TW201329006A - Method for cutting toughened glass plates and device for cutting toughened glass plates - Google Patents

Abstract

In a method for cutting toughened glass plates in one embodiment of the present invention, a toughened glass plate (10) provided with a front layer and a back layer that have residual compressive stresses and a middle layer that is formed between said front and back layers and has internal residual tensile stress is cut by moving a laser-light exposure region. When doing so, the amount of laser-light energy to which the toughened glass plate is exposed per unit area is increased for a section extending from before a crack-initiation location (43) to a cutting endpoint (42). The present invention makes it possible to cut a toughened glass plate using laser light without degrading the quality of the glass plate.

Description

Method for cutting tempered glass sheet and tempered glass sheet cutting device

The present invention relates to a method for cutting a tempered glass sheet and a tempered glass sheet cutting device.

In recent years, in mobile devices such as mobile phones and PDAs (Personal Digital Assistants), in order to improve the protection or aesthetics of the display (including the touch panel), the use of cover glass (protective glass) has increased. Further, as a substrate of a display, a glass substrate is widely used.

On the other hand, the thinning and weight reduction of the mobile equipment are promoted, and the thinning of the glass used in the mobile equipment is promoted. When the glass is thinned, the strength is lowered. Therefore, in order to compensate for the insufficient strength of the glass, a tempered glass including a front layer and a back layer of residual compressive stress is developed. Tempered glass is also used as window glass for automobiles or window glass for construction.

The tempered glass is produced by, for example, air-cooling strengthening method or chemical strengthening method. In the air-cooling strengthening method, the glass having a temperature around the softening point is rapidly cooled from the front and the back, and a temperature difference is generated between the front surface and the back surface of the glass and the inside, thereby forming a front layer and a back layer of residual compressive stress. On the other hand, the chemical strengthening method performs ion exchange on the front and back sides of the glass, and replaces ions of a smaller ionic radius (for example, Li ions, Na ions) contained in the glass with ions having a larger ionic radius (for example, K ion), thereby forming a front layer and a back layer of residual compressive stress. In either method, as a reaction, an intermediate layer of residual tensile stress is formed between the front layer and the back layer.

In the case of manufacturing tempered glass, the glass size of the product is compared to the block by piece. The glazing is reinforced, and it is more efficient to cut and multi-chamfer the glass after strengthening the glass larger than the larger size of the product. Therefore, as a method of cutting the tempered glass sheet, there is proposed a method of irradiating the front surface of the tempered glass sheet with laser light and moving the irradiation region of the laser light on the front surface of the tempered glass sheet, thereby cutting the tempered glass sheet (refer to Patent Document 1 and Patent Document 2).

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-247732

Patent Document 2: International Publication No. 2010/126977

When the non-reinforced glass is cut by laser light, the crack is stretched using thermal stress generated by irradiation of laser light. On the other hand, when the tempered glass sheet is cut by laser light, the compressive stress generated in the region irradiated with the laser light (or the tensile stress lower than the residual tensile stress) is used to control the residual stretch existing in the intermediate layer. The extension of the crack caused by the stress is cut off. Therefore, it is necessary to appropriately control the stretching of the crack while suppressing the crack from being stretched in the unexpected direction. When the crack is stretched in the unexpected direction, there is a problem that the cut line is separated from the line to cut, and the quality of the tempered glass sheet after cutting is deteriorated.

In view of the above problems, an object of the present invention is to provide a method for cutting a tempered glass sheet and a tempered glass sheet cutting device which use a laser beam to cut a tempered glass sheet without deteriorating the quality.

A method of cutting a tempered glass sheet according to a first aspect of the present invention is directed to a front layer and a back layer including residual compressive stress and formed between the front layer and the back layer and having an internal residual tensile stress CT (MPa) The tempered glass sheet of the intermediate layer is cut by moving the irradiation region of the laser light irradiated on the tempered glass sheet, and the thickness of the front layer and the back layer is set to DOL (μm), and the reinforcement is performed. The thickness of the glass plate is t ₁ (μm), and when the Young's modulus of the tempered glass plate is Y (MPa), the strain energy per unit area based on the internal residual tensile stress CT expressed by the following formula is expressed by the following formula U _CT (J/m ² ) is set to 2.5 J/m ² or more, and the tempered glass sheet is cut at a cutting end point on the side surface of the tempered glass sheet so as to be acutely angled with respect to the side surface. The irradiation end energy of the laser light per unit irradiation area of the tempered glass sheet is greater than a linear shape in a section from the specific end position of the tempered glass sheet to the predetermined position before the cutting end point. The irradiation energy of the laser light per unit irradiation area required for cutting the above tempered glass sheet. U _CT = {CT ² × (t ₁ - 2 × DOL)} / (2 × Y).

A method of cutting a tempered glass sheet according to a second aspect of the present invention is the method for cutting a tempered glass sheet, wherein an effective output of the laser light incident on the tempered glass sheet is Pe (W), The scanning speed of the laser light is set to v (mm/s), the absorption coefficient of the tempered glass sheet with respect to the laser light is α (mm ^-1 ), and the thickness of the tempered glass sheet is t ₂ (mm). The linear expansion coefficient of the tempered glass sheet is α _L (K ^-1 ), the density of the tempered glass sheet is ρ (g/mm ³ ), and the specific heat of the tempered glass sheet is c (J). In the case of /g/K), the cutting index K (N/mm) expressed by the following formula is set to 150 N/mm or less. K = Pe / v × exp (-α × t ₂ ) × (Y × α _L ) / (t ₂ × ρ × c).

A method for cutting a tempered glass sheet according to a third aspect of the present invention is the method for cutting a tempered glass sheet, wherein the tempered glass sheet and the laser light system set an absorption coefficient of the tempered glass sheet with respect to the laser light. when α (mm ^-1), the thickness of the tempered glass sheet to t ₂ (mm), satisfying 0 <α × t ₂ ≦ 3.0 the formula.

A method of cutting a tempered glass sheet according to a fourth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the specific position at a predetermined distance from the end of the cutting end is located toward a side of the tempered glass sheet. The crack of the unexpected crack is generated in the same position.

A method of cutting a tempered glass sheet according to a fifth aspect of the present invention is the method for cutting a tempered glass sheet, wherein a line segment connecting the scanning position of the laser light to the cutting end point and a side surface of the tempered glass sheet The smaller the angle formed, the larger the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet.

A method of cutting a tempered glass sheet according to a sixth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the unit per unit area is irradiated by slowing a moving speed of the irradiation region of the laser light. The irradiation energy of the laser light becomes large.

A method of cutting a tempered glass sheet according to a seventh aspect of the present invention is the method for cutting a tempered glass sheet, wherein the irradiation of the laser light per unit irradiation area is performed by increasing the output of the laser light. The energy is getting bigger.

A method of cutting a tempered glass sheet according to an eighth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the radiant per unit irradiation area is made smaller by reducing an area of the irradiation area of the laser light. The irradiation energy of the light is increased.

A method of cutting a tempered glass sheet according to a ninth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the laser light per unit irradiation area is increased as the absorption coefficient α of the tempered glass sheet becomes larger The irradiation energy becomes smaller.

A method for cutting a tempered glass sheet according to a tenth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the laser light per unit irradiation area is increased as the thermal expansion coefficient of the tempered glass sheet becomes larger The irradiation energy becomes small.

The method for cutting a tempered glass sheet according to the eleventh aspect of the present invention is the method for cutting a tempered glass sheet, wherein the irradiation of the laser light per unit irradiation area is performed as the thickness of the tempered glass sheet becomes thicker. The energy is getting bigger.

A method of cutting a tempered glass sheet according to a twelfth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the periphery of the irradiation region of the laser light is further cooled.

A method for cutting a tempered glass sheet according to a thirteenth aspect of the present invention is the method for cutting a tempered glass sheet, wherein the irradiation region of the laser light is applied to at least one of a front surface and a back surface of the tempered glass sheet Cooled around.

A method of cutting a tempered glass sheet according to a fourteenth aspect of the present invention is the method for cutting a tempered glass sheet, wherein a periphery of an irradiation region of the laser light is cooled by ejecting a gas from a nozzle.

A tempered glass sheet cutting device according to a fifteenth aspect of the present invention is directed to a reinforcing layer comprising a front layer and a back layer having residual compressive stress and an intermediate layer formed between the front layer and the back layer and having internal residual tensile stress The glass plate is cut by moving an irradiation region of the laser light irradiated to the tempered glass sheet, and includes: a glass holding driving portion that holds the tempered glass sheet and moves the tempered glass sheet in a specific direction; a radiation output unit that outputs laser light for cutting the tempered glass sheet; a control unit that controls the glass holding drive unit and the laser output unit based on a control program; and a control program generation unit that generates the control program; The control program generation unit generates a control program for cutting the tempered glass sheet from a distance from the tempered glass sheet when the tempered glass sheet is cut toward the end of the cutting at the side surface of the tempered glass sheet at an acute angle with respect to the side surface Cutting the end point at a specific distance from the specific position up to the end point of the cutting end, and irradiating the above The laser beam irradiated per unit area of the irradiation energy is greater than the glass plate was irradiated with an energy per unit area of laser light irradiation of the time required for cutting the linearly strengthened glass sheet.

According to the present invention, it is possible to provide a method for cutting a tempered glass sheet and a tempered glass sheet cutting device which use a laser beam to cut the tempered glass sheet without deteriorating the quality.

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 embodiments. Further, in order to clarify the description, the following description and drawings are appropriately simplified.

<Overview of the structure and cutting method of the tempered glass sheet>

First, an outline of a structure of a tempered glass sheet and a method of cutting a tempered glass sheet will be described with reference to Figs. 1 to 5 .

First, the structure of the tempered glass sheet will be described with reference to Figs. Figure 1 is a cross-sectional view of a strengthened glass sheet 10 prior to exposure to 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 sheet 10 includes a front layer 13 and a back layer 15, and an intermediate layer 17 disposed between the front layer 13 and the back layer 15. The front layer 13 and the back layer 15 are subjected to compressive stress 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 sheet 10 is produced by, for example, an air cooling strengthening method or a chemical strengthening method. The type of glass used for reinforcement is selected according to the use. For example, in the case of a window glass for a car, a window glass for a building, a glass substrate for a PDP (Plasma Display Panel), or a cover glass, an alkali aluminosilicate glass or sodium is used as a glass for reinforcement. Calcium glass.

In the air-cooling strengthening method, the glass having a temperature around the softening point is rapidly cooled from the front and the back, and a temperature difference is generated between the front surface and the back surface of the glass and the inside, thereby forming a front layer and a back layer of residual compressive stress. The air-cooled strengthening method is suitable for strengthening thicker glass.

The chemical strengthening method ion-exchanges the front and back sides of the glass, and replaces ions of a smaller ionic radius (such as Li ions and Na ions) contained in the glass with ions of a larger ionic radius (for example, K ions). Thereby, the front layer and the back layer of residual compressive stress are formed. Chemical strengthening method is suitable for alkali aluminum Indole glass or soda lime glass fortification.

Fig. 2 is a schematic view showing the distribution of residual stress of the strengthened glass sheet before the irradiation of the laser light.

As shown in FIG. 2, the compressive stress (>0) remaining in the front layer 13 and the back layer 15 tends to gradually decrease toward the inside from the front surface 12 and the back surface 14 of the tempered glass sheet 10. 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.

In Fig. 2, CS indicates the maximum residual compressive stress (surface compressive stress) (>0) in the front layer 13 or the back layer 15, and CT indicates the internal residual tensile stress in the intermediate layer 17 (residual tensile of the intermediate layer 17) The average value of the stress (>0), DOL indicates the thickness of the front layer 13 and the back layer 15, and t indicates the thickness of the tempered glass sheet 10. Therefore, the thickness of the intermediate layer 17 becomes t-2 × DOL.

Further, the internal residual tensile stress CT (MPa) of the tempered glass sheet is generally measured for the surface compressive stress CS (MPa) and the thickness DOL (μm) of the front layer 13 and the back layer 15, and the measured value and the tempered glass sheet are used. The thickness t ₁ (μm) was calculated using the following formula 1.

CT=(CS×DOL)/(t ₁ -2×DOL)...Form 1

Further, the strain energy per unit area of the internal residual tensile stress CT (hereinafter, simply referred to as "internal strain energy") U _CT (J/m ² ) can be determined by using the Young's modulus Y (MPa) of the tempered glass sheet. It is obtained by the following formula 2.

U _CT ={CT ² ×(t ₁ -2×DOL)}/(2×Y)...Form 2

The inventors investigated the minimum value (hereinafter referred to as critical irradiation energy) Ec of the irradiation energy E of the laser light required for cutting the tempered glass sheet having various internal strain energies U _CT . As a result, it has been found that when the internal strain energy U _CT <2.5 J/m ^{2 of the} tempered glass sheet is used, the critical irradiation energy Ec is rapidly increased (specifically, several times) even if the cutting conditions are the same. And the cutting accuracy is also deteriorated. At the same time, the inventors have found that if the internal strain energy U _CT ≧2.5 J/m ² of the tempered glass sheet is used, the critical irradiation energy Ec is substantially fixed as long as the material, thickness and laser wavelength of the tempered glass sheet are the same. The value and cutting accuracy are also improved. That is, the inventors have found that when the tempered glass sheet is cut, by setting the internal strain energy U _CT ≧2.5 J/m ² , the crack extension due to the internal residual tensile stress predominates, and The smaller irradiation energy is cut off with high precision.

That is, it is considered that the switching of the cut mode occurs in the vicinity of the internal strain energy U _CT = 2.5 J/m ² . Specifically, as the crack extension energy for cutting the tempered glass sheet, in the case of the internal strain energy U _CT <2.5 J/m ² , in addition to the internal strain energy, the irradiation energy of the laser light is required, and the internal strain is required. When the energy U _CT ≧ 2.5 J/m ² , it only becomes the internal strain energy. Further, in the case of U _CT ≧ 2.5 J/m ² , it is not intended to cause the crack to progress, but conversely, in order to suppress and control the stretching of the crack, the irradiation energy of the laser light is required.

Here, the maximum residual compressive stress CS or the internal residual tensile stress CT, the thickness of the front layer 13 and the back layer 15 DOL can be adjusted by the tempering treatment conditions. For example, when the maximum residual compressive stress CS or the internal residual tensile stress CT, and the thickness DOL of the front layer 13 and the back layer 15 are in the case of the air-cooling strengthening method, the cooling rate of the glass or the like can be adjusted. Further, when the maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the front layer 13 and the back surface layer 15 are in the case of the chemical strengthening method, the glass is immersed in the treatment liquid (for example, KNO ₃ molten salt). Since ion exchange is performed, it can be adjusted by the concentration or temperature of the treatment liquid, the immersion time, and the like. Further, the front layer 13 and the back layer 15 of the present embodiment have the same thickness DOL and maximum residual compressive stress CS, but may have different thicknesses or maximum residual compressive stresses.

Fig. 3 is a view for explaining a cutting method of a tempered glass sheet. As shown in FIG. 3, the front surface 12 of the tempered glass sheet 10 is irradiated with the laser light 20, and the irradiation region 22 of the laser light 20 is moved (scanned) on the front surface 12 of the tempered glass sheet 10, thereby applying stress to the tempered glass sheet 10. And the tempered glass sheet 10 is cut.

At the end portion of the tempered glass sheet 10, initial cracks are formed in advance at the cutting start position. The method of forming the initial crack may be a general method, and it may be formed by, for example, a cutter, a file, or a laser. Further, for the internal heating cutting using the laser light, it is not necessary to form a scribe line (groove line) along the line to cut along the front surface 12 of the tempered glass sheet 10.

On the front surface 12 of the tempered glass sheet 10, the irradiation region 22 of the laser light 20 is moved linearly or in a curved shape along the line to cut from the end portion of the tempered glass sheet 10 toward the inside. Thereby, the crack 30 is extended from the end of the tempered glass sheet 10 toward the inside, and the tempered glass sheet 10 is cut.

In order to move the irradiation region 22 of the laser light 20 on the front surface 12 of the tempered glass sheet 10, the holder supporting the tempered glass sheet 10 can be moved or rotated, and the light source of the laser light 20 can be moved. Further, the mirror provided in the middle of the path of the laser light 20 can be rotated.

On the front side 12 of the tempered glass sheet 10, the irradiated area 22 of the laser light 20 is the thickness or maximum residual compressive stress CS of the strengthened glass sheet 10, the internal residual tensile stress CT, the thickness of the front layer 13 or the back layer 15 DOL. ,laser The output of the light source of 20 moves at a corresponding speed.

The light source of the laser light 20 is not particularly limited, and examples thereof include UV (ultraviolet) laser (wavelength: 355 nm), green laser (wavelength: 532 nm), and semiconductor laser (wavelength: 808 nm, 940). Nm, 975 nm), fiber laser (wavelength: 1060~1100 nm), YAG (Yttrium Aluminum Garnet) laser (wavelength: 1064 nm, 2080 nm, 2940 nm), oscillating with mid-infrared light parameters Laser (wavelength: 2600 ~ 3450 nm) and so on. The oscillation mode of the laser light 20 is not limited, and any of a CW (Continuous Wave) laser that continuously oscillates laser light and a pulsed laser that intermittently oscillates the laser light can be used. Further, the intensity distribution of the laser light 20 is not limited, and may be either a Gaussian type or a top hat type.

The laser light 20 emitted from the light source is collected by a collecting lens or the like and imaged on the front surface 12 of the tempered glass sheet 10. When the condensing position of the laser light 20 is based on the front surface 12 of the tempered glass sheet 10, it may be either the laser light source side or the back surface 14 side. Further, if the condensing area below the freezing point is maintained so that the heating temperature is not excessively high, the condensing position of the laser light 20 may be in the tempered glass sheet 10.

The optical axis of the laser light 20 is attached to the front side 12 of the tempered glass sheet 10. For example, as shown in FIG. 3, it may be orthogonal to the front surface 12 or may be oblique to the front surface 12.

The absorption coefficient of the strengthened glass plate 10 with respect to the laser light 20 is set to α (mm ^-1 ), the thickness of the strengthened glass plate 10 is set to t ₂ (mm), and the strengthened glass plate 10 and the laser light 20 satisfy 0 < α × t ₂ when the formula of 3.0 ≦ case, the only action by a laser light 20, the intermediate layer 17 can take advantage of a tensile residual tensile stress induced cracking of the strengthened glass sheet 10 is cut. That is, under the above conditions, the intermediate layer 17 in the irradiation region 22 of the laser light 20 is heated at a temperature lower than the freezing point, whereby the crack generated in the tempered glass sheet 10 can be controlled by the residual tensile stress of the intermediate layer 17 The stretching is performed, and the tempered glass sheet 10 is cut by the crack 30 caused by the residual tensile stress. In addition, the reason why the intermediate layer 17 is heated at a temperature lower than the cold point is that if the heating is performed beyond the cold spot, the glass becomes high in a short period of time during which the laser light passes, and the viscous flow is likely to occur. Therefore, the compressive stress generated by the laser light due to the viscous flow is alleviated. Further, the value t ₂ (mm) of the thickness (plate thickness) t of the tempered glass sheet 10 is different from the value t ₁ (μm) in the formulas 1 and 2.

If the laser is incident to strengthen the glass plate 10 before the intensity of the light 20 is set to I _0, it will increase the strength of the glass sheet 10 moves only the laser when the distance L (mm) of the light 20 is set to I, according to the Lambert - The law of Beer's law is established as follows.

I=I ₀ ×exp(-α×L)

By setting α × t ₂ to be larger than 0 and 3.0 or less, the laser light 20 is absorbed to the front surface of the tempered glass sheet 10 and reaches the inside, so that the inside of the tempered glass sheet 10 can be sufficiently heated. As a result, the stress generated in the tempered glass sheet 10 changes from the state shown in Fig. 1 to the state shown in Fig. 4 or Fig. 5.

Figure 4 is a cross-sectional view taken along line A-A of Figure 3, which is a cross-sectional view of an irradiation area including laser light. Fig. 5 is a cross-sectional view taken along line B-B of Fig. 3, and is a cross section taken along the line of Fig. 4; Here, the term "rear" refers to the rear of the scanning direction of the laser light 20. In FIGS. 4 and 5, the direction of the arrow indicates the direction in which the stress acts, and the length of the arrow indicates the magnitude of the stress.

In the intermediate layer 17 in the illumination area 22 of the laser light 20, due to the laser light The strength of 20 is very high, so the temperature is higher than the periphery, resulting in tensile stress or compressive stress which is smaller than the residual tensile stress shown in Figs. 1 and 2. The extension of the crack 30 is suppressed in the portion where the tensile stress or the compressive stress which is smaller than the residual tensile stress is generated. In order to surely prevent the extension of the crack 30, it is preferable to generate a compressive stress as shown in FIG.

Furthermore, as shown in FIG. 4, in the front layer 13 or the back layer 15 in the irradiation region 22 of the laser light 20, a compressive stress larger than the residual compressive stress shown in FIGS. 1 and 2 is generated, so that the crack 30 Stretching is suppressed.

In order to balance with the compressive stress shown in FIG. 4, the cross section behind the cross section shown in FIG. 4, as shown in FIG. 5, generates tensile stress in the intermediate layer 17. The tensile stress is greater than the residual tensile stress, and the crack 30 is formed in a portion where the tensile stress reaches a specific value. The crack 30 is formed from the front surface 12 of the tempered glass sheet 10 to the back surface 14, and the cutting shown in Fig. 3 is a so-called full cut type.

In this state, when the irradiation region 22 of the laser light 20 is moved, the position of the front end of the crack 30 moves 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 sheet 10 is cut, the stretching direction of the crack 30 is controlled by the tensile stress generated in the scanning direction of the laser light (see FIG. 5), and the irradiation is used. The compressive stress generated in the region having the laser light (see Fig. 4) is cut while suppressing the extension of the crack 30. That is, the stretching of the crack 30 is controlled using the compressive stress generated by the irradiation of the laser light 20. As a result, it is possible to suppress the crack 30 from being freely diffused from the line to cut.

The glass requires a high transparency depending on the use. Therefore, when the wavelength of the laser is close to the wavelength region of visible light, the closer α × t ₂ is to 0, the better. However, if α × t _{2 is} too small, the absorption efficiency is deteriorated. Therefore, it is preferably 0.0005 or more (the laser light absorption rate is 0.05% or more), more preferably 0.002 or more (the laser light absorption rate is 0.2% or more), and further preferably. It is 0.004 or more (the laser light absorption rate is 0.4% or more).

Since glass requires a lower transparency depending on the application, when the wavelength of the laser is close to the wavelength region of visible light, the larger α × t ₂ is, the better. However, if α × t _{2 is} too large, the surface absorption of the laser light becomes large, and the crack extension cannot be controlled. Therefore, α × t _{2 is} preferably 3.0 or less (the laser light absorption rate is 95% or less), more preferably 0.1 or less (the laser light absorption rate is 10% or less), further preferably 0.02 or less (the laser light absorption rate is 2% or less). ).

The thickness t ₂ (mm) of the tempered glass sheet 10 is set depending on the application, and 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, if the thickness t ₂ (mm) is less than 0.1 mm, it is difficult to perform chemical strengthening treatment on the glass. The thickness t ₂ (mm) is more preferably 0.3 to 1.5 mm, and further preferably 0.5 to 1.5 mm.

The absorption coefficient α is defined by the wavelength of the laser light 20, the glass composition of the tempered glass sheet 10, and the like.

For example, the absorption coefficient α in the near-infrared wavelength region of about 1000 nm is the content of iron oxide (including FeO, Fe ₂ O ₃ , Fe ₃ O ₄ ) in the strengthened glass plate 10, and cobalt oxide (including CoO, Co ₂ O _{3 ).} The content of Co ₃ O ₄ ) and the content of copper oxide (including CuO and Cu ₂ O) increase 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 the iron oxide in the tempered glass sheet 10 depends on the type of the glass constituting the tempered glass sheet 10, and is, for example, 0.02 to 1.0% by mass in the case of soda lime glass. However, the more the content of iron oxide or the like, the lower the transparency of the visible light region of the tempered glass sheet 10.

The absorption coefficient (α) in the near-infrared wavelength region of about 1000 nm is set according to the use. For example, in the case of a window glass for automobiles, the absorption coefficient (α) is preferably 0.3 mm ^-1 or less. Further, in the case of a glazing for construction, the absorption coefficient (α) is preferably 0.06 mm ^-1 or less. Further, in the case of glass for a display, the absorption coefficient (α) is preferably 0.02 mm ^-1 or less.

Further, the absorption coefficient α in the vicinity of the absorption wavelength of the rare earth atom increases as the content of the oxide of the rare earth element (for example, Yb) in the tempered glass sheet 10 increases.

Further, the absorption coefficient α in the mid-infrared wavelength region of about 3000 nm is larger as the content of the OH group in the tempered glass sheet 10 increases. Here, the content of the OH group does not affect the transparency of the visible light region.

The wavelength of the laser light 20 may be 250 to 5000 nm, preferably 2500 to 3500 nm. In the case where the wavelength of the laser light 20 is 2500 to 3500 nm (about 3000 nm), as described above, the absorption coefficient α can be increased without lowering the transparency of the visible light region. As a result, the heating efficiency of the laser light 20 can be improved. The wavelength of the laser light 20 is further preferably set to 2700 to 3200 nm.

For example, when the wavelength of the laser light is about 1000 nm, the absorption rate of the tempered glass sheet having an iron oxide content of 0.04% by mass is about 2% when the thickness t ₂ (mm) is 1 mm (transmission ratio). : About 98%). Therefore, the heating efficiency of the irradiation of the laser light is inferior. Further, since the absorption rate changes depending on the Fe concentration, it is necessary to largely change the irradiation conditions of the laser light in accordance with the composition of the tempered glass sheet.

On the other hand, for example, when the wavelength of the laser light is about 3000 nm, the absorption rate of the tempered glass sheet is about 50% regardless of the content of the iron oxide, and is about 50% (transmission ratio). : About 50%). Therefore, the heating efficiency is improved as compared with the case where the wavelength is about 1000 nm, and it is not necessary to largely change the irradiation conditions of the laser light depending on the composition of the tempered glass sheet.

Further, when the wavelength is about 1000 nm and the absorption rate is about 2%, for example, if the absorption power of 2 W is required for the cutting, 100 W is applied and 98 W is transmitted. Therefore, if the platen is placed under the cutting line through which the laser light passes, the platen is damaged by the laser light. Therefore, it is necessary to design a small lap of the tempered glass panel which is cut out from the tempered glass sheet. Also, it is necessary to process the transmitted laser light. Further, since the transmittance is high, there is a case where the reflected light in the end surface of the tempered glass sheet adversely affects. Further, when the absorption rate of the laser light is increased by the foreign matter attached to the front or the back surface, the change in the absorption amount is large, and the adverse effect is caused. Further, when the absorption rate changes by only 1% from 2% to 1% due to the Fe concentration, it is necessary to change the input power from 100 W to 200 W to 100 W.

On the other hand, when the wavelength is about 3000 nm and the absorption rate is about 50%, if the absorption power of 2 W is required for the cutting, 4 W is applied and 2 W is transmitted. Thus, compared with the case where the wavelength is about 1000 nm, the input power can be drastically reduced, and the heating efficiency can be improved. In addition, the transmitted light is also drastically reduced, so that the platen is not damaged even if the platen is placed under the line of cut through which the laser light passes. Therefore, by placing the strengthened glass on the cut The platen of the tempered glass plate can be cut off in a more stable state. Moreover, there is no need to process the transmitted laser light. Further, the power of the reflected light in the end surface of the tempered glass sheet is also small, and it is not easy to cause adverse effects. Further, even if the absorption rate of the laser light is increased by the foreign matter attached to the front or the back surface, the change in the absorption amount is small, and it is not easy to cause an adverse effect. Further, the absorption rate is not changed by the Fe concentration, and when the absorption rate is reduced by 10% from 50% to 40%, the input power can be changed from 4 W to 5 W by only 1 W. .

The tempered glass sheet can be cut by using the method described above.

<Detailed description of the method of cutting the tempered glass sheet>

Next, the method of cutting the tempered glass sheet of the present embodiment will be described in detail.

In the above description, the wavelength of the laser light is preferably about 3,000 nm. However, the method for cutting the tempered glass sheet described below is not limited to this wavelength. For example, the wavelength can be widely used. ~5000 nm laser light.

Fig. 6 is a view for explaining a cutting method of the tempered glass sheet of the embodiment. Fig. 6 is a view obtained by observing the tempered glass sheet 10 from above. Further, a broken line 48 shown by the tempered glass sheet 10 indicates a line to cut when the sample 40 is cut out from the tempered glass sheet 10 by the cutting method described above. The sample 40 includes a quadrangle having four corner portions and a straight portion having a specific radius of curvature. Further, the sample 40 shown in FIG. 6 is an example. When a sample having another arbitrary shape is cut out from the tempered glass sheet 10, the method of cutting the tempered glass sheet of the present embodiment may be used.

When the sample 40 is cut out from the tempered glass sheet 10, the laser light is scanned in such a manner as to pass through the cut line 48. That is, scanning of the laser light is started from the cutting start point 41, and the laser beam is scanned along the line to cut 48 in the direction of the arrow shown in FIG. 6, and the scanning of the laser beam is completed at the cutting end point 42. At this time, initial cracks are formed in advance at the end portion of the tempered glass sheet 10 at the cutting start point 41. The initial crack can be formed by, for example, a cutter, a file, or a laser.

As described above, when the tempered glass sheet is cut by laser light, it is necessary to optimize the conditions of the laser light irradiated to the tempered glass sheet. In other words, when the conditions of the laser light irradiated to the tempered glass sheet are not appropriate, there is a problem that the crack propagates in an unexpected direction, and the cutting line is separated from the line to cut, and the quality of the tempered glass sheet after cutting is deteriorated.

Fig. 7A is a view showing an example of a state in which the tempered glass sheet is cut in a case where the conditions of the laser light irradiated to the tempered glass sheet are inappropriate, and is an enlarged view of the vicinity of the cutting end point 42 shown in Fig. 6 . As shown in FIG. 7A, when the condition of the laser light is inappropriate, when the laser light is scanned along the line to cut 48, the unexpected crack 46 extends from the crack generating position 43 toward the cutting line 44. Here, the solid line (cutting lines 44, 45) in the figure indicates a state in which the tempered glass sheet is cut (through the front surface of the tempered glass sheet 10 to the back surface), and a broken line (cut line 48) indicates tempered glass. The board is not cut off.

That is, the cutting end point 42 shown in Fig. 7A is located on the cutting line 44 that has been cut. In other words, the cutting end point 42 is located on the side of the tempered glass sheet. Further, when the condition of the laser light is not appropriate, when the laser light is scanned along the line to cut 48 toward the cutting end point 42, the unexpected crack 46 extends from the crack generating position 43 toward the cutting line 44. Therefore, in self-tempered glass The sample 40 cut out from the plate 10 was formed into a convex portion 49, and the quality of the tempered glass plate (sample 40) after the cutting was deteriorated.

As described above, when the tempered glass sheet 10 is cut, the compressive stress generated in the region irradiated with the laser light (see FIG. 4) is used to suppress the tensile stress generated in the scanning direction of the laser light (see FIG. 5). The crack caused by the extension is cut off. Therefore, when the conditions of the laser light are not appropriate, there is a possibility that the stretching direction of the crack due to the tensile stress generated behind the scanning direction cannot be controlled, and the unexpected crack 46 is extended from the crack generating position 43 toward the cutting line 44. And the cutting line is separated from the cut line 48.

Fig. 7B is a view showing an example of a state in which the tempered glass sheet is cut in a case where the tempered glass sheet cutting method of the embodiment is used. In the cutting method of the tempered glass sheet of the present embodiment, the tempered glass is cut so as to be at an acute angle α1 with respect to the cutting line 44 toward the cutting end point 42 located at the cutting line (side surface) 44 of the tempered glass sheet. In the case of the plate, each unit irradiated to the tempered glass sheet is irradiated from the crack generating position 43 (i.e., at a specific position from the cutting end point 42 of the tempered glass sheet to a specific position before the cut end point 42). The irradiation energy of the laser light of the irradiation area is larger than the usual irradiation energy. Here, the normal irradiation energy means, for example, the irradiation energy of the laser light per unit irradiation area required for cutting the tempered glass sheet in a straight line. Further, the crack generating position 43 is the starting point of the unexpected crack 46 which extends toward the cutting line 44. The crack generation position 43 changes its position depending on the cutting conditions of the tempered glass sheet 10 (for example, the distance between the scanning position of the laser light and the cutting line 44 or the irradiation energy of the laser light).

Thus, by illuminating the irradiation area per unit of the tempered glass sheet The irradiation energy of the light is increased, and the tensile stress generated behind the scanning direction of the laser light can be increased. Thereby, the tempered glass sheet 10 can be cut while accurately controlling the direction in which the crack in the scanning direction is extended, and the unexpected crack 46 can be prevented from extending from the crack generating position 43 toward the cutting line 44. Thereby, the sample 40 can be cut along the line to cut 48.

At this time, the smaller the angle α1 between the line segment connecting the scanning position of the laser light and the cutting end point 42 and the cutting line 44 (the side surface of the tempered glass sheet 10), the easier it is to face the cutting line 44. Crack 46 outside. Thereby, for example, the smaller the angle α1 is, the larger the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet can be.

Further, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area is such that the output of the laser light is P (W), and the scanning speed of the laser light is set to v (mm/s), and the irradiation is performed. The beam diameter of the laser beam for the tempered glass plate 10 is set to When it is (mm), it can be represented by the following formula.

That is, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area is the laser light scanning the energy per area of the tempered glass sheet 10 per unit time (one second). Hereinafter, the irradiation energy of the laser light per unit irradiation area is also described as unit energy.

For example, according to the above formula 3, by making the moving speed (scanning speed) of the irradiation region of the laser light slow, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made large. Further, by increasing the output of the laser light, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be increased. Also, by making the area of the irradiated area of the laser light (ie, the beam diameter) When it is small, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made large. Further, by appropriately combining these methods, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made large.

Further, in the present embodiment, as the absorption coefficient α of the tempered glass sheet 10 is increased, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made small. When the absorption coefficient α is large, the energy absorbed by the tempered glass sheet 10 is increased, so that the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made small.

Further, as the thickness t of the tempered glass sheet becomes thicker, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made larger. When the thickness of the glass sheets to strengthen the case of thicker t necessary energy supplied to the toughened glass plate of 10 increases, and therefore, it is preferable to make the laser beam irradiated per unit area of the irradiation energy E (J / mm ²⁾ becomes Big. Further, as the thermal expansion coefficient of the tempered glass sheet 10 becomes large, the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made small. When the thermal expansion coefficient of the tempered glass sheet 10 is large, the tensile stress generated behind the scanning direction of the laser light becomes large, so that the irradiation energy E (J/mm ² ) of the laser light per unit irradiation area can be made small accordingly. .

FIG. 8A is a view showing another example of the cut state of the tempered glass sheet when the conditions of the laser light irradiated to the tempered glass sheet are not appropriate. In the example shown in FIG. 8A, the cutting end point 52 is disposed on the side surface 54 of the tempered glass sheet 10. Further, the line to cut 58 toward the cutting end point 52 becomes a straight line. As shown in FIG. 8A, when the condition of the laser light is inappropriate, when the laser light is scanned along the line to cut 58, the unexpected crack 56 extends from the crack generating position 53 toward the side 54 of the strengthened glass sheet 10. . Therefore, in the self-strengthening glass plate The cut sample 50 was formed into the convex portion 59, and the quality of the tempered glass sheet (sample 50) after the cutting was deteriorated.

Fig. 8B is a view showing another example of the state in which the tempered glass sheet is cut in the case where the tempered glass sheet cutting method of the embodiment is used. In the method of cutting a tempered glass sheet according to the present embodiment, when the tempered glass sheet is cut so as to be at an acute angle α2 with respect to the side surface 54 toward the cutting end point 52 of the side surface 54 of the tempered glass sheet, self-cracking occurs. In the section from the position 53 to the cutting end point 52, the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet is made larger than the normal irradiation energy.

As described above, by increasing the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet, the tensile stress generated in the scanning direction of the laser light can be increased. Thereby, the tempered glass sheet 10 can be cut while accurately controlling the direction in which the crack in the scanning direction is extended, and the unexpected crack 56 can be prevented from extending from the crack generating position 53 toward the side surface 54. Thereby, the sample 50 can be cut along the line to cut 58.

At this time, the smaller the angle α2 between the line segment connecting the scanning position of the laser light and the cutting end point 52 and the side surface 54 (the side surface of the tempered glass sheet 10), the more easily the unexpected crack is generated toward the side surface 56. . Thereby, for example, the smaller the angle α2 is, the larger the irradiation energy of the laser light per unit irradiation area irradiated to the tempered glass sheet can be. Further, in the example shown in Figs. 8A and 8B, since the line to cut 58 is a straight line, the angle α2 can also be expressed as an angle formed by the line to cut 58 and the side surface 54.

FIG. 9A is a view showing another example of the cut state of the tempered glass sheet when the conditions of the laser light irradiated to the tempered glass sheet are not appropriate. Figure 9A is from The graph obtained by strengthening the glass sheet 10 is observed above. When the sample 60 is cut out from the tempered glass sheet 10, the scanning of the laser light is started from the cutting start point 61, and the laser light is scanned along the line of the cutting line in the direction of the arrow shown in Fig. 9A, and ends at the cutting end point 62. Scanning of laser light.

As shown in FIG. 9A, when the condition of the laser light is inappropriate, when the laser light is scanned along the line to cut 68, the unexpected crack 66 extends from the crack generating position 63 toward the cutting line 64. Therefore, the sample 60 cut out from the tempered glass sheet 10 forms the convex portion 69, and the quality of the tempered glass sheet (sample 60) after cutting is deteriorated.

Fig. 9B is a view showing another example of the state in which the tempered glass sheet is cut in the case where the tempered glass sheet cutting method of the embodiment is used. In the method of cutting a tempered glass sheet according to the present embodiment, the tempered glass is cut so as to become an acute angle α3 with respect to the cutting line 64 toward the cutting end point 62 located at the cutting line (side surface) 64 of the tempered glass sheet. In the case of the plate, the irradiation energy of the laser light per unit irradiation area irradiated to the tempered glass sheet is larger than the normal irradiation energy in the interval from the crack generation position 63 to the cutting end point 62.

As described above, by increasing the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet, the tensile stress generated in the scanning direction of the laser light can be increased. Thereby, the tempered glass sheet 10 can be cut while accurately controlling the direction in which the crack in the scanning direction is extended, and the unexpected crack 66 can be prevented from extending from the crack generating position 63 toward the cutting line 64. Thereby, the sample 60 can be cut along the line to cut 68. At this time, in the example shown in FIG. 9B, as the scanning position of the laser light approaches the cutting end point 62, the cutting is performed. The angle α3 formed by the line 67 and the cutting line 64 (in this case, the tangent to the cutting line 64) becomes small.

In addition, as an example shown in FIG. 6 to FIG. 9B, the cutting method of the tempered glass sheet of the present embodiment can be widely applied to the side of the cutting end on the side of the tempered glass sheet to be opposite to the side of the tempered glass sheet. The case of sharpening the glass plate by cutting it into an acute angle.

According to the cutting method of the tempered glass sheet of the present embodiment described above, the tempered glass sheet can be cut by using laser light without deteriorating the quality.

Further, in the method of cutting a tempered glass sheet according to the present embodiment, when the tempered glass sheet is cut by scanning the laser light, the tempered glass sheet may be cooled while being irradiated around the irradiation region of the laser light. scanning. Fig. 10 is a cross-sectional view for explaining a cooling nozzle used in the method for cutting a tempered glass sheet according to the embodiment. As shown in FIG. 10, the cooling nozzle 28 is formed with a tapered cavity in such a manner that a gas flows inside the cooling nozzle 28. At this time, the tapered cavity is set such that the laser light 20 condensed by the lens 25 can pass through the inside of the cooling nozzle 28. Further, the cooling nozzle 28 is configured to be movable in synchronization with the movement of the irradiation area of the laser light (that is, at the same scanning speed as the laser light).

As the gas for cooling, for example, air or nitrogen or the like can be used. Further, in order to increase the cooling ability, a mist containing a small amount of moisture in the gas may be contained. Further, as the gas for cooling, a gas having a temperature lower than the temperature around which the tempered glass sheet is cut may be used. Further, as the gas for cooling, a gas having a heat transfer coefficient larger than the heat transfer coefficient of air may be used.

The diameter of the opening of the front end of the cooling nozzle 28 1. The distance Gap between the front end of the cooling nozzle 28 and the front surface 12 of the tempered glass sheet 10 can be arbitrarily determined. Here, the diameter of the opening of the front end of the cooling nozzle 28 The smaller the 1 is, the faster the flow rate of the gas ejected to the tempered glass sheet 10 is, so that the cooling ability in the front surface 12 of the tempered glass sheet 10 is improved. Further, the smaller the distance Gap between the front end of the cooling nozzle 28 and the front surface 12 of the tempered glass sheet 10, the more the cooling ability in the front surface 12 of the tempered glass sheet 10 is improved. Further, the cooling gas is supplied to the cooling nozzle 28 from, for example, a gas supply unit (not shown).

As described above, when the laser beam is scanned and the tempered glass sheet is cut, the laser beam is scanned while cooling the tempered glass sheet, and the direction in which the crack extends in the scanning direction can be more accurately controlled. Thereby, it is possible to more reliably suppress the crack from being separated from the planned cutting line when the tempered glass sheet is cut, and extending in the unexpected direction.

Fig. 11 is a view showing the distribution of stress generated at the center portion of the thickness of the tempered glass sheet 10 when the laser light is scanned on the tempered glass sheet 10 (without cooling). As shown in FIG. 11, a compressive stress 33 is generated in the irradiation region 22 of the laser light of the tempered glass sheet 10. Further, the tensile stress 35 is generated at a position X2 which is only rearward of the scanning direction of the distance D1 from the center X1 of the irradiation region 22 of the laser light. In the method of cutting a tempered glass sheet according to the present embodiment, the tensile stress 35 generated by the irradiation of the laser light acts on the end portion of the crack 30, and the compression in the irradiation region 22 of the laser light is used. The stress 33 suppresses the extension of the crack, thereby cutting the tempered glass sheet 10 while controlling the extending direction of the crack 30 behind the scanning direction.

Fig. 12 is a view (with cooling) showing the distribution of stress generated at the center portion of the thickness of the tempered glass sheet 10 when the laser light is scanned on the tempered glass sheet 10. Figure Similarly, in the case of 12, the compressive stress 33 is generated in the irradiation region 22 of the laser beam of the tempered glass sheet 10. Further, the tensile stress 35 is generated at a position X2' which is only rearward of the scanning direction of the distance D2 from the center X1 of the irradiation region 22 of the laser light. Further, in the case shown in Fig. 12, since the front surface of the tempered glass sheet 10 is cooled, the distance X2 between the position X1 where the compressive stress 33 is generated and the position X2' where the tensile stress is generated is the distance from the case where the cooling is not performed. D1 (refer to FIG. 11) is shorter. Therefore, when the front surface of the tempered glass sheet 10 is cooled, the position X1 at which the compressive stress 33 is generated can be made close to the position X2' at which the tensile stress is generated, so that the direction of the crack extending behind the scanning direction can be more accurately controlled. . Thereby, it is possible to more reliably suppress the crack from being separated from the planned cutting line when the tempered glass sheet is cut, and extending in the unexpected direction.

Further, in the above example, the case where the front surface of the tempered glass sheet 10 is cooled has been described, but the back surface of the tempered glass sheet 10 may be cooled, and the front and back sides of the tempered glass sheet 10 may be also provided. The way of cooling is made up. A cooling nozzle can also be used in the case where the back surface of the tempered glass sheet 10 is cooled.

Next, a tempered glass sheet cutting device for carrying out the above-described cutting method of the tempered glass sheet of the present embodiment will be described. Fig. 13 is a view for explaining the tempered glass sheet cutting device of the embodiment. The tempered glass sheet cutting device 70 of the present embodiment includes a laser output unit 71, a glass holding drive unit 72, a control unit 73, and a control program generation unit 74.

The laser output unit 71 outputs the laser light 20 for cutting the tempered glass sheet 10. As the light source of the laser light 20, for example, a UV laser (wavelength: 355 nm), a green laser (wavelength: 532 nm), and a semiconductor laser (wavelength: 808) can be used. Nm, 940 nm, 975 nm), fiber laser (wavelength: 1060 to 1100 nm), YAG laser (wavelength: 1064 nm, 2080 nm, 2940 nm), laser using a mid-infrared optical parametric oscillator (wavelength: 2600~3450 nm) and so on.

Here, in the case of using near-infrared laser light, it is necessary to add impurities such as Fe to the tempered glass sheet in order to increase the absorption in the near-infrared. When an impurity having absorption characteristics in the near-infrared is added, it also affects the absorption characteristics of the visible light region, and thus it may affect the color tone or transmittance of the tempered glass sheet. In order to prevent the above, as the light source of the laser light 20, a laser having a wavelength of 2500 to 5000 nm may be used. Since absorption due to molecular vibration of the glass itself occurs in a frequency band of 2,500 to 5,000 nm, it is not necessary to add impurities such as Fe.

The laser output unit 71 includes an optical system for adjusting the focus of the laser light. The power of the laser light (laser output), the beam diameter (focus) of the laser beam, the timing of the laser irradiation, and the like are controlled by the control unit 73. Further, the cooling nozzle 28 shown in Fig. 10 may be disposed in the irradiation portion of the laser beam. In this case, the flow rate of the gas ejected from the cooling nozzle can be controlled by the control unit 73.

The glass holding drive unit 72 holds the tempered glass sheet 10 as a processing target, and moves the tempered glass sheet 10 in a specific direction. In other words, the glass holding drive unit 72 moves the tempered glass sheet 10 such that the laser light is scanned along the line to cut of the tempered glass sheet 10. The glass holding drive unit 72 is controlled using the control unit 73. The glass holding drive unit 72 can also fix the tempered glass sheet 10 to be processed by using a porous plate or the like. Moreover, the glass holding drive unit 72 may also include a map for determining the position of the tempered glass sheet 10. Like a detector. The processing precision of the tempered glass sheet 10 can be improved by including an image detector for positioning.

Further, in the tempered glass sheet cutting device 70 shown in FIG. 13, the tempered glass sheet 10 is moved by the glass holding drive unit 72 so that the irradiation region of the laser light 20 moves on the tempered glass sheet 10. At this time, the laser output unit 71 is fixed. However, by fixing the tempered glass sheet 10 held by the glass holding drive unit 72, the laser output unit 71 is moved, and the irradiation region of the laser light 20 is moved on the tempered glass sheet 10. Further, the tempered glass sheet 10 and the laser output unit 71 held by the glass holding drive unit 72 may be configured to move.

The control unit 73 controls the laser output unit 71 and the glass holding drive unit 72 based on the control program generated by the control program generation unit 74.

The control program generation unit 74 generates and controls the irradiation of the tempered glass based on at least one of the thermal expansion coefficient and the thickness of the tempered glass sheet 10, the absorption coefficient of the tempered glass sheet with respect to the laser light, and the residual tensile stress of the intermediate layer 17 of the tempered glass sheet. The control program for the illumination energy of the laser light per unit of illumination area of the panel.

Further, the control program generation unit 74 generates a control program for generating a self-cracking position when the tempered glass sheet is cut so as to be perpendicular to the side surface of the tempered glass sheet at the cutting end point on the side surface of the tempered glass sheet. In the interval from the front to the end of the cutting, the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass plate is larger than the normal irradiation energy. For example, the control program generation unit 74 generates an area for controlling the irradiation area of the laser light (ie, the beam diameter) based on the information of the planned cutting line and the position information (current position) of the laser light. ), the output of the laser light and the control program of the scanning speed of the laser light.

Specifically, for example, the control program generation unit 74 is based on the physical properties of the tempered glass sheet 10 set in advance (thermal expansion coefficient, thickness, absorption coefficient of the tempered glass sheet with respect to the laser light, and residual stretching of the intermediate layer 17 of the tempered glass sheet). The stress, etc., determines the irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet when the straight line portion is cut. And, according to the determined unit energy, the information of the planned cutting line, and the position information (current position) of the laser light, an area for controlling the irradiation area of the laser light (ie, the beam diameter) is generated. ), the output of the laser light and the control program of the scanning speed of the laser light.

As described above, according to the invention of the present embodiment, it is possible to provide a method for cutting a tempered glass sheet and a tempered glass sheet cutting device which use a laser beam to cut the tempered glass sheet without deteriorating the quality.

<Reference Example 1>

Next, a case where the crack stretching method is different between the method of cutting the tempered glass sheet and the method of cutting the non-reinforced glass sheet will be described with reference to Figs. 14 to 16 . Fig. 14 is a table showing the results of cutting of the tempered glass sheet. Fig. 15 is a table showing the results of cutting about the non-reinforced glass sheet. Fig. 16 is a table showing the results of cutting about the tempered glass sheet (reference example) and the non-reinforced glass sheet (comparative example). The cutting result shown in Fig. 16 is a cutting result when the diameter of the spot light of the laser light is made smaller than the cutting result shown in Figs. 14 and 15 .

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-reinforced glass plate was prepared. The tempered glass sheets of Reference Examples 101 to 103 and 106 to 108 were similar in size to the non-reinforced glass sheets of Comparative Examples 104 to 105 and 109 to 110 by chemical strengthening method (rectangular, long side 100 mm, short side 60 mm). Manufactured with a glass plate of the same chemical composition, with a plate thickness of 0.7 mm). The tempered glass sheet has an internal residual tensile stress (CT) of 30.4 MPa, a maximum residual compressive stress (CS) of 763 MPa, and a compressive stress layer (front layer or back layer) of thickness (DOL) of 25.8 μm. Here, the internal strain energy U _CT is 4.04 J/m ² .

In the reference examples 101 to 103, 106 to 108, and the comparative examples 104 to 105 and 109 to 110, the same conditions were used except for the type of the glass plate (the difference between the reinforcement and the non-reinforcement), the output of the light source, and the diameter of the laser spot. The cutting experiment was carried out.

(common conditions)

Laser light source: fiber laser (wavelength 1070 nm)

Angle of incidence of laser light towards the glass plate: 0°

Convergence angle of laser light: 2.5°

Spotlight position of the laser light: 23 mm away from the front side of the glass plate on the light source side

Absorption coefficient of glass plate relative to laser light: 0.09 cm ^-1 (0.009 mm ^-1 )

Glass plate thickness t: 0.07 cm (0.7 mm)

Young's modulus of glass plate Y: 74000 MPa

α×t: 0.0063

Nozzle outlet diameter: 1 mm

Flow rate of cooling gas from the nozzle (compressed air at room temperature): 30 L/min

Target cut position: a line parallel to the short side of the glass plate (10 mm from one short side and 90 mm from the other short side)

Cutting speed: 2.5 mm/s

In the reference examples 101 to 103 and the comparative examples 104 to 105 shown in FIG. 14 and FIG. 15, the diameter of the laser spot in the front surface of the glass plate is used. Set to 1 mm. Further, in Reference Examples 106 to 108 and Comparative Examples 109 to 110 shown in FIG. 16, the diameter of the laser spot in the front surface of the glass plate was used. Set to 0.1 mm.

After cutting, the cut surface of the glass plate was observed with a microscope. The stripe pattern observed on the cut surface of the glass sheet indicates the temporal change of the position of the front end of the crack which is intermittently stretched. The crack extension is known from the shape of each line of the stripe pattern. In the micrographs shown in Figs. 14 to 16, the representative lines of the stripe pattern are emphasized by the thicker white lines.

Further, it was visually observed that the cracks in the laser irradiation and the gas cooling were interrupted during the cutting of the glass sheet.

The results of each experiment are shown in Figures 14-16. In FIGS. 14 to 16, the case where the glass plate is cracked (the case where it can be cut) is indicated as "○", and the case where the glass plate is not cracked (the case where the cutting is impossible) is expressed as "×". .

The stripe pattern line in the micrograph of the cut surface of Figs. 14 to 16 indicates the position of the front end of the crack at a certain point of time.

The "free diffusion" in Figs. 14 to 16 means that after the laser irradiation or the like is interrupted, the crack extends toward the short side of the two short sides of the glass plate which is closer to the cutting position.

The amount of convexity and straightness error indicates the amount of error when the glass plate is cut. That is, when the glass plate is viewed from the upper side, the cutting line of the glass plate is offset from the planned cutting line (indicated by the X-axis of the graph) (indicated by the Y-axis of the graph). The smaller the amount of convexity and straightness error (that is, the absolute value of the Y-axis), the smaller the glass plate is. The broken line is cut.

As shown in Fig. 15, in the cutting of the non-tempered glass sheets of Comparative Examples 104 to 105, it is understood from the micrograph of the cut surface that the both ends of the glass sheet in the thickness direction are the center of the thickness direction of the glass sheet. The tendency to split. Further, if the laser irradiation and the gas cooling are interrupted during the cutting, the extension of the crack is stopped. Moreover, in the cutting of the non-reinforced glass sheet, a large light source output is required. Further, in the cutting of the non-reinforced glass sheet, the amount of error in the amount of convexity and straightness is increased.

On the other hand, in the cutting of the tempered glass sheets of Reference Examples 101 to 103 shown in FIG. 14 , it can be seen from the micrograph of the cut surface that the center portion of the glass sheet in the thickness direction is thicker than the thickness of the glass sheet. The tendency of the ministry to split first. This is because the residual tensile stress is originally present inside the tempered glass sheet, and the crack is stretched by the internal residual tensile stress. Further, if the laser irradiation and the gas cooling are interrupted during the cutting, the crack extends in the unexpected direction. According to the results, it is understood that the stretching of the crack due to the internal residual tensile stress is suppressed by the irradiation of the laser light. Further, in the cutting of the tempered glass sheet, the amount of convexity and straightness error is smaller than that of the unreinforced glass sheet. The same result was obtained in the cutting of the tempered glass sheets of Reference Examples 106 to 108 shown in Fig. 16 .

Further, as shown in FIG. 16, when the diameter of the laser spot is made small (Reference Examples 106 to 108), the tempered glass sheet can be cut off from the light source smaller than the reference examples 101 to 103. Further, in Reference Examples 106 to 108, the amount of convexity and straightness error was smaller than those of Reference Examples 101 to 103 shown in FIG. That is, in Reference Examples 106 to 108, the accuracy can be cut off more accurately than the reference examples 101 to 103. Glass plate. Further, as shown in Reference Examples 106 to 108, the lower the light source output, the smaller the amount of convexity and straightness error. In particular, in Reference Example 108, the amount of convexity was extremely small and was 15 μm.

On the other hand, when the diameter of the laser spot is made small, the non-reinforced glass sheet cannot be cut. That is, as shown in Comparative Example 109, when the output of the light source was set to 200 W, the non-reinforced glass sheet was melted and could not be cut. That is, the temperature of the non-reinforced glass is not more than the cold point and cannot be cut. Further, as shown in Comparative Example 110, when the output of the light source was set to 100 W, the non-reinforced glass sheet did not change. Therefore, when the diameter of the laser spot is made small (for example, the plate thickness is not reached), the unreinforced glass plate cannot be cut regardless of the output of the light source.

Thus, in the method of cutting the tempered glass sheet and the method of cutting the non-reinforced glass sheet, the mechanism of cutting is fundamentally different, and the manner of stretching the crack is completely different. Therefore, in the present invention, an unpredictable effect is obtained by the cutting method of the non-reinforced glass sheet. Hereinafter, the reason will be described.

For example, in the method of cutting a non-reinforced glass sheet, a thermal stress field is formed in the glass sheet using both the laser light and the cooling liquid to generate a tensile stress required 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 rapidly cooled by the cooling liquid to generate tensile stress to cause crack propagation. Therefore, the extension of the crack is performed only by the irradiation energy of the laser light, and it is necessary to set the power (W) of the laser light irradiated to the glass plate to be large.

In the method as described above, the position of the front end of the cut glass formed on the glass sheet is determined by the position of the cooling liquid for cooling the glass sheet. The reason is A tensile stress is generated at the position of the coolant. Therefore, if the heating by the laser light or the cooling by the cooling liquid is interrupted during the cutting, the extension of the crack is stopped.

Fig. 17 is a view for explaining the stress acting on cutting the non-reinforced glass sheet using laser light. In Fig. 17, a plan view of the non-reinforced glass sheet 110 and a distribution of stress generated at the center portion of the thickness of the non-reinforced glass sheet 110 are shown. As shown in FIG. 17, when the non-reinforced glass plate 110 is irradiated with laser light, the compressive stress 133 acts in the irradiation region 122 of the laser light. This compressive stress 133 is a thermal stress generated by irradiation of laser light. Further, in order to equalize the compressive stress 133, a tensile stress 135 is generated in the scanning direction of the irradiation region 122. The tensile stress 135 acts on the crack 130 to cut the non-reinforced glass sheet 110.

As shown in the graph of Fig. 17, in the non-reinforced glass sheet 110, the internal residual tensile stress CT is substantially zero. Therefore, the tensile stress 135 acting on the crack 130 when the non-reinforced glass sheet 110 is cut is generated only by irradiation of laser light. Therefore, in order to increase the tensile stress 135, it is necessary to increase the irradiation energy of the laser light or increase the diameter of the laser spot. Therefore, in the non-reinforced glass sheet 110, it is difficult to cut the glass having a small absorption rate of the laser light.

Further, when the non-reinforced glass sheet 110 is cut, the stretching of the crack is controlled by the irradiation energy of the laser light and the scanning speed. At this time, if the irradiation energy of the laser light is smaller than the irradiation energy required for the cutting, the extension of the crack stops. That is, as shown in the graph of Fig. 17, in order to stretch the crack 130, it is necessary to apply a tensile stress larger than the tensile stress S_th required for the extension of the crack 130 to the crack 130. Since the internal residual tensile stress CT in the non-reinforced glass sheet 110 is substantially Zero, it is necessary to use only the irradiation energy of the laser light to generate a tensile stress larger than the value of the tensile stress S_th.

On the other hand, in the method of cutting a tempered glass sheet, since the internal residual tensile stress is present inside the glass sheet, it is not necessary to use the irradiation energy of the laser light only when the non-reinforced glass sheet is cut. Large tensile stress. Further, when the internal residual tensile stress is a tensile stress which is larger than the tensile stress S_th required for the stretching of the crack, if a force is applied to the tempered glass sheet to cause cracks, the tensile stress is internally retained. The crack stretched by itself. On the other hand, since the internal residual tensile stress is present entirely inside the glass sheet, the crack extends in an unexpected direction as long as the crack is not controlled.

Therefore, in the present invention, the intermediate layer at the center of the irradiation region is caused to have a tensile stress or a compressive stress which is smaller than the value of the internal residual tensile stress, and the crack extension due to the internal residual tensile stress is suppressed. That is, by irradiating the laser light, the residual tensile stress in the intermediate layer of the tempered glass sheet is made smaller than the tensile stress S_th required for the stretching of the crack, and the stretching of the crack is controlled.

Fig. 18 is a view showing an example of stress acting when the tempered glass sheet is cut by laser light. In Fig. 18, a plan view of the tempered glass sheet 10 and a distribution of stress generated at the center portion of the tempered glass sheet 10 are shown. As shown in FIG. 18, when the tempered glass sheet 10 is irradiated with laser light, the compressive stress 33 acts in the irradiation region 22 of the laser light. Further, a tensile stress 35 is generated behind the scanning direction of the irradiation region 22. Further, by adding the internal residual tensile stress to the tensile stress 35, a tensile stress larger than the tensile stress S_th required for the stretching of the crack is generated, and the tempered glass sheet 10 is applied by acting on the crack 30. Cut off. At this time, the extension of the crack 30 is controlled by the compressive stress 33.

As shown in the graph of FIG. 18, there is an internal residual tensile stress CT in the tempered glass sheet 10. Therefore, the tensile stress 35 required for the extension of the crack 30 can also be small. In other words, the compressive stress 33 generated by the laser light required to apply the tensile stress which is larger than the tensile stress S_th (the tensile stress required for the stretching of the crack 30) to the crack 30 can be made small.

Here, since the compressive stress 33 or the tensile stress 35 required when the tempered glass sheet 10 is cut can be made smaller than the stress required when the non-reinforced glass 110 is cut, the irradiation energy of the laser light can be made small or the ray can be made The diameter of the spot is reduced. Therefore, the cutting accuracy can be improved. Further, even a glass having a small absorption rate of laser light can be easily cut.

Fig. 19 is a view showing another example of stress acting when the tempered glass sheet is cut by laser light. In Fig. 19, a plan view of the tempered glass sheet 10 and a distribution of stress generated at the center portion of the tempered glass sheet 10 are shown. In the tempered glass sheet 10 shown in Fig. 19, the internal residual tensile stress CT is larger than the tensile stress S_th required for the stretching of the crack 30. That is, as shown in FIG. 19, when the tempered glass sheet 10 is irradiated with the laser light, the tensile stress 37 which is smaller than the value of the internal residual tensile stress CT is generated in the irradiation region 22 of the laser light. Here, the tensile stress 37 is a resultant force of the compressive stress 33 generated by the irradiation of the laser light and the internal residual tensile stress CT. Further, a tensile stress 35 is generated behind the scanning direction of the irradiation region 22. In this case, the stretching of the crack 30 can be suppressed by making the tensile stress 37 which is smaller than the value of the internal residual tensile stress CT smaller than the tensile stress S_th required for the stretching of the crack 30.

In the case shown in Fig. 19, it is also possible to cut the tempered glass sheet 10 The tensile stress 37 or the tensile stress 35 which is smaller than the value of the internal residual tensile stress CT is smaller than the stress required when the non-reinforced glass 110 is cut, so that the irradiation energy of the laser light can be made small or the diameter of the laser spot can be made small. Become smaller. Therefore, the cutting accuracy can be improved. Further, even a glass having a small absorption rate of laser light can be easily cut.

As described above, when the tempered glass sheet 10 is cut, the balance of the internal residual tensile stress CT, the irradiation energy of the laser light, and the scanning speed is maintained, and the crack 30 is prevented from being freely diffused to control the stretching of the crack 30. Therefore, if the irradiation energy of the laser light is too small, the tensile stress 37 which is smaller than the value of the internal residual tensile stress CT is 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 and is freely diffused ( The situation in Figure 19).

Thus, in the method of cutting the tempered glass sheet and the method of cutting the non-reinforced glass sheet, the mechanism of cutting is fundamentally different, and the manner of stretching the crack is completely different. Therefore, in the present invention, an unpredictable effect is obtained by the cutting method of the non-reinforced glass sheet.

<Reference Example 2>

Next, Reference Example 2 will be described. In Reference Example 2, the relationship between the internal strain energy U _CT and the minimum value of the severable irradiation energy E _L , that is, the critical irradiation energy Ec will be described.

In Reference Example 2, the relationship between the critical irradiation energy Ec and the 21 samples 1 to 21 in which the internal strain energy U _{CT was} different was investigated. Furthermore, samples 18 to 21 are non-reinforced glass sheets.

Fig. 20 is a view showing the shape of a line to cut in Reference Example 2. As shown in FIG. 20, the line to cut of Reference Example 2 includes two straight portions and constitutes a crank shape. 2 corners of the shape (curvature radius R = 5 mm).

As a glass plate for chemical strengthening, a glass raw material obtained by mixing and adjusting a plurality of raw materials is melted, and the molten glass to be melted is formed into a plate shape. After it was allowed to cool to about room temperature, it was cut, cut, and double-sided mirror-polished, thereby producing a glass plate having a specific thickness of 50 mm × 50 mm. The glass raw material is prepared by changing the amount of iron oxide (Fe ₂ O ₃ ) powder added to the substrate of the same blending ratio so that the absorption coefficient α of the glass plate with respect to the laser light is a desired value.

Each glass plate for chemical strengthening is represented by mass % of oxides, and contains SiO ₂ : 60.9%, Al ₂ O ₃ : 12.8%, Na ₂ O: 12.2%, K ₂ O: 5.9%, and MgO: 6.7%. CaO: 0.1%, SrO: 0.2%, BaO: 0.2%, and ZrO ₂ : 1.0%, and a specific amount of iron oxide (Fe ₂ O ₃ ) was contained in addition.

Each of the tempered glass sheets is prepared by immersing the above-mentioned glass plate for chemical strengthening in a KNO ₃ molten salt, performing ion exchange treatment, and then cooling it to about room temperature. The processing conditions such as the temperature of the KNO ₃ molten salt or the immersion time are set such that the internal residual tensile stress CT becomes a desired value.

The internal residual tensile stress CT (MPa) of the tempered glass sheet is measured by the surface stress meter FSM-6000 (manufactured by Orthogonal Separation Co., Ltd.) to measure the surface compressive stress CS (MPa) and the thickness of the compressive stress layer (front layer and back layer) DOL (μm) The calculated value and the thickness t ₁ (μm) of the tempered glass sheet were calculated using the following formula 1.

CT=(CS×DOL)/(t ₁ -2×DOL)...Form 1

The internal strain energy U _CT (J/m ² ) was determined according to the following formula 2 using the Young's modulus Y (MPa) of the tempered glass sheet.

U _CT ={CT ² ×(t ₁ -2×DOL)}/(2×Y)...Form 2

The irradiation energy of the laser light per unit irradiation area is set to Pe (W) when the effective laser output that is not reflected by the tempered glass sheet is set, and the scanning speed of the laser light is set to v (mm/s). The beam diameter of the laser light irradiated to the tempered glass plate 10 is set to (mm), by Pe/(v× ) (Unit: J/mm ² ) indicates. However, in order to judge the cuttability, it is preferable to use it to multiply the beam diameter. (mm) The obtained irradiation energy E _L (J/mm) per unit length of the laser light. The detailed reasons are described later. This irradiation energy E _L (J/mm) is shown in the following formula 4. Furthermore, the effective laser output Pe(W) can be expressed as Pe=P×(1-r/100) using the laser output P(W) and the reflectance r(%) in the strengthened glass plate.

E _L =Pe/v... Equation 4

The critical irradiation energy Ec which is the critical value of the irradiation energy E _L of the samples 1 to 11 is obtained by repeatedly cutting the irradiation energy E _L by about 1 (J/mm). At this time, in a state where the scanning speed v (mm/s) of the laser light is fixed, only the laser output P (W) is changed by 2.5 W each time.

Further, the critical irradiation energy Ec of the samples 18 to 21 of the non-reinforced glass plate was determined by repeating the cutting by changing the irradiation energy E _L by about 4 (J/mm). At this time, in a state where the scanning speed v (mm/s) of the laser light is fixed, only the laser output P (W) is changed by 10 W each time.

On the other hand, the critical irradiation energy Ec of the samples 12 to 17 was obtained by repeating the cutting by slowly changing the irradiation energy E _L . At this time, in a state where the laser output P (W) is fixed, only the scanning speed v (mm/s) of the laser light is changed by 0.25 mm/s each time.

Fig. 21 is a table showing the laser wavelength λ, the internal strain energy U _CT , the critical irradiation energy Ec, and the conditions for deriving the two with respect to the samples 1 to 21. From the left row of the table, the laser wavelength λ (nm), the sample number, the Young's modulus Y (MPa) of the tempered glass plate, the linear expansion coefficient α _L (K ^-1 ), and the density ρ (g/mm) are sequentially indicated. ³ ), specific heat c (J/g/K), thickness t (mm), absorption coefficient α (mm ^-1 ), reflectance r (%) in tempered glass sheet, surface compressive stress CS (MPa), front layer And the thickness of the back layer DOL (μm), internal residual tensile stress CT (MPa), internal strain energy U _CT (J / m ² ), scanning speed of laser light v (mm / s), beam diameter of laser light (mm), laser output P (W), effective laser output Pe (W), critical irradiation energy Ec (J / mm), critical absorption energy Ea (J / mm), critical cutoff index Kc (N / Mm).

As shown in Fig. 21, regarding samples 1 to 11, 18 to 21, a fiber laser (center band: 1070 nm) is used for the light source of the laser light, and samples 12 to 17 are used for the source of the laser light. Cr:ZnSe laser (center band: 2950 nm) of the optical parametric oscillator.

Moreover, since the materials of any of the samples are the same, as shown in Fig. 21, the Young's modulus Y = 74000 MPa, the linear expansion coefficient α _L = 9.8 × 10 ^-6 K ^-1 , and the density ρ = 2.48 × 10 ^{- 3} g/mm ³ and specific heat c=0.918 J/g/K are common.

Furthermore, as shown in FIG. 21, regarding the samples 1 to 11, the beam diameter is set. =0.1 mm, for sample 12~17, set to beam diameter = 0.2 mm. Also, regarding the sample 18 of the non-reinforced glass plate, the beam diameter is set to =0.5 mm, for sample 19, set to beam diameter =0.8 mm, for sample 20, set to beam diameter =1.0 mm, for sample 21, set to beam diameter =2.0 mm.

Also, for all samples, a diameter of 1 mm is used from the side of the laser irradiation The nozzle sprayed air at a flow rate of 15 L/min. Here, the distance (gap) between the tempered glass plate and the tip end of the nozzle is set to 3 mm.

Fig. 22A is a graph showing the dependence of the internal strain energy U _CT of the critical irradiation energy Ec shown in the table of Fig. 21. The horizontal axis of Fig. 22A is the internal strain energy U _CT (J/m ² ), and the vertical axis is the critical irradiation energy Ec (J/mm). In Fig. 22A, the ● mark indicates samples 1 to 11, 18 to 21 (laser wavelength λ = 1070 nm), and the mark ○ indicates samples 12 to 17 (laser wavelength λ = 2950 nm).

As shown in FIG. 21 and FIG. 22A, when the laser beam has an internal strain energy U _CT ≧2.5 J/m ² at a laser wavelength of λ=1070 nm, the critical irradiation energy Ec=9-15 J/mm. Stable (samples 1 to 10). On the other hand, when the internal strain energy U _CT <2.5 J/m ² , the enthalpy (specifically, several times) is increased until the critical irradiation energy Ec=56 J/mm (sample 11). As the critical irradiation energy Ec rises, the cutting accuracy also deteriorates in the sample 11. From this result, it is understood that when the tempered glass sheet is cut, by setting the internal strain energy U _CT ≧2.5 J/m ² , it is possible to cut the irradiation energy with a small precision.

Further, the sample 18 of the non-reinforced glass sheet could not be cut. That is, if the plate thickness is less than t (=0.7 mm), the beam diameter is =0.5 mm, the sample of the non-reinforced glass plate cannot be cut. Moreover, regarding the beam diameter Sample of =0.8 mm, 19, critical illumination energy Ec = 83 J/mm, with respect to beam diameter Sample 20 with =1.0 mm, critical illumination energy Ec=76 J/mm, with respect to beam diameter Sample 21 of =2.0 mm, critical illumination energy Ec = 65 J/mm. That is, as the beam diameter increases, the critical irradiation energy Ec gradually decreases. Here, the larger the beam diameter, the farther the center of the laser light is from the front end of the crack, and the cutting accuracy is lowered. Therefore, when cutting the tempered glass sheet, the beam diameter It is preferably set to have a thickness t or less, and more preferably 1/2 or less of the thickness t.

According to the graph of Fig. 22A, it is considered that the internal strain energy U _CT = 2.5 J/m ² or so, and the switching of the cut mode is generated. Specifically, as the crack extension energy for cutting the tempered glass sheet, it is considered that when the internal strain energy U _CT <2.5 J/m ² , in addition to the internal strain energy, the irradiation energy of the laser light is also required (refer to the figure). 18) In the case of the internal strain energy U _CT ≧ 2.5 J/m ² , only the internal strain energy is obtained (refer to Fig. 19).

Further, by changing the laser wavelength λ from 1070 nm to 2950 nm, the absorption coefficient α of the strengthened glass plate is increased from 0.011 mm ^-1 to 0.59 mm ^-1 . Therefore, as shown in Figs. 21 and 22, when the internal strain energy U _CT ≧ 2.5 J/m ² , the critical irradiation energy Ec = 9 to 15 J/mm (sample 1 to 10) can be lowered to 2 points. The irradiation energy Ec=0.3~0.5 J/mm (sample 12~15).

Thus, by setting the laser wavelength to about 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. Moreover, it is not necessary to greatly change the irradiation conditions of the laser light depending on the composition of the tempered glass sheet.

Further, as described above, the tempered glass can be placed on a platen larger than the cut tempered glass plate, and cut in a more stable state. Moreover, since the transmission of light is reduced, there is no need for processing. Further, since the reflected light in the end surface of the tempered glass sheet is also drastically reduced, it is less likely to cause adverse effects.

In addition, when the laser wavelength λ is 2950 nm, as in the case of 1070 nm, if the internal strain energy U _CT <2.5 J/m ² , the temperature rises sharply until the critical irradiation energy Ec=0.9 to 1.2 J/mm or The above (samples 16 and 17). With the increase in the critical irradiation energy Ec, the cutting accuracy was also deteriorated in the samples 16 and 17. According to the results, it can be seen that when the tempered glass sheet is cut at the laser wavelength λ=2950 nm, by setting the internal strain energy U _CT ≧2.5 J/m ² , it is possible to cut the irradiation energy with a small precision. Broken.

Here, the energy for cutting in the critical irradiation energy Ec is the energy (hereinafter referred to as critical absorption energy) Ea absorbed by the tempered glass sheet. The critical absorption energy Ea (J/mm) can be used as the critical irradiation energy Ec (J/mm), the absorption coefficient α (mm ^-1 ), and the thickness t ₂ (mm), which is expressed by the following formula according to the law of Lambert-Beer law. .

Ea=Ec×exp(-α×t ₂ )... Equation 5

As shown in Fig. 21, regarding the value of the critical absorption energy Ea (J/mm), even when the laser wavelength λ is 2950 nm and the case of 1070 nm, there is almost no difference.

In order to eliminate the influence caused by the thickness or material of the tempered glass sheet, it is more general, and the thermal stress (critical compressive stress) σc generated by the internal heating (temperature change ΔT) using the critical absorption energy Ea is examined. . The critical compressive stress σc is the minimum compressive stress required to cut. Here, the critical compressive stress σc is a "critical compressive stress" because it is a compressive stress when it is based on the internal residual tensile stress CT. However, as shown in FIG. 18 and FIG. 19, the internal residual tensile stress CT and the criticality are considered in consideration of the stress generated at the center portion of the thickness of the tempered glass sheet. The resultant force of the compressive stress σc is expressed, and thus there is also a case where it is a tensile stress.

The critical compressive stress σc is as shown in Figs. 18 and 19 and has a Gaussian distribution. The integral value of the critical compressive stress σc (the area of the hatched portion in Figs. 18 and 19) determines whether or not the cut can be made. If the internal strain energy U _{CT is the} same, it is considered that the integral value of the critical compressive stress σc is fixed without depending on the thickness t and material of the tempered glass sheet. Width and beam diameter due to the distribution of critical compressive stress σc Proportional, so the integral value of the critical compressive stress σc can also be considered as σc× Proportionate.

Here, for simplification, it is assumed that the thickness t of the tempered glass sheet does not change even by internal heating, and is restrained between the front layer 13 and the back layer 15, whereby the critical compressive stress σc is generated. That is, consider the two-end constraint model.

The critical compressive stress σc (MPa) can be expressed by the following formula 6 by using Young's modulus Y (MPa), linear expansion coefficient α _L (K ^-1 ), and temperature change ΔT (K).

Σc=Y×α _L ×ΔT...Form 6

Further, the temperature change ΔT of the tempered glass sheet caused by the supply of the critical absorption energy Ea can be obtained from ΔT = (critical absorption energy) / (thermal capacitance of the tempered glass sheet of the laser irradiation portion).

Here, if the laser irradiation area is set to S ₁ (mm ² ), (critical absorption energy) can be used by dividing the critical absorption energy Ea (J/mm) by (mm) The critical absorbed energy per unit area Ea/ (J/mm ² ), and by Ea×S ₁ / (J) said.

Further, if the reinforcing area of the heating area of the glass plate is set to S ^₂ (mm _2), the (enhanced laser irradiated portion of the thermal capacity of the glass plate) may be used to strengthen the glass sheet of a thickness t ₂ (mm), a density ρ (g/mm ³ ), specific heat c (J/g/K), and represented by S ₂ × t ₂ × ρ × c (J/K).

Therefore, the temperature change ΔT(K) can be expressed by the following formula 7.

By substituting the formula 7 into the formula 6, the critical compressive stress σc (MPa) can be expressed by the following formula 8.

Here, for simplification, considering that S ₁ /S ₂ = fixed, σc × which is proportional to the integral value of the critical compressive stress σc to be obtained It can be represented by the following formula 9.

The Kc of Formula 9 is named as the critical cutoff index. The smaller the value of the critical cutoff index Kc indicating the critical value that can be cut, the easier the cutting is, and the larger the value of the critical cutoff index Kc, the more difficult it is to cut. Thus, the cutting property can be judged based on the irradiation energy E _L (J/mm) of the laser light per unit length shown in Formula 4.

The Young's modulus Y, the linear expansion coefficient α _L , the density ρ, and the specific heat c constituting the critical cutting index Kc each have temperature dependence, but the value of room temperature is always used as an index.

The critical cutoff index Kc (N/mm) is shown in the rightmost row of FIG.

Fig. 22B is a graph showing the dependence of the internal strain energy U _{CT on} the critical cutoff index Kc shown in the table of Fig. 21. The horizontal axis of Fig. 22B is the internal strain energy U _CT (J/m ² ), and the vertical axis is the critical cutoff index Kc (N/mm). In Fig. 22B, the ● mark indicates samples 1 to 11, 18 to 21 (laser wavelength λ = 1070 nm), and the mark ○ indicates samples 12 to 17 (laser wavelength λ = 2950 nm).

21, FIG. 22B, no matter how much the laser wavelength λ, if the glass sheets to strengthen internal strain energy ^{_{U CT ≧ 2.5 J / m 2}} , the critical cut index Kc = 50 N / mm and about stable (sample 1~10, 12~15). On the other hand, if the internal strain energy U _{CT is} <2.5 J/m ² , the critical cutoff index Kc=150 N/mm (sample 16) or more than 200 N/mm (samples 11 and 17). Further, in the case of a non-reinforced glass sheet, it exceeds 250 N/mm (samples 18 to 21). Here, the smaller the beam diameter, the larger the critical cutting index Kc, and if the beam diameter is 0.5 mm or less, the cutting is impossible (sample 18).

As the critical cutoff index Kc rises, the cutting accuracy also deteriorates. From this result, it is understood that when the tempered glass sheet is cut, by setting the internal strain energy U _CT ≧2.5 J/m ² , it is possible to cut the irradiation energy with a small precision. Further, the larger the beam diameter, the farther the center of the laser light is from the front end of the crack, and the cutting accuracy is lowered. Therefore, the beam diameter It is preferably set to have a thickness t ₂ (mm) or less, and more preferably 1/2 or less of the thickness t ₂ (mm).

The cutting index K at the irradiation energy E _L (J/mm) per unit length is represented by the following formula 10 by substituting Ec in the formula 5 with E _L and substituting Ea in the formula 9. Here, if the cutting index K is equal to or greater than the critical cutting index Kc, it can be cut.

K=E _L ×exp(-α×t ₂ )×(Y×α _L )/(t ₂ ×ρ×c) Equation 10

Further, by substituting Formula 4 into Formula 10, the following Formula 11 is obtained.

K=Pe/v×exp(−α×t ₂ )×(Y×α _L )/(t ₂ ×ρ×c) Equation 11

According to Fig. 22B, if the internal strain energy U _CT ≧ 2.5 J/m ² , the critical cutoff index Kc is about 50 N/mm, and therefore, the irradiation energy E _L which can satisfy the cutting index K≦150 N/mm is sufficiently cut. Broken. On the other hand, according to Fig. 22B, if the internal strain energy U _CT < 2.5 J/m ² , the critical cutoff index Kc becomes 150 N/mm or more, and therefore, the irradiation energy satisfying the cutoff index K≦150 N/mm is satisfied. E _L cannot be cut or difficult to cut. By setting the internal strain energy U _CT ≧2.5 J/m ² and the irradiation energy E _L satisfying the cutting index K≦150 N/mm, the irradiation energy can be cut with a small precision. By setting the irradiation energy E _L which satisfies the cutting index K ≦ 100 N/mm, it is possible to cut the irradiation energy finer with a smaller precision.

Example <Example 1>

Hereinafter, a first embodiment of the present invention will be described. In Example 1 shown below, a tempered glass sheet having a thickness of 0.8 mm, a surface compressive stress CS of 818 MPa, a thickness DOL of 27.4 μm each of the front and back layers, and a residual tensile stress CT of 30 MPa was used. .

The residual tensile stress of the tempered glass sheet is measured by the surface stress meter FSM-6000 (manufactured by Ohara, Ltd.) to measure the surface compressive stress CS and the depth DOL of the compressive stress layer (front layer and back layer), and the measured value and the tempered glass sheet are used. The thickness t is obtained by calculation using Equation 12 below.

CT=(CS×DOL)/(t-2×DOL)... Equation 12

In the present embodiment, the sample 80 of the shape shown in Fig. 23 was cut from the strengthened glass plate 10 (in the case of the present embodiment, 50 mm × 90 mm). That is, when the sample 80 is cut out from the tempered glass sheet 10, scanning of the laser light is started from the cutting start point 81, and the laser light is directed along the line to cut along the direction of the arrow shown in FIG. Scanning ends the scanning of the laser light at the cutting end point 82. The radius of curvature of the corner portion of the sample 80 was set to R = 5 mm. Further, initial cracks were formed in advance at the cutting start point 81 of the end portion of the tempered glass sheet, and no scribe line was formed on the front surface of the tempered glass sheet. The source of the laser light is set to a fiber laser (central band: 1070 nm).

The beam diameter of the laser beam is set to 0.1 mm. The scanning speed of the laser light is set to 5 mm/s in the straight section and 2.5 mm/s in the corner. Here, the corner portion includes a section from the crack generation position 83 of FIG. 24 to the cutting end point 82. Further, in the present embodiment, when the laser beam is scanned and the tempered glass sheet is cut, the laser beam is cooled while the tempered glass sheet is cooled by using the cooling nozzle 28 shown in Fig. 10 . The diameter of the opening of the cooling nozzle used at this time 1 is set to 2 mm, and the distance Gap between the cooling nozzle and the front surface of the tempered glass plate 10 is set to 3 mm. Further, the flow rate of the air flowing in the cooling nozzle was set to 50 L/min.

In the present embodiment, the convexity P1 of the convex portion 89 formed by the unexpected crack 86 extending from the crack generating position 83 toward the cutting line 84 as shown in Fig. 24 is measured, and the amount of the convexity P1 is used to evaluate The quality of the cut sample 80 in the tempered glass sheet is strengthened.

Fig. 25 shows the relationship between the irradiation energy (unit energy) and the convex amount of the laser light per unit irradiation area in the corner portion when the tempered glass sheet is cut. Furthermore, in the present embodiment, the unit energy of the laser light is changed by changing the laser output to 40 W, 50 W, and 75 W, respectively. The unit energy of the laser light is obtained by substituting the laser output (W), the scanning speed (corner portion) of the laser light by 2.5 mm/s, and the beam diameter of 0.1 mm into the above formula 3.

As shown in Fig. 25, in samples No. 1 to No. 3 in which the unit light energy of the laser light was 160 J/mm ² (laser output = 40 W), the convexities were 0.4 mm, 0.5 mm, and 0.45 mm, respectively. In samples No. 4 to No. 6 in which the unit energy of laser light is 200 J/mm ² (laser output = 50 W), the convexities are 0.2 mm, 0.4 mm, and 0.25 mm, respectively. In samples No. 7 and No. 8 in which the unit energy of laser light was 300 J/mm ² (laser output = 75 W), the convexities were 0.15 mm and 0.1 mm, respectively.

The relationship between the unit energy of the laser light and the convexity of the convex portion 89 is shown in FIG. The graph shown in Fig. 26 is a graph obtained by plotting the unit energy and the convex amount of each sample in the table of Fig. 25. As is apparent from the results shown in FIGS. 25 and 26, there is a tendency that the convex amount of the convex portion 89 decreases as the unit energy of the laser light increases.

In other words, the larger the unit energy of the laser light irradiated to the tempered glass sheet, the larger the tensile stress generated in the scanning direction of the laser light is in the interval from the crack generating position 83 to the cutting end point 82. Further, the larger the tensile stress generated in the scanning direction, the more accurately the direction of the crack in the scanning direction can be controlled. Therefore, it is considered that the convex amount of the convex portion 89 is reduced.

<Example 2>

Hereinafter, a second embodiment of the present invention will be described. In Example 2 shown below, a tempered glass sheet having a thickness of 1.1 mm, a surface compressive stress CS of 716 MPa, a thickness DOL of 68.8 μm for each of the front and back layers, and a residual tensile stress CT of 51 MPa was used. .

In the present embodiment, the shape shown in FIG. 23 is cut from the tempered glass sheet 10. Sample 80 (35 mm x 50 mm in the case of this example). The source of the laser light is set to a fiber laser (central band: 1070 nm). The beam diameter of the laser beam is set to 0.1 mm. The scanning speed of the laser light is set to 5 mm/s in the straight section and 1 mm/s in the corner. Here, the corner portion includes a section from the crack generation position 83 of FIG. 24 to the cutting end point 82.

Further, in the present embodiment, an experiment was conducted in which the tempered glass sheet was cooled and the cooling was not performed when the laser light was scanned. When the tempered glass sheet is cooled while scanning the laser light, the cooling nozzle 28 shown in Fig. 10 is used. The diameter of the opening of the cooling nozzle used at this time 1 is set to 1 mm, and the distance Gap between the cooling nozzle and the front surface of the tempered glass plate 10 is set to 2 mm. Further, the flow rate of the air flowing in the cooling nozzle was set to 15 L/min.

In the present embodiment, the convexity P1 of the convex portion 89 shown in Fig. 24 was also measured, and the quality of the sample cut from the tempered glass sheet was evaluated using the amount of the convexity P1.

Fig. 27 shows the relationship between the presence or absence of cooling of the tempered glass sheet and the amount of convexity. Furthermore, in the present embodiment, since the laser output is 80 W, the scanning speed in the corner portion of the laser light is 1 mm/s, and the beam diameter is 0.1 mm, each of the corner portions is obtained according to the above formula 3. The irradiation energy of the laser light per unit irradiation area becomes 800 J/mm ² .

As shown in Fig. 27, in sample No. 9 (without cooling), the convexity was 0.15 mm. On the other hand, in sample No. 10 (with cooling), the amount of convexity was 0.1 mm. Thereby, when the laser beam is scanned while the laser beam is being scanned, the convexity of the convex portion is reduced. The reason is considered to be the distance between the position at which the compressive stress is generated (the laser irradiation region) and the position at which the tensile stress is generated (the rear direction of the scanning direction of the laser light) when the front surface of the tempered glass sheet is cooled. Shortening (refer to FIG. 12), the direction of extension of the crack behind the scanning direction can be more accurately controlled.

The present invention has been described above with reference to the above-described embodiments and examples, but is not limited to the configurations of the above-described embodiments and examples, and it is needless to say that the invention can be completed within the scope of the invention of the technical solution of the scope of the patent application of the present application. Various deformations, corrections, and combinations.

The application is based on the priority of Japanese Patent Application No. 2011-267745, filed on Dec. 7, 2011, and Japanese Patent Application No. 2012-153400, filed on Jul. 9, 2012. All content is incorporated herein.

10‧‧‧Strengthened glass panels

12‧‧‧ positive

13‧‧‧ front layer

14‧‧‧ Back

15‧‧‧Back layer

17‧‧‧Intermediate

20‧‧‧Laser light

22‧‧‧ illuminated area

25‧‧‧ lens

28‧‧‧Cooling nozzle

30‧‧‧ crack

33‧‧‧Compressive stress

35‧‧‧ tensile stress

40‧‧‧ samples

41‧‧‧ cut off the starting point

42‧‧‧ cut end point

43‧‧‧ crack location

44‧‧‧ cut line (side)

45‧‧‧ cut line

46‧‧‧ crack

48‧‧‧ cut the booking line

49‧‧‧ convex

50‧‧‧ samples

52‧‧‧ cut-off point

53‧‧‧ crack location

54‧‧‧ cut line (side)

55‧‧‧ cut line

56‧‧‧ crack

58‧‧‧ cut the booking line

59‧‧‧ convex

60‧‧‧ samples

61‧‧‧ cut off the starting point

62‧‧‧ cut-off point

63‧‧‧ crack location

64‧‧‧ cut line (side)

65‧‧‧ cut line

66‧‧‧ crack

68‧‧‧ cut the booking line

69‧‧‧ convex

71‧‧‧Laser output

72‧‧‧glass maintenance drive

73‧‧‧Control Department

74‧‧‧Control Program Generation Department

82‧‧‧ cut-off point

83‧‧‧ crack location

84‧‧‧ cut line (side)

86‧‧‧ crack

88‧‧‧ cut the booking line

89‧‧‧ convex

11‧‧‧ acute angle

Figure 1 is a cross-sectional view of a tempered glass sheet.

Fig. 2 is a view showing the distribution of residual stress of the tempered glass sheet shown in Fig. 1.

Fig. 3 is a view for explaining a cutting method of a tempered glass sheet.

Figure 4 is a cross-sectional view taken along line A-A of Figure 3.

Figure 5 is a cross-sectional view taken along line B-B of Figure 3.

Fig. 6 is a view for explaining a method of cutting a tempered glass sheet according to an embodiment.

Fig. 7A is a view showing an example of a state in which the tempered glass sheet is cut in a case where the conditions of the laser light irradiated to the tempered glass sheet are inappropriate.

Fig. 7B is a view showing an example of a state in which the tempered glass sheet is cut in a case where the tempered glass sheet cutting method of the embodiment is used.

Fig. 8A shows that the conditions of the laser light irradiated to the tempered glass sheet are inappropriate. In the case of the case, the other example of the cut state of the glass plate is strengthened.

Fig. 8B is a view showing another example of the state in which the tempered glass sheet is cut in the case where the tempered glass sheet cutting method of the embodiment is used.

FIG. 9A is a view showing another example of the cut state of the tempered glass sheet when the conditions of the laser light irradiated to the tempered glass sheet are not appropriate.

Fig. 9B is a view showing another example of the state in which the tempered glass sheet is cut in the case where the tempered glass sheet cutting method of the embodiment is used.

Fig. 10 is a cross-sectional view showing a cooling nozzle used in the method for cutting a tempered glass sheet according to the embodiment.

Fig. 11 is a view for explaining the cooling effect in the method of cutting a tempered glass sheet according to the embodiment.

Fig. 12 is a view for explaining the cooling effect in the method of cutting a tempered glass sheet according to the embodiment.

Fig. 13 is a view for explaining a cutting device for a tempered glass sheet according to an embodiment.

Fig. 14 is a table showing the results of cutting of the tempered glass sheet.

Fig. 15 is a table showing the results of cutting about the non-reinforced glass sheet.

Fig. 16 is a table showing the results of cutting of the tempered glass sheet and the non-reinforced glass sheet.

Fig. 17 is a view for explaining the stress acting on cutting the non-reinforced glass sheet using laser light.

Fig. 18 is a view showing an example of stress acting when the tempered glass sheet is cut by laser light.

Figure 19 is a diagram showing the stress acting on the tempered glass sheet by laser light. A diagram of other examples.

Fig. 20 is a view showing the shape of a line to cut in Reference Example 2.

Fig. 21 is a table showing the laser wavelength λ, the internal strain energy U _CT , the critical irradiation energy Ec, and the conditions for deriving the two with respect to the samples 1 to 12.

Fig. 22A is a graph showing the dependence of the internal strain energy U _CT of the critical irradiation energy Ec shown in the table of Fig. 11 .

Fig. 22B is a graph showing the dependence of the internal strain energy U _{CT on} the critical cutting index Kc shown in the table of Fig. 11.

Fig. 23 is a view for explaining a cutting method of a tempered glass sheet.

Fig. 24 is a view for explaining a cutting method of the tempered glass sheet.

Fig. 25 is a table showing the relationship between the irradiation energy and the convex amount of the laser light per unit irradiation area.

Fig. 26 is a graph showing the relationship between the irradiation energy and the convex amount of the laser light per unit irradiation area.

Fig. 27 is a table showing the relationship between the presence or absence of cooling of the tempered glass sheet and the amount of convexity.

10‧‧‧Strengthened glass panels

40‧‧‧ samples

41‧‧‧ cut off the starting point

42‧‧‧ cut end point

43‧‧‧ crack location

44‧‧‧ cut line (side)

45‧‧‧ cut line

11‧‧‧ acute angle

Claims (15)

A method for cutting a tempered glass sheet, which is directed to strengthening a front layer and a back layer including residual compressive stress and an intermediate layer formed between the front layer and the back layer and having an internal residual tensile stress CT (MPa) The glass plate is cut by moving the irradiation region of the laser light irradiated on the tempered glass sheet, and the thickness of the front layer and the back layer is DOL (μm), and the thickness of the tempered glass sheet is set to t ₁ (μm), when the Young's modulus of the tempered glass sheet is Y (MPa), the strain energy U _CT per unit area based on the internal residual tensile stress CT expressed by the following formula (J/m) ² ) when it is 2.5 J/m ² or more, when the tempered glass sheet is cut so as to be perpendicular to the side surface at the cutting end point of the side surface of the tempered glass sheet, the tempered glass sheet is at a distance from the tempered glass sheet. The irradiation energy of the laser light irradiated per unit irradiation area of the tempered glass sheet is greater than the linear cut of the strong portion in the interval from the specific position at the end of the cutting point to the cutting end point. Laser beam irradiation energy per unit area of the irradiation of the time required for the glass ^{_{sheet, U CT = {CT 2 ×}} (t 1 -2 × DOL)} / (2 × Y). The method for cutting a tempered glass sheet according to claim 1, wherein the effective output of the laser light incident on the tempered glass sheet is Pe (W), and the scanning speed of the laser light is set to v (mm/s). The absorption coefficient of the tempered glass sheet with respect to the laser light is α (mm ^-1 ), the thickness of the tempered glass sheet is t ₂ (mm), and the linear expansion coefficient of the tempered glass sheet is set to α _L (K ^-1 ), when the density of the tempered glass sheet is ρ (g/mm ³ ), and when the specific heat of the tempered glass sheet is c (J/g/K), the cut is expressed by the following formula The breaking index K (N/mm) is set to 150 N/mm or less, and K = Pe / v × exp (-α × t ₂ ) × (Y × α _L ) / (t ₂ × ρ × c). The method for cutting a tempered glass sheet according to claim 1 or 2, wherein the tempered glass sheet and the laser light system have an absorption coefficient of the tempered glass sheet with respect to the laser light of α (mm ^-1 ), When the thickness of the glass plate is t ₂ (mm), the formula of 0 < α × t ₂ ≦ 3.0 is satisfied. The method of cutting a tempered glass sheet according to any one of claims 1 to 3, wherein the specific position at a certain distance from the end of the cutting end is located at a crack originating in an unexpected crack toward the side of the tempered glass sheet. Position is ahead. The method of cutting a tempered glass sheet according to any one of claims 1 to 4, wherein an angle formed by a line segment connecting the scanning position of the laser light to the cutting end point and a side surface of the tempered glass sheet is smaller. The irradiation energy of the laser light irradiated per unit irradiation area of the above tempered glass sheet is larger. The method for cutting a tempered glass sheet according to any one of claims 1 to 5, wherein the irradiation energy of the laser light per unit irradiation area is increased by slowing a moving speed of the irradiation area of the laser light . The method of cutting a tempered glass sheet according to any one of claims 1 to 6, wherein the irradiation energy of the laser light per unit irradiation area is increased by increasing the output of the laser light. The method for cutting a tempered glass sheet according to any one of claims 1 to 7, wherein By making the area of the irradiation region of the laser light small, the irradiation energy of the laser light per unit irradiation area is increased. The method for cutting a tempered glass sheet according to any one of claims 3 to 8, wherein the irradiation energy of the laser light per unit irradiation area is made smaller as the absorption coefficient α of the tempered glass sheet is increased. The method for cutting a tempered glass sheet according to any one of claims 1 to 9, wherein the irradiation energy of the laser light per unit irradiation area is made small as the thermal expansion coefficient of the tempered glass sheet is increased. The method for cutting a tempered glass sheet according to any one of claims 1 to 10, wherein, as the thickness of the tempered glass sheet is increased, the irradiation energy of the laser light per unit irradiation area is increased. The method of cutting a tempered glass sheet according to any one of claims 1 to 11, wherein in the interval, the periphery of the irradiation region of the laser light is further cooled. The method of cutting a tempered glass sheet according to claim 12, wherein the periphery of the irradiation region of the laser light is cooled in at least one of a front surface and a back surface of the tempered glass sheet. A method of cutting a tempered glass sheet according to claim 12 or 13, wherein the periphery of the irradiation region of the laser light is cooled by ejecting gas from the nozzle. A tempered glass sheet cutting device for a tempered glass sheet comprising a front layer and a back layer having residual compressive stress and an intermediate layer formed between the front layer and the back layer and having internal residual tensile stress The irradiation region of the laser light irradiated to the tempered glass sheet is moved and cut, and includes: a glass holding drive portion that holds the tempered glass sheet and moves the tempered glass sheet in a specific direction; a laser output portion that outputs laser light for cutting the tempered glass sheet; and a control portion that is controlled based on a control program The glass holding drive unit and the laser output unit; and a control program generating unit that generates the control program; the control program generating unit generates a control program that faces the cutting end point on the side surface of the tempered glass sheet When the tempered glass sheet is cut so that the side surface becomes an acute angle, the tempered glass is irradiated from a specific position at a predetermined distance from the end of the tempered glass sheet to the end of the cutting end point. The irradiation energy of the laser light per unit irradiation area of the panel is larger than the irradiation energy of the laser light per unit irradiation area required for cutting the tempered glass sheet in a straight line.