WO2013084879A1 - Method for cutting toughened glass plates and device for cutting toughened glass plates - Google Patents

Method for cutting toughened glass plates and device for cutting toughened glass plates Download PDF

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Publication number
WO2013084879A1
WO2013084879A1 PCT/JP2012/081371 JP2012081371W WO2013084879A1 WO 2013084879 A1 WO2013084879 A1 WO 2013084879A1 JP 2012081371 W JP2012081371 W JP 2012081371W WO 2013084879 A1 WO2013084879 A1 WO 2013084879A1
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Prior art keywords
tempered glass
glass plate
cutting
irradiation energy
irradiation
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PCT/JP2012/081371
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French (fr)
Japanese (ja)
Inventor
齋藤　勲
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旭硝子株式会社
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Priority claimed from JP2011267747A external-priority patent/JP2015034096A/en
Application filed by 旭硝子株式会社 filed Critical 旭硝子株式会社
Publication of WO2013084879A1 publication Critical patent/WO2013084879A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B33/00—Severing cooled glass
    • C03B33/02—Cutting or splitting sheet glass or ribbons; Apparatus or machines therefor
    • C03B33/04—Cutting or splitting in curves, especially for making spectacle lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36—Removing material
    • B23K26/40—Removing material taking account of the properties of the material involved
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B33/00—Severing cooled glass
    • C03B33/09—Severing cooled glass by thermal shock
    • C03B33/091—Severing cooled glass by thermal shock using at least one focussed radiation beam, e.g. laser beam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Definitions

  • the present invention relates to a method for cutting a tempered glass plate and a tempered glass plate cutting device, and more particularly to a method for cutting a tempered glass plate using internal heating by a laser beam and a tempered glass plate cutting device.
  • a glass plate is used as a display cover or a substrate. Due to demands for thinning and weight reduction in portable devices, thinning and weight reduction have been achieved by using high strength tempered glass plates.
  • the cutting of the glass plate is usually performed by introducing a scribe line mechanically into the main surface with a hard roller or chip such as diamond and applying a bending force along the scribe line.
  • a scribe line mechanically into the main surface with a hard roller or chip such as diamond and applying a bending force along the scribe line.
  • a lot of fine cracks are generated on the cut end face of the glass plate by introducing the scribe line. Accordingly, there is a problem that a sufficient strength cannot be obtained at the cut end despite the tempered glass plate.
  • Patent Document 1 discloses a method of cutting a glass plate with a laser beam.
  • the inventor has found the following problems regarding cutting of a tempered glass plate using a laser beam.
  • the cutting line may deviate from the planned cutting line and the cut out tempered glass panel may be defective in dimensions. was there.
  • the present invention has been made in view of the above, and an object of the present invention is to provide a method for cutting a tempered glass plate that suppresses a dimensional defect of the cut tempered glass panel.
  • the method for cutting a tempered glass sheet according to the first aspect of the present invention is as follows.
  • a tempered glass plate comprising a surface layer and a back surface layer having a residual compressive stress, and an intermediate layer formed between the surface layer and the back surface layer and having an internal residual tensile stress CT (MPa) is applied to the tempered glass plate.
  • a method of cutting a tempered glass plate that is cut by moving the irradiation region of the irradiated laser beam, U CT ⁇ CT 2 , where DOL ( ⁇ m) is the thickness of the surface layer and the back layer, t 1 ( ⁇ m) is the thickness of the tempered glass plate, and Y (MPa) is the Young's modulus of the tempered glass plate.
  • the strain energy U CT (J / m 2 ) per unit area based on the internal residual tensile stress CT expressed by ⁇ (t 1 ⁇ 2 ⁇ DOL) ⁇ / (2 ⁇ Y) is 2.5 J / m 2 or more.
  • the cutting line of the tempered glass plate includes a corner portion and a straight portion, and the tempered glass at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated on the tempered glass plate at the straight portion.
  • the switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. is there.
  • the method for cutting a strengthened glass sheet according to the second aspect of the present invention is the first aspect,
  • the effective output of the laser light incident on the tempered glass plate is Pe (W)
  • the scanning speed of the laser light is v (mm / s)
  • the absorption coefficient of the tempered glass plate with respect to the laser light is ⁇ ( mm ⁇ 1 )
  • the thickness of the tempered glass plate is t 2 (mm)
  • the linear expansion coefficient of the tempered glass plate is ⁇ L (K ⁇ 1 )
  • the density of the tempered glass plate is ⁇ (g / mm 3 ).
  • the cutting index K (N / mm) is 150 N / mm or less.
  • the method for cutting a strengthened glass sheet according to the third aspect of the present invention is the first or second aspect,
  • the tempered glass plate and the laser beam are expressed as follows: 0 ⁇ ⁇ t, where ⁇ (mm ⁇ 1 ) is the absorption coefficient of the tempered glass plate with respect to the laser beam and t 2 (mm) is the thickness of the tempered glass plate. 2 ⁇ 3.0 is satisfied.
  • the method for cutting a strengthened glass sheet according to the fourth aspect of the present invention in any one of the first to third aspects, as the residual tensile stress of the intermediate layer increases, the switching speed from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the linear portion is increased.
  • Switching from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the straight portion is performed by increasing the moving speed of the irradiation region of the laser light.
  • the method for cutting a tempered glass sheet according to a sixth aspect of the present invention in any one of the first to fifth aspects, By reducing the output of the laser beam, the irradiation energy E2 at the corner portion is switched to the irradiation energy E1 at the straight portion.
  • a method for cutting a strengthened glass sheet according to a seventh aspect of the present invention in any one of the first to sixth aspects, By increasing the area of the laser light irradiation region, the irradiation energy E2 at the corner portion is switched to the irradiation energy E1 at the straight portion.
  • the method for cutting a strengthened glass sheet according to the eighth aspect of the present invention is the method according to any one of the first to seventh aspects, As the absorption coefficient ⁇ of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
  • the method for cutting a strengthened glass sheet according to the ninth aspect of the present invention in any one of the first to eighth aspects, As the thermal expansion coefficient of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
  • the method for cutting a strengthened glass sheet according to the tenth aspect of the present invention is the method according to any one of the first to ninth aspects, As the thickness of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are increased.
  • a gas is blown from the incident side of the laser beam to the irradiation region of the laser beam of the tempered glass plate to cool it.
  • the tempered glass sheet cutting method according to the twelfth aspect of the present invention in the eleventh aspect, Gas is blown from the laser beam emission side to the corner portion of the tempered glass plate to cool it.
  • the tempered glass sheet cutting device is: Laser that irradiates the tempered glass plate with a tempered glass plate that is formed between the surface layer and the back surface layer having a residual compressive stress and an intermediate layer that has an internal residual tensile stress.
  • a tempered glass sheet cutting device that cuts by moving an irradiation area of light, A glass holding part for holding the tempered glass plate; A laser output unit for outputting a laser beam for cutting the tempered glass plate; A control unit for controlling the laser output unit, The cutting line of the tempered glass plate includes a corner portion and a straight portion, The controller is The irradiation energy E2 per unit irradiation area of the laser light irradiated to the tempered glass plate at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated to the tempered glass plate at the linear portion.
  • the switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. is there.
  • FIG. 4 is a cross-sectional view taken along line AA in FIG. 3.
  • FIG. 4 is a cross-sectional view taken along line BB in FIG. 3.
  • FIG. It is a figure for demonstrating the cutting method of the tempered glass board which concerns on Embodiment 1.
  • FIG. It is the graph which showed typically switching of unit irradiation energy E in a straight part and a corner part. It is a table
  • FIG. 6 is a table showing laser wavelength ⁇ , internal strain energy U CT , critical irradiation energy Ec, and various conditions for deriving both of samples 1 to 12; It is a graph which shows the internal strain energy UCT dependence of the critical irradiation energy Ec shown in the table
  • FIG. 1 is a cross-sectional view of a tempered glass plate 10 before irradiation with laser light.
  • the direction of the arrow indicates the direction of action of the residual stress
  • the size of the arrow indicates the magnitude of the stress.
  • the tempered glass plate 10 includes a front surface layer 13 and a back surface layer 15, and an intermediate layer 17 provided between the front surface layer 13 and the back surface layer 15. Compressive stress remains on the front surface layer 13 and the back surface layer 15 by the following air cooling strengthening method or chemical strengthening method. Further, as a reaction, tensile stress remains in the intermediate layer 17.
  • the tempered glass plate 10 is produced by, for example, an air cooling strengthening method or a chemical strengthening method.
  • strengthening is selected according to a use.
  • an automobile window glass an architectural window glass, a glass substrate for PDP (Plasma Display Panel), and a cover glass, alkali aluminosilicate glass or soda lime glass is used as the reinforcing glass.
  • the air-cooling strengthening method rapidly cools the glass near the softening point from the front and back surfaces, and creates a temperature difference between the front and back surfaces of the glass and the inside, so that the surface layer and the back surface layer where compressive stress remains are formed. Form.
  • the air cooling strengthening method is suitable for strengthening thick glass.
  • the front and back surfaces of glass are ion-exchanged, and ions having a small ion radius (for example, Li ions and Na ions) contained in the glass are replaced with ions having a large ion radius (for example, K ions).
  • ions having a small ion radius for example, Li ions and Na ions
  • ions having a large ion radius for example, K ions.
  • the chemical strengthening method is suitable for strengthening alkali aluminosilicate glass or soda lime glass.
  • FIG. 2 is a schematic diagram showing a distribution of residual stress of the tempered glass plate before irradiation with laser light.
  • the compressive stress (> 0) remaining on the front surface layer 13 and the back surface layer 15 tends to gradually decrease from the front surface 12 and the back surface 14 of the tempered glass plate 10 toward the inside.
  • the tensile stress (> 0) remaining in the intermediate layer 17 tends to gradually decrease from the inside of the glass toward the front surface 12 and the back surface 14.
  • CS is the maximum residual compressive stress (surface compressive stress) (> 0) in the surface layer 13 and the back layer 15
  • CT is the internal residual tensile stress in the intermediate layer 17 (average value of residual tensile stress in the intermediate layer 17).
  • DOL indicates the thickness of the front surface layer 13 and the back surface layer 15
  • t indicates the thickness of the tempered glass plate 10, respectively. Therefore, the thickness of the intermediate layer 17 is t ⁇ 2 ⁇ DOL.
  • the internal residual tensile stress CT (MPa) of the tempered glass plate is usually measured by measuring the surface compressive stress CS (MPa) and the thickness DOL ( ⁇ m) of the surface layer 13 and the back surface layer 15, and the measured values and strengthening. It is calculated using the thickness t 1 ([mu] m) and formula 1 below color of the glass plate.
  • CT (CS ⁇ DOL) / (t 1 ⁇ 2 ⁇ DOL) Equation 1
  • the strain energy per unit area (hereinafter simply referred to as “internal strain energy”) U CT (J / m 2 ) by the internal residual tensile stress CT is expressed as follows using the Young's modulus Y (MPa) of the tempered glass sheet. It can be obtained from Equation 2.
  • U CT ⁇ CT 2 ⁇ (t 1 ⁇ 2 ⁇ DOL) ⁇ / (2 ⁇ Y) Equation 2
  • the inventor investigated the minimum value (hereinafter referred to as critical irradiation energy) Ec of the irradiation energy E of the laser light necessary for cutting, for the tempered glass plate having various internal strain energies U CT .
  • critical irradiation energy Ec of the irradiation energy E of the laser light necessary for cutting
  • U CT internal strain energy
  • the critical irradiation energy Ec increases rapidly (specifically, about several times), and the cutting accuracy I also found it worse.
  • the critical irradiation energy Ec is substantially constant if the material, thickness and laser wavelength of the tempered glass plate are the same.
  • the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the front surface layer 13 and the back surface layer 15 can be adjusted by the strengthening process conditions.
  • the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the front surface layer 13 and the back surface layer 15 can be adjusted by the cooling rate of the glass in the case of the air cooling strengthening method.
  • the maximum residual compressive stress CS, internal residual tensile stress CT, and thickness DOL of the surface layer 13 and the back surface layer 15 are determined by immersing glass in a treatment liquid (for example, KNO 3 molten salt).
  • the front surface layer 13 and the back surface layer 15 of the present embodiment have the same thickness DOL and the maximum residual compressive stress CS, but may have different thicknesses and maximum residual compressive stress.
  • FIG. 3 is a diagram for explaining a method of cutting a tempered glass sheet.
  • the surface 12 of the tempered glass plate 10 is irradiated with laser light 20, and the irradiation region 22 of the laser light 20 is moved (scanned) on the surface 12 of the tempered glass plate 10, thereby strengthening glass. Stress is applied to the plate 10 to cut the tempered glass plate 10.
  • an initial crack is formed in advance at the cutting start position.
  • the method for forming the initial crack may be a general method, for example, a cutter, a file, or a laser. In the internal heating cutting using laser light, it is not necessary to form scribe lines (groove lines) along the planned cutting line on the surface 12 of the tempered glass plate 10.
  • the irradiation region 22 of the laser beam 20 is moved in a straight line shape or a curved shape along the planned cutting line from the end of the tempered glass plate 10 toward the inside.
  • the crack 30 is extended from the end of the tempered glass plate 10 toward the inside, and the tempered glass plate 10 is cut.
  • the holder supporting the tempered glass plate 10 may be moved or rotated, or the light source of the laser light 20 is moved. May be. Further, a mirror provided in the middle of the path of the laser beam 20 may be rotated.
  • the irradiation region 22 of the laser beam 20 includes the thickness of the tempered glass plate 10, the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the surface layer 13 and the back surface layer 15.
  • the laser beam 20 is moved at a speed corresponding to the output of the light source.
  • the light source of the laser light 20 is not particularly limited.
  • a UV laser (wavelength: 355 nm), a green laser (wavelength: 532 nm), a semiconductor laser (wavelength: 808 nm, 940 nm, 975 nm), a fiber laser (wavelength: 1060 to 1100 nm), YAG laser (wavelength: 1064 nm, 2080 nm, 2940 nm), laser using a mid-infrared light parametric oscillator (wavelength: 2600 to 3450 nm), and the like.
  • the oscillation method of the laser beam 20 there is no limitation on the oscillation method of the laser beam 20, and either a CW laser that continuously oscillates the laser beam or a pulse laser that intermittently oscillates the laser beam can be used.
  • the intensity distribution of the laser beam 20 is not limited, and may be a Gaussian type or a top hat type.
  • the laser light 20 emitted from the light source is condensed by a condenser lens or the like and imaged on the surface 12 of the tempered glass plate 10.
  • the condensing position of the laser light 20 may be on the laser light source side or the back surface 14 side with respect to the front surface 12 of the tempered glass plate 10. Further, the condensing position of the laser beam 20 may be in the tempered glass plate 10 as long as the heating temperature does not become too high, that is, the condensing area can keep the annealing point or less.
  • the optical axis of the laser beam 20 may be perpendicular to the surface 12 on the surface 12 of the tempered glass plate 10, for example, as shown in FIG.
  • the tempered glass board 10 can be cut
  • heating of the intermediate layer 17 in the irradiation region 22 of the laser light 20 at a temperature equal to or lower than the annealing point controls the extension of the crack 30 generated in the tempered glass plate 10 by the residual tensile stress of the intermediate layer 17.
  • the tempered glass plate 10 can be cut by the crack 30 caused by the residual tensile stress.
  • the intermediate layer 17 is heated at a temperature below the annealing point because when the heating is performed above the annealing point, the glass becomes high temperature and a viscous flow easily occurs even in a short time during which the laser beam passes. This is because the compressive stress generated by the laser beam is relieved by this viscous flow.
  • the value t 2 (mm) of the thickness (plate thickness) t of the tempered glass plate 10 differs from the value t 1 ( ⁇ m) in Equations 1 and 2 only in units.
  • ⁇ ⁇ t 2 By making ⁇ ⁇ t 2 greater than 0 and 3.0 or less, the laser light 20 reaches the inside without being absorbed by the surface of the tempered glass plate 10. It can be heated sufficiently. As a result, the stress generated in the tempered glass plate 10 changes from the state shown in FIG. 1 to the state shown in FIG. 4 or FIG.
  • FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and includes a laser light irradiation region.
  • FIG. 5 is a cross-sectional view taken along line BB in FIG. 3, and is a rear cross section from the cross section shown in FIG.
  • “rear” means the rear of the laser beam 20 in the scanning direction. 4 and 5, the direction of the arrow indicates the direction of the applied stress, and the length of the arrow indicates the magnitude of the stress.
  • a tensile stress is generated in the intermediate layer 17 in the cross section behind the cross section shown in FIG. 4, as shown in FIG. 5.
  • This tensile stress is larger than the residual tensile stress, and a crack 30 is formed in a portion where the tensile stress reaches a predetermined value.
  • the crack 30 penetrates from the front surface 12 to the back surface 14 of the tempered glass plate 10, and the cutting shown in FIG. 3 is a so-called full cut cutting.
  • the tip position of the crack 30 is moved so as to follow the position of the irradiation region 22. That is, in the cutting method shown in FIG. 3, when the tempered glass plate 10 is cut, the extension direction of the crack 30 is controlled by the tensile stress (see FIG. 5) generated behind the scanning direction of the laser light, and the laser light is irradiated. Cutting is performed while suppressing the extension of the cracks 30 by using the compressive stress (see FIG. 4) generated in the region. That is, the extension of the crack 30 is controlled using the compressive stress generated by the irradiation of the laser beam 20. As a result, it is possible to suppress the crack 30 from moving away from the planned cutting line.
  • ⁇ ⁇ t 2 is preferably close to 0 when the laser wavelength used is close to the wavelength region of visible light. However, since ⁇ ⁇ t 2 is too small, the absorption efficiency is deteriorated. Therefore, it is preferably 0.0005 or more (laser light absorption rate 0.05% or more), more preferably 0.002 or more (laser light absorption rate 0. 2% or more), more preferably 0.004 or more (laser light absorption rate 0.4% or more).
  • ⁇ ⁇ t 2 is preferably 3.0 or less (laser light absorptivity 95% or less), more preferably 0.1 or less (laser light absorptivity 10% or less), and further preferably 0.02 or less ( Laser light absorption rate is 2% or less).
  • the thickness t 2 (mm) of the tempered glass plate 10 is set according to the application, but is preferably 0.1 to 2.0 mm.
  • the internal residual tensile stress CT can be sufficiently increased by setting the thickness t 2 (mm) to 2.0 mm or less.
  • the thickness t 2 (mm) is less than 0.1 mm, it is difficult to subject the glass to chemical strengthening treatment.
  • the thickness t 2 (mm) is more preferably 0.3 to 1.5 mm, still more preferably 0.5 to 1.5 mm.
  • the absorption coefficient ⁇ is determined by the wavelength of the laser light 20, the glass composition of the tempered glass plate 10, and the like.
  • the absorption coefficient ⁇ in the near-infrared wavelength region near 1000 nm includes the content of iron oxide (including FeO, Fe 2 O 3 , and Fe 3 O 4 ) in the tempered glass plate 10, and cobalt oxide (CoO, Co 2 O). 3 and Co 3 O 4 ) and copper oxide (including CuO and Cu 2 O) are increased as the content increases. That is, by adjusting the content of iron oxide or the like, the value of ⁇ ⁇ t 2 can be adjusted to a desired range.
  • the content of iron oxide in the tempered glass plate 10 depends on the type of glass constituting the tempered glass plate 10, but in the case of soda lime glass, it is, for example, 0.02 to 1.0% by mass. However, as the content of iron oxide or the like increases, the transparency of the tempered glass plate 10 in the visible light region decreases.
  • the absorption coefficient ( ⁇ ) in the near-infrared wavelength region near 1000 nm is set according to the application.
  • the absorption coefficient ( ⁇ ) is preferably 0.3 mm ⁇ 1 or less.
  • the absorption coefficient ( ⁇ ) is preferably 0.06 mm ⁇ 1 or less.
  • the absorption coefficient ( ⁇ ) is preferably 0.02 mm ⁇ 1 or less.
  • the absorption coefficient ⁇ in the vicinity of the absorption wavelength of the rare earth atoms increases as the content of the rare earth element (for example, Yb) oxide in the tempered glass plate 10 increases.
  • the absorption coefficient ⁇ in the mid-infrared wavelength region near 3000 nm increases as the OH group content in the tempered glass plate 10 increases.
  • the OH group content does not affect the transparency in the visible light region.
  • the wavelength of the laser beam 20 may be 250 to 5000 nm, but is preferably 2500 to 3500 nm.
  • the wavelength of the laser light 20 is 2500 to 3500 nm (near 3000 nm), as described above, the absorption coefficient ⁇ can be increased without reducing the transparency in the visible light region. As a result, the heating efficiency by the laser beam 20 can be increased.
  • the wavelength of the laser beam 20 is more preferably 2700 to 3200 nm.
  • the absorptivity of the tempered glass plate having an iron oxide content of 0.04% by mass is about 2% when the plate thickness t 2 (mm) is 1 mm (transmittance: about 98). %). Therefore, the heating efficiency by laser light irradiation is poor. In addition, since the absorptance changes depending on the Fe concentration, it is necessary to significantly change the laser light irradiation conditions depending on the composition of the tempered glass plate.
  • the absorptivity of the tempered glass plate is about 50% (transmittance: about 50%) when the plate thickness is 1 mm regardless of the iron oxide content. . Therefore, the heating efficiency is improved as compared with the case where the wavelength is in the vicinity of 1000 nm, and it is not necessary to significantly change the irradiation condition of the laser beam by the composition of the tempered glass plate.
  • the wavelength is around 1000 nm and the absorptance is about 2%, for example, if 2 W of absorption power is required for cutting, 100 W is input and 98 W is transmitted. For this reason, if the table is positioned below the planned cutting line through which the laser beam passes, the table is damaged by the laser beam. Therefore, a device such as making the table one size smaller than the tempered glass panel cut out from the tempered glass plate is necessary. Further, it was necessary to process the transmitted laser beam. Furthermore, since the transmittance is high, the reflected light on the end face of the tempered glass plate may have an adverse effect.
  • the absorption rate of the laser beam is increased by the foreign matter adhering to the front surface or the back surface, the change in the absorption amount is large, which may have an adverse effect. Furthermore, even when the absorptance changes from 2% to 1% only by 1% due to the Fe concentration, it is necessary to change the input power from 100 W to 200 W by 100 W.
  • the wavelength is around 3000 nm and the absorptance is about 50%
  • 2W absorption power is required for cutting
  • 4W is input and 2W is transmitted.
  • the input power can be dramatically reduced and the heating efficiency can be improved.
  • the transmitted light also decreases dramatically, so that the table is not damaged even if the table is located below the planned cutting line through which the laser light passes. Therefore, it can cut
  • the power of the reflected light at the end face of the tempered glass plate is also small and hardly adversely affected. Further, even if the absorption rate of the laser beam is increased due to foreign matters adhering to the front surface or the back surface, the change in the amount of absorption is small and hardly adversely affected. Further, there is no change in the absorption rate due to the Fe concentration, and even if the absorption rate is reduced from 50% to 40% by 10%, the power to be input may be changed from 4W to 5W by 1W.
  • the tempered glass plate can be cut.
  • the cutting method of the tempered glass board concerning this Embodiment is demonstrated in detail.
  • the wavelength of about 3000 nm is preferable as the wavelength of the laser beam.
  • the tempered glass sheet cutting method described below is not limited to this wavelength.
  • the laser beam having a wavelength of 250 to 5000 nm is used. Can be widely applied about.
  • FIG. 6 is a diagram for explaining a method of cutting a strengthened glass sheet according to the present embodiment.
  • FIG. 6 is a view of the tempered glass plate 10 as viewed from above.
  • the broken line shown in the tempered glass board 10 has shown the cutting scheduled line 34 for cutting out the tempered glass panel 40 from the tempered glass board 10 using the cutting method demonstrated above.
  • the tempered glass panel 40 has a quadrangular shape having four corner portions C1, C2, C3, C4 having a predetermined radius of curvature R and straight portions 41, 42, 43, 44.
  • the shape of the tempered glass panel 40 shown in FIG. 6 is an example, and when the tempered glass panel 40 having any other shape is cut out from the tempered glass plate 10, the tempered glass cutting method according to the present embodiment is used. Can be used.
  • the laser beam is scanned so as to pass through the planned cutting line 34. Specifically, the scanning of the laser beam is started from the cutting start position 45 located on the end face on the extension of the linear portion 41. And the connection point of the corner part C4 and the straight part 41 via the straight part 41, the corner part C1, the straight part 42, the corner part C2, the straight part 43, the corner part C3, the straight part 44, and the corner part C4.
  • the laser beam is scanned up to the cutting end position 46.
  • initial cracks are formed in advance at the cutting start position 45, that is, at the end of the tempered glass plate 10.
  • the initial crack can be formed by, for example, a cutter, a file, or a laser.
  • the tempered glass panel 40 when the tempered glass panel 40 is cut out from the tempered glass plate 10 using laser light, it is necessary to optimize the conditions of the laser light applied to the tempered glass plate 10. That is, when the condition of the laser beam applied to the tempered glass plate 10 is inappropriate, the cutting line may deviate from the planned cutting line, and the tempered glass panel 40 that is cut out may be defective in dimensions.
  • the tempered glass panel 40 shown in FIG. 6 has four corner portions C1, C2, C3, and C4 having a predetermined radius of curvature R. Therefore, in order to cut efficiently (productivity), it is necessary to change the conditions of the irradiated laser light in the straight portions 41, 42, 43, and 44 and the corner portions C1, C2, C3, and C4.
  • the irradiation energy of the laser light per unit irradiation area irradiated on the tempered glass plate 10 is made larger at the corner portions C1, C2, C3, C4 than at the straight portions 41, 42, 43, 44. .
  • the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area is applied to the tempered glass plate 10 with the laser beam output P (W) and the laser beam scanning speed v (mm / s).
  • the beam diameter of the laser beam is ⁇ (mm)
  • E (J / mm 2 ) P (W) / (v (mm / s) ⁇ ⁇ (mm)) Equation 3
  • the irradiation energy E (J / mm 2 ) of the laser light per unit irradiation area is the energy per area where the laser light scans the tempered glass plate 10 per unit time (1 second).
  • the laser beam irradiation energy per unit irradiation area is also referred to as unit irradiation energy.
  • the unit irradiation energy E (J / mm 2 ) can be increased by slowing the moving speed (scanning speed) v (mm / s) of the laser light irradiation region. Further, the unit irradiation energy E (J / mm 2 ) can be increased by increasing the output P (W) of the laser beam. Further, the unit irradiation energy E (J / mm 2 ) can be increased by reducing the area (that is, the beam diameter ⁇ ) of the laser light irradiation region. Further, the unit irradiation energy E (J / mm 2 ) can be increased by appropriately combining these methods.
  • the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be decreased.
  • the absorption coefficient ⁇ is large, the energy absorbed by the tempered glass plate 10 increases, so that the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area can be reduced accordingly.
  • the irradiation energy E (J / mm 2 ) of the laser beam per unit irradiation area may be increased as the thickness t of the tempered glass plate increases.
  • the thickness t of the tempered glass plate is thick, it is necessary to increase the energy supplied to the tempered glass plate 10, so that the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be increased. preferable.
  • the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be reduced.
  • the thermal expansion coefficient of the tempered glass plate 10 is large, the tensile stress generated behind the scanning direction of the laser beam increases, and accordingly, the irradiation energy E (J / mm 2 ) of the laser beam per unit irradiation area is reduced accordingly. be able to.
  • the unit irradiation energy of the laser light irradiated at the straight portions 41, 42, 43, 44 is E1
  • the unit irradiation energy of the laser light irradiated at the corner portions C1, C2, C3, C4 is E2 larger than E1.
  • the unit irradiation energy is switched from E1 to E2 when moving from the straight line portion 41 to the corner portion C1.
  • the unit irradiation energy is switched from E2 to E1.
  • the unit irradiation energy is switched from E1 to E2 when shifting from the straight line portion 42 to the corner portion C2, and the unit irradiation energy is switched from E2 to E1 when shifting from the corner portion C2 to the straight line portion 43.
  • the unit irradiation energy is switched from E1 to E2 when shifting from the straight line portion 43 to the corner portion C3, and the unit irradiation energy is switched from E2 to E1 when shifting from the corner portion C3 to the straight line portion 44. Then, when shifting from the straight line portion 44 to the corner portion C4, the unit irradiation energy is switched from E1 to E2.
  • switching of the unit irradiation energies E1 and E2 is preferably performed in as short a time as possible in view of productivity.
  • the cutting line is outside the planned cutting line 34.
  • the present inventors have found that the tempered glass panel 40 that protrudes and cuts out may be defective in dimensions.
  • the inventor suppresses the deviation amount (that is, dimensional error) from the planned cutting line 34 by restricting (lowering) the switching speed of the unit irradiation energy at the transition point from the corner portion to the straight portion.
  • FIG. 7 is a graph schematically showing switching of the unit irradiation energy E between the straight line portion and the corner portion.
  • the horizontal axis represents time, and the vertical axis represents unit irradiation energy E (J / mm 2 ).
  • the unit irradiation energy switching speed at this point is preferably as fast as possible. . Therefore, in the method for cutting tempered glass according to the present embodiment, the unit irradiation energy switching speed at the corner portion outlet is set to be lower than the unit irradiation energy switching speed at the corner portion entrance. Further, as indicated by a solid line in the graph of FIG. 7, it is preferable that the switching speed ⁇ E / T of the unit irradiation energy at the exit of the corner portion is changed as smoothly as possible (gradual increase) rather than being constant. . Thereby, the deviation
  • the inventor has found that the switching speed of the unit irradiation energy needs to be kept lower as the residual tensile stress CT of the tempered glass plate 10 is smaller. Therefore, in the method for cutting tempered glass according to the present embodiment, the unit irradiation energy switching speed is kept lower as the residual tensile stress CT of the tempered glass plate 10 is smaller.
  • FIG. 8 is a table showing the cutting results for the tempered glass sheet.
  • FIG. 9 is a table showing the cutting results for the non-tempered glass sheet.
  • FIG. 10 is a table showing cutting results for a tempered glass plate (reference example) and a non-tempered glass plate (comparative example). The cutting results shown in FIG. 10 are cutting results when the spot diameter of the laser beam is made smaller than the cutting results shown in FIGS.
  • a tempered glass plate was prepared, and in Comparative Examples 104 to 105 and 109 to 110, a non-tempered glass plate was prepared.
  • the tempered glass plates of Reference Examples 101 to 103 and 106 to 108 have the same size and shape as the non-tempered glass plates of Comparative Examples 104 to 105 and 109 to 110 (rectangle, long side 100 mm, short side 60 mm, plate thickness 0.7 mm).
  • a glass plate having the same chemical composition was reinforced by a chemical strengthening method.
  • the tempered glass plate had an internal residual tensile stress (CT) of 30.4 MPa, a maximum residual compressive stress (CS) of 763 MPa, and a thickness (DOL) of the compressive stress layer (surface layer or back surface layer) of 25.8 ⁇ m.
  • CT internal residual tensile stress
  • CS maximum residual compressive stress
  • DOL thickness of the compressive stress layer (surface layer or back surface layer) of 25.8 ⁇ m.
  • the internal strain energy U CT was 4.04 J / m 2 .
  • Laser light source Fiber laser (wavelength 1070 nm) Incident angle of laser beam to glass plate: 0 ° Condensing angle of laser beam: 2.5 ° Laser beam condensing position: position 23 mm away from the surface of the glass plate toward the light source side Laser spot diameter on the surface of the glass plate: ⁇ 1 mm Absorption coefficient ⁇ of the glass plate with respect to laser light: 0.09 cm ⁇ 1 (0.009 mm ⁇ 1 ) Thickness t of glass plate: 0.07 cm (0.7 mm) Young's modulus Y of glass plate: 74000 MPa ⁇ ⁇ t: 0.0063 Nozzle outlet diameter: ⁇ 1mm Flow rate of cooling gas (room temperature compressed air) from the nozzle: 30 L / min Target cutting position: A straight line parallel to the short side of the glass plate (distance 10 mm from one short side, distance 90 mm from the other short side) Cutting speed: 2.5 mm / s
  • the cut surface of the glass plate was observed with a microscope.
  • the striped pattern observed on the cut surface of the glass plate represents a change with time of the tip position of the intermittently extending crack. From the shape of each striped line, you can see how the cracks extend. In the micrographs shown in FIGS. 8 to 10, representative lines of the stripe pattern are highlighted with thick white lines. Moreover, the state of the crack when laser irradiation and gas cooling were interrupted during the cutting of the glass plate was visually observed.
  • FIGS. 8 to 10 The results of each experiment are shown in FIGS. 8 to 10, the case where a crack was formed on the glass plate (when it was cut) was shown as “ ⁇ ”, and the case where no crack was formed on the glass plate (when it was not cut) was shown as “x”. .
  • the striped line in the micrographs of the cut planes of FIGS. 8 to 10 represents the tip position of the crack at a certain point. “Self-propelled” in FIGS. 8 to 10 means that, after interruption of laser irradiation or the like, the crack extends toward the shorter side closer to the cutting position among the two shorter sides of the glass plate.
  • the convex amount and the straight line error amount indicate the error amount when the glass plate is cut. That is, it shows the amount (indicated by the Y axis of the graph) that the cutting line of the glass plate deviates from the planned cutting line (indicated by the X axis of the graph) when the glass plate is viewed from the upper surface side.
  • the tempered glass plate when the laser spot diameter was reduced (Reference Examples 106 to 108), the tempered glass plate could be cut with a light source output smaller than that of Reference Examples 101 to 103. Further, in Reference Examples 106 to 108, the convex amount and the linear error amount were smaller than those in Reference Examples 101 to 103 shown in FIG. That is, in Reference Examples 106 to 108, the tempered glass plate could be cut with higher accuracy than Reference Examples 101 to 103. Further, as shown in Reference Examples 106 to 108, as the light source output was lowered, the convex amount and the linear error amount were reduced. Particularly in Reference Example 108, the convex amount was as small as 15 ⁇ m.
  • the non-tempered glass plate could not be cut. That is, as shown in Comparative Example 109, when the output of the light source was 200 W, the non-tempered glass plate was melted and could not be cut. That is, the temperature of the non-tempered glass was not lower than the annealing point and could not be cut. Further, as shown in Comparative Example 110, when the output of the light source was 100 W, there was no change in the non-tempered glass plate. Therefore, when the laser spot diameter was reduced (for example, less than the plate thickness), the non-tempered glass plate could not be cut regardless of the output of the light source.
  • the cutting mechanism is fundamentally different between the method of cutting a tempered glass plate and the method of cutting a non-tempered glass plate, and the method of extending cracks is completely different. Therefore, in this invention, the effect which cannot be estimated from the cutting method of a non-tempered glass board is acquired. The reason will be described below.
  • a thermal stress field is formed on the glass plate using both a laser beam and a cooling liquid to generate a tensile stress necessary for cutting. More specifically, the glass plate is irradiated with laser light to generate thermal stress inside the glass plate, and the compressive stress generated by the thermal stress is quenched with a cooling liquid to generate tensile stress and extend cracks. Let Therefore, the extension of the crack is performed only by the irradiation energy of the laser beam, and it is necessary to set a large power (W) of the laser irradiated to the glass plate.
  • W large power
  • the tip position of the cleaving crack formed in the glass plate is determined by the position of the coolant that cools the glass plate. This is because tensile stress is generated at the position of the coolant. Therefore, if heating with laser light or cooling with a coolant is interrupted during cutting, the extension of cracks stops.
  • FIG. 11 is a diagram for explaining the stress that acts when cutting a non-tempered glass plate using a laser beam.
  • FIG. 11 shows a top view of the non-tempered glass plate 110 and a distribution of stress generated at the center of the thickness of the non-tempered glass plate 110.
  • a compressive stress 133 acts on the laser light irradiation region 122.
  • This compressive stress 133 is a thermal stress generated by laser light irradiation.
  • a tensile stress 135 is generated behind the irradiation region 122 in the scanning direction so as to balance with the compressive stress 133.
  • the non-tempered glass plate 110 is cut by the tensile stress 135 acting on the crack 130.
  • the internal residual tensile stress CT is substantially zero.
  • the tensile stress 135 which acts on the crack 130 when cutting the non-tempered glass plate 110 is generated only by laser light irradiation. Therefore, in order to increase the tensile stress 135, it is necessary to increase the irradiation energy of the laser beam or increase the laser spot diameter. For this reason, in the non-tempered glass plate 110, it becomes difficult to cut with glass having a low absorption rate of laser light.
  • the extension of cracks is controlled by the irradiation energy of the laser beam and the scanning speed. At this time, if the irradiation energy of the laser beam is smaller than the irradiation energy necessary for cutting, the extension of the crack is stopped. That is, as shown in the graph of FIG. 11, in order to extend the crack 130, it is necessary to apply a tensile stress larger than the tensile stress S_th necessary for the extension of the crack 130 to the crack 130. Since the internal residual tensile stress CT is substantially zero in the non-tempered glass plate 110, it is necessary to generate a tensile stress larger than the value of the tensile stress S_th only with the laser beam irradiation energy.
  • a tensile stress smaller than the value of the internal residual tensile stress or a compressive stress is generated in the intermediate layer at the center of the irradiation region, thereby suppressing the extension of cracks due to the internal residual tensile stress. That is, the extension of the crack is controlled by irradiating the laser beam so that the residual tensile stress in the intermediate layer of the tempered glass plate is made smaller than the tensile stress S_th necessary for the extension of the crack.
  • FIG. 12 is a diagram showing an example of stress acting when a tempered glass plate is cut using a laser beam.
  • FIG. 12 shows a top view of the tempered glass plate 10 and a distribution of stresses generated at the central portion of the thickness of the tempered glass plate 10.
  • a compressive stress 33 acts on the laser light irradiation region 22.
  • a tensile stress 35 is generated behind the irradiation region 22 in the scanning direction.
  • the internal residual tensile stress is added to the tensile stress 35 to generate a tensile stress larger than the tensile stress S_th necessary for the extension of the crack, and the tempered glass sheet 10 is cut by acting on the crack 30. .
  • extension of the crack 30 is controlled by the compressive stress 33.
  • the tempered glass plate 10 has an internal residual tensile stress CT. For this reason, the tensile stress 35 required for the extension of the crack 30 can be small. In other words, it is possible to reduce the compressive stress 33 generated by the laser beam necessary for causing the tensile stress larger than the tensile stress S_th (the tensile stress necessary for the extension of the crack 30) to act on the crack 30.
  • the compressive stress 33 and the tensile stress 35 required when cutting the tempered glass plate 10 can be made smaller than the stress required when cutting the non-tempered glass 110, the irradiation energy of the laser beam is reduced.
  • the laser spot diameter can be reduced or the laser spot diameter can be reduced. For this reason, cutting accuracy can be improved. Further, even glass having a low absorption rate of laser light can be easily cut.
  • FIG. 13 is a diagram showing another example of stress acting when a tempered glass plate is cut using a laser beam.
  • FIG. 13 shows a top view of the tempered glass plate 10 and a distribution of stresses generated at the central portion of the thickness of the tempered glass plate 10.
  • the internal residual tensile stress CT is larger than the tensile stress S_th necessary for the extension of the crack 30. That is, as shown in FIG. 13, when the tempered glass plate 10 is irradiated with laser light, a tensile stress 37 smaller than the value of the internal residual tensile stress CT is generated in the laser light irradiation region 22.
  • the tensile stress 37 is a resultant force of the compressive stress 33 generated by the laser light irradiation and the internal residual tensile stress CT. Further, a tensile stress 35 is generated behind the irradiation region 22 in the scanning direction. In this case, the extension of the crack 30 can be suppressed by making the tensile stress 37 smaller than the value of the internal residual tensile stress CT smaller than the tensile stress S_th necessary for the extension of the crack 30.
  • the tensile stress 37 and the tensile stress 35 smaller than the value of the internal residual tensile stress CT required when cutting the tempered glass plate 10 are stresses required when cutting the non-tempered glass 110. Therefore, the irradiation energy of laser light can be reduced, and the laser spot diameter can be reduced. For this reason, cutting accuracy can be improved. Further, even glass having a low absorption rate of laser light can be easily cut.
  • the extension of the crack 30 without causing the crack 30 to self-run. Is controlling. Therefore, if the laser beam irradiation energy is too small, the tensile stress 37 smaller than the value of the internal residual tensile stress CT becomes larger than the tensile stress S_th required for the extension of the crack 30, and the extension of the crack 30 does not stop. Run (in the case of FIG. 13).
  • the cutting mechanism is fundamentally different between the method of cutting a tempered glass plate and the method of cutting a non-tempered glass plate, and the method of extending cracks is completely different. Therefore, in this invention, the effect which cannot be estimated from the cutting method of a non-tempered glass board is acquired.
  • a glass raw material prepared by mixing a plurality of types of raw materials was melted, and the melted molten glass was formed into a plate shape. This was gradually cooled to near room temperature, and then cut, cut, and polished on both sides to prepare a 50 mm ⁇ 50 mm glass plate having a predetermined thickness.
  • the glass raw material was prepared by changing the amount of iron oxide (Fe 2 O 3 ) powder added to the base material having the same blending ratio so that the absorption coefficient ⁇ of the glass plate with respect to the laser beam became a desired value.
  • Each glass sheet for chemical strengthening is expressed in terms of mass% based on oxide, SiO 2 : 60.9%, Al 2 O 3 : 12.8%, Na 2 O: 12.2%, K 2 O: 5. 9%, MgO: 6.7%, CaO: 0.1%, SrO: 0.2%, BaO: 0.2%, ZrO 2 : 1.0%, and iron oxide (Fe 2 O 3 ) was contained in a predetermined amount by external division.
  • Each tempered glass plate was prepared by immersing the above-described glass plate for chemical strengthening in KNO 3 molten salt, performing an ion exchange treatment, and then cooling to near room temperature.
  • the treatment conditions such as the temperature and immersion time of the KNO 3 molten salt were set so that the internal residual tensile stress CT had a desired value.
  • the internal residual tensile stress CT (MPa) of the tempered glass plate was measured using a surface stress meter FSM-6000 (manufactured by Orihara Seisakusho) and the surface compressive stress CS (MPa) and the thickness DOL (surface layer and back layer) [mu] m) was measured, and the measured values were calculated using equation 1 below color and thickness t 1 ([mu] m) of the tempered glass sheet.
  • CT (CS ⁇ DOL) / (t 1 ⁇ 2 ⁇ DOL) Equation 1
  • the internal strain energy U CT (J / m 2 ) was determined by the following formula 2 using the Young's modulus Y (MPa) of the tempered glass plate.
  • U CT ⁇ CT 2 ⁇ (t 1 ⁇ 2 ⁇ DOL) ⁇ / (2 ⁇ Y) Equation 2
  • the laser beam irradiation energy per unit irradiation area is defined as Pe (W), the effective laser output incident without being reflected on the tempered glass plate, v (mm / s) as the laser beam scanning speed, and the tempered glass plate. 10 is represented by Pe / (v ⁇ ⁇ ) (unit: J / mm 2 ).
  • Pe / (v ⁇ ⁇ ) unit: J / mm 2 .
  • E L (J / mm) the irradiation energy of the laser light per unit length obtained by multiplying this by the beam diameter ⁇ (mm). The detailed reason will be described later.
  • This irradiation energy E L (J / mm) is shown in Equation 4 below.
  • E L Pe / v Equation 4
  • the critical irradiation energy Ec which is the critical value of the irradiation energy E L for the samples 1 to 11, was obtained by changing the irradiation energy E L by about 1 (J / mm) and repeating the cutting. At that time, only the laser output P (W) was changed by 2.5 W while the scanning speed v (mm / s) of the laser beam was fixed.
  • the critical irradiation energy Ec for samples 18-21 unreinforced glass plates was determined by repeating the cutting by changing the irradiation energy E L by about 4 (J / mm). At that time, only the laser output P (W) was changed by 10 W while the scanning speed v (mm / s) of the laser beam was fixed. On the other hand, the critical irradiation energy Ec of the samples 12 to 17 was determined by repeating the cutting is gradually changed the irradiation energy E L. At that time, only the scanning speed v (mm / s) of the laser beam was changed by 0.25 mm / s while the laser output P (W) was fixed.
  • FIG. 15 is a table showing the laser wavelength ⁇ , the internal strain energy U CT , the critical irradiation energy Ec, and various conditions for deriving both of the samples 1 to 21.
  • a fiber laser (center wavelength band: 1070 nm) is used as the laser light source, and for samples 12 to 17, the mid-infrared is used as the laser light source.
  • a Cr: ZnSe laser (central wavelength band: 2950 nm) using an optical parametric oscillator was used.
  • air having a flow rate of 15 L / min was blown from the laser light irradiation side using a nozzle having a diameter of 1 mm ⁇ .
  • the distance (gap) between the tempered glass plate and the nozzle tip was 3 mm.
  • FIG. 16A is a graph showing the internal strain energy U CT dependence of the critical irradiation energy Ec shown in the table of FIG.
  • the horizontal axis of FIG. 16A is internal strain energy U CT (J / m 2 ), and the vertical axis is critical irradiation energy Ec (J / mm).
  • the critical irradiation energy Ec 65 J / mm. That is, as the beam diameter increased, the critical irradiation energy Ec gradually decreased.
  • the beam diameter ⁇ is preferably not more than the plate thickness t, and more preferably not more than 1 ⁇ 2 of the plate thickness t.
  • the absorption coefficient ⁇ can be increased without lowering the transparency, and the irradiation energy can be reduced. Therefore, the heating efficiency is improved.
  • tempered glass can be mounted on a table larger than the tempered glass board to cut
  • the energy used for cutting is energy (hereinafter referred to as critical absorption energy) Ea absorbed by the tempered glass plate.
  • the critical absorption energy Ea (J / mm) is calculated from the Lambert-Beer law using the following equation using the critical irradiation energy Ec (J / mm), the absorption coefficient ⁇ (mm ⁇ 1 ), and the thickness t 2 (mm): Can be represented.
  • Ea Ec ⁇ exp ( ⁇ ⁇ t 2 ) Equation 5
  • the thermal stress (critical compressive stress) ⁇ c generated by internal heating (temperature change ⁇ T) at the critical absorption energy Ea will be considered.
  • This critical compressive stress ⁇ c is the minimum compressive stress necessary for cutting.
  • the critical compressive stress ⁇ c is expressed as “critical compressive stress” because it becomes a compressive stress when the internal residual tensile stress CT is used as a reference.
  • FIGS. 12 and 13 when considering the stress generated at the center of the thickness of the tempered glass plate, it is expressed by the resultant force of the internal residual tensile stress CT and the critical compressive stress ⁇ c. It may become.
  • the critical compressive stress ⁇ c has a Gaussian distribution-like profile as shown in FIGS.
  • the integral value of this critical compressive stress ⁇ c determines whether cutting is possible. If the internal strain energy U CT is the same, the integral value of the critical compressive stress ⁇ c is considered to be constant regardless of the thickness t and the material of the tempered glass sheet. Since the width of the profile of the critical compressive stress ⁇ c is proportional to the beam diameter ⁇ , it can be considered that the integrated value of the critical compressive stress ⁇ c is also proportional to ⁇ c ⁇ ⁇ .
  • the plate thickness t of the tempered glass plate does not change even by internal heating, and this critical compressive stress ⁇ c is generated by being constrained between the front surface layer 13 and the back surface layer 15.
  • the critical compressive stress ⁇ c (MPa) can be expressed by the following formula 6 using the Young's modulus Y (MPa), the linear expansion coefficient ⁇ L (K ⁇ 1 ), and the temperature change ⁇ T (K).
  • ⁇ c Y ⁇ ⁇ L ⁇ ⁇ T Equation 6
  • ⁇ T (critical absorption energy) / (heat capacity of the tempered glass plate of the laser irradiation portion).
  • the laser irradiation area S 1 (mm 2 ) (critical absorption energy) is critical absorption energy Ea / ⁇ per unit area obtained by dividing critical absorption energy Ea (J / mm) by ⁇ (mm).
  • J / mm 2 it can be expressed as Ea ⁇ S 1 / ⁇ (J).
  • the area S 2 (mm 2 ) of the heating region in the tempered glass plate, (the heat capacity of the tempered glass plate of the laser irradiation part) is the thickness t 2 (mm) of the tempered glass plate, and the density ⁇ (g / mm). 3 ), and can be expressed as S 2 ⁇ t 2 ⁇ ⁇ ⁇ c (J / K) using specific heat c (J / g / K).
  • Equation 8 the critical compressive stress ⁇ c (MPa)
  • Equation 9 Kc Equation 9 Kc in Equation 9 is named the critical cutting index.
  • the cutting property can be determined by the irradiation energy E L (J / mm) of the laser beam per unit length expressed by the equation 4.
  • the Young's modulus Y, linear expansion coefficient ⁇ L , density ⁇ , and specific heat c constituting the critical cutting index Kc all have temperature dependence, but room temperature values are used as indices only.
  • the critical cutting index Kc (N / mm) is shown in the rightmost column of FIG.
  • FIG. 16B is a graph showing the internal strain energy U CT dependence of the critical cutting index Kc shown in the table of FIG.
  • the horizontal axis in FIG. 16B is the internal strain energy U CT (J / m 2 ), and the vertical axis is the critical cutting index Kc (N / mm).
  • the critical cutting index Kc 150 N / mm (sample 16) or exceeds 200 N / mm (samples 11 and 17).
  • the non-tempered glass plate exceeds 250 N / mm (samples 18 to 21).
  • the critical cutting index Kc becomes larger, and when the beam diameter is 0.5 mm or less, cutting becomes impossible (sample 18).
  • the beam diameter ⁇ preferably set to less thickness t 2 (mm), and even more preferably to a half or less of the plate thickness t 2 (mm).
  • K E L ⁇ exp ( ⁇ ⁇ t 2 ) ⁇ (Y ⁇ ⁇ L ) / (t 2 ⁇ ⁇ ⁇ c) Equation 10
  • Expression 4 Pe / v ⁇ exp ( ⁇ ⁇ t 2 ) ⁇ (Y ⁇ ⁇ L ) / (t 2 ⁇ ⁇ ⁇ c).
  • the critical cutting index Kc is about 50 N / mm, so that sufficient cutting can be performed with the irradiation energy E L satisfying the cutting index K ⁇ 150 N / mm. it can.
  • the critical cutting index Kc is 150 N / mm or more. Therefore, in the irradiation energy E L that satisfies the cutting index K ⁇ 150 N / mm, Cutting becomes impossible or difficult.
  • Example 1 the relationship between the amount of change in unit irradiation energy per unit time and the amount of deviation (dimension error) from the design dimension will be described.
  • Example 1 a tempered glass plate (sample A) having a plate thickness of 1.1 mm, a surface compressive stress CS of 756 MPa, a thickness DOL of each of the surface layer and the back layer of 30.5 ⁇ m, and a residual tensile stress CT of 22 MPa, A tempered glass plate (sample B) having a plate thickness of 1.1 mm, a surface compressive stress CS of 716 MPa, a thickness DOL of each of the front surface layer and the back surface layer of 68.8 ⁇ m, and a residual tensile stress CT of 51 MPa was used.
  • FIG. 17 shows the shape of the cut-out tempered glass panel.
  • the length L is 50 mm
  • the width W is 35 mm
  • the curvature radius R of the corner portion is 5 mm.
  • widths W1 and W3 in the vicinity of the boundary between the corner portion and the straight portion, width W2 in the central portion in the longitudinal direction, lengths L1 and L3 in the vicinity of the boundary between the corner portion and the straight portion, and the center in the width direction A total of six dimensions of the part length L2 were measured using calipers. Then, a dimensional error ⁇ was calculated for each dimension.
  • the residual tensile stress CT of the tempered glass plate is measured by measuring the surface compressive stress CS and the thickness DOL of the compressive stress layer (surface layer and back layer) with a surface stress meter FSM-6000 (manufactured by Orihara Seisakusho). From the thickness t of the tempered glass plate, calculation was performed using Equation 1.
  • the tempered glass plate was cut by the cutting method described with reference to FIG. An initial crack was formed in advance at the cutting start position at the end of the tempered glass plate, and no scribe line was formed on the surface of the tempered glass plate.
  • the light source of the laser light was a fiber laser (central wavelength band: 1070 nm).
  • FIG. 18 is a table showing cutting conditions for the tempered glass sheet.
  • the conditions for cutting A1 to A4 (sample A) and B1 to B4 (sample B) are shown.
  • the numerical values shown in the table of FIG. 18 will be described in order from the left column.
  • the laser output P was 100 W for all of samples A1 to A4, and 80 W for all of samples B1 to B4.
  • the beam diameter ⁇ was 0.1 mm for all samples.
  • the scanning speed v (mm / s) of the laser beam at the straight line portion and the corner portion was 5 mm / s and 1 mm / s for all the samples, respectively. Therefore, the scanning speed change amount ⁇ v (mm / s) between the straight line portion and the corner portion is 4 mm / s for all the samples.
  • Example 1 in order to change the unit irradiation energy change amount ⁇ E / T (J / mm 2 / s) per unit time, the acceleration a (mm / s 2 ) of the scanning speed at the corner exit is changed. It was. As shown in FIG. 18, the samples A1 ⁇ A4 is to acceleration a the (mm / s 2), respectively 1,3,5,20mm / s 2, for the samples B1 ⁇ B4 are acceleration a (mm / s 2 ) Was set to 1, 3, 5, 10 mm / s 2 , respectively.
  • the scanning speed switching time T (s) at the corner exit was obtained by dividing the scanning speed change ⁇ v (mm / s) by the acceleration a (mm / s 2 ).
  • the unit irradiation energy E (J / mm 2 ) was obtained by substituting the laser output P (W), the laser beam scanning speed v (mm / s), and the beam diameter ⁇ (mm) into the above Equation 3. .
  • the unit irradiation energy E in the linear portion (J / mm 2) for example A1 ⁇ A4 are all 200 J / mm 2, for the samples B1 ⁇ B4 are all became 160 J / mm 2.
  • the unit irradiation energy E (J / mm 2) is at the corner portion, the samples A1 ⁇ A4 are all 1000 J / mm 2, for the samples B1 ⁇ B4 are all became 800 J / mm 2.
  • the linear unit and the unit irradiation energy amount of change in a corner portion ⁇ E (J / mm 2), for example A1 ⁇ A4 are all 800 J / mm 2, for the samples B1 ⁇ B4 are all 640J / mm 2
  • the unit irradiation energy change amount ⁇ E / T (J / mm 2 / s) per unit time was obtained by dividing the unit irradiation energy change amount ⁇ E (J / mm 2 ) by the switching time T (s).
  • the samples A1 to A4 are 200, 600, 1000, and 4000 J / mm 2 / s, respectively, and the samples B1 to B4 are 160, 480, 800, and 1600 J / mm 2 / s, respectively. became.
  • the acceleration of the scanning velocity at the corner portion inlet was -100 mm / s 2 (i.e., deceleration 100mm / s 2).
  • air having a flow rate of 15 L / min was blown from the laser light irradiation side using a nozzle having a diameter of 1 mm ⁇ .
  • the distance (gap) between the tempered glass plate and the nozzle tip was 2 mm.
  • FIG. 19 is a cross-sectional view of the cooling nozzle used in the method for cutting a strengthened glass sheet according to Example 1.
  • a gas is blown onto the surface 12 of the tempered glass plate 10 by the cooling nozzle 28 shown in FIG.
  • the cooling nozzle 28 has a tapered cavity so that gas (air, nitrogen, etc.) flows in the direction of the arrow.
  • the axis of the cooling nozzle 28 coincides with the optical axis of the laser beam, and the laser beam 20 collected by the lens 25 passes through the inside of the cooling nozzle 28 and is provided at the tip of the cooling nozzle 28.
  • the light is emitted from an opening having a diameter ⁇ n.
  • the laser irradiation part irradiation region 22 of the laser light 20
  • the gas is cooled by the gas.
  • the diameter ⁇ n of the opening of the cooling nozzle 28 and the distance G1 between the tip of the cooling nozzle 28 and the surface 12 of the tempered glass plate 10 can be arbitrarily determined.
  • the diameter ⁇ n of the opening of the cooling nozzle 28 is smaller, the flow rate of the gas blown to the tempered glass plate 10 becomes faster, and the cooling capacity on the surface 12 of the tempered glass plate 10 is improved.
  • the cooling capability in the surface 12 of the tempered glass board 10 improves, so that the distance G1 of the front-end
  • air at a flow rate of 15 L / min was sprayed at four corners C1 to C4 using nozzles with a diameter of 1 mm ⁇ fixed from the back surface 14 side of the tempered glass plate 10 respectively.
  • FIG. 20 is a table showing the cutting results of the tempered glass sheet.
  • the table of FIG. 20 shows the change amount ⁇ E / T (J / mm 2 / s) of unit irradiation energy per unit time of each sample and the dimensional error of the tempered glass panel cut out from each sample. .
  • the sample number the change amount ⁇ E / T (J / mm 2 / s) of the unit irradiation energy, the minimum value ⁇ Wmin (mm) of the dimensional error of the width (W1 to W3), Dimension error maximum value ⁇ Wmax (mm) of width (W1 to W3), dimensional error minimum value ⁇ Lmin (mm) of length (L1 to L3), dimensional error maximum value ⁇ Lmax (length (L1 to L3)) mm), dimensional error width ⁇ (mm), maximum dimensional error ⁇ max (mm), dimensional error of width (W1 to W3) and average value ⁇ avg (mm) of dimensional error of length (L1 to L3) are shown. Yes.
  • FIG. 21 is a graph showing the dependency ⁇ E / T dependency of the unit irradiation energy per unit time of the maximum value ⁇ max of the dimensional error.
  • the horizontal axis indicates the change amount ⁇ E / T (J / mm 2 / s) of the unit irradiation energy
  • the vertical axis indicates the maximum value ⁇ max (mm) of the dimensional error.
  • the change amount ⁇ E / T of unit irradiation energy per unit time is 200 J / mm 2 / s or less. do it.
  • the change amount ⁇ E / T of the unit irradiation energy per unit time may be 800 J / mm 2 / s or less.
  • FIG. 22 is a diagram for explaining the tempered glass sheet cutting device according to the present embodiment.
  • the tempered glass sheet cutting device 60 according to the present embodiment includes a laser output unit 61, a glass holding unit 62, a control unit 63, and a control program generation unit 64.
  • the laser output unit 61 outputs a laser beam 20 for cutting the tempered glass plate 10.
  • Examples of the light source of the laser beam 20 include a UV laser (wavelength: 355 nm), a green laser (wavelength: 532 nm), a semiconductor laser (wavelength: 808 nm, 940 nm, 975 nm), a fiber laser (wavelength: 1060 to 1100 nm), and a YAG laser. (Wavelength: 1064 nm, 2080 nm, 2940 nm) or the like can be used.
  • the laser output unit 61 includes an optical system for adjusting the focus of the laser light. Further, a nozzle may be arranged in the laser light irradiation part. The power of the laser beam (laser output), the beam diameter (focal point) of the laser beam, the timing of laser irradiation, and the like are controlled using the control unit 63.
  • a mid-infrared laser having a wavelength of 2500 to 5000 nm may be used as the light source of the laser light 20. In the wavelength range of 2500 to 5000 nm, absorption due to molecular vibration of the glass itself occurs, so that it is not necessary to add impurities such as Fe.
  • the glass holding unit 62 holds the tempered glass plate 10 to be processed and moves the tempered glass plate 10 in a predetermined direction. In other words, the glass holding unit 62 moves the tempered glass plate 10 so that the laser beam scans the planned cutting line of the tempered glass plate 10.
  • the glass holding unit 62 is controlled using the control unit 63.
  • the glass holding part 62 may be fixed by adsorbing the tempered glass plate 10 to be processed using a porous plate or the like.
  • the glass holding unit 62 may include an image detector for determining the position of the tempered glass plate 10. By providing the image detector for positioning, the processing accuracy of the tempered glass plate 10 can be improved.
  • the tempered glass sheet 10 is moved using the glass holding part 62 so that the irradiation region of the laser beam 20 moves on the tempered glass sheet 10.
  • the laser output unit 61 is fixed.
  • the irradiation region of the laser beam 20 may be moved on the tempered glass plate 10 by fixing the tempered glass plate 10 held by the glass holding unit 62 and moving the laser output unit 61.
  • the control unit 63 controls the laser output unit 61 and the glass holding unit 62 based on the control program generated by the control program generation unit 64.
  • the control program generation unit 64 corresponds to preset physical properties of the tempered glass plate 10 (thermal expansion coefficient, thickness, absorption coefficient of the tempered glass plate with respect to laser light, residual tensile stress of the intermediate layer 17 of the tempered glass plate, etc.). Then, unit irradiation energies E1 and E2 that are applied to the tempered glass plate when the straight part and the corner part are cut are determined. And the control program which controls the beam diameter of a laser beam, the output of a laser beam, and the scanning speed of a laser beam is produced
  • the control program generation unit 64 generates a control program for controlling the switching speed from the unit irradiation energy E1 to E2 at the corner entrance and the switching speed from the unit irradiation energy E2 to E1 at the corner exit. To do. That is, the laser output unit 61 and the glass holding unit 62 are configured such that the switching speed from the unit irradiation energy E2 to E1 at the corner portion outlet is smaller than the switching speed from the unit irradiation energy E1 to E2 at the corner portion entrance.
  • a control program for controlling the system is generated. Specifically, in order to control the switching speed of the unit irradiation energy, a control program for controlling the switching speed such as the beam diameter of the laser light, the output of the laser light, and the scanning speed of the laser light is generated.

Abstract

In a method for cutting toughened glass plates in one embodiment of the present invention, if a cutting line on a toughened glass plate includes a corner section and a straight section, the amount of laser-light energy (E1) to which the toughened glass plate is exposed per unit area in the straight section is set higher than the amount of laser-light energy (E2) to which the toughened glass plate is exposed per unit area in the corner section. Also, the speed at which the switch is made from the corner-section energy level (E2) to the straight-section energy level (E1) is set lower than the speed at which the switch is made from the straight-section energy level (E1) to the corner-section energy level (E2).

Description

強化ガラス板の切断方法、及び強化ガラス板切断装置Method of cutting tempered glass sheet and tempered glass sheet cutting device
　本発明は強化ガラス板の切断方法、及び強化ガラス板切断装置に関し、特にレーザ光による内部加熱を利用した強化ガラス板の切断方法、及び強化ガラス板切断装置に関する。 The present invention relates to a method for cutting a tempered glass plate and a tempered glass plate cutting device, and more particularly to a method for cutting a tempered glass plate using internal heating by a laser beam and a tempered glass plate cutting device.
　携帯電話や携帯情報端末（ＰＤＡ：Personal Data Assistance）などの携帯機器では、ディスプレイのカバーや基板にガラス板が使用されている。携帯機器における薄型化・軽量化の要求から、ガラス板についても強度の高い強化ガラス板を用いることにより、薄型化・軽量化が図られるようになってきた。 In a portable device such as a mobile phone or a personal information terminal (PDA), a glass plate is used as a display cover or a substrate. Due to demands for thinning and weight reduction in portable devices, thinning and weight reduction have been achieved by using high strength tempered glass plates.
　ところで、ガラス板の切断は、通常、ダイヤモンド等の硬質のローラやチップにより、主面に機械的にスクライブ線を導入し、当該スクライブ線に沿って折曲力を加えることによりなされる。このような手法では、スクライブ線の導入により、ガラス板の切断端面に多数の微細クラックが生成されることになる。従って、強化ガラス板であるにもかかわらず、切断端部に充分な強度が得られないという問題があった。 Incidentally, the cutting of the glass plate is usually performed by introducing a scribe line mechanically into the main surface with a hard roller or chip such as diamond and applying a bending force along the scribe line. In such a technique, a lot of fine cracks are generated on the cut end face of the glass plate by introducing the scribe line. Accordingly, there is a problem that a sufficient strength cannot be obtained at the cut end despite the tempered glass plate.
　このような問題に対し、近年、レーザ光により強化ガラス板の内部を加熱し、強化ガラス板の主面でなく端面に導入した初期クラックの伸展を制御することにより、強化ガラス板を切断する方法が開発された。このようなレーザ光を用いた切断では、従来のように、強化ガラス板の主面にスクライブ線を導入する必要がない。そのため、切断端面に上述の微細クラックが生成されることもなく、高強度の強化ガラス板を得ることができる。特許文献１には、レーザ光によりガラス板を切断する方法が開示されている。 In recent years, a method of cutting a tempered glass plate by heating the inside of the tempered glass plate with a laser beam and controlling the extension of initial cracks introduced into the end face instead of the main surface of the tempered glass plate. Was developed. In the cutting using such a laser beam, it is not necessary to introduce a scribe line into the main surface of the tempered glass plate as in the prior art. Therefore, a high-strength tempered glass plate can be obtained without generating the above-mentioned fine cracks on the cut end face. Patent Document 1 discloses a method of cutting a glass plate with a laser beam.
国際公開第２０１０／１２６９７７号International Publication No. 2010/126977
　発明者は、レーザ光を用いた強化ガラス板の切断に関し、以下の課題を見出した。
　レーザ光を用いて強化ガラス板を切断する場合、強化ガラス板に照射されるレーザ光の条件が適切でないと、切断線が切断予定線から外れ、切り出された強化ガラスパネルが寸法不良となるおそれがあった。 The inventor has found the following problems regarding cutting of a tempered glass plate using a laser beam.
When cutting a tempered glass plate using laser light, if the conditions of the laser light applied to the tempered glass plate are not appropriate, the cutting line may deviate from the planned cutting line and the cut out tempered glass panel may be defective in dimensions. was there.
　本発明は、上記に鑑みなされたものであって、切り出された強化ガラスパネルの寸法不良を抑制した強化ガラス板の切断方法を提供することを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to provide a method for cutting a tempered glass plate that suppresses a dimensional defect of the cut tempered glass panel.
　本発明の第１の態様に係る強化ガラス板の切断方法は、
　残留圧縮応力を有する表面層および裏面層と、当該表面層および裏面層との間に形成され、内部残留引張応力ＣＴ（ＭＰａ）を有する中間層とを備える強化ガラス板を、当該強化ガラス板に照射されるレーザ光の照射領域を移動させることで切断する強化ガラス板の切断方法であって、
　前記表面層および前記裏面層の厚さをＤＯＬ（μｍ）、前記強化ガラス板の厚さをｔ１（μｍ）、前記強化ガラス板のヤング率をＹ（ＭＰａ）として、ＵＣＴ＝｛ＣＴ２×（ｔ１－２×ＤＯＬ)｝／（２×Ｙ）で表現される前記内部残留引張応力ＣＴに基づく単位面積当たりのひずみエネルギーＵＣＴ（Ｊ／ｍ２）を２．５Ｊ／ｍ２以上とし、
　前記強化ガラス板の切断線がコーナー部と直線部とを含み、前記直線部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ１よりも、前記コーナー部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ２を、大きくし、
　前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を、前記直線部における前記照射エネルギーＥ１から前記コーナー部における前記照射エネルギーＥ２への切換速度よりも小さくするものである。 The method for cutting a tempered glass sheet according to the first aspect of the present invention is as follows.
A tempered glass plate comprising a surface layer and a back surface layer having a residual compressive stress, and an intermediate layer formed between the surface layer and the back surface layer and having an internal residual tensile stress CT (MPa) is applied to the tempered glass plate. A method of cutting a tempered glass plate that is cut by moving the irradiation region of the irradiated laser beam,
U CT = {CT 2 , where DOL (μm) is the thickness of the surface layer and the back layer, t 1 (μm) is the thickness of the tempered glass plate, and Y (MPa) is the Young's modulus of the tempered glass plate. The strain energy U CT (J / m 2 ) per unit area based on the internal residual tensile stress CT expressed by × (t 1 −2 × DOL)} / (2 × Y) is 2.5 J / m 2 or more. age,
The cutting line of the tempered glass plate includes a corner portion and a straight portion, and the tempered glass at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated on the tempered glass plate at the straight portion. Increasing the irradiation energy E2 per unit irradiation area of the laser beam irradiated to the plate,
The switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. is there.
　本発明の第２の態様に係る強化ガラス板の切断方法は、前記第１の態様において、
　前記強化ガラス板に入射される前記レーザ光の実効的な出力をＰｅ（Ｗ）、前記レーザ光の走査速度をｖ（ｍｍ／ｓ）、前記レーザ光に対する前記強化ガラス板の吸収係数をα（ｍｍ－１）、前記強化ガラス板の厚さをｔ２（ｍｍ）、前記強化ガラス板の線膨張係数をαＬ（Ｋ－１）、前記強化ガラス板の密度をρ（ｇ／ｍｍ３）、前記強化ガラス板の比熱をｃ（Ｊ／ｇ／Ｋ）として、Ｋ＝Ｐｅ／ｖ×ｅｘｐ（－α×ｔ２）×（Ｙ×αＬ）／（ｔ２×ρ×ｃ）で表現される切断指数Ｋ（Ｎ／ｍｍ）を１５０Ｎ／ｍｍ以下とするものである。 The method for cutting a strengthened glass sheet according to the second aspect of the present invention is the first aspect,
The effective output of the laser light incident on the tempered glass plate is Pe (W), the scanning speed of the laser light is v (mm / s), and the absorption coefficient of the tempered glass plate with respect to the laser light is α ( mm −1 ), the thickness of the tempered glass plate is t 2 (mm), the linear expansion coefficient of the tempered glass plate is α L (K −1 ), and the density of the tempered glass plate is ρ (g / mm 3 ). The specific heat of the tempered glass plate is expressed as K = Pe / v × exp (−α × t 2 ) × (Y × α L ) / (t 2 × ρ × c), where c (J / g / K). The cutting index K (N / mm) is 150 N / mm or less.
　本発明の第３の態様に係る強化ガラス板の切断方法は、前記第１又は２の態様において、
　前記強化ガラス板と前記レーザ光とが、前記レーザ光に対する前記強化ガラス板の吸収係数をα（ｍｍ－１）、前記強化ガラス板の厚さをｔ２（ｍｍ）として、０＜α×ｔ２≦３．０の条件を満たすものである。 The method for cutting a strengthened glass sheet according to the third aspect of the present invention is the first or second aspect,
The tempered glass plate and the laser beam are expressed as follows: 0 <α × t, where α (mm −1 ) is the absorption coefficient of the tempered glass plate with respect to the laser beam and t 2 (mm) is the thickness of the tempered glass plate. 2 ≦ 3.0 is satisfied.
　本発明の第４の態様に係る強化ガラス板の切断方法は、前記第１～３のいずれかの態様において、
　前記中間層の残留引張応力が大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を大きくするものである。 The method for cutting a strengthened glass sheet according to the fourth aspect of the present invention, in any one of the first to third aspects,
As the residual tensile stress of the intermediate layer increases, the switching speed from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the linear portion is increased.
　本発明の第５の態様に係る強化ガラス板の切断方法は、前記第１～４のいずれかの態様において、
　前記レーザ光の照射領域の移動速度を速くすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行うものである。 The method for cutting a strengthened glass sheet according to the fifth aspect of the present invention, in any one of the first to fourth aspects,
Switching from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the straight portion is performed by increasing the moving speed of the irradiation region of the laser light.
　本発明の第６の態様に係る強化ガラス板の切断方法は、前記第１～５のいずれかの態様において、
　前記レーザ光の出力を小さくすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行うものである。 The method for cutting a tempered glass sheet according to a sixth aspect of the present invention, in any one of the first to fifth aspects,
By reducing the output of the laser beam, the irradiation energy E2 at the corner portion is switched to the irradiation energy E1 at the straight portion.
　本発明の第７の態様に係る強化ガラス板の切断方法は、前記第１～６のいずれかの態様において、
　前記レーザ光の照射領域の面積を大きくすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行うものである。 A method for cutting a strengthened glass sheet according to a seventh aspect of the present invention, in any one of the first to sixth aspects,
By increasing the area of the laser light irradiation region, the irradiation energy E2 at the corner portion is switched to the irradiation energy E1 at the straight portion.
　本発明の第８の態様に係る強化ガラス板の切断方法は、前記第１～７のいずれか一つの態様において、
　前記強化ガラス板の吸収係数αが大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を小さくするものである。 The method for cutting a strengthened glass sheet according to the eighth aspect of the present invention is the method according to any one of the first to seventh aspects,
As the absorption coefficient α of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
　本発明の第９の態様に係る強化ガラス板の切断方法は、前記第１～８のいずれか一つの態様において、
　前記強化ガラス板の熱膨張係数が大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を小さくするものである。 The method for cutting a strengthened glass sheet according to the ninth aspect of the present invention, in any one of the first to eighth aspects,
As the thermal expansion coefficient of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
　本発明の第１０の態様に係る強化ガラス板の切断方法は、前記第１～９のいずれか一つの態様において、
　前記強化ガラス板の厚さが厚くなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を大きくするものである。 The method for cutting a strengthened glass sheet according to the tenth aspect of the present invention is the method according to any one of the first to ninth aspects,
As the thickness of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are increased.
　本発明の第１１の態様に係る強化ガラス板の切断方法は、前記第１～１０のいずれか一つの態様において、
　前記強化ガラス板の前記レーザ光の照射領域に、前記レーザ光の入射側から気体を吹き付けて冷却するものである。 The method for cutting a strengthened glass sheet according to an eleventh aspect of the present invention, in any one of the first to tenth aspects,
A gas is blown from the incident side of the laser beam to the irradiation region of the laser beam of the tempered glass plate to cool it.
　本発明の第１２の態様に係る強化ガラス板の切断方法は、前記第１１の態様において、
　前記強化ガラス板の前記コーナー部に、前記レーザ光の出射側から気体を吹き付けて冷却するものである。 The tempered glass sheet cutting method according to the twelfth aspect of the present invention, in the eleventh aspect,
Gas is blown from the laser beam emission side to the corner portion of the tempered glass plate to cool it.
　本発明の第１３の態様に係る強化ガラス板切断装置は、
　残留圧縮応力を有する表面層および裏面層と、当該表面層および裏面層との間に形成され、内部残留引張応力を有する中間層とを備える強化ガラス板を、当該強化ガラス板に照射されるレーザ光の照射領域を移動させることで切断する強化ガラス板切断装置であって、
　前記強化ガラス板を保持するガラス保持部と、
　前記強化ガラス板を切断するためのレーザ光を出力するレーザ出力部と、
　前記レーザ出力部を制御する制御部と、を備え、
　前記強化ガラス板の切断線がコーナー部と直線部とを含み、
　前記制御部は、
　前記直線部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ１よりも、前記コーナー部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ２を大きくし、
　前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を、前記直線部における前記照射エネルギーＥ１から前記コーナー部における前記照射エネルギーＥ２への切換速度よりも小さくするものである。 The tempered glass sheet cutting device according to the thirteenth aspect of the present invention is:
Laser that irradiates the tempered glass plate with a tempered glass plate that is formed between the surface layer and the back surface layer having a residual compressive stress and an intermediate layer that has an internal residual tensile stress. A tempered glass sheet cutting device that cuts by moving an irradiation area of light,
A glass holding part for holding the tempered glass plate;
A laser output unit for outputting a laser beam for cutting the tempered glass plate;
A control unit for controlling the laser output unit,
The cutting line of the tempered glass plate includes a corner portion and a straight portion,
The controller is
The irradiation energy E2 per unit irradiation area of the laser light irradiated to the tempered glass plate at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated to the tempered glass plate at the linear portion. Make it bigger
The switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. is there.
　本発明により、切り出された強化ガラスパネルの寸法不良を抑制した強化ガラス板の切断方法を提供することができる。 According to the present invention, it is possible to provide a method for cutting a tempered glass sheet in which dimensional defects of the cut tempered glass panel are suppressed.
レーザ光を照射する前の強化ガラス板の断面図である。It is sectional drawing of the tempered glass board before irradiating a laser beam. レーザ光を照射する前の強化ガラス板の残留応力の分布を示す模式図である。It is a schematic diagram which shows distribution of the residual stress of the tempered glass board before irradiating a laser beam. 強化ガラス板の切断方法を説明するための斜視図である。It is a perspective view for demonstrating the cutting method of a tempered glass board. 図３のＡ－Ａ線に沿った断面図である。FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. 図３のＢ－Ｂ線に沿った断面図である。FIG. 4 is a cross-sectional view taken along line BB in FIG. 3. 実施の形態１に係る強化ガラス板の切断方法を説明するための図である。It is a figure for demonstrating the cutting method of the tempered glass board which concerns on Embodiment 1. FIG. 直線部とコーナー部とにおける単位照射エネルギーＥの切り替えを模式的に示したグラフである。It is the graph which showed typically switching of unit irradiation energy E in a straight part and a corner part. 強化ガラス板についての切断結果を示す表である。It is a table | surface which shows the cutting result about a tempered glass board. 非強化ガラス板についての切断結果を示す表である。It is a table | surface which shows the cutting result about a non-tempered glass board. 強化ガラス板および非強化ガラス板についての切断結果を示す表である。It is a table | surface which shows the cutting result about a tempered glass board and a non-tempered glass board. レーザ光を用いて非強化ガラス板を切断する際に作用する応力を説明するための図である。It is a figure for demonstrating the stress which acts when a non-tempered glass board is cut | disconnected using a laser beam. レーザ光を用いて強化ガラス板を切断する際に作用する応力の一例を示す図である。It is a figure which shows an example of the stress which acts when a tempered glass board is cut | disconnected using a laser beam. レーザ光を用いて強化ガラス板を切断する際に作用する応力の他の例を示す図である。It is a figure which shows the other example of the stress which acts when cut | disconnecting a tempered glass board using a laser beam. 参考例２に係る切断予定線の形状を示す図である。It is a figure which shows the shape of the scheduled cutting line which concerns on the reference example 2. FIG. サンプル１～１２について、レーザ波長λ、内部ひずみエネルギーＵＣＴ、臨界照射エネルギーＥｃ、及び両者を導出するための諸条件が示された表である。6 is a table showing laser wavelength λ, internal strain energy U CT , critical irradiation energy Ec, and various conditions for deriving both of samples 1 to 12; 図１５の表に示した臨界照射エネルギーＥｃの内部ひずみエネルギーＵＣＴ依存性を示すグラフである。It is a graph which shows the internal strain energy UCT dependence of the critical irradiation energy Ec shown in the table | surface of FIG. 図１５の表に示した臨界切断指数Ｋｃの内部ひずみエネルギーＵＣＴ依存性を示すグラフである。It is a graph which shows the internal strain energy UCT dependence of the critical cutting | disconnection index Kc shown in the table | surface of FIG. 切り出された強化ガラスパネルの形状を示している。The shape of the cut-out tempered glass panel is shown. 強化ガラス板の切断条件を示す表である。It is a table | surface which shows the cutting conditions of a tempered glass board. 実施例１に係る強化ガラス板の切断方法に用いた冷却ノズルの断面図である。It is sectional drawing of the cooling nozzle used for the cutting method of the tempered glass board concerning Example 1. FIG. 強化ガラス板の切断結果を示す表である。It is a table | surface which shows the cutting | disconnection result of a tempered glass board. 寸法誤差の最大値δｍａｘの単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ依存性を示すグラフである。It is a graph which shows the variation (DELTA) E / T dependence of the unit irradiation energy per unit time of the maximum value (delta) max of a dimension error. 実施の形態２に係る強化ガラス板切断装置を説明するための図である。It is a figure for demonstrating the tempered glass board cutting device which concerns on Embodiment 2. FIG.
　以下、本発明を適用した具体的な実施の形態について、図面を参照しながら詳細に説明する。ただし、本発明が以下の実施の形態に限定される訳ではない。また、説明を明確にするため、以下の記載及び図面は、適宜、簡略化されている。 Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.
（実施の形態１）
＜強化ガラス板の構造及び切断方法の概要＞
　まず、図１～５を参照して、強化ガラス板の構造、及び強化ガラス板の切断方法の概要について説明する。
　まず、図１、２を参照して、強化ガラス板の構造について説明する。図１は、レーザ光を照射する前の強化ガラス板１０の断面図である。図１において、矢印の方向は、残留応力の作用方向を示し、矢印の大きさは、応力の大きさを示す。図１に示すように、強化ガラス板１０は、表面層１３及び裏面層１５と、表面層１３と裏面層１５との間に設けられた中間層１７とを有する。表面層１３及び裏面層１５には、下記の風冷強化法や化学強化法により圧縮応力が残留している。また、その反作用として、中間層１７には引張応力が残留している。 (Embodiment 1)
<Outline of structure and cutting method of tempered glass plate>
First, with reference to FIGS. 1 to 5, the structure of the tempered glass sheet and the outline of the method of cutting the tempered glass sheet will be described.
First, the structure of the tempered glass plate will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a tempered glass plate 10 before irradiation with laser light. In FIG. 1, the direction of the arrow indicates the direction of action of the residual stress, and the size of the arrow indicates the magnitude of the stress. As shown in FIG. 1, the tempered glass plate 10 includes a front surface layer 13 and a back surface layer 15, and an intermediate layer 17 provided between the front surface layer 13 and the back surface layer 15. Compressive stress remains on the front surface layer 13 and the back surface layer 15 by the following air cooling strengthening method or chemical strengthening method. Further, as a reaction, tensile stress remains in the intermediate layer 17.
　強化ガラス板１０は、例えば風冷強化法や化学強化法などで作製される。強化用のガラスの種類は、用途に応じて選択される。例えば、自動車用窓ガラスや建築用窓ガラス、ＰＤＰ（Plasma Display Panel）用のガラス基板、カバーガラスの場合、強化用のガラスとしては、アルカリアルミノシリケートガラスやソーダライムガラスが用いられる。 The tempered glass plate 10 is produced by, for example, an air cooling strengthening method or a chemical strengthening method. The kind of glass for reinforcement | strengthening is selected according to a use. For example, in the case of an automobile window glass, an architectural window glass, a glass substrate for PDP (Plasma Display Panel), and a cover glass, alkali aluminosilicate glass or soda lime glass is used as the reinforcing glass.
　風冷強化法は、軟化点付近の温度のガラスを表面及び裏面から急冷し、ガラスの表面及び裏面と内部との間に温度差をつけることで、圧縮応力が残留する表面層及び裏面層を形成する。風冷強化法は、厚いガラスを強化するのに好適である。 The air-cooling strengthening method rapidly cools the glass near the softening point from the front and back surfaces, and creates a temperature difference between the front and back surfaces of the glass and the inside, so that the surface layer and the back surface layer where compressive stress remains are formed. Form. The air cooling strengthening method is suitable for strengthening thick glass.
　化学強化法は、ガラスの表面及び裏面をイオン交換し、ガラスに含まれる小さなイオン半径のイオン（例えば、Ｌｉイオン、Ｎａイオン）を、大きなイオン半径のイオン（例えば、Ｋイオン）に置換することで、圧縮応力が残留する表面層及び裏面層を形成する。化学強化法は、アルカリアルミノシリケートガラスやソーダライムガラスを強化するのに好適である。 In the chemical strengthening method, the front and back surfaces of glass are ion-exchanged, and ions having a small ion radius (for example, Li ions and Na ions) contained in the glass are replaced with ions having a large ion radius (for example, K ions). Thus, the surface layer and the back surface layer in which the compressive stress remains are formed. The chemical strengthening method is suitable for strengthening alkali aluminosilicate glass or soda lime glass.
　図２は、レーザ光を照射する前の強化ガラス板の残留応力の分布を示す模式図である。
　図２に示すように、表面層１３及び裏面層１５に残留する圧縮応力（＞０）は、強化ガラス板１０の表面１２及び裏面１４から内部に向けて徐々に小さくなる傾向がある。また、中間層１７に残留する引張応力（＞０）は、ガラスの内部から表面１２及び裏面１４に向けて徐々に小さくなる傾向がある。 FIG. 2 is a schematic diagram showing a distribution of residual stress of the tempered glass plate before irradiation with laser light.
As shown in FIG. 2, the compressive stress (> 0) remaining on the front surface layer 13 and the back surface layer 15 tends to gradually decrease from the front surface 12 and the back surface 14 of the tempered glass plate 10 toward the inside. Further, the tensile stress (> 0) remaining in the intermediate layer 17 tends to gradually decrease from the inside of the glass toward the front surface 12 and the back surface 14.
　図２において、ＣＳは表面層１３や裏面層１５における最大残留圧縮応力（表面圧縮応力）（＞０）、ＣＴは中間層１７における内部残留引張応力（中間層１７の残留引張応力の平均値）（＞０）、ＤＯＬは表面層１３及び裏面層１５の厚さ、ｔは強化ガラス板１０の厚さ、をそれぞれ示す。従って、中間層１７の厚さは、ｔ－２×ＤＯＬとなる。 In FIG. 2, CS is the maximum residual compressive stress (surface compressive stress) (> 0) in the surface layer 13 and the back layer 15, and CT is the internal residual tensile stress in the intermediate layer 17 (average value of residual tensile stress in the intermediate layer 17). (> 0), DOL indicates the thickness of the front surface layer 13 and the back surface layer 15, and t indicates the thickness of the tempered glass plate 10, respectively. Therefore, the thickness of the intermediate layer 17 is t−2 × DOL.
　また、強化ガラス板の内部残留引張応力ＣＴ（ＭＰａ）は、通常、表面圧縮応力ＣＳ（ＭＰａ）及び表面層１３及び裏面層１５の厚さＤＯＬ（μｍ）を測定し、その測定値と、強化ガラス板の厚さｔ１（μｍ）とから以下の式１を用いて算出する。
       ＣＴ＝（ＣＳ×ＤＯＬ）／（ｔ１－２×ＤＯＬ）　・・・式１
　そして、内部残留引張応力ＣＴによる単位面積当たりのひずみエネルギー（以下、単に「内部ひずみエネルギー」という）ＵＣＴ（Ｊ／ｍ２）は、強化ガラス板のヤング率Ｙ（ＭＰａ）を用いて以下の式２により求めることができる。
       ＵＣＴ＝｛ＣＴ２×（ｔ１－２×ＤＯＬ)｝／（２×Ｙ）　・・・式２ Further, the internal residual tensile stress CT (MPa) of the tempered glass plate is usually measured by measuring the surface compressive stress CS (MPa) and the thickness DOL (μm) of the surface layer 13 and the back surface layer 15, and the measured values and strengthening. It is calculated using the thickness t 1 ([mu] m) and formula 1 below color of the glass plate.
CT = (CS × DOL) / (t 1 −2 × DOL) Equation 1
The strain energy per unit area (hereinafter simply referred to as “internal strain energy”) U CT (J / m 2 ) by the internal residual tensile stress CT is expressed as follows using the Young's modulus Y (MPa) of the tempered glass sheet. It can be obtained from Equation 2.
U CT = {CT 2 × (t 1 −2 × DOL)} / (2 × Y) Equation 2
　発明者は、種々の内部ひずみエネルギーＵＣＴを有する強化ガラス板について、切断に必要なレーザ光の照射エネルギーＥの最小値（以下、臨界照射エネルギーという）Ｅｃを調査した。その結果、強化ガラス板の内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２とすると、切断条件が同一でも、臨界照射エネルギーＥｃが急激に（具体的には数倍程度）上昇するとともに、切断精度も悪化することを見出した。同時に、発明者は、強化ガラス板の内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とすると、強化ガラス板の材質、厚さ及びレーザ波長が同一であれば、臨界照射エネルギーＥｃは、略一定値となり、切断精度も向上することを見出した。つまり、発明者は、強化ガラス板を切断する場合、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とすることにより、内部残留引張応力によるクラック伸展が支配的となり、小さい照射エネルギーで精度良く切断することができることを見出した。 The inventor investigated the minimum value (hereinafter referred to as critical irradiation energy) Ec of the irradiation energy E of the laser light necessary for cutting, for the tempered glass plate having various internal strain energies U CT . As a result, when the internal strain energy U CT <2.5 J / m 2 of the tempered glass plate, even if the cutting conditions are the same, the critical irradiation energy Ec increases rapidly (specifically, about several times), and the cutting accuracy I also found it worse. At the same time, if the inventor makes the internal strain energy U CT ≧ 2.5 J / m 2 of the tempered glass plate, the critical irradiation energy Ec is substantially constant if the material, thickness and laser wavelength of the tempered glass plate are the same. It was found that the cutting accuracy was improved. That is, when the inventor cuts the tempered glass sheet, by setting the internal strain energy U CT ≧ 2.5 J / m 2 , the crack extension due to the internal residual tensile stress becomes dominant, and the cutting is accurately performed with a small irradiation energy. Found that you can.
　つまり、内部ひずみエネルギーＵＣＴ＝２．５Ｊ／ｍ２近傍において、切断モードの変換が生じているものと考えられる。具体的には、強化ガラス板を切断するためのクラック伸展エネルギーとして、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２の場合、内部ひずみエネルギーに加え、レーザ光の照射エネルギーが必要となり、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２の場合、内部ひずみエネルギーのみとなる。そして、ＵＣＴ≧２．５Ｊ／ｍ２の場合には、クラックを進展させるためでなく、逆にクラックの伸展を抑制し、制御するために、レーザ光の照射エネルギーが必要になる。 That is, it is considered that cutting mode conversion occurs in the vicinity of the internal strain energy U CT = 2.5 J / m 2 . Specifically, when the internal strain energy U CT <2.5 J / m 2 as the crack extension energy for cutting the tempered glass plate, in addition to the internal strain energy, laser beam irradiation energy is required. When energy U CT ≧ 2.5 J / m 2 , only internal strain energy is obtained. In the case of U CT ≧ 2.5 J / m 2 , the irradiation energy of the laser beam is required not only for the purpose of crack growth but conversely for suppressing and controlling the crack extension.
　ここで、最大残留圧縮応力ＣＳや内部残留引張応力ＣＴ、表面層１３及び裏面層１５の厚さＤＯＬは、強化処理条件で調節可能である。例えば、最大残留圧縮応力ＣＳや内部残留引張応力ＣＴ、表面層１３及び裏面層１５の厚さＤＯＬは、風冷強化法の場合、ガラスの冷却速度などで調節可能である。また、最大残留圧縮応力ＣＳ、内部残留引張応力ＣＴ、表面層１３及び裏面層１５の厚さＤＯＬは、化学強化法の場合、ガラスを処理液（例えば、ＫＮＯ３溶融塩）に浸漬してイオン交換するので、処理液の濃度や温度、浸漬時間などで調節可能である。なお、本実施の形態の表面層１３及び裏面層１５は、同じ厚さＤＯＬ及び最大残留圧縮応力ＣＳを有するが、異なる厚さや最大残留圧縮応力を有してもよい。 Here, the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the front surface layer 13 and the back surface layer 15 can be adjusted by the strengthening process conditions. For example, the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the front surface layer 13 and the back surface layer 15 can be adjusted by the cooling rate of the glass in the case of the air cooling strengthening method. In the case of the chemical strengthening method, the maximum residual compressive stress CS, internal residual tensile stress CT, and thickness DOL of the surface layer 13 and the back surface layer 15 are determined by immersing glass in a treatment liquid (for example, KNO 3 molten salt). Since it is exchanged, it can be adjusted by the concentration, temperature, and immersion time of the treatment liquid. Note that the front surface layer 13 and the back surface layer 15 of the present embodiment have the same thickness DOL and the maximum residual compressive stress CS, but may have different thicknesses and maximum residual compressive stress.
　図３は、強化ガラス板の切断方法を説明するための図である。図３に示すように、強化ガラス板１０の表面１２にレーザ光２０を照射し、強化ガラス板１０の表面１２上で、レーザ光２０の照射領域２２を移動（走査）させることで、強化ガラス板１０に応力を印加して、強化ガラス板１０を切断する。 FIG. 3 is a diagram for explaining a method of cutting a tempered glass sheet. As shown in FIG. 3, the surface 12 of the tempered glass plate 10 is irradiated with laser light 20, and the irradiation region 22 of the laser light 20 is moved (scanned) on the surface 12 of the tempered glass plate 10, thereby strengthening glass. Stress is applied to the plate 10 to cut the tempered glass plate 10.
　強化ガラス板１０の端部には、切断開始位置に、初期クラックが予め形成されている。初期クラックの形成方法は、一般的な方法であって良く、例えばカッタやヤスリ、レーザで形成される。なお、レーザ光を用いた内部加熱切断では、強化ガラス板１０の表面１２に、切断予定線に沿ったスクライブ線（溝線）を形成する必要がない。 At the end of the tempered glass plate 10, an initial crack is formed in advance at the cutting start position. The method for forming the initial crack may be a general method, for example, a cutter, a file, or a laser. In the internal heating cutting using laser light, it is not necessary to form scribe lines (groove lines) along the planned cutting line on the surface 12 of the tempered glass plate 10.
　強化ガラス板１０の表面１２上において、レーザ光２０の照射領域２２は、強化ガラス板１０の端部から内側に向けて、切断予定線に沿って、直線状や曲線状に移動される。これによって、強化ガラス板１０の端部から内側に向けてクラック３０を伸展させ、強化ガラス板１０を切断する。 On the surface 12 of the tempered glass plate 10, the irradiation region 22 of the laser beam 20 is moved in a straight line shape or a curved shape along the planned cutting line from the end of the tempered glass plate 10 toward the inside. As a result, the crack 30 is extended from the end of the tempered glass plate 10 toward the inside, and the tempered glass plate 10 is cut.
　強化ガラス板１０の表面１２上において、レーザ光２０の照射領域２２を移動させるため、強化ガラス板１０を支持する保持具を、移動又は回転してもよいし、レーザ光２０の光源を移動してもよい。また、レーザ光２０の経路の途中に設けられるミラーを回転してもよい。 In order to move the irradiation region 22 of the laser light 20 on the surface 12 of the tempered glass plate 10, the holder supporting the tempered glass plate 10 may be moved or rotated, or the light source of the laser light 20 is moved. May be. Further, a mirror provided in the middle of the path of the laser beam 20 may be rotated.
　強化ガラス板１０の表面１２上において、レーザ光２０の照射領域２２は、強化ガラス板１０の厚さや、最大残留圧縮応力ＣＳ、内部残留引張応力ＣＴ、表面層１３や裏面層１５の厚さＤＯＬ、レーザ光２０の光源の出力などに応じた速度で移動される。 On the surface 12 of the tempered glass plate 10, the irradiation region 22 of the laser beam 20 includes the thickness of the tempered glass plate 10, the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the surface layer 13 and the back surface layer 15. The laser beam 20 is moved at a speed corresponding to the output of the light source.
　レーザ光２０の光源としては、特に限定されないが、例えば、ＵＶレーザ（波長：３５５ｎｍ）、グリーンレーザ（波長：５３２ｎｍ）、半導体レーザ（波長：８０８ｎｍ、９４０ｎｍ、９７５ｎｍ）、ファイバーレーザ（波長：１０６０～１１００ｎｍ）、ＹＡＧレーザ（波長：１０６４ｎｍ、２０８０ｎｍ、２９４０ｎｍ）、中赤外光パラメトリック発振器を使用したレーザ（波長：２６００～３４５０ｎｍ）などが挙げられる。レーザ光２０の発振方式に制限はなく、レーザ光を連続発振するＣＷレーザ、レーザ光を断続発振するパルスレーザのいずれも使用可能である。また、レーザ光２０の強度分布に制限はなく、ガウシアン型であっても、トップハット型であってもよい。 The light source of the laser light 20 is not particularly limited. For example, a UV laser (wavelength: 355 nm), a green laser (wavelength: 532 nm), a semiconductor laser (wavelength: 808 nm, 940 nm, 975 nm), a fiber laser (wavelength: 1060 to 1100 nm), YAG laser (wavelength: 1064 nm, 2080 nm, 2940 nm), laser using a mid-infrared light parametric oscillator (wavelength: 2600 to 3450 nm), and the like. There is no limitation on the oscillation method of the laser beam 20, and either a CW laser that continuously oscillates the laser beam or a pulse laser that intermittently oscillates the laser beam can be used. The intensity distribution of the laser beam 20 is not limited, and may be a Gaussian type or a top hat type.
　光源から出射されたレーザ光２０は、集光レンズなどで集光され、強化ガラス板１０の表面１２に結像される。レーザ光２０の集光位置は、強化ガラス板１０の表面１２を基準として、レーザ光源側であってもよいし、裏面１４側であってもよい。また、加熱温度が高くなりすぎない、すなわち徐冷点以下を保てる集光面積であれば、レーザ光２０の集光位置は強化ガラス板１０中であってもよい。 The laser light 20 emitted from the light source is condensed by a condenser lens or the like and imaged on the surface 12 of the tempered glass plate 10. The condensing position of the laser light 20 may be on the laser light source side or the back surface 14 side with respect to the front surface 12 of the tempered glass plate 10. Further, the condensing position of the laser beam 20 may be in the tempered glass plate 10 as long as the heating temperature does not become too high, that is, the condensing area can keep the annealing point or less.
　レーザ光２０の光軸は、強化ガラス板１０の表面１２において、例えば図３に示すように表面１２と直交していてもよいし、表面１２と斜めに交わっていてもよい。 The optical axis of the laser beam 20 may be perpendicular to the surface 12 on the surface 12 of the tempered glass plate 10, for example, as shown in FIG.
　レーザ光２０に対する強化ガラス板１０の吸収係数をα（ｍｍ－１）、強化ガラス板１０の厚さをｔ２（ｍｍ）として、強化ガラス板１０とレーザ光２０とが、０＜α×ｔ２≦３．０の式を満たす場合、レーザ光２０のみの作用ではなく、中間層１７の残留引張応力によるクラックの伸展を利用して強化ガラス板１０を切断することができる。すなわち、上記条件で、レーザ光２０の照射領域２２における中間層１７を徐冷点以下の温度で加熱することによって、中間層１７の残留引張応力によって強化ガラス板１０に生じるクラック３０の伸展を制御して、残留引張応力によるクラック３０によって強化ガラス板１０を切断することが可能となる。なお、中間層１７を徐冷点以下の温度で加熱するのは、徐冷点を超えて加熱すると、レーザ光が通過する短時間でもガラスが高温となり粘性流動が発生しやすい状態となるため、この粘性流動によりレーザ光によって発生させた圧縮応力が緩和されるからである。なお、強化ガラス板１０の厚さ（板厚）ｔの値ｔ２（ｍｍ）は式１、２における値ｔ１（μｍ）と単位のみが異なる。 Assuming that the absorption coefficient of the tempered glass plate 10 with respect to the laser beam 20 is α (mm −1 ) and the thickness of the tempered glass plate 10 is t 2 (mm), the tempered glass plate 10 and the laser beam 20 have 0 <α × t When satisfy | filling the formula of 2 <= 3.0, the tempered glass board 10 can be cut | disconnected using the extension of the crack by the residual tensile stress of the intermediate | middle layer 17 instead of the effect | action of only the laser beam 20. FIG. That is, under the above conditions, heating of the intermediate layer 17 in the irradiation region 22 of the laser light 20 at a temperature equal to or lower than the annealing point controls the extension of the crack 30 generated in the tempered glass plate 10 by the residual tensile stress of the intermediate layer 17. Thus, the tempered glass plate 10 can be cut by the crack 30 caused by the residual tensile stress. The intermediate layer 17 is heated at a temperature below the annealing point because when the heating is performed above the annealing point, the glass becomes high temperature and a viscous flow easily occurs even in a short time during which the laser beam passes. This is because the compressive stress generated by the laser beam is relieved by this viscous flow. Note that the value t 2 (mm) of the thickness (plate thickness) t of the tempered glass plate 10 differs from the value t 1 (μm) in Equations 1 and 2 only in units.
　強化ガラス板１０に入射する前のレーザ光２０の強度をＩ０とし、強化ガラス板１０中を距離Ｌ（ｍｍ）だけ移動したときのレーザ光２０の強度をＩとすると、ランベルト・ベールの法則により次式が成立する。
       Ｉ＝Ｉ０×ｅｘｐ（－α×Ｌ） If the intensity of the laser beam 20 before entering the tempered glass plate 10 is I 0, and the intensity of the laser beam 20 when moved through the tempered glass plate 10 by a distance L (mm) is I, the Lambert-Beer law The following equation is established.
I = I 0 × exp (−α × L)
　α×ｔ２を０より大きく３．０以下とすることで、レーザ光２０が、強化ガラス板１０の表面で吸収されずに内部にまで到達するようになるため、強化ガラス板１０の内部を十分に加熱できる。その結果、強化ガラス板１０に生じる応力は、図１に示す状態から、図４や図５に示す状態に変化する。 By making α × t 2 greater than 0 and 3.0 or less, the laser light 20 reaches the inside without being absorbed by the surface of the tempered glass plate 10. It can be heated sufficiently. As a result, the stress generated in the tempered glass plate 10 changes from the state shown in FIG. 1 to the state shown in FIG. 4 or FIG.
　図４は、図３のＡ－Ａ線に沿った断面図であって、レーザ光の照射領域を含む断面図である。図５は、図３のＢ－Ｂ線に沿った断面図であって、図４に示す断面よりも後方の断面である。ここで、「後方」とは、レーザ光２０の走査方向後方を意味する。図４及び図５において、矢印の方向は、応力の作用方向を示し、矢印の長さは、応力の大きさを示す。 FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and includes a laser light irradiation region. FIG. 5 is a cross-sectional view taken along line BB in FIG. 3, and is a rear cross section from the cross section shown in FIG. Here, “rear” means the rear of the laser beam 20 in the scanning direction. 4 and 5, the direction of the arrow indicates the direction of the applied stress, and the length of the arrow indicates the magnitude of the stress.
　レーザ光２０の照射領域２２における中間層１７では、レーザ光２０の強度が十分に高いので、温度が周辺に比べて高くなり、図１及び図２に示す残留引張応力よりも小さい引張応力、又は、圧縮応力が生じる。残留引張応力よりも小さい引張応力、又は、圧縮応力が生じている部分では、クラック３０の伸展が抑制される。クラック３０の伸展を確実に防止するため、図４に示すように、圧縮応力が生じていることが好ましい。 In the intermediate layer 17 in the irradiation region 22 of the laser beam 20, since the intensity of the laser beam 20 is sufficiently high, the temperature is higher than that of the surrounding area, and a tensile stress smaller than the residual tensile stress shown in FIGS. , Compressive stress occurs. In a portion where a tensile stress smaller than the residual tensile stress or a compressive stress is generated, extension of the crack 30 is suppressed. In order to reliably prevent the crack 30 from extending, it is preferable that compressive stress is generated as shown in FIG.
　なお、図４に示すように、レーザ光２０の照射領域２２における表面層１３や裏面層１５では、図１及び図２に示す残留圧縮応力よりも大きい圧縮応力が生じているので、クラック３０の伸展が抑制されている。 As shown in FIG. 4, since the compressive stress larger than the residual compressive stress shown in FIGS. 1 and 2 is generated in the front surface layer 13 and the back surface layer 15 in the irradiation region 22 of the laser beam 20, Extension is suppressed.
　図４に示す圧縮応力との釣り合いのため、図４に示す断面よりも後方の断面では、図５に示すように、中間層１７に引張応力が生じる。この引張応力は、残留引張応力よりも大きく、引張応力が所定値に達している部分に、クラック３０が形成される。クラック３０は強化ガラス板１０の表面１２から裏面１４まで貫通しており、図３に示す切断は所謂フルカット切断である。 In order to balance with the compressive stress shown in FIG. 4, a tensile stress is generated in the intermediate layer 17 in the cross section behind the cross section shown in FIG. 4, as shown in FIG. 5. This tensile stress is larger than the residual tensile stress, and a crack 30 is formed in a portion where the tensile stress reaches a predetermined value. The crack 30 penetrates from the front surface 12 to the back surface 14 of the tempered glass plate 10, and the cutting shown in FIG. 3 is a so-called full cut cutting.
　この状態で、レーザ光２０の照射領域２２を移動させると、照射領域２２の位置に追従するようにクラック３０の先端位置が移動する。すなわち、図３に示す切断方法では、強化ガラス板１０を切断する際に、レーザ光の走査方向後方に発生する引張応力（図５参照）によりクラック３０の伸展方向を制御し、レーザ光が照射されている領域に発生する圧縮応力（図４参照）を用いて、クラック３０の伸展を抑制しながら切断している。つまり、レーザ光２０の照射により発生する圧縮応力を用いてクラック３０の伸展を制御している。この結果、クラック３０が切断予定線から外れて自走することを抑制することができる。 In this state, when the irradiation region 22 of the laser beam 20 is moved, the tip position of the crack 30 is moved so as to follow the position of the irradiation region 22. That is, in the cutting method shown in FIG. 3, when the tempered glass plate 10 is cut, the extension direction of the crack 30 is controlled by the tensile stress (see FIG. 5) generated behind the scanning direction of the laser light, and the laser light is irradiated. Cutting is performed while suppressing the extension of the cracks 30 by using the compressive stress (see FIG. 4) generated in the region. That is, the extension of the crack 30 is controlled using the compressive stress generated by the irradiation of the laser beam 20. As a result, it is possible to suppress the crack 30 from moving away from the planned cutting line.
　ガラスは、用途によっては、高い透明度が要求されるので、使用レーザ波長が可視光の波長領域に近い場合、α×ｔ２は０に近い程よい。しかし、α×ｔ２は、小さすぎると吸収効率が悪くなるので、好ましくは０．０００５以上（レーザ光吸収率０．０５％以上）、より好ましくは０．００２以上（レーザ光吸収率０．２％以上）、さらに好ましくは０．００４以上（レーザ光吸収率０．４％以上）である。 Since high transparency is required for glass depending on the application, α × t 2 is preferably close to 0 when the laser wavelength used is close to the wavelength region of visible light. However, since α × t 2 is too small, the absorption efficiency is deteriorated. Therefore, it is preferably 0.0005 or more (laser light absorption rate 0.05% or more), more preferably 0.002 or more (laser light absorption rate 0. 2% or more), more preferably 0.004 or more (laser light absorption rate 0.4% or more).
　ガラスは、用途によっては、逆に低い透明度が要求されるので、使用レーザ波長が可視光の波長領域に近い場合、α×ｔ２は大きい程よい。しかし、α×ｔ２が大きすぎるとレーザ光の表面吸収が大きくなるのでクラック伸展を制御できなくなる。このため、α×ｔ２は、好ましくは３．０以下（レーザ光吸収率９５％以下）、より好ましくは０．１以下（レーザ光吸収率１０％以下）、さらに好ましくは０．０２以下（レーザ光吸収率２％以下）である。 Glass, on the other hand, requires low transparency, so that when the used laser wavelength is close to the wavelength region of visible light, the larger α × t 2 is better. However, if α × t 2 is too large, the surface absorption of the laser light becomes large, and crack extension cannot be controlled. Therefore, α × t 2 is preferably 3.0 or less (laser light absorptivity 95% or less), more preferably 0.1 or less (laser light absorptivity 10% or less), and further preferably 0.02 or less ( Laser light absorption rate is 2% or less).
　強化ガラス板１０の厚さｔ２（ｍｍ）は、用途に応じて設定されるが、０．１～２．０ｍｍであることが好ましい。化学強化ガラスの場合、厚さｔ２（ｍｍ）を２．０ｍｍ以下とすることで、内部残留引張応力ＣＴを十分に高めることができる。一方、厚さｔ２（ｍｍ）が０．１ｍｍ未満になると、ガラスに化学強化処理を施すことが難しい。厚さｔ２（ｍｍ）は、より好ましくは０．３～１．５ｍｍ、さらに好ましくは０．５～１．５ｍｍである。 The thickness t 2 (mm) of the tempered glass plate 10 is set according to the application, but is preferably 0.1 to 2.0 mm. In the case of chemically strengthened glass, the internal residual tensile stress CT can be sufficiently increased by setting the thickness t 2 (mm) to 2.0 mm or less. On the other hand, when the thickness t 2 (mm) is less than 0.1 mm, it is difficult to subject the glass to chemical strengthening treatment. The thickness t 2 (mm) is more preferably 0.3 to 1.5 mm, still more preferably 0.5 to 1.5 mm.
　吸収係数αは、レーザ光２０の波長、強化ガラス板１０のガラス組成などで定まる。
　例えば１０００ｎｍ付近の近赤外線波長領域での吸収係数αは、強化ガラス板１０中の酸化鉄（ＦｅＯ、Ｆｅ２Ｏ３、Ｆｅ３Ｏ４を含む）の含有量、酸化コバルト（ＣｏＯ、Ｃｏ２Ｏ３、Ｃｏ３Ｏ４を含む）の含有量、酸化銅（ＣｕＯ、Ｃｕ２Ｏを含む）の含有量が多くなるほど大きくなる。つまり、酸化鉄などの含有量を調節することにより、α×ｔ２の値を所望の範囲に調節可能である。強化ガラス板１０中の酸化鉄の含有量は、強化ガラス板１０を構成するガラスの種類によるが、ソーダライムガラスの場合、例えば０．０２～１．０質量％である。但し、酸化鉄などの含有量が多くなるほど、強化ガラス板１０の可視光領域の透明度は低下する。 The absorption coefficient α is determined by the wavelength of the laser light 20, the glass composition of the tempered glass plate 10, and the like.
For example, the absorption coefficient α in the near-infrared wavelength region near 1000 nm includes the content of iron oxide (including FeO, Fe 2 O 3 , and Fe 3 O 4 ) in the tempered glass plate 10, and cobalt oxide (CoO, Co 2 O). 3 and Co 3 O 4 ) and copper oxide (including CuO and Cu 2 O) are increased as the content increases. That is, by adjusting the content of iron oxide or the like, the value of α × t 2 can be adjusted to a desired range. The content of iron oxide in the tempered glass plate 10 depends on the type of glass constituting the tempered glass plate 10, but in the case of soda lime glass, it is, for example, 0.02 to 1.0% by mass. However, as the content of iron oxide or the like increases, the transparency of the tempered glass plate 10 in the visible light region decreases.
　１０００ｎｍ付近の近赤外線波長領域での吸収係数（α）は、用途に応じて設定される。例えば、自動車用窓ガラスの場合、吸収係数（α）は０．３ｍｍ－１以下であることが好ましい。また、建築用窓ガラスの場合、吸収係数（α）は０．０６ｍｍ－１以下であることが好ましい。また、ディスプレイ用ガラスの場合、吸収係数（α）は０．０２ｍｍ－１以下であることが好ましい。 The absorption coefficient (α) in the near-infrared wavelength region near 1000 nm is set according to the application. For example, in the case of automobile window glass, the absorption coefficient (α) is preferably 0.3 mm −1 or less. In the case of architectural window glass, the absorption coefficient (α) is preferably 0.06 mm −1 or less. In the case of display glass, the absorption coefficient (α) is preferably 0.02 mm −1 or less.
　また、希土類原子の吸収波長付近での吸収係数αは、強化ガラス板１０中の希土類元素（例えばＹｂ）の酸化物の含有量が多くなるほど大きくなる。
　さらに、３０００ｎｍ付近の中赤外線波長領域での吸収係数αは、強化ガラス板１０中のＯＨ基の含有量が多くなるほど大きくなる。ここで、ＯＨ基の含有量は、可視光領域の透明度に影響を及ぼさない。 Further, the absorption coefficient α in the vicinity of the absorption wavelength of the rare earth atoms increases as the content of the rare earth element (for example, Yb) oxide in the tempered glass plate 10 increases.
Furthermore, the absorption coefficient α in the mid-infrared wavelength region near 3000 nm increases as the OH group content in the tempered glass plate 10 increases. Here, the OH group content does not affect the transparency in the visible light region.
　レーザ光２０の波長は、２５０～５０００ｎｍであればよいが、２５００～３５００ｎｍとすることが好ましい。レーザ光２０の波長が２５００～３５００ｎｍ（３０００ｎｍ近傍）の場合、上述の通り、可視光領域の透明度を低下させずに吸収係数αを高めることができる。その結果、レーザ光２０による加熱効率を高めることができる。レーザ光２０の波長は、２７００～３２００ｎｍとすることがさらに好ましい。 The wavelength of the laser beam 20 may be 250 to 5000 nm, but is preferably 2500 to 3500 nm. When the wavelength of the laser light 20 is 2500 to 3500 nm (near 3000 nm), as described above, the absorption coefficient α can be increased without reducing the transparency in the visible light region. As a result, the heating efficiency by the laser beam 20 can be increased. The wavelength of the laser beam 20 is more preferably 2700 to 3200 nm.
　例えばレーザ光の波長が１０００ｎｍ近傍の場合、酸化鉄含有量０．０４質量％の強化ガラス板の吸収率は、板厚ｔ２（ｍｍ）が１ｍｍの場合、約２％（透過率：約９８％）である。そのため、レーザ光の照射による加熱効率が悪い。また、Ｆｅ濃度により吸収率が変化するため、強化ガラス板の組成によりレーザ光の照射条件を大幅に変更する必要がある。
　これに対し、例えばレーザ光の波長が３０００ｎｍ近傍の場合、酸化鉄含有量によらず強化ガラス板の吸収率は、板厚が１ｍｍの場合、約５０％（透過率：約５０％）である。そのため、波長が１０００ｎｍ近傍の場合に比べ、加熱効率が向上する上、強化ガラス板の組成によりレーザ光の照射条件を大幅に変更する必要がない。 For example, when the wavelength of the laser beam is around 1000 nm, the absorptivity of the tempered glass plate having an iron oxide content of 0.04% by mass is about 2% when the plate thickness t 2 (mm) is 1 mm (transmittance: about 98). %). Therefore, the heating efficiency by laser light irradiation is poor. In addition, since the absorptance changes depending on the Fe concentration, it is necessary to significantly change the laser light irradiation conditions depending on the composition of the tempered glass plate.
On the other hand, for example, when the wavelength of the laser beam is around 3000 nm, the absorptivity of the tempered glass plate is about 50% (transmittance: about 50%) when the plate thickness is 1 mm regardless of the iron oxide content. . Therefore, the heating efficiency is improved as compared with the case where the wavelength is in the vicinity of 1000 nm, and it is not necessary to significantly change the irradiation condition of the laser beam by the composition of the tempered glass plate.
　また、波長が１０００ｎｍ近傍で吸収率が約２％の場合、例えば切断に２Ｗの吸収パワーが必要であれば、１００Ｗが投入され、９８Ｗが透過する。そのため、レーザ光の通過する切断予定線の下にテーブルが位置していると、レーザ光によりテーブルまで損傷を受けてしまう。そのため、強化ガラス板から切り出す強化ガラスパネルよりもテーブルを一回り小さくするなどの工夫が必要であった。また、透過したレーザ光の処理も必要であった。さらに、透過率が高いため、強化ガラス板の端面における反射光が悪影響を及ぼす場合があった。また、表面あるいは裏面に付着した異物によりレーザ光の吸収率が高まると、吸収量の変化が大きく、悪影響を及ぼす場合があった。さらに、Ｆｅ濃度により吸収率が２％から１％へ１％しか変化しなかった場合でも、投入するパワーを１００Ｗから２００Ｗへ１００Ｗも変更する必要がある。 Also, when the wavelength is around 1000 nm and the absorptance is about 2%, for example, if 2 W of absorption power is required for cutting, 100 W is input and 98 W is transmitted. For this reason, if the table is positioned below the planned cutting line through which the laser beam passes, the table is damaged by the laser beam. Therefore, a device such as making the table one size smaller than the tempered glass panel cut out from the tempered glass plate is necessary. Further, it was necessary to process the transmitted laser beam. Furthermore, since the transmittance is high, the reflected light on the end face of the tempered glass plate may have an adverse effect. Further, when the absorption rate of the laser beam is increased by the foreign matter adhering to the front surface or the back surface, the change in the absorption amount is large, which may have an adverse effect. Furthermore, even when the absorptance changes from 2% to 1% only by 1% due to the Fe concentration, it is necessary to change the input power from 100 W to 200 W by 100 W.
　これに対し、波長が３０００ｎｍ近傍で吸収率が約５０％の場合、切断に２Ｗの吸収パワーが必要であれば、４Ｗが投入され、２Ｗが透過する。このように、波長が１０００ｎｍ近傍の場合に比べ、投入パワーを劇的に減少させ、加熱効率を向上させることができる。その上、透過光も劇的に減少するので、レーザ光の通過する切断予定線の下にテーブルが位置していても、テーブルが損傷を受けることがない。そのため、切断する強化ガラス板より大きなテーブルに強化ガラスを載せることにより、より安定した状態で切断することができる。また、透過したレーザ光の処理も不要となる。さらに、強化ガラス板の端面における反射光のパワーも小さく、悪影響を及ぼし難い。また、表面あるいは裏面に付着した異物によりレーザ光の吸収率が高まっても、吸収量の変化が小さく、悪影響を及ぼし難い。さらに、Ｆｅ濃度による吸収率の変動もない上、仮に吸収率が５０％から４０％へ１０％も減少した場合でも、投入するパワーを４Ｗから５Ｗへ１Ｗだけ変更すればよい。 On the other hand, when the wavelength is around 3000 nm and the absorptance is about 50%, if 2W absorption power is required for cutting, 4W is input and 2W is transmitted. Thus, compared with the case where the wavelength is around 1000 nm, the input power can be dramatically reduced and the heating efficiency can be improved. In addition, the transmitted light also decreases dramatically, so that the table is not damaged even if the table is located below the planned cutting line through which the laser light passes. Therefore, it can cut | disconnect in a more stable state by mounting tempered glass on the table larger than the tempered glass board to cut | disconnect. Further, it is not necessary to process the transmitted laser light. Furthermore, the power of the reflected light at the end face of the tempered glass plate is also small and hardly adversely affected. Further, even if the absorption rate of the laser beam is increased due to foreign matters adhering to the front surface or the back surface, the change in the amount of absorption is small and hardly adversely affected. Further, there is no change in the absorption rate due to the Fe concentration, and even if the absorption rate is reduced from 50% to 40% by 10%, the power to be input may be changed from 4W to 5W by 1W.
　以上で説明した方法を用いることで、強化ガラス板を切断することができる。 By using the method explained above, the tempered glass plate can be cut.
＜強化ガラス板の切断方法の詳細な説明＞
　次に、本実施の形態にかかる強化ガラス板の切断方法について詳細に説明する。
　なお、上記ではレーザ光の波長として３０００ｎｍ近傍の波長が好ましいと説明したが、以下で説明する強化ガラス板の切断方法ではこの波長に限定されることはなく、例えば波長が２５０～５０００ｎｍのレーザ光について広く適用することができる。 <Detailed description of cutting method of tempered glass plate>
Next, the cutting method of the tempered glass board concerning this Embodiment is demonstrated in detail.
In the above description, the wavelength of about 3000 nm is preferable as the wavelength of the laser beam. However, the tempered glass sheet cutting method described below is not limited to this wavelength. For example, the laser beam having a wavelength of 250 to 5000 nm is used. Can be widely applied about.
　図６は、本実施の形態に係る強化ガラス板の切断方法を説明するための図である。図６は、強化ガラス板１０を上面から見た図である。また、強化ガラス板１０に示す破線は、上記で説明した切断方法を用いて、強化ガラス板１０から強化ガラスパネル４０を切り出すための切断予定線３４を示している。強化ガラスパネル４０は、所定の曲率半径Ｒを有する４つのコーナー部Ｃ１、Ｃ２、Ｃ３、Ｃ４、及び直線部４１、４２、４３、４４を有する四角形状である。なお、図６に示す強化ガラスパネル４０の形状は一例であり、他の任意の形状の強化ガラスパネル４０を強化ガラス板１０から切り出す場合にも、本実施の形態に係る強化ガラスの切断方法を用いることができる。 FIG. 6 is a diagram for explaining a method of cutting a strengthened glass sheet according to the present embodiment. FIG. 6 is a view of the tempered glass plate 10 as viewed from above. Moreover, the broken line shown in the tempered glass board 10 has shown the cutting scheduled line 34 for cutting out the tempered glass panel 40 from the tempered glass board 10 using the cutting method demonstrated above. The tempered glass panel 40 has a quadrangular shape having four corner portions C1, C2, C3, C4 having a predetermined radius of curvature R and straight portions 41, 42, 43, 44. In addition, the shape of the tempered glass panel 40 shown in FIG. 6 is an example, and when the tempered glass panel 40 having any other shape is cut out from the tempered glass plate 10, the tempered glass cutting method according to the present embodiment is used. Can be used.
　強化ガラス板１０から強化ガラスパネル４０を切り出す際は、切断予定線３４を通過するようにレーザ光を走査する。具体的には、直線部４１の延長上の端面に位置する切断開始位置４５からレーザ光の走査を開始する。そして、直線部４１、コーナー部Ｃ１、直線部４２、コーナー部Ｃ２、直線部４３、コーナー部Ｃ３、直線部４４、コーナー部Ｃ４、を経由して、コーナー部Ｃ４と直線部４１との接続点である切断終了位置４６までレーザ光を走査する。このとき、切断開始位置４５、つまり強化ガラス板１０の端部には初期クラックが予め形成されている。初期クラックは、例えばカッタ、ヤスリ、レーザで形成することができる。 When cutting the tempered glass panel 40 from the tempered glass plate 10, the laser beam is scanned so as to pass through the planned cutting line 34. Specifically, the scanning of the laser beam is started from the cutting start position 45 located on the end face on the extension of the linear portion 41. And the connection point of the corner part C4 and the straight part 41 via the straight part 41, the corner part C1, the straight part 42, the corner part C2, the straight part 43, the corner part C3, the straight part 44, and the corner part C4. The laser beam is scanned up to the cutting end position 46. At this time, initial cracks are formed in advance at the cutting start position 45, that is, at the end of the tempered glass plate 10. The initial crack can be formed by, for example, a cutter, a file, or a laser.
　このように、レーザ光を用いて強化ガラス板１０から強化ガラスパネル４０を切り出す場合、強化ガラス板１０に照射されるレーザ光の条件を最適化する必要がある。すなわち、強化ガラス板１０に照射されるレーザ光の条件が不適切な場合、切断線が切断予定線から外れ、切り出された強化ガラスパネル４０が寸法不良となるおそれがあった。 Thus, when the tempered glass panel 40 is cut out from the tempered glass plate 10 using laser light, it is necessary to optimize the conditions of the laser light applied to the tempered glass plate 10. That is, when the condition of the laser beam applied to the tempered glass plate 10 is inappropriate, the cutting line may deviate from the planned cutting line, and the tempered glass panel 40 that is cut out may be defective in dimensions.
　特に、図６に示す強化ガラスパネル４０では、所定の曲率半径Ｒを有する４つのコーナー部Ｃ１、Ｃ２、Ｃ３、Ｃ４を有する。そのため、効率（生産性）よく切断するためには、直線部４１、４２、４３、４４とコーナー部Ｃ１、Ｃ２、Ｃ３、Ｃ４とでは、照射されるレーザ光の条件を変更する必要がある。 In particular, the tempered glass panel 40 shown in FIG. 6 has four corner portions C1, C2, C3, and C4 having a predetermined radius of curvature R. Therefore, in order to cut efficiently (productivity), it is necessary to change the conditions of the irradiated laser light in the straight portions 41, 42, 43, and 44 and the corner portions C1, C2, C3, and C4.
　上述のように、強化ガラス板１０を切断する際に、レーザ光が照射されている領域に発生する圧縮応力（図４参照）を用いて、レーザ光の走査方向後方に発生する引張応力（図５参照）によるクラックの伸展をおさえながら切断している。このとき、走査方向後方に発生する引張応力によるクラックの伸展は、レーザ光の走査軌跡の接線方向に向かう性質がある。このため、コーナー部の曲率半径Ｒが小さい程（つまり、カーブが急になる程）、クラックの伸展方向を制御するのが難くなる。 As described above, when the tempered glass plate 10 is cut, a tensile stress (see FIG. 4) generated rearward in the scanning direction of the laser light using the compressive stress (see FIG. 4) generated in the region irradiated with the laser light. (Refer to 5). At this time, the extension of the crack due to the tensile stress generated backward in the scanning direction has a property of moving in the tangential direction of the scanning locus of the laser beam. For this reason, the smaller the radius of curvature R of the corner (that is, the steeper the curve), the more difficult it is to control the direction of crack extension.
　そのため、本実施の形態では、コーナー部Ｃ１、Ｃ２、Ｃ３、Ｃ４において直線部４１、４２、４３、４４よりも強化ガラス板１０に照射される単位照射面積あたりのレーザ光の照射エネルギーを大きくする。なお、曲率半径Ｒが小さい程、単位照射面積あたりのレーザ光の照射エネルギーを大きくする。 For this reason, in the present embodiment, the irradiation energy of the laser light per unit irradiation area irradiated on the tempered glass plate 10 is made larger at the corner portions C1, C2, C3, C4 than at the straight portions 41, 42, 43, 44. . The smaller the radius of curvature R is, the larger the laser beam irradiation energy per unit irradiation area is.
　単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）は、レーザ光の出力をＰ（Ｗ）、レーザ光の走査速度をｖ（ｍｍ／ｓ）、強化ガラス板１０に照射されるレーザ光のビーム径をφ（ｍｍ）とすると、次の式１で表すことができる。
　　Ｅ（Ｊ／ｍｍ２）＝Ｐ（Ｗ）／（ｖ（ｍｍ／ｓ）×φ（ｍｍ））　・・・式３ The laser beam irradiation energy E (J / mm 2 ) per unit irradiation area is applied to the tempered glass plate 10 with the laser beam output P (W) and the laser beam scanning speed v (mm / s). When the beam diameter of the laser beam is φ (mm), it can be expressed by the following formula 1.
E (J / mm 2 ) = P (W) / (v (mm / s) × φ (mm)) Equation 3
　すなわち、単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）は、レーザ光が単位時間（１秒間）に強化ガラス板１０を走査する面積あたりのエネルギーである。以下では、単位照射面積あたりのレーザ光の照射エネルギーを、単位照射エネルギーとも記載する。 That is, the irradiation energy E (J / mm 2 ) of the laser light per unit irradiation area is the energy per area where the laser light scans the tempered glass plate 10 per unit time (1 second). Hereinafter, the laser beam irradiation energy per unit irradiation area is also referred to as unit irradiation energy.
　例えば、上記の式３より、レーザ光の照射領域の移動速度（走査速度）ｖ（ｍｍ／ｓ）を遅くすることで、単位照射エネルギーＥ（Ｊ／ｍｍ２）を大きくすることができる。また、レーザ光の出力Ｐ（Ｗ）を大きくすることで、単位照射エネルギーＥ（Ｊ／ｍｍ２）を大きくすることができる。また、レーザ光の照射領域の面積（つまり、ビーム径φ）を小さくすることで、単位照射エネルギーＥ（Ｊ／ｍｍ２）を大きくすることができる。また、これら方法を適宜組み合わせることにより、単位照射エネルギーＥ（Ｊ／ｍｍ２）を大きくすることも可能である。 For example, from the above Equation 3, the unit irradiation energy E (J / mm 2 ) can be increased by slowing the moving speed (scanning speed) v (mm / s) of the laser light irradiation region. Further, the unit irradiation energy E (J / mm 2 ) can be increased by increasing the output P (W) of the laser beam. Further, the unit irradiation energy E (J / mm 2 ) can be increased by reducing the area (that is, the beam diameter φ) of the laser light irradiation region. Further, the unit irradiation energy E (J / mm 2 ) can be increased by appropriately combining these methods.
　また、強化ガラス板１０の吸収係数αが大きくなるにつれて、単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を小さくしてもよい。吸収係数αが大きい場合は、強化ガラス板１０に吸収されるエネルギーが多くなるため、その分だけ単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を小さくすることができる。 Further, as the absorption coefficient α of the tempered glass plate 10 increases, the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be decreased. When the absorption coefficient α is large, the energy absorbed by the tempered glass plate 10 increases, so that the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area can be reduced accordingly.
　また、強化ガラス板の厚さｔが厚くなるにつれて、単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を大きくしてもよい。強化ガラス板の厚さｔが厚い場合は、強化ガラス板１０に供給するエネルギーを多くする必要があるため、単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を大きくすることが好ましい。また、強化ガラス板１０の熱膨張係数が大きくなるにつれて、単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を小さくしてもよい。強化ガラス板１０の熱膨張係数が大きいとレーザ光の走査方向後方に発生する引張応力が大きくなるため、その分だけ単位照射面積あたりのレーザ光の照射エネルギーＥ（Ｊ／ｍｍ２）を小さくすることができる。 Further, the irradiation energy E (J / mm 2 ) of the laser beam per unit irradiation area may be increased as the thickness t of the tempered glass plate increases. When the thickness t of the tempered glass plate is thick, it is necessary to increase the energy supplied to the tempered glass plate 10, so that the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be increased. preferable. Further, as the thermal expansion coefficient of the tempered glass plate 10 increases, the laser beam irradiation energy E (J / mm 2 ) per unit irradiation area may be reduced. If the thermal expansion coefficient of the tempered glass plate 10 is large, the tensile stress generated behind the scanning direction of the laser beam increases, and accordingly, the irradiation energy E (J / mm 2 ) of the laser beam per unit irradiation area is reduced accordingly. be able to.
　ここで、直線部４１、４２、４３、４４において照射するレーザ光の単位照射エネルギーをＥ１とし、コーナー部Ｃ１、Ｃ２、Ｃ３、Ｃ４において照射するレーザ光の単位照射エネルギーはＥ１より大きいＥ２とする。本実施の形態では、直線部４１からコーナー部Ｃ１へ移行する際に、単位照射エネルギーをＥ１からＥ２に切り換える。一方、コーナー部Ｃ１から直線部４２へ移行する際に、単位照射エネルギーをＥ２からＥ１に切り換える。 Here, the unit irradiation energy of the laser light irradiated at the straight portions 41, 42, 43, 44 is E1, and the unit irradiation energy of the laser light irradiated at the corner portions C1, C2, C3, C4 is E2 larger than E1. . In the present embodiment, the unit irradiation energy is switched from E1 to E2 when moving from the straight line portion 41 to the corner portion C1. On the other hand, when shifting from the corner portion C1 to the linear portion 42, the unit irradiation energy is switched from E2 to E1.
　同様に、直線部４２からコーナー部Ｃ２へ移行する際に、単位照射エネルギーをＥ１からＥ２に切り換え、コーナー部Ｃ２から直線部４３へ移行する際に、単位照射エネルギーをＥ２からＥ１に切り換える。同様に、直線部４３からコーナー部Ｃ３へ移行する際に、単位照射エネルギーをＥ１からＥ２に切り換え、コーナー部Ｃ３から直線部４４へ移行する際に、単位照射エネルギーをＥ２からＥ１に切り換える。そして、直線部４４からコーナー部Ｃ４へ移行する際に、単位照射エネルギーをＥ１からＥ２に切り換える。 Similarly, the unit irradiation energy is switched from E1 to E2 when shifting from the straight line portion 42 to the corner portion C2, and the unit irradiation energy is switched from E2 to E1 when shifting from the corner portion C2 to the straight line portion 43. Similarly, the unit irradiation energy is switched from E1 to E2 when shifting from the straight line portion 43 to the corner portion C3, and the unit irradiation energy is switched from E2 to E1 when shifting from the corner portion C3 to the straight line portion 44. Then, when shifting from the straight line portion 44 to the corner portion C4, the unit irradiation energy is switched from E1 to E2.
　ここで、単位照射エネルギーＥ１、Ｅ２の切り換えは、生産性を考えた場合、できる限り短時間で行うことが好ましい。
　しかしながら、発明者は、コーナー部から直線部への移行点（つまり、コーナー部出口）において、高い単位照射エネルギーＥ２から低い単位照射エネルギーＥ１へ急激に切り換えると、切断線が切断予定線３４から外側へはみ出し、切り出された強化ガラスパネル４０が寸法不良となるおそれがあることを見出した。 Here, switching of the unit irradiation energies E1 and E2 is preferably performed in as short a time as possible in view of productivity.
However, when the inventor suddenly switches from the high unit irradiation energy E2 to the low unit irradiation energy E1 at the transition point from the corner portion to the straight portion (that is, the corner portion exit), the cutting line is outside the planned cutting line 34. The present inventors have found that the tempered glass panel 40 that protrudes and cuts out may be defective in dimensions.
　鋭意研究の結果、発明者は、コーナー部から直線部への移行点における単位照射エネルギーの切換速度を制限する（低く抑える）ことにより、切断予定線３４からのずれ量（つまり寸法誤差）を抑制できることを見出した。ここで、単位照射エネルギーの切換速度とは、単位時間当たりの単位照射エネルギーの変化量である。つまり、単位照射エネルギーの変化量をΔＥ（＝Ｅ２－Ｅ１）、その切り換えに要する時間をＴとすると、単位照射エネルギーの切換速度はΔＥ／Ｔと表すことができる。 As a result of earnest research, the inventor suppresses the deviation amount (that is, dimensional error) from the planned cutting line 34 by restricting (lowering) the switching speed of the unit irradiation energy at the transition point from the corner portion to the straight portion. I found out that I can do it. Here, the switching speed of the unit irradiation energy is a change amount of the unit irradiation energy per unit time. That is, if the change amount of the unit irradiation energy is ΔE (= E2−E1) and the time required for switching is T, the switching speed of the unit irradiation energy can be expressed as ΔE / T.
　そこで、本実施の形態に係る強化ガラス板１０の切断方法では、コーナー部から直線部への移行点（コーナー部の出口）における単位照射エネルギーＥの切換速度を低く抑えている。これにより、切断予定線３４からのずれ量を抑制することができる。図７は、直線部とコーナー部とにおける単位照射エネルギーＥの切り替えを模式的に示したグラフである。横軸は時間、縦軸は単位照射エネルギーＥ（Ｊ／ｍｍ２）である。 Therefore, in the method for cutting the tempered glass plate 10 according to the present embodiment, the switching speed of the unit irradiation energy E at the transition point from the corner portion to the straight portion (exit of the corner portion) is kept low. Thereby, the deviation | shift amount from the cutting projected line 34 can be suppressed. FIG. 7 is a graph schematically showing switching of the unit irradiation energy E between the straight line portion and the corner portion. The horizontal axis represents time, and the vertical axis represents unit irradiation energy E (J / mm 2 ).
　ここで、直線部からコーナー部への移行点（つまり、コーナー部入口）では上記はみ出しの問題は生じないから、図７に示すように、このポイントにおける単位照射エネルギーの切換速度は、速い程好ましい。従って、本実施の形態に係る強化ガラスの切断方法では、コーナー部出口における単位照射エネルギーの切換速度は、コーナー部入口における単位照射エネルギーの切換速度よりも小さくする。また、図７のグラフおいて実線で示すように、コーナー部の出口における単位照射エネルギーの切換速度ΔＥ／Ｔは、一定とするよりもできる限り滑らかに変化させる（徐々に上昇させる）ことが好ましい。これにより、切断予定線３４からのずれ量をさらに抑制することができる。 Here, at the transition point from the straight line portion to the corner portion (that is, the corner portion entrance), the problem of the above-mentioned protrusion does not occur. Therefore, as shown in FIG. 7, the unit irradiation energy switching speed at this point is preferably as fast as possible. . Therefore, in the method for cutting tempered glass according to the present embodiment, the unit irradiation energy switching speed at the corner portion outlet is set to be lower than the unit irradiation energy switching speed at the corner portion entrance. Further, as indicated by a solid line in the graph of FIG. 7, it is preferable that the switching speed ΔE / T of the unit irradiation energy at the exit of the corner portion is changed as smoothly as possible (gradual increase) rather than being constant. . Thereby, the deviation | shift amount from the cutting projected line 34 can further be suppressed.
　さらに、発明者は、強化ガラス板１０の残留引張応力ＣＴが小さい程、単位照射エネルギーの切換速度を低く抑える必要があることを見出した。そこで、本実施の形態に係る強化ガラスの切断方法では、強化ガラス板１０の残留引張応力ＣＴが小さい程、単位照射エネルギーの切換速度を低く抑えている。 Furthermore, the inventor has found that the switching speed of the unit irradiation energy needs to be kept lower as the residual tensile stress CT of the tempered glass plate 10 is smaller. Therefore, in the method for cutting tempered glass according to the present embodiment, the unit irradiation energy switching speed is kept lower as the residual tensile stress CT of the tempered glass plate 10 is smaller.
　以上で説明した本実施の形態に係る強化ガラスの切断方法により、高い生産性を維持しつつ、切り出された強化ガラスパネルの寸法不良を抑制することができる。 With the method for cutting tempered glass according to the present embodiment described above, it is possible to suppress dimensional defects of the cut out tempered glass panel while maintaining high productivity.
＜参考例１＞
　ここで、図８～１０を参照して、強化ガラス板の切断方法と非強化ガラス板の切断方法とでは、クラックの伸展の仕方が異なることについて説明する。図８は、強化ガラス板についての切断結果を示す表である。図９は、非強化ガラス板についての切断結果を示す表である。図１０は、強化ガラス板（参考例）及び非強化ガラス板（比較例）についての切断結果を示す表である。図１０に示す切断結果は、図８、図９に示した切断結果よりもレーザ光のスポット径を小さくした場合の切断結果である。 <Reference Example 1>
Here, with reference to FIGS. 8 to 10, it will be described that the method of extending the cracks differs between the cutting method of the tempered glass plate and the cutting method of the non-tempered glass plate. FIG. 8 is a table showing the cutting results for the tempered glass sheet. FIG. 9 is a table showing the cutting results for the non-tempered glass sheet. FIG. 10 is a table showing cutting results for a tempered glass plate (reference example) and a non-tempered glass plate (comparative example). The cutting results shown in FIG. 10 are cutting results when the spot diameter of the laser beam is made smaller than the cutting results shown in FIGS.
　参考例１０１～１０３、１０６～１０８では強化ガラス板を用意し、比較例１０４～１０５、１０９～１１０では非強化ガラス板を用意した。参考例１０１～１０３、１０６～１０８の強化ガラス板は、比較例１０４～１０５、１０９～１１０の非強化ガラス板と同じ寸法形状（矩形、長辺１００ｍｍ、短辺６０ｍｍ、板厚０．７ｍｍ）、同じ化学組成のガラス板を化学強化法で強化して作製した。強化ガラス板は、内部残留引張応力（ＣＴ）３０．４ＭＰａ、最大残留圧縮応力（ＣＳ）７６３ＭＰａ、圧縮応力層（表面層や裏面層）の厚さ（ＤＯＬ）２５．８μｍを有していた。ここで、内部ひずみエネルギーＵＣＴは４．０４Ｊ／ｍ２であった。 In Reference Examples 101 to 103 and 106 to 108, a tempered glass plate was prepared, and in Comparative Examples 104 to 105 and 109 to 110, a non-tempered glass plate was prepared. The tempered glass plates of Reference Examples 101 to 103 and 106 to 108 have the same size and shape as the non-tempered glass plates of Comparative Examples 104 to 105 and 109 to 110 (rectangle, long side 100 mm, short side 60 mm, plate thickness 0.7 mm). A glass plate having the same chemical composition was reinforced by a chemical strengthening method. The tempered glass plate had an internal residual tensile stress (CT) of 30.4 MPa, a maximum residual compressive stress (CS) of 763 MPa, and a thickness (DOL) of the compressive stress layer (surface layer or back surface layer) of 25.8 μm. Here, the internal strain energy U CT was 4.04 J / m 2 .
　参考例１０１～１０３、１０６～１０８、比較例１０４～１０５、１０９～１１０では、ガラス板の種類（強化、非強化の別）、光源の出力、及びレーザスポット径以外、同じ条件下で切断実験を行った。
＜共通の条件＞
　レーザ光光源：ファイバーレーザ（波長１０７０ｎｍ）
　レーザ光のガラス板への入射角：０°
　レーザ光の集光角：２．５°
　レーザ光の集光位置：ガラス板の表面から光源側に２３ｍｍ離れた位置
　ガラス板の表面におけるレーザスポット径：φ１ｍｍ
　レーザ光に対するガラス板の吸収係数α：０．０９ｃｍ－１（０．００９ｍｍ－１）
　ガラス板の板厚ｔ：０．０７ｃｍ（０．７ｍｍ）
　ガラス板のヤング率Ｙ：７４０００ＭＰａ
　α×ｔ：０．００６３
　ノズルの出口径：φ１ｍｍ
　ノズルからの冷却ガス（室温の圧縮空気）の流量：３０Ｌ／ｍｉｎ
　目標切断位置：ガラス板の短辺と平行な直線（一方の短辺からの距離１０ｍｍ、他方の短辺からの距離９０ｍｍ）
　切断速度：２．５ｍｍ／ｓ In Reference Examples 101 to 103, 106 to 108, and Comparative Examples 104 to 105 and 109 to 110, cutting experiments were performed under the same conditions except for the type of glass plate (strengthening or non-strengthening), light source output, and laser spot diameter. Went.
<Common conditions>
Laser light source: Fiber laser (wavelength 1070 nm)
Incident angle of laser beam to glass plate: 0 °
Condensing angle of laser beam: 2.5 °
Laser beam condensing position: position 23 mm away from the surface of the glass plate toward the light source side Laser spot diameter on the surface of the glass plate: φ1 mm
Absorption coefficient α of the glass plate with respect to laser light: 0.09 cm −1 (0.009 mm −1 )
Thickness t of glass plate: 0.07 cm (0.7 mm)
Young's modulus Y of glass plate: 74000 MPa
α × t: 0.0063
Nozzle outlet diameter: φ1mm
Flow rate of cooling gas (room temperature compressed air) from the nozzle: 30 L / min
Target cutting position: A straight line parallel to the short side of the glass plate (distance 10 mm from one short side, distance 90 mm from the other short side)
Cutting speed: 2.5 mm / s
　図８、図９に示す参考例１０１～１０３及び比較例１０４～１０５では、ガラス板の表面におけるレーザスポット径φを１ｍｍとした。また、図１０に示す参考例１０６～１０８及び比較例１０９～１１０では、ガラス板の表面におけるレーザスポット径φを０．１ｍｍとした。 In Reference Examples 101 to 103 and Comparative Examples 104 to 105 shown in FIGS. 8 and 9, the laser spot diameter φ on the surface of the glass plate was set to 1 mm. In Reference Examples 106 to 108 and Comparative Examples 109 to 110 shown in FIG. 10, the laser spot diameter φ on the surface of the glass plate was set to 0.1 mm.
　切断後、ガラス板の切断面を顕微鏡で観察した。ガラス板の切断面で観察される縞模様は、断続的に伸展するクラックの先端位置の経時変化を表す。縞模様の各線の形状から、クラックの伸展の様子がわかる。図８～１０に示す顕微鏡写真において、縞模様の代表的な線を太い白線で強調表示する。
　また、ガラス板の切断の途中で、レーザ照射及びガス冷却を中断したときのクラックの様子を目視で観察した。 After cutting, the cut surface of the glass plate was observed with a microscope. The striped pattern observed on the cut surface of the glass plate represents a change with time of the tip position of the intermittently extending crack. From the shape of each striped line, you can see how the cracks extend. In the micrographs shown in FIGS. 8 to 10, representative lines of the stripe pattern are highlighted with thick white lines.
Moreover, the state of the crack when laser irradiation and gas cooling were interrupted during the cutting of the glass plate was visually observed.
　各実験結果を図８～１０に示す。図８～１０において、ガラス板にクラックが形成された場合（切断できた場合）を「○」、ガラス板にクラックが形成されなかった場合（切断できなかった場合）を「×」として示した。
　図８～１０の切断面の顕微鏡写真における縞模様の線は、ある時点でのクラックの先端位置を表す。
　図８～１０における「自走」とは、レーザ照射等の中断後に、ガラス板の２つの短辺のうち、切断位置から近い方の短辺に向けてクラックが伸展することを意味する。 The results of each experiment are shown in FIGS. 8 to 10, the case where a crack was formed on the glass plate (when it was cut) was shown as “◯”, and the case where no crack was formed on the glass plate (when it was not cut) was shown as “x”. .
The striped line in the micrographs of the cut planes of FIGS. 8 to 10 represents the tip position of the crack at a certain point.
“Self-propelled” in FIGS. 8 to 10 means that, after interruption of laser irradiation or the like, the crack extends toward the shorter side closer to the cutting position among the two shorter sides of the glass plate.
　凸量、及び直線誤差量は、ガラス板を切断した際の誤差量を示している。つまり、ガラス板を上面側から見た際に、ガラス板の切断線が切断予定線（グラフのＸ軸で示す）からずれている量（グラフのＹ軸で示す）を示している。凸量、及び直線誤差量（つまり、Ｙ軸の絶対値）が小さいほど、ガラス板が切断予定線に沿って切断されている。 The convex amount and the straight line error amount indicate the error amount when the glass plate is cut. That is, it shows the amount (indicated by the Y axis of the graph) that the cutting line of the glass plate deviates from the planned cutting line (indicated by the X axis of the graph) when the glass plate is viewed from the upper surface side. The smaller the convex amount and the linear error amount (that is, the absolute value of the Y axis), the more the glass plate is cut along the planned cutting line.
　図９に示すように、比較例１０４～１０５に係る非強化ガラス板の切断では、切断面の顕微鏡写真から明らかなように、ガラス板の板厚方向両端部が、ガラス板の板厚方向中央部よりも先に割れる傾向にあった。また、切断の途中でレーザ照射及びガス冷却を中断すると、クラックの伸展が停止した。また、非強化ガラスの切断では、大きな光源出力が必要であった。更に、非強化ガラス板の切断では、凸量、及び直線誤差量が大きくなった。 As shown in FIG. 9, in the cutting of the non-strengthened glass plates according to Comparative Examples 104 to 105, as apparent from the micrograph of the cut surface, both end portions in the thickness direction of the glass plate are in the center in the thickness direction of the glass plate. There was a tendency to break before the club. Further, when laser irradiation and gas cooling were interrupted during cutting, the extension of cracks was stopped. Moreover, in the cutting | disconnection of non-tempered glass, the big light source output was required. Furthermore, in the cutting of the non-tempered glass plate, the convex amount and the linear error amount increased.
　これに対し、図８に示す参考例１０１～１０３に係る強化ガラス板の切断では、切断面の顕微鏡写真から明らかなように、ガラス板の板厚方向中央部が、ガラス板の板厚方向両端部よりも先に割れる傾向にあった。これは、元々強化ガラス板の内部に残留引張応力が存在しており、この残留引張応力によってクラックが伸展するためである。また、切断の途中でレーザ照射及びガス冷却を中断すると、クラックが意図しない方向に自ら伸展した。この結果から、レーザ光の照射により、残留引張応力によるクラックの伸展が抑制されていることが分かる。また、強化ガラス板の切断では、凸量、及び直線誤差量が非強化ガラス板の切断の場合よりも小さかった。図１０に示す参考例１０６～１０８に係る強化ガラス板の切断においても同様の結果となった。 On the other hand, in the cutting of the tempered glass plates according to Reference Examples 101 to 103 shown in FIG. 8, as is clear from the micrographs of the cut surfaces, the center portions in the thickness direction of the glass plates are at both ends in the thickness direction of the glass plates. There was a tendency to break before the club. This is because a residual tensile stress originally exists inside the tempered glass plate, and cracks extend due to this residual tensile stress. Moreover, when laser irradiation and gas cooling were interrupted in the middle of cutting, the crack extended itself in an unintended direction. From this result, it can be seen that the extension of cracks due to the residual tensile stress is suppressed by the irradiation of the laser beam. Moreover, in the cutting | disconnection of the tempered glass board, the convex amount and the amount of linear errors were smaller than the case of the cutting | disconnection of a non-tempered glass board. Similar results were obtained when cutting the tempered glass sheets according to Reference Examples 106 to 108 shown in FIG.
　また、図１０に示すように、レーザスポット径を小さくした場合（参考例１０６～１０８）は、参考例１０１～１０３よりも小さい光源出力で強化ガラス板を切断することができた。また、参考例１０６～１０８では、図８に示す参考例１０１～１０３と比べて凸量、及び直線誤差量が小さくなった。つまり、参考例１０６～１０８では、参考例１０１～１０３よりも精度よく強化ガラス板を切断することができた。また、参考例１０６～１０８に示すように、光源出力を低くするほど、凸量、及び直線誤差量が小さくなった。特に参考例１０８では、凸量が１５μｍと非常に小さい値となった。 Further, as shown in FIG. 10, when the laser spot diameter was reduced (Reference Examples 106 to 108), the tempered glass plate could be cut with a light source output smaller than that of Reference Examples 101 to 103. Further, in Reference Examples 106 to 108, the convex amount and the linear error amount were smaller than those in Reference Examples 101 to 103 shown in FIG. That is, in Reference Examples 106 to 108, the tempered glass plate could be cut with higher accuracy than Reference Examples 101 to 103. Further, as shown in Reference Examples 106 to 108, as the light source output was lowered, the convex amount and the linear error amount were reduced. Particularly in Reference Example 108, the convex amount was as small as 15 μm.
　一方、レーザスポット径を小さくした場合は、非強化ガラス板を切断することができなかった。つまり、比較例１０９に示すように、光源の出力を２００Ｗとした場合は非強化ガラス板が溶融し、切断することができなかった。すなわち、非強化ガラスの温度が徐冷点以上になり切断できなかった。また、比較例１１０に示すように、光源の出力を１００Ｗとした場合は非強化ガラス板に変化がなかった。よって、レーザスポット径を小さく（例えば、板厚未満）した場合は、光源の出力によらずに非強化ガラス板を切断できなかった。 On the other hand, when the laser spot diameter was reduced, the non-tempered glass plate could not be cut. That is, as shown in Comparative Example 109, when the output of the light source was 200 W, the non-tempered glass plate was melted and could not be cut. That is, the temperature of the non-tempered glass was not lower than the annealing point and could not be cut. Further, as shown in Comparative Example 110, when the output of the light source was 100 W, there was no change in the non-tempered glass plate. Therefore, when the laser spot diameter was reduced (for example, less than the plate thickness), the non-tempered glass plate could not be cut regardless of the output of the light source.
　このように、強化ガラス板の切断方法と非強化ガラス板の切断方法とでは、切断のメカニズムが根本的に異なり、クラックの伸展の仕方が全く異なる。そのため、本発明では、非強化ガラス板の切断方法からは予測できない効果が得られる。その理由を以下に説明する。 Thus, the cutting mechanism is fundamentally different between the method of cutting a tempered glass plate and the method of cutting a non-tempered glass plate, and the method of extending cracks is completely different. Therefore, in this invention, the effect which cannot be estimated from the cutting method of a non-tempered glass board is acquired. The reason will be described below.
　例えば、非強化ガラス板の切断方法では、レーザ光と冷却液の両方を用いてガラス板に熱応力場を形成し、切断に必要な引張応力を発生させる。より具体的には、レーザ光をガラス板に照射してガラス板内部に熱応力を発生させ、その熱応力により生じた圧縮応力を冷却液で急冷して、引張応力を発生させてクラックを伸展させる。従って、クラックの伸展は、レーザ光の照射エネルギーのみで行われ、ガラス板に照射するレーザのパワー（Ｗ）を大きく設定する必要がある。 For example, in the method of cutting a non-strengthened glass plate, a thermal stress field is formed on the glass plate using both a laser beam and a cooling liquid to generate a tensile stress necessary for cutting. More specifically, the glass plate is irradiated with laser light to generate thermal stress inside the glass plate, and the compressive stress generated by the thermal stress is quenched with a cooling liquid to generate tensile stress and extend cracks. Let Therefore, the extension of the crack is performed only by the irradiation energy of the laser beam, and it is necessary to set a large power (W) of the laser irradiated to the glass plate.
　このような方法では、ガラス板に形成される割断亀裂の先端位置は、ガラス板を冷却する冷却液の位置で決まる。冷却液の位置に引張応力が生じるためである。従って、切断の途中で、レーザ光による加熱や冷却液による冷却を中断すると、クラックの伸展が止まる。 In such a method, the tip position of the cleaving crack formed in the glass plate is determined by the position of the coolant that cools the glass plate. This is because tensile stress is generated at the position of the coolant. Therefore, if heating with laser light or cooling with a coolant is interrupted during cutting, the extension of cracks stops.
　図１１は、レーザ光を用いて非強化ガラス板を切断する際に作用する応力を説明するための図である。図１１では非強化ガラス板１１０の上面図と、非強化ガラス板１１０の板厚中心部に発生する応力の分布を示している。図１１に示すように、非強化ガラス板１１０にレーザ光を照射すると、レーザ光の照射領域１２２に圧縮応力１３３が働く。この圧縮応力１３３は、レーザ光の照射により発生する熱応力である。そして、この圧縮応力１３３と釣り合うように、照射領域１２２の走査方向後方に引張応力１３５が発生する。この引張応力１３５がクラック１３０に作用することで非強化ガラス板１１０が切断される。 FIG. 11 is a diagram for explaining the stress that acts when cutting a non-tempered glass plate using a laser beam. FIG. 11 shows a top view of the non-tempered glass plate 110 and a distribution of stress generated at the center of the thickness of the non-tempered glass plate 110. As shown in FIG. 11, when the non-strengthened glass plate 110 is irradiated with laser light, a compressive stress 133 acts on the laser light irradiation region 122. This compressive stress 133 is a thermal stress generated by laser light irradiation. A tensile stress 135 is generated behind the irradiation region 122 in the scanning direction so as to balance with the compressive stress 133. The non-tempered glass plate 110 is cut by the tensile stress 135 acting on the crack 130.
　図１１のグラフに示すように、非強化ガラス板１１０では内部残留引張応力ＣＴは略ゼロである。このため、非強化ガラス板１１０を切断する際にクラック１３０に作用する引張応力１３５は、レーザ光の照射によってのみ発生する。よって、引張応力１３５を大きくするために、レーザ光の照射エネルギーを高くしたり、レーザスポット径を大きくしたりする必要がある。このため、非強化ガラス板１１０では、レーザ光の吸収率が小さいガラスでは切断が困難となる。 As shown in the graph of FIG. 11, in the non-tempered glass plate 110, the internal residual tensile stress CT is substantially zero. For this reason, the tensile stress 135 which acts on the crack 130 when cutting the non-tempered glass plate 110 is generated only by laser light irradiation. Therefore, in order to increase the tensile stress 135, it is necessary to increase the irradiation energy of the laser beam or increase the laser spot diameter. For this reason, in the non-tempered glass plate 110, it becomes difficult to cut with glass having a low absorption rate of laser light.
　また、非強化ガラス板１１０を切断する際は、レーザ光の照射エネルギーと走査速度でクラックの伸展を制御している。このとき、レーザ光の照射エネルギーが、切断に必要な照射エネルギーよりも小さいとクラックの伸展が停止する。つまり、図１１のグラフに示すように、クラック１３０を伸展させるためには、クラック１３０の伸展に必要な引張応力Ｓ_ｔｈよりも大きな引張応力をクラック１３０に作用させる必要がある。非強化ガラス板１１０では内部残留引張応力ＣＴが略ゼロであるため、レーザ光の照射エネルギーのみでこの引張応力Ｓ_ｔｈの値よりも大きな引張応力を発生させる必要がある。 Further, when cutting the non-tempered glass plate 110, the extension of cracks is controlled by the irradiation energy of the laser beam and the scanning speed. At this time, if the irradiation energy of the laser beam is smaller than the irradiation energy necessary for cutting, the extension of the crack is stopped. That is, as shown in the graph of FIG. 11, in order to extend the crack 130, it is necessary to apply a tensile stress larger than the tensile stress S_th necessary for the extension of the crack 130 to the crack 130. Since the internal residual tensile stress CT is substantially zero in the non-tempered glass plate 110, it is necessary to generate a tensile stress larger than the value of the tensile stress S_th only with the laser beam irradiation energy.
　これに対し、強化ガラス板の切断方法では、元々ガラス板内部に内部残留引張応力が存在するため、非強化ガラス板の切断の場合のように、レーザ光の照射エネルギーのみで大きな引張応力を発生させる必要がない。また、内部残留引張応力がクラックの伸展に必要な引張応力Ｓ_ｔｈよりも大きな引張応力の場合、強化ガラス板に何らかの力を作用させてクラックを発生させると、内部残留引張応力のためにクラックは自ら伸展する。他方、内部残留引張応力はガラス板内部に全体的に存在しているので、クラックの伸展を制御しない限り、クラックが意図しない方向に伸展してしまう。 On the other hand, in the cutting method of tempered glass plate, internal residual tensile stress originally exists inside the glass plate, so a large tensile stress is generated only by the irradiation energy of laser light as in the case of cutting non-tempered glass plate. There is no need to let them. Also, if the internal residual tensile stress is larger than the tensile stress S_th required for the extension of the crack, if the crack is generated by applying some force to the tempered glass sheet, the crack will be self-generated due to the internal residual tensile stress. Extend. On the other hand, since the internal residual tensile stress exists entirely inside the glass plate, unless the crack extension is controlled, the crack extends in an unintended direction.
　そのため、本発明では、照射領域の中心における中間層に内部残留引張応力の値よりも小さい引張応力、または、圧縮応力を発生させ、内部残留引張応力によるクラックの伸展を抑制している。即ち、レーザ光を照射することにより強化ガラス板の中間層における残留引張応力をクラックの伸展に必要な引張応力Ｓ_ｔｈよりも小さくして、クラックの伸展を制御している。 Therefore, in the present invention, a tensile stress smaller than the value of the internal residual tensile stress or a compressive stress is generated in the intermediate layer at the center of the irradiation region, thereby suppressing the extension of cracks due to the internal residual tensile stress. That is, the extension of the crack is controlled by irradiating the laser beam so that the residual tensile stress in the intermediate layer of the tempered glass plate is made smaller than the tensile stress S_th necessary for the extension of the crack.
　図１２は、レーザ光を用いて強化ガラス板を切断する際に作用する応力の一例を示す図である。図１２では強化ガラス板１０の上面図と、強化ガラス板１０の板厚中心部に発生する応力の分布を示している。図１２に示すように、強化ガラス板１０にレーザ光を照射すると、レーザ光の照射領域２２に圧縮応力３３が働く。また、照射領域２２の走査方向後方に引張応力３５が発生する。そして、この引張応力３５に内部残留引張応力が加算される事でクラックの伸展に必要な引張応力Ｓ_ｔｈよりも大きな引張応力が発生し、クラック３０に作用することで強化ガラス板１０が切断される。このとき、圧縮応力３３によってクラック３０の伸展が制御される。 FIG. 12 is a diagram showing an example of stress acting when a tempered glass plate is cut using a laser beam. FIG. 12 shows a top view of the tempered glass plate 10 and a distribution of stresses generated at the central portion of the thickness of the tempered glass plate 10. As shown in FIG. 12, when the tempered glass plate 10 is irradiated with laser light, a compressive stress 33 acts on the laser light irradiation region 22. Further, a tensile stress 35 is generated behind the irradiation region 22 in the scanning direction. Then, the internal residual tensile stress is added to the tensile stress 35 to generate a tensile stress larger than the tensile stress S_th necessary for the extension of the crack, and the tempered glass sheet 10 is cut by acting on the crack 30. . At this time, extension of the crack 30 is controlled by the compressive stress 33.
　図１２のグラフに示すように、強化ガラス板１０には内部残留引張応力ＣＴが存在する。このため、クラック３０の伸展に必要な引張応力３５は小さくてすむ。換言すると、引張応力Ｓ_ｔｈ（クラック３０の伸展に必要な引張応力）よりも大きな引張応力をクラック３０に作用させるために必要なレーザ光により発生させる圧縮応力３３を小さくすることができる。 As shown in the graph of FIG. 12, the tempered glass plate 10 has an internal residual tensile stress CT. For this reason, the tensile stress 35 required for the extension of the crack 30 can be small. In other words, it is possible to reduce the compressive stress 33 generated by the laser beam necessary for causing the tensile stress larger than the tensile stress S_th (the tensile stress necessary for the extension of the crack 30) to act on the crack 30.
　ここで、強化ガラス板１０を切断する際に必要な圧縮応力３３や引張応力３５は、非強化ガラス１１０を切断する際に必要な応力よりも小さくすることができるため、レーザ光の照射エネルギーを小さくしたり、レーザスポット径を小さくしたりすることができる。このため、切断精度を向上させることができる。また、レーザ光の吸収率が小さいガラスであっても容易に切断することができる。 Here, since the compressive stress 33 and the tensile stress 35 required when cutting the tempered glass plate 10 can be made smaller than the stress required when cutting the non-tempered glass 110, the irradiation energy of the laser beam is reduced. The laser spot diameter can be reduced or the laser spot diameter can be reduced. For this reason, cutting accuracy can be improved. Further, even glass having a low absorption rate of laser light can be easily cut.
　図１３は、レーザ光を用いて強化ガラス板を切断する際に作用する応力の他の例を示す図である。図１３では強化ガラス板１０の上面図と、強化ガラス板１０の板厚中心部に発生する応力の分布を示している。図１３に示す強化ガラス板１０では、内部残留引張応力ＣＴが、クラック３０の伸展に必要な引張応力Ｓ_ｔｈよりも大きい。つまり、図１３に示すように、強化ガラス板１０にレーザ光を照射すると、レーザ光の照射領域２２には内部残留引張応力ＣＴの値よりも小さい引張応力３７が発生する。ここで、引張応力３７は、レーザ光の照射により発生した圧縮応力３３と内部残留引張応力ＣＴとの合力である。また、照射領域２２の走査方向後方には引張応力３５が発生する。この場合は、内部残留引張応力ＣＴの値よりも小さい引張応力３７を、クラック３０の伸展に必要な引張応力Ｓ_ｔｈよりも小さくすることで、クラック３０の伸展を抑えることができる。 FIG. 13 is a diagram showing another example of stress acting when a tempered glass plate is cut using a laser beam. FIG. 13 shows a top view of the tempered glass plate 10 and a distribution of stresses generated at the central portion of the thickness of the tempered glass plate 10. In the tempered glass plate 10 shown in FIG. 13, the internal residual tensile stress CT is larger than the tensile stress S_th necessary for the extension of the crack 30. That is, as shown in FIG. 13, when the tempered glass plate 10 is irradiated with laser light, a tensile stress 37 smaller than the value of the internal residual tensile stress CT is generated in the laser light irradiation region 22. Here, the tensile stress 37 is a resultant force of the compressive stress 33 generated by the laser light irradiation and the internal residual tensile stress CT. Further, a tensile stress 35 is generated behind the irradiation region 22 in the scanning direction. In this case, the extension of the crack 30 can be suppressed by making the tensile stress 37 smaller than the value of the internal residual tensile stress CT smaller than the tensile stress S_th necessary for the extension of the crack 30.
　図１３に示す場合も、強化ガラス板１０を切断する際に必要な、内部残留引張応力ＣＴの値よりも小さい引張応力３７や引張応力３５は、非強化ガラス１１０を切断する際に必要な応力よりも小さくすることができるため、レーザ光の照射エネルギーを小さくしたり、レーザスポット径を小さくしたりすることができる。このため、切断精度を向上させることができる。また、レーザ光の吸収率が小さいガラスであっても容易に切断することができる。 Also in the case shown in FIG. 13, the tensile stress 37 and the tensile stress 35 smaller than the value of the internal residual tensile stress CT required when cutting the tempered glass plate 10 are stresses required when cutting the non-tempered glass 110. Therefore, the irradiation energy of laser light can be reduced, and the laser spot diameter can be reduced. For this reason, cutting accuracy can be improved. Further, even glass having a low absorption rate of laser light can be easily cut.
　上記で説明したように、強化ガラス板１０を切断する際は、内部残留引張応力ＣＴとレーザ光の照射エネルギーと走査速度のバランスを保つことで、クラック３０を自走させることなくクラック３０の伸展を制御している。よって、レーザ光の照射エネルギーが小さすぎると、内部残留引張応力ＣＴの値よりも小さい引張応力３７がクラック３０の伸展に必要な引張応力Ｓ_ｔｈよりも大きくなり、クラック３０の伸展は止まらずに自走する（図１３の場合）。 As described above, when the tempered glass plate 10 is cut, by maintaining a balance between the internal residual tensile stress CT, the irradiation energy of the laser beam, and the scanning speed, the extension of the crack 30 without causing the crack 30 to self-run. Is controlling. Therefore, if the laser beam irradiation energy is too small, the tensile stress 37 smaller than the value of the internal residual tensile stress CT becomes larger than the tensile stress S_th required for the extension of the crack 30, and the extension of the crack 30 does not stop. Run (in the case of FIG. 13).
　このように、強化ガラス板の切断方法と非強化ガラス板の切断方法とでは、切断のメカニズムが根本的に異なり、クラックの伸展の仕方が全く異なる。そのため、本発明では、非強化ガラス板の切断方法からは予測できない効果が得られる。 Thus, the cutting mechanism is fundamentally different between the method of cutting a tempered glass plate and the method of cutting a non-tempered glass plate, and the method of extending cracks is completely different. Therefore, in this invention, the effect which cannot be estimated from the cutting method of a non-tempered glass board is acquired.
＜参考例２＞
　次に、参考例２について説明する。参考例２では、内部ひずみエネルギーＵＣＴと切断可能な照射エネルギーＥＬの最小値である臨界照射エネルギーＥｃとの関係について説明する。 <Reference Example 2>
Next, Reference Example 2 will be described. In Reference Example 2, a description will be given of the relationship between the critical irradiation energy Ec is the minimum value of the internal strain energy U CT and cleavable irradiation energy E L.
　参考例２では、内部ひずみエネルギーＵＣＴが異なる２１個のサンプル１～２１について、臨界照射エネルギーＥｃとの関係を調査した。なお、サンプル１８～２１は、非強化ガラス板である。
　図１４は、参考例２に係る切断予定線の形状を示す図である。図１４に示すように、参考例２に係る切断予定線は、２つの直線部と、クランク形状を構成する２つのコーナー部（曲率半径Ｒ＝５ｍｍ）を備えている。 In Reference Example 2, the internal strain energy U CT is for different 21 samples 1-21 were investigated the relationship between the critical irradiation energy Ec. Samples 18 to 21 are non-tempered glass plates.
FIG. 14 is a diagram illustrating the shape of a planned cutting line according to Reference Example 2. As shown in FIG. 14, the planned cutting line according to the reference example 2 includes two straight portions and two corner portions (curvature radius R = 5 mm) constituting the crank shape.
　化学強化用のガラス板として、複数種類の原料を混ぜて調整したガラス原料を溶解し、溶解した溶融ガラスを板状に成形した。これを室温付近まで徐冷した後、切断、切削、両面鏡面研磨することにより、所定の厚さを有する５０ｍｍ×５０ｍｍのガラス板を作製した。ガラス原料は、ガラス板のレーザ光に対する吸収係数αが所望の値となるように、同じ配合比のベース材に対する酸化鉄（Ｆｅ２Ｏ３）の粉末の添加量を変えて調製した。 As a glass plate for chemical strengthening, a glass raw material prepared by mixing a plurality of types of raw materials was melted, and the melted molten glass was formed into a plate shape. This was gradually cooled to near room temperature, and then cut, cut, and polished on both sides to prepare a 50 mm × 50 mm glass plate having a predetermined thickness. The glass raw material was prepared by changing the amount of iron oxide (Fe 2 O 3 ) powder added to the base material having the same blending ratio so that the absorption coefficient α of the glass plate with respect to the laser beam became a desired value.
　各化学強化用ガラス板は、酸化物基準の質量％表示で、ＳｉＯ２：６０．９％、Ａｌ２Ｏ３：１２．８％、Ｎａ２Ｏ：１２．２％、Ｋ２Ｏ：５．９％、ＭｇＯ：６．７％、ＣａＯ：０．１％、ＳｒＯ：０．２％、ＢａＯ：０．２％、ＺｒＯ２：１．０％を含有しており、酸化鉄（Ｆｅ２Ｏ３）を外割りで所定量含有していた。 Each glass sheet for chemical strengthening is expressed in terms of mass% based on oxide, SiO 2 : 60.9%, Al 2 O 3 : 12.8%, Na 2 O: 12.2%, K 2 O: 5. 9%, MgO: 6.7%, CaO: 0.1%, SrO: 0.2%, BaO: 0.2%, ZrO 2 : 1.0%, and iron oxide (Fe 2 O 3 ) was contained in a predetermined amount by external division.
　各強化ガラス板は、上記の化学強化用ガラス板をＫＮＯ３溶融塩に浸漬し、イオン交換処理した後、室温付近まで冷却することにより作製した。ＫＮＯ３溶融塩の温度や浸漬時間などの処理条件は、内部残留引張応力ＣＴが所望の値となるように設定した。 Each tempered glass plate was prepared by immersing the above-described glass plate for chemical strengthening in KNO 3 molten salt, performing an ion exchange treatment, and then cooling to near room temperature. The treatment conditions such as the temperature and immersion time of the KNO 3 molten salt were set so that the internal residual tensile stress CT had a desired value.
　強化ガラス板の内部残留引張応力ＣＴ（ＭＰａ）は、表面応力計ＦＳＭ－６０００（折原製作所製）にて表面圧縮応力ＣＳ（ＭＰａ）及び圧縮応力層（表面層及び裏面層）の厚さＤＯＬ（μｍ）を測定し、その測定値と、強化ガラス板の厚さｔ１（μｍ）とから以下の式１を用いて計算した。
       ＣＴ＝（ＣＳ×ＤＯＬ）／（ｔ１－２×ＤＯＬ）　・・・式１
　内部ひずみエネルギーＵＣＴ（Ｊ／ｍ２）は、強化ガラス板のヤング率Ｙ（ＭＰａ）を用いて以下の式２により求めた。
       ＵＣＴ＝｛ＣＴ２×（ｔ１－２×ＤＯＬ)｝／（２×Ｙ）　・・・式２ The internal residual tensile stress CT (MPa) of the tempered glass plate was measured using a surface stress meter FSM-6000 (manufactured by Orihara Seisakusho) and the surface compressive stress CS (MPa) and the thickness DOL (surface layer and back layer) [mu] m) was measured, and the measured values were calculated using equation 1 below color and thickness t 1 ([mu] m) of the tempered glass sheet.
CT = (CS × DOL) / (t 1 −2 × DOL) Equation 1
The internal strain energy U CT (J / m 2 ) was determined by the following formula 2 using the Young's modulus Y (MPa) of the tempered glass plate.
U CT = {CT 2 × (t 1 −2 × DOL)} / (2 × Y) Equation 2
　単位照射面積あたりのレーザ光の照射エネルギーは、強化ガラス板に反射されずに入射される実効的なレーザ出力をＰｅ（Ｗ）、レーザ光の走査速度をｖ（ｍｍ／ｓ）、強化ガラス板１０に照射されるレーザ光のビーム径をφ（ｍｍ）とすると、Ｐｅ／（ｖ×φ）（単位：Ｊ／ｍｍ２）で表すことができる。しかしながら、切断性を判断するためには、これにビーム径φ（ｍｍ）を掛けた単位長さあたりのレーザ光の照射エネルギーＥＬ（Ｊ／ｍｍ）を用いることが好ましい。詳細な理由については後述する。この照射エネルギーＥＬ（Ｊ／ｍｍ）を以下の式４に示す。なお、実効的なレーザ出力Ｐｅ（Ｗ）は、レーザ出力Ｐ（Ｗ）と強化ガラス板での反射率ｒ（％）とを用いて、Ｐｅ＝Ｐ×（１－ｒ／１００）と表すことができる。
       ＥＬ＝Ｐｅ／ｖ　・・・式４
　サンプル１～１１についての照射エネルギーＥＬの臨界値である臨界照射エネルギーＥｃは、照射エネルギーＥＬを約１（Ｊ／ｍｍ）ずつ変化させて切断を繰り返すことにより求めた。その際、レーザ光の走査速度ｖ（ｍｍ／ｓ）は固定したまま、レーザ出力Ｐ（Ｗ）のみを２．５Ｗずつ変化させた。
　また、非強化ガラス板のサンプル１８～２１についての臨界照射エネルギーＥｃは、照射エネルギーＥＬを約４（Ｊ／ｍｍ）ずつ変化させて切断を繰り返すことにより求めた。その際、レーザ光の走査速度ｖ（ｍｍ／ｓ）は固定したまま、レーザ出力Ｐ（Ｗ）のみを１０Ｗずつ変化させた。
　他方、サンプル１２～１７についての臨界照射エネルギーＥｃは、照射エネルギーＥＬを徐々に変化させて切断を繰り返すことにより求めた。その際、レーザ出力Ｐ（Ｗ）は固定したまま、レーザ光の走査速度ｖ（ｍｍ／ｓ）のみを０．２５ｍｍ／ｓずつ変化させた。 The laser beam irradiation energy per unit irradiation area is defined as Pe (W), the effective laser output incident without being reflected on the tempered glass plate, v (mm / s) as the laser beam scanning speed, and the tempered glass plate. 10 is represented by Pe / (v × φ) (unit: J / mm 2 ). However, in order to determine the cutting performance, it is preferable to use the irradiation energy E L (J / mm) of the laser light per unit length obtained by multiplying this by the beam diameter φ (mm). The detailed reason will be described later. This irradiation energy E L (J / mm) is shown in Equation 4 below. The effective laser output Pe (W) is expressed as Pe = P × (1−r / 100) using the laser output P (W) and the reflectance r (%) at the tempered glass plate. Can do.
E L = Pe / v Equation 4
The critical irradiation energy Ec, which is the critical value of the irradiation energy E L for the samples 1 to 11, was obtained by changing the irradiation energy E L by about 1 (J / mm) and repeating the cutting. At that time, only the laser output P (W) was changed by 2.5 W while the scanning speed v (mm / s) of the laser beam was fixed.
The critical irradiation energy Ec for samples 18-21 unreinforced glass plates was determined by repeating the cutting by changing the irradiation energy E L by about 4 (J / mm). At that time, only the laser output P (W) was changed by 10 W while the scanning speed v (mm / s) of the laser beam was fixed.
On the other hand, the critical irradiation energy Ec of the samples 12 to 17 was determined by repeating the cutting is gradually changed the irradiation energy E L. At that time, only the scanning speed v (mm / s) of the laser beam was changed by 0.25 mm / s while the laser output P (W) was fixed.
　図１５は、サンプル１～２１について、レーザ波長λ、内部ひずみエネルギーＵＣＴ、臨界照射エネルギーＥｃ、及び両者を導出するための諸条件が示された表である。表の左列から順に、レーザ波長λ（ｎｍ）、サンプル番号、強化ガラス板のヤング率Ｙ（ＭＰａ）、線膨張係数αＬ（Ｋ－１）、密度ρ（ｇ／ｍｍ３）、比熱ｃ（Ｊ／ｇ／Ｋ）、厚さｔ（ｍｍ）、吸収係数α（ｍｍ－１）、強化ガラス板での反射率ｒ（％）、表面圧縮応力ＣＳ（ＭＰａ）、表面層及び裏面層の厚さＤＯＬ（μｍ）、内部残留引張応力ＣＴ（ＭＰａ）、内部ひずみエネルギーＵＣＴ（Ｊ／ｍ２）、レーザ光の走査速度ｖ（ｍｍ／ｓ）、レーザ光のビーム径φ（ｍｍ）、レーザ出力Ｐ（Ｗ）、実効的なレーザ出力Ｐｅ（Ｗ）、臨界照射エネルギーＥｃ（Ｊ／ｍｍ）、臨界吸収エネルギーＥａ（Ｊ／ｍｍ）、臨界切断指数Ｋｃ（Ｎ／ｍｍ）が示されている。 FIG. 15 is a table showing the laser wavelength λ, the internal strain energy U CT , the critical irradiation energy Ec, and various conditions for deriving both of the samples 1 to 21. In order from the left column of the table, laser wavelength λ (nm), sample number, Young's modulus Y (MPa) of tempered glass plate, linear expansion coefficient α L (K −1 ), density ρ (g / mm 3 ), specific heat c (J / g / K), thickness t (mm), absorption coefficient α (mm −1 ), reflectance r (%) in a tempered glass plate, surface compressive stress CS (MPa), surface layer and back layer Thickness DOL (μm), internal residual tensile stress CT (MPa), internal strain energy U CT (J / m 2 ), laser beam scanning speed v (mm / s), laser beam diameter φ (mm), Laser output P (W), effective laser output Pe (W), critical irradiation energy Ec (J / mm), critical absorption energy Ea (J / mm), critical cutting index Kc (N / mm) are shown. Yes.
　図１５に示すように、サンプル１～１１、１８～２１については、レーザ光の光源にファイバーレーザ（中心波長帯：１０７０ｎｍ）を用い、サンプル１２～１７については、レーザ光の光源に中赤外光パラメトリック発振器を使用したＣｒ：ＺｎＳｅレーザ（中心波長帯：２９５０ｎｍ）を用いた。 As shown in FIG. 15, for samples 1 to 11 and 18 to 21, a fiber laser (center wavelength band: 1070 nm) is used as the laser light source, and for samples 12 to 17, the mid-infrared is used as the laser light source. A Cr: ZnSe laser (central wavelength band: 2950 nm) using an optical parametric oscillator was used.
　また、いずれのサンプルも材質は同じであるため、図１５に示す通り、ヤング率Ｙ＝７４０００ＭＰａ、線膨張係数αＬ＝９．８×１０－６Ｋ－１、密度ρ＝２．４８×１０－３ｇ／ｍｍ３、比熱ｃ＝０．９１８Ｊ／ｇ／Ｋで共通である。
　なお、図１５に示す通り、サンプル１～１１については、ビーム径φ＝０．１ｍｍ、サンプル１２～１７については、ビーム径φ＝０．２ｍｍとした。また、非強化ガラス板のサンプル１８についてはビーム径φ＝０．５ｍｍ、サンプル１９についてはビーム径φ＝０．８ｍｍ、サンプル２０についてはビーム径φ＝１．０ｍｍ、サンプル２１についてはビーム径φ＝２．０ｍｍとした。
　また、全てのサンプルについて、レーザ光照射側から直径１ｍｍφのノズルを用いて、流量１５Ｌ／ｍｉｎの空気を吹き付けた。ここで、強化ガラス板とノズル先端との距離（ギャップ）は３ｍｍとした。 Since all the samples are made of the same material, as shown in FIG. 15, Young's modulus Y = 74000 MPa, linear expansion coefficient α L = 9.8 × 10 −6 K −1 , density ρ = 2.48 × 10 −3 g / mm 3 and specific heat c = 0.918 J / g / K.
As shown in FIG. 15, the beam diameter φ = 0.1 mm for samples 1 to 11, and the beam diameter φ = 0.2 mm for samples 12 to 17. Further, the sample 18 of the non-tempered glass plate has a beam diameter φ = 0.5 mm, the sample 19 has a beam diameter φ = 0.8 mm, the sample 20 has a beam diameter φ = 1.0 mm, and the sample 21 has a beam diameter φ. = 2.0 mm.
For all samples, air having a flow rate of 15 L / min was blown from the laser light irradiation side using a nozzle having a diameter of 1 mmφ. Here, the distance (gap) between the tempered glass plate and the nozzle tip was 3 mm.
　図１６Ａは、図１５の表に示した臨界照射エネルギーＥｃの内部ひずみエネルギーＵＣＴ依存性を示すグラフである。図１６Ａの横軸は内部ひずみエネルギーＵＣＴ（Ｊ／ｍ２）、縦軸は臨界照射エネルギーＥｃ（Ｊ／ｍｍ）である。図１６Ａにおいて、●印はサンプル１～１１、１８～２１（レーザ波長λ＝１０７０ｎｍ）、○印はサンプル１２～１７（レーザ波長λ＝２９５０ｎｍ）を示している。 FIG. 16A is a graph showing the internal strain energy U CT dependence of the critical irradiation energy Ec shown in the table of FIG. The horizontal axis of FIG. 16A is internal strain energy U CT (J / m 2 ), and the vertical axis is critical irradiation energy Ec (J / mm). In FIG. 16A, marks ● indicate samples 1 to 11 and 18 to 21 (laser wavelength λ = 1070 nm), and marks ◯ indicate samples 12 to 17 (laser wavelength λ = 2950 nm).
　図１５、図１６Ａに示すように、レーザ波長λ＝１０７０ｎｍの場合、強化ガラス板の内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２では、臨界照射エネルギーＥｃ＝９～１５Ｊ／ｍｍで安定している（サンプル１～１０）。これに対し、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２では、臨界照射エネルギーＥｃ＝５６Ｊ／ｍｍまで急激に（具体的には数倍程度）上昇する（サンプル１１）。この臨界照射エネルギーＥｃの上昇に伴い、サンプル１１では、切断精度も悪化した。この結果から、強化ガラス板を切断する場合、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とすることにより、小さい照射エネルギーで精度良く切断することができることが分かった。 As shown in FIG. 15 and FIG. 16A, when the laser wavelength λ = 1070 nm, when the internal strain energy U CT ≧ 2.5 J / m 2 of the tempered glass plate, the critical irradiation energy Ec = 9 to 15 J / mm is stable. (Samples 1 to 10). On the other hand, when the internal strain energy U CT <2.5 J / m 2 , it rapidly rises (specifically, several times) to the critical irradiation energy Ec = 56 J / mm (sample 11). As the critical irradiation energy Ec increased, the cutting accuracy of sample 11 also deteriorated. From this result, when cutting strengthened glass sheet, by the internal strain energy U CT ≧ 2.5J / m 2, it was found that it is possible to accurately cut with a small irradiation energy.
　さらに、非強化ガラス板のサンプル１８については切断することができなかった。すなわち、板厚ｔ（＝０．７ｍｍ）以下のビーム径φ＝０．５ｍｍでは、非強化ガラス板のサンプルは切断することができなかった。そして、ビーム径φ＝０．８ｍｍのサンプル１９については臨界照射エネルギーＥｃ＝８３Ｊ／ｍｍ、ビーム径φ＝１．０ｍｍのサンプル２０については臨界照射エネルギーＥｃ＝７６Ｊ／ｍｍ、ビーム径φ＝２．０ｍｍのサンプル２１については臨界照射エネルギーＥｃ＝６５Ｊ／ｍｍであった。すなわち、ビーム径の増大とともに、臨界照射エネルギーＥｃは漸減した。ここで、ビーム径が大きくなる程、レーザ光の中心とクラックの先端位置とが離れるため、切断精度が低下する。そのため、強化ガラス板の切断において、ビーム径φは板厚ｔ以下とすることが好ましく、板厚ｔの１／２以下とすることがさらに好ましい。 Furthermore, the sample 18 of the non-tempered glass plate could not be cut. That is, the sample of the non-tempered glass plate could not be cut at a beam diameter φ of 0.5 mm or less with a plate thickness t (= 0.7 mm). The critical irradiation energy Ec = 83 J / mm for the sample 19 with the beam diameter φ = 0.8 mm, the critical irradiation energy Ec = 76 J / mm for the sample 20 with the beam diameter φ = 1.0 mm, and the beam diameter φ = 2. For the sample 21 of 0 mm, the critical irradiation energy Ec = 65 J / mm. That is, as the beam diameter increased, the critical irradiation energy Ec gradually decreased. Here, as the beam diameter is increased, the center of the laser beam is separated from the tip position of the crack, so that the cutting accuracy is lowered. Therefore, in the cutting of the tempered glass plate, the beam diameter φ is preferably not more than the plate thickness t, and more preferably not more than ½ of the plate thickness t.
　図１６Ａのグラフから、内部ひずみエネルギーＵＣＴ＝２．５Ｊ／ｍ２近傍において、切断モードの変換が生じているものと考えられる。具体的には、強化ガラス板を切断するためのクラック伸展エネルギーとして、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２の場合、内部ひずみエネルギーに加え、レーザ光の照射エネルギーが必要となり（図１２参照）、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２の場合、内部ひずみエネルギーのみになるものと考えられる（図１３参照）。 From the graph of FIG. 16A, it is considered that the conversion of the cutting mode occurs in the vicinity of the internal strain energy U CT = 2.5 J / m 2 . Specifically, when the internal strain energy U CT <2.5 J / m 2 as the crack extension energy for cutting the tempered glass plate, in addition to the internal strain energy, laser beam irradiation energy is required (FIG. 12). In the case of internal strain energy U CT ≧ 2.5 J / m 2 , it is considered that only internal strain energy is obtained (see FIG. 13).
　また、レーザ波長λを１０７０ｎｍから２９５０ｎｍへ変更することにより、強化ガラス板の吸収係数αが０．０１１ｍｍ-１から０．５９ｍｍ-１へ向上する。そのため、図１５、１２に示すように、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２において、臨界照射エネルギーＥｃ＝９～１５Ｊ／ｍｍ程度（サンプル１～１０）から臨界照射エネルギーＥｃ＝０．３～０．５Ｊ／ｍｍ（サンプル１２～１５）まで２桁も低減することができる。 Further, by changing the laser wavelength λ from 1070 nm to 2950 nm, the absorption coefficient α of the tempered glass plate is improved from 0.011 mm −1 to 0.59 mm −1 . Therefore, as shown in FIGS. 15 and 12, when the internal strain energy U CT ≧ 2.5 J / m 2 , the critical irradiation energy Ec = 0.about.0.1 from the critical irradiation energy Ec = about 9 to 15 J / mm (samples 1 to 10). It can be reduced by two orders of magnitude from 3 to 0.5 J / mm (samples 12 to 15).
　このように、レーザ波長を３０００ｎｍ近傍とすることにより、透明度を低下させずに吸収係数αを高めることができ、照射エネルギーを低減することができる。そのため、加熱効率が向上する。その上、強化ガラス板の組成によりレーザ光の照射条件を大幅に変更する必要がない。
　さらに、上述の通り、切断する強化ガラス板より大きなテーブルに強化ガラスを載せ、より安定した状態で切断することができる。また、透過光が劇的に減少するため、その処理も不要となる。さらに、強化ガラス板の端面における反射光も劇的に減少するため、悪影響を及ぼし難い。 Thus, by setting the laser wavelength to around 3000 nm, the absorption coefficient α can be increased without lowering the transparency, and the irradiation energy can be reduced. Therefore, the heating efficiency is improved. In addition, it is not necessary to significantly change the laser light irradiation conditions depending on the composition of the tempered glass plate.
Furthermore, as above-mentioned, tempered glass can be mounted on a table larger than the tempered glass board to cut | disconnect, and it can cut | disconnect in a more stable state. Further, since the transmitted light is dramatically reduced, the processing is not necessary. Furthermore, since the reflected light at the end face of the tempered glass plate also decreases dramatically, it is difficult to exert an adverse effect.
　また、レーザ波長λが２９５０ｎｍの場合も、１０７０ｎｍの場合と同様に、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２では、臨界照射エネルギーＥｃ＝０．９～１．２Ｊ／ｍｍ程度あるいはそれ以上まで急激に上昇する（サンプル１６、１７）。この臨界照射エネルギーＥｃの上昇に伴い、サンプル１６、１７では、切断精度も悪化した。この結果から、レーザ波長λ＝２９５０ｎｍで強化ガラス板を切断する場合も、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とすることにより、小さい照射エネルギーで精度良く切断することができることが分かった。 When the laser wavelength λ is 2950 nm, as in the case of 1070 nm, the critical irradiation energy Ec is about 0.9 to 1.2 J / mm or more when the internal strain energy U CT <2.5 J / m 2. (Samples 16 and 17). With the increase in the critical irradiation energy Ec, the cutting accuracy of the samples 16 and 17 also deteriorated. From this result, it was found that even when a tempered glass plate is cut at a laser wavelength λ = 2950 nm, the internal strain energy U CT ≧ 2.5 J / m 2 can be cut accurately with a small irradiation energy. .
　ここで、臨界照射エネルギーＥｃのうち、切断に使用されるエネルギーは強化ガラス板に吸収されるエネルギー（以下、臨界吸収エネルギーという）Ｅａである。臨界吸収エネルギーＥａ（Ｊ／ｍｍ）は、臨界照射エネルギーＥｃ（Ｊ／ｍｍ）、吸収係数α（ｍｍ－１）、厚さｔ２（ｍｍ）を用いて、ランベルト・ベールの法則から次式で表すことができる。
       Ｅａ＝Ｅｃ×ｅｘｐ（－α×ｔ２）　・・・式５
　図１５に示すように、臨界吸収エネルギーＥａ（Ｊ／ｍｍ）の値は、レーザ波長λが２９５０ｎｍの場合と１０７０ｎｍの場合とを比較しても、ほとんど差が無い。 Here, of the critical irradiation energy Ec, the energy used for cutting is energy (hereinafter referred to as critical absorption energy) Ea absorbed by the tempered glass plate. The critical absorption energy Ea (J / mm) is calculated from the Lambert-Beer law using the following equation using the critical irradiation energy Ec (J / mm), the absorption coefficient α (mm −1 ), and the thickness t 2 (mm): Can be represented.
Ea = Ec × exp (−α × t 2 ) Equation 5
As shown in FIG. 15, there is almost no difference in the value of the critical absorption energy Ea (J / mm) even when the laser wavelength λ is 2950 nm and 1070 nm.
　強化ガラス板の厚さや材質による影響を排除し、より一般化するため、臨界吸収エネルギーＥａでの内部加熱（温度変化ΔＴ）によって発生する熱応力（臨界圧縮応力）σｃについて考察する。この臨界圧縮応力σｃは、切断に必要な最小の圧縮応力である。ここで、臨界圧縮応力σｃは、内部残留引張応力ＣＴを基準とした場合に圧縮応力となるので「臨界圧縮応力」と表現している。しかし、図１２、１３に示すように、強化ガラス板の板厚中心部に発生する応力で考えた場合は、内部残留引張応力ＣＴと臨界圧縮応力σｃとの合力で表されるので、引張応力となる場合もある。 In order to eliminate the influence of the thickness and material of the tempered glass plate and to generalize it, the thermal stress (critical compressive stress) σc generated by internal heating (temperature change ΔT) at the critical absorption energy Ea will be considered. This critical compressive stress σc is the minimum compressive stress necessary for cutting. Here, the critical compressive stress σc is expressed as “critical compressive stress” because it becomes a compressive stress when the internal residual tensile stress CT is used as a reference. However, as shown in FIGS. 12 and 13, when considering the stress generated at the center of the thickness of the tempered glass plate, it is expressed by the resultant force of the internal residual tensile stress CT and the critical compressive stress σc. It may become.
　臨界圧縮応力σｃは、図１２、１３に示すように、ガウス分布様のプロファイルを有している。この臨界圧縮応力σｃの積分値（図１２、１３における斜線部の面積）が、切断可否を決定する。内部ひずみエネルギーＵＣＴが同じであれば、臨界圧縮応力σｃの積分値は、強化ガラス板の厚さｔ、材質によらず一定であると考えられる。臨界圧縮応力σｃのプロファイルの幅は、ビーム径φに比例するから、臨界圧縮応力σｃの積分値も、σｃ×φに比例すると考えてよい。 The critical compressive stress σc has a Gaussian distribution-like profile as shown in FIGS. The integral value of this critical compressive stress σc (the area of the hatched portion in FIGS. 12 and 13) determines whether cutting is possible. If the internal strain energy U CT is the same, the integral value of the critical compressive stress σc is considered to be constant regardless of the thickness t and the material of the tempered glass sheet. Since the width of the profile of the critical compressive stress σc is proportional to the beam diameter φ, it can be considered that the integrated value of the critical compressive stress σc is also proportional to σc × φ.
　ここで、単純化のために、内部加熱によっても強化ガラス板の板厚ｔは変化せず、表面層１３と裏面層１５との間で拘束されることによりこの臨界圧縮応力σｃが生じるものとする。すなわち、両端拘束モデルを考える。
　臨界圧縮応力σｃ（ＭＰａ）は、ヤング率Ｙ（ＭＰａ）、線膨張係数αＬ（Ｋ－１）、温度変化ΔＴ（Ｋ）を用いて、次式６で表すことができる。
       σｃ＝Ｙ×αＬ×ΔＴ　・・・式６ Here, for simplification, the plate thickness t of the tempered glass plate does not change even by internal heating, and this critical compressive stress σc is generated by being constrained between the front surface layer 13 and the back surface layer 15. To do. That is, consider a both-end constraint model.
The critical compressive stress σc (MPa) can be expressed by the following formula 6 using the Young's modulus Y (MPa), the linear expansion coefficient α L (K −1 ), and the temperature change ΔT (K).
σc = Y × α L × ΔT Equation 6
　また、臨界吸収エネルギーＥａが供給されることによる強化ガラス板の温度変化ΔＴは、ΔＴ＝（臨界吸収エネルギー）／（レーザ照射部の強化ガラス板の熱容量）により求めることができる。
　ここで、レーザ照射面積Ｓ１（ｍｍ２）とすれば、（臨界吸収エネルギー）は、臨界吸収エネルギーＥａ（Ｊ／ｍｍ）をφ（ｍｍ）で割った単位面積当たりの臨界吸収エネルギーＥａ／φ（Ｊ／ｍｍ２）を用いて、Ｅａ×Ｓ１／φ（Ｊ）で表すことができる。
　また、強化ガラス板における加熱領域の面積Ｓ２（ｍｍ２）とすると、（レーザ照射部の強化ガラス板の熱容量）は、強化ガラス板の厚さｔ２（ｍｍ）、密度ρ（ｇ／ｍｍ３）、比熱ｃ（Ｊ／ｇ／Ｋ）を用いて、Ｓ２×ｔ２×ρ×ｃ（Ｊ／Ｋ）で表すことができる。 Further, the temperature change ΔT of the tempered glass plate due to the supply of the critical absorption energy Ea can be obtained by ΔT = (critical absorption energy) / (heat capacity of the tempered glass plate of the laser irradiation portion).
Here, assuming that the laser irradiation area S 1 (mm 2 ), (critical absorption energy) is critical absorption energy Ea / φ per unit area obtained by dividing critical absorption energy Ea (J / mm) by φ (mm). Using (J / mm 2 ), it can be expressed as Ea × S 1 / φ (J).
Further, assuming that the area S 2 (mm 2 ) of the heating region in the tempered glass plate, (the heat capacity of the tempered glass plate of the laser irradiation part) is the thickness t 2 (mm) of the tempered glass plate, and the density ρ (g / mm). 3 ), and can be expressed as S 2 × t 2 × ρ × c (J / K) using specific heat c (J / g / K).
　従って、温度変化ΔＴ（Ｋ）は次式７で表すことができる。
       ΔＴ＝Ｅａ×Ｓ１／（Ｓ２×ｔ２×ρ×ｃ）／φ
       　　＝（Ｓ１／Ｓ２）×Ｅａ／（ｔ２×ρ×ｃ）／φ　・・・式７
　式６に式７を代入することにより、臨界圧縮応力σｃ（ＭＰａ）は次式８で表すことができる。
       σｃ＝（Ｓ１／Ｓ２）×Ｙ×αＬ×Ｅａ／（ｔ２×ρ×ｃ）／φ　・・・式８
　ここで、単純化のために、Ｓ１／Ｓ２＝一定と考えれば、求めるべき臨界圧縮応力σｃの積分値に比例するσｃ×φは次式９で表すことができる。
       σｃ×φ∝Ｅａ×（Ｙ×αＬ）／（ｔ２×ρ×ｃ）＝Ｋｃ　・・・式９
　式９のＫｃを臨界切断指数と名付ける。切断可能な臨界値を示すこの臨界切断指数Ｋｃの値が小さくなる程、切断が容易になり、臨界切断指数Ｋｃの値が大きくなる程、切断が困難になる。このように、切断性は、式４で示された単位長さあたりのレーザ光の照射エネルギーＥＬ（Ｊ／ｍｍ）により判断できる。 Therefore, the temperature change ΔT (K) can be expressed by the following equation 7.
ΔT = Ea × S 1 / (S 2 × t 2 × ρ × c) / φ
= (S 1 / S 2 ) × Ea / (t 2 × ρ × c) / φ Equation 7
By substituting Equation 7 into Equation 6, the critical compressive stress σc (MPa) can be expressed by the following Equation 8.
σc = (S 1 / S 2 ) × Y × α L × Ea / (t 2 × ρ × c) / φ Equation 8
Here, for simplification, assuming that S 1 / S 2 = constant, σc × φ proportional to the integral value of the critical compressive stress σc to be obtained can be expressed by the following equation (9).
σc × φ∝Ea × (Y × α L ) / (t 2 × ρ × c) = Kc Equation 9
Kc in Equation 9 is named the critical cutting index. Cutting becomes easier as the value of the critical cutting index Kc indicating the critical value that can be cut becomes smaller, and cutting becomes more difficult as the value of the critical cutting index Kc increases. As described above, the cutting property can be determined by the irradiation energy E L (J / mm) of the laser beam per unit length expressed by the equation 4.
　臨界切断指数Ｋｃを構成するヤング率Ｙ、線膨張係数αＬ、密度ρ、比熱ｃは、いずれも温度依存性を有するが、あくまで指標として室温の値を用いている。
　図１５の最右列に臨界切断指数Ｋｃ（Ｎ／ｍｍ）を示した。 The Young's modulus Y, linear expansion coefficient α L , density ρ, and specific heat c constituting the critical cutting index Kc all have temperature dependence, but room temperature values are used as indices only.
The critical cutting index Kc (N / mm) is shown in the rightmost column of FIG.
　図１６Ｂは、図１５の表に示した臨界切断指数Ｋｃの内部ひずみエネルギーＵＣＴ依存性を示すグラフである。図１６Ｂの横軸は内部ひずみエネルギーＵＣＴ（Ｊ／ｍ２）、縦軸は臨界切断指数Ｋｃ（Ｎ／ｍｍ）である。図１６Ｂにおいて、●印はサンプル１～１１、１８～２１（レーザ波長λ＝１０７０ｎｍ）、○印はサンプル１２～１７（レーザ波長λ＝２９５０ｎｍ）を示している。 FIG. 16B is a graph showing the internal strain energy U CT dependence of the critical cutting index Kc shown in the table of FIG. The horizontal axis in FIG. 16B is the internal strain energy U CT (J / m 2 ), and the vertical axis is the critical cutting index Kc (N / mm). In FIG. 16B, the black circles indicate samples 1 to 11 and 18 to 21 (laser wavelength λ = 1070 nm), and the ◯ marks indicate samples 12 to 17 (laser wavelength λ = 2950 nm).
　図１５、図１６Ｂに示すように、レーザ波長λによらず、強化ガラス板の内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２では、臨界切断指数Ｋｃ＝５０Ｎ／ｍｍ近傍で安定している（サンプル１～１０、１２～１５）。これに対し、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２では、臨界切断指数Ｋｃ＝１５０Ｎ／ｍｍ（サンプル１６）あるいは２００Ｎ／ｍｍを超えるようになる（サンプル１１、１７）。さらに、非強化ガラス板では２５０Ｎ／ｍｍを超えるようになる（サンプル１８～２１）。ここで、ビーム径が小さくなる程臨界切断指数Ｋｃが大きくなり、ビーム径が０．５ｍｍ以下では切断できなくなる（サンプル１８）。 As shown in FIGS. 15 and 16B, regardless of the laser wavelength λ, the internal strain energy U CT ≧ 2.5 J / m 2 of the tempered glass plate is stable near the critical cutting index Kc = 50 N / mm ( Samples 1-10, 12-15). On the other hand, when the internal strain energy U CT <2.5 J / m 2 , the critical cutting index Kc = 150 N / mm (sample 16) or exceeds 200 N / mm (samples 11 and 17). Further, the non-tempered glass plate exceeds 250 N / mm (samples 18 to 21). Here, as the beam diameter becomes smaller, the critical cutting index Kc becomes larger, and when the beam diameter is 0.5 mm or less, cutting becomes impossible (sample 18).
　この臨界切断指数Ｋｃの上昇に伴い、切断精度も悪化した。この結果から、強化ガラス板を切断する場合、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とすることにより、小さい照射エネルギーで精度良く切断することができることが分かった。また、ビーム径が大きくなる程、レーザ光の中心とクラックの先端位置とが離れるため、切断精度が低下する。そのため、ビーム径φは板厚ｔ２（ｍｍ）以下とすることが好ましく、板厚ｔ２（ｍｍ）の１／２以下とすることがさらに好ましい。 As the critical cutting index Kc increased, the cutting accuracy also deteriorated. From this result, when cutting strengthened glass sheet, by the internal strain energy U CT ≧ 2.5J / m 2, it was found that it is possible to accurately cut with a small irradiation energy. Further, as the beam diameter increases, the center of the laser beam and the tip position of the crack are separated from each other, so that the cutting accuracy decreases. Therefore, the beam diameter φ preferably set to less thickness t 2 (mm), and even more preferably to a half or less of the plate thickness t 2 (mm).
　単位長さあたりの照射エネルギーＥＬ（Ｊ／ｍｍ）での切断指数Ｋは、式５におけるＥｃをＥＬに置き換えた上で、式９におけるＥａに代入することにより、次式１０で表すことができる。ここで、切断指数Ｋが臨界切断指数Ｋｃ以上であれば切断可能となる。
       Ｋ＝ＥＬ×ｅｘｐ（－α×ｔ２）×（Ｙ×αＬ）／（ｔ２×ρ×ｃ）　・・・式１０
　さらに、式１０に式４を代入することにより、以下の式１１が得られる。
       Ｋ＝Ｐｅ／ｖ×ｅｘｐ（－α×ｔ２）×（Ｙ×αＬ）／（ｔ２×ρ×ｃ）・・式１１ Cutting index K of the irradiation energy E L (J / mm) per unit length, on replacing the Ec in the equation 5 to E L, by substituting the Ea in equation 9, it is represented by the following formula 10 Can do. Here, if the cutting index K is greater than or equal to the critical cutting index Kc, cutting is possible.
K = E L × exp (−α × t 2 ) × (Y × α L ) / (t 2 × ρ × c) Equation 10
Further, by substituting Expression 4 into Expression 10, the following Expression 11 is obtained.
K = Pe / v × exp (−α × t 2 ) × (Y × α L ) / (t 2 × ρ × c).
　図１６Ｂから、内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２であれば、臨界切断指数Ｋｃが５０Ｎ／ｍｍ程度であるため、切断指数Ｋ≦１５０Ｎ／ｍｍを満たす照射エネルギーＥＬで十分に切断できる。一方、図１６Ｂから、内部ひずみエネルギーＵＣＴ＜２．５Ｊ／ｍ２であれば、臨界切断指数Ｋｃが１５０Ｎ／ｍｍ以上となるため、切断指数Ｋ≦１５０Ｎ／ｍｍを満たす照射エネルギーＥＬでは、切断が不可能あるいは困難になる。内部ひずみエネルギーＵＣＴ≧２．５Ｊ／ｍ２とした上で、切断指数Ｋ≦１５０Ｎ／ｍｍを満たす照射エネルギーＥＬとすることにより、小さい照射エネルギーで精度良く切断することができる。切断指数Ｋ≦１００Ｎ／ｍｍを満たす照射エネルギーＥＬとすることにより、さらに小さい照射エネルギーでさらに精度良く切断することができる。 From FIG. 16B, if the internal strain energy U CT ≧ 2.5 J / m 2 , the critical cutting index Kc is about 50 N / mm, so that sufficient cutting can be performed with the irradiation energy E L satisfying the cutting index K ≦ 150 N / mm. it can. On the other hand, from FIG. 16B, if the internal strain energy U CT <2.5 J / m 2 , the critical cutting index Kc is 150 N / mm or more. Therefore, in the irradiation energy E L that satisfies the cutting index K ≦ 150 N / mm, Cutting becomes impossible or difficult. On which the internal strain energy U CT ≧ 2.5J / m 2, by the irradiation energy E L satisfying cutting index K ≦ 150N / mm, it is possible to accurately cut with a small irradiation energy. By the irradiation energy E L satisfying cutting index K ≦ 100N / mm, it is possible to more accurately cut with a smaller irradiation energy.
　以下、本発明の具体的な実施例について説明する。実施例１では、単位時間当たりの単位照射エネルギーの変化量と設計寸法からのずれ量（寸法誤差）との関係を説明する。 Hereinafter, specific examples of the present invention will be described. In Example 1, the relationship between the amount of change in unit irradiation energy per unit time and the amount of deviation (dimension error) from the design dimension will be described.
＜実施例１＞
　実施例１では、板厚が１．１ｍｍ、表面圧縮応力ＣＳが７５６ＭＰａ、表面層及び裏面層それぞれの厚さＤＯＬが３０．５μｍ、残留引張応力ＣＴが２２ＭＰａの強化ガラス板（サンプルＡ）と、板厚が１．１ｍｍ、表面圧縮応力ＣＳが７１６ＭＰａ、表面層及び裏面層それぞれの厚さＤＯＬが６８．８μｍ、残留引張応力ＣＴが５１ＭＰａの強化ガラス板（サンプルＢ）と、を用いた。 <Example 1>
In Example 1, a tempered glass plate (sample A) having a plate thickness of 1.1 mm, a surface compressive stress CS of 756 MPa, a thickness DOL of each of the surface layer and the back layer of 30.5 μm, and a residual tensile stress CT of 22 MPa, A tempered glass plate (sample B) having a plate thickness of 1.1 mm, a surface compressive stress CS of 716 MPa, a thickness DOL of each of the front surface layer and the back surface layer of 68.8 μm, and a residual tensile stress CT of 51 MPa was used.
　図１７は、切り出された強化ガラスパネルの形状を示している。図１７に示すように、長さＬ＝５０ｍｍ、幅Ｗ＝３５ｍｍ、コーナー部の曲率半径Ｒ＝５ｍｍである。
　また、図１７に示す通り、コーナー部と直線部との境界付近の幅Ｗ１、Ｗ３、長手方向中央部の幅Ｗ２、コーナー部と直線部との境界付近の長さＬ１、Ｌ３、幅方向中央部の長さＬ２の合計６つの寸法を、ノギスを用いて測定した。そして、各寸法について寸法誤差δを計算した。 FIG. 17 shows the shape of the cut-out tempered glass panel. As shown in FIG. 17, the length L is 50 mm, the width W is 35 mm, and the curvature radius R of the corner portion is 5 mm.
In addition, as shown in FIG. 17, widths W1 and W3 in the vicinity of the boundary between the corner portion and the straight portion, width W2 in the central portion in the longitudinal direction, lengths L1 and L3 in the vicinity of the boundary between the corner portion and the straight portion, and the center in the width direction A total of six dimensions of the part length L2 were measured using calipers. Then, a dimensional error δ was calculated for each dimension.
　強化ガラス板の残留引張応力ＣＴは、表面応力計ＦＳＭ－６０００（折原製作所製）にて表面圧縮応力ＣＳ及び圧縮応力層（表面層及び裏面層）の厚さＤＯＬを測定し、その測定値と、強化ガラス板の厚さｔとから式１を用いて計算した。 The residual tensile stress CT of the tempered glass plate is measured by measuring the surface compressive stress CS and the thickness DOL of the compressive stress layer (surface layer and back layer) with a surface stress meter FSM-6000 (manufactured by Orihara Seisakusho). From the thickness t of the tempered glass plate, calculation was performed using Equation 1.
　強化ガラス板は、図６を参照して説明した切断方法により切断した。強化ガラス板の端部の切断開始位置には、初期クラックを予め形成し、強化ガラス板の表面には、スクライブ線を形成しなかった。レーザ光の光源は、ファイバーレーザ（中心波長帯：１０７０ｎｍ）とした。 The tempered glass plate was cut by the cutting method described with reference to FIG. An initial crack was formed in advance at the cutting start position at the end of the tempered glass plate, and no scribe line was formed on the surface of the tempered glass plate. The light source of the laser light was a fiber laser (central wavelength band: 1070 nm).
　図１８は、強化ガラス板の切断条件を示す表である。図１８の表には、各サンプルＮｏ．Ａ１～Ａ４（サンプルＡ）、Ｂ１～Ｂ４（サンプルＢ）を切断する際の条件が示されている。具体的には、表の左列から順に、サンプル番号、レーザ出力Ｐ（Ｗ）、ビーム径φ（ｍｍ）、直線部及びコーナー部でのレーザ光の走査速度ｖ（ｍｍ／ｓ）、直線部とコーナー部とでの走査速度変化量Δｖ（ｍｍ／ｓ）、コーナー部出口での走査速度の加速度ａ（ｍｍ／ｓ２）、コーナー部出口での走査速度の切換時間Ｔ（ｓ）、直線部及びコーナー部における単位照射エネルギーＥ（Ｊ／ｍｍ２）、直線部とコーナー部とでの単位照射エネルギー変化量ΔＥ（Ｊ／ｍｍ２）、単位時間当たりの単位照射エネルギー変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）が示されている。 FIG. 18 is a table showing cutting conditions for the tempered glass sheet. In the table of FIG. The conditions for cutting A1 to A4 (sample A) and B1 to B4 (sample B) are shown. Specifically, in order from the left column of the table, the sample number, laser output P (W), beam diameter φ (mm), laser beam scanning speed v (mm / s) at the linear and corner portions, linear portion Change rate Δv (mm / s) at the corner portion, acceleration a (mm / s 2 ) at the corner portion exit, scanning speed switching time T (s) at the corner portion exit, straight line Unit irradiation energy E (J / mm 2 ) at the corner and corner, unit irradiation energy change ΔE (J / mm 2 ) between the straight part and the corner, unit irradiation energy change ΔE / T (per unit time) J / mm 2 / s).
　図１８の表に示された数値について左列から順に説明する。
　レーザ出力Ｐは、サンプルＡ１～Ａ４については、いずれも１００Ｗとし、サンプルＢ１～Ｂ４については、いずれも８０Ｗとした。
　ビーム径φは全てのサンプルについて、０．１ｍｍとした。
　直線部及びコーナー部でのレーザ光の走査速度ｖ（ｍｍ／ｓ）は、全てのサンプルについて、それぞれ５ｍｍ／ｓ及び１ｍｍ／ｓとした。
　従って、直線部とコーナー部とでの走査速度変化量Δｖ（ｍｍ／ｓ）は、全てのサンプルについて、４ｍｍ／ｓとなる。 The numerical values shown in the table of FIG. 18 will be described in order from the left column.
The laser output P was 100 W for all of samples A1 to A4, and 80 W for all of samples B1 to B4.
The beam diameter φ was 0.1 mm for all samples.
The scanning speed v (mm / s) of the laser beam at the straight line portion and the corner portion was 5 mm / s and 1 mm / s for all the samples, respectively.
Therefore, the scanning speed change amount Δv (mm / s) between the straight line portion and the corner portion is 4 mm / s for all the samples.
　実施例１では、単位時間当たりの単位照射エネルギー変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）を変化させるために、コーナー部出口での走査速度の加速度ａ（ｍｍ／ｓ２）を変化させた。図１８に示すように、サンプルＡ１～Ａ４については、加速度ａ（ｍｍ／ｓ２）をそれぞれ１、３、５、２０ｍｍ／ｓ２とし、サンプルＢ１～Ｂ４については、加速度ａ（ｍｍ／ｓ２）をそれぞれ１、３、５、１０ｍｍ／ｓ２とした。
　コーナー部出口での走査速度の切換時間Ｔ（ｓ）は、走査速度変化量Δｖ（ｍｍ／ｓ）を加速度ａ（ｍｍ／ｓ２）により割ることで求めた。 In Example 1, in order to change the unit irradiation energy change amount ΔE / T (J / mm 2 / s) per unit time, the acceleration a (mm / s 2 ) of the scanning speed at the corner exit is changed. It was. As shown in FIG. 18, the samples A1 ~ A4 is to acceleration a the (mm / s 2), respectively 1,3,5,20mm / s 2, for the samples B1 ~ B4 are acceleration a (mm / s 2 ) Was set to 1, 3, 5, 10 mm / s 2 , respectively.
The scanning speed switching time T (s) at the corner exit was obtained by dividing the scanning speed change Δv (mm / s) by the acceleration a (mm / s 2 ).
　単位照射エネルギーＥ（Ｊ／ｍｍ２）は、上記の式３にレーザ出力Ｐ（Ｗ）、レーザ光の走査速度ｖ（ｍｍ／ｓ）、及びビーム径φ（ｍｍ）を代入することで求めた。その結果、直線部における単位照射エネルギーＥ（Ｊ／ｍｍ２）は、サンプルＡ１～Ａ４については、いずれも２００Ｊ／ｍｍ２、サンプルＢ１～Ｂ４については、いずれも１６０Ｊ／ｍｍ２となった。一方、コーナー部における単位照射エネルギーＥ（Ｊ／ｍｍ２）は、サンプルＡ１～Ａ４については、いずれも１０００Ｊ／ｍｍ２、サンプルＢ１～Ｂ４については、いずれも８００Ｊ／ｍｍ２となった。
　従って、直線部とコーナー部とでの単位照射エネルギー変化量ΔＥ（Ｊ／ｍｍ２）は、サンプルＡ１～Ａ４については、いずれも８００Ｊ／ｍｍ２、サンプルＢ１～Ｂ４については、いずれも６４０Ｊ／ｍｍ２となった。 The unit irradiation energy E (J / mm 2 ) was obtained by substituting the laser output P (W), the laser beam scanning speed v (mm / s), and the beam diameter φ (mm) into the above Equation 3. . As a result, the unit irradiation energy E in the linear portion (J / mm 2), for example A1 ~ A4 are all 200 J / mm 2, for the samples B1 ~ B4 are all became 160 J / mm 2. On the other hand, the unit irradiation energy E (J / mm 2) is at the corner portion, the samples A1 ~ A4 are all 1000 J / mm 2, for the samples B1 ~ B4 are all became 800 J / mm 2.
Thus, the linear unit and the unit irradiation energy amount of change in a corner portion ΔE (J / mm 2), for example A1 ~ A4 are all 800 J / mm 2, for the samples B1 ~ B4 are all 640J / mm 2
　単位時間当たりの単位照射エネルギー変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）は、単位照射エネルギー変化量ΔＥ（Ｊ／ｍｍ２）を切換時間Ｔ（ｓ）により割ることで求めた。図１８に示すように、サンプルＡ１～Ａ４については、それぞれ２００、６００、１０００、４０００Ｊ／ｍｍ２／ｓとなり、サンプルＢ１～Ｂ４については、それぞれ１６０、４８０、８００、１６００Ｊ／ｍｍ２／ｓとなった。 The unit irradiation energy change amount ΔE / T (J / mm 2 / s) per unit time was obtained by dividing the unit irradiation energy change amount ΔE (J / mm 2 ) by the switching time T (s). As shown in FIG. 18, the samples A1 to A4 are 200, 600, 1000, and 4000 J / mm 2 / s, respectively, and the samples B1 to B4 are 160, 480, 800, and 1600 J / mm 2 / s, respectively. became.
　なお、図１８には記載されていないが、全てのサンプルについて、コーナー部入口での走査速度の加速度は－１００ｍｍ／ｓ２（つまり、減速度１００ｍｍ／ｓ２）とした。
　また、全てのサンプルについて、レーザ光照射側から直径１ｍｍφのノズルを用いて、流量１５Ｌ／ｍｉｎの空気を吹き付けた。ここで、強化ガラス板とノズル先端との距離（ギャップ）は２ｍｍとした。 Although not described in FIG. 18, for all samples, the acceleration of the scanning velocity at the corner portion inlet was -100 mm / s 2 (i.e., deceleration 100mm / s 2).
For all samples, air having a flow rate of 15 L / min was blown from the laser light irradiation side using a nozzle having a diameter of 1 mmφ. Here, the distance (gap) between the tempered glass plate and the nozzle tip was 2 mm.
　図１９は、実施例１に係る強化ガラス板の切断方法に用いた冷却ノズルの断面図である。図１９に示す冷却ノズル２８により、強化ガラス板１０の表面１２に気体を吹き付ける。図１９に示すように、冷却ノズル２８は、内部を気体（空気や窒素など）が矢印方向へ流れるように、テーパー状の空洞が形成されている。ここで、冷却ノズル２８の軸はレーザ光の光軸と一致しており、レンズ２５で集光されたレーザ光２０は、冷却ノズル２８の内部を通過し、冷却ノズル２８の先端に設けられた直径φｎの開口部から出射する。また、レーザ光の照射領域の移動と同期して（つまり、レーザ光と同じ走査速度で）移動することができる。このような構成により、レーザ照射部（レーザ光２０の照射領域２２）が気体により冷却される。この冷却により、図３に示したクラック３０の先端位置と、レーザ光２０の照射領域２２との間の距離が短くなり、切断精度が向上する。 FIG. 19 is a cross-sectional view of the cooling nozzle used in the method for cutting a strengthened glass sheet according to Example 1. A gas is blown onto the surface 12 of the tempered glass plate 10 by the cooling nozzle 28 shown in FIG. As shown in FIG. 19, the cooling nozzle 28 has a tapered cavity so that gas (air, nitrogen, etc.) flows in the direction of the arrow. Here, the axis of the cooling nozzle 28 coincides with the optical axis of the laser beam, and the laser beam 20 collected by the lens 25 passes through the inside of the cooling nozzle 28 and is provided at the tip of the cooling nozzle 28. The light is emitted from an opening having a diameter φn. Further, it can move in synchronization with the movement of the laser light irradiation area (that is, at the same scanning speed as the laser light). With such a configuration, the laser irradiation part (irradiation region 22 of the laser light 20) is cooled by the gas. By this cooling, the distance between the tip position of the crack 30 shown in FIG. 3 and the irradiation region 22 of the laser beam 20 is shortened, and the cutting accuracy is improved.
　冷却ノズル２８の開口部の直径φｎ、及び冷却ノズル２８の先端と強化ガラス板１０の表面１２との距離Ｇ１は任意に決定することができる。ここで、冷却ノズル２８の開口部の直径φｎが小さい程、強化ガラス板１０に吹き付けられる気体の流速が速くなり、強化ガラス板１０の表面１２における冷却能力が向上する。また、冷却ノズル２８の先端と強化ガラス板１０の表面との距離Ｇ１が小さい程、強化ガラス板１０の表面１２における冷却能力が向上する。 The diameter φn of the opening of the cooling nozzle 28 and the distance G1 between the tip of the cooling nozzle 28 and the surface 12 of the tempered glass plate 10 can be arbitrarily determined. Here, as the diameter φn of the opening of the cooling nozzle 28 is smaller, the flow rate of the gas blown to the tempered glass plate 10 becomes faster, and the cooling capacity on the surface 12 of the tempered glass plate 10 is improved. Moreover, the cooling capability in the surface 12 of the tempered glass board 10 improves, so that the distance G1 of the front-end | tip of the cooling nozzle 28 and the surface of the tempered glass board 10 is small.
　さらに、図示しないが、コーナー部Ｃ１～Ｃ４の４箇所については、それぞれ強化ガラス板１０の裏面１４側からも固定された直径１ｍｍφのノズルを用いて、流量１５Ｌ／ｍｉｎの空気を吹き付けた。 Further, although not shown, air at a flow rate of 15 L / min was sprayed at four corners C1 to C4 using nozzles with a diameter of 1 mmφ fixed from the back surface 14 side of the tempered glass plate 10 respectively.
　図２０は、強化ガラス板の切断結果を示す表である。
　図２０の表には、各サンプルの単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）と、各サンプルから切り出された強化ガラスパネルの寸法誤差が示されている。具体的には、表の左列から順に、サンプル番号、単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）、幅（Ｗ１～Ｗ３）の寸法誤差の最小値δＷｍｉｎ（ｍｍ）、幅（Ｗ１～Ｗ３）の寸法誤差の最大値δＷｍａｘ（ｍｍ）、長さ（Ｌ１～Ｌ３）の寸法誤差の最小値δＬｍｉｎ（ｍｍ）、長さ（Ｌ１～Ｌ３）の寸法誤差の最大値δＬｍａｘ（ｍｍ）、寸法誤差幅Δδ（ｍｍ）、最大寸法誤差δｍａｘ（ｍｍ）、幅（Ｗ１～Ｗ３）の寸法誤差及び長さ（Ｌ１～Ｌ３）の寸法誤差の平均値δａｖｇ（ｍｍ）が示されている。 FIG. 20 is a table showing the cutting results of the tempered glass sheet.
The table of FIG. 20 shows the change amount ΔE / T (J / mm 2 / s) of unit irradiation energy per unit time of each sample and the dimensional error of the tempered glass panel cut out from each sample. . Specifically, in order from the left column of the table, the sample number, the change amount ΔE / T (J / mm 2 / s) of the unit irradiation energy, the minimum value δWmin (mm) of the dimensional error of the width (W1 to W3), Dimension error maximum value δWmax (mm) of width (W1 to W3), dimensional error minimum value δLmin (mm) of length (L1 to L3), dimensional error maximum value δLmax (length (L1 to L3)) mm), dimensional error width Δδ (mm), maximum dimensional error δmax (mm), dimensional error of width (W1 to W3) and average value δavg (mm) of dimensional error of length (L1 to L3) are shown. Yes.
　ここで、寸法誤差幅Δδは、幅の寸法誤差δＷと長さの寸法誤差δＬのうち最大のものと最小のものとの差で定義される。具体的には、図２０の幅の寸法誤差の最大値δＷｍａｘ（ｍｍ）と長さの寸法誤差の最大値δＬｍａｘ（ｍｍ）の大きい方と、幅の寸法誤差の最小値δＷｍｉｎ（ｍｍ）と長さの寸法誤差の最小値δＬｍｉｎ（ｍｍ）の小さい方との差である。例えば、サンプルＡ２の場合、寸法誤差幅Δδは、長さの寸法誤差の最大値δＬｍａｘ＝０．１５ｍｍと幅の寸法誤差の最小値δＷｍｉｎ＝０．０１ｍｍとの差０．１４ｍｍとなる。 Here, the dimension error width Δδ is defined by the difference between the maximum and minimum of the width dimension error δW and the length dimension error δL. Specifically, the larger one of the maximum width error δWmax (mm) and the maximum length error δLmax (mm) in FIG. 20, and the minimum width error δWmin (mm) and length. This is the difference from the smaller dimensional error minimum value δLmin (mm). For example, in the case of sample A2, the dimensional error width Δδ is 0.14 mm, which is the difference between the maximum value δLmax of the length error δLmax = 0.15 mm and the minimum value of the dimensional error δWmin = 0.01 mm.
　また、最大寸法誤差δｍａｘは、幅の寸法誤差の絶対値と長さの寸法誤差の絶対値うち最大のものである。具体的には、図２０の幅の寸法誤差の最大値δＷｍａｘ（ｍｍ）の絶対値と長さの寸法誤差の最大値δＬｍａｘ（ｍｍ）の絶対値の大きい方である。例えば、サンプルＡ２の場合、最大寸法誤差δｍａｘは、長さの寸法誤差の最大値δＬｍａｘ＝０．１５ｍｍとなる。 The maximum dimension error δmax is the maximum of the absolute value of the width dimension error and the absolute value of the length dimension error. Specifically, the absolute value of the maximum value δWmax (mm) of the width dimension error in FIG. 20 and the absolute value of the maximum value δLmax (mm) of the length dimension error are larger. For example, in the case of the sample A2, the maximum dimensional error δmax is the maximum value δLmax of the length dimensional error = 0.15 mm.
　単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）が大きい、サンプルＡ３及びＡ４では、切断線が切断予定線から大きく外れ蛇行したため、寸法誤差を測定できなかった。 In Samples A3 and A4, in which the amount of change ΔE / T (J / mm 2 / s) in unit irradiation energy per unit time is large, the cutting line was greatly deviated from the planned cutting line, and therefore the dimensional error could not be measured.
　図２０に示すように、サンプルＡ（残留引張応力ＣＴ＝２２ＭＰａ）、サンプルＢ（残留引張応力ＣＴ＝５１ＭＰａ）のいずれにおいても、単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）を小さくする程、寸法誤差幅Δδ（ｍｍ）、寸法誤差の最大値δｍａｘ（ｍｍ）、寸法誤差の平均値δａｖｇ（ｍｍ）のいずれもが小さくなる。つまり、単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）を小さくする程、寸法精度が向上する。 As shown in FIG. 20, in both sample A (residual tensile stress CT = 22 MPa) and sample B (residual tensile stress CT = 51 MPa), the change amount ΔE / T (J / mm) of unit irradiation energy per unit time The smaller the 2 / s), the smaller the dimensional error width Δδ (mm), the maximum dimensional error value δmax (mm), and the average dimensional error value δavg (mm). That is, as the change amount ΔE / T (J / mm 2 / s) of unit irradiation energy per unit time is reduced, the dimensional accuracy is improved.
　図２１は、寸法誤差の最大値δｍａｘの単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ依存性を示すグラフである。図２１の横軸は単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）、縦軸は寸法誤差の最大値δｍａｘ（ｍｍ）を示している。図２１において、三角印はサンプルＡ（残留引張応力ＣＴ＝２２ＭＰａ）、菱形印はサンプルＢ（残留引張応力ＣＴ＝５１ＭＰａ）を示している。 FIG. 21 is a graph showing the dependency ΔE / T dependency of the unit irradiation energy per unit time of the maximum value δmax of the dimensional error. In FIG. 21, the horizontal axis indicates the change amount ΔE / T (J / mm 2 / s) of the unit irradiation energy, and the vertical axis indicates the maximum value δmax (mm) of the dimensional error. In FIG. 21, the triangle mark indicates sample A (residual tensile stress CT = 22 MPa), and the diamond mark indicates sample B (residual tensile stress CT = 51 MPa).
　図２０の表において説明したように、サンプルＡ、サンプルＢのそれぞれについて、単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔ（Ｊ／ｍｍ２／ｓ）を小さくする程、寸法誤差の最大値δｍａｘ（ｍｍ）が小さくなる。また、いずれもほぼ線形に近い関係を有していると考えられる。 As described in the table of FIG. 20, for each of the sample A and the sample B, the smaller the change amount ΔE / T (J / mm 2 / s) of unit irradiation energy per unit time, the maximum value of the dimensional error. δmax (mm) decreases. Moreover, it is thought that all have a relationship close to linearity.
　図２１の結果から、サンプルＡにおいて寸法誤差の最大値δｍａｘ（ｍｍ）を０．１ｍｍ以下とするには、単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔを２００Ｊ／ｍｍ２／ｓ以下とすればよい。サンプルＢにおいて寸法誤差の最大値δｍａｘ（ｍｍ）を０．１ｍｍ以下とするには、単位時間当たりの単位照射エネルギーの変化量ΔＥ／Ｔを８００Ｊ／ｍｍ２／ｓ以下とすればよい。 From the result of FIG. 21, in order to set the maximum value δmax (mm) of the dimensional error in sample A to 0.1 mm or less, the change amount ΔE / T of unit irradiation energy per unit time is 200 J / mm 2 / s or less. do it. In order to set the maximum value δmax (mm) of the dimensional error in the sample B to 0.1 mm or less, the change amount ΔE / T of the unit irradiation energy per unit time may be 800 J / mm 2 / s or less.
　また、サンプルＡとサンプルＢとを比較すると、強化ガラス板の残留引張応力ＣＴが小さい程、単位照射エネルギーの切換速度を低く抑える必要があることが分かる。 Further, comparing sample A and sample B, it is found that the switching rate of unit irradiation energy needs to be kept lower as the residual tensile stress CT of the tempered glass plate is smaller.
　なお、単位時間当たりの単位照射エネルギーの変化量によって変化するのは、主に図１７に示した長手方向両端における幅Ｗ１、Ｗ３、幅方向両端における長さＬ１、Ｌ３である。つまり、長手方向中央部の幅Ｗ２及び幅方向中央部の長さＬ２は影響を受けにくい。従って、寸法誤差との関係を評価する場合、寸法誤差の平均値δａｖｇ（ｍｍ）を用いるよりも、寸法誤差の最大値δｍａｘ（ｍｍ）もしくは寸法誤差幅Δδ（ｍｍ）を用いた方が適切であると推察される。 Note that what changes depending on the amount of change in unit irradiation energy per unit time is mainly the widths W1 and W3 at both ends in the longitudinal direction and the lengths L1 and L3 at both ends in the width direction shown in FIG. That is, the width W2 at the longitudinal center and the length L2 at the width central are less affected. Therefore, when evaluating the relationship with the dimensional error, it is more appropriate to use the maximum dimensional error value δmax (mm) or the dimensional error width Δδ (mm) than to use the average value δavg (mm) of the dimensional error. It is assumed that there is.
（実施の形態２）
　次に、実施の形態２に係る強化ガラス板切断装置について説明する。この装置は実施の形態１に係る強化ガラスの切断方法を実施するためのものである。図２２は、本実施の形態に係る強化ガラス板切断装置を説明するための図である。本実施の形態に係る強化ガラス板切断装置６０は、レーザ出力部６１、ガラス保持部６２、制御部６３、及び制御プログラム生成部６４を有する。 (Embodiment 2)
Next, the tempered glass sheet cutting device according to Embodiment 2 will be described. This apparatus is for carrying out the method for cutting tempered glass according to the first embodiment. FIG. 22 is a diagram for explaining the tempered glass sheet cutting device according to the present embodiment. The tempered glass sheet cutting device 60 according to the present embodiment includes a laser output unit 61, a glass holding unit 62, a control unit 63, and a control program generation unit 64.
　レーザ出力部６１は、強化ガラス板１０を切断するためのレーザ光２０を出力する。レーザ光２０の光源としては、例えば、ＵＶレーザ（波長：３５５ｎｍ）、グリーンレーザ（波長：５３２ｎｍ）、半導体レーザ（波長：８０８ｎｍ、９４０ｎｍ、９７５ｎｍ）、ファイバーレーザ（波長：１０６０～１１００ｎｍ）、ＹＡＧレーザ（波長：１０６４ｎｍ、２０８０ｎｍ、２９４０ｎｍ）などを用いることができる。レーザ出力部６１は、レーザ光の焦点を調整するための光学系を備えている。また、レーザ光の照射部にノズルを配置してもよい。レーザ光のパワー（レーザ出力）、レーザ光のビーム径（焦点）、レーザ照射のタイミングなどは、制御部６３を用いて制御される。 The laser output unit 61 outputs a laser beam 20 for cutting the tempered glass plate 10. Examples of the light source of the laser beam 20 include a UV laser (wavelength: 355 nm), a green laser (wavelength: 532 nm), a semiconductor laser (wavelength: 808 nm, 940 nm, 975 nm), a fiber laser (wavelength: 1060 to 1100 nm), and a YAG laser. (Wavelength: 1064 nm, 2080 nm, 2940 nm) or the like can be used. The laser output unit 61 includes an optical system for adjusting the focus of the laser light. Further, a nozzle may be arranged in the laser light irradiation part. The power of the laser beam (laser output), the beam diameter (focal point) of the laser beam, the timing of laser irradiation, and the like are controlled using the control unit 63.
　ここで、近赤外のレーザ光を用いる場合、近赤外における吸収を増加させるために強化ガラス板にＦｅ等の不純物を添加する必要がある。近赤外において吸収特性を持つ不純物を添加した場合、可視光領域の吸収特性にも影響を与えるため、強化ガラス板の色味や透過率に影響を及ぼす場合がある。このようなことを防止するために、レーザ光２０の光源として、波長が２５００～５０００ｎｍの中赤外のレーザを用いてもよい。波長が２５００～５０００ｎｍの帯域ではガラス自体の分子振動に起因する吸収が発生するため、Ｆｅ等の不純物の添加が不要となる。 Here, when using near-infrared laser light, it is necessary to add impurities such as Fe to the tempered glass plate in order to increase absorption in the near-infrared. When an impurity having an absorption characteristic in the near infrared is added, it also affects the absorption characteristic in the visible light region, and thus may affect the color and transmittance of the tempered glass plate. In order to prevent this, a mid-infrared laser having a wavelength of 2500 to 5000 nm may be used as the light source of the laser light 20. In the wavelength range of 2500 to 5000 nm, absorption due to molecular vibration of the glass itself occurs, so that it is not necessary to add impurities such as Fe.
　ガラス保持部６２は、加工対象である強化ガラス板１０を保持すると共に、強化ガラス板１０を所定の方向に移動する。すなわち、ガラス保持部６２は、レーザ光が強化ガラス板１０の切断予定線を走査するように、強化ガラス板１０を移動する。ガラス保持部６２は、制御部６３を用いて制御される。ガラス保持部６２は、加工対象である強化ガラス板１０を、多孔質板等を用いて吸着することで固定してもよい。また、ガラス保持部６２は、強化ガラス板１０の位置を決定するための画像検出器を備えていてもよい。位置決め用の画像検出器を備えることで、強化ガラス板１０の加工精度を向上させることができる。 The glass holding unit 62 holds the tempered glass plate 10 to be processed and moves the tempered glass plate 10 in a predetermined direction. In other words, the glass holding unit 62 moves the tempered glass plate 10 so that the laser beam scans the planned cutting line of the tempered glass plate 10. The glass holding unit 62 is controlled using the control unit 63. The glass holding part 62 may be fixed by adsorbing the tempered glass plate 10 to be processed using a porous plate or the like. The glass holding unit 62 may include an image detector for determining the position of the tempered glass plate 10. By providing the image detector for positioning, the processing accuracy of the tempered glass plate 10 can be improved.
　なお、図２２に示した強化ガラス板切断装置６０では、レーザ光２０の照射領域が強化ガラス板１０上を移動するように、ガラス保持部６２を用いて強化ガラス板１０を移動している。このとき、レーザ出力部６１は固定されている。しかし、ガラス保持部６２に保持されている強化ガラス板１０を固定し、レーザ出力部６１を移動させることで、レーザ光２０の照射領域を強化ガラス板１０上において移動させてもよい。また、ガラス保持部６２に保持されている強化ガラス板１０とレーザ出力部６１の両方が移動するように構成してもよい。 In the tempered glass sheet cutting apparatus 60 shown in FIG. 22, the tempered glass sheet 10 is moved using the glass holding part 62 so that the irradiation region of the laser beam 20 moves on the tempered glass sheet 10. At this time, the laser output unit 61 is fixed. However, the irradiation region of the laser beam 20 may be moved on the tempered glass plate 10 by fixing the tempered glass plate 10 held by the glass holding unit 62 and moving the laser output unit 61. Moreover, you may comprise so that both the tempered glass board 10 currently hold | maintained at the glass holding | maintenance part 62 and the laser output part 61 may move.
　制御部６３は、レーザ出力部６１及びガラス保持部６２を、制御プログラム生成部６４で生成された制御プログラムに基づき制御する。 The control unit 63 controls the laser output unit 61 and the glass holding unit 62 based on the control program generated by the control program generation unit 64.
　制御プログラム生成部６４は、予め設定された強化ガラス板１０の物性（熱膨張係数、厚さ、レーザ光に対する強化ガラス板の吸収係数、強化ガラス板の中間層１７の残留引張応力など）に応じて、直線部及びコーナー部を切断する際に強化ガラス板に照射される単位照射エネルギーＥ１、Ｅ２をそれぞれ決定する。そして、この決定された単位照射エネルギーＥ１、Ｅ２となるように、レーザ光のビーム径、レーザ光の出力、及びレーザ光の走査速度を制御する制御プログラムを生成する。 The control program generation unit 64 corresponds to preset physical properties of the tempered glass plate 10 (thermal expansion coefficient, thickness, absorption coefficient of the tempered glass plate with respect to laser light, residual tensile stress of the intermediate layer 17 of the tempered glass plate, etc.). Then, unit irradiation energies E1 and E2 that are applied to the tempered glass plate when the straight part and the corner part are cut are determined. And the control program which controls the beam diameter of a laser beam, the output of a laser beam, and the scanning speed of a laser beam is produced | generated so that it may become these determined unit irradiation energy E1 and E2.
　また、制御プログラム生成部６４は、コーナー部入口での単位照射エネルギーＥ１からＥ２への切換速度及び、コーナー部出口での単位照射エネルギーＥ２からＥ１への切換速度を制御するための制御プログラムを生成する。つまり、コーナー部出口での単位照射エネルギーＥ２からＥ１への切換速度が、コーナー部入口での単位照射エネルギーＥ１からＥ２への切換速度よりも小さくなるように、レーザ出力部６１及びガラス保持部６２を制御するための制御プログラムを生成する。具体的には、単位照射エネルギーの切換速度を制御するために、レーザ光のビーム径、レーザ光の出力、及びレーザ光の走査速度などの切換速度を制御する制御プログラムを生成する。 The control program generation unit 64 generates a control program for controlling the switching speed from the unit irradiation energy E1 to E2 at the corner entrance and the switching speed from the unit irradiation energy E2 to E1 at the corner exit. To do. That is, the laser output unit 61 and the glass holding unit 62 are configured such that the switching speed from the unit irradiation energy E2 to E1 at the corner portion outlet is smaller than the switching speed from the unit irradiation energy E1 to E2 at the corner portion entrance. A control program for controlling the system is generated. Specifically, in order to control the switching speed of the unit irradiation energy, a control program for controlling the switching speed such as the beam diameter of the laser light, the output of the laser light, and the scanning speed of the laser light is generated.
　以上に説明したように、本発明の実施の形態により、切り出された強化ガラスパネルの寸法不良を抑制した強化ガラス板の切断方法、及び強化ガラス板切断装置を提供することができる。 As described above, according to the embodiment of the present invention, it is possible to provide a method for cutting a tempered glass sheet and a tempered glass sheet cutting apparatus that suppress the dimensional defects of the cut out tempered glass panel.
　以上、本発明を上記実施形態に即して説明したが、上記実施形態の構成にのみ限定されるものではなく、本願特許請求の範囲の請求項の発明の範囲内で当業者であればなし得る各種変形、修正、組み合わせを含むことは勿論である。 Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the configuration of the above embodiment, and can be made by those skilled in the art within the scope of the invention of the claims of the claims of the present application. It goes without saying that various modifications, corrections, and combinations are included.
　この出願は、２０１１年１２月７日に出願された日本出願特願２０１１－２６７７４７及び２０１２年７月９日に出願された日本出願特願２０１２－１５３４００を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2011-267747 filed on Dec. 7, 2011 and Japanese Application No. 2012-153400 filed on Jul. 9, 2012. The entire disclosure is incorporated herein.
１０　強化ガラス板
１２　表面
１３　表面層
１４　裏面
１５　裏面層
１７　中間層
２０　レーザ光
２２　照射領域
３０　クラック
３４　切断予定線
４０　強化ガラスパネル
４１、４２、４３、４４　直線部
４５　切断開始位置
４６　切断終了位置
６０　強化ガラス板切断装置
６１　レーザ出力部
６２　ガラス保持部
６３　制御部
６４　制御プログラム生成部
Ｃ１、Ｃ２、Ｃ３、Ｃ４　コーナー部 DESCRIPTION OF SYMBOLS 10 Tempered glass board 12 Front surface 13 Front surface layer 14 Back surface 15 Back surface layer 17 Intermediate layer 20 Laser beam 22 Irradiation area 30 Crack 34 Planned cutting line 40 Tempered glass panel 41, 42, 43, 44 Straight line portion 45 Cutting start position 46 Cutting end position 60 tempered glass sheet cutting device 61 laser output unit 62 glass holding unit 63 control unit 64 control program generation unit C1, C2, C3, C4 corner unit

Claims (13)

  1. 　残留圧縮応力を有する表面層および裏面層と、当該表面層および裏面層との間に形成され、内部残留引張応力ＣＴ（ＭＰａ）を有する中間層とを備える強化ガラス板を、当該強化ガラス板に照射されるレーザ光の照射領域を移動させることで切断する強化ガラス板の切断方法であって、
    　前記表面層および前記裏面層の厚さをＤＯＬ（μｍ）、前記強化ガラス板の厚さをｔ１（μｍ）、前記強化ガラス板のヤング率をＹ（ＭＰａ）として、下式で表現される前記内部残留引張応力ＣＴに基づく単位面積当たりのひずみエネルギーＵＣＴ（Ｊ／ｍ２）を２．５Ｊ／ｍ２以上とし、
    　前記強化ガラス板の切断線がコーナー部と直線部とを含み、前記直線部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ１よりも、前記コーナー部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ２を大きくし、
    　前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を、前記直線部における前記照射エネルギーＥ１から前記コーナー部における前記照射エネルギーＥ２への切換速度よりも小さくする、強化ガラス板の切断方法。
           ＵＣＴ＝｛ＣＴ２×（ｔ１－２×ＤＯＬ)｝／（２×Ｙ）     A tempered glass plate comprising a surface layer and a back surface layer having a residual compressive stress, and an intermediate layer formed between the surface layer and the back surface layer and having an internal residual tensile stress CT (MPa) is applied to the tempered glass plate. A method of cutting a tempered glass plate that is cut by moving the irradiation region of the irradiated laser beam,
    The thickness of the surface layer and the back surface layer is DOL (μm), the thickness of the tempered glass plate is t 1 (μm), and the Young's modulus of the tempered glass plate is Y (MPa). The strain energy U CT (J / m 2 ) per unit area based on the internal residual tensile stress CT is 2.5 J / m 2 or more,
    The cutting line of the tempered glass plate includes a corner portion and a straight portion, and the tempered glass at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated on the tempered glass plate at the straight portion. Increasing the irradiation energy E2 per unit irradiation area of the laser beam irradiated to the plate,
    The switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. Cutting method of glass plate.
    U CT = {CT 2 × (t 1 −2 × DOL)} / (2 × Y)
  2. 　前記強化ガラス板に入射される前記レーザ光の実効的な出力をＰｅ（Ｗ）、前記レーザ光の走査速度をｖ（ｍｍ／ｓ）、前記レーザ光に対する前記強化ガラス板の吸収係数をα（ｍｍ－１）、前記強化ガラス板の厚さをｔ２（ｍｍ）、前記強化ガラス板の線膨張係数をαＬ（Ｋ－１）、前記強化ガラス板の密度をρ（ｇ／ｍｍ３）、前記強化ガラス板の比熱をｃ（Ｊ／ｇ／Ｋ）として、下式で表現される切断指数Ｋ（Ｎ／ｍｍ）を１５０Ｎ／ｍｍ以下とする、請求項１に記載の強化ガラス板の切断方法。
           Ｋ＝Ｐｅ／ｖ×ｅｘｐ（－α×ｔ２）×（Ｙ×αＬ）／（ｔ２×ρ×ｃ）     The effective output of the laser light incident on the tempered glass plate is Pe (W), the scanning speed of the laser light is v (mm / s), and the absorption coefficient of the tempered glass plate with respect to the laser light is α ( mm −1 ), the thickness of the tempered glass plate is t 2 (mm), the linear expansion coefficient of the tempered glass plate is α L (K −1 ), and the density of the tempered glass plate is ρ (g / mm 3 ). The specific heat of the tempered glass sheet is c (J / g / K), and the cutting index K (N / mm) expressed by the following formula is 150 N / mm or less. Cutting method.
    K = Pe / v × exp (−α × t 2 ) × (Y × α L ) / (t 2 × ρ × c)
  3. 　前記強化ガラス板と前記レーザ光とが、前記レーザ光に対する前記強化ガラス板の吸収係数をα（ｍｍ－１）、前記強化ガラス板の厚さをｔ２（ｍｍ）として、０＜α×ｔ２≦３．０の条件を満たす、請求項１または２に記載の強化ガラス板の切断方法。 The tempered glass plate and the laser beam are expressed as follows: 0 <α × t, where α (mm −1 ) is the absorption coefficient of the tempered glass plate with respect to the laser beam and t 2 (mm) is the thickness of the tempered glass plate. The cutting method of the tempered glass board of Claim 1 or 2 which satisfy | fills the conditions of 2 <= 3.0.
  4. 　前記中間層の残留引張応力が大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を大きくする、
    請求項１～３のいずれか一項に記載の強化ガラス板の切断方法。     As the residual tensile stress of the intermediate layer increases, the switching speed from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the linear portion is increased.
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 3.
  5. 　前記レーザ光の照射領域の移動速度を速くすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行う、
    請求項１～４のいずれか一項に記載の強化ガラス板の切断方法。     Switching from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the straight portion by increasing the moving speed of the irradiation region of the laser light,
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 4.
  6. 　前記レーザ光の出力を小さくすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行う、
    請求項１～５のいずれか一項に記載の強化ガラス板の切断方法。     By reducing the output of the laser beam, the irradiation energy E2 at the corner portion is switched to the irradiation energy E1 at the straight portion.
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 5.
  7. 　前記レーザ光の照射領域の面積を大きくすることにより、前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換を行う、
    請求項１～６のいずれか一項に記載の強化ガラス板の切断方法。     Switching from the irradiation energy E2 at the corner portion to the irradiation energy E1 at the linear portion by increasing the area of the laser light irradiation region,
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 6.
  8. 　前記強化ガラス板の吸収係数αが大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を小さくする、
    請求項１～７のいずれか一項に記載の強化ガラス板の切断方法。     As the absorption coefficient α of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 7.
  9. 　前記強化ガラス板の熱膨張係数が大きくなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を小さくする、
    請求項１～８のいずれか一項に記載の強化ガラス板の切断方法。     As the thermal expansion coefficient of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are reduced.
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 8.
  10. 　前記強化ガラス板の厚さが厚くなるにつれて、前記コーナー部における前記照射エネルギーＥ２及び前記直線部における前記照射エネルギーＥ１を大きくする、
    請求項１～９のいずれか一項に記載の強化ガラス板の切断方法。     As the thickness of the tempered glass plate increases, the irradiation energy E2 at the corner portion and the irradiation energy E1 at the straight portion are increased.
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 9.
  11. 　前記強化ガラス板の前記レーザ光の照射領域に、前記レーザ光の入射側から気体を吹き付けて冷却する、
    請求項１～１０のいずれか一項に記載の強化ガラス板の切断方法。     Cooling by blowing a gas from the laser light incident side to the laser light irradiation region of the tempered glass plate,
    The method for cutting a strengthened glass sheet according to any one of claims 1 to 10.
  12. 　前記強化ガラス板の前記コーナー部に、前記レーザ光の出射側から気体を吹き付けて冷却する、
    請求項１１に記載の強化ガラス板の切断方法。     Cooling by blowing gas from the laser light emission side to the corner of the tempered glass plate,
    The cutting method of the tempered glass board of Claim 11.
  13. 　残留圧縮応力を有する表面層および裏面層と、当該表面層および裏面層との間に形成され、内部残留引張応力を有する中間層とを備える強化ガラス板を、当該強化ガラス板に照射されるレーザ光の照射領域を移動させることで切断する強化ガラス板切断装置であって、
    　前記強化ガラス板を保持するガラス保持部と、
    　前記強化ガラス板を切断するためのレーザ光を出力するレーザ出力部と、
    　前記レーザ出力部を制御する制御部と、を備え、
    　前記強化ガラス板の切断線がコーナー部と直線部とを含み、
    　前記制御部は、
    　前記直線部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ１よりも、前記コーナー部において前記強化ガラス板に照射されるレーザ光の単位照射面積あたりの照射エネルギーＥ２を大きくし、
    　前記コーナー部における前記照射エネルギーＥ２から前記直線部における前記照射エネルギーＥ１への切換速度を、前記直線部における前記照射エネルギーＥ１から前記コーナー部における前記照射エネルギーＥ２への切換速度よりも小さくする、強化ガラス板切断装置。     Laser that irradiates the tempered glass plate with a tempered glass plate that is formed between the surface layer and the back surface layer having a residual compressive stress and an intermediate layer that has an internal residual tensile stress. A tempered glass sheet cutting device that cuts by moving an irradiation area of light,
    A glass holding part for holding the tempered glass plate;
    A laser output unit for outputting a laser beam for cutting the tempered glass plate;
    A control unit for controlling the laser output unit,
    The cutting line of the tempered glass plate includes a corner portion and a straight portion,
    The controller is
    The irradiation energy E2 per unit irradiation area of the laser light irradiated to the tempered glass plate at the corner portion is more than the irradiation energy E1 per unit irradiation area of the laser light irradiated to the tempered glass plate at the linear portion. Make it bigger
    The switching speed from the irradiation energy E2 in the corner portion to the irradiation energy E1 in the straight portion is made smaller than the switching speed from the irradiation energy E1 in the straight portion to the irradiation energy E2 in the corner portion. Glass plate cutting device.
PCT/JP2012/081371 2011-12-07 2012-12-04 Method for cutting toughened glass plates and device for cutting toughened glass plates WO2013084879A1 (en)

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JP2011-267747 2011-12-07
JP2011267747A JP2015034096A (en) 2011-12-07 2011-12-07 Cutting method for strengthened glass plate and strengthened glass plate cutting device
JP2012153400 2012-07-09
JP2012-153400 2012-07-09

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US11078112B2 (en) 2017-05-25 2021-08-03 Corning Incorporated Silica-containing substrates with vias having an axially variable sidewall taper and methods for forming the same
US11114309B2 (en) 2016-06-01 2021-09-07 Corning Incorporated Articles and methods of forming vias in substrates
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US11556039B2 (en) 2013-12-17 2023-01-17 Corning Incorporated Electrochromic coated glass articles and methods for laser processing the same
US11148225B2 (en) 2013-12-17 2021-10-19 Corning Incorporated Method for rapid laser drilling of holes in glass and products made therefrom
US11697178B2 (en) 2014-07-08 2023-07-11 Corning Incorporated Methods and apparatuses for laser processing materials
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US11062986B2 (en) 2017-05-25 2021-07-13 Corning Incorporated Articles having vias with geometry attributes and methods for fabricating the same
US11972993B2 (en) 2017-05-25 2024-04-30 Corning Incorporated Silica-containing substrates with vias having an axially variable sidewall taper and methods for forming the same
US11554984B2 (en) 2018-02-22 2023-01-17 Corning Incorporated Alkali-free borosilicate glasses with low post-HF etch roughness
US11629088B2 (en) 2018-06-19 2023-04-18 Corning Incorporated Actively controlled laser processing of transparent workpieces
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US20200353570A1 (en) * 2019-05-07 2020-11-12 Topapex Optronics Technology Co.,Ltd. Multi-laser cutting method and system thereof

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