Flexible circuit board and intelligent terminal

Abstract

The utility model discloses a flexible circuit board and an intelligent terminal, the flexible circuit board comprises at least two conductive layers and insulating layers, the at least two conductive layers and the insulating layers are laminated along the thickness direction of the flexible circuit board, and at least one insulating layer is distributed between any two adjacent conductive layers; the material of the insulating layer adjacent to at least one conductive layer is different from the material of the remaining insulating layers. According to the flexible circuit board, various different signals can be transmitted at the same time, and the integration level of the circuit board is improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to a flexible circuit board and a smart terminal. Background Technology

[0002] With the trend towards thinner, lighter, and more multifunctional smart terminals, flexible circuit boards are being widely used due to their excellent flexibility and electrical performance.

[0003] In conceiving and implementing this application, the inventors discovered at least the following problems: As the integration level of circuits continues to increase, the same flexible circuit board can transmit signals of different frequency bands. However, due to the multi-layered structure of the flexible circuit board, signals of different frequency bands are prone to mutual interference during transmission, resulting in decreased signal transmission stability. Some solutions employ different circuit boards to transmit signals of different frequency bands to improve signal transmission stability. However, this increases the cost of the flexible circuit board.

[0004] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Utility Model Content

[0005] To address the aforementioned technical problems, this application provides a flexible circuit board and a smart terminal, which can improve the stability of signal transmission, reduce the cost of the flexible circuit board, and increase the utilization rate of the flexible circuit board.

[0006] In a first aspect, this application provides a flexible circuit board, comprising:

[0007] At least two conductive layers and an insulating layer are stacked along the thickness direction of the flexible circuit board, and at least one insulating layer is distributed between any two adjacent conductive layers.

[0008] The material of the insulating layer adjacent to at least one of the conductive layers is different from the material of the remaining insulating layers.

[0009] In some embodiments, the insulating layer includes at least two first insulating layers and at least two second insulating layers, wherein the first insulating layers and the second insulating layers are spaced apart along the thickness direction of the flexible circuit board;

[0010] The dielectric constant of the first insulating layer is greater than that of the second insulating layer.

[0011] In some embodiments, the conductive layer includes a first conductive layer and a second conductive layer, wherein the first conductive layer is disposed between two adjacent first insulating layers and the second conductive layer is disposed between two adjacent second insulating layers.

[0012] In some embodiments, the first insulating layer comprises at least one of a modified polyimide layer and a liquid crystal polymer layer; and / or, the second insulating layer comprises a polyimide layer.

[0013] In some embodiments, the first conductive layer and the first insulating layers on both sides together form a first signal transmission channel, the second conductive layer and the second insulating layers on both sides together form a second signal transmission channel, and a second connecting layer is provided between the first signal transmission channel and the second signal transmission channel.

[0014] In some implementations, the first signal transmission channel is at least one, and the second signal transmission channel is at least two.

[0015] At least two second signal transmission channels and at least one first signal transmission channel are alternately stacked along the thickness direction of the flexible circuit board.

[0016] In some implementations, the transmission bandwidth of the first signal transmission channel is greater than the transmission bandwidth of the second signal transmission channel; and / or, the first signal transmission channel is a radio frequency signal channel and the second signal transmission channel is a baseband signal channel.

[0017] In some embodiments, a first connecting layer is provided between at least one of the conductive layers and at least one of the adjacent insulating layers.

[0018] Secondly, this application provides a smart terminal, including a flexible circuit board as described in any one of the first aspects.

[0019] In some embodiments, the smart terminal further includes a power supply device; the flexible circuit board and the power supply device are electrically connected.

[0020] The flexible circuit board and smart terminal provided in this application include: the flexible circuit board comprising at least two conductive layers and multiple insulating layers, wherein the at least two conductive layers and multiple insulating layers are stacked along the thickness direction of the flexible circuit board, and at least one insulating layer is distributed between any two adjacent conductive layers; wherein the material of the insulating layer adjacent to at least one conductive layer is different from the material of the other insulating layers. Such a flexible circuit board can transmit multiple different signals simultaneously, improving the integration of the circuit board. By using different materials for the insulating layers, mutual interference between different signals is avoided, improving the stability and integrity of signal transmission on the flexible circuit board. Simultaneously, it can also improve the utilization rate of the flexible circuit board and reduce its material cost.

[0021] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the light-emitting module and smart terminal provided by the embodiments of this application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0023] Figure 1 A schematic diagram of a flexible circuit board provided in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of a smart terminal provided in an embodiment of this application.

[0025] The realization of the objectives, functional features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0027] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Optionally, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which needs to be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0028] It should be understood that although the terms first, second, third, etc., may be used herein to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this document, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if," as used herein, may be interpreted as "when," "when," or "in response to determination." Furthermore, as used herein, the singular forms "a," "an," and "the" are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising," "including," indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or," "and / or," "including at least one of the following," etc., as used in this application, may be interpreted as inclusive, or mean any one or any combination thereof. For example, "including at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Similarly, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Exceptions to this definition only occur when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0029] It should be understood that although the steps in the flowcharts of this application's embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0030] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0031] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0032] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0033] like Figure 1 As shown, this application embodiment provides a flexible printed circuit board (FPC) 100, including at least two conductive layers 110 and a plurality of insulating layers 120. The at least two conductive layers 110 and the plurality of insulating layers 120 are stacked along the thickness direction of the flexible circuit board 100, and at least one insulating layer 120 is distributed between any two adjacent conductive layers 110.

[0034] In some embodiments, the flexible circuit board 100 includes two conductive layers 110 and a plurality of insulating layers 120. Along the thickness direction of the flexible circuit board 100, the two conductive layers 110 and the plurality of insulating layers 120 are stacked sequentially, and one or more insulating layers 120 are distributed between the two conductive layers 110.

[0035] In some embodiments, the number of conductive layers 110 can be three or more, the insulating layer 120 and the conductive layer are stacked sequentially along the thickness direction of the flexible circuit board 100, and one or more insulating layers 120 are distributed between two adjacent conductive layers 110.

[0036] Optionally, the conductive layer 110 is used for signal transmission. The insulating layer 120 located between the two conductive layers 110 can prevent the two conductive layers 110 from being electrically connected, and can reduce mutual interference between signals transmitted on adjacent conductive layers 110 through the insulating effect of the insulating layer 120. In this embodiment, the conductive layer 110 can transmit signals of the same frequency band simultaneously, or it can transmit signals of different frequency bands.

[0037] Optionally, when at least two conductive layers 110 in this embodiment transmit signals of different frequency bands, if the materials of the adjacent insulating layers 120 of the corresponding conductive layers 110 are the same, then the material properties of the insulating layers 120 are the same, and the shielding effect on signals of different frequency bands is also the same. This can easily lead to mutual interference between signals of different frequency bands during transmission.

[0038] Optionally, to solve this problem, multiple independent flexible circuit boards 100 are often used to transmit signals of different frequency bands. However, increasing the number of flexible circuit boards 100 leads to increased costs. Furthermore, because the flexible circuit boards 100 are independently arranged and have gaps between them, their space usage increases. Alternatively, transmitting signals of different frequency bands independently results in fewer signals for a particular frequency band, thus reducing the utilization rate of the multiple independent flexible circuit boards 100. Optionally, selecting a material for the insulating layer 120 with good insulation and shielding properties can improve the signal transmission stability of the flexible circuit board 100, but this again increases the cost of the flexible circuit board 100.

[0039] Optionally, in this embodiment, the material of the insulating layer 120 adjacent to at least one conductive layer 110 is different from the material of the other insulating layers 120. Thus, because the insulating layer 120 adjacent to the conductive layer 110 is made of a different material than the other insulating layers 120 of the flexible circuit board 100, the different material properties of the different insulating layers 120 result in different shielding effects on signals. This allows for the transmission of signals in different frequency bands and avoids interference between signals in different frequency bands, enabling effective and stable transmission on the flexible circuit board 100. Optionally, different conductive layers 110 can also transmit signals in the same frequency band; the frequency band of the signal is not required in this embodiment.

[0040] This embodiment of the application, by selecting different insulating layer 120 materials, enables the flexible circuit board 100 to transmit signals of different frequency bands, while also reducing mutual interference between signals of different frequency bands, thus allowing for fast and stable transmission of signals of different frequency bands. Simultaneously, it reduces the number of independently installed flexible circuit boards 100, increasing the integration level of the flexible circuit board 100, and thereby reducing the cost of the flexible circuit board 100 while meeting signal transmission requirements.

[0041] In some embodiments, the insulating layer 120 includes at least two first insulating layers 121 and at least two second insulating layers 122, which are spaced apart along the thickness direction of the flexible circuit board 100. This separation of the conductive layer 110 by the first and second insulating layers 121 and 122 effectively isolates signal transmission, reducing crosstalk and interference between signals and improving signal integrity and reliability. This flexible circuit board 100 allows for the integration of multiple signal types on the same board, offering greater design flexibility and functional integration, further enhancing the utilization rate of the flexible circuit board 100.

[0042] Optionally, in this embodiment, the dielectric constant of the first insulating layer 121 is greater than that of the second insulating layer 122. Optionally, the materials of the first insulating layer 121 and the second insulating layer 122 are different. The first insulating layer 121 has a relatively high dielectric constant, which allows it to form a signal transmission channel with high signal transmission speed and low loss. Simultaneously, the relatively high dielectric constant of the first insulating layer 121 can shorten the signal wavelength, thereby increasing the signal transmission speed. The relatively low dielectric constant of the second insulating layer 122 can reduce signal transmission and loss, ensuring signal integrity.

[0043] Thus, the conductive layer 110 adjacent to the first insulating layer 121 can transmit signals with relatively high frequencies, while the conductive layer 110 adjacent to the second insulating layer 122 can transmit signals with relatively low frequencies.

[0044] Optionally, the insulating layer 120 in this embodiment of the application may be multiple, and the multiple insulating layers 120 may include two first insulating layers 121 and two second insulating layers 122, or two first insulating layers 121 and multiple second insulating layers 122, or multiple first insulating layers 121 and two second insulating layers 122.

[0045] Optionally, the first insulating layer 121 and the second insulating layer 122 are spaced apart along the thickness direction of the flexible circuit board 100. It can be understood that, along the thickness direction of the flexible circuit board 100, the first insulating layer 121 may be located on one side of the flexible circuit board 100, and the second insulating layer 122 may be located on the other side of the flexible circuit board 100. Optionally, a portion of the first insulating layer 121 is located between portions of the second insulating layers 122, and a portion of the second insulating layers 122 is located between portions of the first insulating layers 121. Optionally, a conductive layer 110 is disposed between the first insulating layer 121 and the second insulating layer 122.

[0046] Optionally, the insulating layer 120 includes at least one of a modified polyimide layer (MPI), a liquid crystal polymer layer (LCP), and a polyimide layer (PI), wherein the dielectric constant of the materials of the modified polyimide layer and the liquid crystal polymer layer is relatively greater than the dielectric constant of the material of the polyimide layer.

[0047] When the insulating layer 120 is entirely composed of modified polyimide layer and / or liquid crystal polymer layer, the flexible circuit board 100 can transmit signals of different frequency bands, and the interference between signals of different frequency bands is relatively small. The signal transmission stability and integrity of the flexible circuit board 100 are relatively good. However, it is difficult to reduce the material cost of using modified polyimide layer and / or liquid crystal polymer layer for all insulating layers 120.

[0048] When the insulation layer 120 is entirely made of polyimide, due to the small dielectric constant of the polyimide layer, it can only guarantee the transmission of low-frequency signals and is very unfriendly to high-frequency signals. High-frequency signals are prone to distortion and are easy to interfere with low-frequency signals, resulting in a deterioration in the signal transmission performance of the flexible circuit board 100.

[0049] Optionally, in the embodiments of this application, the first insulating layer 121 includes at least one of a modified polyimide layer and a liquid crystal polymer layer. Optionally, the second insulating layer 122 includes a polyimide layer.

[0050] Optionally, the first insulating layer 121 may be entirely a modified polyimide layer, or entirely a liquid crystal polymer layer, or a portion of the first insulating layer 121 may be a modified polyimide layer and another portion of the first insulating layer 121 may be a liquid crystal polymer layer.

[0051] Optionally, only the first insulating layer 121 is a modified polyimide layer and / or a liquid crystal polymer layer, which satisfies the requirement of stable transmission of high-frequency signals and prevents high-frequency signals from interfering with other signals. Optionally, by using different materials for the first insulating layer 121 and the second insulating layer 122, the cost of the flexible circuit board 100 can be reduced.

[0052] Optionally, the conductive layer 110 adjacent to the second insulating layer 122 can transmit low-frequency signals, and the conductive layer 110 adjacent to the first insulating layer 121 can transmit high-frequency signals. In this embodiment, low-frequency signals can also be transmitted through the conductive layer 110 adjacent to the first insulating layer 121, thereby improving the utilization rate of the flexible circuit board 100.

[0053] To improve the connection performance between the conductive layer 110 and the insulating layer 120, a first connecting layer 130 is provided between at least one conductive layer 110 and at least one adjacent insulating layer 120. In this embodiment, by providing the first connecting layer 130 between the conductive layer 110 and the insulating layer 120, the adhesion between the conductive layer 110 and the insulating layer 120 can be improved, preventing the flexible circuit board 100 from delamination or peeling under bending, stretching, or other mechanical stress, thereby improving the mechanical reliability and durability of the flexible circuit board 100. Simultaneously, the first connecting layer 130 can also act as a barrier, protecting the conductive layer 110 from corrosion by moisture, chemical gases, or other corrosive substances in the external environment, extending the service life of the circuit board.

[0054] Optionally, the first bonding layer 130 may be an adhesive layer.

[0055] In some embodiments, the conductive layer 110 includes a first conductive layer 111 and a second conductive layer 112. The first conductive layer 111 is disposed between two adjacent first insulating layers 121, and the second conductive layer 112 is disposed between two adjacent second insulating layers 122. Optionally, pairing the first conductive layer 111 with the corresponding first insulating layer 121 and pairing the second conductive layer 112 with the corresponding second insulating layer 122 can effectively isolate different signal channels, reduce crosstalk and interference between signals, improve signal integrity and reliability, and thus enhance the signal transmission performance of the flexible circuit board 100.

[0056] Optionally, both the first conductive layer 111 and the second conductive layer 112 can be copper layers.

[0057] In some embodiments, the first conductive layer 111 and the first insulating layers 121 on both sides together form a first signal transmission channel 150. In this way, the first signal transmission channel 150 can shield and isolate electromagnetic interference through the combination of the first insulating layer 121 and the first conductive layer 111, thereby reducing noise and interference during signal transmission.

[0058] Optionally, the second conductive layer 112 and the adjacent second insulating layers 122 together form the second signal transmission channel 160. In this way, the second signal transmission channel 160 can shield and isolate electromagnetic interference through the combination of the second insulating layer 122 and the second conductive layer 112, thereby reducing noise and interference during signal transmission.

[0059] In this embodiment of the application, a second connection layer 140 is provided between the first signal transmission channel 150 and the second signal transmission channel 160. Optionally, the provision of the second connection layer 140 makes the connection between the first signal channel and the second signal transmission channel 160 stable, preventing delamination or peeling of the flexible circuit board 100 during bending and transfer, thereby improving the stability and safety of the flexible circuit board 100.

[0060] Optionally, the second connecting layer 140 in this embodiment can be an adhesive layer.

[0061] In some embodiments, there is at least one first signal transmission channel 150 and at least two second signal transmission channels 160; the at least two second signal transmission channels 160 and at least one first signal transmission channel 150 are alternately stacked along the thickness direction of the flexible circuit board 100. Optionally, by alternately stacking the first signal transmission channels 150 and the second signal transmission channels 160, the number of signal transmission paths can be increased within a limited space, thereby improving signal density and the space utilization of the flexible circuit board 100. Simultaneously, such a flexible circuit board 100 allows different types of signals or signals of different frequency bands to be transmitted independently in different transmission channels through the first signal transmission channels 150 and the second signal transmission channels 160, reducing mutual interference between signals.

[0062] In some implementations, the transmission bandwidth of the first signal transmission channel 150 is greater than that of the second signal transmission channel 160. Optionally, different first signal transmission channels 150 and second signal transmission channels 160 can be allocated according to the bandwidth requirements of different signals to increase the signal transmission rate of the flexible circuit board 100 and reduce signal delay. Simultaneously, each signal is transmitted through its corresponding channel, preventing low-bandwidth signals from being transmitted through the high-bandwidth first signal transmission channel 150, thereby reducing the power consumption of the flexible circuit board 100.

[0063] In some embodiments, the first signal transmission channel 150 is a radio frequency (RF) signal channel, and the second signal transmission channel 160 is a baseband signal channel. RF signals typically have high frequencies and are susceptible to interference. By transmitting the RF signal and the baseband signal through the first signal transmission channel 150 and the second signal transmission channel 160 respectively, mutual interference and crosstalk between the RF signal and the baseband signal can be reduced, improving the integrity and stability of each signal.

[0064] Optionally, the number of the first signal transmission channel 150 and the second signal transmission channel 160 can be selected according to the number of corresponding radio frequency signals and the number of corresponding baseband signals. Furthermore, the layer order of the first signal transmission channel 150 and the second signal transmission channel 160 along the thickness direction of the flexible circuit board 100 can also be selected.

[0065] The flexible circuit board 100 provided in this application includes at least two conductive layers 110 and a plurality of insulating layers 120. The at least two conductive layers 110 and the plurality of insulating layers 120 are stacked along the thickness direction of the flexible circuit board 100, and at least one insulating layer 120 is distributed between any two adjacent conductive layers 110. Optionally, the material of the insulating layer 120 adjacent to at least one conductive layer 110 is different from the material of the other insulating layers 120. Such a flexible circuit board 100 can transmit multiple different signals simultaneously, improving the integration density of the flexible circuit board 100. By using different materials for the insulating layers 120, mutual interference between different signals is avoided, improving the stability and integrity of signal transmission by the flexible circuit board 100. Simultaneously, it can also improve the utilization rate of the flexible circuit board 100 and reduce the material cost of the flexible circuit board 100.

[0066] This application provides a smart terminal 200, including a power supply device 230 and a flexible circuit board 100 as described in the first aspect; optionally, the flexible circuit board 100 and the power supply device 230 are electrically connected.

[0067] Optionally, the smart terminal 200 in this application embodiment can be a mobile phone, computer, monitor, etc., wherein the mobile phone can be a foldable mobile phone.

[0068] See Figure 2 The smart terminal 200 includes two housings 210, which can be connected by a pivot 220 to enable the smart terminal 200 to be folded. A power supply device 230 and a printed circuit board 240 are respectively provided in the two housings 210. The printed circuit boards 240 in the two housings 210 are connected by the flexible circuit board 100 provided in the first aspect of this application.

[0069] Optionally, the power supply device 230 in this embodiment is a battery.

[0070] The smart terminal 200 provided in this application embodiment, by including the flexible circuit board 100 provided in the first aspect, can improve the stability and integrity of signal transmission and reduce material costs.

[0071] It is understood that the above scenarios are merely examples and do not constitute a limitation on the application scenarios of the technical solutions provided in the embodiments of this application. The technical solutions of this application can also be applied to other scenarios. For example, as those skilled in the art will know, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0072] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0073] The units in the device of this application embodiment can be merged, divided, and deleted according to actual needs.

[0074] In this application, identical or similar terms, concepts, technical solutions, and / or application scenario descriptions are generally described in detail only upon their first appearance. Subsequent recurrences are generally not repeated for brevity. When understanding the technical solutions and other content of this application, for identical or similar terms, concepts, technical solutions, and / or application scenario descriptions not described in detail later, reference can be made to their preceding detailed descriptions. Furthermore, in this application, the descriptions of each embodiment have their own emphasis; parts not detailed or recorded in a certain embodiment can be referred to the relevant descriptions of other embodiments.

[0075] The technical features of the present application can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present application.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A flexible circuit board, characterized by, The flexible circuit board (100) comprises: at least two conductive layers (110) and insulating layers (120), the at least two conductive layers (110) and the insulating layers (120) are arranged in a stacking manner along the thickness direction of the flexible circuit board (100), and at least one insulating layer (120) is distributed between any two adjacent conductive layers (110); the material of the insulating layer (120) adjacent to at least one conductive layer (110) is different from the material of the remaining insulating layers (120).

2. The flexible circuit board of claim 1, wherein, The insulating layer (120) comprises at least two first insulating layers (121) and at least two second insulating layers (122), the first insulating layers (121) and the second insulating layers (122) are arranged in a spaced manner along the thickness direction of the flexible circuit board (100); The dielectric constant of the first insulating layer (121) is greater than the dielectric constant of the second insulating layer (122).

3. The flexible circuit board of claim 2, wherein, The conductive layer (110) comprises a first conductive layer (111) and a second conductive layer (112), the first conductive layer (111) is arranged between two adjacent first insulating layers (121), and the second conductive layer (112) is arranged between two adjacent second insulating layers (122).

4. The flexible circuit board of claim 2, wherein, The first insulating layer (121) comprises at least one of a modified polyimide layer and a liquid crystal polymer layer; and / or, the second insulating layer (122) comprises a polyimide layer.

5. The flexible circuit board of claim 3, wherein, The first conductive layer (111) and the first insulating layers (121) on both sides thereof jointly form a first signal transmission channel (150), the second conductive layer (112) and the second insulating layers (122) on both sides thereof jointly form a second signal transmission channel (160), and a second connecting layer (140) is arranged between the first signal transmission channel (150) and the second signal transmission channel (160).

6. The flexible circuit board of claim 5, wherein, The first signal transmission channel (150) is at least one, and the second signal transmission channel (160) is at least two; The at least two second signal transmission channels (160) and the at least one first signal transmission channel (150) are arranged in a stacked manner along the thickness direction of the flexible circuit board (100).

7. The flexible circuit board of claim 5, wherein, The transmission bandwidth of the first signal transmission channel (150) is greater than the transmission bandwidth of the second signal transmission channel (160); and / or, the first signal transmission channel (150) is a radio frequency signal channel, and the second signal transmission channel (160) is a baseband signal channel.

8. The flexible circuit board according to any one of claims 1 to 7, characterized by, A first connecting layer (130) is arranged between the at least one conductive layer (110) and the at least one insulating layer (120) adjacent thereto.

9. A smart terminal, characterized by The smart terminal further comprises a power supply device (230); the flexible circuit board (100) and the power supply device (230) are electrically connected.

10. The intelligent terminal of claim 9, wherein, The smart terminal further comprises a power supply device (230); the flexible circuit board (100) and the power supply device (230) are electrically connected.

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