Preparation method of rigid-flex printed circuit board with main board and auxiliary board having same thickness

Abstract

The invention relates to a preparation method of a rigid-flex board with the same thickness of a main board and an auxiliary board, and the method comprises the following steps: providing a first rigid-flex board and a second rigid-flex board, milling off a first bare board of the first main board, and pasting protective adhesive tapes on the upper surface and the lower surface of the first auxiliary board; the second rigid-flex board comprises a second main board and a second auxiliary board, a second bare board of the second main board is milled off, and protective adhesive tapes are pasted on the upper surface and the lower surface of the second auxiliary board; a first outer layer plate and a second outer layer plate are provided, the first outer layer plate comprises a first pattern area and a first blank area, and the second outer layer plate comprises a second pattern area and a second blank area; the first outer-layer plate, the PP layer, the first rigid-flexible combined plate, the PP layer, the second rigid-flexible combined plate, the PP layer and the second outer-layer plate are laminated and pressed in sequence from top to bottom; and milling off the first blank area and the second blank area, and removing the protective adhesive tape to obtain the rigid-flex board with the main board and the auxiliary board having the same thickness.

Description

Technical Field

[0001] The invention relates to the field of rigid-flex boards, and in particular to a method for preparing a rigid-flex board with a main board and a secondary board having the same thickness. Background Art

[0002] Rigid-Flexible PCB is a circuit board that combines a rigid printed circuit board (PCB) and a flexible printed circuit board (FPC) through a specific process. The rigid part has good mechanical strength and stability, and is usually used to install fixed electronic components such as chips, resistors, capacitors, etc. The flexible part has the characteristics of being bendable and foldable, and can adapt to different spatial layouts and dynamic application requirements.

[0003] In the rigid-flexible board, the rigid area of ​​the rigid-flexible board containing all the layers of circuits is called the main board, which generally refers to the rigid part with thicker board thickness; the rigid area of ​​the rigid-flexible board with only some layers of circuits is called the sub-board, which generally refers to the rigid part with thinner board thickness.

[0004] As the design of rigid-flex boards becomes more and more complex, a process of pressing multiple sub-rigid-flex boards (hereinafter referred to as sub-boards) to form a complex mother rigid-flex board (hereinafter referred to as motherboard) has emerged. In this process, the main board of the daughter board is aligned up and down, and the sub-board of the daughter board is aligned up and down, and then pressed into a motherboard. However, since the main board of the daughter board is thicker than the sub-board, after superposition and pressing, the main board of the motherboard will be much thicker than the sub-board, which is not conducive to the customer's subsequent patch installation and use. Summary of the invention

[0005] In order to overcome the above problems, the present invention provides a method for preparing a rigid-flexible board with a main board and a sub-board of the same thickness. The technical solution adopted by the present invention to solve the technical problem is:

[0006] A method for preparing a rigid-flexible board with a main board and a secondary board having the same thickness, comprising the following steps:

[0007] Step S1: providing a first rigid-flexible board, the first rigid-flexible board comprising a first main board and a first sub-board, the first main board comprising a first empty board, and the first empty board has no graphic design;

[0008] Step S2: mill off the first empty plate, and stick protective tape on the upper and lower surfaces of the first sub-plate;

[0009] Step S3: providing a second rigid-flexible board, the second rigid-flexible board comprising a second main board and a second sub-board, the second main board comprising a second empty board, and the second empty board has no graphic design;

[0010] Step S4: mill off the second empty plate, and stick protective tape on the upper and lower surfaces of the second auxiliary plate;

[0011] Step S5: providing a first outer layer plate and a second outer layer plate, wherein the first outer layer plate includes a first graphic area and a first blank area, and the second outer layer plate includes a second graphic area and a second blank area;

[0012] Step S6: arranging the stack and laminating the stack, the stack order from top to bottom is the first outer layer board, the PP layer, the first rigid-flexible board, the PP layer, the second rigid-flexible board, the PP layer, and the second outer layer board; the projection of the PP layer on the first main board / the second main board overlaps with the first main board / the second main board;

[0013] Step S7: mill off the first blank area and the second blank area, remove the protective tape, and obtain a rigid-flexible board with the same thickness as the main board and the auxiliary board.

[0014] Furthermore, the first rigid-flexible board and the second rigid-flexible board are both sub-rigid-flexible boards that have undergone lamination, drilling, electroplating, pattern transfer, surface treatment, solder mask and text processing.

[0015] Furthermore, the first main board and the first sub-board are connected via a flexible board, and the second main board and the second sub-board are connected via a flexible board.

[0016] Furthermore, in step S2, the first empty plate is milled off by controlled depth milling; and in step S4, the second empty plate is milled off by controlled depth milling.

[0017] Further, in step S6, the first graphic area pair is located directly above the first main board, the first main board pair is located directly above the second main board, and the second main board pair is located directly above the second graphic area to form a rigid main board structure.

[0018] Furthermore, the first blank area is located above the first sub-panel to protect the first sub-panel; the first sub-panel pair is located directly above the second sub-panel to form a rigid sub-panel structure; and the second blank area is located below the second sub-panel to protect the second sub-panel.

[0019] Furthermore, between step S6 and step S7, drilling, electroplating, pattern transfer, surface treatment, solder mask, text and molding processes are also included to make through holes on the rigid mainboard structure and complete the production of graphic circuits in the first graphic area and the second graphic area.

[0020] Furthermore, in step S7, the first blank area and the second blank area are milled away by milling a blind groove.

[0021] The beneficial effects of the present invention are:

[0022] The method includes the following steps: providing a first rigid-flexible board and a second rigid-flexible board, the first rigid-flexible board includes a first main board and a first sub-board, milling off the first empty board of the first main board and attaching protective tape to the upper and lower surfaces of the first sub-board; the second rigid-flexible board includes a second main board and a second sub-board, milling off the second empty board of the second main board and attaching protective tape to the upper and lower surfaces of the second sub-board; providing a first outer layer board and a second outer layer board, the first outer layer board includes a first graphic area and a first blank area, and the second outer layer board includes a second graphic area and a second blank area; stacking and pressing the boards in the order of the first outer layer board, PP layer, first rigid-flexible board, PP layer, second rigid-flexible board, PP layer and second outer layer board from top to bottom; milling off the first blank area and the second blank area, and removing the protective tape. The method first mills off the empty layer structure of the main board of the daughter board, and then presses it together to obtain a rigid-flexible board with the same thickness as the main board and the sub-board. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, wherein:

[0024] Figure 1 The stacked cross section of the first rigid-flexible board and the second rigid-flexible board of the present invention is Figure 1 ;

[0025] Figure 2 The stacked cross section of the first rigid-flexible board and the second rigid-flexible board of the present invention is Figure 2 ;

[0026] Figure 3 The stacked cross section of the first rigid-flexible board and the second rigid-flexible board of the present invention is Figure 3 ;

[0027] Figure 4 It is an exploded cross-sectional view of the stacked structure of the rigid-flexible board with the same thickness of the main board and the auxiliary board before being pressed together;

[0028] Figure 5 It is a cross-sectional view of a stacked structure of a rigid-flexible board having a main board and a secondary board of the same thickness according to the present invention;

[0029] Figure 6 It is a cross-sectional view of the stacked structure of a rigid-flexible board in the prior art.

[0030] Figure number marking:

[0031] 100, first rigid-flex board; 101, first main board; 1011, first empty board; 102, first auxiliary board;

[0032] 200, second rigid-flex board; 201, second main board; 2011, second empty board; 202, second auxiliary board;

[0033] 300, first outer layer plate; 301, first graphic area; 302, first blank area;

[0034] 400, second outer layer plate; 401, second graphic area; 402, second blank area;

[0035] 500, PP layer;

[0036] 600. Protective tape. DETAILED DESCRIPTION

[0037] In order to better understand the purpose, structure and function of the present invention, the specific embodiment of the present invention "a method for preparing a rigid-flexible composite board with the same thickness of the main board and the sub-board" is further described in detail below in conjunction with the accompanying drawings.

[0038] In the prior art, two sub-rigid-flex boards (hereinafter referred to as sub-boards) are pressed together to form a complex mother rigid-flex board (hereinafter referred to as motherboard), the main board of the sub-board is aligned up and down, and the sub-board of the sub-board is aligned up and down, and then pressed into the motherboard. However, since the main board of the sub-board itself is thicker than the sub-board, after superposition and pressing, the main board of the motherboard will be much thicker than the sub-board. Figure 6 In the case of such a large thickness difference, it is not conducive to the subsequent installation and use of the patch by the customer; therefore, based on this problem, the present invention provides a method for preparing a rigid-flexible board with the same thickness of the main board and the auxiliary board, which mainly includes the following steps:

[0039] Step S1: See Figure 1 , providing a first rigid-flexible board 100, the first rigid-flexible board 100 comprising a first main board 101 and a first sub-board 102, the first main board 101 comprising a first empty board 1011, and the first empty board 1011 has no graphic design;

[0040] Step S2: See Figure 2 and Figure 3 , mill off the first empty plate 1011, and stick protective tape 600 on the upper and lower surfaces of the first sub-plate 102 to protect and isolate the first sub-plate 102;

[0041] Step S3: See Figure 1 , providing a second rigid-flexible board 200, the second rigid-flexible board 200 includes a second main board 201 and a second sub-board 202, the second main board 201 includes a second empty board 2011, and the second empty board 2011 has no graphic design;

[0042] Step S4: See Figure 2 and Figure 3 , mill off the second empty plate 2011, and stick protective tape 600 on the upper and lower surfaces of the second sub-plate 202 to protect and isolate the second sub-plate 202;

[0043] Step S5: providing a first outer layer plate 300 and a second outer layer plate 400, wherein the first outer layer plate 300 includes a first graphic area 301 and a first blank area 302, and the second outer layer plate 400 includes a second graphic area 401 and a second blank area 402. In this step, the first graphic area 301 and the first blank area 302, the second graphic area 401 and the second blank area 402 are all core plates without patterns;

[0044] Step S6: arranging the stack and pressing, see Figure 5 , the stacking order from top to bottom is the first outer layer board 300, the PP layer 500, the first rigid-flex board 100, the PP layer 500, the second rigid-flex board 200, the PP layer 500 and the second outer layer board 400; the projection of the PP layer 500 on the first main board 101 / the second main board 201 overlaps with the first main board 101 / the second main board 201, so that in the subsequent lamination process, the PP layer 500 bonds the first graphic area 301, the first main board 101, the second main board 201 and the second graphic area 401 together and plays a role in electrical insulation;

[0045] Step S7, milling off the first blank area 302 and the second blank area 402, removing the protective tape 600, and obtaining the following Figure 5 The main board and the sub-board have the same thickness.

[0046] See also Figure 1 In this embodiment, the first rigid-flexible board 100 and the second rigid-flexible board 200 are both sub-rigid-flexible boards that have undergone pressing, drilling, electroplating, pattern transfer, surface treatment, solder mask and text processing; the first main board 101 and the first sub-board 102 are connected by a flexible board, and the second main board 201 and the second sub-board 202 are connected by a flexible board.

[0047] See also Figure 2 In this embodiment, the first empty plate 1011 is milled off by controlled depth milling in step S2, and the second empty plate 2011 is milled off by controlled depth milling in step S4 to reduce the thickness of the main board.

[0048] See also Figure 5 In the present embodiment, in step S6, the shape and size of the first main board 101 in the first graphic area 301 are consistent with the first main board 101, and it is located directly above the first main board 101; the shape and size of the first main board 101 are consistent with the second main board 201, and it is located directly above the second main board 201; the shape and size of the second main board 201 are consistent with the second graphic area 401, and it is located directly above the second graphic area 401. The above stacked structure forms a rigid main board structure.

[0049] More specifically, in the present embodiment, in step S6, the first blank area 302 is located above the first sub-panel 102 to protect the first sub-panel 102 and prevent the first sub-panel 102 from being corroded and damaged in subsequent processes; the first sub-panel 102 is consistent in shape and size with the second sub-panel 202, and is located directly above the second sub-panel 202 to form a rigid sub-panel structure; the second blank area 402 is located below the second sub-panel 202 to protect the second sub-panel 202 and prevent the second sub-panel 202 from being corroded and damaged in subsequent processes.

[0050] It should be noted that, in this embodiment, between step S6 and step S7, drilling, electroplating, pattern transfer, surface treatment, solder mask, text and molding processes are also included. After these processes, through holes can be made on the rigid mainboard structure, and the production of the graphic circuits of the first graphic area 301 and the second graphic area 401 can be completed.

[0051] Furthermore, since protective tape 600 is affixed to the upper and lower surfaces of the first sub-panel 102 and protective tape 600 is affixed to the upper and lower surfaces of the second sub-panel 202, in the subsequent lamination process, there is no PP layer 500 between the first blank area 302 and the first sub-panel 102 and between the second blank area 402 and the second sub-panel 202, so they will not be bonded together. In step S7, the connection between the first blank area 302 and the first graphic area 301 and the connection between the second blank area 402 and the second graphic area 401 are cut off by milling blind grooves, and the first blank area 302 and the second blank area 402 can be removed.

[0052] In summary, this method utilizes the structure of the main board of the rigid-flexible board with an empty board without graphic circuit design. The first empty board 1011 and the second empty board 2011 are first milled off by controlled depth milling, and then pressed together, so that a rigid-flexible board with the same thickness of the main board and the sub-board can be obtained. During the pressing process, the first blank area 302 of the first outer layer board 300 and the second blank area 402 of the second outer layer board 400 are retained to protect the first sub-board 102 and the second sub-board 202 of the daughter board, and prevent these sub-boards that have completed circuit production from being corroded or damaged in the subsequent drilling, electroplating, graphic transfer, surface treatment, solder mask, text and molding processes of the main board, thereby ensuring the finished product quality of the sub-board. Using this method, a high-quality rigid-flexible board with a main board and sub-board of the same thickness can be obtained, which solves the problem that the thickness of the main board of a high-layer rigid-flexible board is much larger than the thickness of the sub-board.

[0053] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

[0054] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying 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 limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

Claims

1. A method for preparing a rigid-flexible board with a main board and a secondary board having the same thickness, characterized in that: The steps include: Step S1: providing a first rigid-flexible board (100), wherein the first rigid-flexible board (100) comprises a first main board (101) and a first sub-board (102), wherein the first main board (101) comprises a first empty board (1011), and the first empty board (1011) has no graphic design; Step S2: milling off the first empty plate (1011), and sticking protective tape (600) on the upper and lower surfaces of the first auxiliary plate (102); Step S3: providing a second rigid-flex board (200), wherein the second rigid-flex board (200) comprises a second main board (201) and a second sub-board (202), wherein the second main board (201) comprises a second empty board (2011), and the second empty board (2011) has no graphic design; Step S4: milling off the second empty plate (2011), and sticking protective tape (600) on the upper and lower surfaces of the second auxiliary plate (202); Step S5: providing a first outer layer plate (300) and a second outer layer plate (400), wherein the first outer layer plate (300) comprises a first graphic area (301) and a first blank area (302), and the second outer layer plate (400) comprises a second graphic area (401) and a second blank area (402); Step S6: arranging the stack and laminating the stack, wherein the stack is arranged in the order of the first outer layer board (300), the PP layer (500), the first rigid-flexible board (100), the PP layer (500), the second rigid-flexible board (200), the PP layer (500), and the second outer layer board (400) from top to bottom; the projection of the PP layer (500) on the first main board (101) / the second main board (201) overlaps with the first main board (101) / the second main board (201); Step S7: mill off the first blank area (302) and the second blank area (402), remove the protective tape (600), and obtain a rigid-flexible board with the same thickness for the main board and the auxiliary board.

2. The method for preparing a rigid-flexible board with a main board and a sub-board of the same thickness according to claim 1, characterized in that: The first rigid-flex board (100) and the second rigid-flex board (200) are both sub-rigid-flex boards that have undergone lamination, drilling, electroplating, pattern transfer, surface treatment, solder mask and text processing.

3. The method for preparing a rigid-flexible board with a main board and a secondary board having the same thickness as claimed in claim 2, characterized in that: The first main board (101) and the first sub-board (102) are connected via a flexible board, and the second main board (201) and the second sub-board (202) are connected via a flexible board.

4. The method for preparing a rigid-flexible board with a main board and a sub-board having the same thickness as claimed in claim 1, characterized in that: In the step S2, the first empty plate (1011) is milled out by controlled depth milling; and in the step S4, the second empty plate (2011) is milled out by controlled depth milling.

5. The method for preparing a rigid-flexible board with a main board and a sub-board having the same thickness as claimed in claim 1, characterized in that: In step S6, the first graphic area (301) is located directly above the first main board (101), the first main board (101) is located directly above the second main board (201), and the second main board (201) is located directly above the second graphic area (401) to form a rigid main board structure.

6. The method for preparing a rigid-flexible board with a main board and a secondary board having the same thickness as claimed in claim 5, characterized in that: The first blank area (302) is located above the first sub-panel (102) to protect the first sub-panel (102); the first sub-panel (102) is located directly above the second sub-panel (202) to form a rigid sub-panel structure; and the second blank area (402) is located below the second sub-panel (202) to protect the second sub-panel (202).

7. The method for preparing a rigid-flexible board with a main board and a secondary board having the same thickness as claimed in claim 6, characterized in that: Between step S6 and step S7, drilling, electroplating, pattern transfer, surface treatment, solder mask, text and molding processes are also included to make through holes on the rigid mainboard structure and complete the production of the graphic circuits of the first graphic area (301) and the second graphic area (401).

8. The method for preparing a rigid-flexible board with a main board and a sub-board of the same thickness according to claim 7, characterized in that: In the step S7, the first blank area (302) and the second blank area (402) are milled away by milling blind grooves.

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