Process-edge-free circuit board packaging method

Abstract

The invention discloses a process-edge-free circuit board packaging method, which comprises the following steps: providing a mold combination which comprises an upper mold and a lower mold, and the lower mold comprises a molding cavity with an upward opening and a side wall surrounding the molding cavity; a hard belt body is attached to the edge of one face surrounding the circuit board, the outer edge of the hard belt body outwards exceeds the outer edge of the circuit board, and the hard belt body is opposite to the face, to be sealed, of the circuit board. The circuit board pasted with the hard belt body is positioned and fixed to an upper mold, and the face, to be sealed, of the circuit board is exposed downwards; the liquid glue is output to a forming cavity; the upper mold and the lower mold are closed, the face, to be subjected to glue sealing, of the circuit board is immersed in the liquid glue, and the part, outwards exceeding the circuit board, of the hard belt body is clamped between the upper mold and the lower mold; after the liquid glue is cured, opening the upper mold and the lower mold, and taking out the circuit board with the glue sealing layer; and removing the hard belt body. According to the invention, the plane consistency of the sealing glue layer after the circuit board without the process edge is packaged can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of circuit board packaging, and in particular to a circuit board packaging method without process edges. Background Art

[0002] In recent years, as the cost of LED light board (usually PCB board) packaging continues to decrease, only some simple jigs can be used to fill the product with glue for LED light board packaging without process edges. The current common method includes filling the packaging area of ​​the circuit board with glue after damming it, and then pressing the circuit board and the packaging glue for several hours at room temperature before plasticizing and forming. However, this method has problems: First, the surface consistency of the product sealing layer obtained after the dam filling is poor. Second, the room temperature curing glue has a curing time of dozens of hours when the ambient temperature is high, and can be extended to dozens of hours when the ambient temperature is low, which seriously affects efficiency and production capacity. Summary of the invention

[0003] The purpose of the present application is to provide a circuit board packaging method without process edges, which can solve the technical problem of poor plane consistency of the product sealing layer after packaging the circuit board without process edges in the background technology.

[0004] In order to achieve the above object, the present application provides a circuit board packaging method without process edges, comprising:

[0005] Providing a mold assembly, the mold assembly comprising an upper mold and a lower mold, wherein the lower mold comprises a molding cavity opening upward and a side wall surrounding the molding cavity;

[0006] A hard belt body is attached around the edge of one side of the circuit board, the outer edge of the hard belt body extends outward beyond the outer edge of the circuit board, and the hard belt body is opposite to the side of the circuit board to be sealed with glue;

[0007] Positioning and fixing the circuit board with the hard belt attached to the upper mold, wherein the side of the circuit board to be sealed is exposed downward;

[0008] Outputting liquid glue to the molding cavity;

[0009] The upper mold and the lower mold are closed together, wherein the side of the circuit board to be sealed with glue is immersed in the liquid glue, and the portion of the hard belt body that extends outward beyond the outer edge of the circuit board is sandwiched between the side walls of the upper mold and the lower mold;

[0010] After the liquid glue is completely solidified, the upper mold and the lower mold are opened to take out the circuit board provided with the sealing glue layer;

[0011] The hard belt body is removed.

[0012] Optionally, the thickness error of the hard belt body is at micron level.

[0013] Optionally, the hard belt body is an adhesive tape.

[0014] Optionally, a portion of the hard belt body that extends outward beyond the outer edge of the circuit board is provided with a plurality of positioning holes, and the upper mold is provided with positioning pins corresponding to the positioning holes, and the circuit board is positioned on the upper mold by passing the positioning pins through the positioning holes.

[0015] Optionally, the upper mold has a vacuum flow channel, and the vacuum flow channel absorbs and fixes the circuit board on the upper mold through vacuum extraction.

[0016] Optionally, the upper mold and the lower mold are arranged in an openable and closable vacuum cavity;

[0017] After the liquid glue is output to the molding cavity, the vacuum cavity is closed and evacuated to remove bubbles in the liquid glue.

[0018] Optionally, the hard belt body is made of high temperature resistant material.

[0019] Optionally, the method further comprises:

[0020] When the liquid glue is solidified, the mold assembly is heated so that the heat is transferred to the liquid glue.

[0021] Optionally, after mold closing, a gap is formed between the outer edge of the circuit board and the inner surface of the side wall, and the liquid glue fills the gap; after removing the hard belt body, the residual glue portion that extends outwardly beyond the outer edge of the circuit board is removed.

[0022] Optionally, the residual glue portion extending outwardly beyond the outer edge of the circuit board is removed by cutting or milling.

[0023] In the embodiment of the present application, the sealant is sealed by the upper mold and the lower mold, and when the molds are closed, the hard belt body is sandwiched between the molds, not the circuit board itself. The overall thickness of the sealant layer is only affected by the flatness of the mold surface and the thickness consistency of the hard belt body. Therefore, by selecting a hard belt body with good thickness consistency, the thickness tolerance of the sealant layer can be effectively reduced, so that the sealant layer has better plane consistency, that is, the packaging method of the embodiment of the present application can effectively improve the plane consistency of the sealant layer after the circuit board without process edges is packaged. In addition, since the mold closing pressure is basically concentrated on the hard belt body on the side of the product, the periphery of the product is basically not subjected to force, which is conducive to avoiding damage to the product caused by the mold closing pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a circuit board packaging method without process edges according to an embodiment of the present application.

[0025] Figure 2 This is a top view of a hard tape attached to a circuit board according to an embodiment of the present application.

[0026] Figure 3 This is a side view of a hard tape attached to a circuit board according to an embodiment of the present application.

[0027] Figure 4 This is a schematic diagram of the circuit board in the embodiment of the present application being positioned and fixed to the upper mold and the lower mold after glue is dispensed.

[0028] Figure 5 This is a schematic diagram of the upper mold and the lower mold after they are molded together according to an embodiment of the present application.

[0029] Figure 6 This is a schematic diagram of the upper mold and the lower mold after mold opening according to an embodiment of the present application.

[0030] Figure 7 This is a schematic diagram of the packaged product after being removed from the upper mold according to an embodiment of the present application.

[0031] Figure 8 for Figure 7 Schematic diagram of the product after removing the hard belt body.

[0032] Fig. 9 for Figure 8 Schematic diagram of the product after removing residual glue. DETAILED DESCRIPTION

[0033] In order to explain the technical content, structural features, achieved objectives and effects of the present application in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0034] See also Figures 1 to 9 The present application discloses a circuit board packaging method without process edges. In the specific example of the attached drawings, the object of the packaging method is an LED light board. However, the packaging method is not limited to packaging LED light boards.

[0035] The packaging method includes:

[0036] S1 , providing a mold assembly, the mold assembly comprising an upper mold 1 and a lower mold 2 , wherein the lower mold 2 comprises a molding cavity 21 opening upward and a side wall 22 surrounding the molding cavity 21 .

[0037] S2, a hard belt 4 is attached around the edge of one side of the circuit board 3 (without process edge), the outer edge of the hard belt 4 extends outward beyond the outer edge of the circuit board 3, and the hard belt 4 is opposite to the side of the circuit board 3 to be sealed with glue.

[0038] The side of the circuit board 3 on which the hard tape 4 is attached is opposite to the side to be sealed with glue.

[0039] In some embodiments, the hard belt body 4 is made of adhesive tape, and is directly attached to the circuit board 3 by utilizing the adhesiveness of the adhesive tape. Of course, the hard belt body 4 is not limited to adhesive tape, and may also be other forms of hard belt body 4, such as a thin frame.

[0040] In order to ensure the technical effect, it is necessary to ensure that the hard belt 4 is attached around the circuit board 3 without any gap.

[0041] In some embodiments, the circuit board 3 is rectangular as a whole, and the hard belt body 4 on the circuit board 3 is in a U-shape as a whole. The four sides (including the four corners) of the U-shaped hard belt body 4 have no gaps, and the heights of the four sides are equal.

[0042] S3, positioning and fixing the circuit board 3 with the hard belt 4 attached to the upper mold 1, wherein the side of the circuit board 3 to be sealed is exposed downward.

[0043] After the hard tape body 4 is attached, the circuit board 3 with the hard tape body 4 attached can be assembled to the upper mold 1 .

[0044] Specifically, in order to assemble the circuit board 3 , the upper mold 1 is provided with recesses for avoiding the electronic components on the surface of the circuit board 3 (opposite to the side to be sealed).

[0045] In some embodiments, the portion of the hard belt body 4 that extends outward beyond the outer edge of the circuit board 3 is provided with a plurality of positioning holes 41, and the upper mold 1 is provided with positioning pins 11 corresponding to the positioning holes 41, and the circuit board 3 is positioned on the upper mold 1 by passing the positioning pins 11 through the positioning holes 41. The cooperation between the positioning pins 11 and the positioning holes 41 can realize the rapid positioning of the circuit board 3 with the hard belt body 4 attached.

[0046] In the specific example, the circuit board 3 is rectangular as a whole, the hard belt body 4 on the circuit board 3 is square as a whole, and the positioning holes 41 are respectively formed at the four corners of the hard belt body 4, but it is certainly not limited to this.

[0047] In some embodiments, the upper mold 1 has a vacuum flow channel (not shown), and the vacuum flow channel absorbs and fixes the circuit board 3 on the upper mold 1 by vacuuming.

[0048] Specifically, the upper mold 1 and the lower mold 2 are installed inside the device, and the vacuum channel of the upper mold 1 can be evacuated inside the device.

[0049] S4, outputting the liquid glue to the molding cavity 21.

[0050] Specifically, after the circuit board 3 waiting for sealing is fixed to the upper mold 1, the glue dispensing mechanism can be used for glue dispensing. When the required glue meets the quality requirements, the glue dispensing stops, and the glue is in liquid state in the lower mold 2.

[0051] More specifically, the dispensing mechanism may be disposed inside the overall device, but is not limited thereto.

[0052] It should be noted that outputting the liquid glue to the molding cavity 21 is not limited to after the circuit board 3 waiting for the glue sealing is fixed to the upper mold 1, that is, there is no absolute order between step S3 and step S4. Figure 1 The flowchart in the figure is only for the convenience of intuitive understanding of the present application, and the present application is not limited to Figure 1 The execution order in .

[0053] In some embodiments, the upper mold 1 and the lower mold 2 are arranged in an openable and closable vacuum cavity; after the liquid glue is output to the molding cavity 21, the vacuum cavity is closed and evacuated to remove bubbles in the liquid glue. By evacuating the bubbles in the liquid glue, defects caused by the bubbles can be avoided.

[0054] After the bubble removal operation is completed, the upper mold 1 and the lower mold 2 can be closed to perform the sealing operation.

[0055] S5, the upper mold 1 and the lower mold 2 are closed, wherein the side of the circuit board 3 to be sealed is immersed in liquid glue, and the part of the hard belt 4 that extends outward beyond the outer edge of the circuit board 3 is clamped between the side walls 22 of the upper mold 1 and the lower mold 2.

[0056] Since the portion of the hard belt body 4 that extends outward beyond the outer edge of the circuit board 3 is sandwiched between the side walls 22 of the upper mold 1 and the lower mold 2, that is, after the upper mold 1 and the lower mold 2 are closed under pressure, the closing pressure is basically concentrated on the hard belt body 4 on the side of the product, so that the periphery of the product is basically not subjected to force, which is conducive to avoiding damage to the product caused by the closing pressure. In addition, the hard belt body 4 is configured with good thickness consistency. For example, when using tape, the tape generally has good thickness consistency, with only a micron-level height difference. In this way, the portion of the hard belt body 4 that extends outward beyond the outer edge of the circuit board 3 is sandwiched between the side walls 22 of the upper mold 1 and the lower mold 2, and the thickness tolerance of the sealing layer 5 on the molded product is small, and the plane consistency is good.

[0057] S6, after the liquid glue is completely solidified, the upper mold 1 and the lower mold 2 are opened, and the circuit board 3 with the sealing glue layer 5 is taken out.

[0058] In some embodiments, when the liquid glue is solidified, the mold assembly is heated to transfer the heat to the liquid glue. By heating the mold assembly and transferring the heat to the liquid glue, the solidification time of the liquid glue can be effectively reduced, thereby increasing production capacity.

[0059] Under heating conditions, liquid glue can be solidified in a few minutes, greatly improving production capacity.

[0060] How to achieve heating is not the focus of this application, as long as the purpose of accelerating curing can be achieved. Existing heating means can be used. For example, a heating control system can be set in the mold mounting plate. For details, please refer to the patent number 202420127655.4, and the patent name is a heating control system disclosed in the patent for vacuum molding and plastic sealing mechanism suitable for LED light board module and semiconductor chip packaging.

[0061] It is understandable that in order to adapt to curing under heating conditions, the hard belt body 4 needs to be able to withstand high temperatures, and a high temperature resistant material can be directly used.

[0062] Specifically, after curing for a period of time, the upper mold 1 and the lower mold 2 can be opened. At this time, the cured sealing layer 5 on the surface of the product is fixed on the upper mold 1 along with the product itself. Then, the product with the cured sealing layer 5 can be taken out by removing the vacuum.

[0063] S7, removing the hard belt body 4.

[0064] After taking out the product, the hard belt body 4 on the product can be removed.

[0065] In some embodiments, after the mold is closed, a gap is formed between the outer edge of the circuit board 3 and the inner surface of the side wall 22, and the liquid glue is filled to the gap A. After removing the hard belt 4, the residual glue portion that exceeds the outer edge of the circuit board 3 (i.e., the glue solidified at the position corresponding to the gap A) is removed. After the residual glue is removed, a packaged product can be obtained.

[0066] In the embodiment of the present application, the sealant is sealed by the upper mold 1 and the lower mold 2, and when the molds are closed, the hard belt body 4 is sandwiched between the molds, not the circuit board 3 itself, and the overall thickness of the sealant layer 5 is only affected by the flatness of the mold surface and the thickness consistency of the hard belt body 4. Therefore, by selecting a hard belt body 4 with good thickness consistency, the thickness tolerance of the sealant layer 5 can be effectively reduced, so that the sealant layer 5 has better plane consistency, that is, the packaging method of the embodiment of the present application can effectively improve the plane consistency of the sealant layer 5 after the circuit board 3 without process edges is packaged. In addition, since the mold closing pressure is basically concentrated on the hard belt body 4 on the side of the product, the periphery of the product is basically not subjected to force, which is conducive to avoiding damage to the product caused by the mold closing pressure.

[0067] The following is a comparison between the prior art and the embodiments of the present application, and further describes the technical effects of the embodiments of the present application in detail.

[0068] 1. The existing dam dispensing process and fixture are relatively complicated in the packaging process, and the process is relatively cumbersome. Since the required fixture corresponds to the product, one fixture is required for one product. The circuit board packaging method without process edges of the embodiment of the present application is based on packaging of circuit boards without process edges. The process is relatively simple. The plastic sealing can be completed by installing the mold, and it is convenient for loading and unloading, and only one set of mold combination is required to complete it.

[0069] 2. The dam glue dispensing process has low production requirements, resulting in poor consistency in the thickness of the sealing layer after packaging, which cannot be applied to high-end products in industries such as optical display modules. The circuit board packaging method without process edges in the embodiment of the present application is completed by plastic sealing inside the mold, and the overall thickness of the sealing layer 5 is only affected by the flatness of the mold surface and the consistency of the thickness of the hard belt body 4. For example, when the hard belt body 4 uses a tape, the thickness consistency of the tape is usually very good and can meet the thickness tolerance requirements of the sealing layer at the micron level.

[0070] 3. Compared with the glue dispensing packaging with process edges, high-precision cutting is still required after the molding process to complete the product trimming, and the module products with process edges will eventually have the process edges cut off, which causes serious waste of production costs and environmental pollution in the case of large-scale production. The circuit board packaging method without process edges in the embodiment of the present application directly solves the requirement of high-precision plastic sealing when there is no process edge, which can not only meet the high-standard quality requirements of the product, but also reduce the cost waste and environmental pollution caused by the process edge.

[0071] 4. The dam glue dispensing process for products without process edges can only be applied to low-end products. The glue dispensing and plastic sealing of products with process edges has a relatively high cost and a relatively narrow application range. However, the circuit board packaging method without process edges in the embodiment of the present application can be used in a wide range of products, which will improve the overall plastic sealing quality of the industry and further reduce the cost of product production.

[0072] 5. The glue dispensing process for the product dam without process edges, the single-piece output cycle is calculated in days, ranging from 1 day to 2-3 days. The production time cycle is very long, and the circuit board packaging method without process edges in the embodiment of the present application is simple in glue dispensing molding. Under the condition of heating setting, the single-piece molding time can be achieved in just a few minutes, achieving efficient output, which can greatly reduce the cost of the product.

[0073] 6. The glue dispensing process for the dam of products without process edges and the glue dispensing and plastic sealing of products with process edges both have long production cycles and complex processes, and the corresponding requirements for on-site technicians and equipment configuration are relatively high, which indirectly increases the user's use cost and potential product quality risks caused by technical debugging. The circuit board packaging method without process edges in the embodiment of the present application is relatively simple to implement, easy to debug, operate, and maintain, and reduces the user's production cost.

[0074] 7. The glue dispensing process for the product dam without process edges will produce excessive irregular glue overflow during the production process, and finally cut off before the product is formed, resulting in a large amount of glue waste and environmental pollution. However, in the circuit board packaging method without process edges of the embodiment of the present application, the product and the hard belt body 4 are fixed and embedded in the molding cavity 21 of the lower mold 2. After molding, glue overflow (the aforementioned residual glue) will be generated on the side, but the shape is regular, the amount of glue overflow is controllable, and the waste is small.

[0075] 8. The sealing layer of the plastic-sealed product itself needs to be under heavy pressure to ensure that the gaps between the product components are filled firmly. For example, when the circuit board is an LED light board, it is necessary to ensure that the gaps between the lamp beads and the gaps between the lamp beads and the pads are filled firmly. However, after the product dam without process edges is glued, the gravity of the weights is used to squeeze the glue on the surface of the product. Although there is pressure, under excessive pressure, the glue will be squeezed to the four sides of the product because it is not constrained by the frame in the horizontal direction. The circuit board packaging method without process edges in the embodiment of the present application is a kind of thermal curing plastic sealing performed inside the mold. After the amount of glue is determined, different pressures (whether kilograms or tonnage) can be adjusted to flexibly respond to the packaging of the product, and at the same time, the gaps between the components can be completely filled with glue under heavy pressure. At the same time, it is ensured that the glue does not overflow, and the pressure is appropriately increased. The density of the product during the plastic sealing process can be microscopically improved, and the life of the product during outdoor use can be improved.

[0076] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the patent scope of the present application are still within the scope covered by the present application.

Claims

1. A circuit board packaging method without process edges, characterized in that: include: Providing a mold assembly, the mold assembly comprising an upper mold and a lower mold, wherein the lower mold comprises a molding cavity opening upward and a side wall surrounding the molding cavity; A hard belt body is attached around the edge of one side of the circuit board, the outer edge of the hard belt body extends outward beyond the outer edge of the circuit board, and the hard belt body is opposite to the side of the circuit board to be sealed with glue; Positioning and fixing the circuit board with the hard belt attached to the upper mold, wherein the side of the circuit board to be sealed is exposed downward; Outputting liquid glue to the molding cavity; The upper mold and the lower mold are closed together, wherein the side of the circuit board to be sealed with glue is immersed in the liquid glue, and the portion of the hard belt body that extends outward beyond the outer edge of the circuit board is sandwiched between the side walls of the upper mold and the lower mold; After the liquid glue is completely solidified, the upper mold and the lower mold are opened to take out the circuit board provided with the sealing glue layer; The hard belt body is removed.

2. The circuit board packaging method without process edges according to claim 1, characterized in that: The thickness error of the hard belt body is at micron level.

3. The circuit board packaging method without process edges according to claim 1 or 2, characterized in that: The hard belt body is an adhesive tape.

4. The circuit board packaging method without process edges according to claim 1, characterized in that: The portion of the hard belt body that extends outward beyond the outer edge of the circuit board is provided with a plurality of positioning holes, and the upper mold is provided with positioning pins corresponding to the positioning holes. The circuit board is positioned on the upper mold by passing the positioning pins through the positioning holes.

5. The circuit board packaging method without process edges according to claim 1, characterized in that: The upper mold has a vacuum flow channel, and the vacuum flow channel absorbs and fixes the circuit board on the upper mold through vacuuming.

6. The circuit board packaging method without process edges according to claim 1, characterized in that: The upper mold and the lower mold are arranged in a vacuum cavity that can be opened and closed; After the liquid glue is output to the molding cavity, the vacuum cavity is closed and evacuated to remove bubbles in the liquid glue.

7. The circuit board packaging method without process edges according to claim 1, characterized in that: The hard belt body is made of high temperature resistant material.

8. The circuit board packaging method without process edges as claimed in claim 1, characterized in that: Also includes: When the liquid glue is solidified, the mold assembly is heated so that the heat is transferred to the liquid glue.

9. The circuit board packaging method without process edges according to claim 1, characterized in that: After the mold is closed, a gap is formed between the outer edge of the circuit board and the inner surface of the side wall, and the liquid glue is filled into the gap; After removing the hard belt body, remove the residual glue portion that extends outwardly beyond the outer edge of the circuit board.

10. The circuit board packaging method without process edges according to claim 9, characterized in that: The residual glue portion that extends outwardly beyond the outer edge of the circuit board is removed by cutting or milling.

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