WO2005099979A1

WO2005099979A1 - Apparatus for cutting nonmetal

Info

Publication number: WO2005099979A1
Application number: PCT/KR2005/001068
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: 2005-04-13
Publication date: 2005-10-27
Also published as: KR20050100733A; TWI275440B; TW200602147A

Abstract

The present invention provides an apparatus for 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 a laser beam generator (10) generating a UV short wavelength laser beam, an optical system (11) guiding a beam path of the short wavelength laser beam generated from the laser beam generator (10) to a portion specified for irradiation, a torch (6) condensing to apply the short wavelength laser beam to a specific location on a nonmetallic substrate to be cut, and a relative movement means for allowing the substrate and the laser beam to make a relative movement to cut the substrate.

Description

Apparatus for Cutting Nonmetal

[Technical Field]

The present invention relates to an apparatus for cutting a substrate of a flat panel display

device, and more particularly, to an apparatus for 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]

In general, 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 of the 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 of the 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 cutting 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, a re-irradiation step of a laser beam for scribe, and a re-quenching step.

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

Patent Application Laid-Open No. 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 of the 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 of the flat panel display device. [Disclosure]

[Technical Problem]

The present invention is directed to an apparatus for cutting nonmetal that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide an apparatus for cutting a substrate, 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.

[Technical Solution]

To achieve these objects and other advantages and in accordance with the purpose of the

invention, as embodied and broadly described herein, an apparatus for cutting nonmetal

according to the present invention includes a laser beam generator generating a UN short

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

specific location on a nonmetallic substrate to be cut, and a relative movement means for

allowing the substrate and the laser beam to make a relative movement to cut the substrate.

Preferably, the laser beam generator includes a laser oscillator of an Νd-YAG medium, a

laser diode providing an exciting light source to the laser oscillator, and a wavelength

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

short wavelength.

More preferably, wherein the wavelength converter is a crystal.

Preferably, a wavelength of the laser beam applied via the torch lies between 200~400nm.

Preferably, a minimum frequency of the laser beam is 1 OKHz.

Preferably, a frequency of the laser beam lies between l~100KHz.

Preferably, the apparatus further includes an optical resonator making the laser beam into an ultra short pulse by performing Q-switching on the laser beam optically to allow the laser

bean to have high energy.

Preferably, the apparatus further includes an optical system guiding a beam path of the short

wavelength laser beam generated from the laser beam generator to a portion specified for

irradiation.

It is to be understood that both the foregoing general description and the following detailed

description of the present invention are exemplary and explanatory and are intended to

provide further explanation of the invention as claimed. [Advantageous Effects] 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 of the substrate.

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

increased size of the substrate and reduces the working time.

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 of the following or may be learned from practice of the 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. [Best Mode] The accompanying drawings, which are included to provide a further understanding of the

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 of the invention. In the drawings: FIG. 1 is a perspective diagram of an apparatus

for cutting a substrate for 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.

Reference will now be made in detail to the preferred embodiments of the 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.

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

device according to one embodiment of the present invention 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 of the movers 5 to guide a movement of a

torch 6 in right-to-left 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 UN short wavelength laser beam to apply to a prescribed area of the glass substrate, is mounted on the

torch mount block 7.

And, the substrate cutting apparatus according to the present invention further includes an

optical system 11 guiding a laser, beam toward the torch 6 and a laser beam generator 10

generating the UN 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 of the 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 of the torch(s) 6 and the UN 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

Νd-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 Νd-YAG medium is converted to a UN 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.

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

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

144.2) is added to YAG to formNd-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 of the 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 of the 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 of the 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 of the 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 of the 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 UN 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,000nm 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 UN 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 of the 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 of the 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 UN 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. [Industrial Applicability]

The present invention enables high-speed cutting in cutting the substrate, thereby raising

the productivity.

increased size of the substrate and reduces the working time.

Claims

[CLAIMS]

[Claim 1]

An apparatus for cutting nonmetal, comprising:

a laser beam generator generating a UN short wavelength laser beam;

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

nonmetallic substrate to be cut; and

a relative movement means for allowing the substrate and the laser beam to make a relative

movement to cut the substrate.

[Claim 2] The apparatus of claim 1 , the laser beam generator comprising:

a laser oscillator of an Νd-YAG medium;

a laser diode providing an exciting light source to the laser oscillator; and

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

oscillator to a short wavelength.

[Claim 3]

The apparatus of claim 2, wherein the wavelength converter is a crystal.

[Claim 4]

The apparatus of claim 1, wherein a wavelength of the laser beam applied via the torch lies

between 200~400nm.

[Claim 5]

The apparatus of claim 1 or claim 4, wherein a minimum frequency of the laser beam is

lOKHz.

[Claim 6]

The apparatus of claim 1 or claim 4, wherein a frequency of the laser beam is in the range

of l~100KHz.

.

[Claim 7] The apparatus of claim 1, further comprising an optical resonator making the laser beam

into an ultra short pulse by performing Q-switching on the laser beam optically to allow the

laser beam to have high energy.

[Claim 8]

The apparatus of claim 1, further comprising an optical system guiding a beam path of the

short wavelength laser beam generated from the laser beam generator to a portion specified

for irradiation.

[Claim 9]

An apparatus for cutting nonmetal, comprising:

a table supporting a glass substrate;

a pair of back-and-forth guide columns provided to both sides of the table;

a right-to-left guide column movable in a back-and-forth direction by a guidance of the

back-and-forth guide column;

at least two torches provided movable in a right-to-left direction along the right-to-left guide

column to apply a condensed laser beam to a predetermined area of the glass substrate;

an optical system guiding the laser beam toward the at least two torches; and

a laser beam generator generating a UN short wavelength laser beam guided to the at least

two torches via the optical system.

[Claim 10]

The apparatus of claim 9, wherein a linear motor and a mover are provided onto each of

the back-and-forth and right-to-left guide columns.

[Claim 11] The apparatus of claim 9 or claim 10, wherein a torch mount block is provided onto the

mover of the right-to-left guide column to mount the torch thereon.

[Claim 12]

The apparatus of claim 9, wherein a spectroscope is provided to an optical path of the

optical system guiding the laser beam toward the torches to allow the laser beam to be

applied via each of the torches by splitting a beam path.

[Claim 13]

The apparatus of claim 9, the laser beam generator comprising:

a laser oscillator of an Nd-YAG medium;

a laser diode providing an exciting light source to the laser oscillator; and

oscillator to a short wavelength.

[Claim 14]

The apparatus of claim 13, wherein the wavelength converter is a crystal.

[Claim 15] The apparatus of claim 9, wherein a wavelength of the laser beam applied via the torch lies

between 200~400nm.

[Claim 16] The apparatus of claim 9 or claim 15, wherein a nώiimum frequency of the laser beam is

lOKHz.

[Claim 17]

The apparatus of claim 9 or claim 15, wherein a frequency of the laser beam is in the range

of l~100KHz.

[Claim 18]

The apparatus of claim 9, further comprising an optical resonator making the laser beam

laser bean to have high energy.