CN106879159A - Flexible circuit board with 3D structure, manufacturing method thereof, and electronic device - Google Patents

Abstract

A flexible circuit board with a 3D structure, which includes a first surface and a second surface opposite to the first surface, the first surface has at least one first protrusion, and the at least one first protrusion is along the The first surface protrudes, the second surface has at least one first concave portion, and the at least one first concave portion is concave along the second surface, and each first convex portion is correspondingly arranged on the first concave portion. Concave-convex structures are formed on the opposite first surface and second surface of the flexible circuit board with 3D structure. In addition, the present invention also provides a method for manufacturing the above-mentioned flexible circuit board with 3D structure, and an electronic device using the above-mentioned flexible circuit board with 3D structure.

Description

Flexible circuit board with 3D structure, manufacturing method thereof, and electronic device

technical field

The invention relates to a flexible circuit board with a 3D structure, a manufacturing method thereof, and an electronic device using the flexible circuit board with a 3D structure.

Background technique

In recent years, thin, light and small electronic products have been favored by consumers. The internal space of electronic products is getting smaller and smaller, which makes the internal mechanism design of electronic products more and more complicated. It is bound to require flexible circuit boards (FPC) to be closely attached to the internal mechanisms of electronic products to save space. At present, the flat FPC is usually folded into a 3D structure to match the FPC with the internal space structure of the device on which it is installed. In the device, however, this method requires the use of adhesive tape, which increases the cost, increases the thickness of the product to a certain extent and reduces the heat resistance of the electronic product, and after a period of use, as the adhesive tape decreases, the 3D structure The FPC is easy to rebound and deform or even break away from the mechanism.

Contents of the invention

In view of this, it is necessary to provide a new flexible circuit board with 3D structure to solve the above problems.

In addition, it is also necessary to provide a method for manufacturing the flexible circuit board with the above-mentioned 3D structure.

In addition, it is also necessary to provide an electronic device using the flexible circuit board with the above-mentioned 3D structure.

A flexible circuit board with a 3D structure, which includes a first surface and a second surface opposite to the first surface, the first surface has at least one first protrusion, and the at least one first protrusion is along the The first surface protrudes, the second surface has at least one first concave portion, and the at least one first concave portion is concave along the second surface, and each first convex portion is correspondingly arranged on the first concave portion. Concave-convex structures are formed on the opposite first surface and second surface of the flexible circuit board with 3D structure.

A method for manufacturing a flexible circuit board with a 3D structure, comprising the steps of:

Step S1: providing a flat flexible circuit board;

Step S2: Provide a forming mold with heating and cooling functions. The forming mold has an upper mold and a lower mold matching the upper mold. The upper mold and the lower mold of the forming mold cooperate to form a mold cavity. The upper mold has a The first molding surface, the lower mold has a second molding surface, the first molding surface has at least one second concave portion, the second concave portion is concave along the first molding surface, and the second molding surface has at least one The second protruding portion protrudes along the second molding surface. When the upper mold and the lower mold are combined, each second concave portion faces a second protruding portion. The upper mold is the airbag structure;

Step S3: placing the flat flexible circuit board in the mold cavity, heating the flat flexible circuit board to the deformation temperature of the flat flexible circuit board, and heating the flat flexible circuit board compression molding, to obtain an intermediate;

Step S4: cooling the intermediate to produce a flexible circuit board with a 3D structure.

An electronic device using the flexible circuit board with a 3D structure, the shape of the flexible circuit board with a 3D structure matches the spatial structure of the flexible circuit board for installing the 3D structure in the electronic device.

The surface of the flexible circuit board with 3D structure has a concave-convex structure, and the concave-convex structure has strong rigidity, thereby improving the rigidity of the flexible circuit board with 3D structure. In addition, the shape of the flexible circuit board of the 3D structure matches the spatial structure of the flexible circuit board of the electronic device for installing the 3D structure, so that the flexible circuit board of the 3D structure can be directly arranged on the electronic device for In terms of the space structure of the flexible circuit board with 3D structure, the use of adhesive tape is avoided, which is beneficial to saving the internal space of the electronic device and reducing the thickness of the electronic device.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a flexible circuit board with a 3D structure according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a flexible circuit board with a 3D structure according to yet another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a flexible circuit board with a 3D structure according to another embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a flat flexible circuit board.

Fig. 5 is a schematic diagram of an intermediate body obtained by thermoforming a flat flexible circuit board with a molding die.

Description of main component symbols

3D Structured Flexible Circuit Board 100, 100a, 100b first surface 11 first protrusion 111 second surface 12 first depression 121 concave-convex structure 13 flat flexible circuit board 200 Forming mold 300 upper mold 301 first molding surface 3011 second depression 3012 Lower mold 302 Second molding surface 3021 second protrusion 3022 Cavity 310 intermediate 400

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

detailed description

Please refer to FIGS. 1-3, a flexible circuit board 100 with a 3D structure according to a preferred embodiment of the present invention, which includes an insulating layer (not shown), at least one conductive circuit layer (not shown) and at least one solder resist layer (shown in the figure). not shown).

The 3D flexible circuit board 100 includes a first surface 11 and a second surface 12 opposite to the first surface 11 . The first surface 11 has at least one first protruding portion 111, the at least one first protruding portion 111 protrudes along the first surface 11, the second surface 12 has at least one first concave portion 121, the at least one The first concave portion 121 is concave along the second surface 12, and each first protruding portion 111 and a first concave portion 121 are correspondingly arranged on the opposite first surface 11 and the second surface of the flexible circuit board 100 of the 3D structure. Concave-convex structures 13 are thus formed on the two surfaces 12 . The concave-convex structure 13 can be a three-dimensional pattern, and the three-dimensional pattern can be stripes, spiral patterns, miniature three-dimensional grooves and the like. The flexible circuit board 100 with a 3D structure has a 3D structure in a natural state, and the region of the flexible circuit board 100 with a 3D structure having the concave-convex structure 13 has relatively strong rigidity.

The wall thickness of the concave-convex structure 13 is smaller than the wall thickness of the region without the concave-convex structure 13 on the flexible circuit board 100 with 3D structure.

The shape of the 3D-structured flexible circuit board 100 matches the spatial structure of the 3D-structured flexible circuit board 100 used by the electronic device.

The insulating layer of the 3D flexible circuit board 100 is made of amorphous resin. The amorphous resin can be amorphous polyimide (PI), amorphous polyethylene phthalate (PEN), amorphous polyethylene terephthalate ( PET) and other amorphous polymer materials. The material of the conductive circuit layer may be a metal with good ductility (such as copper).

It can be understood that the flexible circuit board 100 with a 3D structure may be a single-layer flexible circuit board or a multi-layer flexible circuit board.

FIG. 1 shows a flexible circuit board 100 with a 3D structure according to an embodiment of the present invention. At least one region of the flexible circuit board 100 with a 3D structure is formed with a concave-convex structure 13 . In this embodiment, the first protruding portion 111 of the 3D-structured flexible circuit board 100 appears as a protrusion, and the first concave portion 121 of the 3D-structured flexible circuit board 100 appears as a ravine.

FIG. 2 is a 3D structure flexible circuit board 100 a according to another embodiment of the present invention, at least one region of the 3D structure flexible circuit board 100 a is formed with a concave-convex structure 13 . In this embodiment, the first protruding portion 111 of the flexible circuit board 100 a with the 3D structure is an n-shaped protrusion, and the first concave portion 121 of the flexible circuit board 100 a with the 3D structure is a U-shaped groove. The thickness of the area of the flexible circuit board 100 a with the 3D structure without the concave-convex structure 13 is D ₁ , the thickness of the side wall of the U-shaped groove is D ₂ , the thickness of the bottom wall of the U-shaped groove is D ₃ , and D ₁ > D ₂ >D ₃ .

FIG. 3 is a 3D structure flexible circuit board 100 b according to another embodiment of the present invention, and at least one region of the 3D structure flexible circuit board 100 b is formed with a concave-convex structure 13 . In this embodiment, the first protruding portion 111 of the flexible circuit board 100 b of the 3D structure appears as a ∧-shaped (inverted V-shaped) protrusion, and the first concave portion 121 of the flexible circuit board 100 b of the 3D structure appears as V-shaped gully. The thickness of the region without the concave-convex structure 13 of the flexible circuit board 100 b with the 3D structure is D ₄ , the wall thickness of the V-shaped groove is D ₅ , and D ₄ >D ₅ .

Please refer to FIGS. 4-5, the method for manufacturing a flexible circuit board (FPC) 100 with a 3D structure according to a preferred embodiment of the present invention. The flexible circuit board 100 with a 3D structure is installed inside an electronic device (not shown in the figure) The shape of the flexible circuit board 100 with a 3D structure matches the spatial structure of the electronic device for mounting the flexible circuit board 100 with a 3D structure. The method for manufacturing the flexible circuit board 100 with a 3D structure includes the following steps.

Step S1: Referring to FIG. 4 , a flat flexible circuit board 200 is provided.

The flat flexible circuit board 200 can be a conventional flexible circuit board, which includes structures such as an insulating layer, a conductive circuit layer, and a solder mask layer (not shown) that a conventional flexible circuit board has. The flat flexible circuit board 200 can be a single-layer flexible circuit board or a multi-layer flexible circuit board. The insulating layer is made of crystalline resin. The crystalline resin can be polyimide (PI), polyethylene terephthalate (PEN), polyethylene terephthalate (PET) and other polymers commonly used in the insulating layer of flexible circuit boards. Material. The material of the conductive circuit layer may be a metal with good ductility (such as copper).

Step S2: Please refer to FIG. 5 further, providing a forming mold 300 .

The molding die 300 itself has the functions of heating and cooling. The molding die 300 has an upper mold 301 and a lower mold 302 matched with the upper mold 301. The upper mold 301 and the lower mold 302 cooperate to form a mold cavity 310. The spatial structure of the mold cavity 310 is used for installing electronic devices. The spatial structure of the 3D flexible circuit board 100 is the same, that is, the spatial structure of the cavity 310 is the same as that of the 3D flexible circuit board 100 to be prepared. The upper mold 301 has a first molding surface 3011 , and the lower mold 302 has a second molding surface 3021 . The first molding surface 3011 has at least one second concave portion 3012, the second concave portion 3012 is concave along the first molding surface 3011, the second molding surface 3021 has at least one second protruding portion 3022, the first molding surface Two protrusions 3022 protrude along the second forming surface 3021 . When the upper mold 301 and the lower mold 302 are laminated, each second concave portion 3012 faces a second protruding portion 3022 . The second recessed portion 3012 is recessed on the first forming surface 3011 to form a three-dimensional groove, and the second protruding portion 3022 protrudes on the second forming surface 3021 to form stripes or spirals. The upper mold 301 may be an airbag structure.

Step S3: placing the flat flexible circuit board 200 in the cavity 310 of the forming mold 300, and rapidly raising the temperature of the forming mold 300, so that the temperature of the flat flexible circuit board 200 reaches the deformation temperature , heat-preservation and pressure-holding to perform thermocompression molding on the flat flexible circuit board 200 to obtain an intermediate body 400 . The intermediate body 400 includes an insulating layer, a conductive circuit layer and a solder resist layer.

Step S4: rapidly cooling the intermediate body 400 at a rate greater than or equal to 10 degrees Celsius per second (°C/S), so that the resin of the insulating layer of the intermediate body 400 changes from a crystalline state to an amorphous state, that is, the flexibility of the 3D structure is obtained For the circuit board 100 , at least one region of the flexible circuit board 100 with a 3D structure has a concave-convex structure 13 .

In the step S3, the second concave portion 3012 is transferred to the first surface 11 of the flexible circuit board 100 of the 3D structure to form the first protrusion 111, and the second protrusion 3022 is transferred to the 3D structure. The first concave portion 121 is formed on the second surface 12 of the flexible circuit board 100 so as to form a concave-convex structure 13 in at least one region of the flexible circuit board 100 with a 3D structure. The concave-convex structure 13 can be a three-dimensional pattern, and the three-dimensional pattern can be stripes, spiral patterns or three-dimensional grooves. The concave-convex structure 13 has strong rigidity, thereby improving the rigidity of the flexible circuit board 100 with a 3D structure.

The deformation temperature of the insulating layer of the flat flexible circuit board 200 is different according to the resin that forms the insulating layer. For example, when the material of the insulating layer is polyimide, the deformation temperature is 150-200 °C. ℃. Rapid cooling of the flat flexible circuit board 200 at a rate greater than or equal to 10°C/S can transform the insulating layer of the flat flexible circuit board 200 from a crystalline state to an amorphous state, so that the final 3D The shape of the structural flexible circuit board 100 is not easily changed.

It can be understood that when the intermediate body 400 is rapidly cooled in the step S4, other resin materials (such as adhesive layers, covering layers, etc.) of the intermediate body 400 other than the insulating layer will also change from crystalline to amorphous. The transformation of the crystalline state further enhances the difficulty of deformation of the fabricated flexible circuit board 100 with 3D structure.

The material of the insulating layer of the 3D structure flexible circuit board 100 of the present invention is amorphous resin, so that the structure of the 3D structure flexible circuit board 100 is stable, and no rebound deformation occurs during use. And the surface of the flexible circuit board 100 with the 3D structure has a concave-convex structure 13 formed by concave or convex stripes, spiral patterns or three-dimensional ravines. Rigidity of the board 100 . In addition, the shape of the flexible circuit board 100 of the 3D structure matches the spatial structure of the electronic device for installing the flexible circuit board 100 of the 3D structure, so that the flexible circuit board 100 of the 3D structure can be directly arranged on the electronic device In terms of the space structure of the flexible circuit board 100 for installing the 3D structure, the use of adhesive tape is avoided, which is beneficial to saving the internal space of the electronic device and reducing the thickness of the electronic device.

In addition, for those skilled in the art, various other corresponding changes and modifications can be made according to the technical concept of the present invention, and all these changes and modifications should belong to the protection scope of the claims of the present invention.

Claims (10)

1. A flexible circuit board with a 3D structure, comprising a first surface and a second surface opposite to the first surface, characterized in that: the first surface has at least one first protruding portion, and the at least one first surface A protrusion protrudes along the first surface, the second surface has at least one first depression, the at least one first depression is concave along the second surface, each first protrusion and a first depression The portions are correspondingly arranged on the opposite first surface and the second surface of the flexible circuit board with the 3D structure to form a concave-convex structure. 2. The flexible circuit board with 3D structure according to claim 1, wherein the concave-convex structure is a three-dimensional pattern. 3. The flexible circuit board with 3D structure according to claim 2, wherein the three-dimensional pattern is a stripe, a spiral pattern or a three-dimensional groove. 4 . The flexible circuit board with 3D structure according to claim 1 , characterized in that: the wall thickness of the concave-convex structure is smaller than the wall thickness of the region without the concave-convex structure on the flexible circuit board with 3D structure. 5. The flexible circuit board with 3D structure as claimed in claim 1, characterized in that: the flexible circuit board with 3D structure has at least one insulating layer, the material of the insulating layer is an amorphous resin, and the amorphous The resin is amorphous resin polyimide, amorphous resin polyethylene phthalate or amorphous resin polyethylene terephthalate. 6. A method for manufacturing a flexible circuit board with a 3D structure, comprising the steps of: Step S1: providing a flat flexible circuit board; Step S2: Provide a forming mold with heating and cooling functions. The forming mold has an upper mold and a lower mold matching the upper mold. The upper mold and the lower mold of the forming mold cooperate to form a mold cavity. The upper mold has a The first molding surface, the lower mold has a second molding surface, the first molding surface has at least one second concave portion, the second concave portion is concave along the first molding surface, and the second molding surface has at least one The second protruding portion protrudes along the second molding surface. When the upper mold and the lower mold are combined, each second concave portion faces a second protruding portion. The upper mold is the airbag structure; Step S3: placing the flat flexible circuit board in the mold cavity, heating the flat flexible circuit board to the deformation temperature of the flat flexible circuit board, and heating the flat flexible circuit board compression molding, to obtain an intermediate; Step S4: cooling the intermediate to produce a flexible circuit board with a 3D structure. 7. The method for manufacturing a flexible circuit board with a 3D structure according to claim 6, characterized in that: the second concave portion is concaved on the first molding surface to form a three-dimensional gully, and the second convex portion is The second molding surface protrudes to form stripes or spiral patterns. 8 . The method for manufacturing a flexible circuit board with a 3D structure according to claim 6 , wherein the cooling rate in step S4 is greater than or equal to 10 degrees Celsius per second. 9. The manufacturing method of the flexible circuit board with 3D structure as claimed in claim 6, characterized in that: the intermediate body has an insulating layer, the material of the insulating layer is a crystalline resin, which is cooled in the step S4 When the intermediate is used, the material of the insulating layer changes from a crystalline state to an amorphous state. 10. An electronic device using the flexible circuit board with a 3D structure according to any one of claims 1 to 5, the shape of the flexible circuit board with a 3D structure is the same as that of the electronic device for installing the flexible circuit board with a 3D structure match the spatial structure.