# US 8,540,701 B2 · Hair treatment system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,540,701 B2 - Document ID: US8540701B2 - Status: Granted - Kind: B2 - Application number: 11/072,698 - Filed: 2005-03-04 - Published: 2006-09-07 - Granted: 2013-09-24 - Earliest claimed: 2005-03-04 - Assignees: The Invention Science Fund I, LLC - Applicants: Bran Ferren; Muriel Y. Ishikawa; Edward K. Y. Jung; Nathan P. Myhrvold; Clarence T. Tegreene; Lowell L. Wood, Jr. - Inventors: Bran Ferren; Muriel Y. Ishikawa; Edward K. Y. Jung; Nathan P. Myhrvold; Clarence T. Tegreene; Lowell L. Wood, Jr. - Web page: https://patentgrep.com/patent/US8540701B2 ## CPC - A61B 18/203: {applying laser energy to the outside of the body} - A61B 2018/00452: {Skin} - A61B 2018/00476: {Hair follicles} - A61B 2018/208: {with multiple treatment beams not sharing a common path, e.g. non-axial or parallel} - A61B 2090/065: {for measuring contact or contact pressure} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Embodiments of methods and systems for hair treatment are disclosed. According to various embodiments, light is used to shave, trim, or otherwise modify hair shafts. ## Claims ### Claim 1 A hair removal method comprising: a) manually positioning a handheld device containing a light source adjacent to a skin surface; b) detecting or determining a distance of said light source from the skin surface with a proximity sensor in said handheld device; and c) if said determined distance is within a specified range, activating said light source responsive to said detecting or determining a distance of said light source from the skin surface with a proximity sensor in said handheld device to generate a highly convergent beam of a frequency band significantly absorbed by hair and having a narrow, spatially limited beam waist located at a selected distance above the skin surface, wherein said selected distance is between about 25μm and about 300 μm. ### Claim 2 (depends on 1) The method of claim 1, wherein said light source is a laser, a laser diode, or a light-emitting diode. ### Claim 3 (depends on 1) The method of claim 1, wherein said beam waist has a diameter of between about 25 μm and about 300 μm. ### Claim 4 (depends on 1) The method of claim 1, wherein said specified range is selected so that said beam waist is located at said selected distance above the skin surface when said light source is within said specified range of the skin surface. ### Claim 5 (depends on 1) The method of claim 1, wherein said selected distance is located just above the skin surface at the base of one or more hair shafts. ### Claim 6 (depends on 1) The method of claim 1, including generating a beam having an axis and an angle of convergence of between about 25 and about 70 degrees relative to the axis of said beam. ### Claim 7 A hair removal method comprising: a) manually positioning a handheld device containing a light source adjacent to a skin surface; b) detecting or determining a distance of said light source from the skin surface with a proximity sensor in said handheld device; and if said determined distance is within a specified range, activating said light source responsive to said detecting or determining a distance of said light source from the skin surface with a proximity sensor in said handheld device to generate a highly convergent beam of a frequency band significantly absorbed by hair and having a narrow, spatially limited beam waist located at a selected distance above the skin surface, wherein the light fluence at said beam waist is between about 4 and about 100 times the light fluence at said skin surface. ### Claim 8 (depends on 1) The method of claim 1, including discontinuing exposure of a skin region to said beam prior to injury of the skin region by said beam. ### Claim 9 (depends on 1) The method of claim 1, including delivering said highly convergent beam to said skin surface through a light-conducting medium interposed between said handheld device and said skin surface. ### Claim 10 (depends on 9) The method of claim 9, wherein said light-conducting medium is a light activated medium. ### Claim 11 (depends on 8) The method of claim 8, including discontinuing exposure of the skin region by at least one of moving the handheld device along the skin surface to an adjacent skin region, deactivating the light source, and blocking the delivery of light from the light source. ### Claim 12 A hair removal method comprising: a) manually positioning a handheld device containing a light source adjacent to a skin surface; b) detecting or determining a distance of a portion of said handheld device from the skin surface with a proximity sensor in said handheld device; and c) if said determined distance is within a specified range, activating said light source responsive to said detecting or determining a distance of said portion of said handheld device from the skin surface with a proximity sensor in said handheld device to generate a highly convergent beam of a frequency band significantly absorbed by hair and having a narrow, spatially limited beam waist located at a selected distance above the skin surface, wherein the light fluence at said beam waist is between about 4 and about 100 times the light fluence at said skin surface. ### Claim 13 A hair removal method comprising: a) manually positioning a handheld device containing a light source adjacent to a skin surface; b) detecting or determining a distance of a portion of said handheld device from the skin surface with a proximity sensor in said handheld device; and if said determined distance is within a specified range, activating said light source responsive to said detecting or determining a distance of said portion of said handheld device from the skin surface with a proximity sensor in said handheld device to generate a highly convergent beam of a frequency band significantly absorbed by hair and having a narrow, spatially limited beam waist located at a selected distance above the skin surface, wherein said selected distance is between about 25μm and about 300μm. ### Claim 14 (depends on 12) The method of claim 12, wherein said specified range is selected so that said beam waist is located at said selected distance above the skin surface when said portion of said handheld device is within said specified range of the skin surface. ### Claim 15 (depends on 12) The method of claim 12, including generating a beam having an axis and an angle of convergence of between about 25 and about 70 degrees relative to the axis of said beam.