KR100514099B1 - Laser cutting device and cutting method - Google Patents

Abstract

The present invention discloses a cutting device using a laser having a preliminary cutting groove forming device for forming a preliminary cutting groove at an intersection of both ends and a cutting line at which the cutting line starts. The cutting device of the present invention is used to cut a mother glass substrate in a bonded state for a liquid crystal display panel, and is provided at a laser beam for irradiating a laser beam of a specific wavelength, and at the front end of the laser, at the start end of the cutting line and the end end of the cutting line. And a preliminary cutting groove forming device for forming the starting cutting groove and the finishing cutting groove, respectively.

Description

Laser cutting device and cutting method

The present invention relates to a cutter using a laser, and more particularly, to a cutter for cutting a mother glass substrate for a liquid crystal display panel in a bonded state using a laser beam.

Liquid crystal displays (hereinafter referred to as LCDs) are a type of flat panel display that has been in the spotlight as an alternative to cathode ray tubes (CRTs) due to the advantages of small size, light weight, and low power consumption.

The liquid crystal display includes a liquid crystal interposed between two glass substrates. The liquid crystal changes in alignment with the electric field, and serves as an optical shutter for passing and blocking incident light.

In manufacturing such a liquid crystal display, in order to increase productivity, a method of manufacturing a plurality of panels during one process has been proposed. One of them is the use of a glass substrate having an area corresponding to the area of a plurality of unit panels, for example, a parent glass substrate having an area corresponding to six unit cell areas.

When manufacturing a thin film transistor liquid crystal display device using a mother glass substrate, one of two mother glass substrates has gate lines, data lines, thin film transistors, pixel electrodes, and alignment films necessary for six unit TFT substrates. On the other substrate, color filter layers, counter electrodes, black matrices, and the like required for six unit color filter substrates are formed.

The two mother glass substrates on which the above components are formed are separated into a unit panel through an assembly process for bonding, a cutting process for separating into unit panels, a liquid crystal injection process, and an end seal process for sealing the liquid crystal inlet.

During the cutting process, the mother glass substrate bonded for accurate cutting has a scribe line which is a cutting line along the boundary of the liquid crystal display (hereinafter referred to as LCD) unit A to F as shown in FIG. line; 10) is formed. Then, as the high hardness diamond glass cutter or the like passes along the scribe line 10, a precut groove having a predetermined depth is formed in the mother glass substrate 2 having a low hardness. Thereafter, a weak impact is applied to the mother glass substrate 2 to separate the unit LCD panels A to F.

However, in the cutting device using the diamond cutter, after forming the preliminary cutting grooves, the mother glass substrate must be impacted for complete division, so that the fine glass particles generated when the mother glass substrate is cut are not dispersed elsewhere. In order to prevent this, a separate dust collector is required.

In addition, the edge portion of the mother glass substrate cut into a predetermined size, as shown in the enlarged view of Figs. 2a and 2b there are a number of sharp irregularities generated when cut by the diamond glass cutter. In this sharp uneven portion, a higher stress is concentrated than the uneven portion, and in particular, a higher stress is concentrated in the portion 4 having a high degree of unevenness. Therefore, when cutting the mother glass substrate 2 by applying an impact after the formation of the preliminary cutting groove, a defect that is often cut along the high stressed portion 4 without being cut along the preliminary cutting groove portion (dotted line) is often used. Is generated.

The second problem described above also applies to a cutting device using a laser beam for cutting a substrate by irradiating a laser beam along a scribe line as well as a diamond cutter, and cooling a portion to which the laser beam is irradiated to generate a crack. Can be.

On the other hand, in the cutting of the glass mother substrate using a laser beam, after completing the first full cutting along the primary cutting line 10a with a laser, the secondary cutting line 10b orthogonal to the primary cutting line 10a. Accordingly, when the secondary cutting is performed with the laser, crack propagation does not occur near the intersection point P1 of the primary cutting line 10a and the secondary cutting line 10b, and secondary cutting becomes a problem. That is, since the first cut surface cut by the laser is slippery on the surface of the cut surface, and there are no micro cracks, the cracks started at the start end of the parent glass substrate reach the intersection point P1 by the irradiation of the laser and the injection of the cooling fluid. Crack propagation stops before Therefore, it becomes impossible to cross-cut using existing laser equipment.

Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to prevent cut line defects occurring at the start and end ends of cut lines during cutting of glass substrates and panels.

Another object of the present invention is to enable the cutting of the glass substrate or panel intersecting the cutting line using a laser.

According to an aspect of the present invention for achieving the above object, a cutting device using a laser beam is provided at the front end of the laser beam traveling direction for irradiating a laser beam of a specific wavelength to a cutting object such as a bonded glass wool substrate And a prescriber for forming a cut start groove and a cut finish groove respectively at a first end at which the selection cut line begins and at a second end at which the selection cut line ends. At the rear end of the laser, a cooling unit for cooling the cutting line irradiated with the laser beam is provided. The laser, the cutting groove forming means, and the cooling means are installed in the conveying apparatus, and are conveyed to the cutting line in the selected direction according to the movement of the conveying apparatus.

According to another aspect of the invention, the cutting method using a laser beam, first detects the cutting line and the cutting start point of the cutting object. A cutting start groove of a predetermined length is formed at the start end of the cutting line according to the detection signal of the cutting line and the cutting start point. Next, the laser beam is irradiated along the cutting line, and the cutting line irradiated with the laser beam is rapidly cooled. Next, the cutting end point of the cutting object is detected. Next, a cutting finish groove is formed at an end point of the cutting line according to the cutting end point detection signal.

According to another aspect of the present invention, a method of laser cutting a cutting object having a cross cutting line first detects the first cutting line and the first cutting start point of the cutting object. The laser beam is irradiated along the primary cutting line according to the detection signal of the primary cutting line and the primary cutting start point, and the primary cutting line irradiated with the laser beam is rapidly cooled. After irradiating the laser beam along the primary cutting line and detecting the starting point of the secondary cutting line, a preliminary cutting groove is formed at the starting end of the secondary cutting line. Then, the laser beam is irradiated from the start end to the end of the secondary cut line, and the secondary cut line irradiated with the laser beam is rapidly cooled.

Here, by selectively forming a preliminary cutting groove in each of the starting end and the finishing end of the primary cutting line, and the finishing end of the secondary cutting line, due to the presence of a high stress concentration point beyond the cutting line, The occurrence of cut failures at the finish end and at the finish end of the secondary cut line is substantially prevented.

Other objects and advantages of the present invention will become apparent from the detailed description of the invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a perspective view of a cutting device 200 using the laser beam of the present invention.

In FIG. 3, the object to be cut is a liquid crystal display panel 100 in which at least two parent glass substrates having an area corresponding to six unit cell areas, that is, a thin film transistor substrate and a color filter substrate are bonded. , Reference numeral 120 denotes a cut line.

Although not shown in FIG. 3, the thin film transistor substrate includes a thin film transistor formed on the inner surface, data and gate bus lines connected to the thin film transistor, and a pixel electrode connected to the thin film transistor, and the color filter substrate includes a color filter layer formed on the inner surface. And a counter electrode.

The laser cutting device 200 is installed at the front end of the laser 220 for irradiating the laser beam along the cutting line 120 of the bonded substrate 100 and the moving direction of the laser 220, and prior to the irradiation of the laser beam. Prescriber 260, which is a cutting groove forming means for forming preliminary cutting grooves at a starting end Ps at which the Y-direction cutting line of the bonded substrate 100 starts and an ending end (not shown) at which the cutting line ends, and a laser ( It is installed at the rear end of the 220, the cooling device 240 for cooling the cutting line 120 irradiated with the laser beam, these cooling devices 240, pre-scriber 260, and the laser 220 is installed , A cooling device 240, a prescriber 260, and a transfer device 280 for moving the laser 220 in the X-axis and Y-axis directions, which are cutting line directions.

The laser 220 includes a laser oscillation unit 222 that oscillates a laser beam, a refractive lens 224 that refracts the irradiation direction of the laser beam oscillated from the laser oscillation unit 222, and a laser beam refracted by vertical movement. It includes a focusing lens group housing 226 is housed a focusing lens group for adjusting the focus of the.

As the laser oscillation unit, a yag laser, a CO ₂ laser, a laser using a diode, or the like, having an oscillation wavelength λ of about 10.6 μm and a high output of about 50 to 250 (W), may be used. Here, the output of the laser 226 reaches a glass transition temperature (Tg) in which the cutting line portion is phase-converted from a solid phase to a liquid phase when the bonded substrate to be cut is a glass substrate.

The mother glass substrate cooling device 240 is installed at the rear end of the laser 220 based on the advancing direction of the laser 220, from the cooling fluid storage unit 242 and the cooling fluid storage unit 242 in which the cooling fluid is stored. And a spray nozzle 242 for spraying the supplied cooling fluid along the cutting line 120 of the parent glass substrate 100 to which the laser beam is irradiated.

As the cooling fluid, one material selected from the group consisting of pure water, cooling oil, liquid nitrogen, and liquid helium may be used, and the cooling fluid is rapidly heated from the spray nozzle 242 at intervals of 0.1 to 0.3 seconds. Sprayed onto the substrate 100.

The prescriber 260 for forming the cutting start groove and the cutting finish groove is installed at the front end of the laser 226, and is positioned in parallel with the panel 100 in the inoperative state, and in the operating state, the panel 100 Body portion 266 that can be grafted in a direction perpendicular to the rotating shaft 262 is coupled to the rotating shaft 262 coupled to the body portion 266, the rotating shaft 262 is coupled to the rotating shaft 262 with respect to the body portion 266 The rotary saw blade 264 is rotated to a specific RPM after turning vertically downward.

Here, the rotation shaft 262 of the prescriber 260 operates according to a detection signal of a position sensor for detecting a cutting start point and a cutting end point of the parent glass substrate 100. The position sensor 290 is provided at the front end of the moving direction of the laser 226, as shown in FIGS. 4A to 4C.

The laser 220, the cooling device 240, the prescriber 260, and the position sensor 290 are mounted to the transfer device 280 and move in the X-axis direction and the Y-axis direction, which are cutting line directions.

Specifically, the laser 220, the cooling device 240, the free scriber 260, and the position sensor 290, the Y-axis along the groove-shaped rail 284 formed on the Y-axis transfer plate 282 Direction, the Y-axis feed plate 282 moves along the X-axis feed plate 232. That is, the movement in the Y-axis direction is performed by the movement of the laser 220, the cooling device 240, and the prescriber 260 in the state where the Y-axis plate 282 is fixed, but in the X-axis direction. The movement is performed by the movement of the Y-axis plate 282 along the X-axis plate 232, whereby the laser 220, the cooling device 240, and the free scriber 260 installed on the Y-axis transfer plate 282 move. To move.

4A to 4C, an auxiliary transfer plate 283 is installed on a lower surface of the Y-axis transfer plate 282, and a nozzle 244 and a laser (2) of the cooling device 240 are installed on the auxiliary transfer plate 283. The focusing lens group housing 226 of the 220 and the position sensor 290 are mounted.

A method of cutting the mother glass substrate 100 in a bonded state using the laser cutting device 200 having the above-described configuration will be described with reference to FIGS. 3, 4A to 4C and FIG. 5.

First, referring to FIG. 3 and FIG. 4A, the bonding parent glass substrate 100 for cutting is placed on a fixing plate (not shown). The laser cutting device 200 moves toward the mother glass substrate 100, and the position detecting sensor 290 installed at the front end of the focusing lens group housing 226 of the laser 220 includes a cutting line 120 and a cutting line. Detects the starting point of the parent glass substrate 100 to start 120.

As the cutting line 120 and the starting point of the cutting line are sensed, the rotation shaft 262 of the prescriber 260 rotates clockwise, so that the rotary saw blade 264 cuts the cutting line 120 of the mother glass substrate 100. ) At the start end.

The rotary saw blade 264 forms a preliminary cutting groove at the start end of the cutting line 120 by rotating at the selected RPM.

Next, referring to FIGS. 3 and 4B, after the formation of the preliminary cutting groove, the rotary saw blade 264 stops the operation, and the rotation shaft 262 rotates counterclockwise to return to the original position.

Next, the focusing lens housing 226 moves by an interval with the position sensor 290 so that the irradiation start point of the laser beam is positioned at the cutting line start end of the mother glass substrate 100 on which the preliminary cutting groove is formed. The focusing lens housing 226 then moves along the cutting line 120 while irradiating the laser beam.

At this time, the portion of the cutting line 120 of the parent glass substrate 100 irradiated with the laser beam 228 is rapidly heated to generate high stress concentration with local thermal expansion.

As described above, the mother glass substrate 100 in which local thermal expansion occurs while being locally heated is installed at the rear end of the focusing lens housing 226 and is very low than the heating portion temperature of the mother glass substrate 100 from the nozzle 242 which follows. The low temperature fluid is intermittently supplied at intervals of 0.1 to 0.3 seconds to rapidly cool the heated mother glass substrate 100.

High thermal stress is generated in the cutting line 120 of the rapidly cooled mother glass substrate 100 by thermal expansion and thermal contraction.

When the magnitude of the thermal stress is greater than the bonding force that bonds the glass molecules and molecules, the amorphous glass molecular structure is broken, and as the molecular structure is broken, cracks are generated along the cutting line 120 of the parent glass substrate 100.

At this time, the generation of cracks and the crack propagation direction are the same as the scanning direction of the laser beam 228, that is, perpendicular to the plane of the parent glass substrate 100, so that the mother glass substrate 100 is completely cut.

Next, referring to FIGS. 3 and 4C, while the focusing lens housing 226 proceeds while irradiating a laser beam along the Y-axis transfer plate 282, the position sensor 290 is the mother glass substrate 100. Upon detecting the end point of the cutting line 120 of the rotating shaft 262 is rotated clockwise again to form a cutting finish groove having the same shape as the cutting start groove.

After the formation of the cutting finish groove, the rotation shaft 262 is rotated counterclockwise again to return to the original position, the focusing lens housing 226 to the end point of the cutting line 120 of the parent glass substrate 100 After irradiating the laser beam, the operation is stopped.

FIG. 5 is a diagram illustrating a traveling path of the focusing lens housing 226 and the rotary saw blade 264 in the laser cutting device for cutting according to the above-described process, and reference numeral 52 denotes the traveling route of the rotary saw blade 264. Reference numeral 54 denotes a traveling path of the laser 226.

As shown in FIG. 5, the traveling path 52 of the rotary saw blade 264 is within a predetermined depth from the surface of the glass substrate 100 at the start end and the end end of the cutting line, and the glass substrate 100 at portions except both ends. The upper part spaced at a distance from the surface.

Figure 6 is a view showing another embodiment of the free scriber in the laser cutting device of the present invention, as shown in the previous embodiment, the rotary saw blade does not rotate clockwise and counterclockwise depending on the operating point, but up and down Shows the case of reciprocating motion. In FIG. 6, reference numeral 382 denotes a Y-axis transfer plate, and reference numeral 383 denotes an auxiliary transfer plate, respectively.

Referring to FIG. 6, the prescriber 370 is separately installed at the front end of the focusing lens housing 326 in the moving direction.

The prescriber 370 includes an eccentric cam 354 which is eccentrically connected to a rotational shaft of the motor 352 and a rotation shaft of the motor 352, and rotates according to a detection signal of the position sensor 390. , A push rod 356 reciprocating up and down according to the rotation of the eccentric cam 354, a rotary saw blade rod 358 reciprocating up and down according to the up and down movement of the push rod 356, and a push rod 356 Elastic member 359 for pushing the rotary saw blade rod 358 pressed downward by upward) and the rotary saw blade 364 connected to the end of the rotary saw blade rod 358 to rotate at a specific RPM and the One component includes a housing 350 installed therein.

As shown in FIG. 6, the rotary saw blade rod 358 may be configured to be divided into a first rod pressurized by the push rod 356 and a second rod fixed perpendicular to an end of the first rod. However, it is also possible to use an integrated structure in the form of "a".

The eccentric cam 354 has an elliptic plate shape to press the upper end of the push rod 356 as shown in FIGS. 7A and 7B and has an axis deflected from the central axis to the longitudinal direction.

While the focusing lens housing 326 moves toward one side of the parent glass substrate 100 in the bonded state, when the position sensor 390 installed at the front end of the laser 326 detects the start end of the cutting line, the motor ( 352 rotates at a predetermined angle. As shown in FIG. 7A, the rotation of the motor 352 causes the eccentric cam 354 to press the push rod 356 at one end far from the eccentric shaft, so that the rotary saw blade rod 368 starts the cutting line. Move down towards the end. When the rotary saw blade 364 touches the parent glass substrate 100, the rotary saw blade 364 rotates at a specific RPM to form a preliminary cutting groove at the start end of the cutting line.

After the formation of the preliminary cutting groove, as the motor 352 rotates again, as shown in FIG. 7B, the eccentric cam 354 rotates so that one end close to the eccentric shaft presses the push rod 356. In response to the rotation of the eccentric cam 354, the elastic member 359 pushes the rotary saw blade rod 368 upward with a repulsive force, and the rotary saw blade 364 is separated from the mother glass substrate 100.

When the focusing lens group housing 326 moves by the distance S1 between the beam emission axis of the laser 326 from the detection position at the start end of the cut line of the position sensor 390, the laser 326 irradiates the laser beam. To start.

As in the previous embodiment, the nozzle 344 provided at the rear end of the moving plate 383 distributes the coolant along the irradiation path of the laser beam.

When the moving position detecting sensor 390 detects the end of the cutting line, the motor 352 rotates again to make the eccentric cam 352 as shown in FIG. 7A, and rotates downward toward the mother glass substrate 100. The saw blade 364 forms a finishing groove.

When the focusing lens housing 326 is moved by the distance S1 between the beam exit axis of the laser 326 from the detection position at the end of the cut line end of the position sensor 390, the laser 326 performs irradiation of the laser beam. Stop

At the same time as the end of the laser beam exiting operation of the laser 326, the nozzle 342 stops the spraying operation of the coolant.

On the other hand, the cutting surface in the Y-axis direction is complete, the cutting is completed in the above process. Therefore, when performing secondary cutting in a laser in the X-axis direction orthogonal to the Y-axis direction, a preliminary cutting groove is formed at the intersection so as to prevent the propagation of the cracks in front of the intersection.

8 and 9 are flowcharts illustrating a process of cutting using the laser cutting device when there is a cross cutting line perpendicular to each other.

Referring to FIG. 8, first, the cutting start grooves 125 and 127 of the "+" shape shown in FIG. 10 or circular shape shown in FIG. 11 are formed at an intersection point (ST81). Then, a cutting start groove is formed at the start end of the primary cutting line 120a (ST82), and the primary cutting line 120a irradiated with the laser beam while irradiating the laser beam along the primary cutting line 120a. ) Is rapidly cooled, a cutting finish groove is formed at the finishing end of the primary cutting line 120a, and the primary cutting is completed by irradiating a laser beam to the finishing end of the primary cutting line 120a ( ST83). After the first cutting, a cutting start groove is formed at the start end of the second cutting, and the second cutting line irradiated with the laser beam is irradiated with the laser beam along the second cutting line 120b orthogonal to the first cutting line ( 120b) is rapidly cooled, a cutting finish groove is formed at the finishing end of the second cutting line 120b past the intersection point, and the secondary cutting is performed by irradiating a laser beam to the finishing end of the second cutting line 120b. To complete (ST84).

According to the above method, while the crack propagates along the secondary cutting line 120b, even if it meets the intersection, since the intersection cutting start groove is formed at the intersection, the crack has linearity, and thus the crack of the secondary cutting line 120b It propagates to the finish end.

Meanwhile, the method of FIG. 9 is applied when the primary cutting line does not extend to both ends of the cutting object as shown in FIG. 2, and as shown in FIG. 12, the end point of the primary cutting line ends at a predetermined position inside the cutting object. Can be.

9 and 12, first, a cutting start groove 142 is formed at a start end of the primary cutting line 144 (ST91). Then, the laser beam is irradiated along the primary cutting line 144 and at the same time, the primary cutting line 144 irradiated with the laser beam is rapidly cooled, and a cutting finish groove ( 146 is formed, and the primary cutting is completed by irradiating a laser beam to the finishing end of the primary cutting line 144. After completion of the primary cutting, the direction of the rotary saw blade of the prescriber is rotated 90 degrees to form a cutting start groove 148 at the start end of the secondary cutting line, and the secondary cutting perpendicular to the primary cutting line 144. The secondary cutting is completed by irradiating the laser beam along the line 149 and rapidly cooling the secondary cutting line 149 irradiated with the laser beam.

According to the above method, before the laser beam is irradiated along the secondary cutting line 149, since the cutting start groove 148 is formed at the start end of the secondary cutting line 149, the crack has a linearity, 2 It propagates to the finishing end of the secondary cut line 149. Optionally, if the finishing end of the secondary cutting line 149 is as smooth as the cutting plane cut by the laser, a cutting finishing groove is formed at the finishing end of the secondary cutting line 149 and then the laser beam is cut into the secondary cutting line. Irradiate to the finish end of 149.

Meanwhile, the cutting start grooves and the cutting finish grooves in the first cutting line and the second cutting line mentioned in FIGS. 8 to 12 are formed by using a rotary saw blade made of diamond or tungsten mentioned in the previous step, or a cooling process. Two methods of generating blind scribes that do not work are applicable.

When the cutting of the mother glass substrate on one side of the bonded substrate is completed through the above process, the bonding substrate is turned over, and the other mother glass substrate is cut in the same manner.

Meanwhile, in the above-described embodiments, the cutting object has been described as an example in which the thin film transistor substrate and the color filter substrate are bonded, but the cutting object is not limited thereto. That is, all kinds of substrates having low toughness, for example, silicon substrates, which are likely to have cracks at the start end and the end end of the cutting line, may also be applied to the cutting device using the laser beam of the present invention.

In addition, in the above embodiments has been shown and described a case where the cutting device is cutting the cutting object while transporting, the cutting device is in a fixed state, it is also possible to perform the cutting while the plate supporting the cutting object. That is, it is possible to irradiate a laser beam along the cutting line of a cutting object by changing the relative position of a laser and a cutting object.

As described above, the cutting device of the present invention includes a preliminary cutting groove forming device at the start of cutting and the end of the cutting of the mother glass substrate for cutting, and before the laser beam is irradiated to the cutting line, By forming, cutting to a position other than the cut line at the end of the cut line can be substantially prevented.

In addition, even when the cutting line crosses perpendicularly, the cutting start groove is formed at the start end of the secondary cutting line, thereby enabling the application of the laser cutting device to the cutting object having the cross cutting line.

In addition, by using the position sensor to precisely control the formation of the preliminary cutting groove and the exit point of the laser beam, it is possible to prevent unnecessary use of power and waste of the coolant.

Although specific embodiments of the present invention have been illustrated and described herein, modifications and variations will be apparent to those of ordinary skill in the art. Accordingly, the following claims are intended to embrace all such alterations and modifications without departing from the spirit and scope of the invention.

1 is a plan view of a mother glass substrate.

2A is an enlarged view of a portion E1 in FIG. 1.

FIG. 2B is an enlarged view of portion E2 of FIG. 1.

3 is a schematic perspective view of a cutting device according to an embodiment of the present invention.

4A to 4C are explanatory views illustrating a process of cutting a mother glass substrate using the cutting device of FIG. 3.

5 is a cross-sectional view illustrating a path of a laser beam and a preliminary cutting groove forming apparatus in the glass substrate cut by the cutting device of FIG.

6 is a partial cross-sectional view of a cutting device using a laser beam according to another embodiment of the present invention.

7A and 7B are explanatory views for explaining the operation of the cutting device of Fig. 6;

8 and 9 is a process flow diagram showing a cutting method using a laser beam according to another embodiment of the present invention.

10 and 11 are partial plan views of cutting objects for explaining the method of FIG. 8;

12 is a partial plan view of a cutting object for explaining the method of FIG. 9;

Claims (23)

A laser for irradiating a laser beam of a specific wavelength along a cutting target line of the cutting object; Cutting groove forming means for forming a cutting groove before the laser beam is irradiated at a selected position of the cutting object to which the laser is irradiated; And And a cooling means for cooling the cutting line of the cutting object to which the laser beam of the laser is irradiated. According to claim 1, The laser and the cutting groove forming means is mounted, the cutting device using a laser beam, characterized in that it further comprises a transfer means for transferring the laser and the cutting groove forming means in a selection direction. According to claim 1, wherein the cutting groove forming means is a cutting device using a laser beam, characterized in that for further forming a cutting finishing groove at the edge of the cutting groove ends. The cutting device according to claim 1, wherein the cutting object is a glass substrate for two liquid crystal displays in a bonded state. The cutting device according to claim 4, wherein the two glass substrates are parent glass substrates having an area corresponding to at least two unit panel areas. According to claim 1, wherein the cutting groove forming means, A first rod provided at a front end of the laser in the advancing direction; A second rod pivotally coupled with the first rod to rotate clockwise and counterclockwise; And a rotary saw blade provided at an end of the second rod to form a preliminary cutting groove in a cutting line of the cutting object. According to claim 6, It is installed in the front end of the laser, and detects the position of the cutting start end and the cutting end of the cutting object, and further comprising a position sensor for indicating the operation time of the cutting means. Cutting device using a laser beam. The cutting device according to claim 1, wherein the laser is one selected from the group consisting of a yag laser, a CO2 laser, and a diode laser. Detecting a cutting line and a cutting start point of the cutting object; Forming a cut start groove of a predetermined length at a start end of the cut line according to a detection signal of the cut line and the cut start point; And And irradiating a laser beam from the cut start groove to the cut end point of the cut line, and rapidly cooling the cut line to which the laser beam is irradiated. 10. The method of claim 9, further comprising: detecting a cutting end point of the cutting object during the irradiation of the laser beam, and forming a cutting finish groove at a finish end of the cutting line. Way. 10. The method of claim 9, wherein the cutting object is a glass substrate for two liquid crystal displays in a bonded state. 12. The cutting method according to claim 11, wherein the two glass substrates are parent glass substrates having an area corresponding to at least two unit panel areas. A method of cutting a cutting object having a primary cutting line and a secondary cutting line perpendicular to each other, Sensing a first cutting line and a first cutting start point of the cutting object, and forming a cutting start groove at a start end of the first cutting line; Irradiating a laser beam along the primary cutting line starting with the cutting start groove, and rapidly cooling the primary cutting line irradiated with the laser beam; Sensing a second cut start point of the second cut line and forming a cut start groove at a start end of the second cut line; And Irradiating a laser beam along the secondary cutting line starting from the starting start groove of the secondary cutting line, and rapidly cooling the secondary cutting line to which the laser beam is irradiated. Cutting method. 15. The method of claim 13, Before the step of forming the secondary cutting start groove, further comprising the step of forming a cutting closing groove in the end of the first cutting line by detecting the end point of the primary cutting line. Cutting method using a laser. 15. The method of claim 14, further comprising, during irradiation of the laser beam to the secondary cutting line, sensing a finishing end of the secondary cutting line to form a cutting finishing groove at the finishing end of the secondary cutting line. Cutting method using a laser, characterized in that. The method according to claim 15, wherein the cutting object is a glass substrate for two liquid crystal displays in a bonded state. A method of cutting a cutting object having a primary cutting line and a secondary cutting line perpendicular to each other, Forming a preliminary cutting groove at an intersection point of the first cutting line and the second cutting line; Sensing a first cutting line and a first cutting start point of the cutting object, and forming a cutting start groove at a start end of the first cutting line; Irradiating a laser beam along the primary cutting line starting with the cutting start groove, and rapidly cooling the primary cutting line irradiated with the laser beam; Detecting the secondary cutting start point of the secondary cutting line, and irradiating a laser beam along the secondary cutting line starting from the starting start groove of the secondary cutting line, and rapidly the secondary cutting line irradiated with the laser beam Cutting method using a laser beam comprising the step of cooling. 18. The method of claim 17, Before the forming of the secondary cutting start groove, further comprising the step of forming a cutting closing groove in the end of the first cutting line by detecting the end point of the first cutting line. Cutting method using a laser beam. 19. The method of claim 18, further comprising: sensing the end of the second cut line during irradiation of the laser beam to the second cut line, thereby forming a cut end groove in the end of the secondary cut line. Cutting method using a laser beam, characterized in that. 18. The cutting method according to claim 17, wherein the preliminary cutting grooves formed at the intersection points have a "+" shape orthogonal to the intersection points. 18. The method of claim 17, wherein the preliminary cutting grooves formed at the intersections have a circular shape. 18. The method of claim 17, wherein each of the preliminary cutting grooves is formed by irradiating a laser beam without a cooling process. 20. The method of claim 19, wherein each of the preliminary cutting grooves is formed by using a rotary saw blade.