FPC (Flexible Printed Circuit) pseudo soldering prevention structure
By using elliptical through holes and through hole slot structures on the FPC, the dummy soldering problems caused by unfilling solder paste and gas retention are solved, improving welding quality and reducing production costs.
Patent Information
- Application Number
- CN202421691237.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-17
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2034-07-17
AI Technical Summary
In the existing FPC production, it is difficult to detect the appearance detection due to the incomplete filling of solder paste or the presence of gas, resulting in increased production costs and waste of materials.
Elliptical through holes and through hole slots are used to replace conventional hole slots, expand the contact area of solder paste and facilitate gas discharge, ensuring stable connection.
Improve welding quality, reduce dummy welding problems, and reduce production costs.
Smart Images
Figure CN223093959U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of FPC, in particular to an anti-false soldering structure on an FPC. Background Art
[0002] An FPC is usually a double-sided board structure. On the upper and lower stacked single-sided boards, hole slots are reserved at the positions of their respective pads. During production, solder paste is brushed and filled in the hole slots to conduct the pads of the two single-sided boards, thereby realizing the connection of the internal circuits.
[0003] During production, due to some human or non-human reasons, there will be false soldering phenomena such as incomplete filling of solder paste and gas in the solder paste during the solder paste brushing operation, resulting in the pads of the two single-sided boards not being in full contact or having a shallow external contact but an internal void. These abnormalities are difficult to detect in the appearance inspection process and generally only appear in the final functional test or destructive test. Only after that can selection, rework operations be carried out or even only scrapped, wasting manpower, material resources and raw materials and increasing the production cost. Summary of the Utility Model
[0004] In view of the problems existing in the above-mentioned prior art, the utility model provides an anti-false soldering structure on an FPC, which replaces the conventional round holes or square holes with oval through holes and via slots, can expand the area for accommodating solder paste without affecting the circuits on the substrate, thereby increasing the contact area between the solder paste and the pads on the second substrate, and facilitating the smooth flow of the solder paste and the complete discharge of gas, avoiding the internal false soldering problem caused by gas remaining in the solder paste, and improving the welding quality.
[0005] To solve the above technical problems, a technical solution adopted by the utility model is as follows:
[0006] An anti-false soldering structure on an FPC, wherein two single-sided boards are overlapped on the FPC, and on each of the single-sided boards, connected circuits and a plurality of pads are printed or etched. The solder paste can pass through the upper single-sided board and contact and connect with the lower single-sided board to conduct the pads on the two single-sided boards in pairs;
[0007] The FPC includes a first protective film, a first substrate, a second protective film, a third protective film and a second substrate from top to bottom. A plurality of the pads are provided on the first substrate and the second substrate. A through hole is provided on each of the pads on the first substrate, and a via slot is provided above or below each of the through holes on the first protective film, the second protective film and the third protective film;
[0008] Each of the through holes and the via slots is oval, and the contour projection thereof falls inside the contour edge of a pad on the second substrate.
[0009] As a further elaboration of the above technical solution:
[0010] In the above technical solution, the contour edges of each of the via holes all fall outside the contour edge of one of the through holes.
[0011] In the above technical solution, the central axes of the pads that are pairwise matched on the first substrate and the second substrate coincide with each other, and both coincide with the central axes of several of the via holes at both ends thereof.
[0012] In the above technical solution, the area of each of the via holes on the first protective film and the second protective film is 1.8 to 2.5 times the area of the through hole communicated therewith.
[0013] In the above technical solution, the area of each of the pads on the second substrate is 1.5 to 2.0 times the area of the via hole communicated therewith.
[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows: By replacing the conventional round holes or square holes with oval through holes and via holes, the area of the region for accommodating solder paste can be enlarged without affecting the circuits on the substrate, thereby increasing the contact area between the solder paste and the pads on the second substrate, ensuring a stable contact connection therebetween, and moreover, the through holes and the via holes have no sharp corners and the smooth surfaces facilitate the smooth flow of the solder paste and completely discharge the gas, avoiding the problem of internal soldering defects caused by gas remaining in the solder paste, improving the soldering quality, and the different moving directions and angles of the solder paste brushing blade have little influence on the solder paste brushing effect and the soldering effect, and it is applicable to most solder paste brushing devices. Description of the Drawings
[0015] Figure 1 is a schematic structural view of the present utility model;
[0016] Figure 2 is a schematic structural view of the pads, the through holes and the via holes in the present utility model.
[0017] In the figure: 1, the first protective film; 2, the first substrate; 3, the second protective film; 4, the third protective film; 5, the second substrate; 6, the pad; 7, the through hole; 8, the via hole. Detailed Description of the Embodiment
[0018] The present utility model will be further described in detail below with reference to the drawings.
[0019] The embodiments described with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a number of" and "a plurality of" is two or more, unless otherwise specifically defined. In the present application, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances. In the present application, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above and over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below and under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.
[0020] As Figure 1-2 shown, there is an anti-false soldering structure on the FPC. Two single-sided boards are overlapped on the FPC. On each single-sided board, connected circuits and a number of pads are printed or etched. Solder paste can pass through the upper single-sided board and contact and connect with the lower single-sided board to conduct the pads on the two single-sided boards in pairs;
[0021] From top to bottom, the FPC includes a first protective film 1, a first substrate 2, a second protective film 3, a third protective film 4, and a second substrate 5. A plurality of pads 6 are provided on the first substrate 2 and the second substrate 5. A through hole 7 is provided on the first substrate 2 for each pad 6. A via hole groove 8 is provided on the first protective film 1, the second protective film 3, and the third protective film 4 above or below each through hole 7.
[0022] Each through hole 7 and via hole groove 8 is elliptical, and the projection of its contour falls inside the contour edge of a pad 6 on the second substrate 5.
[0023] In the utility model, by replacing the conventional round holes or square holes with the elliptical through holes 7 and via hole grooves 8, the area for accommodating solder paste can be enlarged without affecting the circuits on the substrate, thereby increasing the contact area between the solder paste and the pads 6 on the second substrate 5, ensuring a stable contact connection between the two. Moreover, the smooth surfaces of the through holes 7 and via hole grooves 8 without sharp corners facilitate the smooth flow of the solder paste and completely discharge the gas, avoiding the problem of internal solder joint voids caused by gas retention in the solder paste, improving the welding quality, and having little influence on the solder paste brushing effect and welding effect with different moving directions and angles of the solder paste brushing blade, being applicable to most solder paste brushing devices.
[0024] Furthermore, the contour edge of each via hole groove 8 falls outside the contour edge of a through hole 7.
[0025] It can be understood that, as Figure 1 shown, when the via hole groove 8 on the first board 1 is filled with solder paste, the solder paste can completely fill the relatively smaller through hole 7, thereby ensuring continuous and stable contact between the pad 6 on the first substrate 2 and the solder paste.
[0026] Furthermore, the central axes of the two pairwise - matching pads 6 on the first substrate 2 and the second substrate 5 coincide, and coincide with the central axes of a plurality of via hole grooves 8 at both ends thereof.
[0027] It can be understood that the setting of the coincident central axes facilitates the processing of the via hole grooves 8 and through holes 7, and can effectively utilize the solder paste to ensure complete contact between the solder paste and the two pads 6.
[0028] Furthermore, the area of each via hole groove 8 on the first protective film 1 and the second protective film 3 is 1.8 to 2.5 times the area of the through hole 7 communicated therewith, and the area of each pad 6 on the second substrate 5 is 1.5 to 2.0 times the area of the via hole groove 8 communicated therewith.
[0029] It can be understood that the area of the conduction guide groove 8 and the through hole 7 of appropriate size on the pad 6 can ensure that the second pad 6 can contact with a sufficient amount of solder paste, thus ensuring the stability of the electrical connection between the two pads, and can also ensure that the solder paste can fill the through-hole groove 8 without overflowing. In this embodiment, the size of the through-hole groove 8 is 3.8*1.8 mm, the size of the through hole 7 is 2.7*1.0 mm, and the size of the pad 6 is 1.5*2.8 mm.
[0030] The above does not impose any limitation on the technical scope of the present utility model. Any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.
Claims
1. Anti-false soldering structure on FPC. Two single-sided boards are overlapped on the FPC. On each single-sided board, connected circuits and several pads are printed or etched. Solder paste can pass through the upper single-sided board and contact and connect with the lower single-sided board to conduct the pads on the two single-sided boards in pairs. It is characterized in that: The FPC includes a first protective film, a first substrate, a second protective film, a third protective film and a second substrate from top to bottom. Several pads are provided on the first substrate and the second substrate. A through hole is provided on the first substrate for each pad. A via hole groove is provided on the first protective film, the second protective film and the third protective film above or below each through hole. Each through hole and via hole groove is oval, and the contour projection thereof all falls inside the contour edge of a pad on the second substrate.
2. The anti-false soldering structure on the FPC according to claim 1, characterized in that, The contour edge of each via hole groove falls outside the contour edge of a through hole.
3. The anti-false soldering structure on the FPC according to any one of claims 1-2, characterized in that The central axes of the pads that are pairwise matched on the first substrate and the second substrate coincide, and coincide with the central axes of several via hole grooves at both ends thereof.
4. The anti-false soldering structure on the FPC according to claim 3, wherein The area of each via hole groove on the first protective film and the second protective film is 1.8 to 2.5 times the area of the through hole communicated therewith.
5. The anti-false soldering structure on the FPC according to claim 3, characterized in that, The area of each pad on the second substrate is 1.5 to 2.0 times the area of the via hole groove communicated therewith.