# US 10,321,562 B2 · Flexible circuit board, COF module and electronic device comprising the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,562 B2 - Document ID: US10321562B2 - Status: Granted - Kind: B2 - Application number: 15/657,296 - Filed: 2017-07-24 - Published: 2018-01-25 - Granted: 2019-06-11 - Earliest claimed: 2016-07-22 - Assignees: LG Innotek Co., Ltd. - Applicants: LG Innotek Co., Ltd. - Inventors: Jun Young Lim; Woong Sik Kim; Hyung Kyu Yoon; Min Hwan Kim - Web page: https://patentgrep.com/patent/US10321562B2 ## CPC - H05K 1/0281: {Reinforcement details thereof} - H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion} - H05K 1/144: {Stacked arrangements of planar printed circuit boards} - H05K 3/18: using precipitation techniques to apply the conductive material - H05K 3/28: Applying non-metallic protective coatings {(H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673)} - H10W 70/04: of leadframes - H10W 70/688: {Flexible insulating substrates} - H10W 99/00: Subject matter not provided for in other groups of this subclass - H05K 1/189: characterised by the use of flexible or folded printed circuits - H05K 2201/055: Folded back on itself - H05K 2201/10128: Display - H10W 70/098: {Applying pastes or inks, e.g. screen printing (H10W70/095 takes precedence)} - H10W 70/635: {Through-vias} - H10W 70/682: {comprising holes having chips therein} - H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL} - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A flexible circuit board and an electronic device including a flexible circuit board are provided. The flexible circuit board may include a substrate having a bending area and a non-bending area, a wiring pattern layer provided on the bending area and the non-bending area, a plating layer provided on the wiring pattern layer and including an open area in an area corresponding to the bending area, and a protective layer that directly contacts one surface of the wiring pattern layer exposed at the open area and a side surface of the plating layer. The protective layer may have a larger thickness than a thickness of the plating layer. ## Claims ### Claim 1 A flexible circuit board comprising: a substrate having a bending area and a non-bending area; a first wiring pattern layer provided on the bending area and the non-bending area on a first surface of the substrate; a first plating layer provided on the first wiring pattern layer, and including a first open area in an area corresponding to the bending area; a second plating layer provided on the first plating layer; a first protective layer that directly contacts one surface of the first wiring pattern layer exposed at the first open area, a side surface of the first plating layer, and a side surface of the second plating layer; a second wiring pattern layer provided on the bending area and the non-bending area on a second surface opposite to the first surface of the substrate; a third plating layer provided on the second wiring pattern layer; a fourth plating layer provided on the third plating layer; and a second protective layer provided on an area corresponding to the bending area on the second surface of the substrate, wherein the first protective layer is provided higher than an upper surface of the second plating layer, a width of a second open area of the second plating layer is larger than a width of the first open area of the first plating layer, and an upper surface of the first plating layer exposed in the second open area is in direct contact with the first protective layer. ### Claim 2 (depends on 1) The flexible circuit board of claim 1, wherein the first protective layer is provided on at least a part of the bending area. ### Claim 3 (depends on 1) The flexible circuit board of claim 1, wherein a width of a contact area between the first protective layer and the first wiring pattern layer is equal to a width of a contact area between the second protective layer and the second wiring pattern layer. ### Claim 4 (depends on 1) The flexible circuit board of claim 1, wherein at least one protective layer of the first protective layer and the second protective layer has a thickness of 1 to 20 μm. ### Claim 5 (depends on 1) The flexible circuit board of claim 1, wherein the third plating layer and the fourth plating layer include an open area in an area corresponding to the bending area, and the second protective layer contacts one surface of the second wiring pattern layer. ### Claim 6 (depends on 5) The flexible circuit board of claim 5, wherein an open area on the first surface of the substrate vertically overlaps with an open area on the second surface of the substrate. ### Claim 7 (depends on 1) The flexible circuit board of claim 1, wherein the second protective layer is in contact with one surface of the fourth plating layer. ### Claim 8 (depends on 1) A flexible circuit board chip package comprising the flexible circuit board of claim 1, wherein the plating layer is connected to a chip in an area where the protective layer is not provided. ### Claim 9 (depends on 1) An electronic device comprising the flexible circuit board of claim 1, further comprising: a display panel connected to a first end of the flexible circuit board; and a printed circuit board connected to a second end opposite to the first end of the flexible circuit board. ### Claim 10 (depends on 1) The flexible circuit board of claim 1, wherein a cross-sectional shape of at least one protective layer of the first protective layer and the second protective layer is T-shaped. ### Claim 11 (depends on 1) The flexible circuit board of claim 1, wherein the first protective layer has a shape different from a shape of the second protective layer. ### Claim 12 (depends on 1) The flexible circuit board of claim 1, wherein one protective layer of the first protective layer and the second protective layer have an upper surface and a lower surface, the upper surfaces having widths different from widths of the lower surfaces. ### Claim 13 (depends on 12) The flexible circuit board of claim 12, wherein a width of the upper surface of the one protective layer of the first protective layer is larger than the width of the lower surface of the one protective layer of the first protective layer. ### Claim 14 (depends on 1) The flexible circuit board of claim 1, wherein a thickness of the first protective layer is larger than a thickness of the second protective layer. ### Claim 15 (depends on 1) The flexible circuit board of claim 1, wherein an outer side of a first end of the bending area includes a first overlapping region in which the first plating layer and the first protective layer are in contact with each other, and an outer side of a second end of the bending area includes a second overlapping region in which the first plating layer and the first protective layer are in contact with each other. ### Claim 16 (depends on 15) The flexible circuit board of claim 15, wherein a width of the first overlapping region corresponds to or is different from a width of the second overlapping region. ### Claim 17 A flexible circuit board, comprising: a substrate including a bending area and a non-bending area; a first wiring pattern layer provided on the bending area and the non-bending area on a first surface of the substrate; a first plating layer provided on the first wiring pattern layer, and including a first open area in an area corresponding to the bending area; a second plating layer provided on the first plating layer; a first protective layer that directly contacts one surface of the first wiring pattern layer exposed at the first open area, a side surface of the first plating layer, and a side surface of the second plating layer; a second wiring pattern layer provided on the bending area and the non-bending area on a second surface opposite to the first surface of the substrate; a third plating layer provided on the second wiring pattern layer; a fourth plating layer provided on the third plating layer; and a second protective layer provided on an area corresponding to the bending area on the second surface of the substrate, wherein the first protective layer is provided higher than an upper surface of the second plating layer, the first protective layer includes an upper first protective layer and a lower first protective layer, and the upper first protective layer is in direct contact with the upper surfaces of the lower first protective layer and the second plating layer. ### Claim 18 (depends on 17) The flexible circuit board of claim 17, wherein the upper first protective layer includes an overlapping region in contact with the second plating layer, and a width of the overlapping region is larger than a sum of thicknesses of the first plating layer and the second plating layer. ### Claim 19 (depends on 17) The flexible circuit board of claim 17, wherein a width of a second open area of the second plating layer corresponds to a width of the first open area of the first plating layer. ### Claim 20 A flexible circuit board comprising: a substrate having a bending area and a non-bending area; a first wiring pattern layer provided on the bending area and the non-bending area on a first surface of the substrate; a first plating layer provided on the first wiring pattern layer, and including a first open area in an area corresponding to the bending area; a second plating layer provided on the first plating layer; a first protective layer that directly contacts one surface of the first wiring pattern layer exposed at the first open area, a side surface of the first plating layer, and a side surface of the second plating layer; a second wiring pattern layer provided on the bending area and the non-bending area on a second surface opposite to the first surface of the substrate; a third plating layer provided on the second wiring pattern layer; a fourth plating layer provided on the third plating layer; and a second protective layer provided on an area corresponding to the bending area on the second surface of the substrate, wherein the first protective layer is provided higher than an upper surface of the second plating layer, the second protective layer includes an upper second protective layer and a lower second protective layer, and the upper second protective layer directly contacts the upper surfaces of the lower second protective layer and the fourth plating layer.