# US 2019/0174620 A1 · Flexible circuit board, optical transceiver assembly, and optical module > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0174620 A1 - Document ID: US20190174620A1 - Status: Published application - Kind: A1 - Application number: 16/190,400 - Filed: 2018-11-14 - Published: 2019-06-06 - Earliest claimed: 2017-11-17 - Assignees: InnoLight Technology (Suzhou) Ltd. - Applicants: InnoLight Technology (Suzhou) LTD. - Inventors: Xigui FANG; Qin CHEN; Yunfei HOU; Jie ZHOU - Web page: https://patentgrep.com/patent/US20190174620A1 ## CPC - H05K 1/028: {Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence)} - G02B 6/42: Coupling light guides with opto-electronic elements - G02B 6/4281: {the printed circuit boards being flexible (in general H05K1/147)} - H04B 10/40: Transceivers - H05K 1/0353: {consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement} - H05K 1/111: {Pads for surface mounting, e.g. lay-out} - H05K 1/113: {Via provided in pad; Pad over filled via} - H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions} - H05K 1/144: {Stacked arrangements of planar printed circuit boards} - H05K 1/181: associated with surface mounted components - H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)} - H05K 1/189: characterised by the use of flexible or folded printed circuits - H05K 2201/0141: Liquid crystal polymer [LCP] - H05K 2201/015: Fluoropolymer, e.g. polytetrafluoroethylene [PTFE] - H05K 2201/0154: Polyimide - H05K 2201/10121: Optical component, e.g. opto-electronic component - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04B: TRANSMISSION ## Abstract A flexible circuit board, and an optical transceiver assembly and an optical module that have such flexible circuit board. The flexible circuit board includes a substrate body, a transmission metal layer formed on at least one surface of the substrate body, a strengthening layer formed on the transmission metal layer, and a surface metal layer formed on a portion of an outer surface of the strengthening layer. The surface metal layer constitutes a securing portion for securing and connecting to an external element. A portion of the flexible circuit board that is not covered by the surface metal layer constitutes a connecting portion that connects to the securing portion. The surface metal layer is electrically connected to the transmission metal layer. ## Claims ### Claim 1 A flexible circuit board, comprising: a substrate body; a transmission metal layer formed on at least one surface of the substrate body; a strengthening layer formed on the transmission metal layer; and a surface metal layer formed on a portion of an outer surface of the strengthening layer, wherein the surface metal layer of the flexible circuit board constitutes a securing portion for securing and connecting to an external element, a portion of the flexible circuit board that is not covered by the surface metal layer constitutes a connecting portion that connects to the securing portion; and the surface metal layer is electrically connected to the transmission metal layer. ### Claim 2 (depends on 1) The flexible circuit board of claim 1, wherein a solder pad is formed at the securing portion for securing and connecting the flexible circuit board to the external element. ### Claim 3 (depends on 1) The flexible circuit board of claim 1, wherein the flexible circuit board further comprises a pore structure and the surface metal layer is electrically connected to the transmission metal layer through the pore structure. ### Claim 4 (depends on 3) The flexible circuit board of claim 3, wherein the pore structure is formed in a middle portion of the securing portion. ### Claim 5 (depends on 1) The flexible circuit board of claim 1, wherein the material of the strengthening layer is a liquid crystal polymer, a polyimide, or Teflon®. ### Claim 6 (depends on 1) The flexible circuit board of claim 1, wherein the flexible circuit board further comprises one or a plurality of the securing portions. ### Claim 7 (depends on 1) The flexible circuit board of claim 1, wherein a pattern of the surface metal layer is formed by etching. ### Claim 8 (depends on 1) The flexible circuit board of claim 1, wherein the substrate body is a multilayer board structure. ### Claim 9 (depends on 1) An optical transceiver assembly, comprising: at least one of an optical transmitting element or an optical receiving element; and the flexible circuit board of claim 1, wherein the flexible circuit board is secured and connected to the at least one of the optical transmitting element or the optical receiving element through the securing portion. ### Claim 10 (depends on 1) An optical module, comprising: at least one of an optical transmitting element or an optical receiving element; a rigid circuit board; and the flexible circuit board of claim 1, wherein the flexible circuit board is connected to the at least one of the optical transmitting element or the optical receiving element and the rigid circuit board through the securing portion.