WO2005099980A1

WO2005099980A1 - Method of cutting nonmetal

Info

Publication number: WO2005099980A1
Application number: PCT/KR2005/001080
Authority: WO
Inventors: Kyu Yong Bang; Do Hyun Ryu; Chang Bok Lee
Original assignee: Top Engineering Co., Ltd
Priority date: 2004-04-14
Filing date: 2005-04-14
Publication date: 2005-10-27
Also published as: KR20050100734A; TW200602146A

Abstract

The present invention provides a method of cutting nonmetal including glass stably, by which the glass substrate for fabricating a module of a display such as TFT-LCD, PDP and OLED can be cut fast and stably with precision without causing a damage to the substrate to enhance productivity and throughput. The present invention includes the steps of generating a laser beam by an Nd-YAG oscillator (10) using a laser diode as a light source, converting the laser beam generated from the Nd-YAG laser oscillator (10) to a short wavelength of a 200~400nm UV area by a wavelength converter, converting the laser beam generated from the Nd-YAG laser oscillator (10) the short wavelength to the laser beam having an ultra short pulse of 1~100ns through Q-switching, guiding the laser beam to a torch (6), condensing to apply the guided short wavelength laser beam to a specific location on a nonmetallic substrate, and allowing the substrate and the laser beam to make relative movements to cut the substrate into a predetermined shape.

Description

Method of Cutting Nonmetal

[Technical Field]

The present invention relates to a method of cutting a substrate of a flat panel display

device, and more particularly, to a method of cutting a glass substrate, by which the glass

substrate for fabricating such a flat panel display device as TFT-LCD, PDP, OLED and the

like can be cut quickly and stably with precision without causing a damage to the substrate

to enhance productivity and throughput.

[Background Art] Generally, in fabricating such a flat panel display device as TFT-LCD, PDP, PLED and the

like, it is necessary to cut a glass substrate to fit each module size after completion of a

boding process of a cell process.

As a glass cutting method according to a related art, there is a cutting method using a

mechanical instrument such as a diamond wheel. In this case, the mechanical instrument

occupies too large space and the corresponding process is complicated to lower productivity.

As another cutting method according to a related art, there is a laser cutting method

consisting the steps of forming a primary micro-crack at a point where a scribe line starts,

heating a glass using a heating beam of CO2 laser, and then cooling down the heated portion

of the glass fast using a quencher to induce a secondary crack due to instant thermal

transformation.

In the above-explained two kinds ofthe cutting methods, an instrument for the laser cutting

method according to a related art is schematically explained as follows. First of all, a laser cutter according to a related art consists of a support or table supporting a

glass substrate to be cut, an auxiliary cracker forming an auxiliary crack coinciding with a

cutting direction ofthe substrate, an optical heating system heating the substrate by applying

a heating beam to the substrate along a scribe line, and a quencher generating a crack by

quenching the portion heated by the optical heating system.

Glass cuttmg using the related art laser cutter consists of an auxiliary crack forming step

using a wheel, a heating step according to the auxiliary crack, a cutting-crack forming step

through quick-freeze using a quencher moving in the same direction to spray refrigerants

such as He(Helium), a re-irradiation step of a laser beam for scribe, and a re-quenching step.

A detailed configuration and operation ofthe related art laser cutter are described in Korean

Patent Application Laid-OpenNo. 2002-88258.

However, the above-explained related art laser cutter needs various unstable parts including

the crack generating means for generating the primary micro-crack, the laser beam generator,

the quencher and the like, whereby the system configuration ofthe cutter is complicated.

And, the related art laser cutting method fails in forming a straight glass cutting line that

proceeds from the primary crack, whereby throughput in productivity is lowered.

Specifically, in the heating and quick-free steps of the related art laser cutting method, a

glass cutting speed is limited to execute a cutting work at low speed, whereby productivity

becomes too low. Hence, the related art laser cutting method is not suitable for the

substantial application to the product line ofthe flat panel display device. [Disclosure] [Technical Problem] Accordingly, the present invention is directed to a method of cutting nonmetal that

substantially obviates one or more problems due to limitations and disadvantages of the

related art.

An object ofthe present invention is to provide a method of cutting a substrate in fabricating

a flat panel display device, by which substrate damage is minimized in fabricating a display

module such as TFT-LCD, PDP, OLED and the like and by which quick and precise cutting

is enabled to raise productivity and product throughput.

Additional advantages, objects, and features of the invention will be set forth in part in the

description which follows and in part will become apparent to those having ordinary skill in

the art upon examination ofthe following or may be learned from practice ofthe invention.

The objectives and other advantages of the invention may be realized and attained by the

structure particularly pointed out in the written description and claims hereof as well as the

appended drawings. [Technical Solution] To achieve these objects and other advantages and in accordance with the purpose of the

invention, as embodied and broadly described herein, a method of cutting nonmetal

according to the present invention comprising the steps of: generating a laser beam by a

laser oscillator; converting the laser beam generated f om the laser oscillator to a short

wavelength of a 200~400nm UN area by a wavelength converter; and applying the laser

beam to a nonmetallic substrate to cut into a predetermined shape.

In another aspect of the present invention, a method of cutting nonmetal according to the

present invention includes the steps of generating a laser beam by an Νd-YAG oscillator using a laser diode as a light source, converting the laser beam generated from the Nd-YAG

laser oscillator to a short wavelength of a 200~400nm UV area by a wavelength converter,

converting the laser beam generated from the Nd-YAG laser oscillator the short wavelength

to the laser beam having an ultra short pulse of 1-100ns through Q-switching, guiding the

laser beam to a torch, condensing to apply the guided short wavelength laser beam to a

specific location on a nonmetallic substrate, and allowing the substrate and the laser beam to

make relative movements to cut the substrate into a predetermined shape.

[Advantageous Effects]

Accordingly, the present invention enables high-speed cutting in cutting the substrate,

thereby raising the productivity.

And, the present invention enables the high-speed and high-precision cutting in cutting the

substrate, thereby considerably reducing the failure occurrence ofthe substrate.

Specifically, the present invention secures the stability in cutting the substrate despite an

increased size ofthe substrate and reduces the working time.

It will be apparent to those skilled in the art that various modifications and variations can be

made in the present invention. Thus, it is intended that the present invention covers the

modifications and variations of this invention provided they come within the scope of the

appended claims and their equivalents. [Best Mode] The accompanying drawings, which are included to provide a further understanding ofthe

invention and are incorporated in and constitute a part of this application, illustrate

embodiment(s) of the invention and together with the description serve to explain the principle ofthe invention. In the drawings:

FIG. 1 is a perspective diagram of a substrate cutting apparatus to implement a method of

cutting a substrate in fabricating a flat panel display device according to one embodiment of

the present invention; and

FIG. 2 is a block diagram of a UN short wavelength laser beam generator in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments ofthe present invention,

examples of which are illustrated in the accompanying drawings. Wherever possible, the

same reference numbers will be used throughout the drawings to refer to the same or like

parts.

FIG. 1 is a perspective diagram of a substrate cuttmg apparatus to implement a method of

the present invention.

Referring to FIG. 1, an apparatus for cutting a substrate for fabricating a flat panel display

device includes a table 2 provided to a central portion of a base 1 to support a glass substrate

(not shown in the drawing), back-and-forth guide columns 4 provided to both sides of the

table 2, respectively, and a linear motor & mover 5 provided to each of the back-and-forth

guide column 4.

A right-to-left guide column 3 is provided to each ofthe movers 5 to guide a movement of a

torch 6 in right-to-lert directions. And, a linear motor & mover separate from the former

linear motor & mover 5 provided on the back-and-forth guide column 4 is provided to the right-to-left guide column 3.

A torch mount block 7 is mounted on the mover on the right-to-left guide column 3 so that

the torch 6 can be mounted on the mover. And, the torch 6, which condenses a UV short

wavelength laser beam to apply to a prescribed area ofthe glass substrate, is mounted on the

torch mount block 7.

And, in the substrate cutting method according to the embodiment of the present invention,

the substrate cutting apparatus further includes an optical system 11 guiding a laser beam

toward the torch 6 and a laser beam generator 10 generating the UV short wavelength layer

beam.

Preferably, at least two torches 6 are provided to enhance a cutting speed. In this case, a

spectroscope is provided to an optical path of the optical system 11 guiding the laser beam

toward the torch 6 to allow the laser beam to be applied via each ofthe torches 6 by splitting

a beam path.

In the above-explained configuration, the substrate put on the table 2 is cut by the relative

movement ofthe torch(s) 6 and the UV short wavelength laser beam while staying still. Yet,

a configuration of a relative moving means for cutting the substrate by allowing the

substrate and the laser beam to make relative movements mutually is not limited to the

above-explained example.

Alternatively, unlike the former configuration, the table 2 can move back-and-forth and

right-to-left directions to perform the glass substrate cutting work while the torch(s) 6

remains still.

Meanwhile, the laser beam generator 10, as shown in FIG. 2, includes a laser oscillator of Nd-YAG medium, a laser diode providing a exciting light source to the laser oscillator, and

a wavelength converter converting a wavelength of a laser beam generated from the laser

oscillator to a short wavelength.

The laser beam having a long wavelength coming through the Nd-YAG medium is

converted to a UV short wavelength of 200~400nm via crystal operative in wavelength

conversion.

Meanwhile, a frequency of the laser beam is at least lOKHz and is preferably 10~30KHz.

Of course, the frequency ofthe laser beam can exceed 30KHz under the circumstances.

For reference, YAG corresponds to Yttrium, Aluminum and Garnet used in manufacturing

an oscillator for leaser beam generation. Nd (neodymium: atomic No. 60, atomic weight

144.2) is added to YAG to form Nd-YAG.

A process of cutting a glass substrate in a flat panel display device using the above-

configured substrate cutting apparatus according to the present invention is explained as

follows.

First of all, in fabricating a display device such as TFT-LCD, PDP, PLED and the like, a

substrate cutting step is carried out after substrates have been bonded together.

The substrate includes a plurality of unit cells on a disc type glass substrate and needs to be

cut into a plurality ofthe unit cells.

For this, the glass substrate is loaded from outside on a mountable table 2 by a carrier robot

and the like.

The substrate put on the table 2 is horizontally fixed to by a support (not shown in the

drawing) provided to the table 2 or a multitude of vacuum holes formed at the table 2 to be stably supported.

Subsequently, a relative disposition between the substrate and a laser beam to be applied

thereto is corrected so that the substrate fixed to the table 2 can be cut into a specific form.

In correcting the relative disposition, an image recognizer (e.g., vision camera) recognizes

to confirm a location of a correction mark formed on the substrate and the torch 6 from

which the laser beam is irradiated is relatively moved against the table 2 to correct the

relative disposition.

In the location confirmation ofthe laser beam, a test laser beam is applied to a dummy glass

to form a laser beam trace thereon and the laser beam trace is then grasped using the image

recognizer such as a vision camera or a location ofthe torch 6 from which the laser beam is

irradiated is then recognized using the image recognizer provided under the torch 6.

Meanwhile, after the relative disposition between the substrate and the laser beam has been

corrected, the substrate and the laser beam are relatively moved to cut the substrate into a

specific shape.

Namely, the laser beam generated from the laser oscillator using Nd-YAG as a medium is

provided to the torch 6 as a condensing part ofthe laser beam via the optical system 11 to be

applied to a predetermined location on the substrate. In doing so, the table 2 having the

substrate mounted thereon is fixed instead of being moved, whereas the torch 6 is moved.

As a result, the substrate is cut by the movement ofthe laser beam.

In this case, the laser beam generated from the laser oscillator uses the laser diode as a light

source. The generated laser beam changes it path via the optical system 11 including a

plurality of mirrors and the like to be provided to the torch 6 as a laser beam condensing part. Since the torch 6 and the mirrors of the optical system 11 that send the laser beam .

toward the torch 6 are moved horizontally and simultaneously, the UV short wavelength

laser beam is applied to the substrate regardless of the location variation of the torch 6.

Therefore, the substrate can be cut into a designed shape.

In this case, the wavelength of the light generated from the diode as the light source is

provided to the Nd-YAG medium to be excited by a gain medium so that the laser of

l.OOOnm can be oscillated. The oscillated laser is passed through the wavelength conversion

crystal to be oscillated as the short wavelength of 200~400nm.

Thus, the laser is converted to the short wavelength to use. By using the UV short

wavelength, this is to minimize the product breakage due to thermal transformation induced

by the long wavelength when the laser beam is applied to the nonmetallic substance such as

the glass substrate and the like to be cut.

Besides, to raise energy of the laser beam, Q-switching is optically performed using an

optical resonator to generate an ultra-short pulse of 1~100 nanoseconds (ns).

To raise a cutting speed, a frequency over several KHz is generated to apply the laser beam.

If so, clear cutting can be achieved even if a moving speed of the torch 6 or the table 2 is

high.

Meanwhile, in cutting the glass substrate substantially to cut the substrate into unit cells in

the back-and-forth direction, the substrate can be cut in the back-and-forth direction in a

manner that the laser beam is applied via the torch 6 while the right-to-left guide column 3

is moved in the back-and-forth direction by a guidance of the back-and-forth guide column

4 due to the action ofthe linear motor. And, in cutting the glass substrate substantially to cut the substrate into unit cells in the right-to-left direction, the substrate can be cut in the right-to-left direction in a manner that the laser beam is applied via the torch 6 while the torch mount block 7 and the torch 6 mounted on the block 7 are moved in the right-to-left direction by a guidance ofthe right-to- left guide column 3 due to the action of the linear motor provided to the right-to-left guide column 3.

Thus, as the UV short wavelength laser beam alternately repeats the back-and-forth and right-to-left movements so that the respective cells on the glass substrate can be separated from each other individually and completely. Q-switching optically performed to raise the energy of the laser beam and the optical resonator applied to Q-switching are explained for reference in the following.

^■ First of all, a gain of a laser medium in a normal oscillation mode corresponds to a value barely exceeding a loss including an output drive-out component. In doing so, by increasing an inversion distribution quantity to exceed a threshold, it is able to obtain a more powerful laser beam.

Specifically, a loss of the optical resonator is raised to increase the inversion distribution quantity to exceed an oscillation threshold. Namely, a Q value is lowered. Thus, after the Q value has been artificially lowered, if the Q value is raised when the inversion distribution quantity has a predetermined high value, a gain coefficient becomes much higher than the oscillation threshold to bring about the oscillation of the powerful laser beam. Such a technique is called Q-switching. Meanwhile, in the optical resonator, since it is unable to make an efficient laser beam with the amplification of beam by induction discharge, parallel mirrors enabling beam resonance

are used.

If the induction discharge occurs while the inversion distribution continues and if the beam

is fed back to a laser medium section by the reflective mirrors, the beam is amplified. If a

time for the beam to go and return between a pair of the mirrors becomes a multiple of an

integer, a standing wave is generated to abruptly increase the induction discharge. And, the

optical resonator has such a configuration to generate the laser beam.

[Mode for Invention]

[Industrial Applicability]

thereby raising the productivity.

increased size ofthe substrate and reduces the working time.

Claims

[CLAIMS] [Claim 1]

A method of cutting nonmetal, comprising the steps of:

generating a laser beam by a laser oscillator;

converting the laser beam generated from the laser oscillator to a short wavelength of a

200~400nm UV area by a wavelength converter; and

applying the laser beam to a nonmetallic substrate to cut into a predetermined shape.

[Claim 2]

The method of claim 1, wherein the laser oscillator is an Nd-YAG laser.

[Claim 3]

The method of claim 1, wherein a light source ofthe laser oscillator is a laser diode.

[Claim 4] The method of claim 1, wherein a minimum frequency ofthe laser beam is lOKHz.

[Claim 5] The method of claim 1 , further comprising a step of converting the short wavelength to the

laser beam having an ultra short pulse of 1-100ns through Q-switching after the laser beam

generated from the laser oscillator has been converted to the short wavelength.

[Claim 6]

A method of cutting nonmetal, comprising the steps of:

generating a laser beam by an Nd-YAG oscillator using a laser diode as a light source;

converting the laser beam generated from the Nd-YAG laser oscillator to a short wavelength

of a 200~400nm UV area by a wavelength converter; converting the laser beam generated from the Nd-YAG laser oscillator the short wavelength

to the laser beam having an ultra short pulse of l~100ns through Q-switching;

guiding the laser beam to a torch;

condensing to apply the guided short wavelength laser beam to a specific location on a

nonmetallic substrate; and

allowing the substrate and the laser beam to make relative movements to cut the substrate

into a predetermined shape.

[Claim 7]

The method of claim 6, wherein the wavelength conversion is performed using a crystal as

a medium.

[Claim 8]

The method of claim 6, wherein a wavelength of the laser beam applied via a torch is

266nm.

[Claim 9] The method of claim 6 or claim 8, wherein a frequency ofthe laser beam is in the range of

l~100KHz.

[Claim 10]

The method of claim 6, further comprising a step of splitting a beam path in the step of

guiding the laser beam toward the torch.

[Claim 11]

The method of claim 6, wherein the laser beam is converted to an ultra short pulse by

performing Q-switching on the laser beam optically to allow the laser beam to have high energy.

[Claim 12]

A method of cutting nonmetal, comprising the steps of: loading a glass substrate on a work position;

correcting a relative disposition between the substrate and a laser beam to be applied;

of a 200~400nm UV area by a wavelength converter;

to the laser beam having an ultra short pulse in the range of 1-100ns through Q-switching;

guiding the laser beam to a torch;

nonmetallic substrate; and

into a predetermined shape.

[Claim 13]

The method of claim 12, the relative disposition correcting step comprising the steps of:

recognizing a correction mark formed on the substrate as an image to confirm a

corresponding location; and

moving the torch relatively to the substrate wherein the laser beam is irradiated via the torch.

[Claim 14]

The method of claim 13, wherein a location confirmation ofthe laser beam is carried out in a manner that a test laser beam is applied to a dummy glass to form a laser beam trace

thereon and that the laser beam trace is recognized by image. [Claim 15]

The method of claim 13, a location confirmation of the laser beam is carried out in a

manner of image recognition of a location of the torch from which the laser beam is

irradiated.