# US 10,120,411 B2 · Systems with low-friction matte flexible printed circuits > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,411 B2 - Document ID: US10120411B2 - Status: Granted - Kind: B2 - Application number: 15/243,370 - Filed: 2016-08-22 - Published: 2018-02-22 - Granted: 2018-11-06 - Earliest claimed: 2016-08-22 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Bryan W. Posner; Adam T. Garelli - Web page: https://patentgrep.com/patent/US10120411B2 ## CPC - G06F 1/1616: {with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position} - G06F 1/1681: {Details related solely to hinges (hinge details related to the transmission of signals or power are classified in G06F1/1683)} - G06F 1/1683: {for the transmission of signal or power between the different housings, e.g. details of wired or wireless communication, passage of cabling} - H05K 1/0281: {Reinforcement details thereof} - H05K 3/285: {Permanent coating compositions} - H05K 2201/015: Fluoropolymer, e.g. polytetrafluoroethylene [PTFE] - H05K 2203/1173: Differences in wettability, e.g. hydrophilic or hydrophobic areas - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract An electronic device may include flexible printed circuits. A flexible printed circuit may have metal traces supported by a polymer substrate. The flexible printed circuit may extend between an upper laptop computer housing and a lower laptop computer housing or other structures that move relative to each other in an electronic device. The flexible printed circuit may have a low-friction coating and a matte finish. The flexible printed circuit may have a fluoropolymer coating on the polymer substrate, a fluoropolymer coating on a matte coating on the polymer substrate, a fluoropolymer coating that includes a matting agent on the polymer substrate, a fluoropolymer layer or other polymer layer that is attached to the substrate with a layer of adhesive, a textured surface layer, and/or other structures that help provide the flexible printed circuit with desired physical properties and a desired appearance. ## Claims ### Claim 1 A flexible printed circuit, comprising: a flexible polymer substrate; metal traces embedded in the flexible polymer substrate; and a hydrophobic layer on the flexible polymer substrate, wherein the hydrophobic layer comprises a fluoropolymer layer having a matting agent and exhibiting a gloss value of less than 2 gloss units at 60° . ### Claim 2 (depends on 1) The flexible printed circuit defined in claim 1 wherein the fluoropolymer layer is attached to the flexible polymer substrate with a layer of adhesive. ### Claim 3 (depends on 2) The flexible printed circuit defined in claim 2 wherein: the flexible polymer substrate comprises polyimide and the fluoropolymer comprises polytetrafluoroethylene. ### Claim 4 (depends on 2) The flexible printed circuit defined in claim 2 wherein the fluoropolymer layer comprises a black textured polytetrafluoroethylene layer. ### Claim 5 (depends on 1) The flexible printed circuit defined in claim 1 wherein the fluoropolymer layer has a water contact angle of at least 105°. ### Claim 6 (depends on 5) The flexible printed circuit defined in claim 5 further comprising a matte polymer layer interposed between the flexible polymer substrate and the fluoropolymer layer, wherein the fluoropolymer layer on the flexible polymer substrate with the matte polymer layer interposed between the flexible polymer substrate and the fluoropolymer layer has a gloss value of less than 20 gloss units at 60°. ### Claim 7 (depends on 1) The flexible printed circuit defined in claim 1 wherein the fluoropolymer layer is a black fluoropolymer layer having a water contact angle of at least 110°. ### Claim 8 (depends on 7) The flexible printed circuit defined in claim 7 wherein the black fluoropolymer layer includes a matting agent, wherein the black fluoropolymer layer has a gloss value of less than 2 gloss units at 60°, and wherein the black fluoropolymer layer has a water contact angle of at least 150°. ### Claim 9 A portable computer, comprising: a metal housing having an upper housing portion that contains a display and having a lower housing portion; first and second hinges that connect the upper housing portion to the lower housing portion, wherein the upper and lower housing portions are rotatable with respect to each other; circuitry in the lower housing portion; and a hydrophobic flexible printed circuit that is coupled between the circuitry in the lower housing portion and the display in the upper housing portion. ### Claim 10 (depends on 9) The portable computer defined in claim 9 wherein the hydrophobic flexible printed circuit includes a polymer substrate and a hydrophobic layer on the polymer substrate. ### Claim 11 (depends on 10) The portable computer defined in claim 10 wherein the hydrophobic layer comprises a fluoropolymer coating on the polymer substrate. ### Claim 12 (depends on 11) The portable computer defined in claim 11 wherein the hydrophobic layer is characterized by a water contact angle of at least 130°. ### Claim 13 (depends on 10) The portable computer defined in claim 10 wherein the hydrophobic layer comprises a fluoropolymer layer attached to the polymer substrate by a layer of adhesive. ### Claim 14 (depends on 13) The portable computer defined in claim 13 wherein the fluoropolymer layer comprises a layer of textured black polytetrafluoroethylene. ### Claim 15 (depends on 10) The portable computer defined in claim 10 wherein the hydrophobic layer comprises a fluoropolymer layer and wherein the flexible printed circuit further comprises a matte coating layer between the polymer substrate and the fluoropolymer layer. ### Claim 16 (depends on 10) The portable computer defined in claim 10 wherein the hydrophobic layer comprises a fluoropolymer coating mixed with a matting agent and wherein the fluoropolymer coating mixed with the matting agent has a gloss value of less than 10 gloss units at 85°. ### Claim 17 A flexible printed circuit, comprising: a flexible polymer substrate containing metal traces; and a flexible fluoropolymer coating on the flexible polymer substrate, wherein the flexible fluoropolymer coating has a water contact angle of at least 130°, wherein the flexible fluoropolymer coating comprises a matting agent, and wherein the flexible fluoropolymer coating exhibits a gloss at 60° of less than 2 gloss units. ### Claim 18 (depends on 17) The flexible printed circuit defined in claim 17 wherein the flexible fluoropolymer coating comprises a black fluoropolymer coating.