# US 2014/0155754 A1 · Hair treatment device with hair detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155754 A1 - Document ID: US20140155754A1 - Status: Published application - Kind: A1 - Application number: 14/236,412 - Filed: 2012-08-08 - Published: 2014-06-05 - Earliest claimed: 2011-08-22 - Assignees: Koninklijke Philips N.V. - Inventors: Babu Varghese; Rieko Verhagen; Natallia Eduardauna Uzunbajakava - Web page: https://patentgrep.com/patent/US20140155754A1 ## CPC - A61B 18/20: using laser - A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)} - A61B 18/203: {applying laser energy to the outside of the body} - B26B 19/48: Accessory implements for carrying out a function other than cutting hair, e.g. attachable appliances for manicuring (massage means per se A61H7/00 - A61H23/00) - A61B 5/0077: {Devices for viewing the surface of the body, e.g. camera, magnifying lens} - A61B 5/448: {Hair evaluation, e.g. for hair disorder diagnosis} - A61B 5/6898: {Portable consumer electronic devices, e.g. music players, telephones, tablet computers} - A61B 2018/00476: {Hair follicles} - A61B 2018/00904: {Automatic detection of target tissue} - F04C 2270/041: Controlled or regulated - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - B26B: HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR (for harvesting A01D; for horticulture, for forestry A01G; for butchering or meat treatment A22; for manufactering or repairing footwear A43D; nail clippers or cutters A45D29/02; kitchen equipment A47J; {vegetable slicers, julienne cutters and similar devices and holders therefor, B26D3/28}; for surgical purposes A61B; for metal B23D; cutting by abrasive fluid jets B24C5/02; plier-like tools with cutting edges B25B7/22; pincers B25C11/02; handles for hand implements, in general B25G; guillotine-type cutters B26D; {perforating by non-mechanical means, e.g. by fluid jet, B26F1/26}; for erasing B43L19/00; for textile materials D06H) - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS ## Abstract The invention provides a hair treatment device (40) comprising a light-based detector (10) for detecting a hair (22) near a skin surface (21) and a method for detecting a hair (22) near a skin surface (21). The detector (10) comprises a light source (11), optical elements (14, 16, 17, 18) and a polarization-sensitive light sensor (12, 13). The light source (11) generates a light beam (31) and the optical elements (14, 16, 17, 18) focus the light beam (31) at a hair (22) near the skin surface (21). The polarization-sensitive light sensor (12, 13) is provided for detecting light interacted with the hair (22) or the skin surface (21) and having a predefined linear polarization. The light source (11) and/or the optical elements (14, 16, 17, 8) are arranged to cause the light beam (31), when reaching the skin surface (21), to have a polarization direction which is time-invariant and spatially variant in cross-sections of the 10 light beam. ## Claims ### Claim 1 A hair treatment device comprising a light-based detector for detecting a hair near a skin surface, the detector comprising: a light source for generating a light beam, optical elements for focusing the light beam at the hair near the skin surface, and a polarization-sensitive light sensor for detecting light interacted with the hair or the skin surface and having a predefined linear polarization, wherein the light source and/or the optical elements are arranged to cause the light beam, when reaching the hair or the skin surface, to have a polarization direction which is time-invariant and spatially variant in cross-sections of the light beam. ### Claim 2 (depends on 1) A hair treatment device as claimed in claim 1, wherein the light source and/or the optical elements are arranged to cause the light beam to have a radial or an azimuthal polarization direction in cross-sections of the light beam. ### Claim 3 (depends on 1) A hair treatment device as claimed in claim 1, wherein the light source is operative to produce a light beam having a polarization direction which is time-invariant and spatially variant in cross-sections of the light beam. ### Claim 4 (depends on 3) A hair treatment device as claimed in claim 3, wherein the light source comprises a conical Brewster prism. ### Claim 5 (depends on 1) A hair treatment device as claimed in claim 1, wherein the optical elements comprise a spatially varying retarder. ### Claim 6 (depends on 1) A hair treatment device as claimed in claim 1, wherein the optical elements comprise an LCoS chip. ### Claim 7 (depends on 1) A hair treatment device as claimed in claim 1, further comprising a second polarization-sensitive sensor for detecting light interacted with the hair or the skin surface and having a polarization orthogonal to the predefined linear polarization. ### Claim 8 (depends on 1) A hair treatment device according to claim 1, the device further comprising a hair-cutting laser source for generating a hair-cutting laser beam and a processor which is coupled to the light-based detector, wherein the processor is arranged to activate the hair-cutting laser source in a focal position of the hair-cutting laser beam near the skin surface in which the light-based detector has detected the presence of the hair. ### Claim 9 A method for detecting a hair near a skin surface, the method comprising: generating a light beam, focusing the light beam at a hair near the skin surface, and detecting light interacted with the hair or the skin surface and having a predefined linear polarization, wherein the generating and/or the focusing cause the light beam, when reaching the hair or the skin surface, to have a polarization direction which is time-invariant and spatially variant in cross-sections of the light beam.