Manufacturing method of circuit board with kerfs, circuit board with kerfs and LED lamp strip

Abstract

The invention discloses a manufacturing method of a circuit board with a kerf, the circuit board with the kerf and an LED lamp strip, and the circuit board with the kerf is characterized by comprising a bottom film, an LED light source, an LED light source and an LED light source, a metal line; film jacking; the metal circuit comprises a plurality of metal circuits, the thicknesses of the plurality of metal circuits are the same or different, a plurality of straight-line-shaped or curved-line-shaped kerfs are formed on the bottom film or / and the top film in the area directly facing the circuit-free area, the shapes of the plurality of kerfs are the same or different, the top film is provided with a bonding pad window, and the bottom film or / and the top film does not rebound at the kerfs. And the glue forms a T-shaped or cross-shaped tin-resisting structure at the position of the kerf, so that tin does not permeate into a circuit beside to form a connection short circuit, and the product performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit boards, and in particular to a method for manufacturing a circuit board with a slit, a circuit board with a slit, and an LED light strip. Background Art

[0002] For a long time, when covering the film board, especially the circuit board with thick circuit, for example, the circuit board with circuit thickness greater than 35um, due to the thick circuit, the glue 5 on the two layers of film is not easy to completely fill the circuit side, so that the circuit side is covered with bubbles 5.1 (such as Figure 1 As shown in the figure), when the LED component 7 is soldered by SMT, the reflow temperature is above 200 degrees. The two layers of film on the edge of the pad are separated due to the expansion of bubbles, forming a gap. The tin 6 penetrates through the gap and contacts another line on the edge of the pad, forming a short circuit (as shown in the figure). Figure 2 As shown in the figure, especially for boards with PET film as the front film or / and the back film, due to the high elasticity of PET film, the film between two circuits is more likely to bounce up and form a gap during reflow soldering. Usually, when the circuit thickness is greater than or equal to 35um, or / and the line spacing is less than or equal to 0.7mm, or / and the film thickness is greater than or equal to 25um, gaps will be formed due to the bounce, allowing tin to pass through the gap and form a connection short circuit. The thicker the circuit, / or the larger the elastic line of the film, / or the smaller the spacing between the circuits, the more likely it is to form a gap short circuit with tin seepage.

[0003] In addition, the die-cutting method for making circuit boards has become very popular. That is, metal foil and / or metal wires are attached to a film with glue, and then the unnecessary metal is cut and removed. The existing technology cannot remove the waste materials that have formed independently. In addition, when the circuit gap of the designed circuit is too narrow and the metal foil is too thin, after the metal foil is cut, when the unnecessary waste materials are pulled up and separated from the adhesive film, the waste materials are sandwiched between the two circuits and are difficult to pull up, or cannot be pulled up at all, and break when pulled.

[0004] In order to solve this problem in the previous flexible circuit board industry, we thought of various ways, but none of them solved the problem, or after solving the problem, another problem arose. For example, the method of thickening the glue can solve the problem of the film bouncing due to bubbles when facing thick circuits. However, because the glue is too thick, it will cause excessive glue overflow when pressing the covering film, making the pad smaller, and even the overflowing glue will cover the entire metal surface of the small pad. Finally, we finally found a solution, which is to cut a layer of film or / and two layers of film into a gap between the two circuits at the location where the pad is located, so that the film will not bounce when heated. Even if it bounces, the tin will not cross the "groove" formed by the gap, and the tin will not penetrate into the adjacent circuits to form a short circuit.

[0005] Moreover, when the board is pressed, the adhesive layer is squeezed and enters the gap to form a T-shaped adhesive 5.2 structure, so that the adhesive layer forms a three-dimensional bond, and the adhesive is more firmly bonded to the two layers of film. When the circuit board is reflowed, it will not bounce open to form a gap. At the same time, the T-shaped adhesive 5.2 or the cross-shaped adhesive 5.3 has a better tin blocking effect (such as Figure 3 、 Figure 3.1 、 Figure 4 shown).

[0006] In order to solve the second problem, that is, the problem of the metal foil 2.1 being cut and the unnecessary metal foil 2.2 being pulled up and separated, but not being able to be pulled up or being broken, the base film 1 is similarly cut through on the back film opposite to the unnecessary metal foil, so that the blade is pressed against the cut metal foil 2.2 to be removed. At the same time, a micro-adhesive film 9 is attached to one side of the cut metal foil 2.1. While the blade is pushing upward, the micro-adhesive film 9 is peeled upward. Under the action of pushing and pulling, the metal foil 2.2 to be removed is smoothly adhered to the micro-adhesive film 9 and removed, and the remaining metal foil 2 forms multiple circuits of the circuit board (such as Figure 5 shown).

[0007] Therefore, it is necessary to improve and optimize the existing circuit boards. Summary of the Invention

[0008] The present invention aims to solve at least one of the problems of the prior art. To this end, the present invention provides a method for manufacturing a slitted circuit board, a slitted circuit board, and an LED light strip, which address the problems of tin seepage on circuit boards with circuit thicknesses greater than 35 μm, and the problems of unwanted metal foil being pulled off, unable to be pulled off, or breaking.

[0009] The technical solution adopted by the present invention to solve its technical problem is: In a first aspect, an embodiment of the present invention provides a method for manufacturing a circuit board with a slit, comprising: The metal foil is attached to the base film, and the unnecessary metal foil is removed by die-cutting to form a metal foil circuit; The metal wire is attached to the base film, and the wire is die-cut. A small piece is cut at multiple locations to form fragments. Then, a slitting die is used to cut through the base film and the adhesive layer with one side of the base film facing upwards. The blade is pushed upwards onto the fragments cut from the wire. At the same time, a micro-adhesive film is attached to one side of the circuit. While pushing the edge, the micro-adhesive film is lifted upwards. Under the action of pushing and sticking, the fragments are smoothly removed by the micro-adhesive film. The top film is cut out on another mold to form a solder pad window, which is then attached to the circuit layer to make a circuit board. The circuit layer of the circuit board includes a wire circuit and a metal foil circuit. There are gaps on the wires of some or all of the wire circuits. The thickness of the wire circuit is greater than that of the metal foil circuit. The adhesive-coated bottom film of the circuit board has formed multiple slits.

[0010] In a first aspect, an embodiment of the present invention further provides another method for manufacturing a circuit board with a slit, comprising: The metal foil is attached to the base film and die-cut to cut the metal foil. Then, a slitting die is used to cut through the base film with one side of the base film facing upwards, so that the blade is pressed against the metal foil that needs to be removed. At the same time, a micro-adhesive film is attached to one side of the cut metal foil. While the blade is pushing upwards, the micro-adhesive film is peeled up. Under the action of pushing and pulling, the metal foil that needs to be removed is smoothly removed by the micro-adhesive film. The remaining metal foil forms multiple circuits of the circuit board, and multiple slits are formed on the base film. The top film is cut out on another mold to form a pad window, which is then attached to the circuit layer to make a circuit board. The thickness of the multiple circuits on the circuit board is the same.

[0011] In a second aspect, an embodiment of the present invention provides a circuit board with a slit, comprising: A bottom film, a metal circuit, a top film, the metal circuit includes multiple metal circuits, the thickness of the multiple metal circuits is the same or different, the bottom film and / or the top film are formed with multiple slits in the area facing the no-circuit area, the slits are straight or curved, the shapes of the multiple slits are the same or different, and a pad window is opened on the top film.

[0012] Optionally, a layer of circuit is attached to the top film of the circuit board, and a layer of solder resist is made on the layer of circuit to form a double-layer circuit board.

[0013] Optionally, some or all of the multiple slits of the circuit board are cut in the gap between two circuits next to the pad window.

[0014] Optionally, the curved slit of the circuit board is V-shaped, C-shaped, U-shaped, square-shaped, or elliptical.

[0015] Optionally, the thicknesses of the metal circuits of the circuit board are the same or different, and the thickness of some or all of the metal circuits is ≥35 um.

[0016] Optionally, the slit of the circuit board is set at the gap between two lines, and at the slit, the line gap between the two lines is ≤0.7mm.

[0017] Optionally, the top film and bottom film of the circuit board are Pi films with glue or PET films with glue, with a total thickness of ≥25um.

[0018] Optionally, there is glue in the slit of the circuit board, and the glue forms a "T"-shaped structure or a "X"-shaped structure at the slit position of the circuit board.

[0019] In a third aspect, an embodiment of the present invention provides an LED light strip, comprising a circuit board with slits as described in any one of the embodiments of the second aspect, wherein an LED is combined on the front circuit layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional diagram of the line side with air bubble 5.1; Figure 2 This is a schematic diagram of the cross-sectional structure of an SMT soldered LED lamp 7. The two layers of film on the edge of the pad are separated due to the expansion of bubbles, forming a gap. The tin 6 penetrates through the gap and contacts another line on the edge of the pad, forming a short circuit. Figure 3 It is a cross-sectional diagram of the adhesive layer being squeezed into the gap to form the T-shaped adhesive 5.2 structure; Figure 3.1 It is a cross-sectional diagram of the structure of the cross-shaped glue 5.3 formed by the glue layer being squeezed into the gap; Figure 4 The T-shaped glue blocks the tin so that it will not seep into the adjacent circuits and form a short circuit. Schematic cross-sectional view of ; Figure 5 The micro-adhesive film is lifted upwards, and under the action of pushing on one side and sticking and pulling up on the other side, the metal foil to be removed is smoothly adhered and removed by the micro-adhesive film, and the remaining metal foil forms a three-dimensional schematic diagram of multiple circuits on the circuit board; Figure 6 This is a schematic diagram of a planar fragment formed by cutting a small piece of the conductor next to the metal foil circuit; Figure 6.1 This is a schematic diagram of a planar fragment formed by cutting a small piece of the wires on both sides of the metal foil circuit; Figure 7 This is a cross-sectional diagram of the pad where there are no cuts between the lines. Figure 8 This is a cross-sectional diagram of the bottom film after the seams are cut between the circuits at the pad; Figure 9 This is a cross-sectional diagram of the top film after cutting between the circuits at the pad; Figure 10 This is a cross-sectional diagram of the pad where both the bottom and top films are cut between the traces. Figure 11 The thickness of the conductor circuit is greater than that of the metal foil circuit, and a cross-sectional diagram of the bottom film after a seam is cut between the conductor circuit and the metal foil circuit at the pad; Figure 12 It is a planar diagram showing that the shape of the slit at the pad and the gap between the circuits is C-shaped; Figure 12.1 yes Figure 12 A partial enlarged plan view of the pad; Figure 13 It is a planar schematic diagram showing that the shape of the cut is a straight line at the pad and the gap between the circuits; Figure 13.1 yes Figure 13 A partial enlarged plan view of the pad; Figure 14 It is a planar diagram showing that the shape of the cut is U-shaped at the pad and the gap between the circuits; Figure 14.1 yes Figure 14 A partial enlarged plan view of the pad; Figure 15 It is a planar diagram showing that the shape of the cut is V-shaped at the pad and the gap between the circuits; Figure 15.1 yes Figure 15 A partial enlarged plan view of the pad; Figure 16 It is a planar diagram showing that the shape of the cut is a mouth shape at the pad and the gap between the circuits; Figure 16.1 yes Figure 16 A partial enlarged plan view of the pad; Figure 17 It is a planar schematic diagram showing that the shape of the cut is an ellipse at the pad and the gap between the circuits; Figure 17.1 yes Figure 17 A partial enlarged plan view of the pad; Figure 18 It is a planar diagram of cutting the wires on both sides of the metal foil circuit at the pad, and the gap between the wire circuit and the metal foil circuit is a C-shaped cut; Figure 18.1 yes Figure 18 A partial enlarged plan view of the pad; Description of Figure Numbers: 1-base film, 1.1-base film slit, 2-metal foil circuit, 2.1-metal foil, 2.2-unnecessary metal foil, 3-wire, 3.1-fragment, 4-top film, 4.1-top film slit, 4.2-solder pad window, 5-glue layer, 5.1-bubble, 5.2-formed T-shaped glue, 5.3-formed cross-shaped glue, 6-tin, 7-LED lamp, 8.1-C-shaped slit, 8.2-linear slit, 8.3-U-shaped slit, 8.4-V-shaped slit, 8.5-mouth-shaped slit, 8.6-elliptical slit, 9-micro-mucosal membrane. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments described below can be combined with each other in any manner unless there is any conflict.

[0022] The following provides many different embodiments or examples for realizing the structure of the present invention.

[0023] See Figure 5-Figure 11 As shown, an embodiment of the first aspect of the present invention provides a method for manufacturing a double-layer circuit board, comprising: Attach the metal foil 2.1 to the base film 1, and die-cut to remove the unnecessary metal foil 2.2 to form the metal foil circuit 2; The metal conductor 3 is attached to the bottom film 1, and the conductor 3 is die-cut, that is, the conductor 3 on the side next to the metal foil circuit 2 (such as Figure 6 、 Figure 12-17 As shown), or cutting the wires 3 on both sides of the metal foil circuit 2 ( Figure 18 、 Figure 18.1 As shown), a small piece is cut at multiple locations to form fragment 3.1 (as shown Figure 6 、 Figure 6.1 Then, use a slitting die to cut through the bottom film 1 and the adhesive layer 5 on one side of the bottom film with the knife edge facing upward, so that the knife edge is pressed upward onto the fragments 3.1 cut out of the wire. At the same time, a micro-adhesive film 9 is attached to one side of the wire. While pressing the edge, the micro-adhesive film is lifted upward. The fragments 3.1 are smoothly removed by the micro-adhesive film 9 under the action of pushing and sticking. The top film 4 is cut out on another mold to form a pad window 4.2, which is then attached to the circuit layer to form a circuit board. The circuit layer of the circuit board includes a wire circuit 3 and a metal foil circuit 2. The wire 3 of some or all of the wire circuits has a notch. The thickness of the wire circuit 3 is greater than the thickness of the metal foil circuit 2 (e.g., Figure 11 As shown in FIG), the adhesive-coated bottom film 1 of the circuit board has formed a plurality of slits 1.1 (as shown in FIG. Figure 8 shown).

[0024] The first embodiment of the present invention further provides another method for manufacturing a circuit board with slits, comprising: The metal foil 2.1 is attached to the base film 1 and the metal foil 2.1 is cut by die cutting. Then, the base film 1 is cut with one side of the base film facing upwards, and the cutting edge is pressed against the metal foil 2.2 that needs to be removed. At the same time, a micro-adhesive film is attached to one side of the cut metal foil 2.1. While the cutting edge is pushing upwards, the micro-adhesive film 9 is lifted upwards. Under the action of pushing and pulling, the metal foil 2.2 that needs to be removed is smoothly adhered to and removed by the micro-adhesive film 9. The remaining metal foil 2 forms multiple circuits of the circuit board. The base film 1 has formed multiple slits 1.1 (such as Figure 8 shown); The top film 4 is cut out on another mold to form a pad window 4.2, which is then attached to the circuit layer to produce a circuit board. The thickness of the multiple circuits 2 is the same.

[0025] A second embodiment of the present invention provides a circuit board with slits, comprising: a bottom film 1; a metal circuit 2; a top film 4; the metal circuits comprising a plurality of metal circuits 2, the plurality of metal circuits 2 having the same thickness, or the plurality of metal circuits 2 having different thicknesses, the bottom film 1 having a plurality of slits 1.1 (such as Figure 8 、 Figure 11 As shown), or / and the top film 4 is formed with a plurality of slits 4.1 in the area facing the wireless line (as shown Figure 9 、 Figure 10 As shown), the slits are linear or curved, and the shapes of the multiple slits are the same or different. A pad window 4.2 is opened on the top film 4.

[0026] See Figures 8-11 As shown, in some embodiments of the present invention, a layer of circuit is attached to the top film 4 of the circuit board, and a solder resist layer is made on this layer of circuit to form a double-layer circuit board.

[0027] The partial slit 1.1 of the bottom film 1 in the area facing the no-circuit is in the gap between the metal foil circuit 2 and the wire circuit 3 next to the pad window 4.2, or the partial slit 4.1 of the top film 4 in the area facing the no-circuit is in the gap between the metal foil circuit 2 and the wire circuit 3 next to the pad window 4.2, or the full slit 1.1 of the bottom film 1 in the area facing the no-circuit is in the gap between the metal foil circuit 2 and the wire circuit 3 next to the pad window 4.2, or the full slit 4.1 of the top film 4 in the area facing the no-circuit is in the gap between the metal foil circuit 2 and the wire circuit 3 next to the pad window 4.2.

[0028] The shape of the slit is C-shaped (such as Figure 12 、 Figure 12.1 、 Figure 18 、 Figure 18.1 As shown), or the shape of the cut is linear (as Figure 13 、 Figure 13.1 As shown), or the shape of the slit is U-shaped (as Figure 14 、 Figure 14.1 As shown), or the shape of the cut is L-shaped (as Figure 15 、 Figure 15.1 As shown), or the shape of the cut is a square (as shown Figure 16 、 Figure 16.1 as shown) or the shape of the cut is elliptical (as shown Figure 17 、 Figure 17.1 shown).

[0029] The thickness of the metal circuits 2 of the circuit board is the same or different, and the thickness of some or all of the metal circuits 2 is ≥35 μm.

[0030] The slit 1.1 of the circuit board bottom film 1 and / or the slit 4.1 of the top film 4 are set at the gap between two circuits. At the slit, the circuit gap between the two circuits is ≤0.7 mm.

[0031] The top film 4 and bottom film 1 of the circuit board are Pi films with glue or PET films with glue, with a total thickness of ≥25um.

[0032] There is glue in the slit of the circuit board, and the glue forms a "T" shape or a "X" shape at the slit position of the circuit board (such as Figure 3 、 Figures 8-11 shown).

[0033] See Figure 4 As shown, an embodiment of the third aspect of the present invention provides an LED light strip, comprising a circuit board with a slit as described in any embodiment of the second aspect above, wherein an LED lamp 7 is combined with the front circuit layer, and the LED lamp 7 can be soldered to the metal circuit 2 by soldering.

[0034] The present invention provides a circuit board with a slit, which achieves two effects at one stroke. First, the slit is cut through the base film, and the knife hits the scrap metal that needs to be removed. At the same time, the micro-sticky film sticks to the scrap and pulls it upward, so the scrap is removed very smoothly. Second, the slit formed between the circuits at the edge of the soldering pad prevents tin from seeping into a nearby circuit during soldering to form a tin short circuit. The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A method for manufacturing a circuit board with a slit, characterized in that: include: The metal foil is attached to the base film, and the unnecessary metal foil is removed by die-cutting to form a metal foil circuit; The metal wire is attached to the base film, and the wire is die-cut. A small piece is cut at multiple locations to form fragments. Then, a slitting die is used to cut through the base film and the adhesive layer with one side of the base film facing upwards. The blade is pushed upwards onto the fragments cut from the wire. At the same time, a micro-adhesive film is attached to one side of the circuit. While pushing the edge, the micro-adhesive film is lifted upwards. Under the action of pushing and sticking, the fragments are smoothly removed by the micro-adhesive film. The top film is cut out on another mold to form a solder pad window, which is then attached to the circuit layer to make a circuit board. The circuit layer of the circuit board includes a wire circuit and a metal foil circuit. There are gaps on the wires of some or all of the wire circuits. The thickness of the wire circuit is greater than that of the metal foil circuit. The adhesive-coated bottom film of the circuit board has formed multiple slits.

2. A method for manufacturing a circuit board with a slit, characterized in that: include: The metal foil is attached to the base film and die-cut to cut the metal foil. Then, a slitting die is used to cut through the base film with one side of the base film facing upwards, so that the blade is pressed against the metal foil that needs to be removed. At the same time, a micro-adhesive film is attached to one side of the cut metal foil. While the blade is pushing upwards, the micro-adhesive film is peeled up. Under the action of pushing and pulling, the metal foil that needs to be removed is smoothly removed by the micro-adhesive film. The remaining metal foil forms multiple circuits of the circuit board, and multiple slits are formed on the base film. The top film is cut out on another mold to form a pad window, which is then attached to the circuit layer to make a circuit board. The thickness of the multiple circuits on the circuit board is the same.

3. A circuit board with a slit, characterized in that: include: base film; Metal lines; apical membrane; Its characteristic is that the metal circuit includes multiple metal circuits, the thickness of the multiple metal circuits is the same or different, the bottom film and / or the top film are formed with multiple slits in the area facing the no-circuit area, the slits are straight or curved, the shapes of the multiple slits are the same or different, and a pad window is opened on the top film.

4. The circuit board with slits according to claim 3, characterized in that: The circuit board is further provided with a layer of circuit on the top film of the circuit board, and a layer of solder resist is made on the layer of circuit to form a double-layer circuit board.

5. The circuit board with slits according to claim 3, characterized in that: Part or all of the multiple slits of the circuit board are located in the gap between two circuits next to the pad window.

6. The circuit board with slits according to claim 3, characterized in that: The curved cut of the circuit board is V-shaped, C-shaped, U-shaped, square-shaped or oval-shaped.

7. The circuit board with slits according to claim 3, characterized in that: The thickness of the metal circuits of the circuit board is the same or different, and the thickness of some or all of the metal circuits is ≥35um.

8. The circuit board with slits according to claim 3, characterized in that: The slit of the circuit board is set at the gap between two circuits. At the slit, the circuit gap between the two circuits is ≤0.7mm.

9. The circuit board with slits according to claim 3, characterized in that: The top film and bottom film of the circuit board are Pi films with glue or PET films with glue, with a total thickness of ≥25um.

10. The circuit board with slits according to claim 3, characterized in that: There is glue in the cut of the circuit board, and the glue forms a "T"-shaped structure or a "X"-shaped structure at the cut position of the circuit board.

11. An LED light strip, characterized in that: A circuit board with slits comprising any one of claims 3-10, wherein the front circuit layer is combined with an LED.

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