Circuit board and display device

Abstract

A circuit board comprises a thinned region and a non-thinned region; the non-thinned region comprises a first electromagnetic shielding layer, a first composite structure layer and a substrate layer which are sequentially stacked; the first composite structure layer comprises a first substructure layer and a second substructure layer which are sequentially stacked away from the substrate layer, and the first substructure layer and the second substructure layer each comprise at least one circuit layer; the thinned region comprises a third electromagnetic shielding layer, the first substructure layer and the substrate layer which are sequentially stacked; an insulating material is arranged at the junction of the thinned region and the non-thinned region, and the insulating material insulates the circuit layer in the second substructure layer from the third electromagnetic shielding layer; or, the first composite structure layer comprises at least one circuit layer; the thinned region comprises a third electromagnetic shielding layer and the substrate layer which are sequentially stacked; an insulating material is arranged at the junction of the thinned region and the non-thinned region, and the insulating material insulates the circuit layer in the first composite structure layer from the third electromagnetic shielding layer.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure relates to the technical field of circuit board, in particular to a circuit board and a display device. BACKGROUND

[0002] At present, the design function of mobile phone is more and more rich, which puts forward higher requirements for the whole machine space. In some technologies, due to the limitation of the whole machine space, the local area of the flexible circuit board (FPC) of the mobile phone needs to be thinned for designing other devices. The thinned area of the FPC will be attached with an electromagnetic shielding (EMI) film after removing at least one copper layer. Due to the attachment precision and process problems, the EMI film in the thinned area will be connected with the copper in the surrounding non-thinned area, which will cause short circuit. In addition, due to the thickness difference between the thinned area and the non-thinned area, the junction between the thinned area and the non-thinned area is not covered by the EMI film, which will cause electromagnetic leakage and electromagnetic interference. In addition, during the bending process of the FPC, stress concentration will occur at the junction between the thinned area and the non-thinned area, which will cause the problem of trace breakage. SUMMARY

[0003] The embodiment of the present disclosure provides a circuit board, which comprises a main body part, the main body part comprises a thinned area and a non-thinned area; the non-thinned area comprises a first electromagnetic shielding layer, a first composite structure layer, a substrate layer, a second composite structure layer and a second electromagnetic shielding layer which are sequentially stacked; the second composite structure layer comprises at least one circuit layer;

[0004] The first composite structure layer comprises a first substructure layer and a second substructure layer which are sequentially stacked away from the substrate layer, and the first substructure layer and the second substructure layer each comprise at least one circuit layer; the thinned area comprises a third electromagnetic shielding layer, a first substructure layer, a substrate layer, a second composite structure layer and a second electromagnetic shielding layer which are sequentially stacked; at the junction between the thinned area and the non-thinned area, an insulating material is arranged between the second substructure layer and the third electromagnetic shielding layer, and the insulating material insulates the circuit layer in the second substructure layer from the third electromagnetic shielding layer;

[0005] Alternatively, the first composite structure layer comprises at least one circuit layer; the thinned area comprises a third electromagnetic shielding layer, a substrate layer, a second composite structure layer and a second electromagnetic shielding layer which are sequentially stacked; at the junction between the thinned area and the non-thinned area, an insulating material is arranged between the first composite structure layer and the third electromagnetic shielding layer, and the insulating material insulates the circuit layer in the first composite structure layer from the third electromagnetic shielding layer.

[0006] The embodiment of the present disclosure also provides a display device comprising the circuit board.

[0007] The circuit board of the embodiment of the present disclosure is provided with an insulating material at the junction of the thinning area and the non-thinning area. The insulating material isolates the third electromagnetic shielding layer of the thinning area from the circuit layer in the non-thinning area that is on the same layer as the circuit layer removed from the thinning area. In this way, at the junction of the thinning area and the non-thinning area, a short circuit problem caused by the connection between the third electromagnetic shielding layer in the thinning area and the circuit layer in the non-thinning area can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are intended to provide a further understanding of the technical solutions of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solutions of the present disclosure and do not constitute a limitation of the technical solutions of the present disclosure. The shapes and sizes of the components in the accompanying drawings do not reflect the actual scale and are intended only to illustrate the contents of the present disclosure.

[0009] Figure 1 is a schematic diagram of a portion of the structure of a circuit board of some exemplary embodiments;

[0010] Figure 2 For some technologies Figure 1 AA cross-sectional structural diagram;

[0011] Figure 3a In some exemplary embodiments Figure 1 AA cross-sectional structural diagram;

[0012] Figure 3b In some other exemplary embodiments Figure 1 AA cross-sectional structural diagram;

[0013] Figure 4 In some exemplary embodiments Figure 1 Schematic diagram of the BB cross-section structure. DETAILED DESCRIPTION

[0014] Those skilled in the art should understand that the technical solutions of the embodiments of the present disclosure may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and all should be included in the scope of the claims of the present disclosure.

[0015] like Figure 1 As shown, Figure 1For a schematic view of a partial structure of a circuit board of some example embodiments, the circuit board may, for example, include a main body portion 100, a binding portion 200, and an extension portion 300; the main body portion 100 may include opposite first and second side edges, the binding portion 200 may be disposed at the first side edge of the main body portion 100, and the extension portion 300 may be disposed at the second side edge of the main body portion 100; the binding portion 200 may be provided with a binding pad configured to be connected to a first external circuit in a binding manner, a length direction of the binding portion 200 may be parallel to an extension direction of the first side edge of the main body portion 100, the extension portion 300 may extend away from the main body portion 100, and an end of the extension portion 300 away from the main body portion 100 may be configured to be connected to a second external circuit. The main body portion 100 may be provided with an electronic component area 1021. In the present example, the main body portion 100, the binding portion 200, and the extension portion 300 are all substantially rectangular in shape, and in other embodiments, the main body portion 100, the binding portion 200, and the extension portion 300 may be designed to have other regular or irregular shapes according to actual requirements. In order to save the overall space of an electronic device, the main body portion 100 of the circuit board may be provided with a thinning area 101 for designing other components.

[0016] As shown in Figure 2 , Figure 2 For a schematic view of an A-A cross-sectional structure in some technologies, Figure 1 , the thinning area 101 of the circuit board may be attached to an electromagnetic shielding (EMI) film 1' after removing at least one copper layer (i.e., a circuit layer), and due to attachment precision and process problems, the EMI film 1' of the thinning area 101 may be connected to a copper layer 2' of a surrounding non-thinning area 102, causing a short circuit. In addition, due to the thickness difference between the thinning area 101 and the non-thinning area 102, the junction M' between the thinning area 101 and the non-thinning area 102 is not covered by the EMI film 1', causing electromagnetic leakage and electromagnetic interference, and during the bending process of the FPC, stress concentration may occur at the junction M' between the thinning area 101 and the non-thinning area 102, causing the problem of broken traces.

[0017] Embodiments of the present disclosure provide a circuit board, in some example embodiments, as shown in Figure 3a , Figure 3a For a schematic view of an A-A cross-sectional structure in some example embodiments, Figure 1A-A cross-sectional structural schematic diagram of the circuit board, the circuit board comprising a main body part 100, the main body part 100 comprising a thinned region 101 and a non-thinned region 102; the non-thinned region 102 comprising a first electromagnetic shielding layer 12, a first composite structure layer 11, a substrate layer 10, a second composite structure layer 21 and a second electromagnetic shielding layer 22 which are sequentially stacked; the second composite structure layer 21 comprising at least one circuit layer; the first composite structure layer 11 comprising at least one circuit layer; the thinned region 101 comprising a third electromagnetic shielding layer 13, a substrate layer 10, a second composite structure layer 21 and a second electromagnetic shielding layer 22 which are sequentially stacked; at the junction of the thinned region 101 and the non-thinned region 102, an insulating material 31 is provided between the first composite structure layer 11 and the third electromagnetic shielding layer 13, the insulating material 31 insulating the circuit layer in the first composite structure layer 11 from the third electromagnetic shielding layer 13.

[0018] In the circuit board of the present disclosure, the first composite structure layer 11 is completely removed in the thinned region 101, and at the junction of the thinned region 101 and the non-thinned region 102, an insulating material 31 is provided between the first composite structure layer 11 and the third electromagnetic shielding layer 13, the insulating material 31 insulating the circuit layer in the first composite structure layer 11 from the third electromagnetic shielding layer 13. In this way, at the junction of the thinned region 101 and the non-thinned region 102, the short circuit problem caused by the connection of the third electromagnetic shielding layer 13 of the thinned region 101 and the circuit layer of the first composite structure layer 11 of the non-thinned region 102 can be prevented.

[0019] In some example embodiments, the circuit board can be a flexible circuit board. The total number of circuit layers (also referred to as total number of layers) of the main body part can not be limited, and can be two, three, four or six, etc., and adjacent two circuit layers are separated by an insulating layer. The first composite structure layer and the second composite structure layer can each comprise one or more circuit layers. The substrate layer can be a base material layer for directly disposing a circuit layer, or can be an adhesive layer for adhesion; the material of the base material layer can be polyimide (PI) or polyethylene terephthalate (PET), etc. The material of the circuit layer can be copper.

[0020] In some example embodiments, as Figure 3aAs shown, the first composite structure layer 11 includes a fourth substructure layer 111 and a first cover layer 112 which are sequentially stacked on the substrate layer 10 in a direction away from the substrate layer 10, and the first electromagnetic shielding layer 12 is arranged on a surface of the first cover layer 112 away from the substrate layer 10; in a direction perpendicular to the substrate layer 10, the thickness of the insulating material 31 is d1, and the thickness of the fourth substructure layer 111 is d3, d1>d3. In this way, the insulating material 31 can completely isolate all the circuit layer(s) of the first composite structure layer 11 in the non-thinned region 102 from the third electromagnetic shielding layer 13 in the thinned region 101.

[0021] In some embodiments of the present embodiment, the fourth substructure layer 111 can include one or more circuit layers, and in the present example, one circuit layer is taken as an example for illustration. As shown, Figure 3a As shown, the circuit board is a double-layer circuit board, the total number of circuit layers of the main body part 100 is two, and the first composite structure layer 11 and the second composite structure layer 21 each include one circuit layer. The fourth substructure layer 111 is a first circuit layer. The second composite structure layer 21 can include a second circuit layer 211 arranged on the second surface of the substrate layer 10 and a second cover layer 212 arranged on a side of the second circuit layer 211 away from the substrate layer 10, and the second electromagnetic shielding layer 22 is arranged on a surface of the second cover layer 212 away from the substrate layer 10. In the thinned region 101, all the film layers of the first composite structure layer 11 are removed, and the thinned region 101 includes a third electromagnetic shielding layer 13, a substrate layer 10, a second composite structure layer 21 and a second electromagnetic shielding layer 22 which are sequentially stacked, and the third electromagnetic shielding layer 13 is arranged on the first surface of the substrate layer 10. At the junction of the thinned region 101 and the non-thinned region 102, the fourth substructure layer 111 and the third electromagnetic shielding layer 13 are separated by an insulating material 31, and the insulating material 31 separates the fourth substructure layer 111 and the third electromagnetic shielding layer 13. To ensure the isolation effect, the insulating material 31 is also partially arranged on an end surface of the first cover layer 112 facing the thinned region 101, i.e., in a direction perpendicular to the substrate layer 10, the thickness d1 of the insulating material 31 is greater than the thickness d3 of the fourth substructure layer 111.

[0022] Exemplarily, as shown, Figure 3aAs shown, the insulating material 31 can be an insulating glue. The material of the base layer 10 can be polyimide (PI) or polyethylene terephthalate (PET), etc., and the thickness of the base layer 10 can be 20 to 30 microns, such as 25 microns. The thickness of the fourth substructure layer 111 (first circuit layer) and the second circuit layer 211 can be approximately 15 to 25 microns, such as 20 microns. The thickness of the first covering layer 112 and the second covering layer 212 can be approximately 20 to 30 microns, such as 25 microns. The first covering layer 112 and the second covering layer 212 can each include a PI layer and an adhesive layer. The thickness of the first electromagnetic shielding layer 12, the third electromagnetic shielding layer 13, and the second electromagnetic shielding layer 22 can be approximately 10 to 15 microns, such as 12 microns.

[0023] In an example of this embodiment, Figure 3a As shown, at the junction of the thinned region 101 and the non-thinned region 102, the edge of the fourth substructure layer 111 can be set inward compared to the edges of the first cover layer 112 and the first electromagnetic shielding layer 12. In this way, at the junction of the thinned region 101 and the non-thinned region 102, the first cover layer 112 and the first electromagnetic shielding layer 12 can be ensured to completely cover the circuit layer in the fourth substructure layer 111, and a larger amount of insulating material 31 can be filled in the inward edge of the fourth substructure layer 111 to improve the insulation effect.

[0024] In an example of this embodiment, Figure 3a As shown, at the junction of the thinning area 101 and the non-thinning area 102 , the edges of the first covering layer 112 and the first electromagnetic shielding layer 12 may be flush with each other.

[0025] In some exemplary embodiments, Figure 3a As shown, at the boundary between the thinned region 101 and the non-thinned region 102, a conductive material 32 is provided on the end surface of the first composite structural layer 11 facing the thinned region 101. The conductive material 32 connects the first electromagnetic shielding layer 12 and the third electromagnetic shielding layer 13. This prevents electromagnetic wave leakage at the boundary between the thinned region 101 and the non-thinned region 102 due to the lack of electromagnetic shielding layer coverage.

[0026] In an example of this embodiment, Figure 3aAs shown, the surface of the first composite structure layer 11 in the non-thinning area 102 away from the base layer 10 protrudes from the surface of the third electromagnetic shielding layer 13 in the thinning area 101 away from the base layer 10; the portion of the first composite structure layer 11 in the non-thinning area 102 protruding from the surface of the third electromagnetic shielding layer 13 in the thinning area 101 away from the base layer 10 ( Figure 3a In the example, the end surface of the first covering layer 112 facing the thinned area 101 is completely covered by the conductive material 32. The conductive material 32 is also provided on the end surface of the first electromagnetic shielding layer 12 facing the thinned area 101, and on the surface of the third electromagnetic shielding layer 13 away from the base layer 10. In this way, the conductive material 32 can completely cover the location where electromagnetic waves may leak at the junction of the thinned area 101 and the non-thinned area 102, thereby improving the electromagnetic shielding effect.

[0027] The present disclosure also provides another exemplary embodiment of a circuit board, such as Figure 3b As shown, Figure 3b In some other exemplary embodiments Figure 1 AA cross-sectional structural diagram, the circuit board includes a main body 100, the main body 100 includes a thinning area 101 and a non-thinning area 102; the non-thinning area 102 includes a first electromagnetic shielding layer 12, a first composite structure layer 11, a base layer 10, a second composite structure layer 21, and a second electromagnetic shielding layer 22 stacked in sequence; the second composite structure layer 21 includes at least one circuit layer; the first composite structure layer 11 includes a first substructure layer 51 and a second substructure layer 52 stacked in sequence in a direction away from the base layer 10, and the first substructure layer 51 and the second substructure layer 52 each include at least one circuit layer;

[0028] The thinning area 101 includes a third electromagnetic shielding layer 13, a first substructure layer 51, a base layer 10, a second composite structure layer 21 and a second electromagnetic shielding layer 22 stacked in sequence; at the junction of the thinning area 101 and the non-thinning area 102, an insulating material 31 is provided between the second substructure layer 52 and the third electromagnetic shielding layer 13, and the insulating material 31 isolates the circuit layer in the second substructure layer 52 from the third electromagnetic shielding layer 13.

[0029] In the circuit board of the disclosed embodiment, the second substructure layer 52 in the first composite structural layer 11 is completely removed from the thinned region 101, leaving the first substructure layer 51 in the thinned region 101. At the boundary between the thinned region 101 and the non-thinned region 102, an insulating material 31 is provided between the second substructure layer 52 and the third electromagnetic shielding layer 13. The insulating material 31 isolates the circuit layer in the second substructure layer 52 from the third electromagnetic shielding layer 13. This prevents short circuits caused by the third electromagnetic shielding layer 13 in the thinned region 101 connecting to the circuit layer in the second substructure layer 52 in the non-thinned region 102 at the boundary between the thinned region 101 and the non-thinned region 102.

[0030] In some exemplary embodiments, Figure 3b As shown, the second substructure layer 52 includes a third substructure layer 521 and a first cover layer 522 stacked sequentially on the first substructure layer 51 in a direction away from the base layer 10. The first electromagnetic shielding layer 12 is disposed on the surface of the first cover layer 522 away from the base layer 10. In a direction perpendicular to the base layer 10, the thickness of the insulating material 31 is d1, and the thickness of the third substructure layer 521 is d2, with d1 > d2. In this way, the insulating material 31 can completely isolate all circuit layers (one or more) of the third substructure layer 521 in the non-thinned area 102 from the third electromagnetic shielding layer 13 in the thinned area 101.

[0031] In some implementations of this embodiment, the first substructure layer 51 and the second substructure layer 52 each include one or more circuit layers, and the third substructure layer 521 includes one or more circuit layers. In this example, the first substructure layer 51 and the second substructure layer 52 each include one circuit layer. Figure 3bAs shown, in the non-thinned region 102, the first sub-structure layer 51 comprises a first circuit layer 511 and an insulating layer 512 which are sequentially stacked on the base layer 10; the second sub-structure layer 52 comprises a third sub-structure layer (which can be a third circuit layer) 521 and a first cover layer 522 which are sequentially stacked on the insulating layer 512 in a direction away from the base layer 10, and the first electromagnetic shielding layer 12 is arranged on a surface of the first cover layer 522 away from the base layer 10. The second composite structure layer 21 can comprise a second circuit layer 211 arranged on a second surface of the base layer 10 and a second cover layer 212 arranged on a side of the second circuit layer 211 away from the base layer 10, and the second electromagnetic shielding layer 22 is arranged on a surface of the second cover layer 212 away from the base layer 10. The thinned region 101 comprises a third electromagnetic shielding layer 13, a first sub-structure layer 51, a base layer 10, a second composite structure layer 21 and a second electromagnetic shielding layer 22 which are sequentially stacked. At the junction of the thinned region 101 and the non-thinned region 102, an insulating material 31 is arranged between the second sub-structure layer 52 and the third electromagnetic shielding layer 13, and the insulating material 31 insulates the third sub-structure layer (which can be a third circuit layer) 521 from the third electromagnetic shielding layer 13. To ensure insulation effect, the insulating material 31 is also partially arranged on an end surface of the first cover layer 522 facing the thinned region 101, i.e. in a direction perpendicular to the base layer 10, the thickness d1 of the insulating material 31 is greater than the thickness d2 of the third sub-structure layer (which can be a third circuit layer) 521.

[0032] In one example of the embodiment, as shown in FIG. 1, the third sub-structure layer 521 comprises a third circuit layer 5211 and a third cover layer 5212 which are sequentially stacked in a direction away from the base layer 10. Figure 3b As shown, at the junction of the thinned region 101 and the non-thinned region 102, the edge of the third sub-structure layer 521 can be arranged inwardly relative to the edges of the first cover layer 522 and the first electromagnetic shielding layer 12. In this way, at the junction of the thinned region 101 and the non-thinned region 102, it can be ensured that the first cover layer 522 and the first electromagnetic shielding layer 12 completely cover the circuit layer in the third sub-structure layer 521, and more insulating material 31 can be filled at the inwardly recessed edge of the third sub-structure layer 521, thereby improving the insulation effect.

[0033] In one example of the embodiment, as shown in FIG. 1, the third sub-structure layer 521 comprises a third circuit layer 5211 and a third cover layer 5212 which are sequentially stacked in a direction away from the base layer 10. Figure 3b As shown, at the junction of the thinned region 101 and the non-thinned region 102, the edges of the first cover layer 522 and the first electromagnetic shielding layer 12 can be arranged flush.

[0034] In some example embodiments, as shown in FIG. 1, the third sub-structure layer 521 comprises a third circuit layer 5211 and a third cover layer 5212 which are sequentially stacked in a direction away from the base layer 10. Figure 3bAs shown, at the junction of the thinning region 101 and the non-thinning region 102, the end surface of the first composite structure layer 11 facing the thinning region 101 is provided with a conductive material 32, which connects the first electromagnetic shielding layer 12 and the third electromagnetic shielding layer 13. In this way, electromagnetic wave leakage at the junction of the thinning region 101 and the non-thinning region 102 due to the absence of electromagnetic shielding layer coverage can be avoided.

[0035] In one example of the embodiment, as shown in Figure 3b As shown, the surface of the first composite structure layer 11 of the non-thinning region 102 away from the base layer 10 protrudes from the surface of the third electromagnetic shielding layer 13 of the thinning region 101 away from the base layer 10; the portion of the surface of the first composite structure layer 11 of the non-thinning region 102 protruding from the surface of the third electromagnetic shielding layer 13 of the thinning region 101 away from the base layer 10 Figure 3b In one example, the end surface of the portion of the first composite structure layer 11 of the non-thinning region 102 protruding from the surface of the third electromagnetic shielding layer 13 of the thinning region 101 away from the base layer 10 is completely covered by the conductive material 32, which is also provided on the end surface of the first electromagnetic shielding layer 12 facing the thinning region 101 and on the surface of the third electromagnetic shielding layer 13 away from the base layer 10. In this way, it can be ensured that at the junction of the thinning region 101 and the non-thinning region 102, the conductive material 32 can completely cover the position where electromagnetic waves may leak, improving the electromagnetic shielding effect.

[0036] In some example embodiments, as shown in Figure 3a , Figure 3b The conductive material 32 can be an elastically deformable conductive material 32, which can be conductive glue. When the circuit board is a flexible circuit board and is bent, due to the thickness difference between the thinning region 101 and the non-thinning region 102, stress concentration occurs at the junction of the thinning region 101 and the non-thinning region 102, causing the traces of the circuit layer to break. By providing the conductive material 32 as elastically deformable, the conductive material 32 can act as a buffer during the bending of the flexible circuit board, relieving the stress on the traces at the junction of the thinning region 101 and the non-thinning region 102, thereby reducing the breaking of the traces.

[0037] In some example embodiments, as shown in Figure 1 and Figure 3aAs shown, the main body 100 can include opposite first and second side edges, and the circuit board can further include a binding portion 200 disposed at the first side edge of the main body 100 and an extension portion 300 disposed at the second side edge of the main body 100. The binding portion 200 is provided with a binding pad 201 configured to be connected with a first external circuit in a binding manner, and the length direction of the binding portion 200 can be parallel to the extension direction of the first side edge of the main body 100; the extension portion 300 extends away from the main body 100, and one end of the extension portion 300 away from the main body 100 can be configured to be connected with a second external circuit. In the present example, the shapes of the main body 100, the binding portion 200 and the extension portion 300 are all substantially rectangular, and in other embodiments, the shapes of the main body 100, the binding portion 200 and the extension portion 300 can be designed as other regular or irregular shapes according to actual needs.

[0038] The main body 100 is provided with a thinned region 101, and the non-thinned region 102 can surround the thinned region 101, and the area of the orthographic projection of the non-thinned region 102 on the base layer 10 is greater than the area of the orthographic projection of the thinned region 101 on the base layer 10. The shape of the thinned region 101 can be rectangular, trapezoidal, etc., and the shape of the thinned region 101 can be set as needed. The non-thinned region 102 is provided with at least one electronic component region 1021.

[0039] In one example of the present embodiment, as Figure 1 and Figure 4 shown, Figure 4 the B-B cross-sectional structure schematic diagram of Figure 1 in some example embodiments, Figure 4 the B-B cross-sectional structure schematic diagram and Figure 3a the A-A cross-sectional structure schematic diagram can be different cross-sectional structure schematic diagrams of the circuit board of the same embodiment, and the first electromagnetic shielding layer 12, the first composite structure layer 11, the base layer 10, the second composite structure layer 21 and the second electromagnetic shielding layer 22 of the main body 100 can all extend to the extension portion 300. The number of circuit layers of the extension portion 300 can be the same as the number of circuit layers of the main body 100. In other embodiments, the number of circuit layers of the extension portion 300 can be less than the number of circuit layers of the main body 100.

[0040] In some example embodiments, as Figure 3aAs shown, the binding pad 201 can include a first sub-pad portion and a second sub-pad portion 2011 stacked, the material of the first sub-pad portion being different from that of the second sub-pad portion 2011; at least one circuit layer in the substrate layer 10 and the second composite structure layer 21 extends to the binding portion 200, the first sub-pad portion being provided on the side of the binding portion 200 away from the substrate layer 10, and the second sub-pad portion 2011 being located on the side of the first sub-pad portion away from the substrate layer 10.

[0041] Exemplarily, the material of the first sub-pad portion can be the same as that of the circuit layer (such as copper) on which the first sub-pad portion is located. The second sub-pad portion 2011 can be a single-layer structure or a multi-layer structure, for example, the second sub-pad portion 2011 can include a nickel layer and a gold layer stacked on the first sub-pad portion in sequence, the thickness of the nickel layer can be 2-4 microns, and the thickness of the gold layer can be 0.03-0.1 microns (such as 0.05 microns). The nickel layer can improve the welding performance of the binding pad 201, and the gold layer can protect the nickel layer from oxidation or corrosion. The nickel layer and the gold layer can be formed by an electroless nickel immersion gold (ENIG) process or an electroplated nickel gold process.

[0042] Exemplarily, as shown, Figure 3a As shown, the surface of the binding pad 201 away from the substrate layer 10 is lower than the surface of the second composite structure layer 21 of the main body portion 100 away from the substrate layer 10, and a gap can be provided between the end surface of the film layer in the second composite structure layer 21 of the main body portion 100 not extending to the binding portion 200 and the second sub-pad portion 2011, and the gap can be filled with a protective glue 41. In actual application, the circuit board can be a flexible circuit board, and after the binding portion 200 is bent, due to the difference in thickness between the binding portion 200 and the main body portion 100, the flexible circuit board is prone to stress concentration at the junction of the binding portion 200 and the main body portion 100, causing internal wiring to break. The protective glue 41 can play a role in buffering stress and preventing wiring from breaking.

[0043] In some exemplary embodiments, as shown, Figure 3aAs shown, at least one circuit layer in the substrate layer 10 and the second composite structure layer 21 extends to the binding portion 200, the binding pads 201 and the third electromagnetic shielding layer 13 of the thinning area 101 are located on both sides of the substrate layer 10; the surface of the second electromagnetic shielding layer 22 away from the substrate layer 10 can be provided with an adhesive layer 23, and the surface of the adhesive layer 23 away from the substrate layer 10 is provided with a protective film 24 which can be peeled off. Exemplarily, the thickness of the adhesive layer 23 and the protective film 24 can be about 0.05 mm. In the embodiment, when the circuit board is actually applied, the protective film 24 can be peeled off, and the circuit board can be fixed in the whole machine through the adhesive layer 23.

[0044] In some exemplary embodiments, as shown in Figure 1 and Figure 3a As shown, the non-thinning area 102 is provided with at least one electronic component area 1021, the electronic component area 1021 is provided with an electronic component 33, and the surface of at least one electronic component area 1021 away from the electronic component 33 is provided with a reinforcing sheet 42. The reinforcing sheet 42 can play a role of supporting and strengthening the local mechanical strength of the circuit board, and facilitates the installation of the electronic component 33. The reinforcing sheet 42 can be a stainless steel sheet or the like. The surface of the reinforcing sheet 42 away from the substrate layer 10 can be provided with the adhesive layer 23 and the protective film 24.

[0045] In some exemplary embodiments, as shown in Figure 1 As shown, the non-thinning area 102 can be provided with a windowed area 1022, and the ground circuit in the first composite structure layer 11 of the windowed area 1022 is at least partially exposed. In this way, when the circuit board is applied to the whole machine (such as a mobile phone), the ground circuit can be connected with the shell of the whole machine, so as to realize the grounding of the circuit board.

[0046] The embodiment of the present disclosure further provides a display device comprising the circuit board described in any of the foregoing embodiments. Exemplarily, the display device further comprises a display panel, and the circuit board can be connected with the display panel in a binding mode. The circuit board can be a flexible circuit board, which is connected with the display panel in a binding mode through the binding portion, is bent to the back of the display panel, and can be connected with a master control board in the whole machine through the extension portion. The display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, or the like.

[0047] In the drawings, the size, the thickness or the region of each constituent may, at times, be exaggerated for the purpose of making the present disclosure clear. Thus, the embodiments of the present disclosure are not necessarily limited to such a scale. Furthermore, the drawings schematically show some examples, and the embodiments of the present disclosure are not limited to the shapes or the values shown in the drawings.

[0048] In the description herein, "parallel" refers to a state in which two straight lines form an angle of -10° or more and 10° or less, and thus includes a state in which the angle is -5° or more and 5° or less. In addition, "perpendicular" refers to a state in which two straight lines form an angle of 80° or more and 100° or less, and thus includes a state in which the angle is 85° or more and 95° or less.

[0049] In the description herein, the terms "upper", "lower", "left", "right", "top", "inner", "outer", "axial", "quadrangle", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the convenience of a simplified description of the embodiments of the present disclosure, and do not indicate or imply that the structure referred to has a particular orientation, is constructed and operated in a particular orientation, and thus cannot be understood as a limitation on the present disclosure.

[0050] In the description herein, unless explicitly specified and limited otherwise, the terms "connection", "fixed connection", "mounting", and "assembly" should be understood broadly, for example, can be fixed connection, or detachable connection, or integrally connected; the terms "mounting", "connection", and "fixed connection" can be directly connected, or indirectly connected through an intermediate medium, or communication inside two elements. For those of ordinary skill in the art, the meaning of the above terms in the embodiments of the present disclosure can be understood according to the circumstances.

Claims

1. A circuit board, characterized in that: The main body includes a thinning area and a non-thinning area; the non-thinning area includes a first electromagnetic shielding layer, a first composite structure layer, a base layer, a second composite structure layer, and a second electromagnetic shielding layer stacked in sequence; the second composite structure layer includes at least one circuit layer; The first composite structure layer includes a first substructure layer and a second substructure layer stacked in sequence in a direction away from the base layer, and the first substructure layer and the second substructure layer each include at least one circuit layer; the thinning area includes a third electromagnetic shielding layer, a first substructure layer, a base layer, a second composite structure layer, and a second electromagnetic shielding layer stacked in sequence; in a plane perpendicular to the base layer, the circuit layer in the second substructure layer and the third electromagnetic shielding layer are spaced apart from each other; at the junction of the thinning area and the non-thinning area, an insulating material is provided between the second substructure layer and the third electromagnetic shielding layer, and the insulating material fills the space between the circuit layer in the second substructure layer and the third electromagnetic shielding layer, thereby isolating the circuit layer in the second substructure layer from the third electromagnetic shielding layer; Alternatively, the first composite structure layer includes at least one circuit layer; the thinning area includes a third electromagnetic shielding layer, a base layer, a second composite structure layer and a second electromagnetic shielding layer stacked in sequence; in a plane perpendicular to the base layer, the circuit layer in the first composite structure layer and the third electromagnetic shielding layer are spaced apart from each other; at the junction of the thinning area and the non-thinning area, an insulating material is provided between the first composite structure layer and the third electromagnetic shielding layer, and the insulating material fills the gap between the circuit layer in the first composite structure layer and the third electromagnetic shielding layer, isolating the circuit layer in the first composite structure layer from the third electromagnetic shielding layer.

2. The circuit board according to claim 1, wherein: The second substructure layer includes a third substructure layer and a first covering layer sequentially stacked on the first substructure layer in a direction away from the base layer, and the first electromagnetic shielding layer is arranged on a surface of the first covering layer away from the base layer; In a direction perpendicular to the base layer, the thickness of the insulating material is d1, the thickness of the third substructure layer is d2, and d1>d2.

3. The circuit board according to claim 1, wherein: The thinning area includes a third electromagnetic shielding layer, a base layer, a second composite structure layer and a second electromagnetic shielding layer stacked in sequence; The first composite structure layer includes a fourth substructure layer and a first covering layer sequentially stacked on the base layer in a direction away from the base layer, and the first electromagnetic shielding layer is arranged on a surface of the first covering layer away from the base layer; In a direction perpendicular to the base layer, the thickness of the insulating material is d1, the thickness of the fourth substructure layer is d3, and d1>d3.

4. The circuit board according to claim 2, wherein: At the junction of the thinned area and the non-thinned area, an edge of the third substructure layer is retracted compared to edges of the first covering layer and the first electromagnetic shielding layer.

5. The circuit board according to claim 3, wherein: At the junction of the thinned area and the non-thinned area, the edge of the fourth substructure layer is retracted compared to the edges of the first covering layer and the first electromagnetic shielding layer.

6. The circuit board according to claim 4 or 5, wherein: At the junction of the thinned area and the non-thinned area, edges of the first covering layer and the first electromagnetic shielding layer are flush with each other.

7. The circuit board according to claim 1, wherein: At the junction of the thinning area and the non-thinning area, a conductive material is provided on the end surface of the first composite structure layer facing the thinning area, and the conductive material connects the first electromagnetic shielding layer and the third electromagnetic shielding layer.

8. The circuit board according to claim 7, wherein: The surface of the first composite structure layer in the non-thinning area away from the base layer protrudes beyond the surface of the third electromagnetic shielding layer in the thinning area away from the base layer; The end surface of the first composite structural layer in the non-thinning zone, which protrudes from the surface of the third electromagnetic shielding layer in the thinning zone and is away from the base layer, facing the thinning zone is completely covered by the conductive material, and the conductive material is also arranged on the end surface of the first electromagnetic shielding layer facing the thinning zone and on the surface of the third electromagnetic shielding layer away from the base layer.

9. The circuit board according to claim 7, wherein: The conductive material is an elastically deformable conductive material.

10. The circuit board according to claim 1, wherein: The non-thinning area surrounds the thinning area, and an orthographic projection area of ​​the non-thinning area on the base layer is larger than an orthographic projection area of ​​the thinning area on the base layer.

11. The circuit board according to claim 1, wherein: The main body includes a first side and a second side opposite to each other, and the circuit board further includes a binding portion provided at the first side of the main body and an extending portion provided at the second side of the main body; The binding portion is provided with a binding pad configured to be bound and connected to an external circuit. The length direction of the binding portion is parallel to the extension direction of the first side of the main body portion. The extension portion extends in a direction away from the main body portion.

12. The circuit board according to claim 11, wherein: The binding pad includes a first sub-pad portion and a second sub-pad portion stacked together, wherein the material of the first sub-pad portion is different from the material of the second sub-pad portion; At least one circuit layer in the base layer and the second composite structure layer extends to the binding part, and a circuit layer of the binding part away from the base layer is provided with the first sub-pad part, and the second sub-pad part is located on a side of the first sub-pad part away from the base layer.

13. The circuit board according to claim 12, wherein: The surface of the binding pad away from the base layer is lower than the surface of the second composite structure layer of the main body away from the base layer, and a gap is provided between the end surface of the membrane layer of the second composite structure layer of the main body that does not extend to the binding part and the second sub-pad part, and the gap is filled with protective glue.

14. The circuit board according to claim 11, wherein: At least one circuit layer in the base layer and the second composite structure layer extends to the binding portion, and the binding pad and the third electromagnetic shielding layer are located on both sides of the base layer; An adhesive layer is provided on the surface of the second electromagnetic shielding layer away from the base layer, and a removable protective film is provided on the surface of the adhesive layer away from the base layer.

15. The circuit board according to claim 1, wherein: The non-thinning area is provided with at least one electronic component area, the electronic component area is provided with electronic components, and a reinforcing sheet is provided on a surface of at least one electronic component area that is away from the electronic components.

16. The circuit board according to claim 1, wherein The non-thinning area is provided with a window area, and the grounding line in the first composite structure layer in the window area is at least partially exposed.

17. A display device, characterized in that: A circuit board comprising the circuit board according to any one of claims 1 to 16.

Images