Flexible circuit board

Abstract

The utility model provides a flexible circuit board, the flexible circuit board comprises a flexible circuit board body and an electromagnetic wave shielding film, the electromagnetic wave shielding film comprises a protection layer, an electromagnetic absorption layer and an electromagnetic receiving layer, the electromagnetic receiving layer is bonded on the flexible circuit board body, the electromagnetic absorption layer is bonded on the upper side of the electromagnetic receiving layer, and the electromagnetic absorption layer is bonded on the lower side of the electromagnetic receiving layer. The protection layer is adhered to the upper side of the electromagnetic absorption layer, the electromagnetic receiving layer is used for receiving electromagnetic signals radiated by a circuit on the flexible circuit board, and the electromagnetic absorption layer absorbs and exports the electromagnetic signals received by the electromagnetic receiving layer; therefore, a stronger electromagnetic shielding effect can be realized through the electromagnetic wave shielding film, so that the electromagnetic wave shielding film can still ensure an absorption effect on electromagnetic signals radiated by a circuit of the flexible circuit board body after the thickness is reduced, and the production of a light and thin flexible circuit board with stable performance is facilitated; therefore, the flexible circuit board is lighter and thinner on the basis of ensuring good performance.

Description

Technical Field

[0001] The present disclosure relates to the technical field of circuit boards, and in particular to a flexible circuit board. Background Art

[0002] In order to ensure that the performance of the flexible circuit board will not be affected by hardness, the overall thickness of the existing flexible circuit board is usually large, which makes the flexible circuit board relatively hard and not soft enough, resulting in difficulty in bending the flexible circuit board and easy to crack or break. Therefore, it is necessary to design a new type of flexible circuit board so that the flexible circuit board can be thinner and easier to bend while ensuring good performance. Utility Model Content

[0003] The present disclosure provides a flexible circuit board to at least solve the above-mentioned problems in the prior art.

[0004] To achieve the above objectives, the present disclosure provides the following technical solutions: a flexible circuit board, comprising:

[0005] Flexible circuit board body;

[0006] The electromagnetic wave shielding film comprises a protective layer, an electromagnetic absorption layer and an electromagnetic receiving layer, wherein the electromagnetic receiving layer is bonded to the flexible circuit board body, the electromagnetic absorption layer is bonded to the upper side of the electromagnetic receiving layer, and the protective layer is bonded to the upper side of the electromagnetic absorption layer; wherein,

[0007] The electromagnetic receiving layer is used to receive the electromagnetic signal radiated by the circuit on the flexible circuit board, and the electromagnetic absorbing layer absorbs and derives the electromagnetic signal received by the electromagnetic receiving layer.

[0008] In one possible implementation manner, the protective layer is a transfer film, and the thickness of the protective layer is greater than 45 um and less than 55 um.

[0009] In one embodiment, the electromagnetic absorption layer includes:

[0010] A copper absorption layer is disposed on the upper side of the electromagnetic receiving layer, and is used to absorb and conduct electromagnetic signals. The thickness of the copper absorption layer is greater than 1um and less than 3um.

[0011] The insulating layer is arranged on the upper side of the copper absorption layer and the lower side of the protective layer, and the thickness of the insulating layer is greater than 4um and less than 8um.

[0012] In one possible implementation manner, the electromagnetic receiving layer is an anisotropic conductive adhesive layer, and the thickness of the electromagnetic receiving layer is greater than 7 um and less than 12 um.

[0013] In one possible implementation, the flexible circuit board body includes:

[0014] A first substrate layer is disposed on the lower side of the electromagnetic receiving layer;

[0015] The second substrate layer is bonded to the lower side of the first substrate layer.

[0016] In one embodiment, the first substrate layer includes:

[0017] a first substrate body;

[0018] A first upper conductive plating layer, electroplated on the upper side of the first substrate body;

[0019] A first lower conductive plating layer, electroplated on the lower side of the first substrate body;

[0020] The first covering layer is bonded to the upper side of the first upper conductive plating layer.

[0021] In one embodiment, the second substrate layer includes:

[0022] A second substrate body bonded to the lower side of the first lower conductive coating;

[0023] a second conductive plating layer, electroplated on the lower side of the second substrate body;

[0024] The second covering layer is bonded to the lower side of the second conductive plating layer.

[0025] In one possible implementation manner, the first upper conductive coating, the first lower conductive coating, and the second conductive coating are all grid structures.

[0026] In one embodiment, the first upper conductive plating layer, the first lower conductive plating layer and the second conductive plating layer are all formed of copper plating material.

[0027] In one possible implementation manner, a mesh size of a grid of one or more of the first upper conductive plating layer, the first lower conductive plating layer, and the second conductive plating layer is set to 0.1 mm*0.6 mm.

[0028] In the above-mentioned flexible circuit board, the electromagnetic signal radiated by the circuit of the flexible circuit board body is first received by the electromagnetic receiving layer, and then the electromagnetic signal received by the electromagnetic receiving layer is absorbed by the electromagnetic absorption layer, and the electromagnetic signal is exported so that the electromagnetic signal can flow back to the ground for absorption, thereby making the electromagnetic wave shielding film have a better shielding effect on electromagnetic waves; in this way, a stronger electromagnetic shielding effect can be achieved through the electromagnetic wave shielding film, so that the electromagnetic wave shielding film can still ensure the absorption effect of the electromagnetic signal radiated by the circuit of the flexible circuit board body after reducing the thickness, which is conducive to the production of a lighter and more stable flexible circuit board, thereby achieving a lighter and thinner flexible circuit board while ensuring good performance.

[0029] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, in which:

[0031] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0032] Figure 1 A schematic diagram of the structure of a flexible circuit board in an embodiment of the present disclosure is shown;

[0033] Figure 2 A cross-sectional view of the flexible circuit board along the II-II direction in an embodiment of the present disclosure is shown.

[0034] Description of the numbers in the figure:

[0035] In the figure: 11, flexible circuit board body, 111, first substrate layer, 1111, first substrate body, 1112, first upper conductive coating, 1113, first lower conductive coating, 1114, first covering layer, 112, second substrate layer, 1121, second substrate body, 1122, second conductive coating, 1123, second covering layer, 12, electromagnetic wave shielding film, 121, protective layer, 122, electromagnetic absorption layer, 1221, copper absorption layer, 1222, insulating layer, 123, electromagnetic receiving layer. DETAILED DESCRIPTION

[0036] In order to make the purpose, features, and advantages of the present disclosure more obvious and easy to understand, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0037] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of this disclosure can be achieved, and this document is not limited here.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] Please also read Figure 1 and Figure 2 The flexible circuit board includes a flexible circuit board body 11 and an electromagnetic wave shielding film 12. The electromagnetic wave shielding film 12 includes a protective layer 121, an electromagnetic absorption layer 122 and an electromagnetic receiving layer 123. The electromagnetic receiving layer 123 is bonded to the flexible circuit board body 11, the electromagnetic absorption layer 122 is bonded to the upper side of the electromagnetic receiving layer 123, the protective layer 121 is bonded to the upper side of the electromagnetic absorption layer 122, the electromagnetic receiving layer 123 is used to receive the electromagnetic signal radiated by the line on the flexible circuit board, and the electromagnetic absorption layer 122 absorbs and derives the electromagnetic signal received by the electromagnetic receiving layer 123.

[0040] In the above-mentioned flexible circuit board, the electromagnetic signal radiated by the circuit of the flexible circuit board body 11 is first received by the electromagnetic receiving layer 123, and then the electromagnetic signal received by the electromagnetic receiving layer 123 is absorbed by the electromagnetic absorption layer 122, and the electromagnetic signal is exported so that the electromagnetic signal can flow back to the ground for absorption, thereby making the electromagnetic wave shielding film 12 have a better shielding effect on electromagnetic waves; in this way, a stronger electromagnetic shielding effect can be achieved through the electromagnetic wave shielding film 12, so that the electromagnetic wave shielding film 12 can still ensure the absorption effect of the electromagnetic signal radiated by the circuit of the flexible circuit board body 11 after reducing the thickness, which is conducive to the production of a thinner and more stable flexible circuit board, thereby achieving a thinner and more lightweight flexible circuit board while ensuring good performance.

[0041] It is understandable that the better the flexibility of the flexible circuit board, the easier it is to bend and the less likely it is to crack or break, which is beneficial to increasing the service life of the flexible circuit board.

[0042] See also Figure 2 In some embodiments, the protective layer 121 is a transfer film to protect the entire flexible circuit board, for example, from being waterproof and moisture-proof, and the thickness of the protective layer 121 is greater than 45um and less than 55um; specifically, the thickness of the transfer film is 50um, so as to reduce the overall thickness of the electromagnetic wave shielding film 12, thereby improving the flexibility of the flexible circuit board.

[0043] In some embodiments, the electromagnetic absorption layer 122 includes a copper absorption layer 1221 and an insulating layer 1222. The copper absorption layer 1221 is arranged on the upper side of the electromagnetic receiving layer 123 to absorb and conduct electromagnetic signals. The insulating layer 1222 is arranged on the upper side of the copper absorption layer 1221 and the lower side of the protective layer 121 to isolate electromagnetic signals. The thickness of the copper absorption layer 1221 is greater than 1um and less than 3um, so as to reduce the thickness of the copper absorption layer 1221 while ensuring that the tube absorption layer has good absorption of electromagnetic signals. The thickness of the insulating layer 1222 is greater than 4um and less than 8um, so as to reduce the thickness of the insulating layer 1222 while ensuring that the insulating layer 1222 isolates electromagnetic signals.

[0044] Specifically, the thickness of the insulating layer 1222 is 6 um, and the thickness of the copper absorption layer 1221 is 2 um.

[0045] In some embodiments, the electromagnetic receiving layer 123 is an anisotropic conductive adhesive layer for receiving interference signals radiated from the line. The thickness of the electromagnetic receiving layer 123 is greater than 7um and less than 12um, so as to reduce the thickness of the electromagnetic receiving layer 123 while ensuring the effect of the electromagnetic receiving layer 123.

[0046] Specifically, the thickness of the electromagnetic receiving layer 123 is 9 um.

[0047] See also Figure 2 In some embodiments, the flexible circuit board body 11 includes a first substrate layer 111, the first substrate layer 111 is disposed on the lower side of the electromagnetic receiving layer 123, the first substrate layer 111 includes a first substrate body 1111, a first upper conductive plating layer 1112 and a first covering layer 1113, the first upper conductive plating layer 1112 is electroplated on the upper side of the first substrate body 1111, the first lower conductive plating layer 1113 is electroplated on the lower side of the first substrate body 1111, and the first covering layer 1113 is bonded to the upper side of the first upper conductive plating layer 1112;

[0048] The flexible circuit board body 11 also includes a second substrate layer 112, which is bonded to the lower side of the first substrate layer 111. The second substrate layer 112 includes a second substrate body 1121, a second conductive coating 1122 and a second covering layer 1123. The second substrate body 1121 is bonded to the lower side of the first lower conductive coating 1113, the second conductive coating 1122 is electroplated on the lower side of the second substrate body 1121, and the second covering layer 1123 is bonded to the lower side of the second conductive coating 1122.

[0049] In this way, a double-layer flexible circuit board is formed by the first substrate layer 111 and the second substrate layer 112 and a three-layer circuit layout can be realized, so that the circuit layout is more flexible, thereby realizing interconnection between various types of circuits, and the circuit layout is more compact, and a higher density circuit layout can be realized.

[0050] In this embodiment, the first substrate layer 111 and the second substrate layer 112 are bonded together by adhesive.

[0051] In some embodiments, the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 are all formed of copper plating material. Copper plating has good conductivity and low cost, so as to improve the conductive stability of the flexible circuit board.

[0052] In some embodiments, the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 are all grid structures; further, the mesh size of one or more of the grids in the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 is set to 0.1mm*0.6mm, that is, the mesh is a rectangular structure, the length of the mesh is 0.6mm, and the width of the mesh is 0.1mm.

[0053] In this way, by setting the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 as a grid structure, the flexible circuit board can be bent more easily, thereby reducing the risk of the flexible circuit board being cracked or broken. At the same time, by designing the mesh size of the grid of any one, any two or all of the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 to a larger size of 0.1mm*0.6mm, the flexibility of the flexible circuit board can be further improved, thereby further reducing the risk of the flexible circuit board being cracked or broken.

[0054] The working principle of the above-mentioned flexible circuit board is roughly as follows:

[0055] By improving the electromagnetic wave shielding film 12, the electromagnetic wave shielding film 12 can achieve a stronger electromagnetic shielding effect, so that the electromagnetic wave shielding film 12 can still ensure the absorption effect of the electromagnetic signal radiated by the circuit of the flexible circuit board body 11 after reducing the thickness, thereby improving the flexibility of the flexible circuit board;

[0056] By further optimizing the thickness of the flexible circuit board body 11, the bending resistance of the flexible circuit board is reduced, and the flexibility of the flexible circuit board is further improved;

[0057] Finally, by designing the mesh size of any one, any two or all of the first upper conductive coating 1112, the first lower conductive coating 1113 and the second conductive coating 1122 to be larger 0.1mm*0.6mm, the flexibility of the flexible circuit board is further improved, thereby reducing the risk of cracking or breaking of the flexible circuit board.

[0058] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A flexible circuit board, characterized in that: include: Flexible circuit board body; The electromagnetic wave shielding film comprises a protective layer, an electromagnetic absorption layer and an electromagnetic receiving layer, wherein the electromagnetic receiving layer is bonded to the flexible circuit board body, the electromagnetic absorption layer is bonded to the upper side of the electromagnetic receiving layer, and the protective layer is bonded to the upper side of the electromagnetic absorption layer; wherein, The electromagnetic receiving layer is used to receive the electromagnetic signal radiated by the circuit on the flexible circuit board, and the electromagnetic absorbing layer absorbs and derives the electromagnetic signal received by the electromagnetic receiving layer.

2. The flexible circuit board according to claim 1, characterized in that: The protective layer is a transfer film, and the thickness of the protective layer is greater than 45um and less than 55um.

3. The flexible circuit board according to claim 1, characterized in that: The electromagnetic absorption layer comprises: A copper absorption layer is disposed on the upper side of the electromagnetic receiving layer, and is used to absorb and conduct electromagnetic signals. The thickness of the copper absorption layer is greater than 1um and less than 3um. The insulating layer is arranged on the upper side of the copper absorption layer and the lower side of the protective layer, and the thickness of the insulating layer is greater than 4um and less than 8um.

4. The flexible circuit board according to claim 1, characterized in that: The electromagnetic receiving layer is an anisotropic conductive adhesive layer, and the thickness of the electromagnetic receiving layer is greater than 7um and less than 12um.

5. The flexible circuit board according to claim 1, characterized in that: The flexible circuit board body comprises: A first substrate layer is disposed on the lower side of the electromagnetic receiving layer; The second substrate layer is bonded to the lower side of the first substrate layer.

6. The flexible circuit board according to claim 5, characterized in that: The first substrate layer comprises: a first substrate body; A first upper conductive plating layer, electroplated on the upper side of the first substrate body; A first lower conductive plating layer, electroplated on the lower side of the first substrate body; The first covering layer is bonded to the upper side of the first upper conductive plating layer.

7. The flexible circuit board according to claim 6, characterized in that: The second substrate layer comprises: A second substrate body bonded to the lower side of the first lower conductive coating; a second conductive plating layer, electroplated on the lower side of the second substrate body; The second covering layer is bonded to the lower side of the second conductive plating layer.

8. The flexible circuit board according to claim 7, characterized in that: The first upper conductive plating layer, the first lower conductive plating layer and the second conductive plating layer are all grid structures.

9. The flexible circuit board according to claim 7, characterized in that: The first upper conductive plating layer, the first lower conductive plating layer and the second conductive plating layer are all formed of copper plating material.

10. The flexible circuit board according to claim 7, characterized in that: The mesh size of the grid of one or more of the first upper conductive plating layer, the first lower conductive plating layer and the second conductive plating layer is set to 0.1 mm*0.6 mm.

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