JP2015171955A - Method for manufacturing curved plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a curved plate capable of attaining a desired shape.SOLUTION: A curved plate-manufacturing method comprises: a forming step of bend-forming a glass plate softened by heating; a reinforcing step of reinforcing a front surface and a rear surface of the glass plate bend-formed; and a cutting step of irradiating the reinforced glass plate 10 locally with a laser beam thereby to move the irradiation position of the laser beam 20 in the reinforced glass plate 10, to extend a crack 30 penetrating in the plate thickness direction through the reinforced glass plate 10 thereby to cut off the curved plate from the reinforced glass plate 10. At the cutting step, an intermediate layer 17 is locally heated at a temperature at or lower than an annealing temperature by the laser beam 20 thereby to establish either a tensile stress lower than the internal residual tensile stress CT or a compression stress locally in the intermediate layer 17 and to control the extension rate of the crack 30 by the internal residual tensile stress.

Description

  The present invention relates to a method for manufacturing a curved plate.

  Examples of the strengthening method for strengthening glass include a physical strengthening method such as an air cooling strengthening method and a chemical strengthening method such as an ion exchange method. The tempered glass plate is one in which residual compressive stress is generated on the front and back surfaces of the glass plate and the front and back surfaces of the glass plate are strengthened.

  Conventionally, it is difficult to cut a tempered glass plate, and a curved plate, which is a bending tempered glass plate, has been manufactured by cutting a glass plate into a product size, bending it, and then strengthening (for example, patents) Reference 1).

JP 2000-72461 A

  FIG. 1 is an explanatory diagram (1) of glass sheet bending. FIG. 2 is a cross-sectional view showing the glass plate of FIG. As shown in FIG. 1, when the glass plate 1 softened by heating is bent, a tensile stress is generated along the curved surface 2 of the glass plate 1, and a compressive stress corresponding to the tensile stress and Poisson's ratio is generated. Occurs in a direction perpendicular to the curve. On the other hand, on the concave curved surface 3 of the glass plate 1, compressive stress is generated along the curve, and tensile stress corresponding to the compressive stress and Poisson's ratio is generated in a direction perpendicular to the curve. As described above, different stress fields are formed on the convex curved surface 2 and the concave curved surface 3, and there is a problem that both ends 1a and 1b of the glass plate 1 warp in unintended directions as shown in FIG. The both ends 1a and 1b of the glass plate 1 are warped because the end of the glass plate 1 is a free end and thus is more freely movable than the inside of the glass plate 1.

  FIG. 3 is an explanatory view (2) of the bending of the glass plate. In FIG. 3, the glass plate 1 is bent while the glass plate 1 softened by heating is conveyed by a plurality of conveying rollers 4. The plurality of transport rollers 4 form a curved upwardly inclined transport path. Since the front end 1c and the rear end 1d of the glass plate 1 are free ends, bending stress is hardly generated at the front end 1c and the rear end 1d, and insufficient bending is likely to occur at the front end 1c and the rear end 1d.

  FIG. 4 is an explanatory view (3) of the bending of the glass plate. In FIG. 4, when the glass plate 1 is bent while the glass plate 1 is conveyed by the plurality of conveyance rolls 4, the plurality of conveyance rolls 4 are moved up and down so that the conveyance path of the glass plate 1 becomes a traveling wave. Similar to the method of FIG. 3, this method also tends to cause insufficient bending at the front end 1c and the rear end 1d of the glass plate 1.

  FIG. 5 is an explanatory view (4) of glass sheet bending. As shown in FIG. 5, when the through-hole 1e is formed in the edge part of the glass plate 1, it is hard to produce bending stress in the peripheral part 1f of the through-hole 1e, and it is easy to produce insufficient bending. The glass plate 1 is, for example, a vehicle window glass, and the through hole 1e is, for example, a wiper hole.

  FIG. 6 is an explanatory view (5) of glass sheet bending. As shown in FIG. 6, when a part of the outer periphery of the glass plate 1 is recessed, the convex portion 1g of the glass plate 1 is unlikely to generate bending stress and is likely to be insufficiently bent. The glass plate 1 is, for example, a vehicle window glass.

  Thus, in the bending of a glass plate, problems such as unintended warping and insufficient bending are likely to occur, and it is difficult to produce a glass plate having a desired shape.

  Conventionally, since it has been difficult to cut a tempered glass plate, a bent plate, which is a bending tempered glass plate, has been manufactured by cutting a glass plate into a product size, bending it, and then strengthening it. When a glass plate having a product size is bent, problems such as warping and insufficient bending occur as described above, and it is difficult to obtain a curved plate having a desired shape.

  This invention is made | formed in view of the said subject, Comprising: It aims at provision of the manufacturing method of the curved board from which the desired shape is obtained.

In order to solve the above problems, a method for manufacturing a curved plate according to one aspect of the present invention includes:
A molding process for bending a glass sheet softened by heating;
Front and back layers as reinforcing layers having a residual compressive stress by reinforcing the front and back surfaces of the bent glass plate, and an intermediate layer having an internal residual tensile stress formed between the front and back layers A tempering step for producing a tempered glass plate comprising:
Moving the irradiation position of the laser light in the tempered glass plate, extending a crack penetrating the tempered glass plate in the thickness direction, and cutting the curved plate from the tempered glass plate,
In the cutting step, the intermediate layer is locally heated by the laser light at a temperature below the annealing point, and a tensile stress or a compressive stress smaller than the internal residual tensile stress is locally generated in the intermediate layer. The crack extension speed due to the internal residual tensile stress is controlled.

  According to the present invention, a method of manufacturing a curved plate that provides a desired shape is provided.

It is explanatory drawing (1) of the bending shaping | molding of a glass plate. It is sectional drawing which cut | disconnects and shows the glass plate of FIG. It is explanatory drawing (2) of the bending shaping | molding of a glass plate. It is explanatory drawing (3) of the bending shaping | molding of a glass plate. It is explanatory drawing (4) of the bending shaping | molding of a glass plate. It is explanatory drawing (5) of the bending shaping | molding of a glass plate. It is sectional drawing which shows an example of a tempered glass board. It is a schematic diagram which shows an example of the residual stress distribution of an air-cooled tempered glass board. It is a schematic diagram which shows an example of the residual stress distribution of a chemically strengthened glass plate. It is explanatory drawing of the cutting process by 1st Embodiment of this invention. It is a figure which shows an example of the relationship between the irradiation position of the laser beam in a tempered glass board, and the front-end | tip position of a crack. It is a schematic diagram which shows an example of the stress distribution in the cross section along the AA line of FIG. It is a schematic diagram which shows an example of the stress distribution in the cross section along the BB line of FIG. It is a figure which shows an example of the cutting-out position of the curved board cut out from a tempered glass board. It is a figure which shows another example of the cutting-out position of the curved board cut out from a tempered glass board. It is a figure which shows the protection process by 1st Embodiment of this invention. It is explanatory drawing of the cutting process by 2nd Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

[First Embodiment]
The manufacturing method of the curved plate which is a bending strengthening glass plate has a formation process, a reinforcement | strengthening process, and a cutting process in this order.

  In the forming step, a glass plate softened by heating is bent. There are a variety of bending methods, such as roll forming shown in FIGS. 3 and 4, gravity forming in which the outer periphery of the glass plate is supported by a ring, and the glass plate is bent by its own weight, and the glass plate is pressed against the mold. Any of press forming that bends along a vacuum and vacuum forming that a glass plate is vacuum-adsorbed with a mold and bent along the mold may be used. These molding methods can also be used in combination. For example, a combination of press molding and vacuum molding, a combination of press molding and gravity molding, or the like is possible.

  In the tempering step, residual tensile stress is generated on the front and back surfaces of the bent glass plate, the front and back surfaces of the glass plate are strengthened, and a tempered glass plate is produced. The strengthening method may be either a physical strengthening method such as an air cooling strengthening method or a chemical strengthening method such as an ion exchange method.

  The air-cooling strengthening method rapidly cools the glass plate at the temperature near the softening point from both sides, and creates a temperature difference between the front and back surfaces of the glass plate and the inside of the glass plate. Residual compressive stress is generated, and the front and back surfaces of the glass plate are strengthened.

  In the ion exchange method, the front and back surfaces of a glass plate 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). Thereby, a residual compressive stress is produced in the surface and back surface of a glass plate, and the surface and back surface of a glass plate are strengthened.

  Although the kind of glass of a glass plate is not specifically limited, For example, soda-lime glass, an alkali free glass etc. are mentioned. The thickness of a glass plate is suitably set according to the use of a glass plate, for example, is 0.1-25 mm. In the case of a tempered glass plate by physical strengthening, it is preferable that the thickness is 1.5 mm or more because a temperature difference is easily made between the front and back surfaces of the glass plate and the inside in the strengthening step.

  FIG. 7 is a diagram illustrating an example of a cross section of a tempered glass plate. In FIG. 7, the direction of the arrow indicates the acting direction of the residual stress, and the size of the arrow indicates the magnitude of the stress.

  The tempered glass plate 10 includes a surface layer 13 and a back surface layer 15 as reinforcing layers having residual compressive stress, and an intermediate layer 17 formed between the surface layer 13 and the back surface layer 15 and having residual tensile stress.

  The end surface of the tempered glass plate 10 may be covered with a reinforcing layer extending from the end portion of the surface layer 13 and the end portion of the back surface layer 15. Further, the end face of the tempered glass plate 10 may not be covered with the tempered layer, and the end face of the intermediate layer 17 may be exposed at the end face of the tempered glass plate 10.

  FIG. 8 is a schematic diagram showing an example of the residual stress distribution of the air-cooled tempered glass sheet. FIG. 9 is a schematic diagram showing an example of a residual stress distribution of a chemically strengthened glass plate.

  As shown in FIGS. 8 and 9, the residual compressive stress decreases as it goes from the both ends in the thickness direction of the tempered glass plate 10 toward the inside, and a residual tensile stress is generated inside the tempered glass plate 10.

  8 and 9, CS is the maximum residual compressive stress (surface compressive stress) (> 0) of the reinforcing layers 13 and 15, CT is the internal residual tensile stress (> 0) in the intermediate layer 17, DOL is the reinforcing layer 13, A thickness of 15 is shown respectively. CS, CT, and DOL are the tempering conditions (in the case of air-cooled tempering method, the heating temperature and cooling rate of the glass plate, in the case of ion exchange method, the concentration and temperature of the processing solution, and the glass plate to the processing solution. The immersion time can be adjusted.

  The surface compressive stress (CS) of the reinforcing layers 13 and 15 and the thickness (DOL) of the reinforcing layers 13 and 15 are measured by, for example, a surface stress meter FSM-6000 (manufactured by Orihara Seisakusho).

In the case of a chemically strengthened glass plate, the internal residual tensile stress (CT) of the intermediate layer 17 is calculated by the following mathematical formula (1).
CT = (CS × DOL) / (t−2 × DOL) (1)
In addition, when the surface layer 13 and the back surface layer 15 have different thicknesses and different maximum compressive stresses, the internal residual tensile stress (CT) is calculated by the following mathematical formula (2).
CT = (C1 × D1 / 2 + C2 × D2 / 2) / (t−D1−D2) (2)
In the above formula (2), C1 represents the maximum residual compressive stress of the surface layer 13, D1 represents the thickness of the surface layer 13, C2 represents the maximum residual compressive stress of the back surface layer 15, and D2 represents the thickness of the back surface layer 15.

In the case of a physically strengthened glass plate, the internal residual tensile stress (CT) of the intermediate layer 17 is calculated by the following mathematical formula (3).
CT = CS / a (3)
In Equation (3), a is a constant determined by the temperature at the start of cooling the glass plate, the cooling rate of the glass, the thickness of the glass plate, etc., and is usually in the range of 2.0 to 2.5.

  FIG. 10 is an explanatory diagram of the cutting process according to the first embodiment of the present invention. FIG. 11 is a diagram illustrating an example of the relationship between the irradiation position of the laser beam on the tempered glass plate and the tip position of the crack.

In the cutting step, the curved plate is cut out from the tempered glass plate 10. The curved plate may be at least partially curved and may be partially flat. In the cutting step, the tempered glass plate 10 is irradiated with the laser beam 20 locally, and the laser 20 in the tempered glass plate 10 is irradiated. The irradiation position is moved, and the crack 30 penetrating the tempered glass plate 10 in the thickness direction is extended. The crack 30 extends along the locus of the irradiation position of the laser 20 on the tempered glass plate 10. In order to move the irradiation position of the laser 20 on the tempered glass plate 10, the tempered glass plate 10 may move, the light source of the laser light 20 may move, or both may move. Instead of moving the tempered glass plate 10, the tempered glass plate 10 may be rotated. Further, in order to move the irradiation position of the laser 20 on the tempered glass plate 10, a galvanometer mirror that reflects the laser light from the light source toward the tempered glass plate 10 may be rotated.

  The crack 30 penetrates the tempered glass plate 10 in the plate thickness direction, and the cutting of this embodiment is a so-called full cut cutting.

  A scribe line (groove line) may not be formed at the cutting position of the tempered glass plate 10 before laser irradiation. A scribe line may be formed, but it takes time to form the scribe line. Moreover, the tempered glass board 10 may be missing when forming the scribe line.

  An initial crack may be formed at the cutting start position of the tempered glass plate 10. The initial crack is formed by, for example, a cutter, a file, or a laser. When the end surface of the tempered glass plate 10 is ground with a grindstone or the like, microcracks formed by grinding can be used as initial cracks.

  The cutting start position and the cutting end position of the tempered glass plate 10 may be either the outer periphery of the tempered glass plate 10 or the inside of the tempered glass plate 10. Moreover, the shape of the cutting line of the tempered glass plate 10 may be various.

  After being emitted from the light source, the laser light 20 is collected by an optical system such as a condenser lens, is incident on the front surface 12 of the tempered glass plate 10, and is emitted from the rear surface 14 of the tempered glass plate 10.

Assuming that the intensity of the laser beam 20 on the surface 12 of 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 (cm) is I, I = I ₀ × exp The equation (−α × L) is established. This equation is called Lambert-Beer's law. α represents the absorption coefficient (cm ⁻¹ ) of the tempered glass plate 10 with respect to the laser light 20, and is determined by the wavelength of the laser light 20, the chemical composition of the tempered glass plate 10, and the like. α is measured by an ultraviolet visible near infrared spectrophotometer or the like.

  While the laser beam 20 passes through the tempered glass plate 10, the tempered glass plate 10 absorbs part of the irradiation energy of the laser beam 20 as heat, and thermal stress is generated in the tempered glass plate 10. Using this thermal stress, cutting of the tempered glass plate 10 is controlled.

  By the way, the cutting mechanism of the tempered glass plate 10 and the cutting of the non-tempered glass of the present embodiment are fundamentally different, and the manner of crack extension is completely different.

  In cutting the non-strengthened glass plate, the glass plate is locally heated with laser light, and the irradiation position of the laser light on the glass plate is moved to form a temperature gradient along the moving direction. A tensile stress is generated in the vicinity of the rear of the irradiation position of the laser beam, and the crack extends due to this tensile stress. The tip position of the crack follows the irradiation position of the laser light as the irradiation position of the laser light moves. As described above, the extension of the crack is performed only by the irradiation energy of the laser beam. Therefore, if laser irradiation is interrupted in the middle of cutting, the extension of cracks stops.

  On the other hand, in the cutting of tempered glass of this embodiment, in order to utilize the residual tensile stress originally present inside the glass plate, the tensile stress is not generated by laser light as in the case of cutting of non-tempered glass. May be. Further, when a crack is generated by applying some force to the tempered glass plate, the crack extends by itself due to residual tensile stress. Moreover, since the residual tensile stress inside the glass plate exists in the entire glass plate, the crack can extend in any direction. Further, when the crack extension speed reaches a certain speed, the crack branches.

  According to the knowledge of the present inventor, when the internal residual tensile stress (CT) of the intermediate layer 17 becomes 30 MPa or more, the crack formed in the tempered glass plate 10 is naturally extended only by the residual tensile stress of the intermediate layer 17 ( Self-propelled).

  Therefore, in the present embodiment, the intermediate layer 17 is locally heated at a temperature equal to or lower than the annealing point by the laser light 20 while cutting the tempered glass plate 10 by extending the crack 30 due to the internal residual tensile stress CT. A tensile stress or a compressive stress smaller than the internal residual tensile stress CT is locally generated in the intermediate layer 17 to suppress the extension of the crack 30 due to the internal residual tensile stress CT. That is, the extension speed of the crack 30 can be controlled by controlling the moving speed of the irradiation position of the laser beam 20. By controlling the extension speed of the crack 30, the direction in which the crack 30 extends can be determined, and the crack 30 can be prevented from branching. That is, by controlling the crack extension speed, the extension locus of the crack 30 can be controlled with high accuracy. The reason why the intermediate layer 17 is heated at a temperature equal to or lower than the annealing point is that when the heating exceeds the annealing point, the thermal stress is relieved by the viscous flow of the glass plate.

  FIG. 12 is a schematic diagram illustrating an example of a stress distribution in a cross section taken along the line AA of FIG. FIG. 13 is a schematic diagram illustrating an example of a stress distribution in a cross section taken along line BB in FIG. The cross section in FIG. 13 is a cross section behind the cross section in FIG. Here, “rear” means the rear in the moving direction of the irradiation position of the laser light on the tempered glass plate (that is, the rearward direction of the crack in the tempered glass plate). 12 and 13, the direction of the arrow indicates the direction of the applied stress, and the length of the arrow indicates the magnitude of the stress.

  As shown in FIG. 12, the laser-irradiated portion of the intermediate layer 17 is heated to a higher temperature than the other portions of the intermediate layer 17. Therefore, a tensile stress or a compressive stress smaller than the internal residual tensile stress CT is generated in the laser irradiated portion of the intermediate layer 17, and the extension of the crack 30 due to the internal residual tensile stress CT is suppressed. If compressive stress is generated as shown in FIG. 12, extension of the crack 30 can be reliably prevented. On the other hand, when a tensile stress smaller than the internal residual tensile stress CT is generated, the tip position of the crack 30 and the irradiation position of the laser beam 20 are close to each other, and the tip position of the crack 30 can be accurately controlled.

  In contrast, as shown in FIG. 13, the vicinity of the rear part of the laser irradiation portion of the intermediate layer 17 has a lower temperature than the laser irradiation portion of the intermediate layer 17. Therefore, a tensile stress larger than the internal residual tensile stress CT is generated in the vicinity of the rear of the laser irradiation portion of the intermediate layer 17. The crack 30 is formed in a portion where the tensile stress exceeds a predetermined value, and is concentrated in a portion where the tensile stress is large. Therefore, the tip position of the crack 30 does not deviate from the locus of the irradiation position of the laser beam 20.

  The tip position of the crack 30 follows the irradiation position of the laser beam 20 as the irradiation position of the laser beam 20 moves, and does not overtake the irradiation position of the laser beam 20. The tip position of the crack 30 may partially overlap the irradiation position of the laser light 20 as long as it does not pass the irradiation position of the laser light 20.

  As described above, according to the present embodiment, the intermediate layer 17 is locally heated by the laser beam 20, and a tensile stress or a compressive stress smaller than the internal residual tensile stress CT is locally generated in the intermediate layer 17, The extension of the crack 30 due to the internal residual tensile stress CT is suppressed. Therefore, the tip position of the crack 30 can be controlled with high accuracy, and the cutting accuracy can be improved.

  In addition, as shown in FIG. 12, the laser irradiation part of the reinforcement layers 13 and 15 is heated, and becomes higher temperature than the other part of the reinforcement layers 13 and 15. FIG. Therefore, a compressive stress larger than the residual compressive stress shown in FIGS. 7 to 9 is generated in the laser irradiated portions of the reinforcing layers 13 and 15, and the extension of the crack 30 is suppressed.

  In the present embodiment, not only the reinforcing layers 13 and 15 but also the intermediate layer 17 is heated by the laser light 20, so that the laser light 20 having a high internal transmittance is used. Assuming that the moving distance of the laser light 20 from entering the tempered glass plate 10 to exiting is M, α × M is 3.0 or less (that is, the internal transmittance of the laser light is 5% or more). It is preferable.

  When α × M exceeds 3.0, most of the irradiation energy of the laser light 20 is absorbed as heat in the vicinity of the surface 12 of the tempered glass plate 10, and a steep temperature gradient is generated in the plate thickness direction. The laser irradiation portion of the surface layer 13 becomes significantly higher in temperature than the laser irradiation portion of the intermediate layer 17, and a tensile stress larger than the internal residual tensile stress CT is generated in the laser irradiation portion of the intermediate layer 17. Therefore, the tip position of the crack 30 overtakes the irradiation position of the laser beam 20.

  α × M is more preferably 0.3 or less (laser light internal transmittance of 74% or more), further preferably 0.105 or less (laser light internal transmittance of 90% or more), and particularly preferably 0.02 or less. (Internal transmittance of laser beam is 98% or more).

  When the laser beam 20 is perpendicularly incident on the surface 12 of the tempered glass plate 10, the moving distance M of the laser beam 20 has the same value (M = t) as the plate thickness t of the tempered glass plate 10. On the other hand, when the laser beam 20 is incident obliquely on the surface 12 of the tempered glass plate 10, it is refracted according to Snell's law. Assuming that the refraction angle is γ, the moving distance M of the laser light 20 is approximately obtained by the equation M = t / cos γ.

  The internal residual tensile stress CT is preferably 15 MPa or more so that the extension of the crack 30 is mainly performed by the residual tensile stress of the intermediate layer 17. Thereby, the position where the tensile stress reaches a predetermined value (that is, the tip position of the crack 30) and the irradiation position of the laser beam 20 are sufficiently close, and the cutting accuracy is improved. The internal residual tensile stress CT is more preferably 30 MPa or more, and further preferably 40 MPa. When the internal residual tensile stress CT is 30 MPa or more, the crack 30 extends only by the residual tensile stress of the intermediate layer 17, and the tip position of the crack 30 and the irradiation position of the laser beam 20 become closer, so that the cutting accuracy is improved. Further improve.

  As the light source of the laser light 20, for example, a near infrared (hereinafter simply referred to as “near infrared”) laser having a wavelength of 800 to 1100 nm is used. Examples of the near infrared laser include a Yb fiber laser (wavelength: 1000 to 1100 nm), a Yb disk laser (wavelength: 1000 to 1100 nm), an Nd: YAG laser (wavelength: 1064 nm), and a high-power semiconductor laser (wavelength: 808 to 980 nm). ). These near-infrared lasers are high-powered and inexpensive, and it is easy to adjust α × M within a desired range.

  In the present embodiment, a high-power and inexpensive near-infrared laser is used as the light source of the laser light 20, but any light source having a wavelength of 250 to 5000 nm may be used. For example, UV laser (wavelength: 355 nm), green laser (wavelength: 532 nm), Ho: YAG laser (wavelength: 2080 nm), Er: YAG laser (2940 nm), laser using a mid-infrared light parametric oscillator (wavelength: 2600) ˜3450 nm). The oscillation method of the laser beam 20 is not limited, and either a CW laser that continuously oscillates the laser beam or a pulse laser that oscillates the laser beam intermittently 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.

  In the case of a near-infrared laser near 1000 nm (800 to 1100 nm), the absorption coefficient α increases as the iron (Fe) content, cobalt (Co) content, and copper (Cu) content in the tempered glass plate 10 increase. Becomes larger. In this case, the absorption coefficient α increases in the vicinity of the absorption wavelength of the rare earth atom as the content of the rare earth element (for example, Yb) in the tempered glass plate 10 increases. The adjustment of the absorption coefficient α uses iron from the viewpoint of glass transparency and cost, and cobalt, copper, and rare earth elements may not be substantially contained in the tempered glass plate 10.

The intensity of the laser beam 20 is attenuated according to Lambert-Beer's law. Therefore, the front surface 12 and the back surface 14 of the tempered glass plate 10 have the same or substantially the same laser power density (W / cm ² ), that is, the same or substantially the same temperature. The area of the laser beam 20 may be smaller than the area of the laser beam 20 on the surface 12. If the condensing position of the laser beam 20 is on the side opposite to the light source with respect to the tempered glass plate 10, the area of the laser beam 20 on the back surface 14 is smaller than the area of the laser beam 20 on the front surface 12. If the temperatures of the front surface 12 and the back surface 14 of the tempered glass plate 10 are approximately the same, the cracks 30 extend to the same extent on the front surface 12 and the back surface 14 of the tempered glass plate 10.

  In addition, the condensing position of the laser beam 20 may be inside the tempered glass plate 10 or may be on the light source side with reference to the tempered glass plate 10 as shown in FIG.

  On the surface 12 of the tempered glass plate 10, the laser beam 20 may be formed in a circle having a diameter φ smaller than the plate thickness t of the tempered glass plate 10. When the diameter φ is equal to or greater than the plate thickness t, the heated portion of the glass plate 10 is too large, and a part of the cut surface (particularly, the cutting start portion and the cutting end portion) may be slightly curved. The diameter φ is, for example, 1 mm or less, preferably 0.5 mm or less.

  In addition, the shape of the laser beam 20 on the surface 12 of the tempered glass plate 10 may be various, and may be, for example, a rectangle or an ellipse.

  Examples of the usage of the curved plate cut out from the tempered glass plate 10 in the cutting process include vehicle window glass, architectural window glass, curved mirrors for solar thermal power generation, portable devices such as mobile phones and laptop computers. And the like.

  FIG. 14 is a diagram illustrating an example of a cutout position of a curved plate cut out from a tempered glass plate. In FIG. 14, the portion of the curved plate cut out from the tempered glass plate is indicated by oblique lines.

  In the cutting step, the curved plates 101, 102, and 103 can be cut out from a portion of the tempered glass plate 10 that is free from problems such as unintended warping and insufficient bending. Therefore, a curved plate having a desired shape can be obtained.

  For example, in FIG. 14A, the curved plate 101 having a desired shape is obtained by cutting off the end of the tempered glass plate 10 as a portion having a problem such as unintentional warping or insufficient bending.

  Moreover, in FIG.14 (b), the curved plate 102 of the shape requested | required is obtained by excising the outer peripheral part of the tempered glass board 10 as a faulty part. In the case of air cooling strengthening, since the outer peripheral portion of the tempered glass plate 10 is supported by a ring, a portion with a support trace of the tempered glass plate 10 can be cut out as a defective portion.

  Furthermore, in FIG. 14 (c), as shown in FIG. 6, a curved plate having a shape that is insufficiently bent when bent after cutting can be formed into a desired shape by cutting after bending. In this case, the tempered glass plate 10 may not be defective. Similarly, even a shape having a through hole as shown in FIG. 5 can be formed into a desired shape.

  FIG. 15 is a diagram illustrating another example of the cutout position of the curved plate cut out from the tempered glass plate. In FIG. 15, the portion of the curved plate cut out from the tempered glass plate is indicated by hatching.

  In the cutting step, a plurality of curved plates 104 and 105 may be cut out from one tempered glass plate 10. The plurality of curved plates 104 and 105 cut out from one tempered glass plate 10 are a plurality of window glasses on a design surface (for example, a side surface of a vehicle, a top surface of a vehicle, or a curved surface of a building) on which a plurality of window glasses are formed. It may be a shape corresponding to each. For example, the plurality of curved plates 104 and 105 are a window glass attached to the front side of the left side surface of a certain type of vehicle and a window glass attached to the rear side of the left side surface of the same type of vehicle. In that case, in the molding step of bending the glass plate, the glass plate is bent so as to have at least the same curved surface as a continuous region where a plurality of window glasses on the design surface are formed. For example, if it is the side surface of a vehicle, a glass plate is shape | molded so that it may become the same curved surface as the curved surface of the continuous area | region including the area | region between the window glass of a front side, a rear side window glass, and each window glass. Then, through the tempering step, the plurality of curved plates are cut out from the positions of the tempered glass plates corresponding to the positions where the plurality of window glasses on the design surface are formed in the cutting step. For example, in the case of the side surface of the vehicle, it corresponds to the position where the front window glass is actually formed and the position where the rear window glass is formed from the tempered glass plate 10 formed on the same curved surface as the vehicle side surface. Cut out each window glass from the position to be. Not only a plurality of window glasses but also a glass plate is formed on a design surface including a region other than a plurality of window glasses, and each window glass is cut out from the corresponding position. The surface looks beautiful.

  Furthermore, it is preferable that a plurality of curved plates 104 and 105 cut out from one tempered glass plate 10 is used as a plurality of window glasses that form a design surface of the same object. For example, the plurality of curved plates 104 and 105 are a window glass attached to the front side of the left side surface of one vehicle and a window glass attached to the rear side of the left side surface of the same vehicle. Since a plurality of window glasses forming the same design surface are cut out from one tempered glass plate 10, the continuity of the plurality of window glasses is better and the appearance of the design surface is beautiful.

  The plurality of curved plates 104 and 105 cut out from one tempered glass plate 10 may be window glass attached to the same design surface of another object. For example, the plurality of curved plates 104 and 105 are a window glass attached to the front side of the left side surface of one vehicle and a window glass attached to the rear side of the left side surface of another vehicle of the same shape. The continuity of the plurality of window glasses is better than when a single window glass is cut out from one tempered glass plate 10, and the appearance of the design surface is beautiful.

  The plurality of curved plates 104 and 105 cut out from one tempered glass plate 10 may be attached to different parts of the design surface, and may have different shapes or the same shape as shown in FIG.

  FIG. 16 is a diagram illustrating a protection process according to the first embodiment of the present invention.

  The method for manufacturing the curved plate may further include a step of protecting the cut surface of the cut curved plate (for example, the curved plate 101 in FIG. 16) with the resin 19. Instead of chamfering the cut surface of the curved plate, the curved plate is difficult to break. As the resin 19, for example, a thermoplastic elastomer (for example, polyvinyl chloride) is used.

  The resin 19 may be formed only on the cut surface of the curved plate as shown in FIG. 16A, or may be formed so as to protrude from the cut surface of the curved plate as shown in FIG.

[Second Embodiment]
FIG. 17 is an explanatory diagram of a cutting process according to the second embodiment of the present invention. In FIG. 17, the same components as those in FIG.

  The cutting step of the present embodiment includes a step of locally blowing the gas 40 to the tempered glass plate 10, and moving the spray position of the gas 40 on the tempered glass plate 10 in conjunction with the irradiation position of the laser light 20. The tempered glass plate 10 is cut. As shown in FIG. 17, the irradiation position of the laser beam 20 may exist inside the spray position of the gas 40. Note that the spray position of the gas 40 may be in front of or behind the irradiation position of the laser beam 20. The gas 40 blows off a deposit (for example, dust) on the tempered glass plate 10 to prevent the laser light 20 from being absorbed by the deposit and prevent the surface 12 of the tempered glass plate 10 from being overheated.

  The gas 40 may be a cooling gas (for example, compressed air at room temperature) that locally cools the tempered glass plate 10. Since a rapid temperature gradient occurs along the moving direction of the irradiation position of the laser beam 20, the distance between the position where the tensile stress reaches a predetermined value (that is, the tip position of the crack 30) and the position of the laser beam 20 is Shorter. Therefore, since the position controllability of the crack 30 is improved, the cutting accuracy can be further improved.

  The nozzle 50 is formed in a cylindrical shape as shown in FIG. 17, for example, and the laser beam 20 may pass through the nozzle 50. The central axis 51 of the nozzle 50 and the optical axis 21 of the laser light 20 may be arranged coaxially. The positional relationship between the spray position of the gas 40 and the irradiation position of the laser beam 20 is stabilized.

  The tempered glass plate 10 may move, the nozzle 50 may move, or both may move for the movement of the blowing position of the gas 40 in the tempered glass plate 10.

  The first and second embodiments of the method for cutting a curved plate have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications and replacements are possible within the scope described in the claims. is there.

DESCRIPTION OF SYMBOLS 10 Tempered glass plate 12 Front surface 13 Front surface layer 14 Back surface 15 Back surface layer 17 Intermediate layer 20 Laser beam 30 Crack 40 Gas

Claims (10)

A molding process for bending a glass sheet softened by heating;
Front and back layers as reinforcing layers having a residual compressive stress by reinforcing the front and back surfaces of the bent glass plate, and an intermediate layer having an internal residual tensile stress formed between the front and back layers A tempering step for producing a tempered glass plate comprising:
Irradiate laser beam locally on the tempered glass plate, move the irradiation position of the laser beam on the tempered glass plate, extend cracks penetrating the tempered glass plate in the plate thickness direction, and curve from the tempered glass plate A cutting step of cutting a plate,
In the cutting step, the intermediate layer is locally heated by the laser light at a temperature below the annealing point, and a tensile stress or a compressive stress smaller than the internal residual tensile stress is locally generated in the intermediate layer. A method for manufacturing a curved plate, wherein the extension rate of cracks due to the internal residual tensile stress is controlled.   The said cutting process is a manufacturing method of the curved plate of Claim 1 which cuts out a several curved plate from one said tempered glass plate. The plurality of curved plates cut out from one of the tempered glass plates has a shape corresponding to each of the plurality of window glasses on a design surface on which a plurality of window glasses are formed,
In the forming step, the glass plate is bent and formed so as to have the same curved surface as a continuous region where a plurality of window glasses on the design surface are formed,
The method for producing a bent tempered glass plate according to claim 2, wherein the cutting step cuts the plurality of curved plates from positions of the tempered glass plate corresponding to positions where the plurality of window glasses on the design surface are formed. .   The method of manufacturing a curved plate according to claim 2, wherein the plurality of curved plates are a plurality of window glasses that form the design surface of the same object.   The manufacturing method of the curved plate as described in any one of Claims 1-4 which further has a protection process which protects the cut surface of the said curved plate with resin.   The manufacturing method of the curved plate as described in any one of Claims 1-5 whose wavelength of the said laser beam is 250-5000 nm.   The manufacturing method of the curved plate as described in any one of Claims 1-6 whose internal residual tensile stress of the said intermediate | middle layer is 15 Mpa or more.   The manufacturing method of the curved plate of Claim 7 whose internal residual tensile stress of the said intermediate | middle layer is 30 Mpa or more.   The said cutting process includes the process of spraying gas locally on the said tempered glass board, and moves the spraying position of the gas in the said tempered glass board in conjunction with the irradiation position of the said laser beam. The manufacturing method of the curved board as described in any one.   The method for manufacturing a curved plate according to claim 9, wherein the gas is a cooling gas for cooling the tempered glass plate heated by the laser beam.

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