JPH09150286A - Method and apparatus for cutting brittle material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the cutting speed in a glass cutting system to divide a large glass sheet into small pieces. SOLUTION: The laser beam having the thin and long beam spot shape of at least 20mm, more preferably at least 30mm, and further maximum 40mm is transferred across the glass sheet to generate a local crack notch line. The glass sheet is then divided along the notch line by adding the bending moment in the local crack region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting glass sheets and other fragile materials, and more particularly to a laser cutting process speed effective when used in the process of making glass substrates for flat panel displays. It is about how to increase.

[0002]

2. Description of the Related Art Conventionally, a laser has been used to divide a glass plate. PCT Patent No. WO 93/20015 to Kondratenko describes the use of laser light in spreading so-called blind cracks across a glass sheet in order to divide the glass sheet in two. This partial crack extends to the middle of the depth of the glass sheet and substantially acts as a cutting line. The sheet is then mechanically bisected along the score line.

In one specific form, small cuts or cuts are made on one side of the glass sheet, and then laser light is used to form partial cracks and the cuts or cuts are spread through the glass sheet. Then, the laser light is brought into contact with the glass sheet in the region of the cut or notch, the laser and the glass sheet are relatively moved, and the laser light is propagated in the desired path of the cut line. It is desirable to direct a stream of fluid coolant to the heated surface portion of the glass downstream of the laser so that the laser light heats an area of the glass sheet and then the heated area is rapidly cooled. Thus, the heating of the glass sheet by the laser and the cooling of the glass sheet by the aqueous coolant distort the glass sheet and spread the cracks in the direction in which the laser light and the coolant pass.

According to Kondratenko, the shape of the beam on the glass sheet is elliptical, and the minor axis and major axis of the elliptical shape satisfy the following relationship.

A = 0.2 to 2.0h b = 1.0 to 10.0h where a and b are the minor and major axes of the elliptical spot, and h is the thickness of the material cut by the laser beam. Is. According to Kondratenko, b is 10.0h
If it is larger than the above, the accuracy of cutting is reduced.
Therefore, for a glass substrate with a thickness of 0.7 mm, Kondr
According to Atenko, the long axis of the beam spot is 7mm
It can't be more.

[0006]

Due to the development of such cutting technique by laser light, the quality of the cut surface is somewhat good, and the quality of the cut surface is desired to be very high. They are an effective means for manufacturing panel substrates for liquid crystal and other flat panel displays. However, despite considerable efforts made over the last few years to develop that process, flat panel displays (L
Cutting rates that are practically sufficient for use in manufacturing substrates such as CDs have not been achieved. In fact,
The maximum cutting speed reported in the Kondratenko patent example is 120 mm / sec, and in most other cases is much less than this mediocre cutting speed.

[0007] Recently, at the trade exhibition held in Munich, Germany, July 19-23, 1995, Jenopt
The document published by ik states that it was possible to make laser cuts at a speed of 30-150 mm / sec. Jenotipik is Kondratenk
It uses the same laser scoring process described in the O. patent.

In the manufacture of flat panel display substrates, high cutting speeds that make these processes practical, eg at least about 300 mm / sec, even at least 500 mm / sec, even 100.
It is desirable to implement a laser cutting process that allows a speed of 0 mm / sec.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a method of cutting a glass sheet (or other brittle material) that traverses the glass sheet to induce cracks along the path of a laser beam. Move the extremely elongated laser beam (and any coolant) in the desired path. Due to the thermal gradient generated by this, tensile stress is generated in the surface layer of the glass, and when this stress exceeds the tensile strength of the glass, the glass descends into the area where the blind crack and the scoring line are in the compressed state and becomes the material. It will come in. Then when the laser light crosses the glass,
The crack follows the laser light. The depth of the crack,
The shape and direction are determined by the stress distribution, and the power density, size, and shape of the beam spot, the relative velocity of the beam spot and the material, the properties and characteristics of the coolant supplied to the heating area, and the material of the cracked material. It depends on several factors, including thermophysical and mechanical properties and its thickness. By using a laser beam with an extremely elongated beam spot on the glass and locating this elongated beam spot in the direction of propagation of the desired split line on the glass sheet,
It has been found that higher laser cutting rates can be achieved than using methods according to known techniques.

As described above, in the present invention, the laser spot has an extremely elongated shape, for example, an elliptical shape. The long axis of this elongated shape is preferably 20 mm or more, more preferably 30 mm or more, and further preferably 40 mm or more.

It may be desirable for the minor axis of the beam to be narrow enough to not compromise the quality of the cut surface when forming a straight cut surface.

In the present invention, it is desirable that the laser light has a non-Gaussian intensity distribution. In one embodiment, the intensity of the laser beam is preferably bi-peak mode, that is, such as a laser that operates in one or more levels, eg, including both TEM _{01 *} and TEM ₀₀ modes. It is desirable to direct a suitable coolant flow to the region of material along the direction of travel of the beam spot in order to cause a very localized cooling of the surface layer along the cutting line.

[0013]

According to the present invention, from about 0.4 mm to 3.
With a glass thickness of 0 mm, a cutting speed of 300-700 mm / sec or more can be achieved without impairing the cutting accuracy or the cut surface of the glass.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for cutting glass sheets along desired cutting lines using laser cutting techniques. As shown in FIG. 1, in the glass cutting system of the present invention, a glass sheet 10 has an upper surface 11 and a lower main surface 11. Since the glass sheet 10 first forms the crack starting point 19 at one end of the glass sheet 10, a cut line or a cut line is made along one end of the glass sheet. This crack initiation point 19 is then used to move the laser beam 16 across the glass sheet in the path of the desired cutting line to form the crack 20. The laser light effectively heats the glass sheet in localized areas along the desired cutting line. The resulting temperature gradient causes a tensile stress in the surface layer of the material, and when the stress exceeds the tensile strength of the material, blind cracks in the material descend into the region of compression and enter the material. A water jet 22 adds water coolant to enhance the stress distribution and thereby promote crack propagation. As the laser beam traverses the glass, cracks follow the path traveled by the laser beam.

Since the surface temperature of the glass 10 is directly dependent on the time of exposure to the laser beam, the use of an elliptical beam instead of a circular cross section will allow the glass surface to move along the cutting line at the same relative velocity. The heating time at each point can be extended. Thus, at the specified power density of the laser beam 16, the distance from the laser beam spot to the front edge of the cooling spot, which is important for maintaining the depth required to heat the glass 10, is the same. However, the laser beam spot spreads more in the moving direction,
And also will make the relative velocity of the laser beam spot and material more acceptable.

As shown in FIG. 2, in the present invention, the laser spot is extremely elongated, for example, elliptical, and has a diameter of 20 mm or more, more preferably 30 mm or more.
Furthermore, it is desirable to have a long axis of 40-100 mm or more. The long axis of the laser beam spot is in the direction of propagation of the desired cutting line across the glass sheet. For thin sheets of glass (1.1 mm or thinner), the optimum length of the long axis of the laser beam spot is related to the desired propagation velocity, with the long axis b being greater than 10% of the desired laser cutting speed per second. Larger is desirable. in this way,
Laser cutting rate of 5 with 0.7mm thick glass
At 00 mm, the long axis of the laser is preferably at least 50 mm long.

It is desirable that the cracks 20 spread only in the depth direction of the glass sheet 10 (distance d), so that the cracks 20 act as cutting lines. The final division of the glass sheet into smaller sheets is done by applying a bending moment to the cracks 20. The bending can be accomplished by conventional bending equipment (not shown) and techniques such as those used to cut glass in the process of using conventional mechanical surface cutting methods.
Since crack 20 uses a laser cutting technique rather than a mechanical incision, the formation of glass chips during the mechanical cutting process can be minimized as compared to conventional techniques.

The laser beam used in the glass cutting process must heat the glass surface to be cut. Consequently, it is desirable that the emitted light of the laser be of a wavelength that the glass absorbs. For this to occur, the emitted light is 2
Infrared rays having a wavelength of not less than μm are desirable, for example, a CO ₂ laser having a wavelength of 9-11 μm and a C having a wavelength of 5-6 μm.
A beam such as an O laser, an HF laser having a wavelength of 2.6 to 3.0 μm, or an erbium YAG laser having a wavelength of about 2.9 μm is preferable. Most of the experiments used a CO ₂ laser with a power of 150-300 watts, but it seems more successful with a higher power laser.

Cracks 20 form in the glass towards the interface of the heating and cooling zones, which is the zone of maximum thermal gradient. The crack depth, shape, and direction are determined by the distribution of thermoelastic stress, and are mainly based on the following multiple factors.

The power density, size and shape of the beam spot; the relative velocity of the beam spot and the material; the thermophysical properties, the quality, the conditions for supplying the coolant to the heated area; In order to optimize the cutting cycle for materials with different mechanical properties, their thicknesses and surface conditions, it is necessary to establish an appropriate relationship between the main parameters and the variables of the cutting process. International Patent No. WO93 / 2
2, the speed of relative displacement of the beam spot 18 across the glass 10 is dependent on the dimensions of the beam spot 18 and the distance l from the region where the cooling water flows, as described in US Pat. V and the depth d of the crack 20 are represented by the following equation.

V = ka (b + 1) / d where V is the relative velocity between the beam spot and the material, and k
Is a proportional coefficient depending on the thermophysical properties of the material and the power density of the beam, a is the width of the beam spot, b is the length of the beam spot, l is the distance from the near end of the beam spot to the front end of the cooling zone, d is the depth of the blind crack 4.

The laser operates by lasing which occurs in a resonator defined by a mirror at each end. The concept of a stable resonator can be most clarified by tracing the optical path of a ray through the resonator. The stability threshold is reached when a ray parallel to the axis of the laser cavity is permanently reflected back and forth between two mirrors without loss.

Resonators that do not reach the stability criterion are called unstable resonators because the light rays deviate from the axis. There are many types of unstable resonators. One simple example is a convex spherical mirror as opposed to a plane mirror. Others include concave mirrors of different diameters (light reflected from a large mirror escapes around the edges of a small mirror) and a pair of convex mirrors.

The two types of resonators have different advantages and different mode patterns. A stable resonator concentrates light along the laser axis and efficiently extracts energy from that region, but not from the peripheral region away from the axis. The resulting beam has an intensity peak in the center and the intensity diminishes Gaussian away from the axis. This is the standard type used with low gain continuous wave lasers.

Unstable cavities tend to spread the light inside the laser cavity over a larger volume. For example, the output beam may have an annular shape with a ring-shaped intensity peak around the axis.

There are two types of different modes in the laser cavity: the transverse mode and the longitudinal mode. Transverse modes exist in the cross-sectional shape or intensity pattern of the beam. Longitudinal modes correspond to different resonant modes due to the laser cavity length occurring at different frequencies or wavelengths within the gain band of the laser. Single transverse mode lasers that oscillate in a single longitudinal mode oscillate at a single frequency, while those that oscillate in two longitudinal modes are at two independent wavelengths (usually in close proximity).
It oscillates at the same time.

The electromagnetic field "shape" within the laser cavity depends on the curvature of the mirror, the spacing, and the cavity diameter of the discharge vessel. Even if the arrangement and spacing of the mirrors and the wavelength are slightly changed, the "shape" (electromagnetic field) of the laser beam is greatly changed.
A special term has been developed in describing its "shape" and the spatial energy distribution of the beam, where transverse modes are classified according to the number of local minima appearing in the bidirectional beam cross section. The lowest order mode, the fundamental mode, has an intensity peak in the center and is known as the TEM ₀₀ mode. This is a conventionally used laser having a Gaussian intensity distribution as shown in FIG. The modes with one local minimum along one axis and no local minimum along its vertical axis are TEM _{01 *} or TEM ₁₀ , which are determined by their orientation. An example of the intensity distribution for the TEM _{01 *} mode is shown in FIG. 3 (distance across the beam d
Beam intensity for I). For most laser applications, the TEM ₀₀ mode is considered the most desirable. However, non-Gaussian modes such as TE
It has been found that M _{01 *} mode and TEM ₁₀ mode beams can be used to more uniformly deliver laser energy to the glass surface. As a result, it was found that higher laser cutting speeds can be achieved with lower power than if the laser has a Gaussian intensity distribution. Further, the laser power can be used in a wider range due to the expanded operation range of the laser cutting process. This is probably because the non-Gaussian laser beam can further improve the uniformity of energy distribution over the entire beam.

The laser beam shown in FIG. 3 has a ring shape. As described above, the power distribution shown in FIG. 3 is a cross section of the power distribution of the ring-shaped laser beam. A non-Gaussian beam in which at least one pair of intensity peaks are located at the outer periphery of the central region having a lower power distribution is desirable in the present invention. Thus, it is desirable that the center of the laser beam has a power intensity lower than the power intensity of at least a plurality of outer peripheral regions of the laser beam. This low power center region may be completely zero power level, in which case the laser beam will have a T% of 100%.
EM _{01 *} Power distribution. However, the laser beam has a two-peak mode, ie, as shown in FIG.
It may be a combination of one or more mode levels such as a combination of TEM _{01 *} mode and TEM ₀₀ mode in which the power distribution in the central region is simply lower than the power distribution in the outer peripheral region. When the beam is in the two-peak mode, it is desirable that the beam has a combination of 50% or more in the TEM _{01 *} mode, more preferably 70% or more in the TEM _{01 *} mode, and the rest in the TEM ₀₀ mode.

As a preferred specific embodiment of the present invention, a system controller (not shown) such as a digital computer is provided in a system for controlling the movement of a laser, a glass sheet, and other movable parts on the system. Connecting. The system controller uses conventional machine control techniques to control the movement of various parts of the system. The system controller uses various manufacturing operating programs stored in its memory, each of which is suitable for moving a laser or glass sheet (and other moving parts if necessary) for a particular size glass sheet. It is desirable to be designed to control the

The following example demonstrates the method according to the invention.

Example 1 This example illustrates the operation of a CO ₂ laser with a Gaussian power distribution.

Laser 16 was a Model 1200 axial-flow two-beam CO ₂ laser manufactured by PRC Corporation. The beam operated in TEM ₀₀ mode and was placed about 2 meters from the glass surface with a spot size of about 12 mm (laser beam diameter at the laser emission point).
A pair of cylindrical lenses was placed in the optical path of the laser between the laser and the glass surface to deform the laser spot. As a result, the laser spot for applying the laser to the glass has a length of about 45 to 50 mm and a width of about 0.
An elongated elliptical beam having a diameter of 1 to 0.15 cm was used. The fundamental mode of the cavity of this laser is TEM ₀₀ . When this is the only mode in which the resonator can oscillate, the resonating 00-mode laser will propagate with as little divergence as possible and be focused with the smallest spot size. In this example, the laser power distribution was Gaussian (operating in TEM ₀₀ mode) by utilizing a "planar" optical coupler at the laser front facet with a small internal aperture.

About 500 mm width x 500 mm length x about 1.1
A mm-thick aluminosilicate glass sheet 10 was manually scored at the edge of the glass sheet to form a crack initiation point 19. Thereby, a small incision line having a length of about 8 mm and a depth of about 0.1 mm was formed at one end of the upper surface of the glass to form a crack starting point 19. The glass sheet 10 is positioned so that the laser 16 contacts the crack initiation point 19 and causes the glass sheet 10 to travel in a straight path across the glass sheet at the power and speed listed in Table 1 below. I moved it along.

Table 1 Laser velocity Peak power (W) Success probability (%) 400 mm / sec 120 100 420 mm / sec 120-165 100 465 mm / sec 165-175 100 475 mm / sec 165-179 100 480 mm / sec 168-179 66 The 500 mm / sec 183-188 33 success probability column represents the best performance achieved in the corresponding power range. The 100% success rate indicates that in the power range described, the laser had operating parameters that were substantially 100% successful over the glass sheet over time.

Example 2 The same method, apparatus and laser as described in Example 1 were used, with the resonator operating the laser with a higher mode power distribution. In particular, the laser is in two peak mode,
It is composed of a plurality of sub-beams, each of which has an intensity distribution. Since these beams are independent, their net distribution is the algebraic sum of the individual shapes, weighted by the power rate of each mode. By way of example, the amount of TEM ₀₀ mode can be reduced by changing the curvature of the optical coupler or increasing the diameter of the opening. In this example, the power distribution of the laser was changed to a mixing ratio of TEM _{01 *} mode and TEM ₀₀ mode of about 60:40 (a spot size of about 14 mm) and a beam length of about 50-60 mm. This is 2
It was achieved by replacing the concave optical coupler with a radius of curvature of 0 meters with a "planar" optical coupler, resulting in a larger aperture. The laser power and speed varied as described in Table 2.

Table 2 Laser velocity Peak power (W) Success probability (%) 300 mm / sec 90-145W 100 500 mm / sec 155-195W 100 600 mm / sec 200W 100 650 mm / sec 200-220W 100 700 mm / sec 250W 50 Example 1 Higher cutting speeds were achieved with lower laser power when the laser used in the above was converted to a non-Gaussian laser with TEM _{01 *} mode. In addition, a wider range of laser power was allowed to make a satisfactory cut edge. As can be seen by comparing the results of Example 1 and Example 2, the Gaussian laser was able to achieve 100% cutting (successfully carved almost all samples) at a cutting speed of up to 475 mm / sec. Above these speeds,
It has been difficult to obtain consistently satisfactory results. However, it is expected that velocities of 1000 or 2000 mm / sec will be achieved using the beam lengthening method of the present invention.

Example 3 In this example, the laser producing the laser beam is an axial flow CO ₂
Model SS / 200 / of a 600W / tube two-beam laser manufactured by PRC Corporation.
2. The beam had a spot size of about 12 mm in TEM ₀₀ mode. The laser was placed approximately 2 meters from the glass surface. A pair of cylindrical lenses was placed in the path of the laser beam between the laser and the glass surface to deform the laser spot. As a result, the laser spot became an elongated elliptical shape having a length of about 40 to 50 mm when hitting the glass and a width of about 1 to 1.5 mm at the midpoint. The laser power distribution was a 60:40 mix of TEM _{01 *} and TEM ₀₀ modes, which was achieved by using a 20 meter radius of curvature concave optical coupler at the laser front facet. Laser power is 160-20
The laser speed across the glass sheet, varying between 0 W, was about 500 mm / sec.

The glass sheet 10 has a width of about 500 mm × 50.
Alumina silicate glass sheet of 0 mm length × about 1.1 mm thickness, three times on one side of the sheet in the first direction, and on the other side of the sheet in the second direction orthogonal to the direction of the first laser cut line. Was laser-cut 3 times 9 times. This type of scoring method can double the manufacturing work efficiency in the production of LCD substrate glass, where the outermost scoring line removes the outer edge of the glass sheet and the middle scoring line on each side of the sheet 4 remaining glass
It separates in cooperation with one used member. By using three score lines on each side of the glass sheet, the path of the score lines on one side of the sheet resulted in nine intersections intersecting the score lines on the other side of the sheet.

To achieve this, the glass sheet 10
Manually scored each side along the edge of the glass sheet to form three crack initiation points 19 where the laser score lines were desired. This allows
Approximately 1-8 mm long and approximately 0.1 mm at one end of the glass top
Three crack initiation points 19 were formed in the form of scoring lines of small depth. The crack does not have to be 4-8 mm, but rather a crack that allows the laser to spread is sufficient to act as a crack starting point. On the glass sheet 10, the laser 16 causes a crack starting point 1
The glass sheet 10 is positioned so that it contacts one of the glass sheets 9 and the path of the laser 16 follows a straight path that traverses the glass sheet forming the score line 20, as shown in FIG.
Moved. This process was repeated to form each of the three score lines 20 on the first side of the glass sheet.

Then, the glass sheet 10 was turned upside down to expose the opposite side of the glass sheet 10. Sheet 10
Is manually scored along the edge of the glass sheet to form three other crack initiation points 10 and again the path of the laser 16 is a straight path across the glass sheet to form three score lines 20. The glass sheet 10 was moved along the line. The three score lines made on the second side of the sheet are orthogonal to the opposite side of the three score lines formed on the first side of the glass sheet 10 and at right angles to the path of each of the three score lines. Formed.

Then, a bending moment was applied to the cut lines 20 in order to separate the glass sheet 10 along the cut lines 20. The resulting sheets were then turned over and a bending moment was applied to the sheets in the region of their respective score lines 20, thereby dividing them into smaller sheets. This process was repeated for 100 or more glass sheets, thereby forming 900 or more intersections where the paths of the cut lines 20 intersect the paths of the cut lines 20 located on the opposite side of the glass sheet. In all cases, the split ends were consistently of very high quality.

Example 4 In this example, a single CO ₂ was used to remove portions of the protective plastic layer and divide the glass sheet 10 into smaller sheets.
Laser 16 was used. The glass sheet is about 400 mm wide x 400 mm long x 1.1 mm thick, and is a Main Tape.
It was a LFC-3 mask film produced by Corporation coated with a protective layer. L
FC-3 is a polyethylene film material, about 0.002
Inch thick, stored in rolls, with acrylic adhesive on one side. The film was applied to the glass with the adhesive in contact with the glass sheet, and the coated glass was then squeezed between a pair of rollers to promote adhesion between the glass and the film.

In this example, laser 16 was a Model 1200 axial-flow two-beam CO ₂ laser manufactured by PRC Corporation. The laser beam has a diameter of about 7 mm at the exit end of the laser, so the spot size emitted from the laser is about 38.5 mm ² ,
Operating at 0 W, the beam power density is about 1.82 W / m
It became m ^2. The laser was placed approximately 2 meters from the protective layer on the glass surface. A pair of cylindrical lenses are arranged in the laser optical path between the laser and the glass surface to form the laser spot. As a result, the laser spot shape on the protective layer is approximately 33 mm long and 2 mm in the middle.
It has an elongated elliptical shape with a width of about 1.35 W / mm ^2.
Became the power density of. Place the glass sheet under the laser 16 at about 250 mm / min. Moved at the speed of. Laser 1
No. 6 vaporized all the protective layers in contact with the laser, thereby selectively removing the protective layers, and the removed stripes 14 had a width of about 2 mm. There was no residue in the area where the protective layer was removed, and the residue of the protective layer was completely removed.

At the edge of the glass sheet, a crack initiation point 19
The glass sheet 10 was manually scored to form the. Incisions were made in the glass in areas 14 where the protective layer was selectively removed. As a result, a crack starting point 19 was formed at one end of the upper surface of the glass in the form of a small cutting line having a length of about 8 mm and a depth of about 0.1 mm. The glass sheet 10 was placed so that the laser 16 was in contact with the crack initiation point 19 and the glass sheet 10 was moved so that the path of the laser 16 was along the same path as the first scan of the laser 16. As a result, the laser 16 propagated in the selective removal portion 14 of the protective layer. About 250 mm / min. The glass sheet 10 was moved at the speed of. The laser effectively heated the glass in the area where the laser was applied to the glass surface. Local heating by the laser causes the crack to propagate across the glass surface, starting at the crack initiation point 19,
The crack propagated along the path of the laser 16. The crack was about 0.1 mm deep. Manual pressure was applied to the glass sheet to apply a bending moment to the laser-generated crack, thereby splitting the glass sheet into two sheets.

[Brief description of the drawings]

FIG. 1 is a perspective view of a glass cutting method step according to the present invention.

FIG. 2 is an enlarged view of a laser beam spot on the glass surface in the process shown in FIG.

3 is a graph showing a desired intensity shape of the laser shown in FIGS. 1 and 2. FIG.

FIG. 4 is a graph showing a power distribution of a standard Gaussian laser.

[Explanation of symbols]

 10 glass sheet 11 glass sheet main surface 16 laser beam 18 laser spot 19 crack starting point 20 crack 22 water jet

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[Procedure amendment]

[Submission date] July 3, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

At the edge of the glass sheet, a crack initiation point 19
The glass sheet 10 was manually scored to form the. Incisions were made in the glass in areas 14 where the protective layer was selectively removed. As a result, a crack starting point 19 was formed at one end of the upper surface of the glass in the form of a small cutting line having a length of about 8 mm and a depth of about 0.1 mm. The glass sheet 10 was placed so that the laser 16 was in contact with the crack initiation point 19 and the glass sheet 10 was moved so that the path of the laser 16 was along the same path as the first scan of the laser 16. As a result, the laser 16 propagated in the selective removal portion 14 of the protective layer. About 250 mm / min. The glass sheet 10 was moved at the speed of. The laser effectively heated the glass in the area where the laser was applied to the glass surface. Local heating by the laser causes the crack to propagate across the glass surface, starting at the crack initiation point 19,
The crack propagated along the path of the laser 16. The crack was about 0.1 mm deep. Manual pressure was applied to the glass sheet to apply a bending moment to the laser-generated crack, thereby splitting the glass sheet into two sheets. Hereinafter, preferred embodiments of the present invention will be described. (Embodiment Mode 1) In a flat glass sheet manufacturing method including a step of moving a laser beam across a glass sheet to form a crack across the glass sheet, the laser beam has an elongated beam spot on the glass sheet. A method for manufacturing a flat glass sheet, wherein the beam spot has a longest dimension of 20 mm or more. (Embodiment 2) Embodiment 1 is characterized in that the moving step includes a step of moving a laser beam having a beam spot having a longest dimension of about 30 mm or more.
The described method. (Third Embodiment) The first embodiment is characterized in that the moving step includes a step of moving a laser beam having a beam spot having a longest dimension of about 40 mm or more.
The described method. (Embodiment 4) The method according to Embodiment 1, wherein the moving step comprises a step of moving the laser beam with respect to the glass sheet at a speed of at least 300 mm / sec. (Embodiment 5) The method according to Embodiment 1, wherein the moving step comprises a step of moving the laser beam with respect to the glass sheet at a speed of at least 400 mm / sec. (Embodiment 6) The method according to Embodiment 1, wherein the moving step comprises a step of moving the laser beam with respect to the glass sheet at a speed of at least 500 mm / sec. (Embodiment 7) The moving step is at least 300
Embodiment 1 comprising moving the laser beam having a beam spot whose longest axis is about 10% or more of the velocity at a velocity of mm / sec.
The described method. (Embodiment 8) The method according to Embodiment 1, wherein the laser beam in the moving step comprises a non-Gaussian component. (Embodiment 9) The method according to Embodiment 2, wherein the laser beam in the moving step comprises a non-Gaussian component. (Embodiment 10) The method according to Embodiment 9 wherein the laser beam in the moving step is a combination of TEM ₀₁ mode and TEM ₀₀ mode. (Embodiment 11) The laser beam in the moving step is composed of at least 50% of TEM ₀₁ mode components,
The method of embodiment 10 wherein the rest is in TEM ₀₀ mode. (Embodiment 12) A method for dividing a glass substrate having a thickness of 0.4 mm to 3.0 mm, which is used for a flat panel display, wherein the method produces a flat glass sheet having a thickness of about 0.4 mm to 3.0 mm. And a moving step of moving a laser beam on the glass sheet at a speed of at least 300 mm / sec, the laser beam having an elongated beam spot on the glass sheet, the beam spot having a length of 20 m.
A method for dividing a glass substrate, having a longest dimension of m or more, and sufficiently forming cracks traversing the glass sheet by the moving step. (Embodiment 13) The embodiment 12 is characterized in that the moving step comprises a step of moving a laser beam having a beam spot having a longest dimension of about 30 mm or more.
The described method. (Embodiment 14) The method according to Embodiment 12, wherein the moving step comprises a step of moving a laser beam having a beam spot having a longest dimension of about 40 mm or more. (Embodiment 15) The method according to Embodiment 12, wherein the moving step comprises a step of moving the laser beam with respect to the glass sheet at a speed of at least 400 mm / sec. (Embodiment 16) The method according to Embodiment 12, wherein the moving step comprises a step of moving the laser beam with respect to the glass sheet at a speed of at least 500 mm / sec. (Embodiment 17) The embodiment 12 is characterized in that the moving step comprises a step of moving the laser beam having a beam spot whose longest axis is about 10% or more of the velocity. Method. (Embodiment 18) The method according to Embodiment 12, wherein the laser beam in the moving step comprises a non-Gaussian component. (Nineteenth Embodiment) The method according to the thirteenth embodiment, wherein the laser beam in the moving step comprises a non-Gaussian component. (Embodiment 20) The method of embodiment 13 wherein the laser beam in the moving step is a combination of TEM ₀₁ mode and TEM ₀₀ mode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Roger Alfie Aleyl New York, USA 14814 Big Flats Owen Harrow Road 3886 (72) Inventor Harry Menegas United States New York 14812 Beaver Damms Hornby Road 1014 (72) Inventor Bruce Herbert Leader United States of America New York 14845 Horseheads Flint Road 3187 (72) Inventor Harry Jay Stevens New York, United States 14830 Corning Martin Hill Road 1512

Claims (8)

[Claims] 1. A method of making a flat glass sheet comprising the step of moving a laser beam across the glass sheet to form cracks across the glass sheet, the laser beam having an elongated beam spot on the glass sheet, A method for manufacturing a flat glass sheet, wherein the beam spot has a longest dimension of 20 mm or more. 2. The method of manufacturing a flat glass sheet according to claim 1, wherein the moving step includes a step of moving the laser beam with respect to the glass sheet at a speed of at least 300 mm / sec. 3. The moving step is at least 300 mm
2. The method for manufacturing a flat glass sheet according to claim 1, comprising the step of moving the laser beam having a beam spot whose longest axis has a length of about 10% or more of the speed at a speed of / sec. 4. The laser beam in the moving step,
The method for producing a flat glass sheet according to claim 1, wherein the flat glass sheet comprises a non-Gaussian component. 5. A method for dividing a glass substrate having a thickness of 0.4 mm to 3.0 mm used in a flat panel display, the method using a flat glass sheet having a thickness of about 0.4 mm to 3.0 mm. And a moving step of moving a laser beam on the glass sheet at a speed of at least 300 mm / sec, the laser beam having an elongated beam spot on the glass sheet, the beam spot having a longest dimension of 20 mm or more. The method for dividing a glass substrate according to claim 1, wherein cracks are formed sufficiently across the glass sheet by the moving step. 6. The method of dividing a glass substrate according to claim 5, wherein the moving step includes a step of moving a laser beam having a beam spot having a longest dimension of about 30 mm or more. 7. The glass substrate according to claim 5, wherein the moving step includes a step of moving the laser beam having a beam spot whose longest axis is about 10% or more of the velocity. How to divide. 8. The glass substrate dividing method according to claim 5, wherein the laser beam in the moving step comprises a non-Gaussian component.