FPC backlight strip and 3D printing embedded process thereof

Abstract

This invention discloses an FPC backlight strip and its 3D printing embedded process. The FPC backlight strip includes a 3D printable substrate layer; embedded circuitry, located inside the substrate layer and forming three-dimensional traces; pads located at the ends of bare copper traces; a cover film layer, adhered to the surface of the substrate layer, with clearance holes corresponding to the pad positions; and LED beads and resistors, mounted on the pads using solder paste. The 3D printing embedded process includes S1, circuit design; S2, substrate preparation; S3, 3D embedded wire forming; S4, cover film lamination; S5, high-temperature pressing; and S6, die-cutting. Advantages: This invention uses a physical embedding method to replace the traditional chemical etching process, completely eliminating the processes of photosensitive film lamination, exposure, development, and etching. It requires no chemical reagents, completely eliminating the environmental pollution problem caused by etching waste liquid, and is a green and environmentally friendly manufacturing technology that can reduce environmental pollution and improve manufacturing precision.

Description

Technical Field

[0001] This invention relates to the field of electronics, specifically to an FPC backlight strip and its 3D printing embedded process. Background Technology

[0002] The traditional manufacturing process for FPC backlight strips mainly involves two steps. The first step is: pressing a photosensitive film onto copper foil → film alignment → exposure → development → etching → applying solder resist PI film → high-temperature bonding → surface treatment → die-cutting to form the FPC. The second step is: printing solder paste onto the FPC → lighting → sealing → applying adhesive backing to form the finished product. This manufacturing process is cumbersome, especially the first three steps of exposure, development, and etching, which not only consume a lot of time but also use expensive reagents and cause environmental pollution.

[0003] For example, Chinese invention patent CN110087398A discloses a novel method for manufacturing FPCs. This technical solution uses a copper-nickel substrate and a nickel substrate to form a composite substrate through heating and rolling. Then, circuitry is formed through single-sided lamination, exposure, development, and etching processes. Finally, the FPC is manufactured through steps such as applying a cover film and SMT assembly. This method achieves direct welding between the FPC and the battery cell using copper-nickel composite materials, simplifying the traditional process of bridging with nickel sheets. This saves labor and processing costs to some extent, improving production efficiency. However, although this prior art (CN110087398A) improves the material composite method, its core circuit forming process still uses traditional exposure, development, and etching techniques. In particular, in step S3, this solution still requires "exposing, developing, and etching the coil circuitry after applying the dry film, and removing excess dry film." This means that this technical solution still cannot escape dependence on chemical reagents such as photosensitive film, developer, and etching solution, and its improvement in environmental protection and process simplification is limited. Meanwhile, the etching process itself has technical bottlenecks such as difficulty in controlling linewidth uniformity, difficulty in completely avoiding side etching, and limited yield of fine lines. In addition, the treatment cost of etching waste liquid is high, which puts continuous pressure on environmental protection.

[0004] Therefore, it is necessary to provide an FPC backlight strip and its 3D printing embedded process. Summary of the Invention

[0005] The present invention provides an FPC backlight strip and its 3D printing embedded process, which effectively solves the problems of complex and high cost of existing FPC backlight strip manufacturing processes.

[0006] The technical solution adopted in this invention is: a 3D printing embedded process, comprising the following steps, S1. Circuit design: The path of copper wires is designed and planned using software. S2. Substrate preparation: Cut the 3D printable substrate to the required dimensions to meet product specifications. S3, 3D embedded wire molding, uses 3D printing automatic embedded wire equipment to embed bare copper wires into the substrate layer by layer according to the design path to form a three-dimensional circuit, and forms a pad structure for subsequent mounting by coiling copper wires at the predetermined terminal position of the circuit. S4. Cover film bonding: The cover film with pre-punched pad clearance holes is bonded to the surface of the substrate after the wire embedding is completed. S5. High-temperature pressing: High-temperature pressing is performed at 170-180℃ to tightly bond the cover film to the substrate and completely encapsulate the bare copper wires between the substrate and the cover film. S6, punching: using a steel die to punch the pressed semi-finished product into a preset shape structure; S7. Surface mount technology: Solder paste is printed on the pads, and LED chips and resistors are packaged using SMT equipment.

[0007] Furthermore, it also includes S8 and post-processing, which involves drying the packaged product in a solder pot and attaching adhesive backing and gold fingers.

[0008] Furthermore, the substrate after slitting in S2 needs to be cleaned and dried.

[0009] Furthermore, in S3, while printing the substrate, the 3D printing wire embedding device pauses plastic printing at the layer height where the wire needs to be embedded. The bare copper wire is automatically laid into the groove reserved on the substrate through the wire embedding head of the 3D printing device, and then the upper substrate is printed to achieve full-coverage encapsulation of the circuit.

[0010] Furthermore, in S3, the solder pads are formed by controlling the buried wire head to spiral or stack the wires at the end of the buried wire path, so that the bare copper wires form a planar spiral or raised contact structure, which serves as the carrier for subsequent solder paste printing.

[0011] Furthermore, the punching and bonding of the cover film in S4 specifically includes: firstly, punching out clearance holes on the cover film using a mold, which correspond one-to-one with the positions of the solder pads in step S3; then, bonding the cover film with clearance holes to the surface of the substrate using an automatic bonding device, so that the solder pads are exposed from the clearance holes.

[0012] Furthermore: In S7, the solder paste is printed using a stencil printing method, and the solder paste is precisely applied to the pads formed by the coiled copper wires through the clearance holes of the cover film.

[0013] Furthermore, step S8 specifically includes: first, punching the adhesive backing to form clearance holes corresponding to the positions of the LED beads and resistors, and then using a film-applying device to apply the adhesive backing to the product surface.

[0014] Furthermore, step S8 specifically includes attaching the gold fingers: attaching the conductive gold fingers to a designated area of ​​the product's assembly part, and electrically connecting the gold fingers to the exposed copper wire terminals.

[0015] An FPC backlight strip, employing the aforementioned 3D printing embedded process, includes a 3D printable substrate layer; embedded circuitry composed of bare copper wires with a diameter of 0.1-0.15mm, the bare copper wires being completely embedded within the substrate layer to form a three-dimensional trace; pads located at the ends of the bare copper wires, consisting of a spiral protrusion structure formed by coiled copper wires; a cover film layer adhered to the surface of the substrate layer, with clearance holes corresponding to the pad positions; and LED beads and resistors mounted on the pads using solder paste.

[0016] Beneficial effects of the invention: 1. This invention uses a physical embedding method to replace the traditional chemical etching process, completely eliminating the processes of photosensitive film lamination, exposure, development, and etching. It does not require the use of any chemical reagents, thus completely eliminating the environmental pollution problem caused by etching waste liquid. It is a green and environmentally friendly manufacturing technology that can reduce environmental pollution and improve preparation accuracy.

[0017] 2. Compared to the traditional FPC process which requires more than ten complex steps, this invention integrates the circuit forming process into a one-step 3D embedded wire forming process, eliminating high-cost and time-consuming steps such as exposure, development, and etching, significantly shortening the production cycle, reducing equipment investment and reagent costs, and reducing the overall manufacturing cost by more than 30%.

[0018] 3. This invention uses bare copper wires directly embedded inside the substrate to form a three-dimensional circuit. Compared with the planar copper foil circuit formed by traditional etching, the embedded copper wires have better conductivity and bending resistance. The spiral pad structure formed by the coiled copper wires increases the welding area and improves the adhesion of the solder joints. The fully encapsulated packaging structure makes the circuit tightly bonded to the substrate, avoiding reliability problems such as circuit peeling and breakage.

[0019] 4. This invention achieves three-dimensional wiring of circuits through 3D printing technology, which allows for free routing of lines at different layer heights on the substrate. This breaks through the limitation of traditional FPCs being limited to planar wiring, greatly improving the design flexibility and space utilization of backlight strips. At the same time, the position and size of the pads can be flexibly controlled by adjusting the number of rotations according to actual needs, adapting to the mounting requirements of LED beads and resistors of different specifications. Attached Figure Description

[0020] Figure 1 A flowchart of the 3D printing embedded process provided for embodiments of this application.

[0021] Figure 2 This is a schematic diagram of an FPC backlight strip provided for an embodiment of this application.

[0022] The markings in the diagram are: 1. Substrate layer; 2. Embedded circuit; 3. Cover film; 4. Adhesive backing; 5. LED beads; 6. Gold fingers. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] like Figure 2 As shown, the first embodiment provided in this application is a 3D printing embedded process, which includes the following steps: S1. Circuit design: The path of copper wires is designed and planned using software. S2. Substrate preparation: Cut the 3D printable substrate to the required dimensions to meet product specifications. S3, 3D embedded wire molding, uses 3D printing automatic embedded wire equipment to embed bare copper wires into the substrate layer by layer according to the design path to form a three-dimensional circuit, and forms a pad structure for subsequent mounting by coiling copper wires at the predetermined terminal position of the circuit. S4. Cover film bonding: The cover film with pre-punched pad clearance holes is bonded to the surface of the substrate after the wire embedding is completed. S5. High-temperature pressing: High-temperature pressing is performed at 170-180℃ to tightly bond the cover film to the substrate and completely encapsulate the bare copper wires between the substrate and the cover film. S6, punching: using a steel die to punch the pressed semi-finished product into a preset shape structure; S7. Surface mount technology: Solder paste is printed at the pad positions, and LED chips and resistors are packaged using SMT equipment. In the above design, the process of this application uses copper wire directly embedded in the substrate, making the fabrication process more environmentally friendly and pollution-free. The entire fabrication process is simple and can reduce manufacturing costs.

[0025] Specifically, it also includes S8 and post-processing, which involves drying the packaged product in a solder pot and attaching the adhesive backing and gold fingers.

[0026] In the above design, the encapsulated product undergoes a solder pot drying process, which facilitates product molding. The adhesive backing facilitates bonding of the product to external objects, and the gold fingers enable easy interconnection and communication between the product and external circuitry.

[0027] Specifically: the substrate after slitting in S2 needs to be cleaned and dried.

[0028] In the above design, cleaning and drying the substrate after slitting ensures that the substrate surface is clean, free of water stains and dust, and ensures product quality during subsequent processing.

[0029] Specifically: In S3, while printing the substrate, the 3D printing wire embedding device pauses plastic printing at the layer height where the wire needs to be embedded. The bare copper wire is automatically laid into the groove reserved on the substrate through the wire embedding head of the 3D printing device. Then, the upper substrate is printed to achieve full-coverage encapsulation of the circuit.

[0030] In the above design, by pre-reserving grooves on the substrate, the copper wires can be embedded into the substrate more precisely.

[0031] Specifically: In S3, the solder pad is formed by controlling the buried wire head to spiral or stack the wires at the end of the buried wire path, so that the bare copper wire forms a planar spiral or raised contact structure, which serves as the carrier for subsequent solder paste printing.

[0032] In the above design, the formation process of the solder pads can serve as a carrier for subsequent solder paste printing, ensuring that the subsequent solder paste can adhere strongly to the product.

[0033] Specifically, the punching and bonding of the cover film in S4 includes: first, punching out clearance holes on the cover film using a mold that correspond one-to-one with the positions of the solder pads in step S3; then, bonding the cover film with clearance holes to the surface of the substrate using an automatic bonding device, so that the solder pads are exposed from the clearance holes.

[0034] In the above design, a die is used during punching to ensure product forming accuracy and guarantee the size and position of the clearance holes. The use of automated film lamination equipment in the covering film lamination process not only saves labor costs but also improves lamination accuracy.

[0035] Specifically: In S7, the solder paste printing adopts an automatic printing method, and the solder paste is precisely coated onto the pads formed by the coiled copper wire through the clearance holes of the cover film.

[0036] In the above design, the solder paste is printed automatically using a printer, which ensures the accuracy of the solder paste printing and saves more time compared to manual operation.

[0037] Specifically, step S8, which involves bonding the adhesive backing, includes: first, punching the adhesive backing to form clearance holes corresponding to the positions of the LED beads and resistors, and then bonding the adhesive backing to the product surface using a film-applying device.

[0038] In the above design, the adhesive backing is first punched with clearance holes to accommodate the LED beads and resistors, which can prevent interference between the adhesive backing and the LED beads and resistors during subsequent bonding.

[0039] Specifically, step S8, which involves attaching the gold fingers, includes attaching the conductive gold fingers to a designated area of ​​the product's assembly part, and electrically connecting the gold fingers to the exposed copper wire terminals.

[0040] In the above design, the gold-plated fingers facilitate the product's docking with external devices during use.

[0041] like Figure 1 As shown, the second embodiment provided in this application is an FPC backlight strip that uses the aforementioned 3D printing embedded process. It includes a 3D printable substrate layer; embedded circuitry composed of bare copper wires with a diameter of 0.1-0.15mm, the bare copper wires being completely embedded within the substrate layer to form a three-dimensional trace; pads located at the ends of the bare copper wires, consisting of a spiral protrusion structure formed by coiled copper wires; a cover film layer adhered to the surface of the substrate layer, with clearance holes corresponding to the pad positions; and LED beads and resistors mounted on the pads using solder paste.

[0042] In the above design, the FPC backlight strip has a simple structure and is easy to manufacture.

[0043] The third embodiment provided in this application is a 3D printing embedded process, including the following steps: S1, circuit design, planning the path of copper wires through software design; S2, substrate preparation, cutting the 3D printable substrate to meet product specifications; S3, 3D wire embedding, using an automatic 3D printing wire embedding device, embedding bare copper wires layer by layer into the substrate according to the designed path to form a three-dimensional circuit, and forming pad structures for subsequent mounting by coiling copper wires at predetermined terminal positions of the circuit; S4, cover film bonding, bonding a cover film with pre-punched pad clearance holes to the surface of the substrate after wire embedding; S5, high-temperature pressing, performing high-temperature pressing at 170-180℃ to tightly bond the cover film to the substrate and completely encapsulate the bare copper wires between the substrate and the cover film; S6, punching, using a steel mold to punch the pressed semi-finished product into a preset shape structure; S7, surface mounting, printing solder paste at the pad positions, and encapsulating LED beads and resistors using SMT equipment. The process also includes S8, post-processing, which involves drying the packaged product in a solder bath and attaching the adhesive backing and gold fingers. In S2, the slit substrate undergoes cleaning and drying. In S3, the 3D printing wire embedding equipment pauses plastic printing at the required wire embedding layer height while printing the substrate. The wire embedding head of the 3D printing equipment automatically lays bare copper wires into pre-reserved grooves on the substrate, and then continues printing the upper substrate layer to achieve full-coverage encapsulation of the circuitry. In S3, the pads are formed by controlling the wire embedding head to spiral or stack the wires at the end of the embedding path, forming a planar spiral or raised contact structure on the bare copper wires. This structure serves as the carrier for subsequent solder paste printing. S4, the punching and bonding of the cover film, specifically includes: first, punching out clearance holes on the cover film corresponding to the pad positions in step S3 using a mold; then, bonding the cover film with the clearance holes to the substrate surface using an automatic bonding device, exposing the pads through the clearance holes. In step S7, solder paste printing is performed using a stencil printing method. The solder paste is precisely applied to the pads formed by the coiled copper wires through the clearance holes in the cover film. Step S8, applying the adhesive backing, specifically includes: first, punching the adhesive backing to form clearance holes corresponding to the positions of the LED beads and resistors, and then applying the adhesive backing to the product surface using a film-applying device. Step S8, applying the gold fingers, specifically includes: applying the conductive gold fingers to the designated area of ​​the product's assembly section, with the gold fingers electrically connected to the exposed copper wire terminals.

[0044] The above design has a simple structure and eliminates environmentally polluting steps such as developing and etching compared to existing processes. Furthermore, the use of 3D embedding makes the molding process more precise.

[0045] In further detail, it should be understood that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Figure 2 As shown, the first embodiment provided in this application is a 3D printing embedded process, which includes the following steps: S1. Circuit design: The path of copper wires is designed and planned using software. S2. Substrate preparation: Cut the 3D printable substrate to the required dimensions to meet product specifications. S3, 3D embedded wire molding, uses 3D printing automatic embedded wire equipment to embed bare copper wires into the substrate layer by layer according to the design path to form a three-dimensional circuit, and forms a pad structure for subsequent mounting by coiling copper wires at the predetermined terminal position of the circuit. S4. Covering film 3 is applied by applying the cover film 3, which has been pre-punched with pad clearance holes, to the surface of the substrate after the wire embedding is completed. S5. High-temperature pressing: High-temperature pressing is performed at 170-180℃ to tightly bond the cover film 3 with the substrate and completely encapsulate the bare copper wire between the substrate and the cover film 3. S6, punching: using a steel die to punch the pressed semi-finished product into a preset shape structure; S7. Surface mount, solder paste is printed at the pad positions, and LED beads and resistors are packaged using SMT equipment; In the above design, the process of this application uses copper wire directly embedded in the substrate, making the fabrication process more environmentally friendly and pollution-free. The entire fabrication process is simple and can reduce manufacturing costs.

[0046] Specifically, it also includes S8 and post-processing, which involves drying the packaged product in a solder pot and attaching the backing adhesive 4 and gold fingers 6.

[0047] In the above design, the encapsulated product undergoes a solder pot drying process, which facilitates product molding. The adhesive backing 4 facilitates bonding of the product to external objects, and the gold fingers 6 enable easy interconnection and communication between the product and external circuitry.

[0048] Specifically: the substrate after slitting in S2 needs to be cleaned and dried.

[0049] In the above design, cleaning and drying the substrate after slitting ensures that the substrate surface is clean, free of water stains and dust, and ensures product quality during subsequent processing.

[0050] Specifically: In S3, while printing the substrate, the 3D printing wire embedding device pauses plastic printing at the layer height where the wire needs to be embedded. The bare copper wire is automatically laid into the groove reserved on the substrate through the wire embedding head of the 3D printing device. Then, the upper substrate is printed to achieve full-coverage encapsulation of the circuit.

[0051] In the above design, by pre-reserving grooves on the substrate, the copper wires can be embedded into the substrate more precisely.

[0052] Specifically: In S3, the solder pad is formed by controlling the buried wire head to spiral or stack the wires at the end of the buried wire path, so that the bare copper wire forms a planar spiral or raised contact structure, which serves as the carrier for subsequent solder paste printing.

[0053] In the above design, the formation process of the solder pads can serve as a carrier for subsequent solder paste printing, ensuring that the subsequent solder paste can adhere strongly to the product.

[0054] Specifically, the punching and bonding of the cover film 3 in step S4 includes: first, punching out clearance holes on the cover film 3 through a mold that correspond one-to-one with the positions of the solder pads in step S3; then, bonding the cover film 3 with clearance holes to the surface of the substrate through an automatic bonding device, so that the solder pads are exposed from the clearance holes.

[0055] In the above design, a die is used during punching to ensure product forming accuracy and guarantee the size and position of the clearance holes. The automatic film application process for the cover film 3 saves labor costs and improves application accuracy.

[0056] Specifically: In S7, the solder paste is printed using an automatic printing machine. The solder paste is precisely applied to the pads formed by the coiled copper wires through the clearance holes of the cover film 3.

[0057] In the above design, the solder paste is printed automatically using a printer, which ensures the accuracy of the solder paste printing and saves more time compared to manual operation.

[0058] Specifically, step S8 of bonding the adhesive backing 4 includes: first, punching the adhesive backing 4 to form clearance holes corresponding to the positions of the LED beads 5 and the resistor, and then bonding the adhesive backing 4 to the product surface using a film bonding device.

[0059] In the above design, the adhesive backing 4 is first punched with clearance holes to accommodate the LED beads 5 and the resistor, which can prevent interference between the adhesive backing 4 and the LED beads 5 and the resistor when they are bonded together.

[0060] Specifically, step S8, which involves attaching the gold finger 6, includes attaching the conductive gold finger 6 to a designated area of ​​the product's assembly part, and electrically connecting the gold finger 6 to the exposed copper wire endpoints.

[0061] In the above design, the gold fingers 6 facilitate the product's connection with external devices during use.

[0062] like Figure 1 As shown, the second embodiment provided in this application is an FPC backlight strip that uses the aforementioned 3D printing embedded process. It includes a 3D printable substrate layer 1; an embedded circuit 2 composed of bare copper wires with a diameter of 0.1-0.15mm, the bare copper wires being completely embedded inside the substrate layer 1 to form a three-dimensional trace; solder pads located at the ends of the bare copper wires, consisting of a spiral protrusion structure formed by coiled copper wires; a cover film 3 layer adhered to the surface of the substrate layer 1, with clearance holes corresponding to the positions of the solder pads; and LED beads 5 and resistors mounted on the solder pads using solder paste.

[0063] In the above design, the FPC backlight strip has a simple structure and is easy to manufacture.

[0064] The third embodiment provided in this application is a 3D printing embedded process, including the following steps: S1, circuit design, planning the path of copper wires through software design; S2, substrate preparation, cutting the 3D printable substrate to meet product specifications; S3, 3D wire embedding, using an automatic 3D printing wire embedding device, embedding bare copper wires layer by layer into the substrate according to the designed path to form a three-dimensional circuit, and forming a pad structure for subsequent mounting by coiling copper wires at the predetermined terminal position of the circuit; S4, cover film 3 bonding, applying a cover film 3 pre-punched with pad clearance holes to the surface of the substrate after wire embedding; S5, high-temperature pressing, performing high-temperature pressing at 170-180℃ to tightly bond the cover film 3 to the substrate and completely encapsulate the bare copper wires between the substrate and the cover film 3; S6, punching, using a steel mold to punch the pressed semi-finished product into a preset shape structure; S7, surface mounting, printing solder paste at the pad positions, and encapsulating LED beads 5 and resistors using SMT equipment. It also includes S8, post-processing, which involves drying the packaged product in a solder bath and attaching the backing adhesive 4 and gold fingers 6. In S2, the slit substrate needs to be cleaned and dried. In S3, while printing the substrate, the 3D printing wire embedding equipment pauses plastic printing at the layer height where wire embedding is required. The wire embedding head of the 3D printing equipment automatically lays bare copper wires into pre-reserved grooves on the substrate, and then continues printing the upper substrate layer to achieve full-coverage encapsulation of the circuit. In S3, the pads are formed by controlling the wire embedding head to spiral or stack the wires at the end of the embedding path, forming a planar spiral or raised contact structure on the bare copper wires. This structure serves as the carrier for subsequent solder paste printing. In S4, the punching and bonding of the cover film 3 specifically includes: first, punching out clearance holes on the cover film 3 corresponding to the pad positions in step S3 using a mold; then, bonding the cover film 3 with clearance holes to the substrate surface using an automatic bonding equipment, exposing the pads through the clearance holes. In step S7, solder paste printing is performed using a stencil printing method. The solder paste is precisely applied to the pads formed by the coiled copper wires through the clearance holes in the cover film 3. Step S8, bonding the adhesive backing 4, specifically includes: first, punching the adhesive backing 4 to form clearance holes corresponding to the positions of the LED beads 5 and resistors; then, using a film-applying device, bonding the adhesive backing 4 to the product surface. Step S8, bonding the gold fingers 6, specifically includes: bonding the conductive gold fingers 6 to the designated area of ​​the product's assembly section; the gold fingers 6 are electrically connected to the exposed copper wire terminals.

[0065] The above design has a simple structure and eliminates environmentally polluting steps such as developing and etching compared to existing processes. Furthermore, the use of 3D embedding makes the molding process more precise.

[0066] In further detail, it should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A 3D printing embedded process, characterized in that: Includes the following steps, S1. Circuit design: The path of copper wires is designed and planned using software. S2. Substrate preparation: Cut the 3D printable substrate to the required dimensions to meet product specifications. S3, 3D embedded wire molding, uses 3D printing automatic embedded wire equipment to embed bare copper wires into the substrate layer by layer according to the design path to form a three-dimensional circuit, and forms a pad structure for subsequent mounting by coiling copper wires at the predetermined terminal position of the circuit. S4. Cover film (3) bonding: The cover film (3) with pre-punched pad clearance holes is bonded to the substrate surface after the wire embedding is completed. S5. High temperature pressing: High temperature pressing is carried out at a temperature of 170-180℃ to make the cover film (3) tightly bonded to the substrate and completely encapsulate the bare copper wire between the substrate and the cover film (3). S6, punching: using a steel die to punch the pressed semi-finished product into a preset shape structure; S7. Surface mount, print solder paste at the pad position, and package LED beads (5) and resistors using SMT equipment.

2. The 3D printing embedded process according to claim 1, characterized in that: It also includes S8 and post-processing, which involves drying the packaged product in a tin furnace and attaching backing adhesive (4) and gold fingers (6).

3. The 3D printing embedded process according to claim 1, characterized in that: The substrate after slitting in step S2 needs to be cleaned and dried.

4. The 3D printing embedded process according to claim 1, characterized in that: In step S3, while printing the substrate, the 3D printing wire embedding device pauses plastic printing at the layer height where the wire needs to be embedded. The bare copper wire is automatically laid into the groove reserved on the substrate through the wire embedding head of the 3D printing device. Then, the upper substrate is printed to achieve full-coverage encapsulation of the circuit.

5. The 3D printing embedded process according to claim 1, characterized in that: In S3, the solder pads are formed as follows: at the end of the buried wire path, the buried wire head is controlled to spiral or stack the wires, so that the bare copper wires form a planar spiral or raised contact structure, which serves as the carrier for subsequent solder paste printing.

6. The 3D printing embedded process according to claim 1, characterized in that: The punching and bonding of the cover film (3) in S4 specifically includes: first, punching out clearance holes on the cover film (3) with one-to-one correspondence with the position of the solder pads in step S3 using a mold, and then bonding the cover film (3) with clearance holes to the surface of the substrate using an automatic film bonding device, so that the solder pads are exposed from the clearance holes.

7. The 3D printing embedded process according to claim 1, characterized in that: The solder paste printing in S7 adopts the stencil printing method, and the solder paste is precisely coated onto the pads formed by the coiled copper wire through the clearance holes of the cover film (3).

8. The 3D printing embedded process according to claim 2, characterized in that: The step S8 of bonding the adhesive backing (4) specifically includes: first, punching the adhesive backing (4) to form clearance holes corresponding to the LED beads (5) and resistor positions, and then bonding the adhesive backing (4) to the product surface using a film bonding device.

9. The 3D printing embedded process according to claim 2, characterized in that: The step S8 of attaching the gold finger (6) specifically includes: attaching the conductive gold finger (6) to the designated area of ​​the product's assembly part, and electrically connecting the gold finger (6) to the exposed copper wire terminal.

10. An FPC backlight strip, using the 3D printing embedded process described in claims 1 to 8, characterized in that: include, 3D printable substrate layer (1); Embedded circuit (2) is composed of bare copper wires, which are completely embedded in the substrate layer (1) and form a three-dimensional trace; A solder pad is located at the end of a bare copper line and consists of a spiral-shaped protrusion formed by the coiling of copper wire. A cover film (3) layer is attached to the surface of the substrate layer (1), and a clearance hole corresponding to the position of the solder pad is provided on the cover film (3) layer; LED beads (5) and resistors are mounted on the pads using solder paste.

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