Flexible circuit board module and electronic device including same

Abstract

The flexible circuit board according to the present invention comprises: a substrate comprising 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 plurality of wiring patterns, where each of the plurality of wiring patterns includes: a first pad portion connected to the display panel; a second pad portion connected to the circuit board; and a wiring portion connecting the first pad portion and the second pad portion, and wherein the wiring portion includes a region in which a width of the wiring portion is larger than an interval between the wiring portions.

Description

Technical Field

[0001] The embodiments relate to a flexible circuit board module and an electronic device including the flexible circuit board module. Background Technology

[0002] Recently, electronic products have been becoming thinner. Furthermore, electronic products are becoming smaller and lighter. Therefore, it is necessary to install semiconductor chips at high density within narrow areas of electronic products.

[0003] Chip on Glass (COG) is a display panel in which the driver chip is directly mounted on the glass substrate.

[0004] The chip on the glass is connected to a printed circuit board, such as a motherboard. The chip on the glass and the printed circuit board are connected by connectors.

[0005] Connectors may include flexible circuit boards. For example, a connector may include an FPCB (flexible printed circuit board).

[0006] FPCB includes a substrate and a circuit pattern on the substrate. Additionally, a coverlay is provided on the circuit pattern. The coverlay protects the circuit pattern. The coverlay is bonded by an adhesive layer.

[0007] Therefore, the thickness of the FPCB increases due to the adhesive layer and the cover layer. Furthermore, due to the cover layer, the change in elongation of the FPCB during the thermoforming process may increase.

[0008] Furthermore, FPCBs ensure that the linewidth and spacing of the circuit patterns are uniform. Therefore, the area of ​​the circuit patterns disposed on the substrate is limited. Consequently, the size of the FPCB may increase.

[0009] Therefore, there is a need for flexible circuit board modules with new structures that can solve the above problems, and electronic devices that include such flexible circuit board modules.

[0010] As a patent involving flexible circuit board modules, Korean registered patent KR10-0618898 (2006.09.01) was disclosed. Summary of the Invention

[0011] Technical issues

[0012] The embodiment provides a flexible circuit board module with improved electrical connectivity characteristics.

[0013] The embodiment provides a flexible circuit board module with a small size.

[0014] Technical solution

[0015] The flexible circuit board according to an embodiment includes: a substrate, the 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 plurality of wiring patterns, wherein the plurality of wiring patterns include: a first pad portion connected to a display panel; a second pad portion connected to a circuit board; and wiring portions connecting the first pad portion and the second pad portion, wherein the wiring portion includes a region whose width is greater than the interval between the wiring portions.

[0016] Beneficial effects

[0017] The flexible circuit board module according to an embodiment includes multiple flexible circuit boards.

[0018] The flexible circuit board includes multiple wiring patterns. The wiring pattern includes a wiring section, a first pad section, and a second pad section.

[0019] The cabling section comprises multiple areas. In any one of these areas, the width of the cabling section may be greater than the spacing between cabling sections.

[0020] The resistance of a wiring pattern is inversely proportional to its area. Therefore, as the width of the wiring increases, the resistance of the wiring pattern decreases. In flexible circuit boards, the area of ​​the wiring pattern increases. Therefore, the resistance of the flexible circuit board decreases.

[0021] In conventional FPCBs, the width of the wiring portions is smaller than the spacing between them. Therefore, the area of ​​the wiring pattern within the effective region is limited. However, in this embodiment, the width of the wiring portions is larger than the spacing between them. That is, compared to the wiring patterns of conventional FPCBs, the spacing is the same, but the width can be increased.

[0022] Therefore, the resistance of the flexible circuit board is reduced. Consequently, the flexible circuit board can easily supply power to the display panel and printed circuit board. Furthermore, signals moving within the display panel and printed circuit board can easily travel through the flexible circuit board.

[0023] Furthermore, flexible circuit boards do not include separate adhesive layers and separate cover layers. Therefore, the thickness of the flexible circuit board is reduced. Additionally, differences in elongation during folding due to the cover layer can be prevented.

[0024] Furthermore, when bonding conventional FPCBs to display panels, ACF (Anisotropic Conductive Film) is used. That is, a separate bonding layer is required. However, flexible circuit boards are formed with pads containing only pure tin, and the terminals of the display panel are bonded to the terminals of the printed circuit board. Specifically, the bonding is performed by melting the tin using heat and pressure. Therefore, the thickness of the display is reduced. Attached Figure Description

[0025] Figure 1 This is a plan view of an electronic device according to an embodiment.

[0026] Figure 2 This is a diagram illustrating the connection relationships of an electronic device according to an embodiment.

[0027] Figure 3 and Figure 4 This is a top view of the flexible circuit board according to an embodiment.

[0028] Figure 5 yes Figure 3 A magnified view of region A.

[0029] Figure 6 yes Figure 3 A magnified view of region B.

[0030] Figure 7 yes Figure 3 A magnified view of region C.

[0031] Figure 8 This is a view used to illustrate a cutting pattern of another embodiment.

[0032] Figures 9 to 12 By dissecting Figure 4 The sectional view obtained from region A-A'.

[0033] Figure 13 and Figure 14 They are respectively through dissection Figure 4 The sectional views obtained from regions B-B' and C-C'.

[0034] Figure 15 and Figure 16 They are respectively through dissection Figure 4 The sectional views obtained from regions B-B' and C-C'.

[0035] Figure 17 and Figure 18 They are respectively through dissection Figure 4 The sectional views obtained from regions B-B' and C-C'.

[0036] Figure 19 and Figure 20 They are respectively through dissection Figure 4 The sectional views obtained from regions B-B' and C-C'.

[0037] Figures 21 to 24 This is a view of an electronic device according to an embodiment. Detailed Implementation

[0038] In the following description, embodiments of the present disclosure will be illustrated in detail with reference to the accompanying drawings. However, the concept and scope of the present disclosure are not limited to the portion of the described embodiments and may be implemented in various other forms, and one or more components in the embodiments may be selectively combined and rearranged within the concept and scope of the present disclosure.

[0039] Furthermore, unless otherwise explicitly defined and described, the terms used in the embodiments of this disclosure (including technical and scientific terms) may be interpreted as having the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains, and terms such as those defined in common dictionaries may be interpreted as having a meaning consistent with their meaning in the context of the relevant field.

[0040] Furthermore, the terminology used in the embodiments of this disclosure is for describing embodiments and is not intended to limit this disclosure. In this specification, unless specifically stated in the phrase, the singular form may also include the plural form, and when described as “at least one (or more) of A (and), B and C”, it may include at least one of all combinations that can be combined with A, B and C.

[0041] Furthermore, in describing the elements of embodiments of this disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are used only to distinguish components from other components, and these terms are not limited to the nature, order, or sequence of components.

[0042] Furthermore, when a component is described as being “connected,” “joined,” or “in contact” with another component, this may include not only cases where the component is directly “connected,” “joined,” or “in contact” with other components, but also cases where the component is “connected,” “joined,” or “in contact” with another component through which the component is connected.

[0043] Furthermore, when described as being formed or set “above” or “below” each component, “above” or “below” can include not only cases where two components are directly connected to each other, but also cases where one or more other components are formed or set between two components.

[0044] Furthermore, when expressed as "above" or "below", it can include not only the upward direction based on a component, but also the downward direction based on a component.

[0045] Furthermore, in the following description, the first direction 1D is defined as the length direction (vertical direction) of the flexible circuit board. Additionally, the second direction 2D is defined as the width direction (horizontal direction) of the flexible circuit board.

[0046] In the following description, a flexible circuit board module and an electronic device including the flexible circuit board module according to an embodiment will be described with reference to the accompanying drawings.

[0047] Reference Figure 1 and Figure 2 The electronic device 10 includes a flexible circuit board module 1000, a display panel 2000, and a circuit board 3000.

[0048] The display panel 2000 is connected to the circuit board 3000. Specifically, the display panel 2000 and the circuit board 3000 are electrically connected via the flexible circuit board module 1000.

[0049] Display panel 2000 may include display panels that require high power. For example, display panels may be used in electronic devices such as laptops.

[0050] The display panel 2000 includes a first panel 2100, a second panel 2200, multiple light-emitting diodes 2300, and a chip CH.

[0051] At least one of the first panel 2100 and the second panel 220 includes glass.

[0052] The second panel 2200 can be disposed on the first panel 2100. The flexible circuit board module 1000 can be connected to at least one of the first panel 2100 and the second panel 2200.

[0053] The light-emitting diode 2300 may include a miniature LED. The light-emitting diode 2300 may be disposed on either the first panel 2100 or the second panel 2200. For example, the light-emitting diode 2300 may be disposed on the upper part of the second panel 2200. The flexible circuit board module 1000 is connected to the second panel 2200.

[0054] Alternatively, the light-emitting diode 2300 can be disposed on the lower part of the first panel 2100. The flexible circuit board module 1000 is connected to the second panel 2200. Therefore, the area of ​​the light-emitting diode 2300 can be increased.

[0055] The chip CH can be located on either the first panel 2100 or the second panel 2200. For example, the chip CH can be located on the second panel 2200. The chip CH can be a driver IC.

[0056] For example, display panel 2000 can be a glass panel on which chips are mounted. That is, display panel 200 is a chip-on-glass (COG) type.

[0057] The driver IC chip is directly mounted on the display panel. That is, the driver IC chip is formed on a chip-on-glass display panel. Therefore, since a separate chip-on-film (COF) is not required, the manufacturing cost of the display is reduced. Furthermore, because the chip on the COF is directly mounted on the display panel, the thickness of the display is reduced. Additionally, when attaching the FPCB to a chip-on-glass display, the adhesive layer and cover layer of the FPCB can be removed. Furthermore, the bonding layer between the FPCB and the display panel can be removed. Moreover, the flexible circuit board includes pads containing pure tin. The terminals of the display panel and the terminals of the printed circuit board are directly bonded to the pads. Therefore, the thickness of the display is reduced, and process efficiency is improved.

[0058] Circuit board 3000 may include a rigid material. For example, circuit board 3000 may include a printed circuit board (PCB). For example, a printed circuit board may include a motherboard.

[0059] The display panel 2000 and the circuit board 3000 are electrically connected via the flexible circuit board module 1000.

[0060] The flexible circuit board module 1000 includes multiple flexible circuit boards 1100. The circuit board 300 and the display panel 2000 are electrically connected through the multiple flexible circuit boards.

[0061] The flexible circuit board 1100 includes multiple 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.

[0062] The flexible circuit board 1100 is bent in one direction. Therefore, the flexible circuit board 1100 includes a flexible material.

[0063] If the electrical characteristics of the flexible circuit board 1100 are degraded, it will be difficult to supply power to the display panel 2000 and the circuit board 3000. In addition, signals between the display panel 2000 and the circuit board 3000 will not be easily transferred.

[0064] Therefore, the following section will describe a flexible circuit board with improved electrical characteristics.

[0065] Reference Figures 3 to 8 A flexible circuit board 1100 according to an embodiment is described.

[0066] Figure 3 This is a top view of a flexible circuit board, where the protective layer is not shown. Figure 4 This is a top view of a flexible circuit board, showing the protective layer.

[0067] Reference Figure 3 and Figure 4The first flexible circuit board 1100 includes a substrate 100, a circuit pattern, and a protective layer 400.

[0068] The substrate 100 includes a first surface 1S and a second surface 2S opposite to the first surface 1S. A circuit pattern and a protective layer 400 are disposed on the first surface 1S.

[0069] The substrate 100 includes a dicing line CL. The flexible circuit board 1100 is cut along the dicing line CL. For example, a circuit pattern 200 and a protective layer 400 are disposed on the substrate 100. Then, the substrate 100 is cut along the dicing line CL. Therefore, test patterns and dummy patterns on non-functional areas of the substrate can be removed.

[0070] The substrate 100 includes effective regions and ineffective regions. Specifically, the first surface 1S includes effective regions and ineffective regions.

[0071] The valid and invalid regions are separated by the cutting line CL. Specifically, the valid region is the area inside the cutting line. Furthermore, the invalid region UA ​​is the area outside the cutting line CL.

[0072] Circuit patterns and a protective layer 400 are disposed in the effective area. Additionally, test patterns, dummy patterns, and sprocket holes SH are disposed in the non-effective area. The dummy patterns increase the strength of the substrate 100. Furthermore, the flexible circuit board 1100 is wound or unwound in a roll-to-roll manner through the sprocket holes SH.

[0073] The substrate 100 comprises a flexible material. For example, the substrate 100 may comprise polyimide (PI). However, the embodiments are not limited thereto. The substrate 100 may comprise a polymer material comprising polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Therefore, the flexible circuit board can be used in various electronic devices, including curved display devices. For example, due to its excellent flexibility, the flexible circuit board can be applied to wearable electronic devices.

[0074] The substrate 100 can have a thickness of 20 μm to 45 μm. More specifically, the substrate 100 can have a thickness of 25 μm to 40 μm. More specifically, the substrate 100 can have a thickness of 30 μm to 35 μm. If the thickness of the substrate 100 exceeds 45 μm, the total thickness of the flexible circuit board increases. Therefore, the flexibility of the flexible circuit board may decrease. Furthermore, if the thickness of the substrate 100 is less than 20 μm, the strength of the flexible circuit board may decrease.

[0075] A circuit pattern and a protective layer 400 are disposed on the substrate 100. Specifically, the circuit pattern and the protective layer 400 are disposed on the first surface 1S. Specifically, the circuit pattern and the protective layer 400 are disposed on the effective area AA.

[0076] Protective layer 400 may include solder paste. For example, protective layer 400 may include solder paste comprising a thermosetting resin, a thermoplastic resin, a filler, a curing agent, or a curing accelerator.

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

[0078] The 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 circuit pattern includes multiple wiring patterns 200 and multiple test patterns 300.

[0080] The 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 are made of the same material. In detail, the wiring portion 210, the first pad portion 221, and the second pad portion 222 are integrally formed.

[0082] A protective layer 400 is provided on the wiring section 210. The protective layer 400 is not provided on the first pad section 221 and the second pad section 222. Therefore, the first pad section 221 is connected to the display panel 2000. In addition, the second pad section 222 is connected to the circuit board 3000.

[0083] A wiring section 210 is disposed 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 moves. Therefore, at least one of the display panel 2000 and the circuit board 3000 is powered through the wiring section 210.

[0084] The test pattern 300 is connected to the first pad portion 221. The test pattern 300 is removed by the dicing line CL during the process. The flexible circuit board 1100 is tested by the test pattern 300 before cutting the substrate 100 along the dicing line CL. Therefore, defects in the flexible circuit board can be checked in advance.

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

[0086] The wiring section 210 has a spacing P. The spacing P is the sum of the width W of the wiring section and the interval S between wiring sections. The wiring section includes areas where the width W and the interval S are different. Specifically, the wiring section includes areas where the width W is greater than the interval S.

[0087] For example, the spacing S can be 10 μm to 20 μm, 10 μm to 16 μm, or 10 μm to 13 μm. Furthermore, the width W can be 4 to 50 times, 4 to 49.5 times, or 4 to 49 times the spacing S of the wiring section.

[0088] Therefore, the area of ​​the wiring pattern 200 increases. Specifically, the area of ​​the wiring pattern 200 set in the effective area increases.

[0089] The resistance of the wiring pattern 200 is inversely proportional to its area. Therefore, as the width of the wiring portion 210 increases, the resistance of the wiring pattern 200 decreases. The flexible circuit board increases the area of ​​the wiring pattern 200. Therefore, the resistance of the flexible circuit board module 1000 decreases.

[0090] In conventional FPCBs, the width and spacing of the wiring portions are uniform. Therefore, the area of ​​the wiring pattern within the effective region is limited. However, in this embodiment, the width of the wiring portions is greater than the spacing between them. That is, compared to the wiring patterns of conventional FPCBs, the spacing is the same, but the width can be increased.

[0091] Therefore, the resistance of the flexible circuit board is reduced. Consequently, the flexible circuit board can easily supply power to the display panel 2000 and the printed circuit board 3000. Furthermore, signals moving within the display panel 2000 and the printed circuit board 3000 can easily travel through the flexible circuit board.

[0092] The width W and spacing S of the wiring section can vary. Specifically, the wiring section may include multiple regions with different widths and spacings. The wiring section 210 can be divided into a first region 1A, a second region 2A, and a third region 3A according to its position.

[0093] Reference Figure 3 and Figures 5 to 7 The first region 1A is connected to the second region 2A and the third region 3A. The first region 1A bends and extends from the second region 2A. Furthermore, the second region 2A is connected to the first region 1A and the first pad portion 221. Furthermore, the third region 3A is connected to the first region 1A and the second pad portion 222. The third region 3A bends and extends from the first region 1A.

[0094] The first region 1A has a first width W1 and a first interval S1. The second region 2A has a second width W2 and a second interval S2. The third region 3A has a third width W3 and a third interval S3.

[0095] 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 longer than the length of the second region 2A and the third region 3A. Furthermore, the first region 1A is the area where 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 maximum. Therefore, the resistance of the first region 1A is reduced. Therefore, the wiring pattern 200 can be easily powered.

[0096] The second width W2 and the third width W3 are different.

[0097] The second region 2A is the 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 the terminals of the display panel. Therefore, the width of the first pad portion 221 varies according to the size of the terminals of the display panel.

[0098] Furthermore, the third region 3A is the 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 the terminals of the printed circuit board. Therefore, the width of the second pad portion 222 varies according to the size of the terminals of the printed circuit board.

[0099] For example, the second width W2 can be greater than the third width W3.

[0100] 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 length of the second region 2A and the length of the third region 3A. Furthermore, the first region 1A is the region where power is supplied to the display panel 2000 and the printed circuit board 3000. Therefore, the spacing of the first region 1A is minimized. Therefore, the width of the first region 1A is increased while maintaining the same spacing. Therefore, the resistance of the first region 1A is reduced. Therefore, the wiring pattern 200 can be easily powered.

[0101] The second interval S2 and the third interval S3 are different.

[0102] The second region 2A is the region 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 terminals of the display panel. Therefore, the spacing of the first pad portion 221 varies according to the spacing of the terminals of the display panel.

[0103] Furthermore, the third region 3A is the region 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 terminals of the printed circuit board. Therefore, the spacing of the second pad portion 222 varies according to the spacing of the terminals of the printed circuit board.

[0104] For example, the second interval S2 can be greater than the third interval S3.

[0105] The first width W1 is different from the first interval S1. Specifically, the first width W1 is greater than the first interval 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 interval in the wiring section.

[0106] The first region 1A is the longest region in the wiring section. Therefore, the current flowing through the wiring pattern moves the most in the first region 1A. Therefore, the first width W1 is formed to be greater than the first interval S1.

[0107] For example, the first spacing S1 can be 10 μm to 20 μm, 10 μm to 16 μm, or 10 μm to 13 μm. Furthermore, the first width W1 can be 4 to 50 times, 4 to 49.5 times, or 4 to 49 times the first spacing S of the wiring portion.

[0108] Since the first width W1 is greater than the first interval S1, the resistance of the first region 1A is reduced. Therefore, current and signals can easily move through the first region 1A to the display panel 2000 and the printed circuit board 3000.

[0109] The second width W2 is the same as or similar to the second interval S2. For example, the second width W2 is 0.99 to 1.01 times the second interval S2. Furthermore, the third width W3 is the same as or similar to the third interval S3. For example, the third width W3 is 0.99 to 1.01 times the third interval S3.

[0110] The second region 2A is the region connected to the first pad portion 221. In order to prevent short circuits between adjacent first pad portions 221, the second interval S2 has a set size.

[0111] Furthermore, the third region 3A is the region connected to the second pad portion 222. In order to prevent short circuits between adjacent second pad portions 222, the third interval S3 has a set size.

[0112] Therefore, the second width W2 is the same as or similar to the second spacing S2, and the third width W3 is the same as or similar to the third spacing S3. Thus, while sufficiently ensuring the width of the first pad portion 221 and the second pad portion 222, the pad portions can be spaced apart from each other.

[0113] Therefore, the reliability of flexible circuit boards is improved.

[0114] Reference Figure 6 The wiring pattern 200 includes a cut pattern CP. The cut pattern CP is disposed between the first pad portion 221 and the test pattern 300.

[0115] The width W4 of the cutting pattern is smaller than the widths W1, W2, and W3 of the wiring portion. Specifically, the width W4 of the cutting pattern is smaller than the widths W1 of the first region, W2 of the second region, and W3 of the third region. Furthermore, the width W4 of the cutting pattern is smaller than the widths W5 of the first pad portion and W6 of the second pad portion.

[0116] The cutting pattern CP is a pattern cut by the cutting line CL. The width W4 of the cutting pattern is formed to be smaller than that of other areas. Therefore, the flexible circuit board can be easily cut by the cutting pattern CP. In addition, impurities such as debris generated when cutting the flexible circuit board are reduced. Therefore, it is possible to prevent impurities from being adsorbed onto the first pad area. Furthermore, the intensity of the laser required to cut the flexible circuit board is reduced. Therefore, it is possible to prevent damage to the flexible circuit board when cutting it.

[0117] Figure 8 This is a view showing a cutting pattern CP according to another embodiment.

[0118] Reference Figure 8 Wiring pattern 200 includes multiple cut patterns CP. Figure 8 The diagram shows two cutting patterns. However, the embodiment is not limited to this. The cutting patterns may include three or more cutting patterns.

[0119] The 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 disposed between the first pad portion 221 and the test pattern 300.

[0120] The first cutting pattern CP1 and the second cutting pattern CP2 are spaced apart from each other. The width W4' of the first cutting pattern CP1 and the second cutting pattern CP2 is smaller than the width W1 of the first region, the width W2 of the second region, and the width W3 of 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.

[0121] The first cutting pattern CP1 and the second cutting pattern CP2 are patterns cut by cutting lines 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 areas. Therefore, the flexible circuit board can be easily cut by the first cutting pattern CP1 and the second cutting pattern CP2. In addition, the cutting pattern includes multiple cutting patterns. Therefore, even if a crack occurs in any one of the cutting patterns, the first pad portion and the test pattern can be connected by another cutting pattern.

[0122] Wiring patterns can have various layer structures.

[0123] Figures 9 to 12 By cutting Figure 4 Various sectional views were obtained from region A-A'.

[0124] Reference Figure 9 The wiring pattern 200 can 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.

[0125] 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 by electroless plating.

[0126] The second metal layer 520 can be a plating layer. For example, the second metal layer 520 can be a plating layer formed by electroplating using the first metal layer 510 as a seed layer.

[0127] The thickness of the first metal layer 510 is less than the thickness of the second metal layer 520.

[0128] For example, the thickness of the first metal layer 510 can be from 0.7 μm to 2 μm. Furthermore, the thickness of the second metal layer 520 can be from 8 μm to 10 μm.

[0129] The first metal layer 510 and the second metal layer 520 comprise the same metal. For example, the first metal layer 510 and the second metal layer 520 may comprise copper (Cu).

[0130] Furthermore, a bonding layer 530 is provided on the second metal layer 520. The bonding layer 530 may be provided 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.

[0131] The bonding layer 530 may include a metal. Specifically, the bonding layer 530 may include tin (Sn).

[0132] The bonding layer 530 can be formed to have a thickness of 0.3 μm to 0.7 μm. The bonding layer 530 can have a tin content that increases as it extends from the lower surface toward the upper surface.

[0133] That is, the bonding layer 530 contacts the second metal layer 520. Therefore, as it extends from the lower surface toward the upper surface, the tin content increases and the copper content decreases.

[0134] Therefore, on the upper surface of the bonding layer 530, only pure tin may remain within a thickness range of 0.1 μm to 0.3 μm.

[0135] Through the bonding layer 530, the first pad portion 221 and the second pad portion 222 can be easily connected to the terminals of the display panel and the terminals of the printed circuit board. That is, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer in which pure tin remains melts. Therefore, the pad portion, the terminals of the display panel, and the terminals of the circuit board are easily bonded together.

[0136] The thickness of the wiring pattern 200 can be from 8 μm to 12 μm. For example, the thickness of the wiring pattern 200 can be from 9 μm to 11 μm.

[0137] If the thickness of wiring pattern 200 is less than 8 μm, the resistance of wiring pattern 200 may increase. If the thickness of wiring pattern 200 exceeds 12 μm, the folding reliability of the flexible circuit board may decrease.

[0138] The 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.

[0139] The buffer layer 540 can be formed in multiple layers. Specifically, a first buffer layer 541 and a second buffer layer 542 on the first buffer layer 541 can be disposed on the substrate 100. Therefore, the first buffer layer 541 contacts the substrate 100. Furthermore, the second buffer layer 542 contacts the first metal layer 510.

[0140] The first buffer layer 541 may include a material that has good adhesion to the substrate 100. For example, the first buffer layer 541 may include nickel (Ni). Furthermore, the second buffer layer 542 may include a material that has good adhesion to the first metal layer 510. For example, the second buffer layer 542 may include chromium (Cr).

[0141] The buffer layer 540 can have a film thickness in nanometers. For example, the thickness of the buffer layer 540 can be 20 nm or less.

[0142] The adhesion between the substrate 100 and the first metal layer is enhanced by the buffer layer 250. Therefore, peeling of the wiring pattern is prevented.

[0143] Reference Figure 3 and Figure 4 The flexible circuit board 1100 includes a bending region BA. The bending region BA is disposed in a second region 2A. That is, a portion of the second region 2A is bent. In other words, the second region 2A includes a bending region.

[0144] Therefore, stress may be generated in the second region 2A. Furthermore, a portion of the wiring portion 210 may overlap with the bending region. Therefore, if the thickness of the portion of the first wiring portion 210 overlapping the bending region is thick, the bending characteristics may be reduced.

[0145] Furthermore, a portion of the wiring section 210 overlapping with the curved area may crack due to stress. Therefore, the layer structure of the wiring section may differ from the layer structure of the pad pattern.

[0146] Alternatively, the layer structure of a portion of the wiring section that overlaps with the curved area may differ from the layer structure of the other area.

[0147] Reference Figure 10 A flexible circuit board according to another embodiment is described.

[0148] Reference Figure 10 The bonding layer 530 may include multiple bonding layers. For example, the bonding layer 530 may include a first bonding layer 531 and a second bonding layer 532.

[0149] Specifically, the first wiring portion 210, the first pad portion 221, and the second pad portion 222 may include a first bonding layer 531. Furthermore, the first pad portion 221 and the second pad portion 222 may include a second bonding layer 532.

[0150] The first bonding layer 531 and the second bonding layer 532 comprise metal. The first bonding layer 531 and the second bonding layer 532 may comprise the same metal. Specifically, the first bonding layer 531 and the second bonding layer 532 may comprise tin (Sn).

[0151] The thickness of the first bonding layer 531 is different from the thickness of the second bonding layer 532. Specifically, the thickness of the first bonding layer 531 is less than the thickness of the second bonding layer 532.

[0152] For example, the thickness of the first bonding layer 531 can be from 0.02 μm to 0.06 μm. Furthermore, the thickness of the second bonding layer 532 can be from 0.2 μm to 0.6 μm.

[0153] Therefore, the thickness of the bonding layer provided on the wiring portion becomes less than the thickness of the bonding layer provided on the pad portion. That is, the bonding layer provided on the wiring portion is formed to have a thin film thickness.

[0154] The second region 2A overlaps with the wiring section. Furthermore, only the first bonding layer is provided on the wiring section. Therefore, the flexible circuit board can be easily bent in the second region 2A. Moreover, when the flexible circuit board is bent, cracks can be prevented from forming in the bonding layer in the area overlapping with the bending region.

[0155] Reference Figure 11 A flexible circuit board according to another embodiment is described.

[0156] Reference Figure 11 The wiring pattern 200 may include a first bonding layer 531 and a second bonding layer 532.

[0157] A 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, the upper surface of the second metal layer 520, and the side surface of the second metal layer 520. The first bonding layer 531 is disposed in a portion of the second metal layer 520. The second bonding layer 531 is disposed while partially exposing the second metal layer 520. Therefore, an open area OA is formed on the second metal layer 520.

[0158] The open area OA is set in the area corresponding to the second area 2A. The open area OA can be the entire area of ​​the second area 2A. Alternatively, the open area OA can be a portion of the second area 2A.

[0159] A protective layer 400 is provided on the first bonding layer 531. The protective layer 400 is provided while filling the interior of the open area OA. Therefore, the protective layer 400 is provided inside the open area OA.

[0160] 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 surface of the first bonding layer 531. The second bonding layer 532 is not disposed in the area corresponding to the open area OA.

[0161] The wiring section 210 of the second region 2A includes an open region OA. Furthermore, a protective layer 400, comprising a resin material, is disposed inside the open region OA.

[0162] Therefore, the flexible circuit board can be easily bent. Furthermore, when bending the flexible circuit board, the open area prevents cracking in the bonding layer. That is, the second region includes an open area, and the bonding layer is not located in the open area. Therefore, when bending the flexible circuit board, cracking in the bonding layer due to stress can be prevented.

[0163] Reference Figure 12 A flexible circuit board according to another embodiment is described.

[0164] Reference Figure 12 The wiring pattern 200 may include a first bonding layer 531 and a second bonding layer 532.

[0165] A 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 on the upper and side surfaces of the second metal layer 520. The first bonding layer 531 is disposed in a portion of the second metal layer 520. The second bonding layer 531 is disposed while partially exposing the second metal layer 520. Therefore, an open area OA is formed on the second metal layer 520.

[0166] The open area OA is set in the area corresponding to the second area 2A. The open area OA can be the entire area of ​​the second area 2A. Alternatively, the open area OA can be a portion of the second area 2A.

[0167] The 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 contacts the upper surface of the second metal layer 520. Therefore, the first protective layer 410 is disposed inside the open area OA.

[0168] 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 surface of the first bonding layer 531.

[0169] The second protective layer 420 may be 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 with the open area OA.

[0170] The wiring section 210 includes an open area OA. Furthermore, a first protective layer 410 and a second protective layer 420, comprising resin material, are disposed inside the open area OA.

[0171] Therefore, the flexible circuit board can be easily bent. Furthermore, when the flexible circuit board is bent, cracks in the bonding layer can be prevented by the open area. That is, the second region includes an 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 the flexible circuit board is bent, cracks in the bonding layer due to stress can be prevented.

[0172] Figures 13 to 20 When the flexible circuit board has Figures 9 to 12 A cross-sectional view of the layered structure.

[0173] Figure 13and Figure 14 Is when having Figure 9 A cross-sectional view of the layered structure. Figure 15 and Figure 16 Is when having Figure 10 A cross-sectional view of the layered structure. Figure 17 and Figure 18 Is when having Figure 11 A cross-sectional view of the layered structure. Figure 19 and Figure 20 Is when having Figure 12 A cross-sectional view of the layered structure.

[0174] Figure 13 , Figure 15 , Figure 17 and Figure 19 It is a cross-sectional view of the area excluding the second region, and Figure 14 , Figure 16 , Figure 18 and Figure 20 This is a sectional view of the second region.

[0175] Reference Figure 13 and Figure 14 The layer structure of the second region can be the same as that of the regions other than the second region. Specifically, a bonding layer 530 and a protective layer 400 can be provided on the second metal layer 520 in the second region and the regions other than the second region.

[0176] Reference Figure 15 and Figure 16 The layer structure of the second region can be the same as that of the regions other than the second region. Specifically, a first bonding layer 531 and a protective layer 400 can be provided on the second metal layer 520 in the second region and the regions other than the second region. Specifically, the thickness of the first bonding layer 531 is less than the thickness of the second bonding layer 532, and the second bonding layer 532 can be provided only on the first pad portion 221 and the second pad portion 222b.

[0177] Reference Figure 17 and Figure 18 The layer structure of the second region can differ from the layer structure of all other regions. (See reference...) Figure 17 The area other than the second region includes only the area on the second metal layer 262 where the first bonding layer 531 and the protective layer 400 are provided.

[0178] In addition, refer to Figure 18When the open area OA is a part of the second area 2A, the second area includes the area where the protective layer 400 is disposed on the second metal layer 520 and the 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 only includes the area where the protective layer 400 is disposed on the second metal layer 520.

[0179] Specifically, the thickness of the first bonding layer 531 is the same as or similar to the thickness of the second bonding layer 532, and the first bonding layer 531 can be disposed on an area other than the second region. Furthermore, the second bonding layer 532 can be disposed only on the first pad portion 221 and the second pad portion 222.

[0180] Reference Figure 19 and Figure 20 The layer structure of the second region can differ from the layer structure of all other regions. (See reference...) Figure 19 The area other than the second region includes only the area on the second metal layer 520 where the first bonding layer 531 and the second protective layer 420 are provided.

[0181] In addition, refer to Figure 20 When the open area OA is a part of the second area 2A, the second area includes the area where the first protective layer 410 and the second protective layer 420 are disposed on the second metal layer 520, and the 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 only includes the area where the first protective layer 410 and the second protective layer 420 are disposed on the second metal layer 520. Specifically, the thickness of the first bonding layer 531 is the same as or similar to the thickness of the second bonding layer 532, and the first bonding layer 531 can be disposed on areas other than the second area. Furthermore, 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 area and areas other than the second area.

[0182] Because flexible circuit board modules are flexible, they can be used in a variety of electronic devices.

[0183] For example, refer to Figure 21 Flexible circuit board modules can be applied to flexible touch devices that can be bent. Therefore, users can bend or fold the touch device by hand.

[0184] Reference Figure 22 Flexible circuit board modules can be applied to wearable touch devices, including those with curved displays.

[0185] Reference Figure 23 and Figure 24 Flexible circuit board modules can be applied to various electronic devices with display components, such as TVs, monitors, and laptops. They can also be used in electronic devices with curved display components.

[0186] The features, structures, and effects described in the above embodiments are included in at least one embodiment, but are not limited to one embodiment. Furthermore, those skilled in the art to which the embodiments pertain can combine or modify the features, structures, and effects shown in each of the embodiments even with respect to other embodiments. Therefore, it should be understood that content related to such combinations and modifications is included within the scope of the embodiments.

[0187] The description focuses on the embodiments, but is merely illustrative and does not limit the scope of the embodiments. Those skilled in the art will understand that various modifications and applications not shown above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically represented in the embodiments can be modified and implemented. Furthermore, it should be understood that differences associated with these changes and applications are included within the scope of the embodiments defined in the appended claims.

Claims

1. A flexible circuit board, comprising: A substrate, the substrate including a first surface and a second surface opposite to the first surface; Multiple wiring patterns are disposed on the first surface; as well as A protective layer is disposed on the plurality of wiring patterns. The plurality of wiring patterns include: The first pad portion is connected to the display panel; The second solder pad portion is connected to the circuit board; and A wiring section, the wiring section connecting the first pad section and the second pad section, and The wiring portion includes a region whose width is greater than the interval between the wiring portions.

2. The flexible circuit board according to claim 1, wherein, The width of the wiring section is 4 to 50 times the spacing.

3. The flexible circuit board according to claim 1, wherein, The wiring section includes multiple areas with different widths.

4. The flexible circuit board according to claim 3, wherein, The 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 interval. The second region has a second width and a second interval. The third region has a third width and a third interval, and Wherein, the first width is greater than the second width and the third width.

5. The flexible circuit board according to claim 4, wherein, The first region bends and extends from the second region. The third region bends and extends from the first region, and The length of the first region is longer than the length of the second region and the length of the third region.

6. The flexible circuit board according to claim 5, wherein, The first interval is smaller than the second interval and the third interval.

7. The flexible circuit board according to claim 5, wherein, The first width is greater than the first interval. Wherein, the second width is 0.99 to 1.01 times the second interval, and The third width is 0.99 to 1.01 times the third interval.

8. The flexible circuit board according to claim 1, further comprising: Test pattern, the test pattern being connected to the first pad portion, Wherein, at least one cutting pattern is provided between the first pad portion and the test pattern, and The width of the cutting pattern is smaller than the width of the wiring portion.

9. The flexible circuit board according to claim 8, wherein, The width of the cutting pattern is less than the width of at least one of the first pad portion and the second pad portion.

10. The flexible circuit board according to claim 8, wherein, The cutting pattern comprises multiple cutting patterns spaced apart from each other.

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