Flexible circuit board for multiple signal transmission

Abstract

A flexible circuit board for multiple signal transmission includes a first dielectric layer, a plurality of first side grounds formed in parallel on one face of the first dielectric layer, a first signal line formed between each of the plurality of first side grounds, and a plurality of through holes formed in each of the plurality of first side grounds at intervals from each other along a length direction of the first side ground.

Description

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to a flexible circuit board for multiple signal transmission. BACKGROUND

[0002] A base station system includes a digital signal processing unit (DU) that takes charge of digital signal processing, and a radio signal processing unit (RU) that converts a digital signal into an RF signal or converts an RF signal into a digital signal and transmits / receives between an antenna and the digital signal processing unit.

[0003] A coaxial cable is used in transmitting / receiving information between such a digital signal processing unit and a radio signal processing unit. However, recently, more than 100 coaxial cables are required in a 5G environment, and a space for configuring the coaxial cables is expanded, so there is a problem in realizing miniaturization.

[0004] Patent Document 1: Korean Patent Publication No. KR10-2018-0037914A SUMMARY

[0005] The present invention is proposed to improve the above-described problems, and realizes miniaturization by applying a single flexible circuit board (FPCB) instead of a plurality of coaxial cables. Specifically, signal transmission / reception can be performed by forming a plurality of signal transmission lines in a flexible circuit board instead of coaxial cables.

[0006] In particular, the present invention aims to provide a flexible circuit board for multiple signal transmission that can improve signal quality and minimize process defects while minimizing size and area.

[0007] However, such problems are exemplary, and the scope of the present invention is not limited thereto.

[0008] According to an embodiment of the present invention, the flexible circuit board for multiple signal transmission can include a first dielectric layer; a plurality of first side grounds formed in parallel on one surface of the first dielectric layer; a plurality of first signal lines formed between each of the plurality of first side grounds, respectively; and a plurality of through holes formed at intervals from each other along a length direction of the first side ground in each of the plurality of first side grounds, and a region of the one surface of the first dielectric layer in which the one surface on which the first side ground is formed is exposed through the plurality of through holes.

[0009] According to an embodiment, the plurality of first signal lines can each be formed of one or more than two signal lines.

[0010] According to an embodiment, the plurality of through holes can each be a slit shape formed long in the length direction.

[0011] According to an embodiment, the plurality of through holes formed in at least one of the plurality of first side grounds can be arranged in a row.

[0012] According to an embodiment, the center of a through hole formed in an arbitrary one of the plurality of first side grounds and the center of a through hole formed in another first side ground adjacent to the arbitrary one of the plurality of first side grounds can not be disposed on the same straight line parallel to the width direction of the first side ground.

[0013] According to an embodiment, the multi-signal transmission flexible circuit board can further include: a plurality of second side grounds formed on a bottom surface of the first dielectric layer; and a second dielectric layer formed on a bottom surface of the plurality of second side grounds.

[0014] According to an embodiment, the second side grounds can be formed along the length direction under the region in which the first side grounds are formed, and a cavity line can be formed between the second side grounds and under the region in which the first signal lines are formed.

[0015] According to an embodiment, a multi-signal transmission flexible circuit board can include: a first dielectric layer; a plurality of first side grounds formed in parallel on one surface of the first dielectric layer; a plurality of first signal lines respectively formed between each of the plurality of first side grounds; a plurality of second side grounds formed on a bottom surface of the first dielectric layer; and a second dielectric layer formed on a bottom surface of the plurality of second side grounds, the second side grounds being formed along the length direction of the first side grounds under the region in which the first side grounds are formed, and a cavity line being formed between the second side grounds and under the region in which the first signal lines are formed, the cavity line including at least two cavity lines spaced apart based on a direction crossing the length direction of the first signal lines.

[0016] According to an embodiment, a multi-signal transmission flexible circuit board can include: a first dielectric layer; a plurality of first side grounds formed in parallel on one surface of the first dielectric layer; a plurality of first signal lines respectively formed between each of the plurality of first side grounds; a plurality of second side grounds formed on a bottom surface of the first dielectric layer; and a second dielectric layer formed on a bottom surface of the plurality of second side grounds, the second side grounds being formed along the length direction of the first side grounds under the region in which the first side grounds are formed, and a cavity line being formed between the second side grounds and under the region in which the first signal lines are formed, the cavity line being formed long in the length direction of the first signal lines.

[0017] According to an embodiment, the cavity line can be a slit formed by the second side ground, the first dielectric layer, and the second dielectric layer.

[0018] According to an embodiment, the second side ground can include a plurality of through-holes formed at intervals along the length direction.

[0019] According to an embodiment, the multi-signal transmission flexible printed circuit board can further include a third dielectric layer facing one surface of the first dielectric layer, and an upper ground formed on one surface of the third dielectric layer.

[0020] According to an embodiment, the upper ground can include a plurality of through-holes.

[0021] According to an embodiment, a portion of the upper ground on an area where the first signal line is formed can not include a through-hole, and a portion of the upper ground on an area where the first signal line is not formed can include a through-hole.

[0022] According to an embodiment, the multi-signal transmission flexible printed circuit board can further include a lower ground formed on a bottom surface of the second dielectric layer.

[0023] According to an embodiment, the multi-signal transmission flexible printed circuit board can further include a fourth dielectric layer formed on a bottom surface of the lower ground, a plurality of third side grounds formed in parallel on a bottom surface of the fourth dielectric layer, and a plurality of second signal lines formed between each of the plurality of third side grounds.

[0024] According to an embodiment, each of the plurality of third side grounds can include a plurality of through-holes formed at intervals along the length direction.

[0025] According to an embodiment, the plurality of second signal lines can each be formed by one or more signal lines.

[0026] According to an embodiment, the lower ground can include a plurality of through-holes, a portion of the lower ground on an area where the plurality of second signal lines are formed can not include a through-hole, and a portion of the lower ground on an area where the plurality of second signal lines are not formed can include a through-hole.

[0027] According to an embodiment, one of the plurality of first signal lines and the plurality of second signal lines can be a high-speed signal transmission signal line, and the remaining one can be a low-speed signal transmission signal line.

[0028] According to an embodiment, both ends of the plurality of first signal lines can be connected to a digital signal processing unit and an RF signal processing unit, respectively.

[0029] According to an embodiment, the plurality of first signal lines disposed in the central region of the flexible circuit board can be high-speed signal transmission signal lines, and the plurality of first signal lines disposed in the peripheral region of the flexible circuit board can be low-speed signal transmission signal lines.

[0030] According to an embodiment, the interval between the high-speed signal transmission signal lines can be wider than the interval between the low-speed signal transmission signal lines.

[0031] According to an embodiment, the width of the first side ground formed between the high-speed signal transmission signal lines among the plurality of first side grounds can be wider than the width of the first side ground formed between the low-speed signal transmission signal lines.

[0032] According to an embodiment, the first side ground formed between the high-speed signal transmission signal lines among the plurality of first side grounds can have a through-hole, and the first side ground formed between the low-speed signal transmission signal lines among the plurality of first side grounds can not have a through-hole.

[0033] Other aspects, features, and advantages of the present application will become apparent from the following detailed description of the application, the accompanying drawings, and the claims.

[0034] According to an embodiment of the present application as described above, it is possible to improve the signal quality of a flexible circuit board for multiple signal transmission, minimize the size and area, and minimize process defects.

[0035] Of course, the scope of the present application is not limited to such effects. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 FIG. 1 is a perspective view of a flexible circuit board 100 for multiple signal transmission according to an embodiment of the present application.

[0037] Figure 2 FIG. 2 is a cross-sectional view of the flexible circuit board 100 for multiple signal transmission according to an embodiment of the present application.

[0038] Figure 3 FIG. 3 is a cross-sectional view of a flexible circuit board 100b for multiple signal transmission according to an embodiment of the present application.

[0039] Figure 4 FIG. 4 is a cross-sectional view of a flexible circuit board 100c for multiple signal transmission according to an embodiment of the present application.

[0040] Figure 5is a cross-sectional view of a flexible circuit board 100d for multiple signal transmission according to an embodiment of the present application.

[0041] Figure 6 is a cross-sectional view of a flexible circuit board 100e for multiple signal transmission according to an embodiment of the present application.

[0042] Figure 7 is a perspective view of a device 200 for multiple signal transmission according to an embodiment of the present application.

[0043] Figure 8 is Figure 7 is an enlarged view of an area between Al and A2 of the device 200 for multiple signal transmission shown in FIG. 8.

[0044] Figure 9 is a plan view of an upper ground 180 according to an embodiment of the present application.

[0045] Figure 10 is a plan view of a state in which a B2 area of the upper ground 180 covers only a part of a Bl area including a first signal line S1 and a first side ground 150 according to an embodiment of the present application.

[0046] (Explanation of Reference Numerals)

[0047] 100, 100a, 100b, 100c, 100d, 100e, 100f: Flexible circuit board for multiple signal transmission

[0048] 110: First dielectric layer 120: Second dielectric layer

[0049] 130: Third dielectric layer 140: Fourth dielectric layer

[0050] 150: First side ground 160: Second side ground

[0051] 170: Third side ground 180: Upper ground

[0052] 190: Lower ground S1: First signal line

[0053] S2: Second signal line H: Through-hole

[0054] CL: Cavity line 200: Device for multiple signal transmission

[0055] 200F: Flexible portion 200R: Rigid portion

[0056] 201: First connector 202: Second connector

[0057] PW: Power transmission line CA: Central area

[0058] OA: Peripheral Area Detailed Implementation

[0059] This invention can be modified in various ways and can have various embodiments, specific embodiments of which are illustrated in the accompanying drawings and described in detail in the accompanying description. The effects, features, and methods of implementing the invention are described with reference to the accompanying drawings. Figure 1 The details will become clear from the embodiments described below. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms.

[0060] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the drawings, the same or corresponding components will be labeled with the same reference numerals, and repeated descriptions of them will be omitted.

[0061] In the following embodiments, the terms "first," "second," etc., are not limiting; their purpose is to distinguish one constituent element from other constituent elements.

[0062] In the following embodiments, the singular expression includes the plural expression unless there is an explicit difference in context.

[0063] In the following embodiments, terms such as "comprising" or "having" refer to the presence of features or constituent elements described in the specification, and do not preclude the possibility of adding more than one other feature or constituent element.

[0064] In the accompanying drawings, the dimensions of the constituent elements may be enlarged or reduced for ease of illustration. For example, the dimensions and thicknesses of the various structures shown in the drawings are arbitrarily depicted for ease of explanation, and therefore the invention is not necessarily limited to the figures.

[0065] In the following embodiments, when a part referred to as a region, layer, or constituent element is located on or above other parts, it includes not only the case where it is directly located on other parts, but also the case where other regions, layers, constituent elements, etc. are interspersed therein.

[0066] In the following embodiments, when referred to as "connected components, etc.", it includes not only the case where the components are directly connected, but also the case where they are indirectly connected by other components in between.

[0067] Figure 1 This is a perspective view of a flexible circuit board 100 for multiple signal transmission according to an embodiment of the present invention.

[0068] Reference Figure 1The flexible circuit board 100 for multiple signal transmission according to an embodiment of the present application includes a first dielectric layer 110, a plurality of first side grounds 150 formed in parallel on one side of the first dielectric layer 110, and a first signal line S1 formed between each of the plurality of first side grounds 150. In each of the plurality of first side grounds 150, a plurality of through-holes H are formed at intervals from each other along a length direction of the first side ground 150.

[0069] The first signal line S1 and the first side ground 150 can be formed in parallel with each other. Accordingly, the length direction of the first signal line S1 can be the same as the length direction of the first side ground 150. In the following drawings, an x direction indicates the length direction, a y direction indicates a direction perpendicular to the length direction of the first signal line S1 (or a width direction), and a z direction indicates a direction perpendicular to the flexible circuit board 100. However, such direction indications are for the convenience of explanation of positional relationships, and thus should not be construed as limiting, but should be construed as flexible depending on a viewing direction.

[0070] Generally, if a plurality of signal lines are formed in a flexible circuit board having a limited area, spaces between the plurality of signal lines become narrow. Also, a ground line for shielding between adjacent signal lines needs to be formed between the signal lines, and thus the spaces between the signal lines become narrower. In this case, in a process of coupling a connector to the flexible circuit board through an SMT (surface mount technology) process, a problem of thermal expansion of the signal lines and the ground line to be in contact with each other can occur.

[0071] According to an embodiment, the plurality of through-holes H are formed in each of the first side grounds 150, thereby having an effect of limiting thermal expansion of the first side ground 150. Specifically, a change in an outer shape of the first side ground 150 can be minimized even under thermal expansion of the first side ground 150, and thus contact can be prevented.

[0072] According to an embodiment, each of the plurality of through-holes H can be a slit shape formed long along the length direction. Since the first side ground 150 is in a linear form, when the through-hole H is formed in a slit shape formed long along the length direction of the first side ground 150, expansion in front and back and left and right of the first side ground 150 can be most effectively minimized.

[0073] According to an embodiment, the plurality of through-holes H formed in any one of the first side ground 150 can be arranged in a row. In other words, the plurality of through-holes H formed in any one of the first side ground 150 can be configured to pass through an axis along a length direction of the first side ground 150. When the plurality of through-holes H formed in each of the first side grounds 150 are arranged in a row, the width (narrowness) of the first side ground 150 can be minimized. That is, miniaturization of the flexible circuit board 100 can be achieved.

[0074] According to an embodiment, the through-hole H formed in any one of the first side ground 150 and the through-hole H formed in another first side ground 150 adjacent to the first side ground 150 can be formed in a zigzag shape. In other words, the through-hole H formed in any one of the first side ground 150 and the through-hole H formed in another first side ground 150 adjacent to the first side ground 150 can not pass through a straight line along a width direction of the first side ground 150 at the same time. In other words, a first through-hole H formed in any one of the first side grounds 150 and a second through-hole H formed in another first side ground 150 adjacent to the first side ground 150 can be configured not to pass through a straight line parallel to the width direction of the first side ground 150 at the same time. In other words, a plurality of first through-holes H formed in a first side ground 150 on one side of any one of the first signal lines S1 and a plurality of second through-holes H formed in a first side ground 150 on the other side of the any one of the first signal lines S1 can be formed in a zigzag shape with each other. However, this is only an embodiment, and the present application is not limited thereto. According to another embodiment, the first through-hole H formed in any one of the first side grounds 150 and the second through-hole H formed in another first side ground 150 adjacent to the first side ground 150 can also be configured to pass through a straight line parallel to the width direction of the first side ground 150 at the same time. For example, the first through-hole H and the second through-hole H can be configured to pass through the straight line in the width direction at the same time, and the "center" of the first through-hole H and the "center" of the second through-hole H can not pass through the straight line at the same time. In other words, a part of the first through-hole H and a part of the second through-hole H can be configured to pass through the straight line in the width direction at the same time, and the "center" of the first through-hole H and the "center" of the second through-hole H can be configured in a zigzag shape.

[0075] As described above, the through-holes H formed in any one of the first side grounds 150 and another first side ground 150 adjacent thereto are formed in a zigzag shape with each other, so that the electrical wave interference between the adjacent first signal lines S1 can be minimized.

[0076] Figure 2 FIG. 1 is a plan view of a flexible circuit board 100 according to an embodiment of the present application. Figure 2An embodiment in which the through-holes H formed in the first side grounds 150 adjacent to each other are not formed in a zigzag shape is shown. In other words, in the embodiment shown in FIG. 1, the through-holes H formed in the first side ground 150 and the through-holes H formed in the first side ground 150 adjacent to the first side ground 150 are formed to pass through straight lines parallel to the width direction (y-axis direction). Figure 2 In the embodiment shown, the through-holes H formed in an arbitrary first side ground 150 and the through-holes H formed in another first side ground 150 adjacent to the first side ground 150 can pass through straight lines parallel to the width direction (y-axis direction) at the same time.

[0077] According to an embodiment, each first signal line S1 can be formed of one or more than two signal lines. Referring to FIG. 2, each first signal line S1 is formed of two signal lines. Figure 1 In addition, each first signal line S1 can be formed of one signal line. Figure 2 When each first signal line S1 is formed of more than two signal lines, even if signal transmission through one signal line is problematic, signal transmission through another signal line is possible. For example, one signal line and another signal line can transmit the same signal.

[0078] Figure 3 is a cross-sectional view of a flexible circuit board 100b for multiple signal transmission according to an embodiment of the present application.

[0079] Referring to FIG. 3, the flexible circuit board 100b for multiple signal transmission according to an embodiment can further include a plurality of second side grounds 160 formed on a bottom surface of the first dielectric layer 110 and a second dielectric layer 120 formed on a bottom surface of the plurality of second side grounds 160, compared to the flexible circuit board 100a described above. Figure 3 The second side grounds 160 formed on the bottom surface of the first dielectric layer 110 contribute to shielding of the first signal lines S1 and can reduce signal interference between the first signal lines S1. In addition, the second dielectric layer 120 formed on the bottom surface of the second side grounds 160 can planarize the entire flexible circuit board 100b.

[0080] On the other hand, generally, if a plurality of signal lines are formed in a flexible circuit board, there is a problem in that the periphery of the signal lines of the flexible circuit board protrudes due to the height of the signal lines. For example, a portion of the dielectric layer covering or supporting the signal lines can protrude like a drum. If the surface of the periphery of the signal lines protrudes, malfunctions and product damage can occur. In addition, a gap is generated in the dielectric space of the periphery of the signal lines, and there is a problem in that the electrical characteristics of the signal lines are degraded.

[0081]

[0082] ​According to an embodiment of the present application, the second side ground 160 can be formed along the length direction under the area where the first side ground 150 is formed. A cavity line CL can be formed between the second side ground 160 and under the area where the first signal line S1 is formed. The cavity line CL can be formed along the area where the first signal line S1 is formed, under the area where the first signal line S1 is formed.

[0083] Under the area where the first signal line S1 is formed, a gap, i.e., a cavity line CL, is formed, thereby enabling the overall appearance of the flexible circuit board 100b to be flattened. Specifically, even if the bottom surface of the first dielectric layer 110 is convex due to the height of the first signal line S1, the cavity line CL can accommodate the convex portion. Thus, the second dielectric layer 120 can be formed flat, having the effect that the surface of the signal line periphery in the flexible circuit board 100b is not convex. On the other hand, the second side ground 160 formed under the area where the first side ground 150 is formed can support the periphery of the cavity line CL, and can enable the flexible circuit board 100b to have an overall flat appearance.

[0084] According to an embodiment, a plurality of through-holes H can be formed in each of the second side grounds 160, formed at intervals from each other along the length direction. The plurality of through-holes H formed in each of the second side grounds 160 can minimize appearance changes caused by thermal expansion of the second side ground 160.

[0085] Figure 4 FIG. 7 is a cross-sectional view of a flexible circuit board 100c for multiple signal transmission according to an embodiment of the present application.

[0086] Referring to Figure 4 Compared with the flexible circuit board 100b described above, the flexible circuit board 100c for multiple signal transmission according to an embodiment can further include a third dielectric layer 130 facing one surface of the first dielectric layer 110 and an upper ground 180 formed on one surface of the third dielectric layer 130. The upper ground 180 shields the first signal line S1 and can reduce the electric wave interference of the first signal line S1.

[0087] The upper ground 180 is formed in a plate shape as a whole, and thus can be subject to large thermal expansion when heat is applied in a process. For example, there can be a problem in which the upper ground 180 is expanded to become uneven or bent.

[0088] To solve such a problem, according to an embodiment, a plurality of through-holes H can be formed in the upper ground 180. By forming the plurality of through-holes H in the upper ground 180, even the plate-shaped upper ground 180 can minimize deformation caused by thermal expansion.

[0089] An example in which a plurality of through-holes H are formed in the upper ground 180 can be as shown in FIG. 1B. Figure 9 Figure 9 is a plan view of the upper ground 180 according to an embodiment of the present application.

[0090] Figure 5 is a cross-sectional view of a flexible circuit board 100d for multiple signal transmission according to an embodiment of the present application.

[0091] Referring to Figure 5 , the flexible circuit board 100d for multiple signal transmission according to an embodiment can further include a lower ground 190 formed on a bottom surface of the second dielectric layer 120 in the flexible circuit board 100c as shown in FIG. 1C. Figure 4

[0092] The lower ground 190 can shield the first signal line S1, and another signal line can be formed below the lower ground 190. That is, a plurality of signal lines can be formed.

[0093] Figure 6 is a cross-sectional view of a flexible circuit board 100e for multiple signal transmission according to an embodiment of the present application.

[0094] Referring to Figure 6 , the flexible circuit board 100e for multiple signal transmission according to an embodiment can further include a fourth dielectric layer 140 formed on a bottom surface of the lower ground 190, a plurality of third side grounds 170 formed in parallel on a bottom surface of the fourth dielectric layer 140, and a second signal line S2 formed between each of the plurality of third side grounds 170, as compared with the flexible circuit board 100d described above.

[0095] The second signal line S2 can transmit a signal different from the first signal line S1 without interference from the first signal line S1 through the lower ground 190. By forming the first signal line S1 and the second signal line S2 in different layers from each other, it is possible to minimize the area of the flexible circuit board 100e for multiple signal transmission.

[0096] On the other hand, it is shown in Figure 6 that the second signal line S2 is disposed below the first signal line S1, but the present application is not limited thereto. The second signal line S2 can be independently disposed with respect to the first signal line S1 regardless of the disposition of the first signal line S1. That is, the second signal line S2 and the first signal line S1 can not be disposed on the same z-axis.

[0097] According to an embodiment, a plurality of through-holes H can be formed in each of the plurality of third side grounds 170 at intervals from each other along the length direction of the third side ground 170.

[0098] ​​By forming a plurality of through-holes H in each of the third side grounds 170 formed between each of the second signal lines S2, an effect of restricting thermal expansion of the third side ground 170 is obtained. Specifically, since the outer shape of the third side ground 170 can be minimized under thermal expansion of the third side ground 170, conduction can be prevented.

[0099] According to an embodiment, each of the second signal lines S2 can be formed of one or more than two signal lines. When each of the second signal lines S2 is formed of more than two signal lines, even if a problem occurs in signal transmission based on one signal line, signal transmission can be performed through another signal line.

[0100] According to an embodiment, one of the first signal line S1 and the second signal line S2 can be a high-speed signal transmission signal line, and the remaining one can be a low-speed signal transmission signal line.

[0101] The first signal line S1 and the second signal line S2 can perform different roles from each other. For example, among the first signal line S1 and the second signal line S2, a high-speed signal transmission signal line (for example, a 10 GHz differential line) can transmit a high-speed signal of 1 Gbps or more, and a low-speed signal transmission signal line (for example, a control differential line, a control single line) can transmit a low-speed signal of less than 1 Gbps.

[0102] According to an embodiment, when it is assumed that a connector connected to a digital signal processing unit or an RF signal processing unit is disposed above the flexible circuit board 100e, the first signal line S1 close to the connector can be a high-speed signal transmission signal line, and the second signal line S2 away from the connector can be a low-speed signal transmission signal line.

[0103] Of course, in another embodiment, if the connector is disposed below the flexible circuit board 100e, the second signal line S2 close to the connector can be a high-speed signal transmission signal line, and the first signal line S1 away from the connector can be a low-speed signal transmission signal line.

[0104] Thus, by making the high-speed signal transmission path the shortest distance, the signal transmission performance of the flexible circuit board 100e for multiple signal transmission can be improved.

[0105] Figure 7 is a perspective view of a device 200 for multiple signal transmission according to an embodiment of the present application.

[0106] Referring to Figure 7According to an embodiment, the multi-signal transmission device 200 can include a flexible portion 200F and rigid portions 200R at both ends of the flexible portion 200F. The flexible portion 200F can include the flexible circuit board 100, 100a, 100b, 100c, 100d, 100e according to various embodiments described above.

[0107] According to an embodiment, the rigid portions 200R can be formed by adhering another layer having high rigidity to both ends of the flexible portion 200F.

[0108] The rigid portions 200R at both ends of the flexible portion 200F can form a first connector 201 and a second connector 202, respectively. The flexible portion 200F can include a flexible circuit board (for example, the flexible circuit board 100, 100a, 100b, 100c, 100d, 100e) having a signal line (for example, the first signal line S1 and / or the second signal line S2) connecting the first connector 201 and the second connector 202.

[0109] One of the first connector 201 and the second connector 202 can be connected to the digital signal processing portion, and the remaining one can be connected to the RF signal processing portion. Accordingly, the first signal line S1 can perform transceiving between the digital signal processing portion and the RF signal processing portion. At this time, by using the first signal line S1 formed in the flexible circuit board instead of using a coaxial cable, it is possible to miniaturize the signal transmission device.

[0110] Figure 8 is Figure 7 is an enlarged view of the inside of the area between A1 and A2 of the multi-signal transmission device 200. That is, the flexible portion 200F of the multi-signal transmission device 200 can include a flexible circuit board 100f. The flexible circuit board 100f includes a first dielectric layer 110, a first signal line S1, and a first side ground 150. According to an embodiment, Figure 8 is a flexible circuit board 100f according to an embodiment. Figure 1 is a flexible circuit board 100 and its peripheral portion according to an embodiment. Figure 8 is a flexible circuit board 100f according to an embodiment. Figure 1 is an enlarged view of the flexible circuit board 100 according to an embodiment.

[0111] However, the flexible portion 200F of the multiplex signal transmission device 200 according to various embodiments of the present application is not limited to the flexible circuit board 100f. The flexible portion 200F of the multiplex signal transmission device 200 according to various embodiments can include one or more of the aforementioned second side ground 160, the second dielectric layer 120, the third dielectric layer 130, the upper ground 180, the lower ground 190, the fourth dielectric layer 140, the second signal line S2, and the third side ground 170 in addition to the first dielectric layer 110, the first signal line S1, and the first side ground 150.

[0112] According to an embodiment, the first signal line S1 disposed in the central area CA of the flexible circuit board 100f can be a high-speed signal transmission signal line, and the first signal line S1 disposed in the outer area OA of the flexible circuit board 100f can be a low-speed signal transmission signal line.

[0113] By disposing the high-speed signal transmission signal line in the central area CA of the flexible circuit board 100f, the high-speed signal transmission path can be made to have the shortest distance. Thus, the performance of the multiplex signal transmission device 200 can be improved.

[0114] According to an embodiment, the interval between the high-speed signal transmission signal lines can be wider than the interval between the low-speed signal transmission signal lines.

[0115] According to an embodiment, the width of the first side ground 150 formed between the high-speed signal transmission signal lines among the plurality of first side grounds 150 can be wider than the width of the first side ground 150 formed between the low-speed signal transmission signal lines.

[0116] According to the above-described embodiment, by forming the interval between the high-speed signal lines to be wider than the interval between the low-speed signal lines, the width of the first side ground 150 between the high-speed signal lines can be formed to be wider, and thus the reliability of high-speed signal transmission can be maintained.

[0117] According to an embodiment, among the plurality of first side grounds 150, the first side ground 150 formed between the high-speed signal transmission signal lines can have a through-hole H, and the first side ground 150 formed between the low-speed signal transmission signal lines among the plurality of first side grounds 150 can not have a through-hole H.

[0118] The width of the first side ground 150 between the low-speed signal lines is formed to be narrower than the width of the first side ground 150 between the high-speed signal lines, and thus the first side ground 150 formed between the low-speed signal lines does not have a through-hole H, and thus the overall width of the flexible circuit board 100f can be minimized.

[0119] On the other hand, a power transmission line PW can be formed on one side of the first signal line S1.

[0120] On the other hand, as described above, in various embodiments, the multiple signal transmission device 200 can further include a third dielectric layer 130 facing one side of the first dielectric layer 110 and an upper ground 180 formed on one side of the third dielectric layer 130. That is, the multiple signal transmission device 200 according to various embodiments can include the flexible circuit board 100c, 100d, 100e described above.

[0121] Figure 9 is a plan view of the upper ground 180 according to an embodiment of the present application. Figure 9 The upper ground 180 shown can be disposed on Figure 8 the upper side of the flexible circuit board 100f shown. Referring to Figure 9 A plurality of through holes H can be formed in the upper ground 180.

[0122] Hereinafter, referring to Figure 8 the B1 region shown and Figure 9 the B2 region shown, the positional relationship of the first signal line S1 and the upper ground 180 will be described.

[0123] Figure 10 is a plan view of a state in which the B2 region of the upper ground 180 according to an embodiment of the present application covers only a part of the B1 region including the first signal line S1 and the first side ground 150. The B1 region and the B2 region are shown in Figure 8 and Figure 9 .

[0124] Referring to Figure 10 In an embodiment, a part of the upper ground 180 on a region in which the first signal line S1 is formed can not form a through hole H. In addition, a part of the upper ground 180 on a region in which the first signal line S1 is not present can form a through hole H.

[0125] A part of the upper ground 180 on a region in which the first signal line S1 is formed does not form a through hole H, thereby being able to contribute to shielding of the first signal line S1. In addition, a part of the upper ground 180 on a region in which the first signal line S1 is not present forms a through hole H, thereby being able to minimize thermal expansion of the upper ground 180.

[0126] On the other hand, the positional relationship of the second signal line S2 and the lower ground 190 can also correspond to the positional relationship of the first signal line S1 and the upper ground 180.

[0127] The lower ground 190 can be formed with a plurality of through-holes H, and the portion of the lower ground 190 on the region where the second signal line S2 is formed can not be formed with the through-holes H. In addition, the portion of the lower ground 190 on the region where the second signal line S2 is not present can be formed with the through-holes H.

[0128] The portion of the lower ground 190 on the region where the second signal line S2 is formed is not formed with the through-holes H, thereby being able to contribute to the shielding of the second signal line S2. In addition, the portion of the lower ground 190 on the region where the second signal line S2 is not present is formed with the through-holes H, thereby being able to minimize the thermal expansion of the lower ground 190.

[0129] The present application is described with reference to an embodiment shown in the accompanying drawings, which is merely exemplary, and those skilled in the art will understand that various modifications and variations can be made thereto and that such modifications and variations are within the scope of the present application. Therefore, the true technical protection scope of the present application should be determined by the technical concept of the appended claims.

Claims

1. A flexible circuit board for multiple signal transmission, comprising: First dielectric layer; Multiple first side grounds are formed parallel to one side of the first dielectric layer; A plurality of first signal lines are formed between each of the plurality of first side grounded lines; Multiple through holes are formed at intervals from each of the multiple first side groundings, along the length direction of the first side groundings; Multiple second-side grounds are formed on the bottom surface of the first dielectric layer to overlap with the multiple first-side grounds; A second dielectric layer is formed on the bottom surface of the plurality of second sides grounded; as well as The cavity line overlaps with the plurality of first signal lines between the plurality of second-side grounding points. A region of the surface of the first dielectric layer that forms the grounded side is exposed through the plurality of through holes. The cavity line is a gap formed by the plurality of adjacent second side grounds, the first dielectric layer, and the second dielectric layer.

2. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The plurality of first signal lines are each formed by one or more signal lines.

3. The flexible circuit board for multiple signal transmission according to claim 1, wherein, Each of the plurality of through holes is a slit shape that is formed elongated along the length direction.

4. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The plurality of through holes formed in at least one of the plurality of first side groundings are arranged in a row.

5. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The center of the through hole formed by any of the plurality of first side grounds and the center of the through hole formed by another first side ground adjacent to the first side ground are not arranged on the same straight line parallel to the width direction of the first side ground.

6. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The second side ground is formed along the length direction below the area where the first side ground is formed.

7. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The cavity lines include at least two cavity lines spaced apart based on a direction that intersects the length direction of the first signal line.

8. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The second side ground is formed below the area where the first side ground is formed, along the length direction of the first side ground. The cavity line extends long along the length of the first signal line.

9. The flexible circuit board for multiple signal transmission according to claim 6, wherein, Multiple through holes are formed at intervals along the length direction on each of the second side surfaces.

10. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The flexible circuit board for multiple signal transmission also includes: A third dielectric layer, facing one side of the first dielectric layer; and The upper ground is formed on one side of the third dielectric layer.

11. The flexible circuit board for multiple signal transmission according to claim 10, wherein, Multiple through holes are formed on the ground.

12. The flexible circuit board for multiple signal transmission according to claim 11, wherein, No through-hole is formed in the upper grounding portion of the region where the first signal line is formed. A through-hole is formed in the upper ground portion in the region where the first signal line does not exist.

13. The flexible circuit board for multiple signal transmission according to claim 6, wherein, The flexible circuit board for multiple signal transmission also includes: The bottom ground is formed on the bottom surface of the second dielectric layer.

14. The flexible circuit board for multiple signal transmission according to claim 13, wherein, The flexible circuit board for multiple signal transmission also includes: A fourth dielectric layer is formed on the bottom surface of the lower ground; Multiple third-side grounds are formed parallel to the bottom surface of the fourth dielectric layer; and Multiple second signal lines are formed between each of the multiple third side grounded.

15. The flexible circuit board for multiple signal transmission according to claim 14, wherein, Each of the plurality of third-side grounded areas includes a plurality of through holes formed at intervals along the length direction.

16. The flexible circuit board for multiple signal transmission according to claim 14, wherein, The plurality of second signal lines are each formed by one or more signal lines.

17. The flexible circuit board for multiple signal transmission according to claim 14, wherein, Multiple through holes are formed in the lower grounding section. No through-hole is formed in the lower grounding portion of the region where the plurality of second signal lines are formed. A through-hole is formed in the lower ground portion in the region where the plurality of second signal lines are not present.

18. The flexible circuit board for multiple signal transmission according to claim 14, wherein, One of the plurality of first signal lines and the plurality of second signal lines is a high-speed signal transmission signal line, and the remaining one is a low-speed signal transmission signal line.

19. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The two ends of the plurality of first signal lines are respectively connected to the digital signal processing unit and the RF signal processing unit.

20. The flexible circuit board for multiple signal transmission according to claim 1, wherein, The plurality of first signal lines disposed in the central region of the flexible circuit board are signal lines for high-speed signal transmission. The plurality of first signal lines configured in the peripheral area of ​​the flexible circuit board are signal lines for low-speed signal transmission.

21. The flexible circuit board for multiple signal transmission according to claim 20, wherein, The spacing between the signal lines used for high-speed signal transmission is wider than the spacing between the signal lines used for low-speed signal transmission.

22. The flexible circuit board for multiple signal transmission according to claim 20, wherein, The width of the first side ground formed between the high-speed signal transmission signal lines is wider than the width of the first side ground formed between the low-speed signal transmission signal lines.

23. The flexible circuit board for multiple signal transmission according to claim 20, wherein, A through-hole is formed in one of the plurality of first side grounds between the signal lines for high-speed signal transmission. In the plurality of first side grounds, the first side grounds formed between the signal lines for low-speed signal transmission do not form through holes.

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