# US 11,029,460 B2 · Waveguide and method of identifying a waveguide that is too severely curved > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,460 B2 - Document ID: US11029460B2 - Status: Granted - Kind: B2 - Application number: 16/489,295 - Filed: 2018-02-23 - Published: 2020-02-27 - Granted: 2021-06-08 - Earliest claimed: 2017-03-06 - Assignees: LEONI Kabel GmbH - Applicants: LEONI KABEL GmbH - Inventors: Robert Hanf - Web page: https://patentgrep.com/patent/US11029460B2 ## CPC - G02B 6/0003: {the light guides being doped with fluorescent agents} - G01M 11/088: {of optical fibres; Mechanical features associated with the optical testing of optical fibres} - G02B 6/0008: {the light being emitted at the end of the fibre} - G02B 6/02395: {Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR ## Abstract A waveguide, in particular an optical fiber, is coated and is of flexible configuration so that the waveguide can be laid in an adaptable manner, wherein the coating includes a light-frequency-converting substance so that in the event of UV light or IR light being coupled into the waveguide and an overbent waveguide, visible light escapes from the waveguide at a bend point. ## Claims ### Claim 1 A waveguide, comprising: a core, a cladding, and a coating, wherein the coating is immediately adjacent to the core, wherein the waveguide is of flexible configuration so that the waveguide can be laid in an adaptable manner, wherein the coating comprises a light-frequency-converting substance and the light-frequency-converting substance converts UV or IR light into visible light, so that in the event of UV light or IR light being coupled into the waveguide and an overbent waveguide at a bend point, visible light escapes from the waveguide at the bend point, and wherein the coating is disposed between the core and the cladding. ### Claim 2 (depends on 1) The waveguide according to claim 1, wherein the light-frequency-converting substance has a concentration of less than 5.0 wt. % and more than 0.1 wt. %, based on a total mass of the coating. ### Claim 3 (depends on 1) The waveguide according to claim 1 wherein the light-frequency-converting substance is selected such that the light-frequency-converting substance generates a low-frequency light from a higher-frequency light. ### Claim 4 (depends on 1) The waveguide according to claim 1 wherein the light-frequency-converting substance is selected from the group consisting of a coumarin dye, a cyanine dye, a flavine dye, a luciferin dye, a phycobilin dye, a rhodamine dye, a safranin dye and a combination of two or more of the aforementioned dyes. ### Claim 5 (depends on 1) The waveguide according to claim 1 wherein the light-frequency-converting substance is selected such that the light-frequency-converting substance generates a higher-frequency light from a low-frequency light. ### Claim 6 (depends on 5) The waveguide according to claim 5, wherein the light-frequency-converting substance is urea. ### Claim 7 (depends on 1) The waveguide according to claim 1, wherein the cladding is transparent. ### Claim 8 A method of identifying a waveguide that is too severely curved, wherein the waveguide comprises a core, a cladding, and a coating, wherein the coating is immediately adjacent to the core, and wherein the coating comprises a light-frequency-converting substance and the light-frequency converting substance converts UV or IR light into visible light, the method comprising: laying the waveguide, coupling in a UV light and/or an IR light, and visually inspecting the waveguide for escaping visible light so that if an escape of visible light is identified at a bend point, the waveguide is too severely curved, wherein the coating is disposed between the core and the cladding. ### Claim 9 (depends on 1) The waveguide according to claim 1, wherein the waveguide is an optical fiber. ### Claim 10 (depends on 8) The method according to claim 8, wherein the waveguide is an optical fiber. ### Claim 11 (depends on 3) The waveguide according to claim 3, wherein the light-frequency-converting substance is a fluorescent dye. ### Claim 12 (depends on 3) The waveguide according to claim 3, wherein the light-frequency-converting substance is at least one selected from the group consisting of a coumarin dye, a cyanine dye, a flavine dye, a luciferin dye, a phycobilin dye, a rhodamine dye, and a safranin dye. ### Claim 13 (depends on 1) The waveguide according to claim 1, wherein the cladding comprises at least one material selected from the group consisting of a polyimide, an acrylic, and a silicone. ### Claim 14 (depends on 8) The method according to claim 8, wherein the light-frequency-converting substance has a concentration of less than 5.0 wt. % and more than 0.1 wt. %, based on a total mass of the coating. ### Claim 15 (depends on 8) The method according to claim 8, wherein the light-frequency-converting substance is selected such that the light-frequency-converting substance generates a low-frequency light from a higher-frequency light or a higher-frequency light from a low-frequency light. ### Claim 16 (depends on 15) The method according to claim 15, wherein the light-frequency-converting substance generates a low-frequency light from a higher-frequency light, and wherein the light-frequency-converting substance is at least one selected from the group consisting of a coumarin dye, a cyanine dye, a flavine dye, a luciferin dye, a phycobilin dye, a rhodamine dye, and a safranin dye. ### Claim 17 (depends on 15) The method according to claim 15, wherein the light-frequency-converting substance generates a higher-frequency light from a low-frequency light, and wherein the light-frequency-converting substance is urea. ### Claim 18 (depends on 8) The method according to claim 8, wherein the cladding is transparent.