Flexible circuit board module and electronic device comprising same

Abstract

A flexible circuit board according to an embodiment of the present invention comprises: a base material including a first surface and a second surface opposite to the first surface; a plurality of wiring patterns disposed on the first surface; and a protective layer disposed on the wiring patterns, wherein the wiring patterns each include: a first pad part connected to a display panel; a second pad part connected to a circuit board; and a region which includes a wiring part connecting the first pad part and the second pad part and in which the width of the wiring part is greater than an interval between wiring parts.

Description

Flexible circuit board module and electronic device including the same

[0001] The present invention relates to a flexible circuit board module and an electronic device including the same.

[0002] Recently, various electronic products are becoming thinner. Furthermore, these products are becoming smaller and lighter. Consequently, there is a growing demand for high-density semiconductor chips in narrow spaces within electronic products.

[0003] Chip on Glass (COG) is a method of mounting a driver chip directly on a display panel that includes a glass substrate.

[0004] The above chip-on-glass is connected to a printed circuit board, such as a main board. The chip-on-glass and the printed circuit board are connected by a connector.

[0005] The connector may include a flexible circuit board. For example, the connector may include an FPCB.

[0006] The above FPCB includes a substrate and a circuit pattern on the substrate. In addition, a cover lay is arranged on the circuit pattern. The cover lay protects the circuit pattern. The cover lay is bonded by an adhesive layer.

[0007] Accordingly, the thickness of the FPCB is increased by the adhesive layer and the cover layer. In addition, the elongation change of the FPCB during the thermocompression process may increase by the cover layer.

[0008] Additionally, the FPCB is formed with the same line width and spacing of the circuit pattern. Accordingly, the area of ​​the circuit pattern placed on the substrate is limited. Consequently, the size of the FPCB can be increased.

[0009] Therefore, a new structure of a flexible circuit board module and an electronic device including the same that can solve the above problems are required.

[0010] As a patent related to the above flexible circuit board module, Korean registered patent KR10-0618898 (2006.09.01) is disclosed.

[0011] The embodiment provides a flexible circuit board module with improved electrical connection characteristics.

[0012] The embodiment provides a flexible circuit board module having a slim size.

[0013] A flexible circuit board according to an embodiment comprises a substrate including a first surface and a second surface opposite to the first surface; a plurality of wiring patterns disposed on the first surface; and a protective layer disposed on the wiring patterns, wherein the wiring patterns include a first pad portion connected to a display panel; a second pad portion connected to a circuit board; and a wiring portion connecting the first pad portion and the second pad portion, and wherein the width of the wiring portion includes a region greater than the spacing between the wiring portions.

[0014] A flexible circuit board module according to an embodiment includes a plurality of flexible circuit boards.

[0015] The above flexible circuit board includes a plurality of wiring patterns. The wiring patterns include a wiring portion, a first pad portion, and a second pad portion.

[0016] The above wiring portion includes a plurality of regions. Any one of the plurality of regions may have a width greater than the spacing between the wiring portions.

[0017] The resistance of the above wiring pattern is inversely proportional to the area of ​​the wiring pattern. Therefore, as the width of the wiring portion increases, the resistance of the wiring pattern decreases. In the flexible circuit board, the area of ​​the wiring pattern increases. Therefore, the resistance of the flexible circuit board decreases.

[0018] In conventional FPCBs, the width of the wiring portions is formed smaller than the spacing between the portions. Consequently, the area of ​​the wiring pattern arranged in the effective area is limited. However, in the embodiment, the width of the wiring portions is formed larger than the spacing between the portions. In other words, compared to the wiring pattern of conventional FPCBs, the pitch is the same, but the width can be increased.

[0019] Accordingly, the resistance of the flexible circuit board decreases. Therefore, the flexible circuit board easily supplies power to the display panel and the printed circuit board. In addition, signals for moving the display panel and the printed circuit board are easily moved by the flexible circuit board.

[0020] Additionally, the flexible circuit board does not include a separate adhesive layer or coverlay. Therefore, the thickness of the flexible circuit board is reduced. Furthermore, the coverlay prevents variations in the ductility during folding.

[0021] Furthermore, when bonding conventional FPCBs and display panels, ACF (anisotropic conductive film) was used. This meant that a separate bonding layer was required. However, the flexible circuit board forms a pad where only pure tin remains, bonding the terminals of the display panel and the terminals of the printed circuit board. Specifically, the tin is melted and bonded using heat and pressure. Consequently, the thickness of the display is reduced.

[0022] Figure 1 is a plan view of an electronic device according to an embodiment.

[0023] Fig. 2 is a drawing showing the connection relationship of an electronic device according to an embodiment.

[0024] Figures 3 and 4 are top views of a flexible circuit board according to an embodiment.

[0025] Figure 5 is an enlarged view of area A of Figure 3.

[0026] Figure 6 is an enlarged view of area B of Figure 3.

[0027] Figure 7 is an enlarged view of area C of Figure 3.

[0028] Figure 8 is a drawing for explaining a cutting pattern of another embodiment.

[0029] Figures 9 to 12 are cross-sectional views taken along the AA' area of ​​Figure 4.

[0030] Figures 13 and 14 are cross-sectional views taken along the BB area and the CC' area of ​​Figure 4, respectively.

[0031] Figures 15 and 16 are cross-sectional views taken along the BB area and the CC' area of ​​Figure 4, respectively.

[0032] Figures 17 and 18 are cross-sectional views taken along the BB area and the CC' area of ​​Figure 4, respectively.

[0033] Figures 19 and 20 are cross-sectional views taken along the B-B' area and the CC' area of ​​Figure 4, respectively.

[0034] Figures 21 to 24 are drawings of electronic devices according to embodiments.

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the described embodiments, but may be implemented in various different forms. Within the scope of the technical concept of the present invention, one or more of the components of the embodiments may be selectively combined or substituted for use.

[0036] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0037] In addition, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “and (and) at least one (or more) of B, C,” it may include one or more of all combinations that can be combined with A, B, and C.

[0038] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0039] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0040] Additionally, when it is described as being formed or disposed "above or below" each component, above or below includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or disposed between the two components.

[0041] Additionally, when expressed as “upper or lower,” it can include the meaning of not only the upward direction but also the downward direction based on one component.

[0042] Additionally, in the following description, the first direction (1D) is defined as the length (vertical) direction of the flexible circuit board. Additionally, the second direction (2D) is defined as the width (horizontal) direction of the flexible circuit board.

[0043]

[0044] Hereinafter, a flexible circuit board module and an electronic device including the same according to an embodiment will be described with reference to the drawings.

[0045] Referring to FIGS. 1 and 2, the electronic device (10) includes a flexible circuit board module (1000), a display panel (2000), and a circuit board (3000).

[0046] The above display panel (2000) and the circuit board (3000) are connected. In detail, the display panel (2000) and the circuit board (3000) are electrically connected by the flexible circuit board module (1000).

[0047] The above display panel (2000) may include a display panel requiring high power. For example, the display panel may be applied to an electronic device such as a laptop.

[0048] The above display panel (2000) includes a first panel (2100), a second panel (2200), a plurality of light-emitting diodes (2300) and a chip (CH).

[0049] At least one of the first panel (2100) and the second panel (220) may include glass.

[0050] The second panel (2200) may be placed on the first panel (2100). The flexible circuit board module (1000) may be connected to at least one of the first panel (2100) and the second panel (2200).

[0051] The light emitting diode (2300) may include a micro LED. The light emitting diode (2300) may be disposed on the first panel (2100) or the second panel (2200). For example, the light emitting diode (2300) may be disposed on the upper portion of the second panel (2200). The flexible circuit board module (100) may be connected to the second panel (2200).

[0052] Alternatively, the light emitting diode (2300) may be placed at the bottom of the first panel (2100). The flexible circuit board module (1000) may be connected to the second panel (2200). Accordingly, the area where the light emitting diode (2300) can be placed may increase.

[0053] The chip (CH) may be placed on the first panel (2100) or the second panel (2200). For example, the chip (CH) may be placed on the second panel (2200). The chip (CH) may be a driver IC.

[0054] For example, the display panel (2000) may be a glass panel on which a chip is mounted. That is, the display panel (200) may be of the chip-on-glass (COG) type.

[0055] The driver IC chip is directly mounted on the display panel. That is, the driver IC chip is formed in a chip-on-glass type on the display panel. Therefore, a separate chip-on-film (COF) is not required, thereby reducing the manufacturing cost of the display. In addition, since the chip on the COF (Chip-on-Film) is directly mounted on the display panel, the thickness of the display is reduced. In addition, when connecting an FPCB to the chip-on-glass type display, the adhesive layer and coverlay of the FPCB can be removed. In addition, the bonding layer between the FPCB and the display panel can be removed. In addition, the flexible circuit board includes a pad containing pure tin. The terminals of the display panel and the terminals of the printed circuit board are directly bonded to the pad. Accordingly, the thickness of the display is reduced, and process efficiency is improved.

[0056] The circuit board (3000) may include a rigid material. For example, the circuit board (3000) may include a printed circuit board (PCB). For example, the printed circuit board may include a main board.

[0057] The above display panel (2000) and the above circuit board (3000) are electrically connected by the flexible circuit board module (1000).

[0058] The above flexible circuit board module (1000) includes a plurality of flexible circuit boards (1100). The circuit board (300) and the display panel (2000) are electrically connected by the plurality of flexible circuit boards.

[0059] The flexible circuit board (1100) includes a plurality of circuit patterns. The flexible circuit board (1100) supplies power to at least one of the display panel (2000) and the circuit board (3000). In addition, the flexible circuit board (1100) transmits signals between the display panel (2000) and the circuit board (3000).

[0060] The above flexible circuit board (1100) is bent in one direction. Therefore, the above flexible circuit board (1100) includes a flexible material.

[0061] When the electrical characteristics of the flexible circuit board (1100) are reduced, power is not easily supplied to the display panel (2000) and the circuit board (3000). In addition, signals between the display panel (2000) and the circuit board (3000) do not easily travel.

[0062] Therefore, a flexible circuit board having improved electrical characteristics is described below.

[0063]

[0064] A flexible circuit board (1100) according to an embodiment is described with reference to FIGS. 3 to 8.

[0065] Figure 3 is a top view of a flexible circuit board without a protective layer. Figure 4 is a top view of a flexible circuit board with a protective layer.

[0066] Referring to FIGS. 3 and 4, the first flexible circuit board (1100) includes a substrate (100), a circuit pattern, and a protective layer (400).

[0067] The above-mentioned substrate (100) includes a first surface (1S) and a second surface (2S) opposite to the first surface (1S). The circuit pattern and the protective layer (400) are arranged on the first surface (1S).

[0068] The substrate (100) includes a cutting line (CL). The flexible circuit board (1100) is cut along the cutting line (CL). For example, the circuit pattern (200) and the protective layer (400) are arranged on the substrate (100). Subsequently, the substrate (100) is cut along the cutting line (CL). Accordingly, the test pattern and dummy pattern on the ineffective area of ​​the substrate can be removed.

[0069] The above description (100) includes a valid area and an ineffective area. In detail, the first surface (1S) includes the valid area and the ineffective area.

[0070] The above valid area and the above non-valid area are separated by the cutting line (CL). Specifically, the valid area is the area inside the cutting line. In addition, the non-valid area (UA) is the area outside the cutting line (CL).

[0071] The circuit pattern and the protective layer (400) are arranged in the effective area. In addition, a test pattern, a dummy pattern, and a sprocket hole (SH) are arranged in the ineffective area. The dummy pattern increases the strength of the substrate (100). In addition, the flexible circuit board (1100) is rolled or unrolled in a roll-to-roll manner by the sprocket hole (SH).

[0072] The substrate (100) includes a flexible material. For example, the substrate (100) may include polyimide (PI). However, the embodiment is not limited thereto. The substrate (100) may include a polymer material including polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Accordingly, the flexible circuit board can be used in various electronic devices, including curved display devices. For example, since the flexible circuit board has excellent flexibility, it can be applied to wearable electronic devices.

[0073] The substrate (100) may have a thickness of 20 μm to 45 μm. Specifically, the substrate (100) may have a thickness of 25 μm to 40 μm. More specifically, the substrate (100) may have a thickness of 30 μm to 35 μm. When the thickness of the substrate (100) exceeds 45 μm, the overall thickness of the flexible circuit board increases. Accordingly, the flexible characteristics of the flexible circuit board may be reduced. In addition, when the thickness of the substrate (100) is less than 20 μm, the strength of the flexible circuit board may be reduced.

[0074]

[0075] The circuit pattern and the protective layer (400) are disposed on the substrate (100). In detail, the circuit pattern and the protective layer (400) are disposed on the first surface (1S). In detail, the circuit pattern and the protective layer (400) are disposed on the effective area (AA).

[0076] The above protective layer (400) may include solder paste. For example, the above protective layer (400) may include solder paste containing a thermosetting resin, a thermoplastic resin, a filler, a curing agent, or a curing accelerator.

[0077] The above protective layer (400) has a set thickness. For example, the thickness of the above protective layer (400) may be 7 µm to 13 µm, 8 µm to 12 µm, or 9 µm to 11 µm.

[0078] The above protective layer (400) is directly disposed on the substrate (100) and the circuit pattern. In detail, the protective layer (400) is directly disposed on the substrate (100) and the circuit pattern without using a separate adhesive layer.

[0079] The above circuit pattern includes a plurality of wiring patterns (200) and a plurality of test patterns (300).

[0080] The above wiring pattern (200) includes a wiring portion (210) and a pad portion. The pad portion includes a first pad portion (221) and a second pad portion (222).

[0081] The wiring portion (210), the first pad portion (221), and the second pad portion (222) comprise the same material. In detail, the wiring portion (210), the first pad portion (221), and the second pad portion (222) are formed integrally.

[0082] The protective layer (400) is disposed on the wiring portion (210). The protective layer (400) is not disposed on the first pad portion (221) and the second pad portion (222). Accordingly, the first pad portion (221) is connected to the display panel (2000). In addition, the second pad portion (222) is connected to the circuit board (3000).

[0083] The wiring section (210) is arranged between the first pad section (221) and the second pad section (222). The wiring section (210) connects the first pad section (221) and the second pad section (222). The wiring section (210) is a pattern through which current flows. Accordingly, power is supplied to at least one of the display panel (2000) and the circuit board (3000) by the wiring section (210).

[0084] The above test pattern (300) is connected to the first pad portion (221). The test pattern (300) is removed by the cutting line (CL) during the process. Before cutting the substrate (100) along the cutting line (CL), the flexible circuit board (1100) is tested by the test pattern (300). Accordingly, defects in the flexible circuit board can be confirmed in advance.

[0085] The flexible circuit board has a set thickness. The thickness of the flexible circuit board is the sum of the thicknesses of the substrate, the circuit pattern, and the protective layer. The thickness of the flexible circuit board may be 45 μm to 56 μm, 48 μm to 55 μm, or 51 μm to 54 μm.

[0086]

[0087] The above wiring portions (210) have a pitch (P). The pitch (P) is the sum of the width (W) of the wiring portion and the spacing (S) between the wiring portions. The wiring portion includes a region where the width (W) and the spacing (S) are different. Specifically, the wiring portion includes a region where the width (W) is greater than the spacing (S).

[0088] For example, the spacing (S) may be 10 μm to 20 μm, 10 μm to 16 μm, or 10 μm to 13 μm. In addition, the width (W) may be 4 to 50 times, 4 to 49.5 times, or 4 to 49 times the spacing (S) of the wiring portion.

[0089] Accordingly, the area of ​​the wiring pattern (200) increases. In detail, the area of ​​the wiring pattern (200) placed in the effective area increases.

[0090] The resistance of the above wiring pattern (200) is inversely proportional to the area of ​​the wiring pattern (200). Therefore, as the width of the wiring portion (210) increases, the resistance of the wiring pattern (200) decreases. The area of ​​the wiring pattern (200) of the flexible circuit board increases. Therefore, the resistance of the flexible circuit board (1000) decreases.

[0091] Conventional FPCBs have wiring sections with identical widths and spacings. Consequently, the area of ​​the wiring pattern arranged within the effective area is limited. However, in the embodiment, the width of the wiring sections is formed to be greater than the spacing between the wiring sections. In other words, compared to conventional FPCB wiring patterns, the pitch remains the same, but the width can be increased.

[0092] Accordingly, the resistance of the flexible circuit board decreases. Therefore, the flexible circuit board easily supplies power to the display panel (2000) and the printed circuit board (3000). In addition, signals for moving the display panel (2000) and the printed circuit board (3000) are easily transmitted by the flexible circuit board.

[0093]

[0094] The width (W) of the above wiring portion and the spacing (S) of the above wiring portion may vary. In detail, the wiring portion may include a plurality of regions with different widths and spacings. The wiring portion (210) may be divided into a first region (1A), a second region (2A), and a third region (3A) depending on the location.

[0095] Referring to FIGS. 3 and 5 to 7, the first region (1A) is connected to the second region (2A) and the third region (3A). The first region (1A) is bent and extends from the second region (2A). In addition, the second region (2A) is connected to the first region (1A) and the first pad portion (221). In addition, the third region (3A) is connected to the first region (1A) and the second pad portion (222). The third region (3A) is bent and extends from the first region (1A).

[0096] The first region (1A) has a first width (W1) and a first spacing (S1). The second region (2A) has a second width (W2) and a second spacing (S2). The third region (3A) has a third width (W3) and a third spacing (S3).

[0097] The first width (W1), the second width (W2), and the third width (W3) are different. Specifically, the first width (W1) is greater than the second width (W2) and the third width (W3). The length of the first region (1A) is greater than the lengths of the second region (2A) and the third region (3A). In addition, the first region (1A) is a region through which power is supplied to the display panel (2000) and the printed circuit board (3000). Therefore, the width of the first region (1A) is formed to be the largest. Accordingly, the resistance of the first region (1A) is reduced. As a result, the wiring pattern (200) can easily supply power.

[0098] The above second width (W2) and the above third width (W3) are different.

[0099] The second region (2A) is an region connected to the first pad portion (221). Therefore, the width of the second region (2A) is the same as the width of the first pad portion (221). The first pad portion (221) is connected to a terminal of the display panel. Accordingly, the width of the first pad portion (221) varies depending on the size of the terminal of the display panel.

[0100] In addition, the third region (3A) is an region connected to the second pad portion (222). Therefore, the width of the third region (3A) is the same as the width of the second pad portion (222). The second pad portion (222) is connected to a terminal of the printed circuit board. Accordingly, the width of the second pad portion (222) varies depending on the size of the terminal of the printed circuit board.

[0101] For example, the second width (W2) may be greater than the third width (W3).

[0102]

[0103] The first interval (S1), the second interval (S2), and the third interval (S3) are different. Specifically, the first interval (S1) is smaller than the second interval (S2) and the third interval (S3). The length of the first region (1A) is longer than the lengths of the second region (2A) and the third region (3A). In addition, the first region (1A) is a region to which power is supplied to the display panel (2000) and the printed circuit board (3000). Therefore, the interval of the first region (1A) is formed to be the smallest. As a result, the width of the first region (1A) increases at the same pitch. Therefore, the resistance of the first region (1A) decreases. As a result, the wiring pattern (200) can easily supply power.

[0104] The above second interval (S2) and the above third interval (S3) are different.

[0105] The second region (2A) is an area connected to the first pad portion (221). Therefore, the spacing of the second region (2A) is the same as the spacing of the first pad portion (221). The first pad portion (221) is connected to the terminal of the display panel. Accordingly, the spacing of the first pad portion (221) varies depending on the spacing of the terminal of the display panel.

[0106] In addition, the third region (3A) is an area connected to the second pad portion (222). Therefore, the spacing of the third region (3A) is the same as the spacing of the second pad portion (222). The second pad portion (222) is connected to the terminal of the printed circuit board. Accordingly, the spacing of the second pad portion (222) varies depending on the spacing of the terminal of the printed circuit board.

[0107] For example, the second interval (S2) may be greater than the third interval (S3).

[0108] The first width (W1) and the first spacing (S1) are different. Specifically, the first width (W1) is greater than the first spacing (S1). That is, the first region (1A) is the region with the largest width in the wiring section. Furthermore, the first region (1A) is the region with the smallest spacing in the wiring section.

[0109] The above first region (1A) is the longest region in the wiring section. Therefore, the current flowing through the wiring pattern moves most in the first region (1A). Accordingly, the first width (W1) is formed to be larger than the first interval (S1).

[0110] For example, the first spacing (S1) may be 10 μm to 20 μm, 10 μm to 16 μm, or 10 μm to 13 μm. In addition, the first width (W1) may be 4 to 50 times, 4 to 49.5 times, or 4 to 49 times the first spacing (S).

[0111] Since the first width (W1) is greater than the first interval (S1), the resistance of the first region (1A) decreases. Accordingly, the current and the signal easily move to the display panel (2000) and the printed circuit board (3000) through the first region (1A).

[0112]

[0113] The second width (W2) and the second spacing (S2) are the same or similar. For example, the second width (W2) is 0.99 to 1.01 times the second spacing (S2). In addition, the third width (W3) and the third spacing (S3) are the same or similar. For example, the third width (W3) is 0.99 to 1.01 times the third spacing (S3).

[0114] The second region (2A) is an region connected to the first pad portion (221). In order to prevent short circuiting of adjacent first pad portions (221), the second gap (S2) has a set size.

[0115] In addition, the third region (3A) is an region connected to the second pad portion (222). In order to prevent short circuiting of adjacent second pad portions (222), the third gap (S3) has a set size.

[0116] Accordingly, the second width (W2) and the second spacing (S2) are the same or similar, and the third width (W3) and the third spacing (S3) are the same or similar. Accordingly, the pad portions can be spaced apart from each other while ensuring sufficient widths of the first pad portions (221) and the second pad portions (222).

[0117] Accordingly, the reliability of the flexible circuit board is improved.

[0118]

[0119] Referring to Fig. 6, the wiring pattern (200) includes a cutting pattern (CP). The cutting pattern (CP) is positioned between the first pad portion (221) and the test pattern (300).

[0120] The width (W4) of the above cutting pattern is smaller than the widths (W1, W2, W3) of the wiring portion. Specifically, the width (W4) of the above cutting pattern is smaller than the widths (W1, W2, W3) of the first region, the second region, and the third region. In addition, the width (W4) of the above cutting pattern is smaller than the width (W5) of the first pad portion and the width (W6) of the second pad portion.

[0121] The above-described cutting pattern (CP) is a pattern cut by the cutting line (CL). The width (W4) of the cutting pattern is formed smaller than that of other regions. Therefore, the flexible circuit board is easily cut by the cutting pattern (CP). In addition, impurities such as debris generated when cutting the flexible circuit board are reduced. Accordingly, impurities can be prevented from being absorbed into the first pad portion. In addition, the intensity of the laser required when cutting the flexible circuit board is reduced. Therefore, when cutting the flexible circuit board, damage to the flexible circuit board can be prevented.

[0122]

[0123] Fig. 8 is a drawing illustrating a cutting pattern (CP) according to another embodiment.

[0124] Referring to Fig. 8, the wiring pattern (200) includes a plurality of cutting patterns (CP). Fig. 8 illustrates two cutting patterns. However, the embodiment is not limited thereto. The cutting pattern may include three or more cutting patterns.

[0125] The above cutting pattern includes a first cutting pattern (CP1) and a second cutting pattern (CP2). The first cutting pattern (CP1) and the second cutting pattern (CP2) are arranged between the first pad portion (221) and the test pattern (300).

[0126] The first cutting pattern (CP1) and the second cutting pattern (CP2) are spaced apart. The width (W4') of the first cutting pattern (CP1) and the second cutting pattern (CP2) is smaller than the widths (W1, W2, W3) of the first region, the second region, and the third region. In addition, the width (W4) of the cutting pattern is smaller than the width (W5) of the first pad portion and the width (W6) of the second pad portion.

[0127] The first cutting pattern (CP1) and the second cutting pattern (CP2) are patterns cut by the cutting line (CL). The width (W4') of the first cutting pattern (CP1) and the second cutting pattern (CP2) is formed to be smaller than that of other regions. Therefore, the flexible circuit board is easily cut by the first cutting pattern (CP1) and the second cutting pattern (CP2). In addition, the cutting pattern includes a plurality of cutting patterns. Accordingly, even if a crack occurs in one of the cutting patterns, the first pad portion and the test pattern can be connected by the other cutting patterns.

[0128]

[0129] The above wiring pattern may have various layer structures.

[0130] Figures 9 to 12 are various cross-sectional views taken along the AA' area of ​​Figure 4.

[0131] Referring to Fig. 9, the wiring pattern (200) may be formed in multiple layers. The wiring portion (210), the first pad portion (221), and the second pad portion (222) may include a first metal layer (510) and a second metal layer (520).

[0132] The first metal layer (510) may be a seed layer of the wiring pattern (200). For example, the first metal layer (510) may include copper (Cu) and may be formed through electroless plating.

[0133] The second metal layer (520) may be a plating layer. For example, the second metal layer (520) may be a plating layer formed by electrolytic plating using the first metal layer (510) as a seed layer.

[0134] The thickness of the first metal layer (510) is smaller than the thickness of the second metal layer (520).

[0135] For example, the thickness of the first metal layer (510) may be 0.7 μm to 2 μm. Additionally, the thickness of the second metal layer (520) may be 8 μm to 10 μm.

[0136] The first metal layer (510) and the second metal layer (520) include the same metal. For example, the first metal layer (510) and the second metal layer (520) may include copper (Cu).

[0137] Additionally, a bonding layer (530) is disposed on the second metal layer (520). The bonding layer (530) may be disposed on at least one of the side surface of the first metal layer (510), the side surface of the second metal layer (520), and the upper surface of the second metal layer (520).

[0138] The above bonding layer (530) may include a metal. In detail, the above bonding layer (530) may include tin (Sn).

[0139] The above bonding layer (530) may be formed to a thickness of 0.3 μm to 0.7 μm. The content of tin in the bonding layer (530) may increase as it extends from the lower surface to the upper surface.

[0140] That is, the bonding layer (530) is in contact with the second metal layer (520). Therefore, the content of tin in the bonding layer (530) increases from the lower surface to the upper surface, and the content of copper decreases.

[0141] Accordingly, only pure tin can remain in the thickness range of 0.1 µm to 0.3 µm on the upper surface of the bonding layer (530).

[0142] By the bonding layer (530), the first pad portion (221) and the second pad portion (222) can be easily connected to the terminal of the display panel and the terminal of the printed circuit board. That is, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer where pure tin remains is melted. As a result, the pad portion, the terminal of the display panel, and the terminal of the circuit board are easily bonded.

[0143] The thickness of the above wiring pattern (200) may be 8 µm to 12 µm. For example, the thickness of the above wiring pattern (200) may be 9 µm to 11 µm.

[0144] If the thickness of the wiring pattern (200) is less than 8 µm, the resistance of the wiring pattern (200) may increase. If the thickness of the wiring pattern (200) exceeds 12 µm, the folding reliability of the flexible circuit board may decrease.

[0145] The above wiring pattern (200) may further include a buffer layer (540). The buffer layer (540) is disposed between the substrate (100) and the first metal layer (510). The adhesion between the substrate (100) and the first metal layer (510) is improved by the buffer layer (540).

[0146] The above buffer layer (540) may be formed in multiple layers. Specifically, a first buffer layer (541) and a second buffer layer (542) on the first buffer layer (541) may be disposed on the substrate (100). Accordingly, the first buffer layer (541) is in contact with the substrate (100). In addition, the second buffer layer (542) is in contact with the first metal layer (510).

[0147] The first buffer layer (541) may include a material having good adhesion to the substrate (100). For example, the first buffer layer (541) may include nickel (Ni). In addition, the second buffer layer (542) may include a material having good adhesion to the first metal layer (510). For example, the second buffer layer (542) may include chromium (Cr).

[0148] The above buffer layer (540) may have a thin film thickness in nanometer units. For example, the thickness of the buffer layer (540) may be 20 nm or less.

[0149] The adhesion between the above-mentioned substrate (100) and the first metal layer is improved by the buffer layer (250). As a result, peeling of the wiring pattern is prevented.

[0150]

[0151] Referring to FIGS. 3 and 4, the flexible circuit board (1100) includes a bending area (BA). The bending area (BA) is arranged in the second area (2A). That is, one area of ​​the second area (2A) is bent. That is, the second area (2A) includes a bending area.

[0152] Accordingly, stress may be generated in the second region (2A). In addition, a region of the wiring portion (210) may overlap with the bending region. Accordingly, if the thickness of a region of the first wiring portion (210) overlapping with the bending region is thick, the bending characteristics may be reduced.

[0153] Additionally, a crack may be formed in a region of the wiring portion (210) that overlaps the bending region due to the stress. Accordingly, the layer structure of the wiring portion may be different from the layer structure of the pad pattern.

[0154] Alternatively, the layer structure of one area of ​​the wiring portion overlapping the bending area may be different from the layer structure of another area.

[0155]

[0156] Referring to FIG. 10, a flexible circuit board according to another embodiment is described.

[0157] Referring to FIG. 10, the bonding layer (530) may include a plurality of bonding layers. For example, the bonding layer (530) may include a first bonding layer (531) and a second bonding layer (532).

[0158] In detail, the first wiring portion (210), the first pad portion (221), and the second pad portion (222) may include the first bonding layer (531). In addition, the first pad portion (221) and the second pad portion (222) may include the second bonding layer (532).

[0159] The first bonding layer (531) and the second bonding layer (532) include a metal. The first bonding layer (531) and the second bonding layer (532) may include the same metal. In detail, the first bonding layer (531) and the second bonding layer (532) may include tin (Sn).

[0160] The thickness of the first bonding layer (531) and the thickness of the second bonding layer (532) are different. Specifically, the thickness of the first bonding layer (531) is smaller than the thickness of the second bonding layer (532).

[0161] For example, the thickness of the first bonding layer (531) may be 0.02 μm to 0.06 μm. Additionally, the thickness of the second bonding layer (532) may be 0.2 μm to 0.6 μm.

[0162] Accordingly, the thickness of the bonding layer disposed on the wiring portion becomes smaller than the thickness of the bonding layer disposed on the pad portion. That is, the bonding layer disposed on the wiring portion is formed with a thin film thickness.

[0163] The second region (2A) overlaps with the wiring portion. Furthermore, only the first bonding layer is disposed on the wiring portion. Therefore, the flexible circuit board can be easily bent in the second region (2A). Furthermore, when bending the flexible circuit board, cracks can be prevented from forming in the bonding layer in the region overlapping the bending region.

[0164]

[0165] Referring to FIG. 11, a flexible circuit board according to another embodiment is described.

[0166] Referring to FIG. 11, the wiring pattern (200) may include the first bonding layer (531) and the second bonding layer (532).

[0167] The first bonding layer (531) is disposed on the second metal layer (520). Specifically, the first bonding layer (531) is disposed on the side surface of the first metal layer (510) and the upper surface and side surface of the second metal layer (520). The first bonding layer (531) is disposed on a portion of the second metal layer (520). The second bonding layer (531) is disposed while partially exposing the second metal layer (520). As a result, an open area (OA) is formed on the second metal layer (520).

[0168] The open area (OA) is arranged in an area corresponding to the second area (2A). The open area (OA) may be the entire area of ​​the second area (2A). Alternatively, the open area (OA) may be a portion of the second area (2A).

[0169] A protective layer (400) is disposed on the first bonding layer (531). The protective layer (400) is disposed so as to fill the interior of the open area (OA). Accordingly, the protective layer (400) is disposed within the interior of the open area (OA).

[0170] The second bonding layer (532) is disposed on the first bonding layer (531). The second bonding layer (532) is disposed on the upper surface and side surfaces of the first bonding layer (531). The second bonding layer (532) is not disposed on an area corresponding to the open area (OA).

[0171] The wiring section (210) of the second region (2A) includes an open area (OA). In addition, a protective layer (400) containing a resin material is arranged inside the open area (OA).

[0172] Accordingly, the flexible circuit board can be easily bent. In addition, when bending the flexible circuit board, cracks can be prevented from forming in the bonding layer due to the open area. That is, the second area includes the open area, and the bonding layer is not disposed in the open area. Therefore, when bending the flexible circuit board, cracks can be prevented from forming in the bonding layer due to stress.

[0173]

[0174] Referring to FIG. 12, a flexible circuit board according to another embodiment is described.

[0175] Referring to FIG. 12, the wiring pattern (200) may include the first bonding layer (531) and the second bonding layer (532).

[0176] The first bonding layer (531) is disposed on the second metal layer (520). Specifically, the first bonding layer (531) is disposed on the side surface of the first metal layer (510) and the upper surface and side surface of the second metal layer (520). The first bonding layer (531) is disposed on a portion of the second metal layer (520). The second bonding layer (531) is disposed while partially exposing the second metal layer (520). As a result, an open area (OA) is formed on the second metal layer (520).

[0177] The open area (OA) is arranged in an area corresponding to the second area (2A). The open area (OA) may be the entire area of ​​the second area (2A). Alternatively, the open area (OA) may be a portion of the second area (2A).

[0178] A first protective layer (410) is disposed on the open area (OA). The first protective layer (410) is disposed inside the open area (OA). The first protective layer (410) is in contact with the upper surface of the second metal layer (520). Accordingly, the first protective layer (410) is disposed inside the open area (OA).

[0179] The second bonding layer (532) is disposed on the first bonding layer (531). The second bonding layer (532) is disposed on the upper surface and side surfaces of the first bonding layer (531).

[0180] A second protective layer (420) is disposed on the first bonding layer (531). The second protective layer (420) is disposed on the first protective layer (410). The second protective layer (420) overlaps the open area (OA).

[0181] The above wiring section (210) includes an open area (OA). In addition, the first protective layer (410) and the second protective layer (420) containing a resin material are arranged inside the open area (OA).

[0182] Accordingly, the flexible circuit board can be easily bent. In addition, when bending the flexible circuit board, cracks can be prevented from being formed in the bonding layer due to the open area. That is, the second area includes the open area, and the bonding layer is not disposed in the open area. In addition, two protective layers are disposed in the open area. Therefore, when bending the flexible circuit board, cracks can be prevented from being formed in the bonding layer due to stress.

[0183]

[0184] Figures 13 to 20 are cross-sectional views of cases where the flexible circuit board has the layer structure of Figures 9 to 12.

[0185] Figures 13 and 14 are cross-sectional views of a case having the layer structure of Figure 9. Figures 15 and 16 are cross-sectional views of a case having the layer structure of Figure 10. Figures 17 and 18 are cross-sectional views of a case having the layer structure of Figure 11. Figures 19 and 20 are cross-sectional views of a case having the layer structure of Figure 12.

[0186] Figures 13, 15, 17, and 19 are cross-sectional views of areas other than the second area, and Figures 14, 16, 18, and 20 are cross-sectional views of the second area.

[0187] Referring to FIGS. 13 and 14, the layer structures of the second region and regions other than the second region may be identical. Specifically, the bonding layer (530) and the protective layer (400) may be disposed on the second metal layer (520) in the second region and regions other than the second region.

[0188] Referring to FIGS. 15 and 16, the layer structures of the second region and regions other than the second region may be the same. Specifically, the first bonding layer (531) and the protective layer (400) may be disposed on the second metal layer (520) in the second region and regions other than the second region. Specifically, the thickness of the first bonding layer (531) may be smaller than the thickness of the second bonding layer (532), and the second bonding layer (532) may be disposed only on the first pad portion (221) and the second pad portion (222b).

[0189] Referring to FIGS. 17 and 18, the layer structures of the second region and regions other than the second region can be addressed. Referring to FIG. 17, the region other than the second region includes only the region where the first bonding layer (531) and the protective layer (400) are disposed on the second metal layer (262).

[0190] Also, referring to FIG. 18, when the open area (OA) is a portion of the second area (2A), the second area includes an area where the protective layer (400) is disposed on the second metal layer (520) and an area where the first bonding layer (531) and the protective layer (400) are disposed on the second metal layer (520). Alternatively, when the open area (OA) is the entire area of ​​the second area (2A), the second area includes only an area where the protective layer (400) is disposed on the second metal layer (520).

[0191] In detail, the thickness of the first bonding layer (531) and the thickness of the second bonding layer (532) are the same or similar, and the first bonding layer (531) can be disposed on an area other than the second area. In addition, the second bonding layer (532) can be disposed only on the first pad portion (221) and the second pad portion (222).

[0192]

[0193] Referring to FIGS. 19 and 20, the layer structures of the second region and regions other than the second region can be addressed. Referring to FIG. 19, the region other than the second region includes only the region where the first bonding layer (531) and the second protective layer (420) are disposed on the second metal layer (520).

[0194] Also, referring to FIG. 20, when the open area (OA) is a portion of the second area (2A), the second area includes an area where the first protective layer (410) and the second protective layer (420) are disposed on the second metal layer (520) and an area where the first bonding layer (531) and the second protective layer (420) are disposed on the second metal layer (520). Alternatively, when the open area (OA) is the entire area of ​​the second area (2A), the second area includes only an area where the first protective layer (410) and the second protective layer (420) are disposed on the second metal layer (520). In detail, the thickness of the first bonding layer (531) and the thickness of the second bonding layer (532) are the same or similar, and the first bonding layer (531) can be disposed on an area other than the second region. In addition, the second bonding layer (532) can be disposed only on the first pad portion (221) and the second pad portion (222). In addition, the second protective layer (420) is disposed on the second region and an area other than the second region.

[0195]

[0196] Since the above flexible circuit board module is flexible, it can be used in various electronic devices.

[0197] For example, referring to FIG. 21, the flexible circuit board module can be applied to a flexible touch device that can be bent. Accordingly, a user can bend or fold the touch device by hand.

[0198] Referring to FIG. 22, the flexible circuit board module can be applied to a wearable touch device including a curved display.

[0199] Referring to FIGS. 23 and 24, the flexible circuit board module can be applied to various electronic devices having a display portion, such as a TV, a monitor, or a laptop. The flexible circuit board module can also be used in an electronic device having a curved display portion.

[0200]

[0201] The features, structures, effects, etc. described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0202] In addition, although the above description focuses on embodiments, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. A substrate comprising a first side and a second side opposite to the first side; A plurality of wiring patterns arranged on the first surface; and Including a protective layer disposed on the above wiring pattern, The above wiring pattern is, A first pad portion connected to the display panel; A second pad portion connected to the circuit board; and It includes a wiring section connecting the first pad section and the second pad section, A flexible circuit board including an area in which the width of the wiring portion is greater than the spacing between the wiring portions.

2. In paragraph 1, A flexible circuit board having a width of the above wiring section that is 4 to 50 times the spacing.

3. In paragraph 1, The above wiring section is a flexible circuit board including a plurality of areas with different widths.

4. In paragraph 3, The above wiring section includes a first region, a second region, and a third region, The first region is connected to the second region and the third region, The second region is connected to the first region and the first pad portion, The third region is connected to the first region and the second pad portion, The first region has a first width and a first spacing, The second region has a second width and a second spacing, The third region has a third width and a third spacing, A flexible circuit board having a first width greater than the second width and the third width.

5. In paragraph 4, The above first region is bent and extended from the above second region, The third region is extended and bent from the first region, A flexible circuit board wherein the length of the first region is longer than the lengths of the second region and the third region.

6. In paragraph 5, A flexible circuit board wherein the first gap is smaller than the second gap and the third gap.

7. In paragraph 5, The above first width is greater than the above first interval, The second width is 0.99 to 1.01 times the second interval, A flexible circuit board wherein the third width is 0.99 to 1.01 times the third gap.

8. In paragraph 1, Further comprising a test pattern connected to the first pad portion, At least one cutting pattern is arranged between the first pad portion and the test pattern, A flexible circuit board in which the width of the above cutting pattern is smaller than the width of the above wiring portion.

9. In paragraph 8, A flexible circuit board in which the width of the above cutting pattern is smaller than the width of at least one of the first pad portion and the second pad portion.

10. In paragraph 8, The above cutting pattern is a flexible circuit board including a plurality of cutting patterns spaced apart from each other.

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