Rigid-flex board pressing structure with inner layer copper thickness larger than 70 [mu] m

Abstract

The utility model discloses a rigid-flex board press-fit structure with the inner copper thickness larger than 70 microns. A thick copper plate, thickening glue, a CVL layer, a filling layer and a press plate are sequentially stacked from bottom to top. The heated and softened thickening glue flows into a circuit gap of the thick copper plate under the pressure of the pressing plate, and the heated and softened filling layer flows into each recess between the pressing plate and the thick copper plate; the thickness of the glue body on the CVL layer can be increased through the arrangement of the thickening glue, so that the thickening glue is softened and flows into the line gap of the thick copper plate during heating and pressing, full filling is carried out, and the product quality is ensured; after being heated, the filling film is softened and flows into each recess between the pressing plate and the thick copper plate for filling, so that when the pressing plate is pressed downwards, the pressure can uniformly act on the pressing structure; due to the arrangement of the double-sided release film of the filling layer, the whole filling layer can be removed after pressing is completed, and bonding is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, and more specifically to a soft-hard board pressing structure with an inner copper layer thickness greater than 70 μm. Background Art

[0002] A rigid-flex PCB is a circuit board technology that integrates flexible and rigid circuit boards. This design allows electronic devices to bend, fold, or connect different surfaces using the flexible portion while maintaining the structural support of the rigid portion. When manufacturing a rigid-flex PCB, thick copper circuit patterns require glue filling using a lamination method.

[0003] In the existing technology, when filling glue, the CVL layer is laminated on the thick copper plate. The CVL layer includes a PI layer and a glue layer. The glue layer is relatively thin, about 35um thick. When the thickness of the inner copper layer on the thick copper plate is greater than 70um, the filling will not be in place, and there will be depressions inside the stacked plate during the pressing process, resulting in uneven pressure when pressed. Utility Model Content

[0004] In response to the problems existing in the prior art, the purpose of the present invention is to provide a soft-hard board pressing structure with an inner copper thickness greater than 70um, which can fully fill the copper layer circuit gaps and ensure uniform pressure during pressing.

[0005] To solve the above problems, the present invention adopts the following technical solution: a soft-hard plate pressed structure with an inner copper layer thickness greater than 70 μm, in which a thick copper plate, thickened adhesive, CVL layer, filling layer, and pressing plate are stacked in order from bottom to top; the heat-softened thickened adhesive flows into the gaps in the thick copper plate circuits under the pressure of the pressing plate, and the heat-softened filling layer flows into the various recesses between the pressing plate and the thick copper plate;

[0006] The filling layer includes a filling film and release films located on the upper and lower surfaces of the filling film.

[0007] Preferably, the thickening glue is epoxy resin or modified epoxy resin.

[0008] Preferably, the thickness of the thickened glue is greater than 50um.

[0009] Preferably, the filling film is a PE filling film or a PVC filling film.

[0010] Preferably, the CVL layer includes a PI layer and a glue layer located at the bottom of the PI layer;

[0011] Preferably, the pressing plate is made of steel plate.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The setting of thickened glue can thicken the thickness of the glue on the CVL layer, and then when heated and pressed, the thickened glue softens and flows into the circuit gaps of the thick copper plate to fully fill it and ensure product quality; the filling film softens after being heated and flows into the various recesses between the pressing plate and the thick copper plate to fill it, so that when the pressing plate is pressed down, the pressure can be evenly applied to the pressed structure; the setting of double-sided release film of the filling layer allows the filling layer to be removed as a whole after pressing is completed to prevent adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the existing rigid-flex board pressing structure;

[0015] Figure 2 This is a schematic diagram of the soft-hard combined board stacking structure of the present utility model;

[0016] Figure 3 This is a schematic diagram of the structure of the rigid-flexible board after lamination of the present invention;

[0017] Figure 4 This is a finished product picture of the rigid-flex board of this utility model.

[0018] Description of the numbers in the figure:

[0019] 1. Thick copper plate; 11. Copper layer; 12. Base material; 2. CVL layer; 21. PI layer; 22. Adhesive layer; 3. Thickened adhesive; 4. Filling layer; 41. Filling film; 42. Release film; 5. Pressing plate. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] In the prior art, when filling glue, the CVL layer 2 is pressed on the thick copper plate 1. The CVL layer 2 includes a PI layer 21 and a glue layer 22. The glue layer 22 is relatively thin, about 35um thick. The thick copper plate 1 includes a substrate 12 and a copper layer 11. When the inner copper thickness of the thick copper plate 1 is greater than 70um, refer to Figure 1 Due to the limited thickness of the adhesive layer 22, the circuit gaps on the copper layer 11 may not be filled properly. In addition, there are depressions inside the stacked boards during the pressing process, resulting in uneven pressure when pressed.

[0022] Based on this, the present invention provides the following embodiments.

[0023] refer to Figure 2The inner copper thickness is greater than 70um, and the soft and hard board pressing structure is stacked from bottom to top with a thick copper plate 1, a thickened glue 3, a CVL layer 2, a filling layer 4, and a pressing plate 5; the heat-softened thickened glue 3 flows into the circuit gap of the thick copper plate 1 under the pressure of the pressing plate 5, and the heat-softened filling layer 4 flows into the various depressions between the pressing plate 5 and the thick copper plate 1; the filling layer 4 includes a filling film 41 and a release film 42 located on the upper and lower surfaces of the filling film 41.

[0024] It can be understood that the thickening glue 3 is a material that is filled in the gaps in the copper layer 11 circuits. For example, it can be epoxy resin or modified epoxy resin, etc., but it is not limited to this. The filling film 41 is a material used to fill the depression between the pressing plate 5 and the thick copper plate 1. The design of the filling film 41 and the double-sided release film 42 adopted here, the filling film 41 can be a PE filling film or a PVC filling film, etc., but it is not limited to this. The release film 42 serves as an auxiliary pressing function to facilitate the subsequent removal of the filling layer 4. The pressing plate 5 is a component for pressing the thick copper plate 1, the thickening glue 3, the CVL layer 2, and the filling layer 4 stacked together. For example, it can be a steel plate or an acrylic plate, etc., but it is not limited to this.

[0025] So set up, refer to Figure 3 First, apply the thickened adhesive 3 to the adhesive side of the CVL layer 2. Then, from bottom to top, stack the thick copper plate 1, the CVL layer 2 with the thickened adhesive 3, and the filling layer 4. Finally, place the pressure plate 5 at the top. As the pressure plate 5 presses down and heats, the thickened adhesive 3 softens and flows into the circuit gaps of the thick copper plate 1, fully filling them. The filling film 41 softens after being heated and flows into the various recesses between the pressure plate 5 and the thick copper plate 1 to fill them. In this way, when the pressure plate 5 presses down, the pressure can be evenly applied to the pressed structure. Figure 4 Finally, remove the filler, 4, and obtain the finished rigid-flex board. Of course, here only describes the lamination of the single-sided copper layer 11 of the thick copper plate 1. On the thick copper plate 1 with double-sided copper layer 11, the double-sided stacking and lamination can be performed.

[0026] For example, the thickness of the thickening glue 3 is greater than 50um, for example, 55um, 60um, 70um, 80um, etc., but not limited thereto. The thickness of the thickening glue 3 can be selected according to the thickness of the copper layer 11 of the thick copper plate 1.

[0027] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any person skilled in the art who, within the technical scope disclosed in the present invention, makes equivalent substitutions or modifications based on the technical solutions and improved concepts of the present invention shall be covered by the scope of protection of the present invention.

Claims

1. The inner copper thickness is greater than 70um, and the soft and hard board pressing structure is characterized by: From bottom to top, thick copper plate, thickened glue, CVL layer, filling layer, and pressing plate are stacked in sequence; the thickened glue softened by heat flows into the gaps in the thick copper plate circuits under the pressure of the pressing plate, and the filling layer softened by heat flows into the various recesses between the pressing plate and the thick copper plate; The filling layer includes a filling film and release films located on the upper and lower surfaces of the filling film.

2. The soft-hard board press-fit structure with an inner copper layer thickness greater than 70 μm according to claim 1, characterized in that: The thickening glue is epoxy resin or modified epoxy resin.

3. The soft-hard board press-fit structure with an inner copper layer thickness greater than 70 μm according to claim 1, characterized in that: The thickness of the thickened glue is greater than 50um.

4. The soft-hard board press-fit structure with an inner copper layer thickness greater than 70 μm according to claim 1, characterized in that: The filling film is a PE filling film or a PVC filling film.

5. The soft-hard board press-fit structure with an inner copper layer thickness greater than 70 μm according to claim 1, characterized in that: The CVL layer includes a PI layer and a glue layer located at the bottom of the PI layer.

6. The soft-hard board press-fit structure with an inner copper layer thickness greater than 70 μm according to claim 1, characterized in that: The pressing plate is made of steel plate.

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