Circuit board and manufacturing method thereof

Abstract

The invention provides a circuit board, which is provided with at least one bending area and at least one non-bending area, and comprises a first multi-layer structure, a second multi-layer structure, a third multi-layer structure, a first bonding layer, a second bonding layer and a plurality of hollow parts. The first bonding layer is arranged between the first multi-layer structure and the second multi-layer structure, and the second bonding layer is arranged between the second multi-layer structure and the third multi-layer structure. And the plurality of hollow parts are positioned in the bending area. And when the bending area is bent, the plurality of hollow parts are stressed to deform, so that the sectional area of each of the plurality of hollow parts is changed. Therefore, the problem of structural damage caused by bending deformation of the circuit board can be reduced, and the service life of the circuit board can be prolonged.

Description

Technical Field

[0001] The present application relates to a circuit board and a manufacturing method thereof, and more particularly to a circuit board and a manufacturing method thereof which can reduce protrusion deformation during bending. Background Art

[0002] The booming development of electronic products has increased the importance of display devices. In order to expand the application of display devices, flexible display devices have gradually become one of the development focuses of various manufacturers. In recent years, folding screens have been favored by mobile phone manufacturers because of their advantages such as convenient storage and large screen area, and foldable smartphones have been developed. The folding screens used in smartphones must undergo hundreds of thousands or even millions of bends, and the flexible circuit boards responsible for electrical connections must also withstand the same number of bends. Therefore, the durability of flexible circuit boards is also very important.

[0003] Please refer to Figure 8 , Figure 8 Schematic diagram of the bending of the existing flexible circuit board 900. The structure of the existing flexible circuit board 900 is a multi-layer design, and the layers are connected by adhesive layers, but no adhesive layer is provided at the bending position to retain the air gap A, thereby avoiding the problem of excessive stress when the existing flexible circuit board 900 is bent. However, when the existing flexible circuit board 900 is bent, the inner layer structure 910 is squeezed and the outer layer structure 920 is stretched. Due to the thickness of each layer, the bending radius between the layers is also different and the bending size cannot match, resulting in the inner layer structure 910 being squeezed and forming a convex deformation. The convex part is prone to friction, squeezing or collision with other components, thereby causing structural damage to the existing flexible circuit board 900.

[0004] In view of this, how to improve the bending state of the flexible circuit board to increase the life of the flexible circuit board is still a goal that relevant industries are working hard on. Summary of the invention

[0005] One embodiment of the present application provides a circuit board, which has at least one bending area and at least one non-bending area, wherein the bending area is adjacent to the non-bending area. The circuit board includes a first multilayer structure, a second multilayer structure, a third multilayer structure, a first adhesive layer, a second adhesive layer, and a plurality of hollow portions. The first multilayer structure includes a first soft material layer and a first covering film, and the first covering film is disposed on the first soft material layer. The second multilayer structure includes a second soft material layer and a second covering film, and the second covering film is disposed on the second soft material layer. The third multilayer structure includes a third soft material layer and a third covering film, and the third covering film is disposed on the third soft material layer. The first adhesive layer is disposed between the first multilayer structure and the second multilayer structure, and bonds the first soft material layer and the second covering film, wherein the first soft material layer, the first adhesive layer, and the second covering film are located between the first covering film and the second soft material layer. The second adhesive layer is disposed between the second multi-layer structure and the third multi-layer structure, and adheres the second soft material layer and the third soft material layer, wherein the second multi-layer structure is located between the first adhesive layer and the second adhesive layer, and the second soft material layer, the second adhesive layer and the third soft material layer are disposed between the second covering film and the third covering film. A first space is formed between the first multi-layer structure and the second multi-layer structure, and a second space is formed between the second multi-layer structure and the third multi-layer structure. The plurality of hollow portions are formed in at least one of the first multi-layer structure, the second multi-layer structure and the third multi-layer structure, wherein the plurality of hollow portions, the first space and the second space are all located in the bending zone, and the plurality of hollow portions are connected to at least one of the first space and the second space. When the bending zone is bent, the plurality of hollow portions are deformed by force to change the cross-sectional area of ​​each of the plurality of hollow portions.

[0006] In some embodiments, the plurality of hollow portions may be arranged in a staggered manner, and when the bending area is flattened, the planar shape of each of the plurality of hollow portions may be an ellipse, a rectangle, or a parallelogram.

[0007] In some embodiments, each of the plurality of hollow portions has a length and a width, and a ratio of the length to the width may be greater than or equal to 1.

[0008] In some embodiments, the width may be greater than or equal to 0.3 mm.

[0009] In some embodiments, there may be a shortest distance between two adjacent hollow portions, and the shortest distance may be greater than or equal to 0.3 mm.

[0010] In some embodiments, the circuit board may further include a plurality of auxiliary hollow portions formed in at least one of the first multi-layer structure, the second multi-layer structure, and the third multi-layer structure, and the plurality of auxiliary hollow portions may communicate with at least one of the first space and the second space. The plurality of auxiliary hollow portions may be located on both sides of the bending area adjacent to the non-bending area, and the plurality of auxiliary hollow portions may be separated from the plurality of hollow portions.

[0011] In some embodiments, the first soft material layer and the second soft material layer may be electrically connected in the non-bending region, and the second soft material layer and the third soft material layer may be electrically connected in the non-bending region.

[0012] Another embodiment of the present application provides a method for manufacturing a circuit board, which includes the following steps. A multilayer structure is provided, wherein the multilayer structure includes a soft material layer and a covering layer, wherein the covering layer is disposed on the soft material layer. Two gaskets are respectively attached to both sides of the multilayer structure, so that the two gaskets are respectively connected to the soft material layer and the covering layer. Two soft material sheets are respectively attached to both sides of the multilayer structure, so that the two soft material sheets are respectively connected to the soft material layer and the covering layer, and the two gaskets are respectively located between the two soft material sheets and the multilayer structure. Two covering films are respectively attached to the two soft material sheets, so that the two soft material sheets are respectively located between the two covering films and the multilayer structure. A plurality of hollow portions are provided, wherein the plurality of hollow portions are formed in at least two of the soft material layer, the covering layer, the two soft material sheets and the two covering films, and the plurality of hollow portions extend to at least one of the two gaskets. When the plurality of hollow portions are completed, the two gaskets are removed.

[0013] In some embodiments, the two soft material sheets may be adhered to the multi-layer structure by adhesive layers respectively, and the distance between the two adhesive layers and the two gaskets may be greater than or equal to 0.5 mm.

[0014] In some embodiments, before laminating the two covering films, the two soft material sheets may be electrically connected to the soft material layer respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic cross-sectional view of a circuit board according to an embodiment of the present application;

[0016] Figure 2A A partial top view of a circuit board according to an embodiment of the present application;

[0017] Figure 2B for Figure 2A A partial top view schematic diagram of a circuit board when the first covering film is stretched;

[0018] Figure 2C for Figure 2A A partial top view schematic diagram of a circuit board when the first covering film is compressed;

[0019] Figure 3 A partial top view schematic diagram of a circuit board according to another embodiment of the present application;

[0020] Figure 4 A partial top view of a circuit board according to another embodiment of the present application;

[0021] Figure 5 A schematic diagram of the bending of a circuit board according to an embodiment of the present application;

[0022] Fig. 6A A partial top view of a circuit board according to another embodiment of the present application;

[0023] Figure 6B A partial top view of a circuit board according to another embodiment of the present application;

[0024] 7A to 7F They are cross-sectional schematic diagrams of a method for manufacturing a circuit board according to an embodiment of the present application at various process stages; and

[0025] Figure 8 It is a schematic diagram of the bending of an existing flexible circuit board. DETAILED DESCRIPTION

[0026] The following application content provides many different embodiments or examples for realizing the different features of the provided subject matter. The following describes specific examples of components, values, operations, materials, configurations and the like to simplify the present application. Of course, the examples are merely examples and are not intended to be limiting. Other components, values, operations, materials, configurations and the like should also be considered. For example, in the following description, forming a first feature above a second feature may include an embodiment in which the first feature and the second feature are formed in direct contact, and may also include an embodiment in which additional features may be formed between the first feature and the second feature so that the first feature and the second feature are not in direct contact. In addition, the present application may repeat reference numerals and / or text in various examples. This repetition itself does not indicate the relationship between the various embodiments and / or configurations discussed.

[0027] In the following text, in order to clearly present the technical features of the present invention, the dimensions (such as length, width, thickness and depth) of the elements (such as layers, films, substrates and regions, etc.) in the drawings will be enlarged in unequal proportions, and the number of some elements will be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of elements in the drawings and the dimensions and shapes presented by the elements, but should cover the dimensions, shapes and deviations of the two caused by actual manufacturing steps and / or tolerances. For example, the flat surface shown in the drawings may have rough and / or nonlinear features, while the acute angles shown in the drawings may be rounded. Therefore, the elements presented in the drawings of the present invention are mainly for illustration, and are not intended to accurately depict the actual shape of the elements, nor are they used to limit the claims of the present invention.

[0028] Please refer to Figure 1 , Figure 1 Schematic diagram of a cross-section of a circuit board 100 according to an embodiment of the present application. In some embodiments of the present application, the circuit board 100 has at least one bending area 100a and at least one non-bending area 100b, wherein the bending area 100a is adjacent to the non-bending area 100b, and the circuit board 100 includes a first multi-layer structure 110, a second multi-layer structure 120, a third multi-layer structure 130, a first adhesive layer 140, a second adhesive layer 150, and a plurality of hollow portions 160.

[0029] In detail, the first multi-layer structure 110 includes a first soft material layer 111 and a first covering film 112, wherein the first covering film 112 is disposed on the first soft material layer 111. The second multi-layer structure 120 includes a second soft material layer 121 and a second covering film 122, wherein the second covering film 122 is disposed on the second soft material layer 121. The third multi-layer structure 130 includes a third soft material layer 131 and a third covering film 132, wherein the third covering film 132 is disposed on the third soft material layer 131. Although the present application takes a three-layer multi-layer structure as an example, in actual manufacturing, the number of multi-layer structures can be increased or decreased according to demand, and each multi-layer structure can have the same or similar structural design, so the present application is not limited to the number and form of multi-layer structures.

[0030] The first flexible material layer 111, the second flexible material layer 121 and the third flexible material layer 131 can each be a thin flexible copper clad laminate (FCCL), or can each include a flexible substrate (unnumbered) and a conductive layer (unnumbered). The material of the flexible substrate can be selected from the group consisting of polyester (PET), polyimide (PI), polyetherimide (PEI), polyethylenenaphthalate (PEN) and fluoropolymer, and the conductive layer can be selected from copper foil, aluminum foil, beryllium copper alloy foil or other conductive films with good flexibility. The flexible substrate and the conductive layer can be bonded by an adhesive, and the adhesive can be selected from the group consisting of polyester adhesives, acrylic adhesives, epoxy adhesives, polyimide adhesives and phenolic-butyral adhesives. Thus, wiring can be performed on the first soft material layer 111 , the second soft material layer 121 and the third soft material layer 131 , so that the conductive layers thereof form circuits to facilitate current transmission.

[0031] The materials of the first covering film 112, the second covering film 122 and the third covering film 132 can be polyester resin, polyimide resin, epoxy resin, phenolic resin, polyphenylene oxide (PPO) resin, cyanate ester (CE) resin, polytetrafluoroethylene (PTFE) resin, BT resin (bismaleimide triazine resin) or other polymer materials with insulating properties, and can be made into a film to protect the first soft material layer 111, the second soft material layer 121 and the third soft material layer 131 to prevent their conductive layers from being exposed to air and causing oxidation or damage.

[0032] The first adhesive layer 140 is disposed between the first multi-layer structure 110 and the second multi-layer structure 120, and bonds the first soft material layer 111 and the second covering film 122, so that the first soft material layer 111, the first adhesive layer 140 and the second covering film 122 are located between the first covering film 112 and the second soft material layer 121. Furthermore, the second adhesive layer 150 is disposed between the second multi-layer structure 120 and the third multi-layer structure 130, and bonds the second soft material layer 121 and the third soft material layer 131, wherein the second multi-layer structure 120 is located between the first adhesive layer 140 and the second adhesive layer 150, and the second soft material layer 121, the second adhesive layer 150 and the third soft material layer 131 are disposed between the second covering film 122 and the third covering film 132, thereby fixing the first multi-layer structure 110, the second multi-layer structure 120 and the third multi-layer structure 130.

[0033] The first adhesive layer 140 and the second adhesive layer 150 can be arranged in a local configuration so that a first space S1 is formed between the first multilayer structure 110 and the second multilayer structure 120, and a second space S2 is formed between the second multilayer structure 120 and the third multilayer structure 130. For example, the first adhesive layer 140 and the second adhesive layer 150 can be mainly arranged in the non-bending area 100b of the circuit board 100, so that the first space S1 and the second space S2 are located in the bending area 100a of the circuit board 100. When the circuit board 100 is bent, the first space S1 and the second space S2 can help release the compressive stress and tensile stress of the first multilayer structure 110, the second multilayer structure 120 and the third multilayer structure 130. It should be particularly noted that the positions of the first adhesive layer 140, the second adhesive layer 150, the first space S1 and the second space S2 can be adjusted according to the actual application situation, so the present application is not limited to the above configuration.

[0034] The plurality of hollow portions 160 are formed in at least one of the first multilayer structure 110, the second multilayer structure 120 and the third multilayer structure 130, wherein the plurality of hollow portions 160, the first space S1 and the second space S2 are all located in the bending area 100a, and the plurality of hollow portions 160 are connected to at least one of the first space S1 and the second space S2. In detail, the hollow portions 160 are preferably formed in the first multilayer structure 110 and the third multilayer structure 130 to reserve sufficient space for wiring, and taking the bending of the circuit board 100 toward the first multilayer structure 110 as an example, the hollow portions 160 can help release the compressive stress of the first multilayer structure 110 and the tensile stress of the third multilayer structure 130.

[0035] In addition, the first soft material layer 111 and the second soft material layer 121 can form an electrical connection in the non-bending area 100b, and the second soft material layer 121 and the third soft material layer 131 can form an electrical connection in the non-bending area 100b. In this way, electrical conduction can be formed between the first multi-layer structure 110, the second multi-layer structure 120 and the third multi-layer structure 130, and the position of the electrical connection is located in the non-bending area 100b, which will not be affected by the bending of the circuit board 100.

[0036] Please refer to Figure 2A , Figure 2A It is a partial top view schematic diagram of a circuit board 100 according to an embodiment of the present application. The multiple hollow portions 160 may be in a staggered honeycomb hollow structure, or may be distributed in a regular array with uniform size. When the bending area 100a is flattened, the planar shape of each of the multiple hollow portions 160 may be a rectangle. Each of the multiple hollow portions 160 has a length L and a width W, and the ratio of the length L to the width W (i.e., L / W) may be greater than or equal to 1, and the width W may be greater than or equal to 0.3 mm. There may be a shortest distance D1 between two adjacent hollow portions 160, and the shortest distance D1 may be greater than or equal to 0.3 mm. Through the above-mentioned structural configuration, the deformation and recovery ability of the circuit board 100 during bending, stretching, compression or torsion can be improved, and sufficient space can be reserved for circuit arrangement. In addition, UV laser cutting may be used to manufacture the hollow portion 160 , and the outer edge of the hollow portion 160 and the circuits disposed between the hollow portion 160 may be spaced at least 0.1 mm apart to ensure that the circuits are well covered.

[0037] Please refer to Figure 2B to Figure 2C , Figure 2B for Figure 2A A partial top view of the circuit board 100 when the first covering film 112 is stretched, Figure 2C for Figure 2A A partial top view of the circuit board 100 when the first cover film 112 is compressed. When the bending area 100a is bent, the plurality of hollow portions 160 are deformed by force to change the cross-sectional area of ​​each of the plurality of hollow portions 160, such as Figure 2B As shown, when the circuit board 100 is stretched, the cross-sectional area of ​​the hollow portion 160 is enlarged to lengthen the length of the circuit board 100, or as shown in FIG. Figure 2CAs shown, when the circuit board 100 is compressed, the cross-sectional area of ​​the hollow portion 160 is reduced to reduce the length of the circuit board 100. It should be particularly noted that when the circuit board 100 is bent or twisted, a portion of the hollow portion 160 can be expanded and another portion of the hollow portion 160 can be reduced, so that the circuit board 100 can be deformed smoothly. The hollow portion 160 can provide a movable space for the circuit board 100 when it is deformed, and other structures of the circuit board 100 have a certain elasticity and can release stress by stretching or shrinking.

[0038] Please refer to Figure 3 and Figure 4 , Figure 3 FIG. 1 is a partial top view of a circuit board 100 according to another embodiment of the present application. Figure 4 FIG. 1 is a partial top view of a circuit board 100 according to another embodiment of the present application. When the bending area 100a is flattened, the planar shape of each of the plurality of hollow portions 160 may be as follows: Figure 3 Oval, or Figure 4 Regardless of the shape of the hollow portion 160 , its distribution, length, width or the distance between adjacent hollow portions 160 can all meet the aforementioned range, so this application will not elaborate on them.

[0039] Please refer to Figure 5 , Figure 5 Schematic diagram of the bending of the circuit board 100 according to one embodiment of the present application. When the circuit board 100 is bent, one side of the circuit board 100 (here, the first multilayer structure 110 is taken as an example) is squeezed, and the other side (here, the third multilayer structure 130 is taken as an example) is stretched, so that the cross-sectional area of ​​the hollow portion 160 on the first multilayer structure 110 is reduced, and the cross-sectional area of ​​the hollow portion 160 on the third multilayer structure 130 is expanded. In this way, the bending radius of the first multilayer structure 110 is reduced and the bending radius of the third multilayer structure 130 is increased, so that the bending dimensions of the first multilayer structure 110, the second multilayer structure 120 and the third multilayer structure 130 can cooperate with each other, and no convex deformation will occur, thereby reducing the problem of structural damage of the circuit board 100 due to deformation, which helps to extend the service life of the circuit board 100.

[0040] Please refer to Fig. 6A , Fig. 6A 1 is a partial top view of a circuit board 100 according to another embodiment of the present application. The circuit board 100 may further include a plurality of auxiliary hollow portions 170 formed in at least one of the first multi-layer structure 110, the second multi-layer structure 120, and the third multi-layer structure 130, and the plurality of auxiliary hollow portions 170 may be connected to at least one of the first space S1 and the second space S2, and the setting position, structure, and size characteristics of the auxiliary hollow portions 170 may be the same or similar to those of the aforementioned hollow portions 160, and will not be described in detail herein.

[0041] The auxiliary hollow portions 170 may be located on both sides of the bending area 100a adjacent to the non-bending area 100b, and the auxiliary hollow portions 170 may be separated from the hollow portions 160. Thus, the auxiliary hollow portions 170 can also help release stress, so as to further enhance the deformation and recovery capabilities of the circuit board 100.

[0042] Please refer to Figure 6B , Figure 6B 1 is a partial top view of a circuit board 100 according to another embodiment of the present application. The plurality of hollow portions 160 may be evenly distributed in the bending zone 100a, so that the bending zone 100a is fully provided with hollow portions 160 to increase the bending ability of the circuit board 100. It can be seen from the various embodiments described above that the hollow portions 160 and the auxiliary hollow portions 170 may be formed on a single multi-layer structure or multiple multi-layer structures, and may be located at one, multiple or all areas of the bending zone 100a, and the positions of the hollow portions 160 and the auxiliary hollow portions 170 on different multi-layer structures may correspond to or be staggered to be suitable for different usage conditions, so the present application is not limited to the actual positions of the hollow portions 160 and the auxiliary hollow portions 170.

[0043] Please refer to 7A to 7F , 7A to 7F The following are cross-sectional schematic diagrams of a method for manufacturing a circuit board according to an embodiment of the present application at various process stages. Fig. 7A As shown, a multi-layer structure 210 is provided. The multi-layer structure 210 includes a soft material layer 211 and a cover layer 212. The cover layer 212 is disposed on the soft material layer 211, and the multi-layer structure 210 may be pre-disposed with an inner layer circuit.

[0044] Then, if Figure 7B As shown, two gaskets 220 are respectively attached to the two sides of the multi-layer structure 210, so that the two gaskets 220 are respectively connected to the soft material layer 211 and the covering layer 212. The gasket 220 can have a gasket material layer 221 and a gasket adhesive layer 222. When attaching the gasket 220, the gasket adhesive layer 222 can be facing the multi-layer structure 210, and pressure is applied to make the gasket 220 bonded to the multi-layer structure 210. The material of the gasket material layer 221 can be polyester or polyimide, and its thickness can be 5μm to 25μm. The material of the gasket adhesive layer 222 can be a thermoplastic polymer, such as a thermoplastic acrylic polymer, and its thickness can be 5μm to 15μm. The bonding force between the gasket adhesive layer 222 and the multi-layer structure 210 can be less than or equal to 200mN / 25mm to ensure that the gasket 220 can be peeled off smoothly without residual glue later.

[0045] Then, if Figure 7CAs shown, two soft material sheets 230 are respectively attached to the two sides of the multi-layer structure 210, so that the two soft material sheets 230 are respectively connected to the soft material layer 211 and the cover layer 212, and the two gaskets 220 are respectively located between the two soft material sheets 230 and the multi-layer structure 210. The two soft material sheets 230 can be attached to the multi-layer structure 210 by adhesive layers 240, and the distance D2 between the two adhesive layers 240 and the two gaskets 220 can be greater than or equal to 0.5 mm to prevent the adhesive layers 240 and the gaskets 220 from sticking to each other.

[0046] Then, if Fig.7D As shown, before the subsequent steps, the two soft material sheets 230 can be electrically connected to the soft material layer 211. In this step, the soft material sheet 230 can also be etched and selectively copper plated to construct a suitable circuit between the soft material sheet 230 and the composite structure 210.

[0047] Then, if Fig. 7E As shown, two covering films 250 are respectively attached to the two soft material sheets 230, so that the two soft material sheets 230 are respectively located between the two covering films 250 and the multi-layer structure 210. The covering films 250 and the aforementioned covering layer 212 can be combined with the soft material sheets 230 or the soft material layer 211 by lamination to protect the circuits on the soft material sheets 230 and the soft material layer 211.

[0048] Then, if Figure 7F As shown, a plurality of hollow portions 260 are provided, and the plurality of hollow portions 260 are formed in at least two of the soft material layer 211, the cover layer 212, the two soft material sheets 230 and the two cover films 250, and the plurality of hollow portions 260 extend to at least one of the two gaskets 220. After the plurality of hollow portions 260 are provided, the gasket 220 can be peeled off from both sides to remove the two gaskets 220.

[0049] The hollow portion 260 can be cut to a fixed depth using a UV laser, and the edge of the hollow portion 260 can be more than 0.1 mm away from the circuit. During cutting, the soft material sheet 230 and the covering film 250 on the same side can be cut through, but the gasket 220 is not cut through, so as to form a hollow portion 260 located on a single side. Alternatively, the hollow portion 260 can be cut out in advance on the multi-layer structure 210. By selectively configuring the hollow portion 260 on the multi-layer structure 210, the soft material sheet 230 and the covering film 250, the diversity of the configuration of the hollow portion 260 can be increased.

[0050] In summary, the circuit board of the present application can help release the compressive stress and tensile stress when bending the circuit board by forming a honeycomb-shaped hollow portion, so that the bending dimensions between different multi-layer structures can cooperate with each other without causing convex deformation, thereby reducing the problem of structural damage to the circuit board due to bending deformation, and helping to extend the service life of the circuit board.

[0051] Although the present application has been disclosed as above with reference to the embodiments, it is not intended to limit the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be determined by the following claims.

[0052]

Explanation of symbols

[0053] 100: Circuit board

[0054] 100a: bending area

[0055] 100b: non-bending area

[0056] 110: First composite structure

[0057] 111: first soft material layer

[0058] 112: first covering film

[0059] 120: Second composite structure

[0060] 121: second soft material layer

[0061] 122: Second covering film

[0062] 130: The third composite structure

[0063] 131: third soft material layer

[0064] 132: Third covering film

[0065] 140: first adhesive layer

[0066] 150: Second adhesive layer

[0067] 160,260: hollow part

[0068] 170: Auxiliary hollowing part

[0069] 210:Multi-layer structure

[0070] 211: Soft material layer

[0071] 212: Covering layer

[0072] 220: Gasket

[0073] 221: Gasket material layer

[0074] 222: Gasket adhesive layer

[0075] 230: Soft material sheet

[0076] 240: Adhesive layer

[0077] 250: Covering film

[0078] S1: First Space

[0079] S2: Second Space

[0080] L: Length

[0081] W: Width

[0082] D1: Shortest distance

[0083] D2: Distance.

Claims

1. A circuit board having at least one bending area and at least one non-bending area, wherein the bending area is adjacent to the non-bending area, characterized in that: The circuit board comprises: The first multi-layer structure comprises: a first soft material layer; and a first covering film, disposed on the first soft material layer; The second multi-layer structure comprises: a second soft material layer; and a second covering film, disposed on the second soft material layer; The third multi-layer structure comprises: A third soft material layer; and a third covering film, disposed on the third soft material layer; a first adhesive layer, disposed between the first multi-layer structure and the second multi-layer structure, and bonding the first soft material layer and the second covering film, wherein the first soft material layer, the first adhesive layer and the second covering film are located between the first covering film and the second soft material layer; a second adhesive layer, disposed between the second multi-layer structure and the third multi-layer structure, and bonding the second soft material layer and the third soft material layer, wherein the second multi-layer structure is located between the first adhesive layer and the second adhesive layer, and the second soft material layer, the second adhesive layer and the third soft material layer are disposed between the second covering film and the third covering film; wherein a first space is formed between the first multi-layer structure and the second multi-layer structure, and a second space is formed between the second multi-layer structure and the third multi-layer structure; and A plurality of hollow portions are formed in at least one of the first multi-layer structure, the second multi-layer structure, and the third multi-layer structure, wherein the plurality of hollow portions, the first space, and the second space are all located in the bending area, and the plurality of hollow portions are connected to at least one of the first space and the second space; When the bending area is bent, the plurality of hollow portions are deformed by force to change the cross-sectional area of ​​each of the plurality of hollow portions.

2. The circuit board according to claim 1, characterized in that The plurality of hollow portions are arranged in a staggered manner, and when the bending area is flattened, the planar shape of each of the plurality of hollow portions is an ellipse, a rectangle or a parallelogram.

3. The circuit board according to claim 1, characterized in that: Each of the plurality of hollow portions has a length and a width, and a ratio of the length to the width is greater than or equal to 1.

4. The circuit board according to claim 3, characterized in that: The width is greater than or equal to 0.3 mm.

5. The circuit board according to claim 1, wherein: There is a shortest distance between two adjacent hollow portions, and the shortest distance is greater than or equal to 0.3 mm.

6. The circuit board according to claim 1, wherein: Also includes: A plurality of auxiliary hollow portions are formed in at least one of the first multi-layer structure, the second multi-layer structure and the third multi-layer structure, and the plurality of auxiliary hollow portions are connected to at least one of the first space and the second space; The plurality of auxiliary hollow portions are located at two sides of the bending area adjacent to the non-bending area, and the plurality of auxiliary hollow portions are separated from the plurality of hollow portions.

7. The circuit board according to claim 1, characterized in that: The first soft material layer and the second soft material layer are electrically connected in the non-bending area, and the second soft material layer and the third soft material layer are electrically connected in the non-bending area.

8. A method for manufacturing a circuit board, characterized in that: Include: A multi-layer structure is provided, the multi-layer structure comprising: soft material layer; and A covering layer, disposed on the soft material layer; Laminating two gaskets to two sides of the multi-layer structure respectively, so that the two gaskets connect the soft material layer and the covering layer respectively; Laminating two soft material sheets to two sides of the multi-layer structure respectively, so that the two soft material sheets respectively connect the soft material layer and the covering layer, and the two gaskets are respectively located between the two soft material sheets and the multi-layer structure; Laminating two covering films onto the two soft material sheets respectively, so that the two soft material sheets are respectively located between the two covering films and the multi-layer structure; A plurality of hollow portions are provided, wherein the plurality of hollow portions are formed in at least two of the soft material layer, the covering layer, the two soft material sheets and the two covering films, and the plurality of hollow portions extend to at least one of the two gaskets; as well as When the plurality of hollow portions are arranged, the two gaskets are removed.

9. The method for manufacturing a circuit board according to claim 8, wherein: The two soft material sheets are respectively adhered to the multi-layer structure by adhesive layers, and the distance between the two adhesive layers and the two gaskets is greater than or equal to 0.5 mm.

10. The method for manufacturing a circuit board according to claim 8, wherein: Before laminating the two covering films, the two soft material sheets are electrically connected to the soft material layer respectively.

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