KR20190075667A - Cutting Apparatus using Laser Beam - Google Patents

Abstract

A cutting apparatus using a laser beam comprises a support, a first laser irradiating unit, a cooling unit and a second laser irradiating unit. The support supports an object in which microcracks are formed at a cut start point by opening upper and lower surfaces of at least a region with a cut neat line. The first laser irradiating unit irradiates a first laser beam from the upper surface of the object and the cooling unit sprays a refrigerant. The second laser irradiating unit irradiates a second laser beam from the lower surface of the object to a cooling area of the object. According to the present invention, quality of a cutting plane can be increased and a yield can be improved.

Description

[0001] The present invention relates to a cutting apparatus using a laser beam,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting apparatus, and more particularly, to a cutting apparatus for cutting a glass substrate or the like using a laser beam.

Conventionally, amorphous nonmetallic materials have been cut using a glass cutting wheel or a chemical reaction. In recent years, however, physical and chemical processing methods using lasers have been developed and widely used in industry.

The laser processing method is a direct processing method in which a laser beam is focused using an optical system and irradiated to the base material to cause a physical-chemical reaction. This laser direct processing method is called ablation processing, which involves a photochemical reaction that cuts off the molecular unit structure of the base material.

On the other hand, there is a method of generating a thermal shock mechanism without direct processing with a laser in order to perform high quality cutting of an amorphous nonmetallic material in a laser processing method. In this thermal shock cutting method, a laser is irradiated to a non-crystalline non-metallic material along a line to be cut to heat a cut portion and then spray a coolant. Such a process causes stress on the cut portion surface, cracks are induced.

The process of cutting a glass base material by a thermal shock cutting method can be roughly divided into a half cutting process and a full cutting process.

The half-cutting process is a process of forming a scribing crack on the surface of a base material by irradiating a first laser beam (scribe beam) to a glass base material having fine cracks, which is also called a scribing process.

Since the cutting cracks formed on the surface of the glass base material do not have a depth as much as the thickness of the glass base material and the glass base material can not be completely cut, a full cutting process is used as a subsequent process for shearing the base glass material Go ahead. The full cutting process, which is also called a breaking process, completely cuts the glass base material by causing cracks in the entire glass base material by expanding the cutting cracks on the glass surface generated in the half cutting process in the depth direction of the glass base material.

The braking process includes a contact method using a physical mechanism and a non-contact method using a laser beam. The contact method utilizes a mechanism such as a bar or a roller to extend (propagate) a cutting crack in the depth direction. Apart from the scribe beam irradiation process, which forms a crack on the surface of the glass base material, the noncontact method expands the breaking crack in the depth direction by irradiating a breaking beam to the crack area in the latter half of the process.

Japanese Patent Application Laid-Open No. 2004-0064003 (Glass Cutting Apparatus), and Japanese Patent Application Laid-Open No. 2005-0044201 (usually a glass substrate cutting apparatus having a multi-focal lens) are used for performing the half cutting process and the full cutting process in one direction of the glass base material . In addition, in these prior arts, in order to enhance the expansion effect of the cutting crack, a process of spraying the refrigerant after irradiating the breaking beam in the full cutting process is also performed.

However, when the glass base material is irradiated with the breaking beam in the same direction as the scribing beam of the half cut in the full cutting process as in the prior art, external deformation occurs in the direction opposite to the direction in which the cutting crack is formed, The straightness of the line is lowered, and there is a high possibility that a cross-section crack due to collision of the two cut surfaces occurs. These defects can adversely affect the bending strength of the cut surface and can cause product failure.

Further, in the conventional art, when the half cutting process and the full cutting process are performed, the glass base material is usually fixed to a work table by a method such as vacuum. In this case, external modification of the glass base material is limited, and cutting crack formation in the half cutting process and cutting crack extension in the full cutting process can be suppressed. Particularly, in the full cutting process, outward deformation occurs on the opposite side of the upper surface irradiated with the laser beam, that is, in the lower surface direction. At this time, such outer deformation is suppressed by the process table, As a result, chips may be generated at the cut surface or the quality of the cut surface may deteriorate.

Further, in the related art, the refrigerant spraying process is performed even after the braking beam is irradiated. If the refrigerant spraying process is performed a large number of times, there is a high possibility that the glass base material or the surrounding environment is contaminated and the light loss due to the refrigerant molecules may be worried .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems,

First, in the full cutting process, external deformation occurs in the direction in which the cutting cracks are formed, that is, in the direction of the top surface of the glass base material,

Second, it is intended to provide a laser beam cutting apparatus which removes the coolant injection process after the full cutting process to reduce the possibility of contamination of the glass base material and the surrounding environment.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a laser beam cutting apparatus comprising a support, a first laser irradiation unit, a cooling unit, and a second laser irradiation unit.

The support can support an object on which fine cracks are formed at the cutting start point by opening at least the upper and lower surfaces of the region where the line is to be cut.

The first laser irradiation unit can irradiate the first laser beam onto the upper surface of the object along the line along which the object is intended to be cut.

The cooling section can jet the refrigerant to the heating region of the object heated by the first laser irradiation section on the upper surface of the object.

The second laser irradiation part can irradiate the second laser beam to the cooling area of the object cooled by the cooling part on the lower surface of the object.

The laser beam cutting apparatus according to the present invention may include a cracking unit. The cracking portion can form a fine crack in the object.

In the cutting apparatus using a laser beam according to the present invention, fine cracks can be formed on the upper surface of the object.

In the cutting apparatus using the laser beam according to the present invention, the second laser irradiating unit may pressurize the rear surface of the object with a radiation pressure so that the first laser beam and a part of the region subjected to the refrigerant treatment are swelled upward.

In the cutting apparatus using the laser beam according to the present invention, the second laser beam may be symmetrical about the line to be cut and have a width larger than the width of the first laser beam measured in the direction perpendicular to the line to be cut.

According to the cutting apparatus using the laser beam according to the present invention having the above-described structure, the cutting line region of the object to be cut is supported so as to be opened upward and downward, and the full cutting process (breaking process) It is possible to cause external deformation in the direction of the upper surface in which the upper surface is formed. As a result, the cutting quality can be improved and the yield can be improved as compared with the conventional method in which the half cutting process and the full cutting process are performed in the same direction.

More specifically, when a laser beam is irradiated on an object, an external strain (volume expansion) due to a change in the volume of the object occurs in the irradiation region of the laser beam. In this case, the direction of the external strain (volume expansion) is determined by the radiation pressure of the laser. When the breaking beam is irradiated from the lower part of the object, the expansion pressure (object upper surface tension) is generated in the upper direction. As a result, ) Can happen. As described above, the irradiation of the lower surface of the breaking beam naturally induces a cutting crack formed on the upper surface in the propagation direction, so that occurrence of chips or cracks at the cutting site can be blocked or minimized.

In addition, the laser beam cutting apparatus according to the present invention generates bending stress on an object by volume expansion and radiation pressure due to thermal energy locally applied to a certain region without depending on the stress generated on the surface or inside of the object, Since it is possible to shear, i.e., complete cut, the object only with surface tension, no cooling step is required in the full cutting process. Thus, the removal of the cooling process in the full cutting process can reduce the contamination of the object or the optical system due to the secondary use of the refrigerant.

FIG. 1 is an overall configuration diagram of a cutting apparatus using a laser beam according to the present invention.
2 is an operation front view of a cutting apparatus using a laser beam according to the present invention.
3 is an operational plan view of a cutting apparatus using a laser beam according to the present invention.
4A and 4B are partial enlarged views of an object to be cut in a cutting apparatus using a laser beam according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a front view of an apparatus for cutting a laser beam according to the present invention. FIG. 3 is a sectional view of a cutting apparatus using a laser beam according to the present invention. Fig.

In the present invention, the object is an amorphous nonmetallic material, for example, a glass substrate or the like. Hereinafter, the construction and operation of a cutting apparatus using a laser beam according to the present invention will be described by exemplifying cutting a glass substrate as a specific object.

1 to 3, a cutting apparatus using a laser beam according to the present invention includes a support 210, a first laser irradiation unit 220, a cooling unit 230, a second laser irradiation unit 240, and the like . The first laser irradiation unit 220 and the cooling unit 230 are used in the half cutting process and the second laser irradiation unit 240 is used in the full cutting process.

As shown in FIG. 1, the support table 210 supports the glass substrate 100 and can be fixed or moved in one direction. The support base 210 may be integrally formed with a spacing space vertically passing through the inside of the support base 210. Alternatively, the first support base and the second support base may be spaced apart from each other by a predetermined distance. The support table 210 may include a fixing jig for supporting and fixing the glass substrate 100, or may include a transfer plate for movement, a rail, a motor, and the like.

The supporting table 210 can support and fix a region of the glass substrate 100 where the line to be divided E is located in the spaced apart space so that the region of the glass substrate 100 to be divided, .

The glass substrate 100 can form a micro crack in advance at the cutting start point. Microcracks can be formed by using a glass cutting wheel or a laser for glass surface processing. Microcracks can have a length of 0.5 to 5 mm.

1, the first laser irradiating unit 220 irradiates the first laser beam L1 along the line along which the substrate is to be cut E on the upper surface of the glass substrate 100 to form the glass substrate 100 on the A first laser generator 221, a first reflector 222, a first lens unit 223, and the like.

The laser generated by the first laser generator 221 is reflected by the first reflector 222 and then deformed into a desired shape at the first lens unit 223 and irradiated onto the entire surface of the glass substrate 100. The first laser beam L1 can be generated by using a carbon dioxide gas laser of an infrared wavelength band. The carbon dioxide gas laser has an infrared wavelength of 10.6 mu m and has an optical absorption rate of 90% or more in an amorphous glass medium. The first laser beam L1 can be controlled to have an irradiation area of 20 to 200 mm 2 and a flat irradiation density of 0.05 to 2 joule / mm 2.

The first laser beam L1 can irradiate the glass substrate 100 while moving along the line along which the object is intended to be cut as shown in Fig. The first laser beam L1 may have the form of an elliptical line having a longer radius in the cutting progressing direction. The first laser beam L1 of this type is elongated in the direction of the line E to be cut so that the surface of the glass substrate 100 in the region to be cut E can be locally heated quickly.

1, the cooling unit 230 is configured to inject coolant from the upper surface of the glass substrate 100 into a region heated by the first laser irradiation unit 220, and the coolant is injected into the coolant injection nozzle 231, And a refrigerant recovery nozzle 232 for recovering the refrigerant.

The refrigerant supplied through the refrigerant spraying nozzle 231 may be a gas such as cooling nitrogen, water or the like, and the refrigerant recovery nozzle 232 may be a vacuum aspirator or the like.

When the cooling part 230 ejects the coolant onto the area irradiated with the first laser beam L1 along the line along which the material is to be cut E on the upper surface of the glass substrate 100, a crack depth is generated in the injection area A scribe line can be formed along the line along which the object is intended to be cut E. The depth of cut cracks formed at this time may be about 50 to 150 μm, which may be about 10 to 30% of the thickness of the glass substrate 100.

The process in which the cooling unit 230 generates a transmission crack is as follows.

When the cooling section 230 ejects the coolant onto the glass substrate 100, the surface of the glass substrate 100 on the line E to be cut, which is locally heated by the first laser beam L1, is rapidly cooled. While the surface of the glass substrate 100 is cooled by the coolant, the thermal energy transferred by the first laser beam L 1 is conducted in the downward direction of the glass substrate 100. Tensile force is generated on the surface of the glass substrate 100 due to cooling and compressive stress is generated in the glass substrate 100 by the conducted thermal energy.

A deviation occurs in the vertical gradient of the thermal gradient on the line to be cut E while heating and cooling and a change in stress due to the temperature gradient deviation between the surface and the interior generates a vertical tension on the line E to be cut on the surface . Ultimately, due to the tensile forces generated at the surface, microcracks can create a vertical scribe crack depth.

On the other hand, the compressive stress generated by the thermal stress inside the glass substrate 100 can limit the depth of vertical cutting cracks that proceed vertically downward from the surface of the glass substrate 100. Therefore, there is a limitation in the formation of cracks and the growth in the depth direction by the stress change mechanism defined within the glass substrate 100.

Cracks are generated and propagated according to the stress difference between the surface and the interior of the glass substrate 100 due to thermal stress and the direction of the surface tension due to the change in volume. This is because the glass substrate 100 on the line to be cut E has a degree of freedom Which means that it can form a normal crack depth. As a result, it is preferable that the glass substrate 100 of the line segment to be segmented, as in the present invention, is configured such that the crack depth can be effectively generated by giving a degree of freedom without fixing the glass substrate 100 to a process table or the like.

The second laser irradiation unit 240 irradiates the second laser beam L2 onto the cooling region of the glass substrate 100 on the lower surface of the glass substrate 100 as shown in Fig. A first mirror 241, a second mirror 242, a second lens unit 243, and the like.

The laser generated in the second laser generator 241 is reflected on the second mirror 242 and then deformed into a desired shape in the second lens unit 243 and irradiated to the rear surface of the glass substrate 100. The second laser beam L2 can be generated by using a carbon dioxide gas laser of an infrared wavelength band like the first laser beam L1.

As shown in Figs. 1 and 2, the second laser beam L2 can irradiate the rear surface of the glass substrate 100 along the line along which the object is intended to be cut E. The second laser beam L2 is used to cut the entirety of the glass substrate 100 in a noncontact manner, that is, complete cutting. At this time, the second laser beam L2 is incident on the rear surface of the glass substrate 100, , And a high laser radiation pressure can press the glass substrate 100 upwardly to cause the cooling region to bulge upwards though it is fine. This upward pressurization of the radiation pressure naturally causes the cutting cracks generated on the upper surface of the glass substrate 100 to grow in the depth direction, that is, the rear direction. As a result, in the region irradiated with the second laser beam L2, .

The second laser beam L2 may have a width larger than the width of the first laser beam L1 measured symmetrically about the line along which the object is intended to be cut E and which is measured perpendicularly to the line E to be cut. The length of the second laser beam L2, that is, the length in the direction of the line to be cut E may be equal to or greater than the width. The irradiation area of the second laser beam L2 may be in the range of 20 to 200 mm 2, and the volume irradiation density may be in the range of 0.1 to 0.3 joule /..

The laser beam cutting apparatus according to the present invention may include a cracking portion in which the glass substrate 100 generates micro cracks at the top surface starting point before irradiating the first laser beam L1. A laser for glass surface processing or the like can be used as the cracking portion.

4A and 4B are partial enlarged views of an object to be cut in a cutting apparatus using a laser beam according to the present invention.

As shown in FIGS. 4A and 4B, the cooling region of the glass substrate 100 is completely blown up by the second laser beam L2. The process will be described in detail as follows.

The second laser beam L2 is incident on the rear surface of the glass substrate 100 with high energy and the cooling region of the glass substrate 100 is subjected to upward force by the high laser radiation pressure, 2 laser beam L2 generates a volume change in the laser beam irradiation area while supplying thermal energy to the glass substrate 100. [ As a result, compressive stress is generated in the glass substrate 100, and at the same time, the glass substrate 100 is entirely deformed (expanded). The outer deformation direction of the glass substrate 100 is determined by the radiation pressure of the laser beam irradiated on the glass substrate 100. In the present invention, since the second laser beam L2 is irradiated on the rear surface of the glass substrate 100, (Expansion) can be made in the opposite direction to the direction to be irradiated, that is, the upward direction.

As a result, the second laser beam L2 generates the expansion pressure (the upper surface tension of the glass substrate) in the upward direction of the second glass substrate 100, and as a result, the cutting crack HC) is naturally propagated in the depth direction of the glass substrate 100, that is, in the rear direction, so that the natural shear (FC) of the glass substrate 100, that is, complete cutting can be easily caused.

In addition, in the present invention, as described above, since the second laser beam L2 generates a surface tension according to the bending stress of the glass substrate 100 to shear the glass, the cooling process involved in the conventional full cutting process is required I do not. This elimination of the cooling process can alleviate the contamination concerns of the optical system and the glass substrate 100 due to the coolant injection, and it is not necessary to consider the light loss due to the coolant molecules. Further, unlike the prior art, the present invention naturally induces a cutting crack on the upper surface in the propagation direction, that is, in the rear direction, so that there is also an advantage that chips and cracks are hardly generated in the cut portion.

Although the present invention has been described based on various embodiments, it is intended to exemplify the present invention. Those of ordinary skill in the art will appreciate that variations and modifications may be made thereto based on the above embodiments. However, since the scope of the present application is determined by the following claims, such modifications and variations can be construed as being included in the following claims.

100: glass substrate 210: support
220: first laser irradiation part 230: cooling part
240: second laser irradiation part E:
L1: first laser beam L2: second laser beam

Claims (4)

In the cutting apparatus,
A supporting base supporting at least an upper surface and a lower surface of an area where at least a line to be divided is present,
A first laser irradiating unit for irradiating a first laser beam on an upper surface of the object along the line along which the object is to be cut;
A cooling unit for spraying a coolant onto a heating region of the object heated by the first laser irradiation unit on the upper surface of the object;
And a second laser irradiating unit for irradiating a second laser beam onto a cooling area of the object cooled by the cooling unit on the lower surface of the object. The method according to claim 1,
And a cracking portion for forming the fine cracks on the object. 3. The method according to claim 1 or 2,
The fine cracks are formed on the upper surface of the object,
Wherein the second laser irradiation unit presses the rear surface of the object with a radiation pressure to swell at least a part of the region treated with the first laser beam upward. The method of claim 3,
Wherein the second laser beam is symmetrical about the line along which the object is intended to be cut and has a width larger than a width of the first laser beam measured perpendicularly to the line along which the object is intended to be cut.

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