# US 2018/0022631 A1 · Method for cutting glass using a laser, and glass produced according to the method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0022631 A1 - Document ID: US20180022631A1 - Status: Published application - Kind: A1 - Application number: 15/674,124 - Filed: 2017-08-10 - Published: 2018-01-25 - Earliest claimed: 2015-03-27 - Assignees: Schott AG - Applicants: Schott AG - Inventors: Dirk Förtsch; Stephan Behle; Peter Thomas - Web page: https://patentgrep.com/patent/US20180022631A1 ## CPC - C03B 33/091: {using at least one focussed radiation beam, e.g. laser beam (C03B33/0955 takes precedence)} - B65G 49/065: {supported partially or completely on fluid cushions, e.g. a gas cushion (in general B65G51/00)} - C03B 33/0235: {Ribbons} - C03B 33/03: Glass cutting tables; Apparatus for transporting or handling sheet glass during the cutting or breaking operations - C03C 3/064: containing boron - C03C 3/066: containing zinc - C03C 3/089: containing boron - C03C 3/091: containing aluminium - C03C 3/093: containing zinc or zirconium - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - B65G: TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS (packaging B65B; handling thin or filamentary materials, e.g. paper sheets or thread, B65H; cranes B66C; portable mobile or lifting or hauling appliances, e.g. hoists, B66D; devices for lifting or lowering goods for loading or unloading purposes, e.g. fork-lift trucks, B66F9/00; emptying bottles, jars, casks, barrels or similar containers, not otherwise provided for, B67C9/00; delivering or transferring liquids B67D; filling or discharging vessels for liquefied, solidified or compressed gases F17C; pipe-line systems for fluids F17D) - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS ## Abstract A method for cutting thin glass, wherein the thin glass is heated with a laser beam along a path forming a cutting line moving along a forward feed direction, such that a crack propagates along the cutting line and cuts through the thin glass. The laser beam is formed by a beam-forming optic in such a way that the beam profile thereof has an elongated shape. The laser beam is orientated on the surface of the thin glass such that the longitudinal direction thereof is aligned in the feed direction. The elongated shape of the beam profile is asymmetric, such that the intensity course differs at the ends of the beam profile in such a way that the increase in intensity at the front end crossing the thin glass first is steeper than the drop in intensity at the opposite rear end. ## Claims ### Claim 1 A method for separating a thin glass with a thickness less than 250 μm, said method comprising the steps of: heating the thin glass with a laser beam along a path forming a parting line, progressing along a forward feed direction, so that based on a thus produced temperature difference of a heated glass relative to a surrounding glass, a mechanical stress is created in the thin glass and a crack propagates following the mechanical stress along the parting line, separating the thin glass; forming the laser beam by a beam-forming optic in such a way that a beam profile thereof has an elongated shape, said beam profile has a front end and an opposite rear end; and directing the laser beam onto a surface of the thin glass such that a longitudinal direction thereof is aligned in the forward feed direction, and wherein the elongated shape of the beam profile is asymmetric, such that an intensity progression differs at said ends of the beam profile in such a way that an increase in intensity at the front end crossing the thin glass first is steeper than a drop in intensity at the opposite rear end. ### Claim 2 (depends on 1) The method according to claim 1, including a further step of cooling the thin glass by way of a cooling jet, after having been heated. ### Claim 3 (depends on 2) The method according to claim 2, wherein said cooling jet is in the form of at least one of a moistened gas jet that has a relative humidity of 70% to 100%, or which comprises a liquid phase, an aerosol jet, a liquid jet, and a droplet jet with successively abutting droplets. ### Claim 4 (depends on 1) The method according to claim 1, wherein said front end of the beam profile that crosses over the thin glass first during a feed motion is formed by an edge that progresses transversely to the forward feed direction. ### Claim 5 (depends on 1) The method according to claim 1, wherein said asymmetrical beam profile is produced by way of at least one of: shading of the beam profile at its front end, by beam formation by way of a diffractive optical element, and a cylindrical lens that is tilted relative to a beam direction of the laser beam, so that an optical axis of the cylindrical lens is positioned diagonally to the beam direction, at an angle in the range of 25° to 75° relative to the direction of the beam. ### Claim 6 (depends on 5) The method according to claim 5, wherein during a cross-over of the beam profile a maximum temperature difference between an irradiated side and an opposite side of the thin glass is built up within a distance of less than 5 millimeters. ### Claim 7 (depends on 6) The method according to claim 6, wherein during cross-over of the beam profile a temperature difference of at least 20° C. between the irradiated side and the opposite side of the thin glass is built up. ### Claim 8 (depends on 1) The method according to claim 1, wherein the laser beam crosses over the thin glass with a speed of at least 3 meters per minute. ### Claim 9 (depends on 1) The method according to claim 1, wherein the laser beam is formed such that the rear end of the beam profile has a steadily decreasing intensity towards the end. ### Claim 10 (depends on 1) The method according to claim 1, wherein the laser beam is formed such that said front end of the beam profile has a concave recess. ### Claim 11 A device, comprising: a laser to irradiate a thin glass with a laser beam that is absorbed by the thin glass, therefore heating the thin glass, said laser beam has a beam profile with a front end and an opposite rear end; a beam-forming optic to form the beam profile of the laser beam that is produced by the laser; a feed device to move the thin glass relative to an impingement location of the laser beam along an intended parting line, so that based on a thus produced temperature difference of a glass that is heated along a parting line relative to a surrounding glass, a mechanical stress is produced in the glass and a crack propagates following the mechanical stress along the parting line, separating the thin glass, wherein said beam-forming optic is created to form laser beam in such a way that its beam profile has an elongated shape and wherein the laser beam is directed onto a surface of thin glass such that a longitudinal direction thereof is aligned in a feed direction, and wherein the elongated shape of the beam profile is asymmetrical, such that an intensity progression differs at said ends of the beam profile in such a way that an increase in intensity at the front end crossing the thin glass first is steeper than a drop in intensity at the opposite rear end. ### Claim 12 (depends on 11) The device according to claim 11, further including a cooling jet generator that produces a cooling jet that impinges onto the thin glass along the parting line, offset to the laser beam, so that during forward feed, a point of the thin glass that is positioned on the parting line first passes through an impingement location of the laser beam and then through an impingement location of the cooling jet. ### Claim 13 (depends on 12) The device according to claim 12, wherein the cooling jet generator includes a device for production of a moistened gas jet with a relative humidity of 70% to 100%, and a liquid phase. ### Claim 14 (depends on 11) The device according to claim 11, wherein the beam forming optic is designed to produce the beam profile whose front end has a concave recess. ### Claim 15 (depends on 11) The device according to claim 11, wherein the laser is a CO2 laser. ### Claim 16 (depends on 11) The device according to claim 11, wherein the beam-forming optic includes at least one of the following elements: a shading element in order to shade the front end of the beam profile; a diffractive optical element; and a cylindrical lens that is tilted relative to a beam direction of the laser beam, at an angle in the range of 25° to 75° relative to the direction of the beam. ### Claim 17 A method, comprising the steps of: heating a thin glass element, with a maximum thickness of 250 μm, with a laser beam along a path forming a parting line, progressing along a forward feed direction, so that based on a thus produced temperature difference of a heated glass relative to a surrounding glass, a mechanical stress is created in the thin glass element and a crack propagates following the mechanical stress along the parting line, separating the thin glass element; forming the laser beam by a beam-forming optic in such a way that a beam profile thereof has an elongated shape, said beam profile has a front end and an opposite rear end; directing the laser beam onto a surface of the thin glass element such that a longitudinal direction thereof is aligned in the forward feed direction, and wherein the elongated shape of the beam profile is asymmetric, such that an intensity progression differs at said ends of the beam profile in such a way that an increase in intensity at the front end crossing the thin glass element first is steeper than a drop in intensity at the opposite rear end; and cutting at least one edge of said thin glass element by way of a laser-stress crack separation such that—for breaks originating from the at least one edge under bending stress—the thin glass element has a Weibull distribution with a Weibull module of at least m=4.5. ### Claim 18 (depends on 17) The method according to claim 17, wherein said thin glass element has a Weibull distribution for breaks under bending stress, wherein a median value of a bending stress during a break of a sample is higher than 200 MPa. ### Claim 19 (depends on 17) The method according to claim 17, wherein said thin glass element is subjected to a tensile stress σapp that is less than 1.15 · Min  ( σ _ a - Δ a  0.4 · ( 1 - ln  ( A ref A App  Φ ) ) , σ _ e - Δ e  0.4 · ( 1 - ln  ( L ref L App  Φ ) ) ) wherein σa and σe are median values of the tensile stress during breakage of samples of the thin glass element, wherein Lref describes an edge length and Aref describes a surface area of the samples, wherein σa is a median value of the tensile stress during a fracture in the surface area of the sample and σe is a median value of the tensile stress during a crack originating from an edge of the sample, and wherein Δe and Δa describe a standard deviation of the mean values σe or respectively σa, and wherein Aapp is a surface area of the thin glass element and Lapp is a combined edge length of edges of the glass element opposite one another and Φ is a predetermined maximum breakage ratio within a time period of at least half a year. ### Claim 20 (depends on 17) The method according to claim 17, wherein the thin glass element is subjected to a tensile stress σapp that is less than 0.93 · Min  ( σ _ a - Δ a  0.4 · ( 1 - ln  ( A ref A app  Φ ) ) , σ _ e - Δ e  0.4 · ( 1 - ln  ( L ref L app  Φ ) ) ) ### Claim 21 (depends on 20) The method according to claim 20, wherein the thin glass element is a thin glass ribbon that is wound onto a roll. ### Claim 22 (depends on 21) The method according to claim 21, wherein an inside radius of the wound thin glass is in the range of R min = 〈 R 〉 · { [ 0.7 + exp  ( s 〈 R 〉 · 0.053 - 2.3 ) ] · ( 2 - e - t ) }   to R max = 〈 R 〉 · { [ 3.4 + exp  ( s 〈 R 〉 · 0.05 - 2.1 ) ] · ( 2 - e - t ) }   w wherein is a mean value and s = 1 N - 1  ∑ R i 2 - 〈 R 〉 2 is the variance of a bending radii Ri at the breakage of a plurality N of samples of same glass material with same thickness and same glass edges as the glass material of said thin glass element, wherein Ri represents the bending radii at which the samples respectively break, and t represents a minimum duration in days over which the thin glass roll survives without breaking.