Flexible circuit board and intelligent watchband

Abstract

The utility model provides a flexible circuit board and an intelligent watchband. The flexible circuit board comprises a conductive layer containing metal, a coating, a bonding layer containing thermosensitive glue and an insulating layer. The coating can be subjected to complexation reaction with the metal of the conductive layer; the conductive layer, the coating and the bonding layer are sequentially stacked on the insulating layer, and the problem that the binding force of thermosensitive glue to metal is low is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic products, in particular to a flexible circuit board and an intelligent watch band. Background Art

[0002] With the continuous development of the electronics industry, the design of electronic products, from appearance to internal structure, tends to be more delicate, light and small. Therefore, the processes involved in the manufacturing process of products are complex. Especially for the stacking and assembly process of wearable sensitive electronic materials, higher requirements are needed, and it is necessary to optimize and reduce the manufacturing process as much as possible to reduce the risk of damage to the FPC during the manufacturing process.

[0003] In wearable electronic products, the watch band is used with a high bending frequency, and high requirements are imposed on the bonding force after the assembly of the electronic material FPC soft board in the watch band. Therefore, a thermal sensitive adhesive needs to be used for FPC hot pressing bonding. The FPC is composed of a variety of different material layers stacked and bonded. Since the thermal sensitive adhesive has no bonding force on the metal SUS area on the FPC, it is necessary to find a way to improve the bonding force of the FPC metal area. Summary of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a flexible circuit board, aiming to solve the problem of low bonding force of the thermal sensitive adhesive to the metal.

[0005] The utility model provides a flexible circuit board, which includes a conductive layer containing metal, a coating, a bonding layer containing a thermal sensitive adhesive, and an insulating layer; the coating can undergo a complexation reaction with the metal of the conductive layer; the conductive layer, the coating, and the bonding layer are sequentially stacked on the insulating layer.

[0006] In one embodiment, the conductive layer includes a plurality of metal regions and at least one first flexible region, and two adjacent metal regions are connected by one first flexible region to make the conductive layer bendable.

[0007] In one embodiment, the bonding layer includes a plurality of thermal sensitive adhesive regions and at least one second flexible region, and two adjacent thermal sensitive adhesive regions are connected by one second flexible region to make the bonding layer bendable.

[0008] In one embodiment, a plurality of the thermal sensitive adhesive regions and the metal regions are stacked in one-to-one correspondence, and the coating is arranged between the thermal sensitive adhesive regions and the metal regions, and the first flexible regions and the second flexible regions are bonded in one-to-one correspondence.

[0009] In one embodiment, the material of the second flexible region is textile fabric.

[0010] In one embodiment, the material of the first flexible region is textile fabric.

[0011] In one embodiment, the coating is a primer containing thermoplastic acrylic acid.

[0012] In one embodiment, the coating is a primer containing polyurethane-modified acrylic resin.

[0013] In one embodiment, the material of the insulating layer is plastic.

[0014] The present utility model also provides an intelligent watch band, which includes a protective cover and the flexible circuit board as described above, and the protective cover wraps around the outside of the flexible circuit board.

[0015] For the flexible circuit board provided by the present utility model, by attaching a coating that can undergo a complexation reaction with metal on the conductive layer containing metal, a new chemical bond is formed between the coating and the metal, firmly attaching to the conductive layer. Then, the insulating layer is bonded to the conductive layer through the adhesive layer containing thermosensitive adhesive, improving the adhesiveness between the adhesive layer and the conductive layer containing metal, thereby enhancing the bonding stability between the conductive layer and the insulating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is an exploded structural schematic diagram of the flexible circuit board in the first embodiment of the present utility model.

[0018] Reference numerals: 10, conductive layer; 11, metal area; 12, first flexible area; 20, coating; 30, adhesive layer; 31, thermosensitive adhesive area; 32, second flexible area; 40, insulating layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will describe in detail specific embodiments of the present utility model with reference to the drawings. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the description of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

[0020] In the description of the present utility model, unless otherwise clearly defined and limited, terms such as "arrangement", "installation", "connection", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0021] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the catheter of this utility model is customarily placed during use. It is only for the convenience of description and simplification of the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model.

[0022] Terms such as "first", "second", "third", etc. are only used to distinguish elements with similar attributes, rather than indicating or implying relative importance or a specific order.

[0023] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion. In addition to including the listed elements, it may also include other elements not specifically listed.

[0024] The first embodiment

[0025] Please refer to Figure 1 , an embodiment of one aspect of the present utility model provides a flexible circuit board, including a conductive layer 10, a coating layer 20, an adhesive layer 30, and an insulating layer 40. The conductive layer 10 contains metal; the coating layer 20 can undergo a complexation reaction with the metal of the conductive layer 10; the adhesive layer 30 contains a thermosensitive adhesive; the conductive layer 10, the coating layer 20, and the adhesive layer 30 are sequentially stacked on the insulating layer 40.

[0026] Specifically, the conductive function of the conductive layer 10 is mainly exerted by the metal. The metal is usually etched into the shapes of wires, electrodes, etc. required by the design through special chemical corrosion and etching processes, and constitutes the basic path of the circuit, enabling current to flow on the circuit board, thereby realizing the connection between electronic components and the transmission of signals. The insulating layer 40 forms the basic layer of the circuit. The adhesive layer 30 bonds the metal to the insulating layer 40. The insulating layer 40 can not only be used as a protective covering to isolate the circuit from dust and moisture, but also provides environmental protection and electronic insulation functions. The insulating layer 40 not only provides the basic support and protection of the circuit, but also ensures the safe and reliable operation of the circuit through its excellent electrical insulation performance and mechanical strength.

[0027] The metal is also surface-treated by complexation reaction with the coating 20 to form new chemical bonds or active groups, increasing the affinity of the metal surface for the thermosensitive adhesive, helping to improve the adhesion between the thermosensitive adhesive and the metal. Secondly, it can also adjust the surface energy of the metal surface, making the interfacial energy between the metal and the thermosensitive adhesive better match, thereby promoting the interaction and adhesion between the two and ensuring the stability and reliability of the circuit. The design and manufacturing process of the conductive layer 10 are crucial for the overall performance and reliability of the FPC, directly affecting the functionality and service life of electronic products.

[0028] Selecting a thermosensitive adhesive with low-temperature reaction can protect the electronic components on the FPC flexible board. In this embodiment, the thermosensitive adhesive is further selected as the Tesa 58480 thermosensitive adhesive. This thermosensitive adhesive is a low-temperature reaction thermosensitive adhesive, suitable for electronic materials, plastics, anodized aluminum, and has extremely high adhesion performance and reliability, even in thin bonding areas and thin design gaps. In addition, the thermosensitive adhesive also has characteristics such as activation at low temperature and low pressure, excellent shock resistance, anti-sebum, extremely low percolation rate, adhesion to anodized aluminum, adhesion to plastics, and the ability to install sensitive electronic components.

[0029] In this embodiment, the conductive layer 10 includes a plurality of metal regions 11 and at least one first flexible region 12. Two adjacent metal regions 11 are connected by a first flexible region 12 to make the conductive layer 10 bendable.

[0030] Specifically, the metal region 11 can specifically be a copper foil, and its thickness is preferably 0.009 mm - 0.072 mm. The first flexible region 12 can be made of a flexible material or have the flexibility to be folded or bent by being movably connected to the metal region 11. The way of this movable connection can be further set as a hinge connection.

[0031] In this embodiment, the bonding layer 30 includes a plurality of thermosensitive adhesive regions 31 and at least one second flexible region 32. Two adjacent thermosensitive adhesive regions 31 are connected by a second flexible region 32 to make the bonding layer 30 bendable.

[0032] Specifically, the thermosensitive adhesive region 31 is mainly formed by the thermosensitive adhesive, and a certain amount of thermosensitive adhesive can also be attached to the second flexible region 32 for pasting with other components. Of course, in the case of no special requirements, other forms of fasteners or other types of adhesives can also be attached to the second flexible region 32.

[0033] In this embodiment, a plurality of thermosensitive adhesive regions 31 and metal regions 11 are stacked in one-to-one correspondence, and the coating 20 is provided between the thermosensitive adhesive regions 31 and the metal regions 11, and the first flexible region 12 and the second flexible region 32 are adhesively bonded in one-to-one correspondence.

[0034] Specifically, multiple thermosensitive adhesive regions 31 and multiple metal regions 11 can be bonded and laminated through the coating 20. At this time, the number of coatings 20 is equivalent to the number of thermosensitive adhesive regions 31 or metal regions 11, making the bonding between the entire conductive layer 10 and the bonding layer 30 relatively stable. It can also be that some of the thermosensitive adhesive regions 31 and metal regions 11 are bonded through the coating 20, and the other parts are bonded by other methods. The other methods include adding surface treatment agents in the thermosensitive adhesive regions 31, using special adhesives, sandblasting or frosting the surfaces of the metal regions 11, etc. After testing, the bonding strength between the metal region 11 and the thermosensitive adhesive region 31 through the coating 20 can reach 90 N, while the bonding strength when the metal region 11 and the thermosensitive adhesive region 31 are directly bonded is only 3 N. It can be seen that this embodiment has made substantial progress.

[0035] In this embodiment, the material of the second flexible region 32 is a textile fabric.

[0036] In this embodiment, the material of the first flexible region 12 is a textile fabric.

[0037] Specifically, using textile fabrics as the materials for the first flexible region 12 and the second flexible region 32 can improve the bonding strength. After testing, the bonding strength between the first flexible region 12 and the second flexible region 32 through the thermosensitive adhesive can reach 90 N.

[0038] In this embodiment, the coating 20 is a primer containing thermoplastic acrylic or polyurethane-modified acrylic resin.

[0039] Specifically, thermoplastic acrylic and polyurethane-modified acrylic resins have good covering power and durability. Their chemical adhesion mechanism is to form a paint film through a chemical reaction with the metal substrate. This paint film can adhere tightly to the metal surface and is used for the bonding layer 30 to bond.

[0040] At a more specific level, the chemical reaction of thermoplastic acrylic and polyurethane-modified acrylic resins may include reacting with the active metal atoms on the surface of the metal substrate to form a complex structure. This structure is attached to the metal surface through chemical bonds, providing excellent adhesion. This adhesion not only enhances the durability of the paint film.

[0041] In this embodiment, the material of the insulating layer 40 is plastic.

[0042] Specifically, the plastic material is further selected as polyimide or polyester material. These materials have good electrical insulation performance and mechanical strength, and can protect the circuit from interference and damage from the external environment.

[0043] In this embodiment, it further includes a reinforcing layer (not shown in the figure). The reinforcing layer is provided on the side of the insulating layer 40 away from the conductive layer 10.

[0044] Specifically, in the flexible circuit, a rigid member formed of aluminum or stainless steel can be adopted to provide stability, further providing physical support for the placement of components and wires, as well as stress release. The rigid member and the flexible circuit can be bonded together through a thermosetting adhesive, ensuring the stability and reliability of the circuit.

[0045] Furthermore, the reinforcing layer is provided corresponding to the metal area 11 to avoid affecting the foldability of the flexible circuit board.

[0046] The bonding process of the flexible circuit board in this embodiment is as follows:

[0047] S1, Coat the coating 20 on the metal area 11;

[0048] S2, Preheat the thermosetting adhesive onto the metal area 11 and the first flexible area 12 to form a bonding layer 30;

[0049] S3, Thermally press to activate the thermosetting adhesive, so that the insulating layer 40 and the conductive layer 10 are bonded together through the bonding layer 30;

[0050] S4, Cold press.

[0051] The flexible circuit board provided in this embodiment attaches a coating 20 that can undergo a complexation reaction with the metal on the conductive layer 10 containing the metal, so that the coating 20 and the metal form a new chemical bond and firmly adhere to the conductive layer 10. Then, the insulating layer 40 is bonded to the conductive layer 10 through the bonding layer 30 containing the thermosetting adhesive, improving the adhesion between the bonding layer 30 and the conductive layer 10 containing the metal, thereby enhancing the bonding stability between the conductive layer 10 and the insulating layer 40.

[0052] Second Embodiment

[0053] Another implementation manner of the present invention provides a smart watchband, including a protective cover and the flexible circuit board as described in the first embodiment, and the protective cover wraps around the flexible circuit board.

[0054] Specifically, the protective cover can be made of materials and shapes such as leather covers and nylon material covers, which are relatively soft and have strong ornamental properties, for further protecting the flexible circuit board and improving the aesthetic effect.

[0055] As described above, the above are only specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A flexible circuit board, characterized in that, Comprising: A conductive layer (10) containing metal; A coating (20) capable of undergoing a complexation reaction with the metal of the conductive layer (10); An adhesive layer (30) containing a thermosensitive adhesive; An insulating layer (40), with the conductive layer (10), the coating (20), and the adhesive layer (30) sequentially stacked on the insulating layer (40).

2. The flexible circuit board according to claim 1, wherein The conductive layer (10) includes a plurality of metal regions (11) and at least one first flexible region (12), and two adjacent metal regions (11) are connected by one first flexible region (12) to enable the conductive layer (10) to be bendable.

3. The flexible circuit board according to claim 2, wherein, The adhesive layer (30) includes a plurality of thermosensitive adhesive regions (31) and at least one second flexible region (32), and two adjacent thermosensitive adhesive regions (31) are connected by one second flexible region (32) to enable the adhesive layer (30) to be bendable.

4. The flexible circuit board according to claim 3, wherein, A plurality of the thermosensitive adhesive regions (31) are stacked in one-to-one correspondence with the metal regions (11), and the coating (20) is disposed between the thermosensitive adhesive regions (31) and the metal regions (11), and the first flexible regions (12) and the second flexible regions (32) are adhesively bonded in one-to-one correspondence.

5. The flexible circuit board according to claim 3, wherein The material of the second flexible region (32) is a textile fabric.

6. The flexible circuit board according to claim 2, characterized in that, The material of the first flexible region (12) is a textile fabric.

7. The flexible circuit board according to claim 1, wherein, The coating (20) is a primer containing thermoplastic acrylic acid.

8. The flexible circuit board according to claim 1, wherein The coating (20) is a primer containing polyurethane-modified acrylic resin.

9. The flexible circuit board according to claim 1, characterized in that, The material of the insulating layer (40) is plastic.

10. An intelligent watchband, characterized in that, Including a protective cover and a flexible circuit board according to any one of claims 1-9, with the protective cover wrapping around the flexible circuit board.

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