258 mm; The length and width of the pad portion in each of the printed opening areas are 0.33 mm.

10. A printing method, characterized in that, Includes the following steps: Solder paste is extruded onto the printed stencil for the miniature pentagonal filter according to any one of claims 1 to 9, such that the solder paste avoids the extension portion and the pad portion of each of the printed opening areas; The solder paste is printed and scraped so that it passes over the extension portion and the pad portion of each printed opening area, and falls onto the corresponding pad and one side of the corresponding pad.

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