Multilayer circuit board and electronic device

Abstract

The present invention provides a multilayer circuit board and an electronic device. The multilayer circuit board includes a circuit unit layer; the circuit unit layer includes at least two circuit layers arranged in parallel and spaced apart from each other and an insulating layer sandwiched between adjacent circuit layers; the surfaces arranged opposite to each other along the thickness direction of the circuit unit layer are a first side surface and a second side surface; the circuit unit layer is provided with a through hole arranged through along its thickness direction, the through hole is formed by surrounding an inner side wall, a first copper plating layer is provided on the first side surface or the second side surface, a second copper plating layer connected to the first copper plating layer is plated on the inner side wall, and at least two circuit layers are connected in parallel through the second copper plating layer. The multilayer circuit board of the present invention reduces the overall thickness of the multilayer circuit board and reduces the space requirement for installing the multilayer circuit board while realizing the parallel connection between the circuit layers, effectively controlling the resistance value of the circuit board, and meeting the performance requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a multilayer circuit board and electronic equipment. Background Art

[0002] With the rapid development of electronic products, different electronic products have different resistance values. In circuit design, some electronic products have resistance value restrictions. In electronic products in the prior art, in order to reduce the circuit resistance of the circuit board, the resistance value of the conductor can usually be reduced by reducing the circuit line length, increasing the conductor thickness, and increasing the conductor line width. However, due to the limitation of the installation structure space of electronic products, it is impossible to reduce the resistance value by increasing the conductor thickness.

[0003] Therefore, it is necessary to provide a multilayer circuit board and electronic device that can meet the requirements of both the required installation space and resistance performance. Summary of the invention

[0004] The object of the present invention is to provide a multilayer circuit board, which has a small thickness and can meet the structural space requirements of the product, and can effectively control the resistance value and meet the performance requirements of the resistance value of electronic products.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a multilayer circuit board, comprising a circuit unit layer; the circuit unit layer comprises at least two circuit layers arranged in parallel and spaced apart from each other and an insulating layer sandwiched between adjacent circuit layers; surfaces arranged opposite to each other along the thickness direction of the circuit unit layer are a first side surface and a second side surface; the circuit unit layer is provided with a via hole extending through the thickness direction thereof, the via hole being formed by surrounding an inner side wall, only the first side surface or the second side surface being provided with a first copper plating layer, the inner side wall being coated with a second copper plating layer connected to the first copper plating layer, and at least two circuit layers being connected in parallel via the second copper plating layer.

[0006] Optionally, an end of the second copper-plated layer facing away from the first copper-plated layer is flush with one of the first side surface and the second side surface on which the first copper-plated layer is not provided.

[0007] Optionally, the circuit unit layer further includes an outer side wall arranged opposite to the inner side wall, and the first copper plating layer extends to be flush with the outer side wall.

[0008] Optionally, there are multiple vias, and the multiple vias are arranged at intervals.

[0009] Optionally, the circuit unit layer includes three circuit layers that are arranged parallel to each other and two insulating layers that are respectively arranged between adjacent circuit layers.

[0010] Optionally, the line lengths of the three circuit layers are consistent, and the three circuit layers are connected in parallel through the second copper-plated layer in the conducting hole.

[0011] Optionally, the line layers of the three circuit layers are not completely consistent, and the three circuit layers are connected in parallel through the second copper plating layer in the conducting hole.

[0012] Optionally, the conducting hole is a cylindrical hole.

[0013] Optionally, the circuit board may be a flexible circuit board, a rigid circuit board, or a rigid-flexible circuit board.

[0014] In a second aspect, the present invention provides an electronic device, wherein the electronic device comprises the multilayer circuit board as described above and the electronic device comprises a voice coil motor.

[0015] The beneficial effects of the present invention are: The multilayer circuit board of the present invention comprises a first copper-plated layer provided on the first side surface or the second side surface of the circuit unit layer, and a second copper-plated layer provided on the inner side wall of the through hole; the second copper-plated layer is connected to the first copper-plated layer. The structure of the multilayer circuit board is set up such that the first copper-plated layer is plated only on one side surface of the circuit unit layer, and the other side of the circuit unit layer is not provided with a copper-plated layer. In the thickness direction, only one side of the circuit unit layer is thickened, so that the overall thickness of the multilayer circuit board is reduced while achieving parallel connection between the circuit layers, effectively controlling the resistance value of the circuit board, and meeting the performance requirements, and reducing the space requirement for the installation of the multilayer circuit board; the first copper-plated layer forms a protective layer for the circuit layer and increases the thickness of the conductor to a certain extent, reducing the resistance value of the multilayer circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of a multilayer circuit board of the present invention.

[0017] Figure 2 It is a schematic structural diagram of the surface of the multi-layer circuit board of the present invention that is not plated with the first copper plating layer.

[0018] Figure 3 It is another structural schematic diagram of the surface of the multi-layer circuit board of the present invention that is not plated with the first copper plating layer. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0020] In a first aspect, the present invention provides a multilayer circuit board, referring to Figures 1 to 3As shown, it includes a circuit unit layer 10; the circuit unit layer 10 includes at least two circuit layers 11 arranged in parallel and spaced apart from each other and an insulating layer 12 sandwiched between the adjacent circuit layers 11; the surfaces arranged oppositely along the thickness direction of the circuit unit layer 10 are a first side surface 14 and a second side surface 15; the circuit unit layer 10 is provided with a through hole 13 arranged through along the thickness direction thereof, the through hole 13 is formed by surrounding an inner side wall 16, only the first side surface 14 or the second side surface 15 is provided with a first copper plating layer 20, the inner side wall 16 is plated with a second copper plating layer 30 connected to the first copper plating layer 20, and at least two circuit layers 11 are connected in parallel through the second copper plating layer 30. That is, the circuit unit layer 10 is formed by stacking the insulating layer 12 and the circuit layer 11 to form two oppositely arranged surfaces, and the first copper plating layer 20 is provided on one of the side surfaces.

[0021] The multilayer circuit board of the present invention comprises a first copper-plated layer 20 provided on the first side surface 14 or the second side surface 15 of the circuit unit layer 10, and a second copper-plated layer 30 provided on the inner side wall 16 of the through hole 13; the second copper-plated layer 30 is connected to the first copper-plated layer 20. The structure of the multilayer circuit board is set up such that the first copper-plated layer 20 is plated only on one side surface of the circuit unit layer 10, and the first copper-plated layer 20 is not provided on the other side of the circuit unit layer 10. In the thickness direction, only one side of the circuit unit layer 10 is thickened, so that the overall thickness of the multilayer circuit board is reduced while achieving the parallel connection between the circuit layers 11, effectively controlling the resistance value of the circuit board, and meeting the performance requirements, and reducing the space requirement for the installation of the multilayer circuit board; the first copper-plated layer 20 forms a protective layer for the circuit layer 11 and increases the thickness of the conductor to a certain extent, reducing the resistance value of the multilayer circuit board.

[0022] Optionally, one end of the second copper plating layer 30 facing away from the first copper plating layer 20 is flush with the surface where the first copper plating layer 20 is not provided.

[0023] Optionally, the circuit unit layer 10 further includes an outer side wall 17 disposed opposite to the inner side wall 16 , and the first copper plating layer 20 extends to be flush with the outer side wall 17 .

[0024] See also Figure 3 As shown, optionally, the number of the vias 13 is multiple, and the multiple vias are arranged at intervals. The vias 13 are used to enable the circuit layers 11 to be connected in parallel. The more the number of vias 13 is set, the greater the resistance reduction, and the resistance value of the multi-layer circuit board can be further effectively controlled. It is understandable that the number of vias 13 can be specifically set according to actual performance requirements.

[0025] Optionally, the circuit layer 11 is made of copper; and the insulating layer 12 is made of a composite material of insulating material and adhesive.

[0026] Optionally, the insulating material includes one or more of insulating ink, polyimide or polyethylene naphthalate.

[0027] See also Figure 1 As shown, in a specific embodiment of the present invention, the circuit unit layer 10 includes three circuit layers 11 arranged in parallel and spaced apart from each other and two insulating layers 12 respectively arranged between adjacent circuit layers 11; the circuit layers 11 and the insulating layers 12 are stacked in sequence, and the insulating layers 12 are sandwiched between the circuit layers 11; the conductive holes 13 are arranged to penetrate the circuit unit layer 10 along the thickness direction.

[0028] The two ends of three mutually parallel circuit layers 11 are connected in parallel through the conducting hole 13, thereby effectively controlling the circuit resistance value and reducing excessive heat generation during circuit operation; no copper plating layer is provided on the other side surface of the circuit unit layer 10, thereby reducing the overall thickness of the multi-layer circuit board and the installation space required for installation.

[0029] Optionally, the insulating layer 12 may be a single-layer structure made of a composite material of an insulating material and an adhesive, or a multi-layer structure formed by stacking a single-layer structure made of a composite material of an insulating material and an adhesive for multiple times; of course, the circuit layer 11 is not limited to a single-layer structure; by setting different circuit layers 11, the parallel design between the circuit layers 11 can be adjusted.

[0030] Optionally, the line lengths of the three circuit layers are consistent, and the three circuit layers are connected in parallel through the second copper-plated layer in the conducting hole.

[0031] Optionally, the line layers of the three circuit layers are not completely consistent, and the three circuit layers are connected in parallel through the second copper plating layer in the conducting hole.

[0032] Optional, see Figure 2 and Figure 3 As shown, the conducting hole 13 is a cylindrical hole, that is, the cross section of the conducting hole 13 is circular.

[0033] Optionally, the multilayer circuit board may be a flexible printed circuit board (FPC), a rigid printed circuit board (PCB), or a rigid-flexible circuit board (R-FPCB).

[0034] In a second aspect, the present invention provides an electronic device, wherein the electronic device comprises the multilayer circuit board as described above. The electronic device comprises a voice coil motor (VCM).

[0035] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A multilayer circuit board, characterized in that: It comprises a circuit unit layer; the circuit unit layer comprises at least two circuit layers arranged in parallel and spaced apart from each other and an insulating layer sandwiched between adjacent circuit layers; surfaces arranged opposite to each other along the thickness direction of the circuit unit layer are a first side surface and a second side surface; the circuit unit layer is provided with a via hole penetrating along the thickness direction thereof, the via hole is formed by surrounding an inner side wall, only the first side surface or the second side surface is provided with a first copper plating layer, the inner side wall is plated with a second copper plating layer connected to the first copper plating layer, and at least two circuit layers are connected in parallel via the second copper plating layer.

2. The multilayer circuit board according to claim 1, characterized in that: An end of the second copper plating layer facing away from the first copper plating layer is flush with one of the first side surface and the second side surface on which the first copper plating layer is not disposed.

3. The multilayer circuit board according to claim 1, characterized in that: The circuit unit layer further includes an outer side wall arranged opposite to the inner side wall, and the first copper plating layer extends to be flush with the outer side wall.

4. The multilayer circuit board according to claim 1, characterized in that: There are multiple vias, and the multiple vias are arranged at intervals.

5. The multilayer circuit board according to claim 1, characterized in that: The circuit unit layer includes three circuit layers which are arranged in parallel and spaced apart from each other and two insulating layers which are respectively arranged between adjacent circuit layers.

6. The multilayer circuit board according to claim 5, characterized in that: The line lengths of the three circuit layers are consistent, and the three circuit layers are connected in parallel through the second copper-plated layer in the conducting hole.

7. The multilayer circuit board according to claim 5, characterized in that: The line layers of the three circuit layers are not completely consistent, and the three circuit layers are connected in parallel through the second copper plating layer in the conducting hole.

8. The multilayer circuit board according to claim 1, characterized in that: The conducting hole is a cylindrical hole.

9. The multilayer circuit board according to claim 3, characterized in that: The multilayer circuit board is one of a flexible circuit board, a rigid circuit board or a rigid-flexible circuit board.

10. An electronic device, characterized in that: The electronic device includes the multilayer wiring board as claimed in claim 1.

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