Flexible printed circuit board, cof module, and electronic device including the cof module

Abstract

A flexible printed circuit board includes a substrate, a circuit pattern disposed on the substrate, a protective layer on the circuit pattern, the circuit pattern including a first circuit pattern connected with a chip in a chip mounting area and a second circuit pattern, a first direction and a second direction being defined in the substrate, the substrate including a first end and a second end facing each other in the first direction and a third end and a fourth end facing each other in the second direction, the protective layer including a fifth end and a sixth end spaced apart from the ends of the substrate and facing the first direction and a seventh end and an eighth end spaced apart from the ends of the substrate and facing the second direction, and including an external pattern disposed adjacent to the third end and the fourth end on the substrate, the external pattern including a first external pattern and a second external pattern adjacent to a pad portion of the first circuit pattern and facing the second direction, a third external pattern and a fourth external pattern adjacent to a pad portion of the second circuit pattern and facing the second direction.

Description

[0001] Cross-referencing of related patents

[0002] This application claims priority to Korean Patent Application No. 10-2021-0125888 (filed on September 23, 2021) pursuant to 35.119 and 35.365 of the United States Code, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments relate to a flexible printed circuit board, a COF module, and an electronic device including the COF module. Specifically, the flexible printed circuit board may be a flexible printed circuit board for use with COF. Background Technology

[0004] In recent years, various electronic products have become thinner, smaller, and lighter. Therefore, various researches are underway to install semiconductor chips at high density in the narrow areas of electronic products.

[0005] Among these methods, the chip-on-film (COF) approach, which uses flexible substrates, can be applied to both flat panel displays and flexible displays. In other words, the COF approach has attracted attention because it can be used in various wearable electronic devices. Furthermore, because the COF approach can achieve fine pixel pitch, it can be used to achieve high-resolution displays (QHD) as the number of pixels increases.

[0006] Chip-on-film (COF) is a method of mounting semiconductor chips in the form of a thin film on a flexible printed circuit board, where the semiconductor chip can be, for example, an integrated circuit (IC) chip or a large-scale integrated circuit (LSI) chip.

[0007] Simultaneously, the chip can be connected to an external PCB and display panel via wiring electrodes. For example, pads can be respectively located at one end and the other end of the wiring electrodes. One pad can be electrically connected to a terminal of the chip, while the other pad can be connected to a terminal of the PCB and a terminal of the display panel. Therefore, the chip, PCB, and display panel can be electrically connected via COF, and signals can be transmitted to the display panel via the wiring electrodes.

[0008] Simultaneously, a protective layer can be applied to the circuit pattern to protect the wiring electrodes. The protective layer helps prevent external impacts and contact with moisture and impurities, thereby improving the reliability of the COF.

[0009] Meanwhile, for connectivity, a protective layer may not be applied to the pad area, which is the area where the circuit pattern connects to the PCB and the display panel. When the protective layer is placed outside its designated position during the application process, the size of the pad area may increase unnecessarily, thus unnecessarily increasing the size of the COF.

[0010] Therefore, there is a need for a flexible printed circuit board with a new structure that can solve the above problems. Summary of the Invention

[0011] Technical issues

[0012] The embodiments are intended to provide a flexible printed circuit board with improved reliability, a COF module, and an electronic device including the COF module.

[0013] Technical solution

[0014] A flexible printed circuit board according to an embodiment includes: a substrate; a circuit pattern disposed on the substrate; and a protective layer disposed on the circuit pattern, wherein the circuit pattern includes a first circuit pattern and a second circuit pattern connected to a chip in a chip mounting region, defining a first direction and a second direction in the substrate, the first direction being a direction in which the circuit pattern extends, and the second direction being perpendicular to the first direction, the substrate including a first end and a second end facing each other in the first direction, and a third end and a fourth end facing each other in the second direction, the protective layer including a fifth end and a sixth end spaced apart from the ends of the substrate and facing the first direction, and a seventh end and an eighth end spaced apart from the ends of the substrate and facing the second direction, and the flexible printed circuit board including the third end and the second end facing each other on the substrate. The fourth end of the protective layer is provided with an external pattern adjacent to it. The external pattern includes: a first external pattern and a second external pattern, the first external pattern and the second external pattern being adjacent to the pad portion of the first circuit pattern and facing the second direction; and a third external pattern and a fourth external pattern, the third external pattern and the fourth external pattern being adjacent to the pad portion of the second circuit pattern and facing the second direction. The first external pattern includes a first pattern portion and a second pattern portion spaced apart from each other. The second external pattern includes a third pattern portion and a fourth pattern portion spaced apart from each other. The third external pattern includes a fifth pattern portion and a sixth pattern portion spaced apart from each other. The fourth external pattern includes a seventh pattern portion and an eighth pattern portion spaced apart from each other. The fifth end of the protective layer is provided between the first pattern portion and the second pattern portion and between the third pattern portion and the fourth pattern portion.

[0015] Beneficial effects

[0016] The flexible printed circuit board according to the embodiment may include a plurality of external patterns, and each external pattern may include a plurality of pattern portions spaced apart from each other.

[0017] Therefore, when setting a protective layer, the position of the protective layer in the first direction can be easily controlled.

[0018] That is, the position of the protective layer can be adjusted so that the end of the protective layer is positioned between the patterned parts. Therefore, the position of the protective layer can be easily controlled to the desired location through the patterned parts.

[0019] Therefore, it is possible to prevent the junction area of ​​the first and second circuit patterns from shrinking due to the protective layer being positioned outside the intended implementation location. Furthermore, it is possible to prevent areas in the wiring section where no protective layer is provided from occurring because the protective layer is positioned below the intended implementation location.

[0020] Therefore, the flexible printed circuit board according to the embodiment can easily control the position of the protective layer by means of multiple patterned portions formed on the outer pattern. Thus, the flexible printed circuit board according to the embodiment can improve bonding characteristics and have improved reliability by preventing corrosion of the circuit pattern. Attached Figure Description

[0021] Figure 1 This is a top view of a flexible printed circuit board according to an embodiment;

[0022] Figure 2 This is a top view of a flexible printed circuit board according to the first embodiment, with the circuit pattern omitted.

[0023] Figure 3 and 4 It is along Figure 1 A sectional view taken by line A-A' in the middle;

[0024] Figure 5 It is along Figure 1 A sectional view taken by line B-B' in the middle;

[0025] Figure 6 yes Figure 1 Various magnified views of region A in the image;

[0026] Figure 7 yes Figure 1 Various magnified views of region B in the image;

[0027] Figure 8 This is a top view of the flexible printed circuit board according to the second embodiment;

[0028] Figure 9 This is a top view of a flexible printed circuit board according to the second embodiment, with the circuit pattern omitted.

[0029] Figure 10 This is a top view of the COF module according to an embodiment;

[0030] Figure 11 This is a cross-sectional view showing the connection relationship of a COF module including a flexible printed circuit board according to an embodiment;

[0031] Figures 12 to 14 This is a view of an electronic device including a flexible printed circuit board according to an embodiment. Detailed Implementation

[0032] In the following, 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 the partial embodiments described, and may be implemented in various other forms. Furthermore, one or more elements of the embodiments may be selectively combined and substituted within the spirit and scope of the present disclosure.

[0033] Furthermore, unless otherwise explicitly defined and described, the terms (including technical and scientific terms) used in the embodiments of this disclosure may be interpreted as having the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and terms such as those defined in common dictionaries may be interpreted as having a meaning consistent with their meaning in the relevant context.

[0034] Furthermore, the terminology used in the embodiments of this disclosure is for illustrative purposes and is not intended to limit the scope of this disclosure. In this specification, unless specifically stated in the phrase, the singular form may also include the plural form, and may include at least one of all possible combinations of A, B, and C when described as “at least one (or more) A(and), B, and C”.

[0035] 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 elements from other elements, and are not limited to the nature, order, or sequence of the elements.

[0036] Furthermore, when an element is described as being “connected” or “coupled” to another element, it can include not only the element being directly “connected” or “coupled” to the other element, but also the element being “connected” or “coupled” to the other element by other elements between the element and the other element.

[0037] Furthermore, when described as being formed or disposed "above" or "below" each element, "above" or "below" can include not only two elements that are directly connected to each other, but also one or more other elements formed or disposed between the two elements.

[0038] Furthermore, when expressed as "above" or "below", it can include not only the upward direction but also the downward direction based on a single element.

[0039] In the following description, a flexible printed circuit board, a COF module, and an electronic device including the COF module according to embodiments will be described with reference to the accompanying drawings.

[0040] Figure 1 and Figure 2 This is a top view of a flexible printed circuit board according to an embodiment.

[0041] refer to Figure 1 and Figure 2 The flexible printed circuit board 1000 according to the embodiment may include a substrate 100 and a circuit pattern 200 disposed on the substrate 100.

[0042] Substrate 100 may include a flexible substrate. For example, substrate 100 may be a polyimide (PI) substrate. However, the embodiments are not limited thereto, and substrate 100 may include polymer materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc. Therefore, a flexible printed circuit board including substrate 100 can be used in various electronic devices with curved display devices. For example, a flexible printed circuit board including substrate 100 has excellent flexibility properties, thereby enabling the mounting of semiconductor chips for wearable electronic devices.

[0043] The substrate 100 may have a thickness of 20 μm to 100 μm. For example, the substrate 100 may have a thickness of 25 μm to 50 μm. For example, the substrate 100 may have a thickness of 30 μm to 40 μm. When the thickness of the substrate 100 exceeds 100 μm, the total thickness of the flexible printed circuit board may increase. Therefore, the flexibility may deteriorate. Furthermore, when the thickness of the substrate 100 is less than 20 μm, the substrate 100 may be more susceptible to the effects of heat / stress applied to the substrate 100 during chip mounting.

[0044] The substrate 100 may include a first region 1A and a second region 2A. For example, the first region 1A may be the central region of the substrate 100, and the second region 2A may be the outer region of the substrate 100. That is, the first region 1A may be disposed between the second regions 2A.

[0045] The first region 1A may include a chip mounting region CA. Specifically, the first region 1A may include a chip mounting region CA in which a chip C connected to a circuit pattern is mounted.

[0046] Furthermore, circuit patterns 210 and 220 can be disposed on the first region 1A. Specifically, multiple circuit patterns spaced apart from each other and extending in multiple directions can be disposed in the first region 1A.

[0047] The first region 1A can be the region actually used in the flexible printed circuit board 1000. That is, when the flexible printed circuit board comes into contact with another panel, the first region 1A can be the region in contact with the flexible printed circuit board.

[0048] The circuit pattern may not be set in the second region 2A. That is, the first region 1A and the second region 2A can be divided according to the presence or absence of the circuit pattern.

[0049] The second region 2A may include multiple holes. Specifically, the second region 2A may include multiple sprocket holes H. The flexible printed circuit board can be wound or unwound through the sprocket holes H in a roll-to-roll manner.

[0050] The second region 2A can be an area that is not actually used in the flexible printed circuit board 1000. That is, when the flexible printed circuit board comes into contact with another panel, the second region can be an area that needs to be removed.

[0051] In detail, after cutting the cutting line CL, which is defined as the boundary between the second region 2A and the first region 1A where the sprocket hole H is formed, the flexible printed circuit board 1000 can be processed into a COF module and installed on various electronic devices.

[0052] The circuit pattern may include wiring portions and pad portions. Furthermore, multiple circuit patterns may be disposed in the first region 1A. Specifically, the first circuit pattern 210 and the second circuit pattern 220 may be disposed in the first region 1A.

[0053] refer to Figure 1 , 3 4. The first circuit pattern 210 may include a first wiring portion 211, a first pad portion 212a, and a second pad portion 212b. Specifically, the first circuit pattern 210 may include a first pad portion 212a disposed inside the chip mounting region CA, a second pad portion 212b disposed outside the chip mounting region CA, and a first wiring portion 211 disposed between the first pad portion 212a and the second pad portion 212a and connected to the first pad portion 212a and the second pad portion 212b.

[0054] The first wiring section 211, the first pad section 212a, and the second pad section 212b can be integrally formed.

[0055] Furthermore, the first wiring section 211 can be configured to extend in the A1 direction A1 based on the chip mounting area CA.

[0056] The first pad portion 212a can be electrically connected to a chip disposed in the chip mounting area. Furthermore, the second pad portion 212b can be electrically connected to another printed circuit board. Additionally, the first wiring portion 211 can transmit signals between the chip and the printed circuit board.

[0057] The protective layer 300 may be disposed on the first circuit pattern 210. Specifically, the protective layer 300 may be disposed on the first wiring portion 211. The protective layer 300 may be disposed around the first wiring portion 211. Alternatively, the protective layer 300 may not be disposed on the first pad portion 212a and the second pad portion 212b.

[0058] Additionally, refer to Figure 1 and Figure 5 The second circuit pattern 220 may include a second wiring portion 221, a third pad portion 222a, and a fourth pad portion 222b. Specifically, the second circuit pattern 220 may include a third pad portion 222a disposed inside the chip mounting region CA, a fourth pad portion 222b disposed outside the chip mounting region CA, and a second wiring portion 221 disposed between and connected to the third pad portion 222a and the fourth pad portion 222b.

[0059] The second wiring section 221, the third pad section 222a, and the fourth pad section 222b can be integrally formed.

[0060] Furthermore, the second wiring portion 221 can be configured to extend in the A2 direction A2 based on the chip mounting region CA. More specifically, the second wiring portion 221 can be configured to extend in the A2 direction A2, which is opposite to the A1 direction A1.

[0061] The third pad portion 222a can be electrically connected to a chip disposed in the chip mounting area. Furthermore, the fourth pad portion 222b can be electrically connected to a display panel. Additionally, the second wiring portion 211 can transmit signals between the chip and the display panel.

[0062] The protective layer 300 may be disposed on the second circuit pattern 220. Specifically, the protective layer 300 may be disposed on the second wiring portion 221. The protective layer 300 may be disposed around the second wiring portion 221. Furthermore, the protective layer 300 may not be disposed on the third pad portion 222a and the fourth pad portion 222b.

[0063] Meanwhile, the protective layer 300 can be provided only at the designated location. When the protective layer 300 is provided outside the designated location, the area of ​​the pad portion may be reduced, and when the protective layer 300 is provided below the designated location, the wiring portion may not be effectively protected by the protective layer.

[0064] The arrangement of the protective layer 300 at the designated location will be described in detail below.

[0065] The first circuit pattern 210 and the second circuit pattern 220 may comprise a metallic material with excellent electrical conductivity. Specifically, the first circuit pattern 210 and the second circuit pattern 220 may comprise copper (Cu). However, the embodiments are not limited thereto, and the first circuit pattern 210 and the second circuit pattern 220 may comprise at least one metal selected from copper (Cu), aluminum (Al), chromium (Cr), nickel (Ni), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and their alloys.

[0066] In the following text, reference will be made to Figure 2 and Figure 3 The layer structure of the circuit pattern of a flexible printed circuit board according to an embodiment is described. Figure 2 and Figure 3 The text primarily describes the first circuit pattern 210, but the embodiments are not limited to this. Figure 2 and Figure 3 The description of the layer structure described in the previous section can also be applied similarly to the second circuit pattern 220.

[0067] refer to Figure 3 The first circuit pattern 210 can be formed as multiple layers. Specifically, the first wiring portion 211 and the first pad portion 212a may include a first metal layer 201 and a second metal layer 202. Furthermore, although... Figure 2 Although not shown, the second pad portion 212b may also include a first metal layer 201 and a second metal layer 202.

[0068] The first metal layer 201 may be a seed layer of the first circuit pattern 210. In detail, the first metal layer 201 may be a seed layer formed on the substrate 100 by chemical plating using a metal material such as copper (Cu).

[0069] Furthermore, the second metal layer 202 can be a plating layer. Specifically, the second metal layer 202 can be a plating layer formed by electroplating using the first metal layer 201 as a seed layer.

[0070] The thickness of the first metal layer 201 can be smaller than the thickness of the second metal layer 202.

[0071] For example, the thickness of the first metal layer 201 can be from 0.7 μm to 2 μm, and the thickness of the second metal layer 202 can be from 10 μm to 25 μm.

[0072] The first metal layer 201 and the second metal layer 202 may include the same metallic material. For example, the first metal layer 201 and the second metal layer 202 may contain copper (Cu).

[0073] Furthermore, the adhesive layer 203 may be disposed on the second metal layer 202. Specifically, the adhesive layer 203 may be disposed on the side surfaces of the first metal layer 201 and the second metal layer 202, as well as on the upper surface of the second metal layer 202. That is, the adhesive layer 203 may be disposed around the first metal layer 201 and the second metal layer 202.

[0074] The adhesive layer 203 may include metal. In particular, the adhesive layer 203 may include tin (Sn).

[0075] The adhesive layer 203 can be formed to have a thickness of 0.3 μm to 0.7 μm. The tin content of the adhesive layer 203 can be increased as it extends from the lower surface of the adhesive layer 203 and the second metal layer 202 that are in contact with each other toward their upper surface.

[0076] That is, since the adhesive layer 203 is configured to contact the second metal layer 202, the tin content can be increased and the copper content can be decreased from the lower surface of the adhesive layer 203 toward its upper surface.

[0077] Therefore, only pure tin can remain on the upper surface of the adhesive layer 203 within a thickness range of 0.1 μm to 0.3 μm.

[0078] The terminals of the chip, printed circuit board, and display panel can be easily adhered to the first pad and the second pad via the adhesive layer 203 through heat and pressure. That is, when heat and pressure are applied to the first pad and the second pad, the first pad and the second pad can be easily adhered to the terminals of the chip, printed circuit board, and display panel while the upper surface of the adhesive layer containing pure tin melts.

[0079] Therefore, the adhesive layer 203 may not be separated from the first pad portion 212a and may become part of the first pad portion.

[0080] The first circuit pattern 210 can be provided with a thickness of 2μm to 25μm. For example, the first circuit pattern 210 can be provided with a thickness of 5μm to 20μm. For example, the first circuit pattern 210 can be provided with a thickness of 7μm to 15μm.

[0081] Since the first metal layer 201 is etched by flash etching to separate the circuit pattern during the manufacturing process of the first circuit pattern 210, the final manufactured first circuit pattern 210 and second circuit pattern 220 can be smaller than the sum of the thicknesses of the first metal layer 201, the second metal layer 202 and the adhesive layer 203.

[0082] When the thickness of the first circuit pattern 210 and the second circuit pattern 220 is less than 2 μm, the resistance of the first circuit pattern 210 and the second circuit pattern 220 may increase. When the thickness of the first circuit pattern 210 and the second circuit pattern 220 exceeds 25 μm, it may be difficult to achieve fine patterns.

[0083] Meanwhile, a buffer layer 205 can be further provided between the substrate 100 and the first circuit pattern 210 and the second circuit pattern 220. The buffer layer 205 can improve the adhesion between the substrate 100 of different materials and the first circuit pattern 210 and the second circuit pattern 220.

[0084] The buffer layer 205 can be formed in multiple layers. Specifically, a first buffer layer 205a and a second buffer layer 205b on the first buffer layer 205a can be disposed on the substrate 100. Therefore, the first buffer layer 205a can contact the substrate 100, and the second buffer layer 205b can be configured to contact the first circuit pattern 210.

[0085] The first buffer layer 205a may contain a material that has good adhesion to the substrate 100. For example, the first buffer layer 205a may contain nickel (Ni). Furthermore, the second buffer layer 205b may contain a material that has good adhesion to the first circuit pattern 210. For example, the second buffer layer 205b may contain chromium (Cr).

[0086] The buffer layer 205, which includes the first buffer layer 205a and the second buffer layer 205b, can have a film thickness in nanometers. For example, the buffer layer 205 can have a thickness of 20 nm or less.

[0087] The buffer layer 205 can improve the adhesion between the substrate 100 of different materials and the first circuit pattern 210, thereby preventing the first circuit pattern 210 from detaching.

[0088] At the same time, refer to Figure 4 The adhesive layer 203 may include a first adhesive layer 203a and a second adhesive layer 203b.

[0089] Specifically, the first adhesive layer 203a can be disposed on the first wiring portion 211 and the first pad portion 212a. Furthermore, although not shown in the drawings, the first adhesive layer 203a can also be disposed on the second pad portion 212b. That is, the first adhesive layer 203a can be disposed on the first circuit pattern 210.

[0090] Furthermore, the second adhesive layer 203b may be provided only on the first pad portion 212a and the second pad portion 212b. That is, the first wiring portion 211, the first pad portion 212a and the second pad portion 212b may have different layer structures due to the second adhesive layer 203b.

[0091] The first adhesive layer 203a and the second adhesive layer 203b may include metal. Specifically, the first adhesive layer 203a and the second adhesive layer 203b may include tin (Sn).

[0092] The first adhesive layer 203a and the second adhesive layer 203b can be configured to have different thicknesses. Specifically, the thickness of the second adhesive layer 203b can be greater than the thickness of the first adhesive layer 203a.

[0093] For example, the first adhesive layer 203a may have a film thickness of 0.02 μm to 0.06 μm, and the second adhesive layer 203b may have a thickness of 0.2 μm to 0.6 μm.

[0094] When the adhesive layer is relatively thick between the protective layer 300 and the first wiring portion 211, cracks may occur when the flexible printed circuit board is bent. Therefore, by forming the first adhesive layer 203a between the protective layer 300 and the first wiring portion 211 to have a thin film thickness, cracks can be prevented when the flexible printed circuit board is bent.

[0095] Furthermore, the second adhesive layer 203b can have a higher tin content while extending from the lower surface of the second adhesive layer 203b and the first adhesive layer 203a that are in contact with each other toward their upper surface.

[0096] That is, in the second adhesive layer 203b, the tin content can be increased and the copper content can be decreased in the direction from the lower surface of the second adhesive layer 203b toward its upper surface.

[0097] Therefore, only pure tin can remain on the upper surface of the second adhesive layer 203b in a thickness range of 0.1 μm to 0.3 μm.

[0098] The terminals of the chip, printed circuit board, and display panel can be easily adhered to the first pad and the second pad via heat and pressure through the second adhesive layer 203b. That is, when heat and pressure are applied to the first pad and the second pad, the first pad and the second pad can be easily adhered to the terminals of the chip, printed circuit board, and display panel while the upper surface of the adhesive layer containing pure tin melts.

[0099] Therefore, the first adhesive layer 203a and the second adhesive layer 203b can remain separate from the first pad portion 212a and can become part of the first pad portion.

[0100] Meanwhile, the protective layer 300 can be disposed on the wiring portions of the first circuit pattern 210 and the second circuit pattern 220. Specifically, the protective layer 300 can be disposed around the first wiring portion 211 and the second wiring portion 221. That is, the protective layer 300 can be disposed on the first circuit pattern 210 and the second circuit pattern 220 except for the first pad portion, the second pad portion, the third pad portion, and the fourth pad portion.

[0101] The protective layer 300 may include solder paste. For example, the protective layer 300 may include solder paste comprising a thermosetting resin, a thermoplastic resin, a filler, a curing agent, or a curing accelerator.

[0102] As described above, the protective layer 300 can be disposed on areas other than the first pad portion 212a, the second pad portion 212b, the third pad portion 222a, and the fourth pad portion 222b. The second pad portion 212b and the fourth pad portion 222b can be areas where the flexible printed circuit board connects to an external printed circuit board and a display panel. That is, the substrate 100 can include bonding areas, and the second pad portion 212b and the fourth pad portion 222b can be disposed in the bonding areas respectively.

[0103] In this situation, when the protective layer 300 is not positioned at the designated location or is located outside the designated location, the protective layer 300 is positioned to the bonding area of ​​the substrate 100, which may reduce the area of ​​the bonding area. Therefore, the bonding reliability of the printed circuit board and the display panel may deteriorate due to the reduction in the area of ​​the bonding area. Alternatively, to adequately ensure the bonding area, the size of the flexible printed circuit board may need to be unnecessarily increased.

[0104] In addition, when the protective layer 300 is not set at the set position but below the set position, the protective layer is not set to completely cover the wiring section. Therefore, deformation of the wiring section, such as corrosion, may occur in the wiring section area where the protective layer is not set.

[0105] The following section describes a flexible printed circuit board with a novel structure that addresses the aforementioned problems.

[0106] refer to Figure 1 and 2 The substrate 100 may include multiple ends. Here, the ends of the substrate 100 may be defined as regions extending along a cutting line CL, which is the boundary between a first region 1A and a second region 2A of the substrate.

[0107] In detail, the substrate 100 may include a first end E1, a second end E2, a third end E3, and a fourth end E4. For example, the substrate 100 may include a first end E1 and a second end E2, as well as a third end E3 and a fourth end E4, wherein the first end E1 and the second end E2 are arranged to face each other in the direction in which the first circuit pattern 210 and the second circuit pattern 220 extend, and the third end E3 and the fourth end E4 are connected to the first end E1 and the second end E2.

[0108] The first end E1, the second end E2, the third end E3, and the fourth end E4 can extend along the cutting line CL.

[0109] Hereinafter, the direction in which the first end E1 and the second end E2 face each other is defined as the first direction 1D, and the direction in which the third end E3 and the fourth end E4 face each other is defined as the second direction 2D.

[0110] For example, the first direction 1D can be defined as the direction in which the first circuit pattern 210 and the second circuit pattern 220 extend. The first direction 1D can be defined as the direction in which the pad portions of the first circuit pattern face each other. Alternatively, the first direction 1D can be defined as the direction in which the pad portions of the second circuit pattern face each other. Alternatively, the first direction 1D can be defined as the direction in which the bonding regions of the first and second circuit patterns face each other.

[0111] Furthermore, the first direction 1D and the second direction 2D can be perpendicular to each other.

[0112] Furthermore, the protective layer 300 may include multiple ends. Specifically, the protective layer 300 may include a fifth end E5, a sixth end E6, a seventh end E7, and an eighth end E8. For example, the protective layer 300 may include a fifth end E5 spaced apart from the first end E1 of the substrate 100 and positioned directly facing each other; a sixth end E6 spaced apart from the second end E2 of the substrate 100 and positioned directly facing each other; a seventh end E7 spaced apart from the third end E3 of the substrate 100 and positioned directly facing each other; and an eighth end E8 spaced apart from the fourth end E4 of the substrate 100 and positioned directly facing each other.

[0113] Furthermore, the fifth end E5 and the sixth end E6 can be configured to face each other, and the seventh end E7 and the eighth end E8 can be connected to the fifth end E5 and the sixth end E6 respectively and configured to face each other.

[0114] That is, the fifth end E5 and the sixth end E6 can be arranged to face each other in the first direction 1D, and the seventh end E7 and the eighth end E8 can be arranged to face each other in the second direction 2D.

[0115] The flexible printed circuit board 1000 may include external patterns adjacent to the ends. Specifically, the flexible printed circuit board 1000 may include multiple external patterns adjacent to the third end E3 and the fourth end E4. The external patterns may be the patterns positioned closest to the third end E3 and the fourth end E4. Alternatively, the external patterns may be patterns disposed within the patterns positioned closest to the third end E3 and the fourth end E4. Furthermore, the external patterns may be circuit patterns or dummy patterns. Specifically, the external patterns may be at least one of a first circuit pattern 210 and a second circuit pattern 220 connected to a chip. Alternatively, the external patterns may be dummy patterns not connected to a chip.

[0116] For example, the outer pattern may include a first outer pattern OP1, a second outer pattern OP2, a third outer pattern OP3, and a fourth outer pattern OP4.

[0117] The first outer pattern OP1 may be adjacent to the third end E3, and the second outer pattern OP2 may be adjacent to the fourth end E4. Furthermore, the first outer pattern OP1 and the second outer pattern OP2 may be arranged to face each other in the second direction 2D.

[0118] Furthermore, the first external pattern OP1 and the second external pattern OP2 can be configured to be adjacent to the pad portion of the first circuit pattern. That is, the first external pattern OP1 and the second external pattern OP2 can be configured to be adjacent to the bonding area of ​​the first circuit pattern.

[0119] Furthermore, the third outer pattern OP3 may be adjacent to the third end E3, and the fourth outer pattern OP4 may be adjacent to the fourth end E4. Additionally, the third outer pattern OP3 and the fourth outer pattern OP4 may be positioned facing each other in the second direction 2D.

[0120] Furthermore, the third outer pattern OP3 and the fourth outer pattern OP4 can be configured to be adjacent to the pad portion of the second circuit pattern. That is, the third outer pattern OP3 and the fourth outer pattern OP4 can be configured to be adjacent to the bonding area of ​​the second circuit pattern.

[0121] Furthermore, the first outer pattern OP1 and the third outer pattern OP3 can be spaced apart from each other in the first direction 1D. That is, the first outer pattern OP1 and the third outer pattern OP3 can be arranged to face each other in the first direction 1D.

[0122] Furthermore, the second outer pattern OP2 and the fourth outer pattern OP4 can be spaced apart from each other in the first direction 1D. That is, the second outer pattern OP2 and the fourth outer pattern OP4 can be arranged to face each other in the first direction 1D.

[0123] At least one of the first outer pattern OP1, the second outer pattern OP2, the third outer pattern OP3, and the fourth outer pattern OP4 may include a pattern part.

[0124] In detail, the first outer pattern OP1, the second outer pattern OP2, the third outer pattern OP3 and the fourth outer pattern OP4 may each include at least one pattern part.

[0125] The first outer pattern OP1 may include multiple pattern portions. Specifically, the first outer pattern OP1 may include a first pattern portion P1 and a second pattern portion P2. The first pattern portion P1 and the second pattern portion P2 may be configured to extend in one direction. Furthermore, the first pattern portion P1 and the second pattern portion P2 may be configured to extend in the same direction. That is, the first pattern portion P1 and the second pattern portion P2 may be embossed portions extending and protruding from the first outer pattern OP1 in one direction.

[0126] For example, the first pattern portion P1 and the second pattern portion P2 can be configured to extend outward. That is, the first pattern portion P1 and the second pattern portion P2 can be configured to extend in the direction of the third end portion E3 of the substrate 100.

[0127] The first pattern portion P1 and the second pattern portion P2 can be configured to be spaced apart from each other. Specifically, the first pattern portion P1 and the second pattern portion P2 can be configured to be spaced apart from each other in the first direction 1D. Furthermore, the fifth end portion E5 of the protective layer 300 can pass through the space between the first pattern portion P1 and the second pattern portion P2. That is, the fifth end portion E5 of the protective layer 300 can be disposed between the first pattern portion P1 and the second pattern portion P2.

[0128] The first pattern portion P1 and the second pattern portion P2 can be configured to be spaced apart from each other by a predetermined size in the first direction 1D. Specifically, the first interval S1 between the first pattern portion P1 and the second pattern portion P2 can be 300 μm or less. More specifically, the first interval S1 between the first pattern portion P1 and the second pattern portion P2 can be from 100 μm to 300 μm.

[0129] When the first interval S1 exceeds 300μm or is less than 100μm, the distance between the first pattern portion P1 and the second pattern portion P2 becomes too large or too small, so the position of the end of the protective layer cannot be easily and accurately controlled.

[0130] Furthermore, the first pattern portion P1 and the second pattern portion P2 may have a length L1 and a width W1 of a predetermined size. For example, the length L1 and the width W1 of the first pattern portion P1 and the second pattern portion P2 may be 20 μm to 50 μm.

[0131] When the length Ll and width Wl of the first pattern part P1 and the second pattern part P2 are less than 20 μm, the first pattern part P1 and the second pattern part P2 may not be easy to implement. When the length Ll and width Wl of the first pattern part P1 and the second pattern part P2 exceed 50 μm, the spacing between the first pattern part P1 and the second pattern part P2 and another adjacent circuit pattern or dummy pattern becomes narrower, which may cause short circuits and thus degrade the electrical characteristics.

[0132] The second outer pattern OP2 may include multiple pattern portions. Specifically, the second outer pattern OP2 may include a third pattern portion P3 and a fourth pattern portion P4. The third pattern portion P3 and the fourth pattern portion P4 may be configured to extend in one direction. Furthermore, the third pattern portion P3 and the fourth pattern portion P4 may be configured to extend in the same direction. That is, the third pattern portion P3 and the fourth pattern portion P4 may be relief portions extending and protruding from the second outer pattern OP2 in one direction.

[0133] Furthermore, the third pattern portion P3 and the fourth pattern portion P4 can be configured to extend in the same or opposite direction as the first pattern portion P1 and the second pattern portion P2.

[0134] For example, the third pattern portion P3 and the fourth pattern portion P4 can be configured to extend outward. That is, the third pattern portion P3 and the fourth pattern portion P4 can be configured to extend in the direction of the fourth end portion E4 of the substrate 100.

[0135] The third pattern portion P3 and the fourth pattern portion P4 can be spaced apart from each other. Specifically, the third pattern portion P3 and the fourth pattern portion P4 can be spaced apart from each other in the first direction 1D. Furthermore, the fifth end portion E5 of the protective layer 300 can pass through the space between the third pattern portion P3 and the fourth pattern portion P4. That is, the fifth end portion E5 of the protective layer 300 can be disposed between the third pattern portion P3 and the fourth pattern portion P4. In other words, the fifth end portion E5 of the protective layer 300 can be disposed between the first pattern portion P1 and the second pattern portion P2, and between the third pattern portion P3 and the fourth pattern portion P4.

[0136] The third pattern portion P3 and the fourth pattern portion P4 can be configured to be spaced apart from each other by a set size in the first direction 1D. Specifically, the second interval S2 between the third pattern portion P3 and the fourth pattern portion P4 can be 300 μm or less. More specifically, the second interval S2 between the third pattern portion P3 and the fourth pattern portion P4 can be from 100 μm to 300 μm.

[0137] Furthermore, the second interval S2 may have the same or similar dimensions as the first interval S1 within the aforementioned range.

[0138] When the second interval S2 exceeds 300μm or is less than 100μm, the distance between the third pattern portion P3 and the fourth pattern portion P4 becomes too large or too small, making it impossible to easily and accurately control the position of the end of the protective layer.

[0139] Furthermore, the third pattern portion P3 and the fourth pattern portion P4 can have a length L2 and a width W2 of a predetermined size. For example, the length L2 and the width W2 of the third pattern portion P3 and the fourth pattern portion P4 can be from 20 μm to 50 μm.

[0140] Furthermore, the length L2 and width W2 of the third pattern part P3 and the fourth pattern part P4 can be the same as or similar to the length L1 and width W1 of the first pattern part P1 and the second pattern part P2 within the aforementioned range.

[0141] When the length L2 and width W2 of the third pattern part P3 and the fourth pattern part P4 are less than 20 μm, the third pattern part P3 and the fourth pattern part P4 may not be easy to implement. When the length L2 and width W2 of the third pattern part P3 and the fourth pattern part P4 exceed 50 μm, the spacing between the third pattern part P3 and the fourth pattern part P4 and another adjacent circuit pattern or dummy pattern becomes narrower, which may cause short circuits and thus deteriorate the electrical characteristics.

[0142] The third outer pattern OP3 may include multiple pattern portions. Specifically, the third outer pattern OP3 may include a fifth pattern portion P5 and a sixth pattern portion P6. The fifth pattern portion P5 and the sixth pattern portion P6 may be configured to extend in one direction. Furthermore, the fifth pattern portion P5 and the sixth pattern portion P6 may be configured to extend in the same direction. That is, the fifth pattern portion P5 and the sixth pattern portion P6 may be relief portions extending and protruding from the third outer pattern OP3 in one direction.

[0143] For example, the fifth pattern portion P5 and the sixth pattern portion P6 can be configured to extend inward. That is, the fifth pattern portion P5 and the sixth pattern portion P6 can be configured to extend in the direction of the third end portion E3 of the substrate 100.

[0144] The fifth pattern portion P5 and the sixth pattern portion P6 can be arranged to be spaced apart from each other. Specifically, the fifth pattern portion P5 and the sixth pattern portion P6 can be arranged to be spaced apart from each other in the first direction 1D. Furthermore, the sixth end portion E6 of the protective layer 300 can pass through the space between the fifth pattern portion P5 and the sixth pattern portion P6. That is, the sixth end portion E6 of the protective layer 300 can be disposed between the fifth pattern portion P5 and the sixth pattern portion P6.

[0145] The fifth pattern portion P5 and the sixth pattern portion P6 can be configured to be spaced apart from each other by a set size in the first direction 1D. Specifically, the third interval S3 between the fifth pattern portion P5 and the sixth pattern portion P6 can be 300 μm or less. More specifically, the third interval S3 between the fifth pattern portion P5 and the sixth pattern portion P6 can be from 100 μm to 300 μm.

[0146] Furthermore, the third interval S3 may have the same or similar dimensions as the first interval S1 and the second interval S2 within the aforementioned range.

[0147] When the third interval S3 exceeds 300μm or is less than 100μm, the distance between the fifth pattern part P5 and the sixth pattern part P6 becomes too large or too small, making it impossible to easily and accurately control the position of the end of the protective layer.

[0148] Furthermore, the fifth pattern section P5 and the sixth pattern section P6 may have a length L3 and a width W3 of a predetermined size. For example, the length L3 and the width W3 of the fifth pattern section P5 and the sixth pattern section P6 may be from 20 μm to 50 μm.

[0149] Furthermore, the length L3 and width W3 of the fifth pattern part P5 and the sixth pattern part P6 may be the same as or similar to the length L1 and width W1 of the first pattern part P1 and the second pattern part P2, as well as the length L2 and width W2 of the third pattern part P3 and the fourth pattern part P4, within the aforementioned range.

[0150] When the length L3 and width W3 of the fifth pattern part P5 and the sixth pattern part P6 are less than 20 μm, the fifth pattern part P5 and the sixth pattern part P6 may be difficult to implement. When the length L3 and width W3 of the fifth pattern part P5 and the sixth pattern part P6 exceed 50 μm, the spacing between the fifth pattern part P5 and the sixth pattern part P6 and another adjacent circuit pattern or dummy pattern becomes narrower, which may cause short circuits and thus deteriorate the electrical characteristics.

[0151] The fourth outer pattern OP4 may include multiple pattern portions. Specifically, the fourth outer pattern OP4 may include a seventh pattern portion P7 and an eighth pattern portion P8. The seventh pattern portion P7 and the eighth pattern portion P8 may be configured to extend in one direction. Furthermore, the seventh pattern portion P7 and the eighth pattern portion P8 may be configured to extend in the same direction. That is, the seventh pattern portion P7 and the eighth pattern portion P8 may be relief portions extending and protruding from the fourth outer pattern OP4 in one direction.

[0152] Furthermore, the seventh pattern section P7 and the eighth pattern section P8 can be configured to extend in the same or opposite direction as the fifth pattern section P5 and the sixth pattern section P6.

[0153] For example, the seventh pattern portion P7 and the eighth pattern portion P8 can be configured to extend inward. That is, the seventh pattern portion P7 and the eighth pattern portion P8 can be configured to extend in the direction of the fourth end portion E4 of the substrate 100.

[0154] The seventh pattern portion P7 and the eighth pattern portion P8 can be spaced apart from each other. Specifically, the seventh pattern portion P7 and the eighth pattern portion P8 can be spaced apart from each other in the first direction 1D. Furthermore, the sixth end portion E6 of the protective layer 300 can pass through the space between the seventh pattern portion P7 and the eighth pattern portion P8. That is, the sixth end portion E6 of the protective layer 300 can be disposed between the seventh pattern portion P7 and the eighth pattern portion P8. In other words, the sixth end portion E6 of the protective layer 300 can be disposed between the fifth pattern portion P5 and the sixth pattern portion P6, and between the seventh pattern portion P7 and the eighth pattern portion P8.

[0155] The seventh pattern portion P7 and the eighth pattern portion P8 can be configured to be spaced apart from each other by a set size in the first direction 1D. Specifically, the fourth interval S4 between the seventh pattern portion P7 and the eighth pattern portion P8 can be 300 μm or less. More specifically, the fourth interval S4 between the seventh pattern portion P7 and the eighth pattern portion P8 can be from 100 μm to 300 μm.

[0156] Furthermore, the fourth interval S4 may have a size that is equal to or similar to that of the first interval S1, the second interval S2, and the third interval S3 within the aforementioned range.

[0157] When the fourth interval S4 exceeds 300μm or is less than 100μm, the distance between the seventh pattern part P7 and the eighth pattern part P8 becomes too large or too small, making it impossible to easily and accurately control the position of the end of the protective layer.

[0158] Furthermore, the seventh pattern section P7 and the eighth pattern section P8 may have a length L4 and a width W4 of a predetermined size. For example, the length L4 and the width W4 of the seventh pattern section P7 and the eighth pattern section P8 may be 20 μm to 50 μm.

[0159] Furthermore, the length L4 and width W4 of the seventh pattern part P7 and the eighth pattern part P8 can be equal to or similar to the length L1 and width W1 of the first pattern part P1 and the second pattern part P2, the length L2 and width W2 of the third pattern part P3 and the fourth pattern part P4, and the length L3 and width W3 of the fifth pattern part P5 and the sixth pattern part P6.

[0160] When the length L4 and width W4 of the seventh pattern part P7 and the eighth pattern part P8 are less than 20 μm, the seventh pattern part P7 and the eighth pattern part P8 may not be easy to implement. When the length L4 and width W4 of the seventh pattern part P7 and the eighth pattern part P8 exceed 50 μm, the spacing between the seventh pattern part P7 and the eighth pattern part P8 and another adjacent circuit pattern or dummy pattern becomes narrower, which may cause short circuits and thus deteriorate the electrical characteristics.

[0161] The flexible printed circuit board according to the first embodiment may include a plurality of external patterns, and each external pattern may include a plurality of pattern portions spaced apart from each other.

[0162] Therefore, when the protective layer 300 is set, the position of the protective layer in the first direction can be easily controlled.

[0163] That is, the position of the protective layer can be adjusted so that the end of the protective layer 300 is positioned between the patterned portions. Therefore, the position of the protective layer can be easily controlled to the position to be achieved by the patterned portions.

[0164] Therefore, it is possible to prevent the junction area of ​​the first and second circuit patterns from shrinking due to the protective layer being positioned outside the desired location. Furthermore, it is possible to prevent areas in the wiring section where no protective layer is provided from appearing because the protective layer is positioned below the desired location.

[0165] Therefore, the flexible printed circuit board according to the embodiment can easily control the position of the protective layer by means of multiple patterned portions formed on the outer pattern. Thus, the flexible printed circuit board according to the embodiment can improve bonding characteristics and has improved reliability by preventing corrosion of the circuit pattern.

[0166] Meanwhile, in the above description, the pattern portion of the outer pattern has been described as being formed as an embossed shape extending in one direction, but the embodiments are not limited to this.

[0167] Figure 6 These are views used to illustrate the various shapes of the patterned portion of the first outer pattern OP1. Although in Figure 6 The shape of the pattern portion of the first outer pattern OP1 is only shown in the figure, but it can be similarly applied to the pattern portion of the second outer pattern OP2 facing the first outer pattern OP1 in the second direction.

[0168] refer to Figure 6 The first pattern portion P1 and the second pattern portion P2 of the first outer pattern OP1 can be formed into the shape of an engraved portion formed in the inner region of the first outer pattern OP1. Figure 6 (a) in the middle.

[0169] Or, refer to Figure 6 Either the first pattern part P1 and the second pattern part P2 of the first outer pattern OP1 can be formed in the shape of a relief part, while the other pattern part can be formed in the shape of an engraved part. Figure 6 (b) in the middle.

[0170] Or, refer to Figure 6 The first pattern portion P1 and the second pattern portion P2 of the first outer pattern OP1 can be formed as relief portions protruding and extending in the direction of the fourth end point E4 of the substrate 100. Alternatively, in the case of the second outer pattern OP2, the third pattern portion P3 and the fourth pattern portion P4 can be formed as relief portions protruding and extending in the direction of the third end point E3 of the substrate 100. Figure 6 (c) in the middle.

[0171] Or, refer to Figure 6 Either the first pattern portion P1 or the second pattern portion P2 of the first outer pattern OP1 can protrude in the direction of the third end E3 of the substrate 100, while the other pattern portion can protrude in the direction of the fourth end of the substrate 100. That is, the multiple pattern portions of the outer pattern can be configured to extend in different directions. Figure 6 (d) in the middle.

[0172] Figure 7 These are views of various shapes used to describe the pattern section of the third outer pattern OP3. Although in Figure 7 The shape of the pattern portion of the third outer pattern OP3 is only shown in the figure, but it can also be similarly applied to the pattern portion of the fourth outer pattern OP4 facing the third outer pattern OP3 in the second direction.

[0173] refer to Figure 7 The fifth pattern part P5 and the sixth pattern part P6 of the third outer pattern OP3 can be formed into the shape of an engraved part formed in the inner region of the third outer pattern OP3. Figure 7 (a) in the middle.

[0174] Or, refer to Figure 7 Either the fifth pattern part P5 or the sixth pattern part P6 of the third outer pattern OP3 can be formed as a relief part, while the other pattern part can be formed as an engraved part. Figure 7 (b) in the middle.

[0175] Or, refer to Figure 7The fifth pattern portion P5 and the sixth pattern portion P6 of the third outer pattern OP3 can be formed as relief portions protruding and extending in the direction of the third end point E3 of the substrate 100. Alternatively, in the case of the fourth outer pattern OP4, the seventh pattern portion P7 and the eighth pattern portion P8 can be formed as relief portions protruding and extending in the direction of the fourth end point E4 of the substrate 100. Figure 7 (c) in the middle.

[0176] Or, refer to Figure 7 Either the fifth pattern portion P5 or the sixth pattern portion P6 of the third outer pattern OP3 can protrude in the direction of the third end E3 of the substrate 100, while the other pattern portion can protrude in the direction of the fourth end of the substrate 100. That is, the multiple pattern portions of the outer pattern can be configured to extend in different directions. Figure 7 (d) in the middle.

[0177] Meanwhile, the first pattern part P1, the second pattern part P2, the third pattern part P3, the fourth pattern part P4, the fifth pattern part P5, the sixth pattern part P6, the seventh pattern part P7 and the eighth pattern part P8 can extend in the direction of the circuit pattern or dummy pattern adjacent to the external pattern.

[0178] In this case, the pattern portion of the outer pattern can be set to be spaced apart from adjacent patterns by a predetermined interval to prevent short circuits between the outer pattern and adjacent circuit patterns or dummy patterns. Specifically, at least one of the first pattern portion P1, the second pattern portion P2, the third pattern portion P3, the fourth pattern portion P4, the fifth pattern portion P5, the sixth pattern portion P6, the seventh pattern portion P7, and the eighth pattern portion P8 can be spaced apart from the circuit patterns or dummy patterns adjacent to the outer pattern by a interval of 20 μm or less, preferably by a interval of 15 μm or less, and more preferably by a interval of 10 μm or less.

[0179] Therefore, short circuits between the pattern portion of the outer pattern and adjacent patterns can be prevented.

[0180] In the following text, reference will be made to Figure 8 and Figure 9 A flexible printed circuit board according to a second embodiment is described.

[0181] refer to Figure 8 and Figure 9 Unlike the first embodiment described above, the flexible printed circuit board according to the second embodiment may further include a fifth external pattern OP5, a sixth external pattern OP6, a seventh external pattern OP7, and an eighth external pattern OP8.

[0182] Furthermore, the flexible printed circuit board 1000 may include a protective layer formed of two layers. Specifically, the flexible printed circuit board 1000 may include a first protective layer 310 and a second protective layer 320 on the first protective layer 310.

[0183] For example, the first protective layer 310 can be disposed at the same location as the protective layer 300 described above. That is, the first protective layer 310 can be disposed on the wiring portion of the circuit pattern. Furthermore, the second protective layer 320 can be disposed on the bending region of the flexible printed circuit board 1000. Specifically, the second protective layer 320 can be disposed on the bending region adjacent to the folding axis formed when the flexible printed circuit board is folded.

[0184] The second protective layer 320 may include multiple ends. Specifically, the second protective layer 320 may include a ninth end E9, a tenth end E10, an eleventh end E11, and a twelfth end E12. For example, the second protective layer 320 may include: a ninth end E9 spaced apart from the first end E1 of the substrate 100 and configured to face each other directly; a tenth end E10 spaced apart from the second end E2 of the substrate 100 and configured to face each other directly; an eleventh end E11 spaced apart from the third end E3 of the substrate 100 and configured to face each other directly; and a twelfth end E12 spaced apart from the fourth end E4 of the substrate 100 and configured to face each other directly.

[0185] Furthermore, the ninth end E9, the tenth end E10, the eleventh end E11, and the twelfth end E12 can be configured to be spaced apart from the ends of the first protective layer 310.

[0186] Furthermore, the ninth end E9 and the tenth end E10 can be configured to face each other, and the eleventh end E11 and the twelfth end E12 can be connected to the ninth end E9 and the tenth end E10 respectively and configured to face each other.

[0187] That is, the ninth end E9 and the tenth end E10 can be arranged to face each other in the first direction 1D, and the eleventh end E11 and the twelfth end E12 can be arranged to face each other in the second direction 2D.

[0188] The fifth outer pattern OP5 and the sixth outer pattern OP6 can be arranged to face each other in the second direction 2D. Furthermore, the seventh outer pattern OP7 and the eighth outer pattern OP8 can be arranged to face each other in the second direction 2D.

[0189] The fifth outer pattern OP5 and the seventh outer pattern OP7 can be disposed between the first outer pattern OP1 and the third outer pattern OP3 along the first direction. That is, the fifth outer pattern OP5 and the seventh outer pattern OP7 can be disposed spaced apart from each other in the first direction 1D.

[0190] The sixth outer pattern OP6 and the eighth outer pattern OP8 can be disposed between the second outer pattern OP2 and the fourth outer pattern OP4 along the first direction. That is, the sixth outer pattern OP6 and the eighth outer pattern OP8 can be disposed spaced apart from each other in the first direction 1D.

[0191] At least one of the fifth outer pattern OP5, the sixth outer pattern OP6, the seventh outer pattern OP7 and the eighth outer pattern OP8 can be integrally formed with at least one of the first outer pattern OP1, the second outer pattern OP2, the third outer pattern OP3 and the fourth outer pattern OP4.

[0192] Optionally, at least one of the fifth outer pattern OP5, the sixth outer pattern OP6, the seventh outer pattern OP7 and the eighth outer pattern OP8 may be formed to be separate from at least one of the first outer pattern OP1, the second outer pattern OP2, the third outer pattern OP3 and the fourth outer pattern OP4.

[0193] The fifth outer pattern OP5 may include the ninth pattern part P9 and the tenth pattern part P10, the sixth outer pattern OP6 may include the eleventh pattern part P11 and the twelfth pattern part P12, the seventh outer pattern OP7 may include the thirteenth pattern part P13 and the fourteenth pattern part P14, and the eighth outer pattern OP8 may include the fifteenth pattern part P15 and the sixteenth pattern part P16.

[0194] The shape and size (width and length) of the ninth pattern part P9, the tenth pattern part P10, the eleventh pattern part P11, the twelfth pattern part P12, the thirteenth pattern part P13, the fourteenth pattern part P14, the fifteenth pattern part P15 and the sixteenth pattern part P16 can be formed to be the same as or similar to the shape and size of the first pattern part P1 to the eighth pattern part P8 mentioned above.

[0195] That is, the ninth pattern part P9, the tenth pattern part P10, the eleventh pattern part P11, the twelfth pattern part P12, the thirteenth pattern part P13, the fourteenth pattern part P14, the fifteenth pattern part P15, and the sixteenth pattern part P16 can be formed into at least one shape of relief part and engraved part, and can extend in the direction of the third end E3 and the fourth end E4 of the substrate.

[0196] Furthermore, the ninth pattern section P9 and the tenth pattern section P10, the eleventh pattern section P11 and the twelfth pattern section P12, the thirteenth pattern section P13 and the fourteenth pattern section P14, the fifteenth pattern section P15 and the sixteenth pattern section P16 can be arranged to be spaced apart from each other in a first direction, and each space can be spaced apart by the same or similar space as the spaced spaced from the first pattern section P1 to the eighth pattern section P8 described above.

[0197] Specifically, the ninth pattern portion P9 and the tenth pattern portion P10 can be arranged to be spaced apart from each other in the first direction 1D. Furthermore, the ninth end portion E9 of the second protective layer 320 can pass between the ninth pattern portion P9 and the tenth pattern portion P10. That is, the ninth end portion E9 of the second protective layer 320 can be disposed between the ninth pattern portion P9 and the tenth pattern portion P10.

[0198] Furthermore, the eleventh pattern portion P11 and the twelfth pattern portion P12 can be arranged to be spaced apart from each other in the first direction 1D. Additionally, the ninth end portion E9 of the second protective layer 320 can pass between the eleventh pattern portion P11 and the twelfth pattern portion P12. That is, the ninth end portion E9 of the second protective layer 320 can be disposed between the eleventh pattern portion P11 and the twelfth pattern portion P12.

[0199] In other words, the ninth end E9 of the second protective layer 320 can be disposed between the ninth pattern portion P9 and the tenth pattern portion P10, and between the eleventh pattern portion P11 and the twelfth pattern portion P12.

[0200] Furthermore, the thirteenth pattern portion P13 and the fourteenth pattern portion P14 can be spaced apart from each other in the first direction 1D. Additionally, the tenth end portion E10 of the second protective layer 320 can pass between the thirteenth pattern portion P13 and the fourteenth pattern portion P14. That is, the tenth end portion E10 of the second protective layer 320 can be disposed between the thirteenth pattern portion P13 and the fourteenth pattern portion P14.

[0201] Furthermore, the fifteenth pattern portion P15 and the sixteenth pattern portion P16 can be spaced apart from each other in the first direction 1D. Additionally, the tenth end portion E10 of the second protective layer 320 can pass between the fifteenth pattern portion P15 and the sixteenth pattern portion P16. That is, the tenth end portion E10 of the second protective layer 320 can be disposed between the fifteenth pattern portion P15 and the sixteenth pattern portion P16.

[0202] In other words, the tenth end E10 of the second protective layer 320 can be disposed between the thirteenth pattern portion P13 and the fourteenth pattern portion P14, and between the fifteenth pattern portion P15 and the sixteenth pattern portion P16.

[0203] The flexible printed circuit board according to the second embodiment may further include a second protective layer disposed on the first protective layer. That is, two protective layers may be disposed in one region of the flexible printed circuit board. In other words, two protective layers may be disposed in a curved region of the flexible printed circuit board.

[0204] Therefore, it can prevent cracks from appearing on the flexible printed circuit board due to the stress generated when the flexible printed circuit board is bent.

[0205] Furthermore, the flexible printed circuit board may include multiple external patterns, and each external pattern may include multiple pattern portions spaced apart from each other.

[0206] Therefore, when the second protective layer 320 is provided, the position of the second protective layer in the first direction can be easily controlled.

[0207] In other words, the position of the second protective layer can be adjusted so that the end of the second protective layer 320 is positioned between the patterned portions. Therefore, the position of the second protective layer can be easily controlled to the position where it is to be applied through the patterned portions.

[0208] Therefore, it is possible to prevent the need for additional, unnecessary protective layers due to placing the second protective layer outside the intended location. Furthermore, it is possible to prevent the flexible printed circuit board from deforming due to stress generated in the bending area if the second protective layer is placed below the intended location.

[0209] Therefore, the flexible printed circuit board according to the first embodiment can easily control the position of the protective layer by means of a plurality of patterned portions formed on the outer pattern. Thus, the flexible printed circuit board according to the embodiment can improve bonding characteristics and has improved reliability.

[0210] Meanwhile, the above description has already described a flexible printed circuit board with a single metal COF having the first and second circuit patterns disposed on only one surface of the substrate, but the embodiments are not limited thereto.

[0211] In detail, the first circuit pattern and the second circuit pattern can be disposed on one surface of the substrate and another surface opposite to the one surface.

[0212] In other words, the flexible printed circuit board according to the embodiment can be a bimetallic COF in which circuit patterns are disposed on both surfaces of the substrate 100.

[0213] For example, the first circuit pattern 210 and the second circuit pattern 220 can be connected to the chip in the chip mounting area CA on the first surface of the substrate 100. Furthermore, the first circuit pattern 210 and the second circuit pattern 220 can be connected to an external printed circuit board and a display panel on the second surface of the substrate 100.

[0214] Furthermore, a plurality of through holes formed through the first and second surfaces can be formed in the substrate 100, and the circuit patterns disposed on the first and second surfaces of the substrate can be electrically connected through the through holes.

[0215] That is, the first circuit pattern 210 and the second circuit pattern 220 can be disposed on two surfaces of the substrate 100 to separate the surfaces on which the chip, the printed circuit board and the display panel are connected.

[0216] When the circuit pattern is disposed on both surfaces of the substrate 100, the protective layer disposed on the circuit pattern can also be disposed on both surfaces of the substrate 100.

[0217] Therefore, when the flexible printed circuit board is a bimetallic COF, multiple external patterns including at least two pattern portions can be provided on the first surface of the substrate, and multiple external patterns including at least two pattern portions can also be provided on the second surface of the substrate on the first surface of the substrate.

[0218] Furthermore, when two protective layers are disposed on either the first surface or the second surface, a plurality of external patterns, including at least two pattern portions, may be further disposed on the surface on which the double protective layers are disposed.

[0219] Therefore, even when the flexible printed circuit board is a bimetallic COF, the positions of the protective layers disposed on one surface and the other surface of the substrate can be appropriately set at the locations to be implemented.

[0220] Figure 10 This is a top view of the COF module according to an embodiment.

[0221] refer to Figure 10 According to the embodiment, the COF module may include the flexible printed circuit board described above and the chip C disposed in the chip mounting area CA of the flexible printed circuit board 1000.

[0222] In addition, the flexible printed circuit board 1000 may include the aforementioned protective layer 300.

[0223] Simultaneously, the COF module can be manufactured by cutting the second region 2A of the flexible printed circuit board 1000 and then mounting the chip C. Specifically, in the cutting... Figure 1 After the boundary line CL between the first region 1A and the second region 2A, a COF module 2000 can be manufactured, in which a driver chip electrically connected to the first circuit pattern and the second circuit pattern and disposed in the chip mounting area of ​​the flexible printed circuit board is installed.

[0224] For example, after testing the driving characteristics of a flexible printed circuit board by wiring and pads set outside the cut line CL of the flexible printed circuit board, the flexible printed circuit board can be cut along the cut line CL.

[0225] The COF module can be located between the display panel and the substrate to connect electrical signals.

[0226] In other words, the pad portions of the first and second circuit patterns exposed without the protective layer 300 can be connected to the display panel and the printed circuit board, and the third circuit pattern in the chip mounting area can be connected to the chip.

[0227] refer to Figure 11 One end of the COF module 2000, which includes a flexible printed circuit board according to the embodiment, can be connected to the display panel 3000, and the other end opposite to the one end can be connected to the printed circuit board 4000.

[0228] For example, one end of the COF module 2000, which includes a flexible printed circuit board according to an embodiment, can be electrically connected by contacting a display panel 3000, and the other end opposite to that one end can be electrically connected by contacting a printed circuit board 4000. Here, contact can refer to direct contact. Alternatively, it can refer to contact with an anisotropic conductive film (ACF) inserted therein.

[0229] As an example, an ACF (Acoustic Coating Fluid) can be disposed between the COF module 2000 and the printed circuit board 4000. The COF module 2000 and the printed circuit board 4000 can be electrically connected while being adhered by the ACF. The ACF can be a resin in which conductive particles are dispersed. Therefore, electrical signals connected through the printed circuit board 4000 can be transmitted to the COF module 2000 through the conductive particles contained in the ACF.

[0230] Because the COF module 2000 includes a flexible substrate, it can have a rigid or curved shape between the display panel 3000 and the printed circuit board 4000.

[0231] The COF module 2000 can connect the display panel 3000 and the printed circuit board 4000, which are arranged opposite each other, in a curved shape, thereby reducing the thickness of the electronic device and increasing design flexibility. Furthermore, since the COF module 2000, including the flexible substrate, will not break even in a curved shape, the reliability of electronic devices including the COF module can be improved.

[0232] Because COF modules are flexible, they can be used in a variety of electronic devices.

[0233] For example, refer to Figure 12 The COF module can be included in a flexible touch window. Therefore, a touch device including a COF module can be a flexible touch device. Thus, the user can bend or fold it by hand. Such a flexible touch window can be applied to wearable touch devices, etc.

[0234] refer to Figure 13COF modules can be included in various wearable touch devices that incorporate curved displays. Therefore, the thickness or weight of electronic devices including COF modules can be reduced.

[0235] refer to Figure 14 COF modules can be used in various electronic devices with displays, such as TVs, monitors, and laptops. In this case, COF modules can be used in electronic devices with curved display sections.

[0236] However, the embodiments are not limited to this. Of course, such COF flexible printed circuit boards and COF modules obtained by processing them can be used in a variety of electronic devices.

[0237] 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 can combine or modify the features, structures, and effects described in each embodiment for other embodiments. Therefore, anything related to such combinations and modifications should be understood to be included within the scope of this invention.

[0238] Furthermore, the above description primarily focuses on embodiments, but these embodiments are merely examples and are not intended to limit the invention. Those skilled in the art will understand that various changes and applications not mentioned above can be made without departing from the basic characteristics of the embodiments. For example, each component specifically represented in the embodiments can be modified. Moreover, it should be understood that differences associated with such changes and applications are included within the scope of the invention as defined by the appended claims.

Claims

1. A flexible printed circuit board, comprising: substrate; A circuit pattern disposed on the substrate; as well as A protective layer is applied to the circuit pattern. The circuit pattern includes a first circuit pattern and a second circuit pattern that are connected to the chip in the chip mounting area. The substrate is defined with a first direction and a second direction, the first direction being the direction in which the circuit pattern extends, and the second direction being perpendicular to the first direction. The substrate includes a first end and a second end facing each other in the first direction, and a third end and a fourth end facing each other in the second direction. The protective layer includes a fifth end and a sixth end spaced apart from the ends of the substrate and facing the first direction, and a seventh end and an eighth end spaced apart from the ends of the substrate and facing the second direction. The flexible printed circuit board includes an external pattern disposed adjacent to the third end and the fourth end on the substrate. The external pattern includes: A first outer pattern and a second outer pattern, wherein the first outer pattern and the second outer pattern are adjacent to the pad portion of the first circuit pattern and face the second direction; and The third and fourth outer patterns are adjacent to the pad portion of the second circuit pattern and face the second direction. The first outer pattern includes a first pattern portion and a second pattern portion spaced apart from each other. The second outer pattern includes a third pattern portion and a fourth pattern portion spaced apart from each other. The third outer pattern includes a fifth pattern portion and a sixth pattern portion spaced apart from each other. The fourth outer pattern includes a seventh pattern portion and an eighth pattern portion spaced apart from each other, and The fifth end of the protective layer is disposed between the first pattern portion and the second pattern portion, and between the third pattern portion and the fourth pattern portion.

2. The flexible printed circuit board according to claim 1, wherein, The sixth end of the protective layer is disposed between the fifth pattern portion and the sixth pattern portion, and between the seventh pattern portion and the eighth pattern portion.

3. The flexible printed circuit board according to claim 1, wherein, The first pattern portion and the second pattern portion are spaced apart in the first direction. The third pattern portion and the fourth pattern portion are spaced apart in the first direction. The fifth pattern portion and the sixth pattern portion are spaced apart in the first direction, and The seventh pattern portion and the eighth pattern portion are spaced apart in the first direction.

4. The flexible printed circuit board according to claim 1, wherein, The first end, the second end, the third end, and the fourth end extend along the cut line of the substrate.

5. The flexible printed circuit board according to claim 1, wherein, At least one of the intervals between the first pattern portion and the second pattern portion, the intervals between the third pattern portion and the fourth pattern portion, the intervals between the fifth pattern portion and the sixth pattern portion, and the intervals between the seventh pattern portion and the eighth pattern portion is 100 μm to 300 μm.

6. The flexible printed circuit board according to claim 1, wherein, The width of at least one of the first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion is 20 μm to 50 μm.

7. The flexible printed circuit board according to claim 1, wherein, The length of at least one of the first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion is 20 μm to 50 μm.

8. The flexible printed circuit board according to claim 1, wherein, The first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion are configured as relief portions or engraved portions.

9. The flexible printed circuit board according to claim 8, wherein, The first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion are configured to resemble the shape of the relief portion, and The first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion extend in the direction of at least one of the third end and the fourth end of the substrate.

10. The flexible printed circuit board according to claim 1, wherein, The first pattern portion, the second pattern portion, the third pattern portion, the fourth pattern portion, the fifth pattern portion, the sixth pattern portion, the seventh pattern portion, and the eighth pattern portion are spaced 20 μm apart from the circuit pattern adjacent to the external pattern.

11. The flexible printed circuit board according to claim 1, further comprising a second protective layer on the protective layer, in, The second protective layer includes: a ninth end and a tenth end spaced apart from the ends of the substrate and facing the first direction; and an eleventh end and a twelfth end spaced apart from the ends of the substrate and facing the second direction. The outer pattern includes: a fifth outer pattern and a sixth outer pattern facing the second direction; and a seventh outer pattern and an eighth outer pattern facing the second direction. The fifth outer pattern includes a ninth pattern portion and a tenth pattern portion that are spaced apart from each other. The sixth outer pattern includes an eleventh pattern portion and a twelfth pattern portion that are spaced apart from each other. The seventh outer pattern includes a thirteenth pattern portion and a fourteenth pattern portion that are spaced apart from each other. The eighth outer pattern includes a fifteenth pattern portion and a sixteenth pattern portion spaced apart from each other, and The ninth end of the second protective layer is disposed between the ninth pattern portion and the tenth pattern portion, and between the eleventh pattern portion and the twelfth pattern portion.

12. The flexible printed circuit board according to claim 11, wherein, The tenth end of the second protective layer is disposed between the thirteenth and fourteenth pattern portions and between the fifteenth and sixteenth pattern portions.

13. The flexible printed circuit board according to claim 11, wherein, The ninth pattern portion and the tenth pattern portion are spaced apart in the first direction. The eleventh pattern portion and the twelfth pattern portion are spaced apart in the first direction. The thirteenth pattern portion and the fourteenth pattern portion are spaced apart in the first direction, and The fifteenth pattern portion and the sixteenth pattern portion are spaced apart in the first direction.

14. The flexible printed circuit board according to claim 11, wherein, The ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, and sixteenth pattern sections are designed to resemble relief or engraving sections.

15. The flexible printed circuit board according to claim 14, wherein, The ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, and sixteenth pattern portions are designed in the shape of relief portions, and The ninth pattern portion, the tenth pattern portion, the eleventh pattern portion, the twelfth pattern portion, the thirteenth pattern portion, the fourteenth pattern portion, the fifteenth pattern portion, and the sixteenth pattern portion extend in the direction of at least one of the third end and the fourth end.

16. The flexible printed circuit board according to claim 1, wherein, The first circuit pattern and the second circuit pattern are disposed on the same surface of the substrate.

17. The flexible printed circuit board according to claim 1, wherein, The first circuit pattern and the second circuit pattern are disposed on one surface of the substrate and on another surface opposite to the one surface.

18. A chip-on-film module, comprising: The flexible printed circuit board according to claim 1; as well as The chip is disposed in the chip mounting area.

19. The on-film chip module according to claim 18, wherein, The external pattern is not connected to the chip.

20. An electronic device, comprising: The chip-on-film module according to claim 19; A printed circuit board connected to the first circuit pattern; as well as The display panel is connected to the second circuit pattern.

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