JP2013006706A - Cleaving method and apparatus for glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaving method and apparatus which can reliably make a flaw serving as a first crack in tempered glass, reliably form a scribe, and enables a break to run straight.SOLUTION: Laser beams 53 having a wavelength in a range from a visible region to an ultraviolet region are condensed along the cleaving scheduled line 12 of a glass substrate 11 in such a way that the focal position is located in the surface of an interior position along the cleaving scheduled line from the end of the glass substrate 11, to form a surface crack 17 which is a starting point of scribing. The focal point of the laser beams 53 is set within the glass substrate 11, and the laser beams 53 are moved relatively to the glass substrate 11 to form an internal crack 16 extending from the surface crack 17 to the end face of the glass substrate 11 passing through the inside of the glass substrate 11.

Description

The present invention is applied to a glass for flat panel displays used in smartphones, tablet terminals, notebook computers, touch table screens, television screens, etc., in particular aluminosilicate glass or float glass having a chemically strengthened glass surface, and then subjected to air cooling. The present invention relates to a glass substrate cleaving method and cleaving apparatus for cleaving tempered tempered glass or thick glass having a thickness of 3 mm or more (hereinafter collectively referred to as tempered glass).

Recently, in the glass cleaving, a thermal stress scribing method (hereinafter abbreviated as laser scribing) by laser beam irradiation has been used in place of the mechanical method using a diamond chip that has been used for the past century.

  According to laser scribing, defects inherent in the mechanical method, that is, a decrease in glass strength due to the occurrence of microcracks, contamination due to the occurrence of cullet at the time of cleaving, the presence of a lower limit value of the applied plate thickness, and the like can be eliminated.

When laser scribing glass, it is necessary to form a crack called an initial crack near the edge of the glass. Conventionally, the formation of this initial crack is generally a so-called mechanical initial crack formation method in which scratches are formed with a cutter using diamond. In this method, scratches are formed by scratching the surface of the glass with a blade such as a diamond cutter, so that scratches are formed only on the surface. There is no problem with the conventional mechanical method in a glass having low hardness such as soda glass.

On the other hand, in recent years, tempered glass subjected to chemical treatment to increase the hardness of the glass surface has been utilized as glass for flat panel displays such as smartphones, tablet terminals, notebook computers, touch table screens and television screens.

Since such a tempered glass has a hard surface, it is difficult to scratch with a diamond cutter or the like, and it is difficult to stably scratch the surface. In addition, in order to ensure the stability of the laser scribe, it is necessary to form a number of stable initial cracks, but because the surface of the tempered glass is hard, the depth of the scratches is not stable and strengthened. In some cases, the thickness of the layer cannot be broken through. Furthermore, when the cutter is pressed with an excessively strong force, the glass itself may break, not only on the surface, particularly in the case of thin glass.

Thus, in order to form a stable initial crack in the tempered glass, it is necessary to use trial and error to optimally set the processing parameters such as the stroke of the diamond cutter, the pressing force, the scratching distance on the glass, Finding the optimal range was also difficult.

Therefore, a method using a pulse oscillation type laser instead of forming scratches by scratching the surface of glass with a blade such as a diamond cutter as an initial crack forming means has been studied.
For example, a first laser beam having a wavelength from the visible region to the near infrared region is condensed near the surface of the glass to form an initial crack, and a second laser beam such as a carbon dioxide laser beam is irradiated to the initial crack and its periphery. Then, while the irradiation position of the second laser beam is moved, the cooling medium is sprayed on the region irradiated with the second laser beam to cool the glass, and the glass breakage crack is developed from the initial crack as a starting point. In the laser processing method (see Patent Document 1) that cleaves the brittle material substrate and the method that cleaves the brittle material substrate using a laser beam having a high transmittance with respect to the brittle material substrate, it is possible to suppress the leading-edge phenomenon in which cracks occur in an unpredictable direction from the trigger crack Therefore, the substrate side of one surface of the brittle material substrate using CO ₂ laser or YAG laser A method of forming a trigger crack on the inner side than the end (see Patent Document 2) has been proposed.

JP 2007-260749 A Japanese Patent Publication No. 2010-89144

In the laser processing method according to Patent Document 1, an initial crack is formed by condensing a first laser beam having a wavelength from the visible region to the near-infrared region, but the height of the focal position of the first laser beam can be adjusted. It is severe and there is a problem in operability. In addition, Patent Document 1 describes the depth from the vicinity of the surface of the glass, but there is no description that laser scribing was performed by a combination of heating and cooling, starting from an initial crack actually formed by the technique. . Therefore, even if this initial crack is formed, there is no description of what kind of technique is required when laser scribing is actually performed.

In fact, when the glass substrate is a tempered glass, the stronger the chemically treated glass, the harder it is to break, and even when the glass is thick, it becomes difficult because a large force is required for the break. There is no mention of how to solve this problem.
In addition, when the glass is tempered strongly or when the glass is thick, a large bending stress is required for breaking, and breakage is difficult, but no solution to this problem is described.

In the laser processing method according to Patent Document 2, by inserting an initial crack inside rather than an end of glass, a scribe groove is formed from the crack toward the front, that is, toward the inside of the glass. There is a description that scribe stability can be expected when an initial crack is formed inside.

However, when a crack is formed inside the glass, the crack or scribe groove is not formed at the edge of the glass in the rearward direction from the crack. There is a possibility that the surface becomes bent, and linearity cannot be obtained at the time of break. Thus, in the case where the initial crack is formed inside the brittle material, there is a problem that the fractured surface after the break is deviated from the planned cutting line and is curved. No solution is presented.
Similarly to Patent Document 1, there is no description of a solution to the problem that breakage is difficult because a large bending stress is required to break when the glass is strong or thick.

The present invention solves these problems of the prior art, and in a glass substrate, particularly tempered glass, it is possible to surely introduce a scratch that becomes an initial crack, and a scribe is reliably formed, and breakage is facilitated, Moreover, it is an object of the present invention to provide a cleaving method and a cleaving apparatus that can break even a tempered glass so that the break runs straight.

In order to achieve the above object, the present invention heats the glass substrate with the first laser beam for heating along the planned cutting line of the glass substrate, and the heating position of the glass substrate with the first laser beam along the planned cutting line. The glass substrate is cleaved by relatively moving the scribe grooves in the glass substrate, and the focal point of the second laser beam having a wavelength from the visible region to the ultraviolet region is cleaved from the end of the glass substrate. Condensing light so that it is located on the inner surface along the planned line to form a surface crack that becomes the initial crack that is the starting point of the scribe, and the focus of the second laser beam is set inside the glass substrate Then, the second laser beam is moved relative to the glass substrate to form an internal crack extending from the surface crack through the inside of the glass substrate and extending to the end surface of the glass substrate.
According to the above configuration, a glass substrate, particularly a glass substrate in which the glass substrate is formed of tempered glass, can be surely provided with a scratch that becomes an initial crack, so that a scribe groove is reliably formed and a break is generated in the breaking step. In addition, the break can run straight over the entire planned cutting line of the glass substrate, and even tempered glass that is difficult to break can be cut reliably.

In addition, the scribe groove is formed by developing a scratch that becomes the initial crack by starting with a scratch that becomes the initial crack by spraying a cooling medium onto the region heated by the first laser beam and cooling it.
According to the said structure, the scribe groove | channel of sufficient depth can be reliably formed in tempered glass.

The second laser beam is preferably a laser beam in a wavelength region that shows green in the visible region.
According to the said structure, the surface crack used as the first crack in tempered glass and the internal crack inside glass can be formed easily and reliably.

Further, the internal crack is formed by a linear portion extending from the end surface of the glass substrate toward the inside of the glass substrate and a curved portion extending from the inside of the glass substrate toward the surface crack on the surface of the glass substrate.
According to the above configuration, the internal crack is formed to extend in the depth direction of the glass substrate, and this internal crack guides the break. Therefore, the linearity of the break in the vicinity of the end of the glass substrate can be improved. .

Further, the internal crack extends from the end surface of the glass substrate to the inside of the glass substrate, and is formed by a linear portion that reaches the surface of the glass substrate.
According to the above configuration, the internal crack is formed to extend in the depth direction of the glass substrate, and this internal crack guides the break. Therefore, the linearity of the break in the vicinity of the end of the glass substrate can be improved. .

Moreover, the internal crack was formed by the 1st waveform part extended toward the inside of a glass substrate from the end surface of a glass substrate, and the 2nd waveform part extended toward the surface crack in the surface of a glass substrate from the inside of a glass substrate. Is.
According to the above configuration, the internal crack is formed to extend in the depth direction of the glass substrate, and this internal crack guides the break. Therefore, the linearity of the break in the vicinity of the end of the glass substrate can be improved. .

According to the present invention, since the scratch which becomes the initial crack of the scribe is performed by the laser beam having a wavelength from the visible region to the ultraviolet region, the crack can be formed at the focal position of the beam, and is not limited to the glass surface. Can be scratched. Therefore, it is condensed on the surface of the inner position from the end of the tempered glass to form a scratch that becomes the initial crack of the scribe, and the initial crack from the position in the thickness direction of the tempered glass at the end of the tempered glass. Internal cracks can be formed that extend into the scratch.

As a result, a scribe groove is formed along the planned cutting line from the scratch that becomes the initial crack, and the stability of the scribe is improved. In addition, since an internal crack extending to the end of the glass is formed in the thickness direction of the tempered glass behind the scratch that becomes the initial crack at the time of the break, the cleaving by the break is performed along the internal crack, A split section having high linearity can be formed along the planned cutting line.

Further, when forming the internal crack, the internal crack can be freely formed so that the height position is different in the cross-sectional direction of the glass by moving the focal position of the laser beam up and down, so the thickness of the tempered glass is thick. Even in this case, it can be easily broken.

Further, by moving the focal position of the laser beam up and down, even if a positional deviation due to the accuracy of the machine occurs, an initial crack can be reliably formed on the surface of the glass.

Schematic of a brittle material cleaving apparatus according to Embodiment 1 of the present invention Schematic which shows the whole structure of the initial crack formation apparatus part of the brittle material cleaving apparatus which concerns on Example 1 of this invention. The perspective view which showed typically the embodiment in the middle of cleaving a glass substrate using the brittle material cleaving apparatus which concerns on Example 1 of this invention. Sectional side view explaining the embodiment when the initial crack is formed in the glass substrate in the brittle material cleaving method which concerns on Example 1 of this invention The perspective view which showed typically the other embodiment in the middle of cleaving in the brittle material cleaving method which concerns on Example 1 of this invention. Sectional side view explaining the embodiment when the initial crack is formed in the glass substrate in the brittle material cleaving method which concerns on Example 2 of this invention Sectional side view explaining the embodiment when the initial crack is formed in the glass substrate in the brittle material cleaving method which concerns on Example 3 of this invention Sectional photograph of a glass substrate sample having a thickness of 1.1 mm divided by the brittle material cleaving method according to Example 2 of the present invention Sectional photograph of a glass substrate sample having a thickness of 1.1 mm divided by the brittle material cleaving method according to Example 3 of the present invention An enlarged cross-sectional photograph of the vicinity of the surface of a 1.1 mm thick glass substrate sample divided by the brittle material cleaving method according to Example 3 of the present invention

In the present invention, a laser beam having a wavelength in the visible region to the ultraviolet region is condensed so that the focal position is located on the surface of the inner position along the planned cutting line from the edge of the glass substrate, and the scribe origin The surface crack that is the initial crack is formed, and the focal point of the laser beam is set inside the glass substrate, and the laser beam is moved relative to the glass substrate, so that the inside of the glass substrate is separated from the surface crack. An internal crack extending through the end surface of the glass substrate is formed.
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. In the following description, a glass substrate will be described as an example of the brittle material.

FIG. 1 is a conceptual diagram showing the overall configuration of a cleaving apparatus for carrying out the tempered glass cleaving method according to the present invention. The glass substrate 11 is placed on a movable table 32, and the movable table 32 is moved in the XY plane by an XY driving device. In the figure, only the servo motor 33 for driving the Y axis, which is the moving direction of the glass, and the shaft axis are shown, and the X axis driving system is not shown.

A CO ₂ laser 25 is used as a laser oscillator for heating the glass substrate 11. As the CO ₂ laser 25, for example, a gas-sealing type having a maximum output of 100 W is used. When the surface reinforcing layer of the glass substrate 11 is thick or the glass substrate 11 is thick such as 3 mm or more, it is often difficult to break, so a laser oscillator having a maximum output of 100 W or more may be used. preferable.

When the laser beam 26 having a beam diameter of φ4 mm passes through the beam expander 27, the beam diameter is enlarged by about four times to become a beam having a φ16 mm. The expanded beam is reflected vertically downward by the reflecting mirror 28, passes through the beam shaping means 80, is shaped from a circular beam shape into an elongated beam shape, and is irradiated on the glass substrate 11 in an elongated beam shape. .

As the beam shaping means 80, an optical component such as a diffractive optical element (DOE) or a cylindrical lens can be specifically used. In this embodiment, a rectangular aperture and a cylindrical lens are used in combination.

A cooling device 30 is installed behind the position where the laser beam 26 is irradiated onto the glass substrate 11. As the cooling device 30, a two-tube type cooling nozzle is used, and water is injected from the inner cylindrical tube and air is injected from the outer cylindrical tube. A cooling point is formed on the glass substrate 11 by spraying the mixed medium of water and air toward the glass.

An initial crack forming device 50 is provided in front of the irradiation position of the laser beam on the glass substrate 11. The initial crack forming apparatus 50 includes a pulse laser oscillator 51 that generates a pulsed laser beam having a wavelength from the visible region to the ultraviolet region, and a focusing lens system 52 that converges the laser beam oscillated from the pulse laser oscillator 51. The laser beam 53 converged by the focusing lens system 52 is applied to the glass substrate 11.

As a laser beam having a wavelength from the visible region to the ultraviolet region oscillated by the pulse laser oscillator 51, for example, a green laser that oscillates green light in the wavelength region of 510 to 540 nm, an ultraviolet laser that oscillates ultraviolet light in the wavelength of 355 nm, or the like is used. Is done. In any case, it is preferable that the peak output is large. In this embodiment, a pulsed Nd: YAG laser with a built-in Q switch having a wavelength of 532 nm is used.

FIG. 2 shows the overall configuration of the initial crack forming apparatus 50. The optical path of the laser beam from the pulse laser oscillator 51 is adjusted by the reflecting mirrors 54, 55, shaped into a circular beam having an enlarged diameter by the beam expander 56, incident on the focusing lens system 52, and converged by the focusing lens system 52. The laser beam 53 is irradiated onto the glass substrate 11. The focusing lens system 52 can be moved in the vertical direction, that is, the vertical direction with respect to the surface of the glass substrate 11 by the Z-axis actuator 57, and the focal position 65 of the laser beam 53 with respect to the glass substrate 11 can be adjusted. The position of the focal position 65 is a position determined by the value of the focal length f determined by the focusing lens system 52. The vertical position of the focusing lens system 52 with respect to the glass substrate 11 is determined based on the installation position of the origin limit switch 58 in the Z-axis direction.

The pulse laser oscillator 51 is electrically connected to the laser driver 61, the Z-axis actuator 57 is connected to the Z-axis actuator driver 62, and the origin limit switch 58 is connected to the origin limit detection device 63. The laser driver 61, the Z-axis actuator driver 62, and the origin limit detection device 63 are driven in accordance with electrical control signals from the control unit 64, respectively.

Next, the configuration and operation of scribing after forming an initial crack and an internal crack with a laser beam will be described with reference to FIG. FIG. 3 shows a state in which the glass substrate 11 shown in FIG. 1 is being cleaved to the center position. That is, FIG. 3 shows a state in which scribing is in progress after the formation of the laser initial crack has already been completed. In the following description, the process will be described from the first stage of forming the laser initial crack retroactively. .

In order to cleave the tempered glass, first, a laser initial crack is formed at the position of the starting end of the cleaving process of the cleaving line 12 of the glass substrate 11 by the initial crack forming apparatus 50 (see FIG. 1). The laser initial crack is divided into two parts, an internal crack 16 and a surface crack 17, in FIG.

First, an internal crack 16 is formed from the starting end of the planned cutting line 12 of the glass substrate 11. For this purpose, the glass substrate 11 placed on the movable table 32 (see FIG. 1) is moved in the + Y direction by the servo motor 33 (see FIG. 1) while the beam is stopped. And even if it outputs the laser beam 53, it retracts | saves to the position where the glass substrate 11 under it is not irradiated.


The height position adjustment by the Z-axis actuator 57 is set so that the height of the focal position 65 created by the laser beam 53 converged by the focusing lens system 52 is lower than the height of the upper surface of the glass. In response to the output command of the laser beam 53, the controller 64 moves in the −Y direction when the position of the Z-axis actuator 57 is at a predetermined position or when the Y-axis drive servomotor 33 (see FIG. 1) is driven. An output command is started after detecting conditions such as starting. Next, the step of forming the initial beam crack will be described with reference to FIG.

As shown in FIG. 4, the emission of the laser beam 53 is started in a state where the height of the focal position 65 is lower than the height of the upper surface of the glass. The movable table 32 (see FIG. 1) on which the glass substrate 11 is placed is moved in the −Y direction by the servo motor 33 (see FIG. 1), and at the same time, the laser beam 53 is irradiated to cleave the glass substrate 11. Move along the direction of the line. Then, the focal position 65 moves in the horizontal direction and touches the point P of the glass cross section. After that, by moving the focal point position 65 in the horizontal direction, the cloud point is formed in the glass substrate 11 in the form of a dot line or a continuous line of dots starting from the point P. The point cloud-like or linear cloudiness point forms the internal crack 16.

When the internal crack 16 reaches a predetermined length, if the focusing lens system 52 is gradually moved upward by the Z-axis actuator 57 while moving the movable table 32 while irradiating the laser beam 53, the internal crack 16 The tip extends toward the upper surface of the glass substrate 11 and eventually reaches the upper surface of the glass substrate 11. Thus, the internal crack 16 extending along the direction of the planned cutting line 12 from the end of the glass substrate 11 in the thickness direction of the glass substrate forms a surface crack 17 on the upper surface of the glass substrate 11. The position where the surface crack 17 is formed is provided at an inner position away from the starting end of the glass substrate 11 by a predetermined distance d. After the surface crack 17 is formed, the focal position 65 leaves the upper surface of the glass substrate 11 and moves to a higher position. When the Z-axis actuator 57 reaches a predetermined upper limit position and the focal position 65 is not located inside the glass substrate 11, the irradiation of the laser beam 53 is stopped. Through the above steps, the formation of the laser initial crack composed of the internal crack 16 and the surface crack 17 is completed.

Here, the reason that the internal crack 16 and the surface crack 17 are described separately for convenience is as follows. In the tempered glass, particularly in the chemically tempered glass, the region strengthened by the ion exchange method is only the surface tempered layer having a thickness of about several tens of microns, and the portion exceeding the depth is not tempered. When such a glass is subjected to surface scribing, it is preferable that the crack is penetrating at least the depth of the reinforcing layer on the glass surface as a preferable initial crack that can be a trigger. That is, as the required initial crack, the surface crack 17 penetrating the thin reinforcing layer is required, and the internal crack 16 inside the glass is not necessarily required. Thus, the meanings of the internal crack 16 and the surface crack 17 are shown separately depending on whether they are necessary for performing laser scribing.

Next, returning to FIG. 3, the operation after the initial laser crack formation will be described. The internal crack 16 and the surface crack 17 were formed by the laser beam 52 collected by the focusing lens system 52. Thereafter, the movable table 32 is moved in the + Y direction by the servo motor 33 and moved at a constant speed along the direction of the planned cutting line 12, and simultaneously, the irradiation of the CO2 laser beam is started. Then, an elongated laser heating unit 14 is formed on the glass substrate 11 by the CO2 laser beam by the cylindrical lens.

On the other hand, a cooling device 30 is disposed behind the beam shaping means 80, and a mixed medium of water and air is jetted downward from the cooling device 30. As a result, a cooling point 15 is formed at a position directly below the cooling device 30 on the glass substrate 11. Since the glass substrate 11 is moving along the direction of the planned cutting line 12 at a constant speed, the cooling point 15 is a laser beam along the direction of the planned cutting line 12 at a position spaced a predetermined distance from the rear end of the laser heating unit 14. The heating unit 14 is cooled.

As a result, a crack line 13 expanding from the surface crack 17 immediately below the cooling device 30 is generated in the thickness direction of the glass substrate 11. The crack line 13 expanded in the thickness direction in the vicinity of the surface crack 17 is in front of the planned cutting line 12 as the combination of the laser heating unit 14 and the cooling point 15 moves relative to the glass substrate 11. The crack can be expanded in the direction. As a result, the scribe groove 13 is formed along the planned cutting line 12 over the entire thickness of the glass substrate 11.

The scribe groove 13 thus formed is formed with the surface crack 17 as a starting point, and the position of the surface crack 17 is at an inner position away from the end of the glass substrate 11 by a predetermined distance d. Thus, by providing the position of the surface crack 17 on the inner side of the glass, the processing stability in forming the scribe groove 13 is increased. When the surface crack 17 is formed at the end of the glass using a diamond wheel as in the prior art, the glass is self-destructed by heating from the initial crack formed at the end, particularly in the case of tempered glass. In some cases, the formation of grooves was inhibited. However, in this embodiment, since the surface crack 17 is formed at a position apart from the end portion where the glass is easily broken, there is an advantage that the processing success rate of the scribe groove 13 is increased.

A surface crack 17 is formed on the glass surface, and an internal crack 16 is formed inside the glass. The internal crack 16 is effective when a break is applied to the glass substrate 11 by applying an external force. That is, when the glass substrate 11 is broken, no scribe groove is formed on the glass surface at a location between the end of the glass substrate and the surface crack 17 that is a distance d away. Therefore, if the internal crack 16 does not exist, the break surface will deviate from the planned cutting line and bend. In the glass processed in the present embodiment, the internal crack 16 has a portion that is easily broken inside the glass, so that the fractured surface at the time of the break can be guided along the internal crack 16. Can be prevented from falling off the planned cutting line. Therefore, even when the position of the surface crack 17 serving as the starting end of the scribe groove 13 is formed at an inner position separated from the end of the glass substrate 11 along the planned cutting line 12 by a predetermined distance d, the entire break surface is formed. Linearity is maintained.

Since the scribe groove 13 expanded from the surface crack 17 directly below the cooling point 15 proceeds in the depth direction of the glass substrate 11, there is no imbalance in the tensile stress acting in the creeping direction of the glass substrate 11, and the scribe groove 13 13 does not curve with respect to the planned cutting line 12.

On the other hand, when the combination of the laser heating part 14 and the cooling point 15 moves relative to the glass substrate 11 and reaches the terminal part on the planned cutting line 12 on the side opposite to the surface crack 17, the scribe groove When 13 reaches the end portion, the glass self-destructs from the end portion side, and a full cut crack surface from the surface of the glass to the bottom surface may occur. This is particularly noticeable in the case of tempered glass. Since the destruction of such a terminal portion is an uncontrolled cracking method, the end portion is often curved, which impairs the linearity of the break surface.

Therefore, as shown in FIG. 5, the internal crack 16 and the surface crack 17 are also formed at the position along the planned cutting line 12 at the terminal portion opposite to the internal crack 16 and the surface crack 17 of the glass substrate 11. The internal crack 19 and the surface crack 20 are formed in the same procedure. Further, when forming the scribe groove by the CO2 laser beam, the laser heating unit 14 (see FIG. 3) stops the irradiation of the CO2 laser beam at the timing just approaching the position of the surface crack 20. As a means for stopping the irradiation of the CO2 laser beam at an accurate timing, a mechanical external shutter mechanism for the CO2 laser beam may be used, or a mechanism for selecting the polarization direction by the Faraday rotator may be simply used. It may be a means for turning off the beam output command of the CO2 laser. Since the heating region is not formed between the surface crack 20 and the glass end portion by the irradiation timing control means of the CO2 laser beam, no scribe groove is formed in the glass end portion. In this way, in the terminal portion of the glass substrate 11, no cracks due to self-destruction are formed, and when the glass substrate 11 is broken, the internal crack 19 guides the surface of the break, It is possible to prevent the break surface from falling off the planned cutting line.

  FIG. 6 is a conceptual diagram for explaining the operating principle for carrying out the method for cleaving tempered glass in Example 2. In Example 1, as shown in FIG. 4, the surface crack 17 was formed by first moving the focal point of the laser beam horizontally inside the glass substrate 11 and then lifting it obliquely upward to form an internal crack. However, in the present embodiment, the internal crack 16 as the initial crack is formed in a straight line that passes obliquely upward in the glass substrate 11, and the surface is located at a position where the linear internal crack 16 protrudes from the surface of the glass substrate 11. A crack 17 is formed.

FIG. 8 shows a photograph of a cross section of chemically strengthened glass sample-processed by the configuration and method shown in Example 2. The glass thickness is 1.1 mm, the processing conditions for forming the laser initial crack are laser average power 1.0 W, pulse width 10 nsec, repetition frequency 6 kHz, glass horizontal feed rate 1 mm / sec, and Z axis actuator. The ascending feed speed in the vertical direction is 0.3 mm / sec. In this sample, when the focal position reaches the surface, the ascending speed of the Z-axis actuator is reduced to 0.1 mm / sec, so that the surface crack is long.

Returning to FIG. 6, in order to form the internal crack 16 in a straight line passing diagonally upward in the glass substrate 11, the movable table 32 is moved in the −Y direction in FIG. 1 in the configuration of FIG. 3 or 4. Once moved, the laser beam 53 is irradiated and retracted to a position where there is no glass substrate 11 below, and the Z-axis actuator 57 is operated by the Z-axis actuator driver 62 to move the focusing lens system 52 downward. The optical path of the laser beam from the laser oscillator 51 is adjusted by the reflecting mirrors 54 and 55 and shaped by the beam expander 56, and then the focal point of the laser beam 53 incident on the focusing lens system 52 is as shown in FIG. The glass substrate 11 is irradiated with the laser beam 53 so as to be positioned in the interior P at the end of the glass substrate 11.

Next, the movable table 32 on which the glass substrate 11 is placed with the laser beam 53 irradiating the glass substrate 11 is moved by the servo motor 33 in the + Y direction and along the direction of the planned cutting line 12. When the focusing lens system 52 is gradually moved upward at a constant speed by the Z-axis actuator 57, the tip of the internal crack 16 linearly extends obliquely upward in the glass substrate 11, and the glass substrate 11 The process reaches the upper surface to form a scratch as a surface crack 17 and finish. The order in which the cracks are made may be the order in which the surface cracks 17 are formed first and the internal cracks 16 are formed later. Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

FIG. 7 is a conceptual diagram illustrating the operating principle for carrying out the tempered glass cleaving method in Example 3. In this embodiment, the internal crack 16 as an initial crack is formed in a waveform such as a sine wave or a sawtooth wave in the glass substrate 11, and the focal position of the laser beam 53 is not brought out on the surface while the glass substrate 11 is moving horizontally. In addition, the internal crack 16 is maintained so as to swing up and down inside the glass substrate 11. When the internal crack 16 of this waveform becomes a predetermined length, the focusing lens system 52 is moved by the Z-axis actuator 57 while moving the movable table 32 along the direction of the planned cutting line 12 while irradiating the laser beam 53. When it is gradually moved upward, the corrugated internal crack 16 gradually bends upward in the glass substrate 11 and extends toward the upper surface of the glass substrate 11. Then, when the focal point of the laser beam 53 is moved while swinging up and down inside the glass substrate 11, and the focal point of the laser beam 53 intersects the surface of the glass substrate 11 one or more times, the corrugated internal crack 16 becomes glass. The surface of the substrate 11 is crossed one or more times and connected to the scratch as the surface crack 17.

FIGS. 9 and 10 show photographs of a cross section of chemically strengthened glass having a thickness of 1.1 mmt processed by the configuration and method shown in Example 3. FIG. In particular, as shown in FIG. 10, the reinforcing layer can be penetrated a plurality of times by vibrating the focus position up and down in the vicinity of the surface position of the glass.

Also in this embodiment, when the corrugated internal crack 16 intersects the surface of the glass substrate 11 without forming the surface crack in advance, the surface crack 17 is formed by continuing the irradiation of the laser beam 53 at that position. May be. In this case, when the corrugated internal crack 16 intersects the surface of the glass substrate 11 once, the surface crack 17 is one place. However, the surface crack 17 may be intersected a plurality of times. Cracks are formed in a continuous state.
Other configurations and operations are the same as those of the first embodiment or the second embodiment, and thus description thereof is omitted.

The method and apparatus for cleaving tempered glass according to the present invention include a tempered layer formed on a glass surface used for display devices such as flat panel displays such as liquid crystal displays and plasma displays, mobile phones and portable terminals in recent years. It is suitable for application to mirror cutting of glass or thick glass.

11 glass substrate 13 scribe groove 14 laser heating portion 15 cooled points 16 and 19 inside the crack 17, 20 surface cracks 25 CO ₂ laser 26 laser beam 27 beam expander 28 reflector 30 cooling device 32 movable table 33 servo motor 50 first crack Forming device 51 Pulse laser oscillator 52 Focusing lens system 53 Laser beam 54, 55 Reflector 56 Beam expander 57 Z-axis actuator 58 Origin limit switch 61 Laser driver 62 Z-axis actuator driver 63 Origin limit detection device 64 Control unit 65 Focus position 80 Beam shaping means

Claims (9)

A glass substrate is scribed on the glass substrate by heating with the first laser beam along the planned cutting line of the glass substrate, and relatively moving the heating position of the glass substrate with the first laser beam along the planned cutting line. A method of cleaving the glass substrate to form a second laser beam having a wavelength in the visible region to the ultraviolet region, the focal point of which is a surface at an inner position along the planned cutting line from the edge of the glass substrate To form a surface crack that is the initial crack that is the starting point of scribing, and the second laser beam is focused by setting the focal point of the second laser beam inside the glass substrate. It is moved relative to the glass substrate to form an internal crack extending from the surface crack through the inside of the glass substrate and extending to an end surface of the glass substrate. Fracturing method of the glass substrate. 2. The method for cleaving a glass substrate according to claim 1, wherein the scribing is caused to start from a scratch that becomes the initial crack by spraying a cooling medium onto the region heated by the first laser beam to cool the region. 2. The method for cleaving a glass substrate according to claim 1, wherein the second laser beam is a laser beam in a wavelength region showing green in the visible region. 2. The method for cleaving a glass substrate according to claim 1, wherein the glass substrate is a tempered glass having a tempered layer formed on a surface thereof or a thick glass having a thickness of 3 mm or more. The internal crack is formed by a straight line portion extending from the end face of the glass substrate toward the inside of the glass substrate and a curved portion extending from the inside of the glass substrate toward the surface crack on the surface of the glass substrate. The method for cleaving a glass substrate as described in 1. 2. The method for cleaving a glass substrate according to claim 1, wherein the internal crack is formed by a straight portion extending from the end face of the glass substrate to the inside of the glass substrate and reaching the surface of the glass substrate. The internal crack is formed by the first corrugated portion extending from the end face of the glass substrate toward the inside of the glass substrate and the second corrugated portion extending from the inside of the glass substrate toward the surface crack on the surface of the glass substrate. The glass substrate cleaving method according to claim 1, wherein the glass substrate is cleaved. A glass substrate is scribed on the glass substrate by heating with the first laser beam along the planned cutting line of the glass substrate, and relatively moving the heating position of the glass substrate with the first laser beam along the planned cutting line. A glass substrate cleaving apparatus for forming a glass substrate, a movable table on which the glass substrate is mounted and movable at least in the direction of the cleaving line, and a first laser beam irradiation for forming a heating region on the cleaving line Means, a second laser beam irradiating means having a wavelength from the visible region to the ultraviolet region for forming an initial crack in the glass substrate, and cooling for locally cooling by injecting a refrigerant at a position on the planned cutting line And a focal position adjusting means for moving the laser beam from the second laser beam irradiation means in a direction perpendicular to the surface of the glass substrate. Breaking apparatus of the glass substrate. A tempered glass comprising a surface crack which is an initial crack which is a starting point of scribing on the surface of the glass substrate, and an internal crack which extends from the surface crack to the end surface of the glass substrate through the inside of the glass substrate.