Flexible circuit board, COF module and electronic device comprising COF module

Abstract

A flexible circuit board according to an embodiment includes: a substrate including a first surface and a second surface opposite to the first surface; a first circuit pattern disposed on the first surface; a second circuit pattern disposed on the first surface and the second surface; and a third circuit pattern disposed on the first surface and the second surface, in which the second circuit pattern includes a first conductive portion and a second wiring portion, the third circuit pattern includes a second conductive portion and a third wiring portion, each of the first conductive portion and the second conductive portion includes a conductive portion zone and a conductive via formed in the conductive portion zone, at least one of the first conductive portion and the second conductive portion defines a first pitch between conductive portion zones, a second pitch between the conductive portion zones and the second wiring portion or the third wiring portion adjacent to the conductive portion zones, and a third pitch between side surfaces of the conductive portion zones and the conductive hole. And at least one of the first pitch, the second pitch, and the third pitch is larger than a width of the wiring portion.

Description

Technical Field

[0001] An embodiment relates to a flexible printed circuit board, a COF module, and an electronic device including the COF module. Background Art

[0002] Recently, various electronic products have become thinner, smaller, and lighter. Accordingly, various studies are being conducted to mount semiconductor chips at high density in a narrow area of an electronic product.

[0003] A COF (Chip On Film) includes a flexible substrate. Accordingly, a COF can be applied to a flexible display. For example, a COF can be applied to various wearable electronic devices. In addition, a COF method can implement a fine pitch, and thus, a high-resolution display can be realized due to an increase in the number of pixels.

[0004] A COF is a method of mounting a semiconductor chip in the form of a thin film on a flexible printed circuit board. For example, the semiconductor chip may be an integrated circuit (IC) chip or a large scale integrated circuit (LSI) chip.

[0005] The chip can be connected to an external circuit board and a display panel through a circuit pattern. For example, pad portions are respectively provided at one end and the other end of the circuit pattern, and one pad portion is electrically connected to a terminal of the chip. In addition, the other pad portion can be connected to terminals of the circuit board and the display panel. Accordingly, the chip, the circuit board, and the display panel are electrically connected through the COF. Accordingly, signals can be transmitted to the display panel through the circuit pattern.

[0006] The flexible printed circuit board includes a plurality of circuit patterns. The circuit patterns connect the chip, the circuit board, and the display panel. Signals can be transmitted to the chip, the circuit board, and the display panel through the circuit patterns.

[0007] The circuit patterns may be provided on one surface or both surfaces of the substrate. When the circuit patterns are provided on both surfaces of the substrate, the circuit patterns on the two surfaces are connected through a via.

[0008] If the alignment of the via is not aligned, the circuit patterns on the two surfaces of the substrate may be short-circuited. Accordingly, the reliability of the flexible printed circuit board may be reduced.

[0009] Accordingly, there is a need for a flexible printed circuit board, a COF module, and an electronic device including the COF module having a novel structure that can solve the above problems. Summary of the Invention

[0010] Technical Problem

[0011] Embodiments of the present disclosure provide a flexible printed circuit board, a COF module, and an electronic device including the COF module having improved reliability.

[0012] Technical solution

[0013] The flexible printed circuit board according to the embodiment includes: a substrate including a first surface and a second surface opposite to the first surface; a first circuit pattern disposed on the first surface; a second circuit pattern disposed on the first surface and the second surface; and a third circuit pattern disposed on the first surface and the second surface, wherein the second circuit pattern includes a first conduction portion and a second wiring portion, wherein the third circuit pattern includes a second conduction portion and a third wiring portion, wherein the first conduction portion and the second conduction portion include via lands and vias formed in the via lands, wherein at least one of the first conduction portion and the second conduction portion defines a first pitch between the via lands, a second pitch between the via land and the second wiring portion or the third wiring portion adjacent to the via land, and a third pitch between the side surface of the via land and the via, and wherein at least one of the first pitch, the second pitch, and the third pitch is greater than the width of the wiring portion.

[0014] Advantageous effects

[0015] The flexible printed circuit board according to the embodiment includes conduction portions. The circuit patterns on the first surface and the second surface are connected through the conduction portions. The conduction portions are respectively disposed on the first surface and the second surface. The conduction portion includes a plurality of via lands and vias inside the via lands.

[0016] The via lands are spaced apart by a set range of pitches. In addition, the via lands are spaced apart from the wiring portions of the circuit pattern by a set range of pitches. In addition, the via lands are spaced apart from the vias by a set range of pitches.

[0017] Therefore, the vias inside the via lands are not misaligned. Therefore, the alignment of the conduction portions on the first surface and the second surface is not misaligned.

[0018] Therefore, the electrical connection characteristics of the flexible printed circuit board are improved.

[0019] The via land includes a plurality of corner portions. At least one corner portion includes a curved surface. The pitch of the via land on which the curved surface is formed is wider than other pitches. In addition, the pitch between the wiring portion and the via land on which the curved surface is formed is formed wider than other pitches.

[0020] Therefore, when patterning the via lands and the wiring portions, connection between adjacent via lands is prevented. In addition, connection between adjacent via lands and wiring portions is prevented.

[0021] Therefore, the reliability of the flexible printed circuit board is improved. Description of the drawings

[0022] Figure 1 It is a top view of a flexible printed circuit board according to an embodiment.

[0023] Figure 2 It is a bottom view of a flexible printed circuit board according to an embodiment.

[0024] Figure 3 It is Figure 1 an enlarged view of region A of

[0025] Figure 4 It is Figure 1 an enlarged view of region B of

[0026] Figure 5 It is Figure 2 an enlarged view of region C of

[0027] Figure 6 It is Figure 2 an enlarged view of region D of

[0028] Figure 7 It is Figure 1 an enlarged view of region E of

[0029] Figure 8 It is Figure 1 an enlarged view of region F of

[0030] Figure 9 It is Figure 1 an enlarged view of region G of

[0031] Figure 10 It is a diagram for explaining a COF module according to an embodiment.

[0032] Figure 11 and Figure 12 are cross-sectional views taken along Figure 3 section line A - A' of

[0033] Figure 13 It is a top view of a flexible printed circuit board according to another embodiment.

[0034] Figure 14 It is a bottom view of a flexible printed circuit board according to another embodiment.

[0035] Figure 15 It is Figure 13 an enlarged view of region A of

[0036] Figure 16 It is Figure 14 an enlarged view of region B of

[0037] Figure 17 It is Figure 13 an enlarged view of region C of

[0038] Figure 18 is Figure 14 an enlarged view of region D of

[0039] Figure 19 is a cross-sectional view taken along Figure 17 section line B-B’ of

[0040] Figure 20 is Figure 13 another enlarged view of region C of

[0041] Figure 21 is Figure 13 another enlarged view of region C of

[0042] Figure 22 is Figure 13 another enlarged view of region C of

[0043] Figure 23 is Figure 13 another enlarged view of region C of

[0044] Figure 24 is a diagram for explaining the connection of the COF module according to an embodiment to other components.

[0045] Figures 25 to 27 is a diagram of an electronic device including a flexible printed circuit board according to an embodiment. DETAILED DESCRIPTION

[0046] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the spirit and scope of the present disclosure are not limited to a part of the described embodiments, and can be implemented in various other forms, and one or more of the elements of the embodiments can be selectively combined and rearranged within the spirit and scope of the present disclosure.

[0047] In addition, unless otherwise clearly defined and described, the terms (including technical terms and scientific terms) used in the embodiments of the present disclosure can be interpreted as having the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure pertains, and for example, those terms defined in a commonly used dictionary can be interpreted as having a meaning consistent with their meaning in the context of the relevant field. In addition, the terms used in the embodiments of the present disclosure are used to describe the embodiments and are not intended to limit the present disclosure.

[0048] In this specification, unless specifically stated in the text, 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.

[0049] In addition, when describing the elements of the embodiments of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish one element from other elements, and these terms are not limited to the nature, order, or sequence of the elements.

[0050] In addition, when an element is described as "connected", "coupled", or "contacted" with another element, it may include not only the case where the element is directly "connected", "coupled", or "contacted" with other elements, but also the case where the element is "connected", "coupled", or "contacted" with other elements through another element between the element and other elements.

[0051] In addition, when described as being formed or disposed "on (above)" or "under (below)" each element, "on (above)" or "under (below)" may include not only the case where two elements are directly connected to each other, but also the case where one or more other elements are formed or disposed between the two elements.

[0052] In addition, when expressed as "on (above)" or "under (below)", it may include not only the upward direction based on one element, but also the downward direction based on one element.

[0053] In addition, in the following description, the first direction 1D may be defined as the width direction of the flexible printed circuit board, and the second direction 2D may be defined as the length direction of the flexible printed circuit board.

[0054] Hereinafter, a flexible printed circuit board, a COF module, and an electronic device including the COF module according to an embodiment will be described with reference to the drawings.

[0055] Referring to Figures 1 to 6 , the flexible printed circuit board 1000 includes a substrate 100, a circuit pattern, and a protective layer.

[0056] The 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 are disposed on the first surface 1S and the second surface 2S.

[0057] The substrate 100 includes a cutting line CL. The flexible printed circuit board 1000 is cut along the cutting line CL. For example, after the circuit pattern, the protective layer, and the chip are disposed on the substrate 100, the substrate 100 may be cut along the cutting line CL. Thus, the flexible printed circuit board 1000 is manufactured as the COF module 2000.

[0058] The substrate 100 may include an active region AA and a passive region UA. The active region AA and the passive region UA are separated by the cutting line CL. The active region AA is the inner region of the cutting line CL. The passive region UA is the outer region of the cutting line CL.

[0059] The circuit pattern, the protective layer, and the chip are disposed on the active region AA. In addition, the dummy pattern DP and the sprocket hole SH are disposed on the passive region UA. The strength of the substrate 100 is increased by the dummy pattern. Thereby, the flexible circuit board 1000 is prevented from being bent. The flexible circuit board 1000 is wound or unwound in a roll-to-roll manner through the sprocket hole SH.

[0060] The substrate 100 includes a chip mounting region CHA. The chip mounting region CHA is disposed on the first surface 1S. The chip mounting region CHA is disposed inside the active region AA. The chip is disposed on the chip mounting region CHA. In addition, the pad portion of the circuit pattern is disposed inside the chip mounting region CHA. In addition, the protective layer is not disposed on the chip mounting region CHA.

[0061] The substrate 100 may include a flexible material. For example, the substrate 100 may include polyimide (PI). However, the embodiments are not limited thereto. The substrate 100 may include a polymer material including polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Therefore, the flexible circuit board can be used in various electronic devices including a curved display device.

[0062] The thickness of the substrate 100 may be from 20 μm to 100 μm. For example, the thickness of the substrate 100 may be from 25 μm to 50 μm. For example, the thickness of the substrate 100 may be from 30 μm to 40 μm. If the thickness of the substrate 100 exceeds 100 μm, the thickness of the flexible circuit board may increase. Therefore, the flexible characteristics of the flexible circuit board are reduced. In addition, if the thickness of the substrate 100 is less than 20 μm, the strength of the substrate is reduced. Therefore, when a chip is mounted on the flexible circuit board, the substrate 100 may be damaged due to the heat and pressure transferred to the substrate 100.

[0063] The circuit pattern and the protective layer are disposed on the substrate 100. For example, the circuit pattern and the protective layer may be disposed on the active region AA and the passive region UA.

[0064] The circuit pattern may include a first circuit pattern 210, a second circuit pattern 220, a third circuit pattern 230, and a fourth circuit pattern 240. In addition, the protective layer may include a first protective layer 310 and a second protective layer 320.

[0065] Refer to Figure 1 and Figure 3, a first circuit pattern 210 is provided on a first surface 1S. The first circuit pattern 210 includes a first wiring portion 211, a first pad portion 212a, and a second pad portion 212b. The first wiring portion 211, the first pad portion 212a, and the second pad portion 212b may include the same material. The first wiring portion 211, the first pad portion 212a, and the second pad portion 212b may be integrally formed.

[0066] The first pad portion 212a is provided inside the chip mounting area CHA. Accordingly, the first pad portion 212a is connected to the terminals of the chip. Accordingly, the first circuit pattern 210 is connected to the chip.

[0067] The second pad portion 212b is provided outside the chip mounting area CHA. The second pad portion 212b is connected to the terminals of the circuit board. Accordingly, the first circuit pattern 210 is connected to the circuit board.

[0068] The second pad portion 212b may include a first test pad portion. The first circuit pattern 210 is tested before connecting the circuit board and the second pad portion 212b. For example, the first test pad portion can be used to check whether the first circuit pattern is open or short-circuited.

[0069] The first wiring portion 211 is provided between the first pad portion 212a and the second pad portion 212b. The first wiring portion 211 connects the first pad portion 212a and the second pad portion 212b. Accordingly, the chip is connected to the circuit board. Accordingly, the signal generated from the chip is transmitted to the circuit board.

[0070] A first protective layer 310 is provided on the first circuit pattern 210. The first protective layer 310 is provided on the area other than the first pad portion 212a and the second pad portion 212b.

[0071] Refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 , a second circuit pattern 220 is provided on the first surface 1S and the second surface 2S. The second circuit pattern 220 includes second wiring portions 221a and 221b, a third pad portion 222a, a fourth pad portion 222b, and a first conduction portion V1. The second wiring portions 221a and 221b, the third pad portion 222a, and the fourth pad portion 222b may include the same material. Additionally, the second wiring portions 221a and 221b, the third pad portion 222a, and the fourth pad portion 222b may be integrally formed.

[0072] The third pad portion 222a is provided on the first surface 1S. The third pad portion 222a is provided inside the chip mounting area CHA. Accordingly, the third pad portion 222a is connected to the terminals of the chip. Accordingly, the second circuit pattern 220 is connected to the chip.

[0073] The fourth pad portion 222b is provided on the second surface 2S. The fourth pad portion 222b is connected to the terminal of the display panel. Accordingly, the second circuit pattern 220 is connected to the display panel.

[0074] The second wiring portion includes a 2-1 wiring portion 221a and a 2-2 wiring portion 221b. The 2-1 wiring portion 221a is provided on the first surface 1S. The 2-2 wiring portion 221b is provided on the second surface 2S. The second wiring portion connects the third pad portion 222a and the fourth pad portion 222b. The 2-1 wiring portion 221a is connected to the third pad portion 222a. In addition, the 2-2 wiring portion 221b is connected to the fourth pad portion 222b.

[0075] Accordingly, the chip is connected to the display panel. Accordingly, the signal generated from the chip is transmitted to the display panel.

[0076] The first protective layer 310 and the second protective layer 320 are provided on the second circuit pattern 220. The first protective layer 310 is provided on the second circuit pattern 220 on the first surface 1S. The second protective layer 320 is provided on the second circuit pattern 220 on the second surface 2S. The first protective layer 310 and the second protective layer 320 are provided on the regions other than the third pad portion 222a and the fourth pad portion 222b.

[0077] The 2-1 wiring portion 221a is connected to the 2-2 wiring portion 221b. The 2-1 wiring portion 221a and the 2-2 wiring portion 221b are connected by a first conduction portion V1. The first conduction portion V1 penetrates the substrate 100. The first conduction portion V1 is provided on the first surface 1S and the second surface 2S. The first conduction portion V1 on the first surface 1S and the first conduction portion V1 on the second surface 2S are provided at corresponding positions.

[0078] The first conduction portion V1 includes a first conduction portion zone VL1 and a first via hole VH1. The first via hole VH1 is formed inside the first conduction portion zone VL1. A conductive material is provided in the first via hole VH1. Accordingly, the 2-1 wiring portion 221a is electrically connected to the 2-2 wiring portion 221b.

[0079] The second circuit pattern 220 may include a second test pad portion TP2. The second test pad portion TP2 may be provided on the second surface 2S. The second test pad portion TP2 may be provided on the passive region UA. The second protective layer 320 is not provided on the second test pad portion TP2. The second test pad portion TP2 may be connected to the 2-2 wiring portion 221b. The second test pad portion TP2 may be integrally formed with the 2-2 wiring portion 221b.

[0080] The second circuit pattern 220 can be tested before connecting the display panel to the fourth pad portion 222b. For example, the second test pad portion TP2 can be used to check whether the second circuit pattern is open or short-circuited.

[0081] Referring to Figure 1 , Figure 2 , Figure 3 and Figure 6 , the third circuit pattern 230 is disposed on the first surface 1S and the second surface 2S. The third circuit pattern 230 includes a third wiring portion 231, a fifth pad portion 232a, a sixth pad portion 232b, and a second conduction portion V2. The third wiring portion 231, the fifth pad portion 232a, and the sixth pad portion 232b may include the same material. The third wiring portion 231, the fifth pad portion 232a, and the sixth pad portion 232b may be integrally formed.

[0082] The fifth pad portion 232a is disposed on the first surface 1S. The fifth pad portion 232a is disposed inside the chip mounting area CHA. Therefore, the fifth pad portion 232a is connected to the terminals of the chip. Therefore, the third circuit pattern 230 is connected to the chip.

[0083] The sixth pad portion 232b is disposed on the second surface 2S. The sixth pad portion 232b is connected to the terminals of the display panel. Therefore, the third circuit pattern 230 is connected to the display panel.

[0084] The third wiring portion 231 connects the fifth pad portion 232a and the sixth pad portion 232b. Therefore, the chip is connected to the display panel. Therefore, the signal generated from the chip is transmitted to the display panel.

[0085] The second protective layer 320 is disposed on the third circuit pattern 230. The second protective layer 320 is disposed on the third circuit pattern 230 on the second surface 2S. The second protective layer 320 is disposed on the area except the fifth pad portion 232a and the sixth pad portion 232b.

[0086] The fifth pad portion 232a is connected to the third wiring portion 231. The fifth pad portion 232a and the third wiring portion 231 are connected through the second conduction portion V2. The second conduction portion V2 is disposed on the first surface 1S and the second surface 2S. The second conduction portion penetrates the substrate 100. The second conduction portion V2 on the first surface 1S and the second conduction portion V2 on the second surface 2S are disposed at corresponding positions.

[0087] The second conduction portion V2 includes a second conduction portion zone VL2 and a second via hole VH2. The second via hole VH2 is formed inside the second conduction portion zone VL2. A conductive material is disposed in the second via hole VH2. Therefore, the fifth pad portion 232a is electrically connected to the third wiring portion 231.

[0088] The third circuit pattern 230 may include a third test pad portion TP3. The third test pad portion TP3 may be disposed on the second surface 2S. The third test pad portion TP3 may be disposed on the passive region UA. The second protective layer 320 is not disposed on the third test pad portion TP3. The third test pad portion TP3 may be connected to the third wiring portion 231. The third test pad portion TP3 may be integrally formed with the third wiring portion 231.

[0089] Before connecting the display panel to the sixth pad portion 232b, the third circuit pattern 230 may be tested. For example, the third test pad portion TP3 may be used to check whether the third circuit pattern is open or short-circuited.

[0090] Referring to Figure 1 、 Figure 7 and Figure 8 As shown in FIGS.

[0091] The seventh pad portion 242a is disposed on the first surface 1S. The seventh pad portion 242a is disposed adjacent to the first pad portion 212a. The seventh pad portion 242a is connected to a terminal of the circuit board. Accordingly, the fourth circuit pattern 220 is connected to the circuit board.

[0092] The eighth pad portion 242b is disposed on the second surface 2S. The eighth pad portion 242b is connected to a terminal of the display panel. Accordingly, the fourth circuit pattern 240 is connected to the display panel.

[0093] The fourth wiring portion includes a 4-1 wiring portion 241a and a 4-2 wiring portion 241b. The 4-1 wiring portion 241a is disposed on the first surface 1S. The 4-2 wiring portion 241b is disposed on the second surface 2S. The fourth wiring portion connects the seventh pad portion 242a and the eighth pad portion 242b. The 4-1 wiring portion 241a is connected to the seventh pad portion 242a. The 4-2 wiring portion 241b is connected to the eighth pad portion 242b.

[0094] Accordingly, the circuit board is connected to the display panel. Accordingly, the circuit board and the display panel can exchange signals with each other.

[0095] The first protective layer 310 and the second protective layer 320 are disposed on the fourth circuit pattern 240. The first protective layer 310 is disposed on the fourth circuit pattern 240 on the first surface 1S. The second protective layer 320 is disposed on the fourth circuit pattern 240 on the second surface 2S. The first protective layer 310 and the second protective layer 320 are disposed on an area other than the seventh pad portion 242a and the eighth pad portion 242b.

[0096] The 4-1 wiring portion 241a is connected to the 4-2 wiring portion 241b. The 4-1 wiring portion 241a and the 4-2 wiring portion 241b are connected through the third conduction portion V3. The third conduction portion V3 is disposed on the first surface 1S and the second surface 2S. The third conduction portion V3 penetrates the substrate 100. The third conduction portion V3 on the first surface 1S and the third conduction portion V3 on the second surface 2S are disposed at corresponding positions.

[0097] The third conduction portion V3 includes a third conduction portion zone VL3 and a third via hole VH3. The third via hole VH3 is formed inside the third conduction portion zone VL3. A conductive material is disposed in the third via hole VH3. Accordingly, the 4-1 wiring portion 241a is electrically connected to the 4-2 wiring portion 241b.

[0098] The circuit patterns 210, 220, 230, and 240 may include a metal material having excellent conductivity. Specifically, the circuit patterns 210, 220, 230, and 240 may include copper (Cu). However, the embodiments are not limited thereto. The circuit patterns 210, 220, 230, and 240 may include at least one metal among copper (Cu), aluminum (A1), chromium (Cr), nickel (Ni), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and their alloys.

[0099] In addition, the first protective layer 310 and the second protective layer 320 may include solder paste. The solder paste may include a thermosetting resin, a thermoplastic resin, a filler, a curing agent, or a curing accelerator.

[0100] As described above, the flexible printed circuit board 1000 includes a plurality of conduction portions. The flexible printed circuit board 1000 includes a first conduction portion V1, a second conduction portion V2, and a third conduction portion V3.

[0101] The conduction portion zone and the via hole may have set dimensions. The conduction portion zone may have a set distance. The conduction portion zone and the wiring portion may have a set distance. Accordingly, the flexible printed circuit board may have improved reliability, alignment characteristics, and process efficiency.

[0102] Refer to Figure 9 and Figure 10 , the conduction portions and the wiring portions of the flexible printed circuit board according to the embodiments will be described. In Figure 9For convenience of explanation, the description will be based on the first conduction portion. The following description is equally applicable to the second conduction portion and the third conduction portion.

[0103] Referring to Figure 9 , the first conduction portion zone VL1 has a first length L1 and a second length L2. The first length L1 is the length in the first direction 1D. The second length L2 is the length in the second direction 2D. The first length L1 and the second length L2 may be the same or similar.

[0104] The first length L1 and the second length L2 have set dimensions. For example, the first length L1 and the second length L2 may be 60 μm to 80 μm, 65 μm to 80 μm, or 67 μm to 75 μm.

[0105] If the first length L1 and the second length L2 are less than 60 μm, the area of the first conduction portion zone VL1 decreases. Therefore, it is difficult to form the first conduction hole VL1 inside the first conduction portion zone VL1. Therefore, the position or size of the first conduction hole VH1 may change. Therefore, the alignment characteristics of the first conduction hole VL1 deteriorate.

[0106] If the first length L1 and the second length L2 exceed 80 μm, the area of the first conduction portion zone VL1 increases. Therefore, the border area of the display panel connected to the COF module 2000 may increase.

[0107] Referring to Figure 10 , the COF module 2000 includes a first region 1A and a second region 2A. The first region 1A is a region where the conduction portions V1, V2, and V3 are not provided. The second region 2A is a region where the first conduction portion V1 and the third conduction portion V3 are provided.

[0108] The COF module 2000 and the display panel 4000 are connected in the second region 2A. The COF module 2000 is bent in the first region 1A. That is, the COF module 2000 is bent in the region where the conduction portions V1, V2, and V3 are not provided. Therefore, the second region 2A becomes the border area of the display panel 4000. Therefore, when the area of the first conduction portion zone VL1 increases, the border area of the display panel 4000 may increase. Therefore, the active area of the display panel 4000 may decrease.

[0109] The first conduction hole VH1 has a first width W1. The first width W1 has a set dimension. For example, the first width W1 may be 20 μm to 30 μm, 22 μm to 28 μm, or 23 μm to 27 μm.

[0110] If the first width W1 is less than 20 μm, the alignment characteristics of the first via hole VH1 deteriorate. As a result, the connection characteristics of the first wiring portion 221 on the first surface 1S and the second surface 2S are reduced.

[0111] If the first width W1 exceeds 30 μm, it is difficult to form the first via hole VL1 inside the first conduction portion area VL1. Therefore, the position or size of the first via hole VH1 may change. As a result, the alignment characteristics of the first via hole VL1 deteriorate.

[0112] The plurality of first conduction portion areas VL1 have a first pitch G1. The first conduction portion area VL1 and the first wiring portion 221 have a second pitch G2. The first via hole VH1 and the first conduction portion area VL1 have a third pitch G3.

[0113] The first pitch G1, the second pitch G2, and the third pitch G3 may be different from the second width W2 of the first wiring portion 221. For example, the first pitch G1, the second pitch G2, and the third pitch G3 may be greater than the second width W2.

[0114] For example, the first pitch G1 may be 1.1 times, 1.5 times, 2 times, 2.5 times, or 3 times or more the second width W2. For example, the first pitch G1 may be greater than 1 times the second width W2 and less than or equal to 5 times the second width W2. Since the first pitch G1 is set within the above range, a sufficient distance between the first conduction portion areas VL1 can be ensured. Therefore, adjacent first conduction portion areas VL1 are prevented from being connected during the process.

[0115] The second pitch G2 may be 1.1 times, 1.5 times, 2 times or more the second width W2. For example, the second pitch G2 may be greater than 1 times the second width W2 and less than or equal to 3 times the second width W2. Since the second pitch G2 is set within the above range, a sufficient distance between the first wiring portions 221 can be ensured. Therefore, adjacent first wiring portions 221 are prevented from being connected during the process.

[0116] The third pitch G3 may be 1.1 times, 1.5 times, 2 times, 2.5 times, or 3 times or more the second width W2. For example, the third pitch G3 may be greater than 1 times and less than or equal to 5 times the second width W2. Since the third pitch G3 is set within the above range, the first via hole VH1 can be formed with a sufficient area. Thereby, the alignment characteristics of the first via hole VH1 are improved. In addition, the first via hole VH1 can be easily formed.

[0117] The first pitch G1 and the second pitch G2 may be different. Specifically, the first pitch G1 may be greater than the second pitch G2. For example, the first pitch G1 may be more than 1 times greater than the second pitch G2. Specifically, the first pitch G1 may be 1.1 times, 1.5 times, 2 times, or more than 3 times that of the second pitch G2. For example, the first pitch G1 may be from 1.1 times to 5 times that of the second pitch G2.

[0118] For example, the first pitch G1 may be 12 μm or more. Specifically, the first pitch G1 may be from 12 μm to 30 μm, from 13 μm to 25 μm, or from 14 μm to 20 μm.

[0119] In addition, the second pitch G2 may be less than 12 μm. Specifically, the second pitch G2 may be from 3 μm to 11 μm or from 5 μm to 10 μm.

[0120] Since the first pitch G1 is set within the above range, the process efficiency of the first conduction part zone VL1 can be improved. The first conduction part zone VL1 is provided with an area larger than that of the first wiring part 221.

[0121] For example, when forming the first conduction part zone VL1, the first conduction part zone VL1 is plated with an area larger than that of the first wiring part 221. Therefore, during the plating process, the DFR (Dry film resist) pattern between the first conduction part zones VL1 may be damaged. Therefore, the process efficiency of the first conduction part zone VL1 may be reduced.

[0122] Therefore, the first pitch G1 is formed into a sufficient size. Therefore, the process efficiency of the flexible circuit board 1000 is improved.

[0123] The first conduction part zone VL1 includes a plurality of corner parts. The corner parts may have a curved surface. The first conduction part zone VL1 includes at least one curved surface having a first radius of curvature R1. For example, the corner part may include one or two corner parts connected to the first wiring part 221. In addition, the corner part may include two or three corner parts not connected to the first wiring part 221. At least one corner part not connected to the first wiring part 221 includes at least one curved surface. In addition, the curved surface has a first radius of curvature R1.

[0124] Thereby, a region with different pitches between the first conduction part zones VL1 is formed. In addition, a region with different pitches between the first conduction part zone VL1 and the first wiring part 221 is formed. That is, the first pitch G1 increases at the corner parts of the first conduction part zone VL1. In addition, the second pitch G2 increases at the corner parts of the first conduction part zone VL1.

[0125] Specifically, the first conductive portion zone VL1 adjacent to the corner portion has a fourth pitch G4. Additionally, the first conductive portion zone VL1 adjacent to the corner portion and the first wiring portion have a fourth pitch G4. The fourth pitch G4 can be greater than the first pitch G1 and the second pitch G2.

[0126] Therefore, the corner portion can be easily patterned. That is, the first pitch G1 and the second pitch G2 become larger at corner portions with different patterning directions. Thus, adjacent first conductive portion zones VL1 are prevented from connecting during the process. Additionally, the first conductive portion zone VL1 is prevented from connecting to the first wiring portion 221.

[0127] The first via hole VH1 is formed as a circle having a second curvature radius R2.

[0128] The first curvature radius R1 and the second curvature radius R2 can be different. Specifically, the first curvature radius R1 can be greater than the second curvature radius R2. That is, the curvature of the corner portion is less than the curvature of the first via hole VH1. For example, the first curvature radius R1 can be 30 μm or less. Specifically, the first curvature radius R1 can be 1 μm to 30 μm, 5 μm to 25 μm, or 10 μm to 20 μm.

[0129] Additionally, the first via hole VH1 is spaced apart from the corner portion by a fifth pitch G5.

[0130] The fourth pitch G4 and the fifth pitch G5 can be different. Specifically, the fifth pitch G5 can be greater than the fourth pitch G4.

[0131] Furthermore, the third pitch G3 and the fifth pitch G5 can be different. Specifically, the fifth pitch G5 can be greater than the third pitch G3.

[0132] Therefore, since the process of aligning the conductive portions becomes easy, the reliability of the flexible circuit board is improved.

[0133] Figure 11 and Figure 12 are diagrams for explaining the layer structure of the circuit pattern. Figure 9 and Figure 10 The first circuit pattern is illustrated as an example.

[0134] Referring to Figure 11 , the first circuit pattern is formed in multiple layers. Specifically, the first wiring portion 211, the first pad portion 212a, and the second pad portion 212b include a buffer layer 205, a metal layer 201, and a bonding layer 203.

[0135] The buffer layer 205 may include multiple layers. Specifically, the buffer layer 205 includes a first buffer layer 205a and a second buffer layer 205b. The first buffer layer 205a is disposed on the substrate 100. The second buffer layer 205b is disposed on the first buffer layer 205a.

[0136] The first buffer layer 205a contains a material having good adhesion to the substrate 100. For example, the first buffer layer 205a may contain nickel (Ni). Additionally, the second buffer layer 205b contains a material having good adhesion to the first circuit pattern. For example, the second buffer layer 205b may contain chromium (Cr).

[0137] The buffer layer 205 may have a thin film thickness in nanometer units. For example, the thickness of the buffer layer 205 may be 20 nm or less.

[0138] Through the buffer layer 205, the adhesion between the substrate 100 and the first circuit pattern is improved.

[0139] The metal layer 201 is disposed on the buffer layer 205. Specifically, the metal layer 201 is disposed on the second buffer layer 205b. The metal layer 201 contains a metal material. For example, the metal layer 201 may contain copper (Cu).

[0140] The buffer layer can be used as a seed layer to form the metal layer 201 by electroplating. That is, the metal layer 201 can be a plating layer.

[0141] The thickness of the metal layer 201 can be 10 μm to 30 μm.

[0142] The bonding layer 203 is disposed on the metal layer 201.

[0143] The bonding layer 203 is disposed on the side surface and the upper surface of the metal layer 201. For example, the bonding layer 203 can be disposed to surround the metal layer 201.

[0144] The bonding layer 203 contains a metal. For example, the bonding layer 203 may contain tin (Sn).

[0145] The thickness of the bonding layer 203 can be 0.3 μm to 0.7 μm. The tin content can increase as it extends from the lower surface to the upper surface of the bonding layer 203.

[0146] That is, the bonding layer 203 is in contact with the metal layer 201. Therefore, the tin content increases as it extends from the lower surface to the upper surface of the bonding layer 203. In addition, the copper content decreases as it extends from the lower surface to the upper surface of the bonding layer 203.

[0147] Therefore, pure tin can remain in a thickness range of 0.1 μm to 0.3 μm from the upper surface of the bonding layer 203.

[0148] The pad portion can be easily bonded to the terminals of the chip, circuit board, and display panel through the bonding layer 203. For example, when heat and pressure are applied to the pad portion, the upper surface of the bonding layer melts. Pure tin remains on the upper surface of the bonding layer. Therefore, the pad portion can be easily bonded to the terminals of the chip, circuit board, and display panel.

[0149] Refer to Figure 12 , the metal layer 201 can include a first metal layer 201a and a second metal layer 201b. The first metal layer 201a is disposed on the buffer layer 205. The second metal layer 201b is disposed on the first metal layer 201a.

[0150] The thickness of the first metal layer 201a can be less than the thickness of the second metal layer 201b.

[0151] For example, the thickness of the first metal layer 201a can be 0.7 μm to 2 μm, and the thickness of the second metal layer 201b can be 10 μm to 25 μm.

[0152] The first metal layer 201a and the second metal layer 201b can contain the same metal material. For example, the first metal layer 201a and the second metal layer 201b can contain copper (Cu).

[0153] The first metal layer 201a and the second metal layer 201b can be formed by a plating process. For example, the first metal layer 201a is formed thinly on the buffer layer 205. Then, the first metal layer 201a can be used as a seed layer to form the second metal layer 201b.

[0154] In addition, the bonding layer 203 can include a first bonding layer 203a and a second bonding layer 203b.

[0155] The first bonding layer 203a is disposed on the metal layer 201. Specifically, the first bonding layer 203a is disposed on the first wiring portion 211, the first pad portion 212a, and the second pad portion 212b.

[0156] The second bonding layer 203b is disposed on the first bonding layer 203a. Specifically, the second bonding layer 203b is disposed on the first pad portion 212a and the second pad portion 212b.

[0157] Therefore, the first wiring portion 211 includes the buffer layer 205, the metal layer 201, and the first bonding layer 203a. In addition, the first pad portion 212a and the second pad portion 212b include the buffer layer 205, the metal layer 201, the first bonding layer 203a, and the second bonding layer 203b.

[0158] Therefore, the layer structure of the first wiring portion 211 is different from the layer structures of the first pad portion 212a and the second pad portion 212b.

[0159] The first bonding layer 203a and the second bonding layer 203b contain metal. Specifically, the first bonding layer 203a and the second bonding layer 203b may contain tin (Sn).

[0160] The first bonding layer 203a and the second bonding layer 203b are set to different thicknesses. Specifically, the thickness of the second bonding layer 203b is greater than the thickness of the first bonding layer 203a.

[0161] For example, the thickness of the first bonding layer 203a is 0.02 μm to 0.06 μm. Additionally, the thickness of the second bonding layer 203b is 0.2 μm to 0.6 μm.

[0162] Therefore, the thickness of the first wiring portion 211 becomes thinner. Therefore, when the flexible circuit board is bent, cracks in the first wiring portion 211 can be prevented.

[0163] The thickness of the first circuit pattern can be 2 μm to 25 μm. Specifically, the thickness of the first circuit pattern can be 5 μm to 20 μm. Specifically, the thickness of the first circuit pattern can be 7 μm to 15 μm.

[0164] If the thickness of the first circuit pattern is less than 2 μm, the resistance of the first circuit pattern may increase. If the thickness of the first circuit pattern exceeds 25 μm, it becomes difficult to achieve a fine pattern.

[0165] Hereinafter, reference will be made to Figures 13 to 23 Describe a flexible circuit board according to another embodiment. Descriptions that are the same as or similar to those of the flexible circuit board according to the foregoing embodiment will be omitted.

[0166] Refer to Figures 13 to 19 , the flexible circuit board 1000 includes a substrate 100, a circuit pattern, and protective layers 310 and 320.

[0167] Refer to Figure 16 and Figure 17 , metal patterns 250 and 260 are respectively provided on the first surface 1S and the second surface 2S. The metal patterns 250 and 260 are disposed adjacent to the first conduction portion V1. The metal patterns 250 and 260 are provided between the first conduction portion V1 and the end (E) of the substrate 100. The metal patterns 250 and 260 are provided between the first conduction portion V1 and the cutting line CL.

[0168] Refer to Figure 16 , the metal pattern 260 is provided on the second surface 2S. The metal pattern 260 is connected to the first conduction portion V1. Additionally, refer toFigure 18 , a metal pattern 250 is disposed on the first surface 1S. The metal pattern 250 is spaced apart from the first conduction part V1.

[0169] The metal pattern 260 may be a test pad. The metal pattern 260 can test for short circuits and shorts in the second circuit pattern 220.

[0170] The metal pattern 250 may be a dummy pattern. When the metal pattern 250 is connected to the first conduction part V1, the signal transmitted from the chip CH moves to the dummy pattern. Therefore, signal loss may occur. Therefore, the metal pattern 250 is spaced apart from the first conduction part V1.

[0171] The metal pattern 250 is spaced apart from the first conduction part V1 by a first distance d1.

[0172] The first distance d1 may be equal to or greater than the line width of the second wiring part 221 and equal to or less than the width of the first conduction part zone VL1 in the first direction. If the first distance d1 is less than the line width of the second wiring part 221, the metal pattern 250 may contact the first conduction part V1. Therefore, the first conduction part V1 and the metal pattern 250 may be electrically connected. Therefore, the signal generated from the chip is transmitted to the metal pattern 250, and signal loss and power loss may occur.

[0173] If the first distance d1 exceeds the width of the first conduction part zone VL1, the area where the metal pattern 250 is formed becomes narrower. Therefore, the area of the metal pattern 250 may be reduced. The metal pattern 250 may be a dummy pattern spaced apart from the second circuit pattern 220. Therefore, if the area of the metal pattern 250 is reduced, the strength of the flexible printed circuit board may be reduced. Thus, the flexible printed circuit board can be bent in one direction.

[0174] In another embodiment, the flexible printed circuit board is spaced apart from the second wiring part 221 and the metal pattern 250. Therefore, when the signal transmitted from the chip moves to the display panel, it is possible to prevent the signal from moving in the direction of the metal pattern. Therefore, signal loss of the flexible printed circuit board is reduced, and driving power is reduced.

[0175] In addition, since the second wiring part 221 and the metal pattern 250 are spaced apart, the reliability of the flexible printed circuit board is improved. The metal pattern 250 may extend to the cutting line CL. Therefore, the metal pattern 250 may be exposed to the outside. Therefore, corrosion may occur in the metal pattern 250.

[0176] Since the second wiring part 221 is spaced apart from the metal pattern 250, it is possible to prevent the corrosion of the metal pattern 250 from extending to the second wiring part 221. Therefore, corrosion of the second circuit pattern 220 is prevented. Therefore, it is possible to prevent a reduction in the electrical characteristics of the flexible printed circuit board and improve reliability.

[0177] In addition, since the metal pattern is provided between the second circuit pattern and the end portion of the substrate, the bending of the flexible printed circuit board is prevented. Since the metal pattern is provided at an interval from the second circuit pattern, the metal pattern is not connected to the chip. Since the metal pattern is provided between the second circuit pattern and the end portion of the substrate, the strength of the flexible printed circuit board is increased. That is to say, the metal pattern can be a dummy pattern. Since the strength of the flexible printed circuit board is increased by the metal pattern, the bending of the flexible printed circuit board is prevented.

[0178] Refer to Figure 17 , the second circuit pattern 220 on the first surface 1S is spaced apart from the cutting line CL. The flexible printed circuit board is cut along the cutting line CL. In addition, the second circuit pattern is spaced apart from the end portion of the substrate.

[0179] The minimum distance between the first conduction portion V1 and the cutting line CL is defined as the second pitch d2. The second pitch d2 can be 1 to 4 times, 1.5 to 3.5 times, or 2 to 3 times the width of the first conduction portion zone VL1 in the second direction.

[0180] If the second pitch d2 is less than 1 times the width of the first conduction portion zone V1, by-products generated when cutting the substrate along the cutting line CL may transfer to the second circuit pattern 220. Therefore, adjacent first conduction portions V1 may be short-circuited due to the by-products. Or, the conductivity of the second circuit pattern may be reduced.

[0181] In addition, if the second pitch d2 is greater than four times the width of the first conduction portion zone VL1, the border area of the flexible printed circuit board increases. Therefore, the size of the flexible printed circuit board increases.

[0182] Refer to Figure 19 , the second circuit pattern 220 on the first surface 1S can be surrounded by the first protective layer 310. Specifically, the first conduction portion V1 can be surrounded by the first protective layer 310.

[0183] The first protective layer 310 is provided between the metal pattern 250 and the first conduction portion V1. Specifically, the metal pattern 250 is spaced apart from the first conduction portion V1, and the first protective layer 310 is provided in the spaced area.

[0184] Therefore, even if the size of the first pitch d1 decreases during the process, contact between the second circuit pattern 220 and the metal pattern 250 can be prevented. In addition, since the first protective layer 310 is provided between the metal pattern 250 and the first conduction portion V1, corrosion transfer of the metal pattern 250 to the second circuit pattern 220 can be prevented.

[0185] In addition, since the metal pattern 250 is spaced apart from the first conduction part V1, the process of forming the first protective layer 310 becomes easy. The first protective layer 310 can be formed of a liquid material. Therefore, the liquid material can move to the separation region between the metal pattern 250 and the first conduction part V1. Accordingly, the movement path of the material for forming the first protective layer increases. Therefore, the process time for forming the first protective layer is reduced, and the thickness of the first protective layer becomes uniform.

[0186] Referring to Figure 20 , the line widths of the metal pattern 250 and the second wiring part 221 can be different. For example, the line width W1 of the metal pattern 250 can be greater than the line width W2 of the second wiring part 221. For example, the line width W1 of the metal pattern 250 can be 2 to 20 times, 3 to 15 times, or 5 to 10 times the line width W2 of the second wiring part 221. Alternatively, the line width W1 of the metal pattern 250 can be 1 to 3 times, 1.5 to 2.5 times, or 1.7 to 2.3 times the width of the first conduction part zone VL1 in the first direction.

[0187] Accordingly, the area of the metal pattern provided on the flexible circuit board increases. Accordingly, the strength of the flexible circuit board is improved, and the flexible circuit board can be prevented from being bent.

[0188] In addition, an excessive increase in the process time for forming the metal pattern 250 can be prevented. Accordingly, the process efficiency can be improved.

[0189] Referring to Figure 21 , the metal pattern 250 includes a plurality of metal patterns. The plurality of metal patterns can have different line widths. For example, the metal pattern 250 can include a first metal pattern 251, a second metal pattern 252, and a third metal pattern 253. The line widths of the first metal pattern 251, the second metal pattern 252, and the third metal pattern 253 can be different.

[0190] For example, the line width W1a of the first metal pattern 251 can be greater than the line width W1b of the second metal pattern 252 and the line width W1c of the third metal pattern 253. In addition, the line width W1b of the second metal pattern 252 can be greater than the line width W1c of the third metal pattern 253.

[0191] In Figure 21 , the first metal pattern 251, the second metal pattern 252, and the third metal pattern 253 are illustrated as being regularly arranged, but the embodiments are not limited thereto.

[0192] The metal pattern 250 has various line widths at various positions. Accordingly, the reliability of the flexible printed circuit board is improved. Specifically, due to the difference in the area of the patterns provided on the first surface and the second surface, the flexible printed circuit board can be bent in one direction. Accordingly, considering the difference in the area of the patterns, the metal pattern has different widths at various positions. Accordingly, bending of the flexible printed circuit board can be prevented.

[0193] Referring to Figure 22 and Figure 23 , the metal pattern 250 and the second wiring portion 221 can extend in different directions.

[0194] For example, referring to Figure 22 , the metal pattern 250 can extend in the first direction 1D. The second wiring portion 221 can extend in the second direction 2D. Specifically, the metal pattern 250 can extend in a direction perpendicular to the direction in which the second wiring portion 221 extends.

[0195] Alternatively, referring to Figure 23 , the metal pattern 250 can extend in a diagonal direction between the first direction 1D and the second direction 2D. The second wiring portion 221 can extend in the second direction 2D.

[0196] The metal pattern 250 can extend in various directions different from the direction in which the second wiring portion 221 extends. Accordingly, even when the area of the border region of the flexible printed circuit board is reduced, the metal pattern has a sufficient area. Specifically, when the number of terminals of the display panel increases, the number of second circuit patterns also increases. Accordingly, when the number of first conduction portions increases, the region where the metal pattern can be formed may become narrow. Accordingly, in the embodiment, dummy patterns are arranged to extend in various directions. Accordingly, even when the area of the border region is reduced, the metal pattern can have a sufficient area.

[0197] The flexible printed circuit board according to the embodiment can form a COF module by mounting a chip CH on a chip mounting region CHA and cutting a cutting line CL.

[0198] The COF module 2000 is connected to the display panel 4000 and the circuit board 3000. Accordingly, signals can be transmitted to the display panel 4000 and the circuit board 3000.

[0199] Referring to Figure 24, one end of the COF module 2000 is connected to the display panel 4000. The other end of the COF module 2000 is connected to the circuit board 3000. For example, the display panel 4000 can be disposed on one surface of the COF module 2000. Additionally, the circuit board 3000 can be disposed on the other surface of the COF module 2000. However, the embodiments are not limited thereto. The display panel 4000 and the circuit board 3000 can be disposed on the same surface of the COF module 2000.

[0200] The COF module 2000 includes a flexible substrate. Thus, it can have a rigid form and a bent form between the display panel 3000 and the circuit board 4000. That is to say, the COF module 2000 can include a bending region BA.

[0201] The COF module 2000 can connect the display panel 4000 and the circuit board 3000 in a bent form. Thus, the thickness of the electronic device can be reduced. Additionally, the degree of design freedom can be improved. Additionally, the wiring of the COF module 2000 will not be broken even in the bent form. Thus, the reliability of the electronic device including the COF module can be improved.

[0202] Since the COF module is flexible, it can be used in various electronic devices.

[0203] For example, referring to Figure 25 , the COF module can be applied to a bent flexible touch window. Thus, the touch device including the COF module can be a flexible touch device. Thus, the user can bend or fold it by hand.

[0204] Referring to Figure 26 , the COF module can be applied to various wearable touch devices including a curved display. Thus, the electronic device including the COF module can be thinned or lightened.

[0205] Referring to Figure 27 , the COF module can be applied to various electronic devices having a display unit, such as a television, a monitor, and a laptop computer.

[0206] The characteristics, structures, and effects described in the above embodiments are included in at least one embodiment, but not limited to one embodiment. In addition, those of ordinary skill in the art to which the embodiments pertain can even combine or modify the characteristics, structures, and effects shown in each embodiment for other embodiments. Therefore, it should be understood that the content related to such combinations and such modifications is included within the scope of the embodiments.

[0207] The above description focuses on the embodiments, but it is merely illustrative and does not limit the embodiments. Those skilled in the art to which the embodiments pertain will understand that various modifications and applications not shown above can be made without departing from the essential features of the embodiments. For example, each component specifically represented in the embodiments can be modified and implemented. In addition, it should be understood that the differences associated with such changes and applications are included within the scope of the embodiments defined in the appended claims.

Claims

1. A flexible printed circuit board, comprising: A substrate, the substrate including a first surface and a second surface opposite to the first surface; A first circuit pattern, the first circuit pattern being disposed on the first surface; A second circuit pattern, the second circuit pattern being disposed on the first surface and the second surface; And A third circuit pattern, the third circuit pattern being disposed on the first surface and the second surface, wherein the second circuit pattern includes a first conduction portion and a second wiring portion, wherein the third circuit pattern includes a second conduction portion and a third wiring portion, wherein the first conduction portion and the second conduction portion include a conduction portion area and via holes formed in the conduction portion area, wherein at least one of the first conduction portion and the second conduction portion defines a first pitch between the conduction portion areas, a second pitch between the conduction portion area and the second wiring portion or the third wiring portion adjacent to the conduction portion area, and a third pitch between a side surface of the conduction portion area and the via hole, and wherein at least one of the first pitch, the second pitch, and the third pitch is greater than the width of the wiring portion.

2. The flexible circuit board according to claim 1, wherein The first pitch is greater than 1 times the width of the wiring portion and less than or equal to 5 times the width of the wiring portion.

3. The flexible circuit board according to claim 1, wherein, The second pitch is greater than 1 times the width of the wiring portion and less than or equal to 3 times the width of the wiring portion.

4. The flexible circuit board according to claim 1, wherein, The third pitch is greater than 1 times the width of the wiring portion and less than or equal to 5 times the width of the wiring portion.

5. The flexible circuit board according to claim 1, wherein, The first pitch and the second pitch are different.

6. The flexible circuit board according to claim 5, wherein, The first pitch is 1.1 times to 5 times the second pitch.

7. The flexible circuit board according to claim 5, wherein, The first pitch is 12 μm to 30 μm, and wherein the second pitch is 3 μm to 11 μm.

8. The flexible circuit board according to claim 1, wherein, At least one corner portion of the conduction portion area includes a curved surface having a first radius of curvature.

9. A COF module, comprising: The flexible printed circuit board according to any one of claims 1 to 8; And A chip disposed in a chip mounting area of the flexible printed circuit board.

10. An electronic device, comprising: The COF module according to claim 9; A circuit board connected to the first circuit pattern; And A display panel connected to the second circuit pattern and the third circuit pattern.

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