HK1068325B - Glass cutting method - Google Patents

Description

Method for cutting glass

Technical Field

The present invention relates to a method of cutting glass, and in particular to a method of cutting glass sheets.

Background

Glass substrates used for manufacturing flat panel displays such as liquid crystal displays, plasma displays, or electroluminescent displays are produced from glass plates (hereinafter such glass plates are referred to as "base materials") as raw materials, the size of which is larger than that of the glass substrates. The glass substrate is produced by cutting a base material. For example, for a glass substrate of a liquid crystal display applied to a 15-inch monitor, 4 substrates are obtained from a mother substrate having dimensions of 550mm × 650mm as shown in fig. 1. The glass substrate can be obtained by cutting a piece of the base material. When a glass plate having a thin film formed on the surface thereof is used as the base material, a glass substrate can be obtained by cutting it.

On the other hand, when producing a glass substrate for small-sized liquid crystal display applications, an important cutting method is to directly cut a glass substrate obtained by bonding. The reason for this is that the glass substrate used in the liquid crystal display has a structure in which two sub-glass substrates are bonded to each other with a sealant. Here, the glass substrate for liquid crystal display application has a cell 1 in which liquid crystal is sealed between two sub-glass substrates.

Cutting of parent material is disclosed in the following non-patent documents: "scribing and separating technique" of tsuitai, an addition to the manufacturing and inspection technique of the fourth-generation LCD, entitled "FPD intelligent" of the month, PP85-89, 1/20/2000, published by Press Journal inc (hereinafter referred to as "non-patent document 1"); and Shanbenjian, "a beam directing apparatus and a laser glass cutting apparatus which can be used for cleaning a room", journal FPD Intelligence, 1994, 4, PP28-31, published by Pressjournal Inc. (hereinafter referred to as "non-patent document 2"). The parent material cutting methods disclosed in non-patent documents 1 and 2 include: a scribing step of forming a scribe line on the surface of the base material; and applying a mechanical or thermal stress to the scribe line. This cutting method is called a scribing and separating method.

The cutting method described in non-patent document 1 is a general scribing and separating method. The scribing and separating method includes a scribing line forming step and a mechanical stress applying step. The scribing line forming step is a step of scribing the surface of the base material using a diamond or cemented carbide wheel cutter to form a scribing line. The depth of the scribe line formed in this step is in the range of 10 to 15% of the thickness of the base material. The mechanical stress applying step is a step of applying a mechanical stress to a scribe line formation portion. In this step, the glass substrate is cut from the base material.

The cutting method described in non-patent document 2 includes a scribe line forming step and a thermal stress applying step. This cutting method is a method employed in a glass cutting apparatus of ACCUDYNE, USA. The scribing line forming step includes the sub-steps of: (1) applying a metal foil to form small physical damage at the end of the base material; (2) irradiating the physical damage with a linear laser beam; and (3) immediately after the laser beam irradiation, spraying a mixed gas of helium and water on the base material to rapidly cool it. In the scribe line forming step, a scribe line of a molecular level is formed in the base material. The thermal stress applying step is a step of irradiating both sides of the scribe line with laser light, and then spraying a mixture of helium and water on the scribe line to cool it. By the laser beam irradiation and the immediate cooling thereafter, thermal stress is generated on the scribe line to cut out the glass substrate from the base material.

However, the following problems have not been solved in the cutting method described in non-patent document 1. The first problem is that cracks are generated on and near the surface of the base material when forming the scribe line. Cracks are easily introduced to the glass fragments both during scribing and cutting. A second problem is that, when a plurality of scribe lines are formed, several cracks are generated at intersections between the scribe lines. Since the crack is present, the base material is likely to be broken during cutting. The strength of the edge of the glass substrate obtained by cutting is weakened due to the presence of cracks. The third problem is that in order to improve the edge strength of the glass substrate, chamfering of the glass substrate is required. In order to remove the glass powder and the like accompanying the chamfering, it is necessary to clean it. That is, this cutting method is problematic as a method of cutting a glass substrate because of low productivity.

On the other hand, the cutting method disclosed in non-patent document 2 has been expected to have high productivity because it is unnecessary to perform a cleaning process or a chamfering process after cutting. However, in this cutting method, the problems have not been solved because of low cutting accuracy and reduced speed in the cutting process. Worse still, the cutting device from ACCUDYNE company disclosed in non-patent document 2 is expensive, and therefore, the device cannot be widely used in general applications.

It is known that glass breakage occurs due to fine physical damage originally present on the surface of the parent material. Therefore, as the physical damage of the surface on the surface of the glass substrate itself is reduced, the glass strength can be further improved, which further contributes to preventing the occurrence of glass breakage. When the polishing process is applied, it removes physical damage on the surface of the glass substrate, but reduces productivity in cutting the glass substrate. On the other hand, if the physical damage on the glass surface can be reduced during the parent material cutting process, the productivity in cutting the glass substrate is not lowered. It is therefore desirable to propose a technique for reducing physical damage on the surface of the parent material during the cutting process.

Disclosure of Invention

An object of the present invention is to provide a method of cutting glass, which suppresses generation of glass chips and cracks in the glass, thereby obtaining a glass substrate with high dimensional accuracy. Another object of the present invention is to provide a method of cutting glass, which can remove a plane crack generated when forming a scribe line, or a method of cutting glass, which can form a scribe line without generating a crack.

The present invention is directed to a method of cutting glass in which score lines are formed on the surface of the glass, followed by a chemical treatment.

The present invention is also directed to a method of cutting glass, in which a mask corresponding to a cutting pattern is formed on a surface of glass, and then a chemical treatment is performed thereon to form slits corresponding to the cutting pattern thereon. According to such a method of performing the cutting of the mask, a slit (hereinafter, simply referred to as "slit") corresponding to the scribe line can be formed.

According to the present invention, even if the base material is cut by applying mechanical stress or thermal stress thereto, stress is concentrated on a scribe line or a slit (hereinafter, collectively referred to as a "scribe line or the like"). As a result, generation of glass chips or glass breakage at the time of cutting can be suppressed.

According to the present invention, the necessity of performing a step of processing a cut surface after cutting is reduced. This means cost reduction in achieving cutting of the glass substrate. Also means that the productivity of glass cutting improves. Since physical damage on the surface of the parent material without mask coating is reduced by chemical treatment, the strength of the glass substrate is improved.

In the cutting method for forming the slit, since external stress is not likely to act on the base material, there is no possibility that cracks and breakage are generated in the glass for forming the slit. Since it is possible to form slits of any shape, the glass substrate is provided with a high degree of dimensional accuracy.

Preferable examples of the method of implementing the mask include a screen printing method, a laminate film processing method, a resist coating photolithography method, and the like. The mask is preferably implemented using a mask material that is resistant to the chemical treatment solution.

The chemical treatment should be carried out by contacting the glass surface with a chemical treatment solution. The glass is preferably immersed in a chemical treatment solution.

When the base material is immersed in the chemical treatment solution at the time of chemical treatment, it is preferable to generate bubbles or a jet flow in the chemical treatment solution. At this time, the effect of stirring the chemical treatment solution can be obtained. This can prevent the products generated in the chemical treatment solution from adhering to the glass when bubbles are generated.

In the chemical treatment, the chemical treatment solution is preferably flowed along the surface of the glass. For example, the chemical treatment solution may also be flowed along the glass surface by moving bubbles and jets along the glass surface. In this case, the effect of reducing physical damage existing on the base material is increased.

In the chemical treatment, a chemical treatment solution may be flowed into a portion where a scribe line or the like is formed. For example, by flowing bubbles and a jet flow into a portion where a scribe line or the like is formed, a chemical treatment solution can be flowed into the portion where the scribe line or the like is formed. When the chemical treatment solution is flowed into a portion where a scribe line or the like is formed, a depth deepening action of the scribe line or the like increases.

The chemical treatment may be a treatment method in which a chemical treatment solution is sprayed on the glass surface, vapor of the chemical treatment solution is blown on the glass surface, or the glass surface is exposed to the vapor of the chemical treatment solution.

It is preferable that the glass is cut by applying mechanical or thermal stress to the scribe line or the like after the chemical treatment is completed.

In order to cut the glass by applying mechanical stress, it is preferable to cut the glass after the chemical treatment in such a manner that a tensile force is applied in a direction to pull the glass segments apart from each other, centering on a scribe line or the like.

In order to cut the glass by applying the mechanical stress, it is preferable that after the chemical treatment is finished, a pressure is applied in a direction either facing a surface on which the scribe line or the like is formed or a direction facing another surface opposite to the surface on which the scribe line or the like is formed, thereby applying the mechanical stress on the scribe line or the like to cut the glass. Applying pressure on a surface formed by a scribe line or the like is preferable to other methods.

In order to cut the glass by applying thermal stress, it is preferable that both sides of the scribe line or the like are irradiated with laser light after the chemical treatment is finished to cut the glass.

The invention also provides a flat panel display glass substrate produced by the cutting method.

The invention also aims at a flat panel display, which applies the glass substrate of the flat panel display.

The present invention described above can suppress cracks in glass caused by cutting a glass substrate. As a result, the dimensional accuracy of the glass substrate of the liquid crystal display can be improved. In addition, the strength of the glass substrate can be improved by reducing physical damage on the surface of the glass on which no mask is implemented.

Drawings

FIG. 1 shows a glass plate from which 4 glass substrates for a 15 inch liquid crystal display can be obtained;

FIG. 2 is a view showing the pressure cutting step of the present invention;

FIG. 3 is a schematic view showing a surface profile of a glass substrate obtained by the cutting method of the present invention observed with a microscope at a magnification of 50;

FIG. 4 is a schematic view showing a surface profile of a glass substrate obtained by cutting without chemical treatment after forming a scribe line, observed with a microscope at a magnification of 50;

FIG. 5 is a schematic view showing the profile of a cut surface of a glass substrate obtained by the cutting method of the present invention observed with a microscope at a magnification of 50;

FIG. 6 is a schematic view showing the profile of a cut surface of a glass substrate obtained by cutting without chemical treatment after forming a scribe line, observed with a microscope at a magnification of 50;

FIG. 7 schematically illustrates a glass sheet strength measurement method; while

Fig. 8 is a schematic view showing a bonded glass substrate cut by the cutting method of the present invention, as viewed from one side of the bonded glass substrate with a microscope set at a magnification of 50.

Detailed Description

Examples of the cutting method of the present invention will be given below. The glass cutting method of the present invention comprises the steps of: forming a scribe line on a surface of a base material; carrying out chemical treatment; and cutting the parent material. The cutting method of the present invention can also replace the scribe line forming step and the chemical treatment step with a slit forming step. The slit forming step may be performed in a condition where a mask is formed on the surface of the parent material and then a chemical treatment is performed, and the mask corresponds to the cutting pattern.

A single-layer glass substrate is used as glass that can be cut by the method of the present invention. When a glass substrate for a liquid crystal display is produced, a mother material in which two glass substrates are bonded to each other with a sealant may be used. The bonded glass substrate typically includes a color filter layer or the like necessary for a liquid crystal display glass substrate.

Similar to the conventional technique, the scribe line on the surface of the base material may be formed with a diamond cutter or a cemented carbide wheel cutter. The scribe line is formed by scribing a line on the base material with a diamond cutter or a cemented carbide wheel cutter.

The scribe line can be formed by the same method as that employed by a cutting device manufactured by ACCUDYNE applied with a conventional technique. That is, (1) forming physical damage on the edge of the base material by using a metal foil or the like; (2) irradiating physical damage with a linear laser beam and (3) immediately thereafter spraying a mixed gas of helium and water to the base material to rapidly cool it. After applying these three steps, a scribe line may be formed on the surface of the base material.

The slits on the surface of the base material are formed by implementing a mask on the surface of the base material followed by a chemical treatment. The mask is implemented using a mask material to correspond to the cutting pattern. The mask material is preferably not attacked by the chemical treatment solution. Examples of the mask coating method include a screen printing method, a laminated film processing method, a resist coating photolithography method, and the like.

The screen printing method is a method in which a screen is divided into portions, some of which are passed through by a masking agent and the rest of which are not passed through by the masking agent, and then the screen is brought into contact with the surface of a base material so as to extrude the masking agent passed through the portions, thereby coating a mask on the surface of glass. The laminated film processing method is a method in which a pressure-sensitive adhesive layer is formed on one surface of a film serving as a mask material, which is adhered to the surface of a base material. Resist coating photolithography is a method in which a mask is completed by coating a photosensitive resist as a mask material on the surface of a base material and then irradiating with light.

When one scribe line or the like is formed on one sub substrate of the bonded glass substrate, another scribe line or the like is usually formed on the other sub substrate, and the one scribe line or the like is usually located directly below the scribe line on the one sub substrate. When the scribe line on the other sub-substrate is not formed immediately below the scribe line, the cut surface of the bonded glass substrate has a stepped cross section in the thickness direction. When formed in such a stepped section, the lower step of the section may function as an adhesive fixing portion for adhesive fixing to another member.

The chemical treatment is performed by bringing a chemical treatment solution into contact with glass as a base material.

The chemical treatment solution should be one that contains chemicals that dissolve the glass. The chemical treatment solution is preferably an aqueous solution containing hydrofluoric acid. The aqueous hydrofluoric acid solution preferably contains one or more chemical agents selected from the group consisting of a fluoride of hydrogen, an inorganic acid and an organic acid.

Examples of hydrofluorides are ammonium fluoride, potassium fluoride and sodium fluoride. Examples of inorganic acids are hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid. Examples of organic acids are acetic acid and succinic acid. One or more anionic surfactants and amphoteric dielectric surfactants may be added to the chemical treatment solution. Sulfonate-based surfactants and the like are used as the anionic surfactant. Amine-based surfactants are used, for example, as amphoteric dielectric surfactants.

The main role of each chemical in the chemical treatment solution is as follows. The effect of hydrofluoric acid and hydrofluoride is to chemically etch the glass. And the inorganic acid, the organic acid, the anionic surfactant and the amphoteric dielectric surfactant function to prevent products generated in the chemical treatment solution from adhering to the glass surface.

The contact time between the base material and the chemical treatment solution and the temperature of the chemical treatment solution are appropriately changed depending on the composition and thickness of the base material.

The method of bringing the chemical treatment solution into contact with the base material includes the following methods (1) to (4), for example

(1) Immersing the parent metal in a chemical treatment solution,

(2) spraying a chemical treatment solution onto the base material,

(3) blowing steam of the chemical treatment solution onto the base material, and

(4) the parent material is exposed to the vapor of the chemical treatment solution.

When the mother material is immersed in the chemical treatment solution, it is preferable to generate bubbles or a jet of the chemical treatment solution therein. In order to generate the bubbles or the jet of the chemical treatment solution, it is suggested to install a bubble generator or a chemical treatment solution jet device at the bottom of the chemical treatment solution tank. In this case, the chemical treatment solution can be uniformly stirred. When installed in the bubble generator, the product in the chemical treatment solution rises to the surface thereof, thereby preventing the product from adhering to the glass.

The flow of bubbles and the jet stream are the same as the flow of chemical treatment solution. Since the physical damage on the glass surface is a recessed portion, the chemical treatment solution therein is difficult to be exposed to the flow of the chemical treatment solution. The chemical treatment solution in the recess portion is brought into a static state, so that the etching reaction speed is easily slowed down. As a result, other portions than the recessed portions are etched away before they are etched away, thereby producing an effect of reducing physical damage on the glass surface. Thus, by moving the chemical treatment solution along the glass surface, a great effect of reducing physical damage on the glass surface can be obtained. A greater effect of ensuring reduction of physical damage is achieved when the movement of the chemical treatment solution approaches a movement substantially parallel to the glass surface.

Further, an effect is produced in which the corners of the glass substrate are chamfered. This effect is obtained with chemical treatment. The chamfering effect of the corners of the glass substrate is particularly increased when the chemical treatment solution flows substantially parallel to the glass surface.

On the other hand, when the chemical treatment solution is caused to flow into the scribe line or the like forming portion, the chemical treatment solution in the scribe line or the like forming portion is brought into a flowing state, thereby increasing the etching reaction rate; therefore, the effect of deepening the scribe line or the like is increased. When the direction in which the chemical treatment solution flows into the score line or the like is substantially perpendicular to the glass surface, the deepening effect of the depth of the score line or the like is more enhanced. When the chemical treatment solution is flowed into the scribe line or the like, there is also a role of chamfering the corner of the glass substrate.

When the bubble generator or the chemical treatment solution jet device is installed on the bottom of the chemical treatment solution tank, a method of immersing the base material in the chemical treatment solution is selected from the following viewpoints.

When it is desired to increase the effect of reducing physical damage on the glass surface, the mother glass substrate is lowered into the chemical treatment solution in a direction perpendicular to the solution surface. When it is desired to increase the effect of deepening the depth of the scribe line or the like, the mother glass substrate is immersed in the chemical treatment solution in a direction parallel to the surface of the chemical treatment solution. The base material may be immersed in the chemical treatment solution obliquely with respect to the solution surface.

And cutting the base material after the chemical treatment is finished. As a cutting method, it is suggested to apply mechanical or thermal stress on the glass to cut the glass.

The cutting method using mechanical stress includes a cutting method in which a tensile force or a pressing force is applied. The tension cutting glass method is a method in which tension is applied in a direction to move glass segments away from each other centering on a scribe line or the like. The pressurizing method is a method in which pressure is applied to a scribe line or the like to cut the glass. A pressing method is preferred as the cutting method.

When the pressing method is applied, the direction in which the pressing force acts may be in a direction facing a surface where the scribe line or the like is formed, or in a direction facing another surface opposite to the surface where the scribe line or the like is formed. It is preferable to apply pressure to the surface formed by the scribe line or the like. Fig. 2 shows an example of a state where pressure is applied to a surface where a scribe line or the like is formed. The base material 2 bridges between the two support tables 4. Then, the pressing tool 5 is operated to apply a pressure to the scribe line or the like from directly above the scribe line or the like 3, thereby cutting the base material.

When pressure is applied to a surface where a scribe line or the like is formed in order to cut the base material, the pressure used to cut the base material is smaller than the pressure applied to the other surface opposite to the surface where the scribe line or the like is formed. For the base material having a shallow scribe line or the like thereon, the base material may be cut as long as the smoothness on the cut surface is maintained. For example, when a piece of alumino-borosilicate glass having dimensions of 40mm × 60mm × 0.7mm, on which slits having a depth of 200 μm are formed, is chemically treated and cut, it has been confirmed that if pressure is applied to the other surface opposite to the surface where the slits are formed, the pressure must be 3000g or more. On the other hand, it has been confirmed that if pressure is applied to the slit-formed surface, the glass can be cut with the pressure in the range of 1500g or more to 2000g or less.

That is, since less pressure is required, rapid cutting can be achieved. Since the pressure distribution is less likely to occur in the portion other than the scribe line, the glass can be prevented from cracking during cutting.

Note that the pressing means in contact with the glass may be a flat plate. Thinner plates are preferably applied.

As the thermal stress applying method, for example, a method in which both sides of a scribe line or the like are irradiated with a laser beam to cut glass has been applicable. In this case, laser heating is performed at a temperature of the glass melting temperature or lower.

Next, the present invention will be shown based on examples. It should be noted, however, that the present invention is not limited to the following examples.

(example 1)

Two glass sheets for liquid crystal display each having a size of 400mm × 500mm × 0.7mm were bonded to each other with a sealing agent. A scribe line having a depth of about 0.05mm was formed on both side surfaces of the above glass sheet by a diamond cutter. One of the scribe lines is formed to be located directly below the other scribe line. Subsequently, the thickness of the bonded glass was reduced by about 0.4mm in the chemical treatment.

The chemical treatment was performed under the following conditions.

The chemical treatment solution is an aqueous solution containing 5% hydrofluoric acid, 10% hydrochloric acid and 5% nitric acid.

The bonded glass is immersed in the chemical treatment solution and the glass is oriented in a direction perpendicular to the surface of the solution.

Bubbles are generated from the bottom of the chemical treatment solution reservoir, wherein the bubbles flow substantially parallel to the glass surface.

After the chemical treatment is completed, pressure is applied from just above the scribe line to cut the bonded glass. (comparative example 1)

The bonded glass is cut without chemical treatment. The cleavage was carried out in a similar manner as in example 1, except that no chemical treatment was carried out.

The glass substrates obtained in example 1 and comparative example 1 were observed under a microscope. Fig. 3 and 4 are schematic views obtained when observing the shape of the corner of the glass substrate in the vicinity of the intersection of the scribe lines. FIGS. 5 and 6 are schematic views obtained when observing the topography of the cut surface of the glass sheet. Fig. 3 and 5 are views for observing the glass substrate (example 1) subjected to the chemical treatment. Fig. 4 and 6 are views observed for a glass substrate (comparative example 1) which was not subjected to chemical treatment.

In fig. 3 and 4, the blackened portion is the glass substrate 3. The angular shape of the glass substrate 6 shown in fig. 3 is a state in which glass is not broken at all. On the other hand, the angular shape of the glass substrate 7 shown in fig. 4 was confirmed to have glass breakage 8. From the observation, it was found that no glass breakage was recognized at the corners of the glass substrate of example 1 subjected to the chemical treatment. On the other hand, glass breakage was recognized at the corners of the glass substrate of comparative example 1 which had not been chemically treated. Therefore, it was confirmed that, when the glass substrate was cut, cracks of the glass substrate were avoided due to the chemical treatment thereof.

The glass cut surface 9 is smooth in fig. 5. On the other hand, the glass cut surface 11 is not smooth in fig. 6, but has cracks 13 thereon.

In fig. 5, the score line 10 on the glass surface is linear. On the other hand, in fig. 6, depressions are indicated by blacking. That is, the scribe line 12 is irregular in shape, having enlarged depressions and projections. The enlarged depressions and protrusions indicate the occurrence of glass cracks and breakage when the glass substrate is cut. Therefore, it is believed that by performing the chemical treatment, the glass crack generated when the scribe line is formed is removed.

It was confirmed that in the glass flake of example 1, the shape of the corner of the portion where the scribe line was formed was chamfered. On the other hand, it was confirmed that, in the glass substrate of comparative example 1, the angular shape of the portion where the scribe line was formed was a right angle or an acute angle (not shown).

The strength of the glass substrates of example 1 and comparative example 1 was measured. The strength measurement of the glass substrate was performed under the following conditions. Fig. 7 shows a measurement method.

(1) Two glass thin plate supporting tables 15 having dimensions of 40mm (L2) × 40mm (L3) × 8.4mm (L4), which are installed in parallel with each other with a spacing (L1) of 49mm therebetween;

(2) the glass sheet test piece 14 is placed on the support table 15;

(3) pressure was applied to the glass sheet coupon from directly above the centerline thereof by a stainless steel pressure tool 16 having dimensions of 50mm (L5). times.2.0 mm (L6). times.10 mm (L7);

(4) when the test piece is broken, measuring the maximum pressure;

(5) the maximum pressure is defined as the strength of the glass substrate.

The strength of the glass substrate of example 1 was 1500 g. On the other hand, the strength of the glass substrate of comparative example 1 was 1000 g. That is, it can be seen that the strength of the glass substrate is increased.

(example 2)

Two glass sheets for liquid crystal display each having a size of 400mm × 500mm × 0.7mm were bonded to each other with a sealing agent. Masks are made on both surfaces and one side surface of the bonded glass. A stack of thin films is applied in the mask. The laminated film applied in the mask was then stripped of a strip of 0.2mm width. The peeling portion is a slit-formed portion. Peeling off the laminated film was performed on both surfaces of the bonded glass. The peeled portion of the laminated film on the lower surface of the bonded glass is located directly below the peeled portion of the laminated film on the upper surface of the bonded glass.

Followed by chemical treatment. The chemical treatment solution and the conditions for generating bubbles in the chemical treatment solution were similar to those in example 1. The bonded glass is immersed in the chemical treatment solution such that the surface of the chemical treatment solution and the surface of the bonded glass are parallel to each other. That is, as the bonded glass descends into solution, the bubbles should impact the bonded glass in a vertical direction. The chemical treatment was carried out until a slit having a depth of 0.05mm was formed.

Thereafter, pressure is applied to cut the bonded glass. The glass substrate obtained in the above procedure was observed under a microscope. As a result, it was confirmed that no crack was generated on the end face of the glass substrate. This further confirmed that the cut surface was smooth.

The strength of the glass substrate obtained in example 2 was measured in the same manner as in example 1. The strength of the glass substrate was 1500 g.

(example 3)

The cutting method of the glass substrate is different from that in example 2 only in the peeling method of the laminated film. The peeling of the laminated film from the upper and lower surfaces of the bonded glass substrate is parallel to each other. Further, the laminated films on the upper and lower surfaces of the bonded glass substrate were peeled off such that the interval between the peeling tapes was 0.2mm when viewed from above.

The glass substrate obtained in example 3 was observed under a microscope. As a result, it was confirmed that cracks at the end face of the glass substrate and cracks on the cut face thereof were both suppressed. The cut surface is determined to be smooth. The glass substrate was observed from one side thereof under a microscope. Fig. 8 is a schematic side view of a glass substrate. It was found that the glass-cut portion was formed into a stepped shape.

Claims (12)

1. A method for cutting a glass substrate for a flat panel display comprises the following steps:

performing a mask corresponding to a cutting pattern on a glass surface of a glass substrate for a flat panel display or forming a scribe line along the cutting pattern;

forming a slit on a surface of the glass on which the mask is not applied, or deepening the scribe line, by contacting a chemical treatment solution;

then, a mechanical stress or a thermal stress is applied to the slit or the deepened scribe line to cut the glass substrate.

2. The method of cutting a glass substrate for a flat panel display according to claim 1, wherein a mask corresponding to the cutting pattern is applied on the glass surface by means of a screen printing method, a laminate film processing method or a resist coating photolithography method.

3. The method of cutting a glass substrate for flat panel displays as claimed in claim 1, wherein the chemical treatment is immersing the glass in a chemical treatment solution.

4. The method of cutting a glass substrate for flat panel displays as claimed in claim 3, wherein the chemical treatment generates bubbles or jets in the chemical treatment solution.

5. The method of cutting a glass substrate for flat panel displays as claimed in claim 4, wherein the chemical treatment is carried out by flowing a chemical treatment solution along the surface of the glass.

6. The method of cutting a glass substrate for a flat panel display according to claim 4 or 5, wherein the chemical treatment is performed by flowing a chemical treatment solution into a portion where the scribe lines or slits are formed.

7. The method of cutting a glass substrate for a flat panel display according to claim 1, wherein the chemical treatment is spraying a chemical treatment solution on the glass surface, blowing vapor of the chemical treatment solution on the glass surface, or exposing the glass surface to the vapor of the chemical treatment solution.

8. The method of cutting a glass substrate for a flat panel display according to claim 1, wherein after the chemical treatment is completed, a pulling force is applied in a direction of pulling the glass segments apart from each other centering on the scribe line or the slit.

9. The method of cutting a glass substrate for a flat panel display according to claim 1, wherein after the chemical treatment is completed, a pressure is applied in a direction facing a surface on which the scribe line or the slit is formed or in a direction facing another surface opposite to the surface on which the scribe line or the slit is formed, thereby applying a mechanical stress to the scribe line or the slit to cut the glass.

10. The method of cutting a glass substrate for a flat panel display according to claim 1, wherein after the chemical treatment, both sides of the scribe line or the slit are irradiated with a laser to cut the glass.

11. A glass substrate for flat panel displays, characterized by being produced by the cutting method according to any one of claims 1 to 10.

12. A flat panel display, characterized in that the glass substrate according to claim 11 is applied.