JP2013075769A - Method and apparatus for cutting glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably anneal the fused-and-cut end face of a glass plate, when performing fusion/cutting and annealing parallelly to the glass plate, so that the situation causing deformation in the glass plate such as warpage is decreased as much as possible.SOLUTION: There is provided an apparatus 1 for cutting a glass plate, by feeding an assist gas AG and a laser beam from above the glass substrate G along the cutting scheduled line CL of the glass substrate G, and fusing/cutting and separating the glass substrate G with the cutting scheduled line CL as the boundary. The apparatus 1 includes a first laser beam irradiator 2 to conduct irradiation of a first laser beam LB1 for fusion/cutting, and a second laser beam irradiator 3 to conduct irradiation of a second laser beam LB2 for annealing, wherein the second laser beam irradiator 3 irradiates the fused/cut end face Ga1 of the annealing target with the second laser beam LB2 diagonally from upper side through a fused/cut gap S between fused/cut end faces Ga1 and Gb1 formed by fusion/cutting.

Description

  The present invention relates to an improvement of a cutting technique for fusing a glass plate.

  Conventionally, as a method of cutting a glass plate, after forming a scribe line on the surface of the glass plate, a method of cleaving the scribe line by applying a bending stress (cleaving by a bending stress) or an initial crack in the glass plate. After the formation, laser cleaving (cleaving due to thermal stress) is used in which the initial crack is propagated by laser irradiation heat and cleaved.

  However, the cleaving by bending stress has a problem that the generation of fine glass powder cannot be avoided, and the fine glass powder cannot be easily removed even after washing after cutting. Such a problem is particularly a problem in glass substrates for display applications and the like that require high cleanliness. In addition, in the cleaving due to bending stress, the cut end of the glass plate has an angular shape, and defects such as chipping are likely to occur, so it is necessary to chamfer the cut end of the glass plate after cutting. End up.

  On the other hand, with laser cleaving, the glass plate can be cleaved with almost no defects, but it is extremely difficult to avoid contact between the cut end faces of the glass plate when separating the cleaved glass plate. Therefore, at the time of separation, a minute defect may be formed on the cut end surface due to rubbing between the cut end surfaces of the glass plate. Further, even in the laser cleaving, the chamfering process needs to be performed after cutting since the cut end portion of the glass plate has an angular shape, similarly to the cleaving due to the bending stress.

  Laser cutting is attracting attention as a cutting method for coping with such problems.

  Laser fusing is a method of cutting a glass plate while melting and removing a part of the glass substrate by laser irradiation heat. Therefore, in the laser fusing, not only the adhesion of the glass powder can be prevented, but also a predetermined clearance is formed between the fusing end faces (cut end faces) by melting and removing unnecessary glass. With this clearance, it is possible to reliably avoid a situation in which the fusing end surfaces of the glass plates are in contact with each other during separation. Furthermore, since the fusing end face is a smooth fire-making surface formed by melting, damage is unlikely to occur.

  However, even such laser fusing has a problem in practical use. That is, removal of thermal residual strain in the vicinity of the fused end surface of the glass plate.

  In order to remove such thermal residual strain, for example, in Patent Document 1, immediately after fusing by irradiating a glass plate with a laser beam focused on a minute point, it is gradually cooled with a defocused laser beam after fusing. It is disclosed. In addition, the laser beam for slow cooling is irradiated perpendicularly | vertically with respect to the glass plate similarly to the laser beam for fusing.

JP-A-60-251138

However, in the case of Patent Document 1, since the laser beam for slow cooling is incident perpendicularly to the upper surface of the glass plate from directly above the glass plate, the thermal effect of the laser beam is necessarily on the upper surface side of the glass plate. Will be biased. As a result, it is not possible to sufficiently cool the entire cut end surface of the glass plate, and deformation such as warpage may still occur in the glass plate under the influence of thermal residual strain during or after the glass plate is cut. .

  In addition, instead of performing slow cooling in parallel with this as described above, it may be possible to individually cool (anneal) the melted end surface of the glass plate separated after the completion of melting, in this case. The following problems occur. In other words, in recent years, thinning of glass plates, including glass substrates for display applications, has been promoted, and once the glass plate is deformed, such as warpage during fusing, it is damaged during subsequent handling. There is a risk that the glass plate will be damaged at the point of time when deformation occurs. Therefore, considering the recent demand for thin glass plates, it is important to perform slow cooling in parallel with the melting.

  In view of the above circumstances, the present invention, when performing fusing and slow cooling in parallel with the glass plate, surely slowly cools the fusing end surface of the glass plate and causes deformation such as warpage in the glass plate. The technical challenge is to reduce the situation as much as possible.

  The present invention created to solve the above problems is a glass plate cutting method in which a laser beam is irradiated from above along a planned cutting line of a glass plate, and the glass plate is fused and separated with the planned cutting line as a boundary. The laser beam includes a first laser beam for fusing the glass plate and a second laser beam for gradually cooling the fusing end surface of the glass plate, and the second laser beam is formed by the fusing. It is characterized by irradiating diagonally from above with respect to the said melted end surface of the said slow cooling object through the clearance gap between the said melted end surfaces.

  According to such a method, the second laser beam is irradiated obliquely to the fusing end surface to be gradually cooled using the gap between the fusing end surfaces formed by fusing. Therefore, unlike the case of irradiating a slow cooling laser beam perpendicularly to the glass plate, the influence of the irradiation heat of the laser beam is not extremely biased to the upper surface of the glass plate. In other words, since the second laser beam is directly irradiated to a part or all of the fusing end face, the irradiation heat is easily transmitted to the whole fusing end face. Therefore, it is possible to reliably cool the entire fusing end face.

  In the above method, it is preferable to form an intensity distribution in which the thermal energy intensity changes from a fusing execution part to a fusing completion part on the planned cutting line in the irradiation region of the second laser beam. In particular, it is more preferable to form an intensity distribution (temperature gradient) in which the thermal energy intensity decreases from the fusing execution part toward the fusing completion part. Here, the fusing execution part means a part that is actually fusing by the first laser beam, and the fusing completion part means a part that has been fusing by the first laser beam.

  In this way, the influence of the irradiation heat of the second laser beam can be changed from the fusing execution part on the planned cutting line to the fusing completion part, and the slow cooling conditions are appropriately adjusted according to the fusing condition and the like. It becomes possible to do. In particular, when an intensity distribution is formed in which the thermal energy decreases from the fusing execution part toward the fusing completion part, there is an influence of the irradiation heat of the second laser beam from the fusing execution part on the planned cutting line toward the fusing completion part. A gentle temperature gradient is formed that is weakened and gradually decreases in temperature. As a result, the temperature distribution of the melted end surface of the object to be slowly cooled becomes good.

In the above method, as the second laser beam moves from the unfinished portion on the planned cutting line side to the fusing completion portion side or from the fusing completion portion side on the planned cutting line to the uncut portion side. It is preferable to incline so that it may approach the said glass plate as it transfers.

  In this way, the irradiation area of the second laser beam projected on the glass plate becomes long from the unfinished portion side of the fused end surface of the glass plate to the fused portion side. Slow cooling is possible. At this time, when a parallel beam is employed as the second laser beam, the energy distribution in the projection region is point-symmetric from the center. Also, when the focused beam is defocused and irradiated, the thermal energy intensity is gradually reduced from the fusing execution part to the fusing completion part, or the thermal energy is directed from the fusing completion part to the fusing execution part. The strength can be gradually increased. Therefore, when the focused beam is defocused and irradiated as in the former case, it is possible to easily form a temperature gradient in which the temperature gradually decreases from the fusing execution part on the planned cutting line toward the fusing completion part. .

  Here, in the case of defocused irradiation of an inclined focused beam, as shown in FIG. 1, the energy distribution on the beam cross section in the horizontal direction above and below the focused point FP is long. A mode in which energy decreases from one side of the scale irradiation region to the other side is shown, and the gradient of the distribution is reversed in the upper cross section (cross section 1) and the lower cross section (cross section 2). Specifically, in the upper cross section, an aspect in which energy gradually decreases from the front in the horizontal direction toward the rear in the horizontal direction, and in the lower cross section, in an aspect in which energy gradually decreases from the rear in the horizontal direction toward the front in the horizontal direction. Indicates.

  In the above method, it is preferable that a beam shape in a cross section perpendicular to the optical axis of the second laser beam is an elliptical shape.

  In this way, since the second laser beam can be irradiated over a wide range of the glass plate, it is possible to efficiently cool the melted end face. Further, as described above, when the second laser beam is inclined, the intensity gradient of the thermal energy intensity can be made gentle by increasing the entire length of the irradiation region without increasing the inclination.

  In the above method, the irradiation region of the second laser beam may be formed so as to overlap the irradiation region of the first laser beam so as to straddle the front and rear of the irradiation region of the first laser beam. The “overlapping” state here is a state in which the irradiation region of the second laser beam and the irradiation region of the first laser beam have an overlapping portion, and the irradiation region of the second laser beam is the first laser beam. This means that it is protruding before and after the irradiation region (before and after the fusing direction). That is, in the width direction orthogonal to the fusing progress direction, a part of the irradiation region of the first laser beam may or may not protrude from the irradiation region of the second laser beam.

  In this way, prior to the first laser beam, the glass plate can be preheated in a part of the irradiation region of the second laser beam. Therefore, it is possible to prevent the temperature of the glass plate from rapidly rising when the glass plate is melted by the first laser beam, and to reduce the occurrence of thermal residual strain.

  In the above method, the first laser beam and the second laser beam may be formed by diverging laser beams emitted from the same light source.

  In this way, since the light sources can be combined into one, space saving can be achieved. In this case, it is preferable to adjust the respective outputs of the first laser beam and the second laser beam to optimum values. As an output adjustment method, for example, the transmittance (reflectance) of a half mirror or the like used for separating the first laser beam and the second laser beam is adjusted, or the light is reduced by an ND filter or the like on the optical path. It is possible to arrange these optical components.

  In the above method, the first laser beam and the second laser beam may be emitted from different light sources.

  In this way, since the light source of the first laser beam and the light source of the second laser beam are independent from each other, the output of one laser beam can be easily adjusted without affecting the other laser beam. There is an advantage that you can.

  In order to solve the above-mentioned problems, the present invention provides a glass plate cutting device that irradiates a laser beam from above along a planned cutting line of a glass plate and melts and separates the glass plate with the planned cutting line as a boundary. A first laser irradiator for irradiating a first laser beam for fusing the glass plate, and a second laser irradiator for irradiating a second laser beam for gradually cooling the fusing end surface of the glass plate, The second laser irradiator irradiates the second laser beam obliquely from above with respect to the fusing end surface of the slow cooling target through a gap between the fusing end surfaces formed by the fusing. It is done.

  According to such a configuration, it is possible to enjoy the same operational effects as those of the corresponding method invention described above. The first laser irradiator and the second laser irradiator may be separate from each other, or the first laser irradiator may also serve as the second laser irradiator.

  According to the present invention as described above, since the entire fusing end surface of the glass plate can be surely gradually cooled, it is possible to reduce as much as possible the situation in which deformation such as warpage occurs in the glass plate. .

It is a figure for demonstrating the effect | action of the glass plate cutting method which concerns on this invention. (A) is a vertical front view which shows the glass plate cutting device which concerns on this embodiment, (b) is a top view which shows the irradiation area | region of the laser beam. (A) And (b) is a top view which shows the modification of the irradiation area | region of the laser beam in the glass plate cutting device concerning this embodiment. It is a perspective view which shows the irradiation state of the 2nd laser beam in the glass plate cutting device which concerns on this embodiment. It is a perspective view which shows the irradiation state of the 2nd laser beam in the glass plate cutting device which concerns on this embodiment. It is a conceptual diagram for demonstrating the irradiation state at the time of using a parallel beam as a 2nd laser beam in the glass plate cutting device which concerns on this embodiment. It is a conceptual diagram for demonstrating the irradiation state at the time of using a focused beam as a 2nd laser beam in the glass plate cutting device which concerns on this embodiment, and defocusing the focused beam. It is a perspective view which shows the modification of the irradiation aspect of the laser beam in the glass plate cutting device which concerns on this embodiment. It is a perspective view which shows the modification of the irradiation aspect of the laser beam in the glass plate cutting device which concerns on this embodiment. It is a vertical front view which shows the modification of the glass substrate used as the cutting object of the glass plate cutting device which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the glass plate is a glass substrate for a flat panel display having a thickness of 500 μm or less, but it is of course not limited thereto. For example, the present invention can be applied to thin glass sheets in various fields such as solar cells, organic EL, touch panels, and digital signage, and laminates for various uses laminated with organic resins. In addition, it is preferable that the thickness of a glass plate is 300 micrometers or less.

  As shown in FIGS. 2 (a) and 2 (b), the glass sheet cutting apparatus 1 according to one embodiment of the present invention is configured so that the glass substrate G in a flat position is not separated from the product portion Ga with the planned cutting line CL as a boundary. The product part Gb is fused and separated, and includes a first laser irradiator 2, a second laser irradiator 3, and a gas injection nozzle 4.

  The first laser irradiator 2 irradiates the first laser beam LB1 for fusing substantially vertically from directly above the planned cutting line CL of the glass substrate G. By this first laser beam LB1, a first irradiation region SP1 serving as a fusing execution part is formed in a part of the planned cutting line CL of the glass substrate G. In this embodiment, the first irradiation region SP1 is moved by moving the glass substrate G in the direction of arrow A (hereinafter, referred to as a conveyance direction) by a conveyance unit (not illustrated) (for example, a conveyance belt that sucks and holds the glass substrate G). Scanning is performed along the planned cutting line CL, and the glass substrate G is continuously melted and separated. In addition, not only the case where only the glass substrate G is moved in this way, the processing unit including the first laser irradiator 2, the second laser irradiator 3, and the gas injection nozzle 4 and the glass substrate G are relatively If there is movement, the glass substrate G can be melted. For example, the processing unit may be moved while the glass substrate G is stationary.

  The second laser irradiator 3 is connected to the product part Ga from the upper side of the non-product part Gb through the fusing gap S between the fusing end faces Ga1 and Gb1 formed by fusing the glass substrate G with the first laser beam LB1. The second laser beam LB2 for slow cooling (annealing) is obliquely irradiated to the fusing end face Ga1 on the side to be. By the second laser beam LB2, a second irradiation region SP2 serving as a slow cooling execution unit is formed in a part of the planned cutting line CL of the glass substrate G. The second irradiation area SP2 is a long and narrow area (in the illustrated example, an oval shape) along the planned cutting line CL, and is melted on the planned cutting line CL at a distance from the first irradiation area SP1. It is formed in the completion part R1. In this embodiment, by moving the glass substrate G as described above, the second irradiation region SP2 is scanned along the planned cutting line CL, and the melted end face Ga1 on the side that becomes the product part Ga is continuously gradually cooled. To do. In addition, as shown to Fig.3 (a), 2nd irradiation area | region SP2 may be in contact with 1st irradiation area | region SP1. Further, as shown in FIG. 3B, the second irradiation region SP2 may be formed so as to overlap the first irradiation region SP1 so as to straddle before and after the transport direction of the first irradiation region SP1. In the latter case, since a part of the second irradiation region SP2 is formed in the uncut portion R2 of the glass substrate G, the glass substrate G is preheated immediately before the cutting.

The gas injection nozzle 4 injects the assist gas AG from above to the first irradiation region SP1 in order to blow away the molten foreign matter generated in the first irradiation region SP1. Specifically, the gas injection nozzle 4 is arranged at an upper position on the side of the glass substrate G that becomes the product part Ga, and the assist gas AG is directed from the upper position on the side that becomes the product part Ga toward the first irradiation region SP1. It is injected at an angle. Thereby, the melted foreign matter is blown off to the non-product part Gb side by the assist gas AG, and the situation in which the melted foreign matter adheres to the fusing end surface Ga1 of the product part Ga is suppressed. Here, “molten foreign matter” means foreign matters such as dross generated when the glass substrate G is melted, and includes both those in a molten state and those in a solidified state. As the assist gas AG, for example, a gas such as oxygen (or air), water vapor, carbon dioxide, nitrogen, and argon is used alone or in a mixed state. Further, the assist gas AG may be injected as hot air. The arrangement position of the gas injection nozzle 4 in the upper space of the glass substrate G is not particularly limited. For example, the gas injection nozzle 4 is arranged immediately above the planned cutting line CL, and the first laser beam LB1 and the glass substrate G. Thus, the assist gas AG may be injected substantially vertically.
Further, the gas injection nozzle 4 may be disposed in the lower space of the glass substrate G so that the molten foreign matter is blown from the lower side of the glass substrate G. These assist gases AG are for efficient fusing, but may be omitted as appropriate.

As shown in FIG. 4, the second laser irradiator 3 is disposed at an upper position on the side that becomes the non-product part Gb of the unfinished part R <b> 2. The second laser beam LB2 emitted from the second laser irradiator 3 is inclined so as to approach the glass substrate G as it moves from the incomplete fusing part R2 side to the fusing completion part R1 side. The second laser beam LB2 may be inclined so as to approach the glass substrate G as it moves from the fusing completion part R1 side to the fusing incomplete part R2 side. That is, the second laser beam LB2 has an azimuth angle θ and a polar angle φ as shown in the drawing. Therefore, as shown in FIG. 5, the second irradiation region SP2 projected onto the glass substrate is elongated from the first irradiation region SP1 serving as the fusing execution portion to the fusing completion portion R1, and has an elliptical shape. The direction of the major axis of the elliptical shape is illustrated in parallel with the planned cutting line CL in FIG. 2B, but varies depending on the magnitude of the azimuth angle θ. If the range is 0 <θ <π / 2 and π / 2 <θ <π, the thermal energy of the second laser beam LB2 in the second irradiation region SP2 has a component in the direction along the planned cutting line CL. The intensity has a gradual change from the first irradiation region SP1 side to the fusing completion portion R1 side. Therefore, an intensity gradient is formed in which the thermal energy intensity gradually changes from the first irradiation region SP1 on the planned cutting line CL to the fusing completion portion R1 side. Here, when a parallel beam is adopted as the second laser beam LB2, the effect of irradiation is the same regardless of the range of 0 <θ <π / 2 and π / 2 <θ <π with respect to the azimuth angle θ. When using a focused beam and irradiating with defocus, there is an appropriate range of azimuth angle θ. That is, when the glass substrate G is subjected to defocus irradiation at a position below the condensing point (see cross section 2 in FIG. 1), 0 <θ <π / 2 is an appropriate range, and conversely, it is smaller than the condensing point. When defocus irradiation is performed on the glass substrate G at the upper position (see cross section 1 in FIG. 1), π / 2 <
θ <π is an appropriate range. Of course, when θ = π / 2, the second laser beam LB2 having a cross section perpendicular to the optical axis preliminarily shaped into an elliptical shape so that the direction of the major axis is along the planned cutting line CL is the side that becomes the product portion Ga. You may make it irradiate to fusing end surface Ga1. Examples of a method of previously shaping the cross section orthogonal to the optical axis of the laser beam into an elliptical shape include using an optical component such as a cylindrical lens, a slit-shaped light shielding mask, or the like.

Here, the azimuth angle θ and polar angle φ of the second laser beam LB2 are preferably in the following ranges. That is, the azimuth angle θ is preferably in the range of 0 <θ <π / 2 and π / 2 <θ <π. On the other hand, with respect to the polar angle φ, as shown in FIG. 6, when a parallel beam is adopted as the second laser beam LB2, the beam diameter of the second laser beam LB2 is w ₂ , the thickness of the glass substrate G is t, and the irradiation is performed. If the position adjustment amount is d, 0 <φ <cos ⁻¹ [(t + w ₂ ) / {2 (s + t
+ D)}] is preferably satisfied. In addition, as shown in FIG. 7, the polar angle φ employs a focused beam as the second laser beam LB2, and when the focused laser beam is defocused and irradiated, the second laser beam LB2 is separated from the non-product part Gb. The beam diameter at the contact point in contact is w ₂ ,
Satisfy the range of 0 <φ <cos ⁻¹ [(t cos α + w ₂ ) / {2 (s + t + d)}] where α is the condensing angle, t is the thickness of the glass substrate G, and d is the adjustment amount of the irradiation position. Is preferred.
That is, the polar angle φ is preferably set in an angle range that does not interfere with the vicinity of the melted end face Gb1 of the non-product part Gb that is close to and faces the melted end face Ga1 of the product part Ga. The irradiation position of the second laser beam LB2 is preferably adjusted according to the position of the tensile stress generated in the vicinity of the melt end face Ga1 of the product part Ga before the slow cooling, and the adjustment amount d is, for example, −t / It is adjusted in the range of 2 ≦ d ≦ 2.5t.

  If the second laser beam LB2 is shaped so that the cross section orthogonal to the optical axis is elliptical, the entire length is long and the gradient of the energy distribution is increased without increasing the tilt angle (polar angle φ). A gentle second irradiation region SP2 can be formed.

  Next, operation | movement of the glass cutting device 1 which concerns on this embodiment comprised as mentioned above is demonstrated easily.

  First, as shown in FIGS. 2A and 2B, the first laser beam LB1 is applied to the glass substrate G from the first laser irradiator 2 while the glass substrate G is being conveyed. Thereby, the glass substrate G is melted. At this time, the assist gas AG is injected from the gas injection nozzle 4 to the first irradiation region SP1 of the first laser beam LB1, and the molten foreign matter is blown off from the first irradiation region SP1.

  At the same time, the glass substrate G is irradiated with the second laser beam LB2 from the second laser irradiator 3. The second laser beam LB2 is inclined obliquely from above with respect to the fusing end surface Ga1 on the side to be the product part Ga through a fusing gap S between the fusing end surfaces Ga1 and Gb1 formed by irradiation of the first laser beam LB1. Irradiate. Thereby, the melt end face Ga1 is gradually cooled.

  In this way, the influence of the irradiation heat of the second laser beam LB2 is not extremely biased to the upper surface of the glass substrate G as in the case where the second laser beam LB2 is irradiated perpendicularly to the upper surface of the glass substrate G. . In other words, since the second laser beam LB2 is directly irradiated to a part or the whole of the fusing end surface Ga1, the irradiation heat is easily transmitted to the entire fusing end surface Ga. Therefore, even if the glass substrate is a thin plate having a thickness of 500 μm or less, it is possible to avoid the problem that the residual strain is efficiently removed and deformation such as warpage occurs.

  Here, the melting of the glass substrate G is completed when the first laser beam LB1 starts melting from the upper surface side of the glass substrate G, and a cutting groove formed by the melting penetrates downward. For this reason, the closer the fusing end surface Ga1 is to the upper surface, the stronger the influence of irradiation heat supplied at the time of fusing, and the thermal residual strain of the fusing end surface Ga1 is considered to be relatively large on the upper surface side. . Therefore, in order to remove the residual strain of the fusing end surface Ga1, it is preferable to supply a larger amount of heat to the upper surface side of the fusing end surface Ga1 and perform a slow cooling treatment. Therefore, as illustrated in FIGS. 6 and 7, it is preferable that the second laser beam LB2 is directly applied to the upper part (for example, the upper half region) of the fusing end face Ga1.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

  In said embodiment, the case where the 1st laser irradiation device 2 is arrange | positioned just above the cutting projected line CL of the glass substrate G, and the 2nd laser irradiation device 3 is arrange | positioned above the non-product part Gb of the glass substrate G is used. Although demonstrated, the arrangement | positioning aspect of the 1st laser irradiation device 2 or the 2nd laser irradiation device 3 is not limited to this. For example, as shown in FIG. 8, the first laser irradiator 2 and the second laser irradiator 3 are arranged above the product portion Ga, and the first laser beam LB1 is formed by optical components such as mirrors 5 and 6. The second laser beam LB2 may be guided.

  In the above embodiment, the first laser irradiator 2 and the second laser irradiator 3 are configured by separate light sources. However, as shown in FIG. 9, the first laser irradiator 2 is a second laser. The irradiator 3 may also be used. That is, the laser beam LB emitted from the first laser irradiator 2 may be branched into the first laser beam LB1 and the second laser beam LB2 by an optical component such as the half mirror 7. In this case, the second laser beam LB2 is irradiated on the glass substrate G after being attenuated by an ND filter or the like on the optical path.

In addition, when the glass substrate G is formed by the overflow Dundraw method or the like, the thickness of both end portions in the width direction of the glass substrate G is relatively larger than the thickness of the center portion in the width direction of the glass substrate G as shown in FIG. It becomes thick. And the width direction center part is made into the product part Ga, and the width direction both ends are made into the non-product part (it calls an ear | edge part) Gb. The cutting method and the cutting apparatus according to the present invention may be applied to the removal of the ear portion of the glass substrate G.

  In the above-described embodiment, the case where the glass substrate G is fused and separated into the product part Ga and the non-product part Gb has been described. However, the glass substrate G may be applied to the case where both of the fused parts are used as the product part.

A comparison test was conducted to demonstrate the usefulness of the present invention. In this comparison test, a non-alkali glass sample and a soda glass sample were prepared for each of the example and the comparative example, each sample was melted, (1) confirmation of the presence or absence of residual strain on the melted end face, (2) Confirmation of the presence or absence of breakage by a flaw test on the fusing end face, and (3) confirmation of the presence or absence of warpage of each sample after fusing. Details are as follows.
(1) Residual strain The presence or absence of residual strain on the fusing end face was confirmed by observing the fusing end face of each sample using the Senarmon method or sensitive color method, which is an optical strain measurement.
(2) Scratch test A flaw test on the fusing end face was confirmed by whether or not the fusing end face of each sample was scratched with # 1000 sand paper, left for 1000 hours, and whether or not it self-destructed.
(3) Warpage Each sample after fusing was placed on a surface plate and checked for warpage. Here, the warpage is confirmed when the back side of each sample is down and when the back side is down, and in each case, when a floating part of 0.3 mm from the surface plate exists on the peripheral part of the sample Was evaluated as “Yes”.

The results of the comparison test as described above are shown in Tables 1 and 2. In the table, θ and φ are based on FIG. 4, and w ₂ , s, and d are based on FIGS. 6 and 7. The energy intensity [W] of the laser beam in the table is actually a value on the glass substrate surface.

  According to Table 1 above, in Comparative Examples 1 and 2 in which the second laser beam for slow cooling is vertically incident on the glass substrate, there are defects in the residual strain, the scratch test, and the warp. I can confirm that. On the other hand, in Examples 1-6 in which the second laser beam for slow cooling was made incident on the glass substrate while being inclined, good results were obtained for all of the residual strain, the scratch test, and the warp. I can recognize that.

DESCRIPTION OF SYMBOLS 1 Glass plate cutting device 2 1st laser irradiation machine 3 2nd laser irradiation machine 4 Gas injection nozzle AG Assist gas CL Planned cutting line G Glass substrate Ga Product part Ga1 Fusing end surface Gb Non-product part LB1 1st laser beam LB2 2nd laser Beam SP1 first irradiation area (melting execution part)
SP2 2nd irradiation area (slow cooling execution part)
S Fusing gap R1 Fusing completion part R2 Fusing incomplete part θ Azimuth angle of second laser beam φ Polar angle of second laser beam

Claims (8)

In the glass plate cutting method of irradiating a laser beam from above along the cutting line of the glass plate and fusing and separating the glass plate with the cutting line as a boundary,
The laser beam includes a first laser beam for fusing the glass plate and a second laser beam for gradually cooling the fusing end surface of the glass plate;
The glass plate cutting method characterized in that the second laser beam is irradiated obliquely from above on the fusing end surface of the slow cooling target through a gap between the fusing end surfaces formed by the fusing. .   2. The glass plate cutting according to claim 1, wherein, in the irradiation region of the second laser beam, an intensity distribution in which thermal energy intensity changes from a fusing execution part to a fusing completion part on the planned cutting line is formed. Method.   As the second laser beam moves from the incomplete cutting portion side on the planned cutting line to the fusing completion portion side or from the fusing completion portion side on the planned cutting line to the fusing incomplete portion side The glass plate cutting method according to claim 1, wherein the glass plate is inclined so as to approach the glass plate.   The glass plate cutting method according to any one of claims 1 to 3, wherein a beam shape in a cross section orthogonal to the optical axis of the second laser beam is an elliptical shape.   The irradiation region of the second laser beam is formed so as to overlap the irradiation region of the first laser beam so as to straddle the front and rear of the irradiation region of the first laser beam. The glass plate cutting method according to any one of 4.   The glass plate cutting according to any one of claims 1 to 5, wherein the first laser beam and the second laser beam are formed by diverging laser beams emitted from the same light source. Method.   The glass plate cutting method according to any one of claims 1 to 5, wherein the first laser beam and the second laser beam are emitted from different light sources. In a glass plate cutting apparatus that irradiates a laser beam from above along the planned cutting line of the glass plate and melts and separates the glass plate with the planned cutting line as a boundary,
A first laser irradiator for irradiating a first laser beam for fusing the glass plate; and a second laser irradiator for irradiating a second laser beam for gradually cooling the fusing end surface of the glass plate, A two-laser irradiator irradiates a second laser beam obliquely from above with respect to the fusing end face of the slow cooling target through a gap between the fusing end faces formed by the fusing. Board cutting device.