Circuit board, transparent display screen and manufacturing method thereof

Abstract

The application discloses a circuit board, a transparent display screen and a manufacturing method thereof, and relates to the technical field of circuit boards, in particular to a circuit board, a transparent display screen and a manufacturing method thereof. The circuit board comprises a light-transmitting film, a circuit layer and glue, and further comprises a cover film. The circuit layer is combined on one side of the light-transmitting film through the glue, the circuit layer comprises multiple groups of circuit units, and there is a space between two adjacent groups of circuit units to form a vacancy. The cover film is combined on the light-transmitting film and the circuit layer, and a pad window is arranged on the cover film or the light-transmitting film to expose the circuit layer to form a pad. The cover film is disconnected at the vacancy position, so that the cover films on the two adjacent groups of circuit units are discontinuous. Alternatively, the circuit board comprises the light-transmitting film, the circuit layer and the glue, and does not comprise the cover film. The circuit layer is combined on one side of the light-transmitting film through the glue. The light-transmitting film is provided with the glue at positions with the circuit and is not provided with the glue at all or part of positions without the circuit. The circuit board is a bare circuit board, or the circuit layer is provided with a solder resist ink. The light transmittance of the transparent display screen is improved, and the manufacturing cost of the transparent display screen is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of transparent display technology, specifically to circuit boards, transparent display screens, and their manufacturing methods. Background Technology

[0002] There are two types of existing flexible printed circuit boards (FPCBs): one is a three-layer structure consisting of a PI or PET film layer, an adhesive layer, and a circuit layer, with the circuit layer bonded to the film by the adhesive layer, and the film layer itself covered with adhesive; the other is a PI or PET film layer and a circuit layer, with the circuit layer directly bonded to the film layer, and the film layer completely free of adhesive. The former type, with adhesive, incurs high costs due to the adhesive covering the entire film, even in areas without circuitry. The latter, with adhesive-free FPCBs, also faces significant challenges in manufacturing due to the high technical difficulty and equipment investment required, resulting in high costs and low adoption rates in the industry.

[0003] Transparent displays remain transparent or semi-transparent in areas without metal wiring or LED chips, whether illuminated or not. When applied to glass, they do not completely block light, but only partially, creating a significant market demand.

[0004] Transparent flexible displays are made by soldering LED beads onto transparent flexible circuit boards. The transparent flexible boards are made of light-transmitting film, adhesive, and metal foil and / or metal wire. Since metal blocks light, the light transmittance of the transparent circuit board is determined by the percentage of the area occupied by the metal. The smaller the area occupied by the metal, the greater the light transmittance. The areas without metal blocking the light are the light-transmitting areas. There are also transparency requirements for the light-transmitting areas, which depend on the film and adhesive materials. The film material is generally PET film, which has high transparency and can withstand low-temperature soldering of 200 degrees Celsius. It is also resistant to yellowing during use. The adhesive, on the other hand, needs to meet the requirements of transparency, resistance to soldering temperature of 200 degrees Celsius, and resistance to yellowing. Adhesives that meet these requirements are very expensive, making the cost of adhesives used on transparent flexible boards very high. This results in a high production cost for transparent flexible displays, hindering their widespread adoption and popularization.

[0005] Therefore, it is necessary to improve and optimize existing transparent displays. Summary of the Invention

[0006] The present invention aims to solve at least one of the problems of the prior art. To this end, the present invention provides a circuit board, a transparent display screen, and a method for manufacturing the same, which improves the light transmittance of the transparent display screen and significantly reduces the manufacturing cost of the transparent display screen.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] In a first aspect, embodiments of the present invention provide a method for manufacturing a circuit board, comprising:

[0009] A. Prepare two rolls of adhesive-coated light-transmitting film, wherein the adhesive on the light-transmitting film is continuous or spaced, and the adhesive on the light-transmitting film is light-transmitting or opaque; attach metal foil to the surface of the light-transmitting film to obtain two rolls of coated metal sheets;

[0010] B. Using the die-cutting method, the metal-clad laminate is fabricated on a multi-station die-cutting machine to obtain two rolls of bare circuit boards.

[0011] C. Prepare a roll of adhesive cover film, use die-cutting to make pad windows on the cover film to form a cover film with pad windows, and cut the cover film with pad windows into multiple strips to form multiple adhesive film strips.

[0012] D. After the cover film is cut, the film strips with odd-numbered positions are attached to one roll of bare circuit board, and the film strips with even-numbered positions are attached to the other roll of bare circuit board, resulting in two rolls of circuit board.

[0013] In a first aspect, embodiments of the present invention also provide another method for manufacturing a circuit board, including:

[0014] A. Prepare two rolls of transparent film with adhesive, wherein the adhesive on the transparent film is continuous or spaced, and the adhesive on the transparent film is transparent or opaque; use a die-cutting method to make pad windows on the transparent film to form two rolls of transparent film with pad windows.

[0015] B. Adhere metal foil to the light-transmitting film with solder pad windows to obtain two rolls of covered metal plates. Use the die-cutting method on a multi-station die-cutting machine to make circuits on the covered metal plates to obtain two rolls of bare circuit boards.

[0016] C. Prepare a roll of adhesive-coated cover film, and cut the cover film into multiple strips on the multi-station die-cutting machine to form multiple adhesive-coated film strips;

[0017] D. After the cover film is cut, the film strips with odd-numbered positions are attached to one roll of bare circuit board, and the film strips with even-numbered positions are attached to the other roll of bare circuit board, resulting in two rolls of circuit board.

[0018] In a first aspect, embodiments of the present invention provide another method for manufacturing a circuit board, comprising:

[0019] A. Prepare a roll of light-transmitting film with adhesive. The adhesive on the light-transmitting film can be light-transmitting or opaque. The adhesive on the light-transmitting film is in strips, and there are multiple strips. There are gaps between adjacent strips of adhesive. The strips of adhesive are not continuous, or they are continuous in some parts.

[0020] B. Adhere the metal foil to the strip adhesive, and use die-cutting, etching or laser engraving to make the circuit on the strip adhesive, so that the strip adhesive has the circuit, and obtain a bare circuit board. The light-transmitting film has no adhesive in all or part of the areas where there is no circuit.

[0021] C. A solder resist layer is formed on the surface of the circuit, wherein the solder resist layer is solder resist ink; or, no solder resist layer is formed on the surface of the circuit, and the bare circuit board can be used directly.

[0022] Optionally, in step A, adhesive is printed on the translucent film. Specifically, according to the circuit design, a screen printing stencil or gravure template for printing adhesive is designed, and the adhesive is printed on the translucent film using a screen printing machine or gravure printing machine to form a circuit shape.

[0023] In step B, after drying the solvent, the metal foil is bonded to the adhesive; etch-resistant line ink is printed, with the line ink corresponding to the adhesive position; after etching, the etch-resistant ink is removed to form the line; or, the metal foil is die-cut using a die-cutting machine, the unwanted metal foil is torn off, and the remaining metal foil forms the line, with no adhesive on all or part of the areas on the light-transmitting film where there is no line.

[0024] Optionally, the metal foil is copper foil, copper-aluminum composite foil, or aluminum foil.

[0025] Optionally, the material of the light-transmitting film is a light-transmitting PET film.

[0026] Optionally, the circuit board obtained by the method described in any of the first aspects above is a circuit board with a length greater than 2 meters. Multiple connecting circuit boards can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards. The distance between two adjacent connecting circuit boards is m, where m ≥ 10 cm.

[0027] Secondly, embodiments of the present invention provide a method for manufacturing a transparent display screen, comprising:

[0028] E. On the circuit board with connecting circuit board obtained by the above manufacturing method, solder paste is printed. Solder paste can be printed on the connecting circuit board at the same time. LED beads with built-in control chip and light-emitting chip are SMT packaged and reflow soldered to form a long roll of flexible display semi-finished product. The connecting circuit board and the circuit board form a solder connection.

[0029] F. On the flexible display screen semi-finished product, cut to the required length at the cutting positions every multiple rows of LED beads, or cut to the required length at the position of the connecting circuit board to make a transparent display screen, wherein the connecting circuit board is used to connect the controller and / or power supply.

[0030] Thirdly, embodiments of the present invention provide a circuit board, including a light-transmitting film, a circuit layer, and an adhesive, and also including a cover film; the circuit layer is bonded to one side of the light-transmitting film by adhesive, the circuit layer includes multiple sets of circuit units, and adjacent sets of circuit units are spaced apart to form gaps; the cover film is bonded to the light-transmitting film and the circuit layer, and the cover film or the light-transmitting film is provided with pad windows to expose the circuit layer to form pads, and the cover film is broken at the gap positions, so that the cover film on adjacent sets of circuit units is discontinuous;

[0031] Alternatively, it may include a light-transmitting film, a circuit layer, and adhesive, but exclude a cover film; the circuit layer is bonded to one side of the light-transmitting film by adhesive, and the light-transmitting film has adhesive in the locations where there are circuits, and no adhesive in all or part of the locations where there are no circuits; the circuit board is a bare circuit board, or the circuit layer is provided with solder resist ink.

[0032] Optionally, the cover film is provided, and adhesive is present at some positions in the vacancy, the adhesive in the vacancy being discontinuous or partially continuous, and the adhesive being a light-transmitting adhesive or an opaque adhesive; or, the cover film is provided, and adhesive is present at all positions in the vacancy, and the adhesive is a light-transmitting adhesive; or, the cover film is not provided, and the adhesive is a light-transmitting adhesive or an opaque adhesive.

[0033] Optionally, the light-transmitting film is a light-transmitting PET film.

[0034] Optionally, the other side of the light-transmitting film has no circuit layer; or, the other side of the light-transmitting film has a circuit layer, with the circuit layers on the front and back sides of the light-transmitting film facing each other and forming a connection.

[0035] Optionally, the circuit layer disposed on the other side of the light-transmitting film contains positive and negative main circuits.

[0036] Optionally, the circuit board is a circuit board with a length greater than 2 meters. Multiple connecting circuit boards can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards. The distance between two adjacent connecting circuit boards is m, where m ≥ 10 cm.

[0037] Optionally, the line width of the circuit layer is greater than, equal to, or less than the width of the adhesive bonded to the circuit.

[0038] Optionally, it includes solder resist ink, the solder resist ink and the circuit overlap, the width of the solder resist ink is relative to the width of the circuit to which the ink is bonded, and the ink width is greater than, equal to or less than the circuit width.

[0039] Fourthly, embodiments of the present invention provide a transparent display screen, including a circuit board as described in any of the embodiments of the third aspect above, wherein LED beads are soldered on at least some of the pads, and connecting wires or connecting circuit boards are soldered to one or both ends of the display screen, wherein the connecting wires or connecting circuit boards are used to connect to a controller and / or a power supply; or, the display screen has no connecting wires or connecting circuit boards, and the circuit board is provided with connecting pads, which are used to connect to a controller and / or a power supply.

[0040] Optionally, the display screen has a light-emitting surface, and a light-transmitting adhesive is disposed on the light-emitting surface.

[0041] The present invention has at least one of the following beneficial effects: In the embodiments of the present invention, for double-layer film circuit boards, the cover film is interrupted at the empty positions between two adjacent sets of circuit units, making the cover film on the two adjacent sets of circuit units discontinuous. The pad windows are set on the light-transmitting film or the cover film, which abandons the structure of the prior art in which both films are continuous light-transmitting films, reduces and saves the amount of cover film used, improves the light transmittance of the display screen, and also reduces the weight of the display screen; in addition, for the structure of discontinuous or partially continuous adhesive in the empty positions, the amount of adhesive used is reduced and saved, further improving the light transmittance of the display screen and further reducing the weight of the display screen.

[0042] In this embodiment of the invention, for single-layer film circuit boards, adhesive is present on the light-transmitting film at the locations where there are circuits, and no adhesive is present at all or part of the locations where there are no circuits; the circuit board is a bare circuit board, or solder resist ink is provided on the circuit layer, which abandons the structure of continuous full-surface adhesive in the prior art, reduces and saves the amount of adhesive used, improves the light transmittance of the display screen, and also reduces the weight of the display screen. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the planar structure of the adhesive on the light-transmitting film in an embodiment of the present invention, where the adhesive is spaced apart.

[0044] Figure 2 yes Figure 1 Cross-sectional view of the structure shown;

[0045] Figure 3 This is a schematic diagram of a planar structure in an embodiment of the invention where the adhesive on the light-transmitting film is a continuous, full-surface adhesive.

[0046] Figure 4 yes Figure 3 Cross-sectional view of the structure shown;

[0047] Figure 5 This is a schematic diagram of the planar structure of three sets of circuit units combined on the light-transmitting film in an embodiment of the present invention (the adhesive on the light-transmitting film is spaced adhesive, and the circuit units are disconnected and not connected).

[0048] Figure 6 yes Figure 5 The diagram shows a planar structure when the cover film is incorporated (the cover film is broken at the empty position, making the cover film on two adjacent sets of line units discontinuous).

[0049] Figure 7 yes Figure 6 The diagram shows the planar structure of the display screen after the LED beads have been soldered.

[0050] Figure 8 yes Figure 6 A schematic diagram of the cross-sectional structure of AA;

[0051] Figure 9 This is a schematic diagram of the cross-sectional structure of the display circuit board when all positions in the empty space are filled with adhesive in an embodiment of the present invention (the cover film is broken at the empty position, so that the cover film on the two adjacent groups of circuit units is discontinuous, and the pad window is set on the cover film).

[0052] Figure 10 This is a cross-sectional view of the display circuit board in an embodiment of the present invention when the cover film is broken at the empty position and the cover film on two adjacent sets of circuit units is discontinuous (there is glue in some positions in the empty position, the glue in the empty position is discontinuous, and the solder pad window is set on the light-transmitting film).

[0053] Figure 11 This is a cross-sectional view of the display circuit board in an embodiment of the present invention when the cover film is broken at the empty position and the cover film on two adjacent sets of circuit units is discontinuous (all positions in the empty position are filled with glue, and the solder pad window is set on the light-transmitting film).

[0054] Figure 12 This is a cross-sectional structural diagram of a single-layer film display circuit board in an embodiment of the present invention (some positions in the vacancy have adhesive, the adhesive in the vacancy is discontinuous, and there is no solder resist ink).

[0055] Figure 13 This is a cross-sectional structural diagram of a single-layer film display circuit board in an embodiment of the present invention (some positions in the vacancy have adhesive, the adhesive in the vacancy is discontinuous, and there is solder resist ink).

[0056] Figure 14 yes Figure 13 The diagram shows a structure with positive and negative main circuits on the back side.

[0057] Figure 15 This is a schematic diagram of a planar structure of an embodiment of the present invention in which an adhesive with the same shape as the circuit is printed on a light-transmitting film.

[0058] Figure 16 yes Figure 15 The diagram shows a planar structure of a bare circuit board with circuits fabricated on a transparent film with adhesive (the shape of the circuits matches the shape of the adhesive).

[0059] Figure 17 This is a schematic diagram of a planar structure in an embodiment of the present invention, in which a connecting circuit board is provided at the upper end of the circuit board (the connecting circuit board connects three circuit units);

[0060] Figure 18 This is a schematic diagram of a planar structure in an embodiment of the present invention, in which the upper and lower ends of the circuit board are provided with connecting circuit boards (the connecting circuit boards connect three circuit units);

[0061] Figure 19 yes Figure 18 The diagram shows the planar structure of the display screen when LED beads are soldered onto the structure shown.

[0062] Figure 20 yes Figure 18 A partial cross-sectional view of the overlapping section of the connecting circuit boards;

[0063] Figure 21 yes Figure 19 A cross-sectional view of the overlapping section of the connecting circuit boards (partial view, the connecting circuit boards are connected by solder).

[0064] Figure 22 This is a schematic diagram of the planar structure of the adhesive first and second parts printed on the light-transmitting film in an embodiment of the present invention.

[0065] Figure 23 yes Figure 22 The diagram shows a bare circuit board planar structure when the circuit is fabricated (it has 5 circuit units, and the 5 circuit units are connected).

[0066] Figure 24 yes Figure 23 The diagram shows a schematic of the circuit board structure after solder resist ink has been applied (a connecting pad is provided at the bottom).

[0067] Figures 25-27 These are schematic diagrams of three cross-sectional structures of the line width and adhesive width in embodiments of the present invention;

[0068] Figure 28 This is a structural diagram of two circuit boards being spliced ​​together to form a longer board;

[0069] Figures 29-31 These are schematic diagrams of three cross-sectional structures of line width and ink width in embodiments of the present invention;

[0070] Explanation of icon numbers:

[0071] 1-Transparent film, 2-Adhesive, 3-Covering film, 4-Pad window, 5-LED lamp bead, 6-Solder resist ink, 7-Main circuit, 8-Connecting circuit board, 9-Tin, 10-Circuit unit, 11-Circuit layer, c-Empty space, e-Connecting pad. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described below can be arbitrarily combined with each other.

[0073] The following provides many different implementation methods or examples for implementing the structure of the present invention.

[0074] See Figures 1-28 The first aspect of this invention provides a method for manufacturing a circuit board, comprising:

[0075] A. Prepare two rolls of light-transmitting film 1 with adhesive 2, wherein the adhesive 2 on the light-transmitting film 1 is continuous; or, see Figure 1 and Figure 2 As shown, the adhesive 2 on the light-transmitting film 1 is a spaced-out light-transmitting adhesive, which eliminates the need for some adhesive, saves on adhesive usage, and also helps improve the light transmittance of the circuit board. Metal foil, specifically copper foil, copper-aluminum composite foil, or aluminum foil, is adhered to the surface of the light-transmitting film 1 to obtain two rolls of metal sheets. The adhesive on the light-transmitting film 1 includes three cases: ① The entire surface of the side of the light-transmitting film 1 used to bond the metal foil is covered with adhesive 2; therefore, the adhesive 2 on the light-transmitting film 1 is a continuous, full-surface adhesive, in which case the adhesive is a light-transmitting adhesive (fully transparent or semi-transparent); ② The side of the light-transmitting film 1 used to bond the metal foil has several spaced-out adhesives, such as... Figure 1 As shown, the adhesives are spaced apart and not continuous. In this case, adhesive 2 can be a translucent adhesive or an opaque adhesive; ③, the translucent film 1 is an adhesive with several gaps on one side used to bond the metal foil, and the adhesives are spaced apart as follows: Figure 1 As shown, there are gaps, but there are thin adhesive strips (not shown in the drawing) in the gaps to connect the adhesives that are spaced apart, so that the adhesives form a continuous adhesive. At this time, adhesive 2 can be a light-transmitting adhesive or an opaque adhesive.

[0076] B. Using the die-cutting method, the metal-clad laminate is used on a multi-station die-cutting machine to fabricate the circuit board, resulting in two rolls of bare circuit boards. The bare circuit boards are as follows: Figure 5 As shown, the bare circuit board has 3 groups of circuit units 10. In actual products, the number of circuit units can be more.

[0077] C. Prepare a roll of adhesive cover film 3. Cover film 3 can be a light-transmitting PET film or an opaque film. The adhesive on cover film 3 is a full-surface adhesive. Use the die-cutting method to make pad windows on cover film 3 to form a cover film with pad windows. Cut the cover film with pad windows into multiple strips to form multiple strips of adhesive film.

[0078] D. After slicing the cover film 3, attach the film strips at odd-numbered positions to one roll of bare circuit board, and attach the film strips at even-numbered positions to the other roll of bare circuit board, resulting in two rolls of circuit boards. Specifically, attach the film strips at positions 1, 3, 5… to one roll of bare circuit board from step B, and attach the film strips at positions 2, 4, 6… to the other roll of bare circuit board from step B, resulting in two rolls of circuit boards. Figure 6 As shown; in the prior art, the cover film 3 is not slit, but is directly bonded to a roll of bare circuit board. Figure 8 In the present invention, position 'a' on the circuit board has no cover film, whereas in existing circuit boards, position 'a' has a cover film. Clearly, compared to the prior art, this application breaks the cover film 3 at the gap 'c' between two adjacent sets of circuit units 10, making the cover film 3 discontinuous on the adjacent sets of circuit units 10. This saves on the amount of cover film used, improves the light transmittance of the display screen, and reduces the weight of the display screen. For position 'a', when the adhesive on the selected light-transmitting film is continuous, position 'a' has no cover film, while some or all of the position has adhesive, such as... Figure 9 As shown; when the adhesive on the selected light-transmitting film is a spaced-out light-transmitting adhesive, position a has no covering film and no light-transmitting adhesive, as shown. Figure 8 As shown. The method described in this embodiment also has the following advantages: the die-cutting method for circuit board processing has a high degree of automation, high efficiency, low cost, and is more environmentally friendly (existing display boards are made by etching); the production of display circuit boards in whole rolls is highly efficient, and then the length can be cut as needed by the user; each cut display circuit board is not spliced ​​from multiple segments (existing technology is spliced ​​from multiple segments, the seams are prone to breakage, and water can seep in from the back at the seams).

[0079] The first aspect of the present invention also provides a second method for manufacturing a circuit board, comprising:

[0080] A. Prepare two rolls of transparent film with adhesive, wherein the adhesive on the transparent film is continuous; or, the adhesive on the transparent film is spaced-out transparent adhesive; use a die-cutting method to create pad windows on the transparent film to form two rolls of transparent film with pad windows; the adhesive on the transparent film also includes three cases, as described in the first circuit board manufacturing method above.

[0081] B. Adhere metal foil, specifically copper foil, copper-aluminum composite foil, or aluminum foil, onto the light-transmitting film with solder pad windows to obtain two rolls of covered metal plates. Use a die-cutting method on a multi-station die-cutting machine to fabricate circuits on the covered metal plates, resulting in two rolls of bare circuit boards.

[0082] C. Prepare a roll of adhesive-coated cover film, and cut the cover film into multiple strips on the multi-station die-cutting machine to form multiple adhesive-coated film strips;

[0083] D. After slicing the cover film, attach the film strips at odd-numbered positions to one roll of bare circuit board, and the film strips at even-numbered positions to the other roll of bare circuit board, resulting in two rolls of circuit boards. Specifically, attach the film strips at positions 1, 3, 5… to one roll of bare circuit board from step B, and the film strips at positions 2, 4, 6… to the other roll of bare circuit board from step B, resulting in two rolls of circuit boards. Figure 10 or Figure 11 As shown; in the prior art, the cover film is not cut, but directly bonded to a roll of bare circuit board. Figure 10 In this paper, position b on the circuit board has no cover film, whereas in existing circuit boards, position b has a cover film. Clearly, compared to existing technologies, this application breaks the cover film at the gap between adjacent sets of circuit units 10, making the cover film 3 discontinuous on adjacent sets of circuit units 10. This saves on the amount of cover film used, improves the light transmittance of the display screen, and reduces the weight of the display screen. For position b, when the adhesive on the selected light-transmitting film is continuous, position b has no cover film, but some or all of the position has adhesive, such as... Figure 11 As shown; when the adhesive on the selected translucent film is a spaced adhesive, position b has no covering film and no translucent adhesive, as shown. Figure 10 As shown. The method described in this embodiment also has the following advantages: the die-cutting method for circuit board processing has a high degree of automation, high efficiency, low cost, and is more environmentally friendly (existing display boards are made by etching); the production of display circuit boards in whole rolls is highly efficient, and then the length can be cut as needed by the user; each cut display circuit board is not spliced ​​from multiple segments (existing technology is spliced ​​from multiple segments, the seams are prone to breakage, and water can seep in from the back at the seams).

[0084] The first aspect of the present invention also provides a third method for manufacturing a circuit board, comprising:

[0085] A. Prepare a roll of adhesive-coated translucent film. The adhesive on the film can be translucent or opaque. The adhesive on the film is in strips, and there are multiple strips. There are gaps between adjacent strips, including discontinuous breaks between adjacent strips. The structure of the adhesive-coated translucent film 1 can be as follows: Figure 1 and Figure 2 As shown; this also includes strips of adhesive that are continuous despite having gaps between them, such as... Figure 22 As shown.

[0086] B. Select copper foil, copper-aluminum composite foil, or aluminum foil and adhere it to the strip adhesive. Use die-cutting, etching, or laser engraving methods to create circuitry on the strip adhesive, resulting in a bare circuit board. The transparent film should be free of adhesive where there are no circuitry areas. Figure 23 As shown; or, the translucent film has no adhesive in some areas without wiring, and adhesive in others, such as... Figure 12 As shown.

[0087] C. Form a solder resist layer on the surface of the circuit. The solder resist layer is solder resist ink. See details. Figure 13 As shown; or, no solder mask layer is applied to the surface of the circuit, and the bare circuit board can be used directly, see details. Figure 12 As shown. From Figure 12 and Figure 13 It can be seen that the adhesive between the two sets of circuit units 10 is discontinuous, or from... Figure 23 It can be seen that the glue positions between the two sets of circuit units 10 are continuous, which reduces the use of glue, helps to improve the light transmittance of the circuit board, reduce costs, and reduce weight.

[0088] In the above three embodiments, the material of the light-transmitting film is a light-transmitting PET film.

[0089] In the third circuit board manufacturing method described above, this embodiment of the invention provides a more detailed manufacturing method, specifically: In step A, adhesive is printed on the translucent film. Specifically, according to the circuit design, a screen printing stencil or gravure template for printing the adhesive is designed, and the adhesive is printed on the translucent film using a screen printing machine or a gravure printing machine to form the circuit shape. See details [link to documentation]. Figure 15 or Figure 22 As shown; in step B, after drying the solvent, the metal foil is bonded to the adhesive; etch-resistant circuit ink is printed, with the circuit ink corresponding to the adhesive position; after etching, the etch-resistant ink is removed to form the circuit, as shown. Figure 16 or Figure 23 As shown; or, use a die-cutting machine to cut the metal foil, tear off the unwanted metal foil, and retain the metal foil to form the circuit, such as... Figure 16 As shown. The resulting circuit board has no adhesive in all areas of the transparent film where there are no circuits; depending on the printing of the adhesive, it can also have no adhesive in some areas of the transparent film where there are no circuits, and adhesive in some areas.

[0090] In the above method embodiment, the circuit board is manufactured to a length greater than 2 meters. Multiple connecting circuit boards 8 can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards 8. The distance between two adjacent connecting circuit boards is m, where m ≥ 10 cm. By connecting the circuit boards 8, the circuit boards can be spliced ​​together to form a longer circuit board for use, such as... Figure 28As shown. A second aspect of the present invention provides a method for manufacturing a transparent display screen, comprising:

[0091] E. On the circuit board obtained by the manufacturing method described in the above embodiment with connecting circuit boards, solder paste is printed. Solder paste can be printed simultaneously on the connecting circuit board. LED beads containing control chips and light-emitting chips are SMT-packaged. Reflow soldering is performed to form a long roll of flexible display screen semi-finished product. The connecting circuit boards are soldered together to form electrical connections. See details... Figure 21 As shown, the two are connected by tin 9.

[0092] F. On the flexible display screen semi-finished product, cut to the required length at the cutting positions of every multiple rows of LED beads, or cut to the required length at the position of the connecting circuit board to make a transparent display screen, wherein the connecting circuit board is used to connect the controller and / or power supply.

[0093] A third aspect of the present invention provides a circuit board, comprising:

[0094] Transparent film 1, which is a transparent PET film;

[0095] The circuit layer 11 is bonded to one side of the light-transmitting film 1 by adhesive 2. The circuit layer includes multiple sets of circuit units 10, with gaps c between adjacent sets of circuit units 10. See details. Figure 8 , Figure 10 or Figure 12 , Figure 16 , Figure 23 As shown;

[0096] See details Figure 8 or Figure 9 As shown in Embodiment 1, it also includes a cover film 3, which can be a light-transmitting PET film. The cover film 3 is bonded to the light-transmitting film 1 and the circuit layer 11, specifically by adhesive bonding. The cover film 3 has pad windows 4 to expose the circuit layer 11 to form pads. The cover film 3 is broken at the empty position c, so that the cover film 3 on the two adjacent sets of circuit units 10 is discontinuous. Thus, in the empty position c between the two adjacent sets of circuit units 10, because the cover film 3 is discontinuous, some positions in the empty position c do not have the cover film 3, that is, the use of part of the cover film 3 is saved, which obviously reduces the cost and weight. And because some positions in the empty position c do not have the cover film 3, compared with the prior art where the corresponding position has the cover film 3, the light transmittance of the display circuit board is obviously improved (because even if the cover film 3 is a light-transmitting film, although it can transmit light, the light transmittance cannot be 100%).

[0097] See details Figure 10 or Figure 11As shown, Embodiment 2 further includes a cover film 3, which is bonded to the light-transmitting film 1 and the circuit layer 11. The light-transmitting film 1 has pad windows 4 to expose the circuit 11 to form pads. The cover film 3 is broken at the empty position c, so that the cover film 3 on the two adjacent sets of circuit units 10 is discontinuous. Thus, in the empty position c between the two adjacent sets of circuit units 10, because the cover film 3 is discontinuous, some positions in the empty position c do not have the cover film 3, that is, the use of part of the cover film 3 is saved, which obviously reduces the cost and weight. And because some positions in the empty position c do not have the cover film 3, compared with the prior art where the corresponding position has the cover film 3, the light transmittance of the display circuit board is obviously improved (because even if the cover film 3 is a light-transmitting film, although it can transmit light, the light transmittance cannot be 100%).

[0098] The third aspect of the present invention also provides a third type of circuit board, embodiment 3: the circuit board does not have a cover film, the circuit layer 11 is bonded to one side of the light-transmitting film 1 by adhesive 2, the light-transmitting film 1 has adhesive 2 on the locations where there are circuits, and no adhesive on all locations where there are no circuits (e.g. Figure 16 (as shown), or some areas are without adhesive (such as...) Figure 12 As shown or Figure 13 The circuit board is a bare circuit board (e.g.) Figure 12 (as shown), or solder resist ink (such as) is applied to the circuit layer. Figure 13 (As shown).

[0099] See details Figure 8 or Figure 10 As shown, the circuit board has a cover film 3. In some embodiments, some positions in the vacancy c are filled with adhesive. The adhesive in the vacancy is discontinuous or partially continuous. In this case, the adhesive can be a light-transmitting adhesive or an opaque adhesive. This structure not only reduces and saves the use of the cover film 3, but also reduces and saves the use of adhesive, further reducing the manufacturing cost of the circuit board and further improving the light transmittance of the circuit board. See details below. Figure 9 or Figure 11 As shown, in some other embodiments, the covering film 3 is provided, and all positions in the vacancy are filled with adhesive; in this case, the adhesive is a light-transmitting adhesive; see details below. Figure 12 or Figure 13 As shown, in some other embodiments, there is no covering film 3, in which case the adhesive can be a light-transmitting adhesive or an opaque adhesive.

[0100] In some embodiments of the present invention, the other side of the light-transmitting film 1 has no circuit layer, and the circuit board is a single-layer circuit board. Specifically, see [link to relevant documentation]. Figure 8 or Figure 9 or Figure 12 or Figure 13 As shown, the front side of the light-transmitting film 1 has a circuit layer 11, while the back side has no circuit layer; see details below. Figure 10or Figure 11 As shown, the back of the light-transmitting film has a circuit layer 11, while the front has no circuit layer; in other embodiments, see details below. Figure 14 As shown, a circuit layer is provided on the other side of the light-transmitting film 1. The circuit layers on the front and back sides of the light-transmitting film 1 are arranged facing each other and form a connection, that is, the circuit board is a double-layer circuit board.

[0101] See Figure 14 As shown, in some embodiments of the present invention, the circuit layer disposed on the other side of the light-transmitting film 1 contains positive and negative main circuits 7. The arrangement of the positive and negative main circuits 7 enables the circuit board to have a larger current load.

[0102] See details Figure 18 , 28 As shown, the circuit board is a circuit board with a length greater than 2 meters. Multiple connecting circuit boards 8 can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards 8. The distance between two adjacent connecting circuit boards 8 is m, where m ≥ 10 cm.

[0103] For details regarding the line width and adhesive width, please refer to [link / reference]. Figures 25-27 As shown, the line width of the circuit layer is greater than, equal to, or less than the width of the adhesive bonded to the circuit.

[0104] See details Figures 29-31 The invention includes solder resist ink 6, which overlaps with the circuit. The width of the solder resist ink 6 is relative to the width of the circuit to which the ink is bonded, and the ink width is greater than, equal to, or less than the circuit width.

[0105] See details Figure 7 As shown, this embodiment of the invention also provides a transparent display screen, including a circuit board as described in any of the above embodiments, with LED beads 5 soldered on at least some of the pads, and connecting wires or connecting circuit boards (such as...) soldered to one or both ends of the display screen. Figure 18 As shown), the connecting wires or connecting circuit board 8 are used to connect the controller and / or the power supply. In other embodiments, the display screen may not have connecting wires and connecting circuit boards; instead, the circuit board may have connecting pads e (such as...). Figure 24 As shown), the connection pads are used to connect the controller and / or power supply.

[0106] In some embodiments of the present invention, the display screen has a light-emitting surface, and a light-transmitting adhesive is disposed on the light-emitting surface.

[0107] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that, include: A. Prepare two rolls of adhesive-coated light-transmitting film, wherein the adhesive on the light-transmitting film is continuous or spaced, and the adhesive on the light-transmitting film is light-transmitting or opaque; attach metal foil to the surface of the light-transmitting film to obtain two rolls of coated metal sheets; B. Using the die-cutting method, the metal-clad laminate is fabricated on a multi-station die-cutting machine to obtain two rolls of bare circuit boards. C. Prepare a roll of adhesive cover film, use die-cutting to make pad windows on the cover film to form a cover film with pad windows, and cut the cover film with pad windows into multiple strips to form multiple adhesive film strips. D. After the cover film is cut, the film strips with odd-numbered positions are attached to one roll of bare circuit board, and the film strips with even-numbered positions are attached to the other roll of bare circuit board, to obtain two rolls of circuit board.

2. A method for manufacturing a circuit board, characterized in that, include: A. Prepare two rolls of transparent film with adhesive, wherein the adhesive on the transparent film is continuous or spaced, and the adhesive on the transparent film is transparent or opaque; use a die-cutting method to make pad windows on the transparent film to form two rolls of transparent film with pad windows. B. Adhere metal foil to the light-transmitting film with solder pad windows to obtain two rolls of covered metal plates. Use the die-cutting method on a multi-station die-cutting machine to make circuits on the covered metal plates to obtain two rolls of bare circuit boards. C. Prepare a roll of adhesive-coated cover film, and cut the cover film into multiple strips on the multi-station die-cutting machine to form multiple adhesive-coated film strips; D. After the cover film is cut, the film strips with odd-numbered positions are attached to one roll of bare circuit board, and the film strips with even-numbered positions are attached to the other roll of bare circuit board, resulting in two rolls of circuit board.

3. A method for manufacturing a circuit board, characterized in that, include: A. Prepare a roll of light-transmitting film with adhesive. The adhesive on the light-transmitting film can be light-transmitting or opaque. The adhesive on the light-transmitting film is in strips, and there are multiple strips. There are gaps between adjacent strips of adhesive. The strips of adhesive are not continuous, or they are continuous in some parts. B. Adhere the metal foil to the strip adhesive, and use die-cutting, etching or laser engraving to make the circuit on the strip adhesive, so that the strip adhesive has the circuit, and obtain a bare circuit board. The light-transmitting film has no adhesive in all or part of the areas where there is no circuit. C. A solder resist layer is formed on the surface of the circuit, wherein the solder resist layer is solder resist ink; or, no solder resist layer is formed on the surface of the circuit, and the bare circuit board can be used directly.

4. A method for manufacturing a circuit board according to claim 3, characterized in that: In step A, adhesive is printed on the translucent film. Specifically, according to the circuit design, a screen printing stencil or gravure template for printing adhesive is designed, and the adhesive is printed on the translucent film using a screen printing machine or gravure printing machine to form the circuit shape. In step B, after drying the solvent, the metal foil is bonded to the adhesive; The ink used for printing etch-resistant circuits corresponds to the adhesive positions. After etching, the etch-resistant ink is removed to form the circuit. Alternatively, a die-cutting machine can be used to cut the metal foil, and the unwanted metal foil can be peeled off. The remaining metal foil forms the circuit, and the light-transmitting film is free of adhesive in all or part of the areas where there are no circuits.

5. A method for manufacturing a circuit board according to any one of claims 1-4, characterized in that: The metal foil is copper foil, copper-aluminum composite foil, or aluminum foil.

6. A method for manufacturing a circuit board according to any one of claims 1-4, characterized in that: The translucent film is made of translucent PET film.

7. A method for manufacturing a circuit board according to any one of claims 1-4, characterized in that: The circuit board obtained by the method described in any one of claims 1-4 is a circuit board with a length greater than 2 meters. Multiple connecting circuit boards can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards. The distance between two adjacent connecting circuit boards is m, where m ≥ 10 cm.

8. A method for manufacturing a transparent display screen, characterized in that, include: E. On the circuit board obtained by the manufacturing method of claim 7 above, solder paste is printed, and the solder paste can be printed on the connecting circuit board at the same time. LED beads with built-in control chip and light-emitting chip are SMT encapsulated, and reflow soldered to form a long roll of flexible display semi-finished product. The connecting circuit board and the circuit board form a solder connection. F. On the flexible display screen semi-finished product, cut to the required length at the cutting positions every multiple rows of LED beads, or cut to the required length at the position of the connecting circuit board to make a transparent display screen, wherein the connecting circuit board is used to connect the controller and / or power supply.

9. A circuit board, characterized in that: The device includes a light-transmitting film, a circuit layer, and an adhesive, as well as a cover film. The circuit layer is bonded to one side of the light-transmitting film by the adhesive. The circuit layer includes multiple sets of circuit units, with gaps between adjacent sets of circuit units to form empty spaces. The cover film is bonded to the light-transmitting film and the circuit layer. The cover film or the light-transmitting film has pad windows to expose the circuit layer and form pads. The cover film is interrupted at the empty spaces, so that the cover film on adjacent sets of circuit units is discontinuous. Alternatively, it may include a light-transmitting film, a circuit layer, and adhesive, but exclude a cover film; the circuit layer is bonded to one side of the light-transmitting film by adhesive, and the light-transmitting film has adhesive in the locations where there are circuits, and no adhesive in all or part of the locations where there are no circuits; the circuit board is a bare circuit board, or the circuit layer is provided with solder resist ink.

10. A circuit board according to claim 9, characterized in that: The device has the covering film, with adhesive in some of the vacant spaces, the adhesive in the vacant spaces being discontinuous or partially continuous, and the adhesive being a light-transmitting adhesive or an opaque adhesive; or, it has the covering film, with adhesive in all of the vacant spaces, and the adhesive being a light-transmitting adhesive; or, it does not have the covering film, and the adhesive is a light-transmitting adhesive or an opaque adhesive.

11. A circuit board according to claim 9, characterized in that: The light-transmitting film is a light-transmitting PET film.

12. A circuit board according to any one of claims 9-11, characterized in that: The other side of the light-transmitting film has no circuit layer; or, the other side of the light-transmitting film has a circuit layer, with the circuit layers on the front and back sides of the light-transmitting film facing each other and forming a connection.

13. A circuit board according to claim 12, characterized in that: The circuit layer on the other side of the light-transmitting film contains positive and negative main circuits.

14. A circuit board according to claim 9, characterized in that: The circuit board is a circuit board with a length greater than 2 meters. Multiple connecting circuit boards can be glued onto the circuit board to obtain a circuit board with multiple connecting circuit boards. The distance between two adjacent connecting circuit boards is m, where m ≥ 10 cm.

15. A circuit board according to claim 9, characterized in that: The width of the circuit layer is greater than, equal to, or less than the width of the adhesive bonded to the circuit.

16. A circuit board according to claim 9, characterized in that: It has solder resist ink, the solder resist ink and the circuit overlap, the width of the solder resist ink is relative to the width of the circuit to which the ink is bonded, and the ink width is greater than, equal to or less than the circuit width.

17. A transparent display screen, characterized in that: The circuit board includes any one of claims 9-16, wherein LED beads are soldered on at least some of the pads, and connecting lines or connecting circuit boards are soldered to one or both ends of the display screen, wherein the connecting lines or connecting circuit boards are used to connect to the controller and / or the power supply; or, the display screen has no connecting lines or connecting circuit boards, and the circuit board is provided with connecting pads, which are used to connect to the controller and / or the power supply.

18. A transparent display screen according to claim 17, characterized in that: The display screen has a light-emitting surface, and a light-transmitting adhesive is disposed on the light-emitting surface.

Images