JP2001026435A - Scribing/breaking method of hard brittle plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scribing/breaking method of a hard brittle plate represented by a glass plate, which enables the scribing/breaking of such a plate with high productivity by using a heat beam such as laser beam. SOLUTION: This method comprises: allowing the sharp hp or peripheral edge of a tool 2 to contact with one surface of a hard brittle plate 1 and to move on the surface along a desired cut-off line to form a scribe line 4; irradiating the other opposite surface of the hard brittle plate 1 with a heat beam 3 for locally heating the plate, such as laser beam, at such a point that it is positioned so as to correspond to the scribe line 4 of the one surface; and moving this irradiation point on the other opposite surface along the scribe line 4 to break the hard brittle plate 1; wherein a procedure for this method, which involves forming the scribe line 4 in the lower surface of the hard brittle plate 1 horizontally supported and irradiating the upper surface of the plate 1 with such a heat beam 3, is excellent from the viewpoint of the treatment of dust caused in the breaking stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dividing a hard brittle plate typified by a glass plate along a predetermined line and dividing the plate, for example, when manufacturing a flat panel display such as a liquid crystal display or a plasma display. ,
The present invention relates to a method used for cutting a glass substrate on which a display element is formed into a predetermined size.

[0002]

2. Description of the Related Art In manufacturing a flat panel display such as a liquid crystal display or a plasma display, a plurality of display elements are formed on a large-area glass substrate and then cut into a plurality of pieces in order to increase productivity. Since a method of obtaining a display plate of a required size is adopted, a step of cutting a glass substrate along a predetermined cutting line at the time of its manufacture is indispensable. Hard brittle materials, such as glass plates,
Cutting with a diamond saw or the like is also performed, but since cutting takes a very long time, a method of cutting using cracks based on brittleness of the material is widely adopted.

[0003] The most commonly used method of cutting a glass plate or the like at the present time is to apply a sharp tip or a sharp peripheral edge of a carbide tool such as a diamond tool to a glass surface to move the plate. After forming a groove (scribe line) along the cutting line, a method of applying a mechanical impact force such as bending or pulling to the plate along the groove is a two-step process of a scribing process and a breaking process.
An apparatus for performing each step is installed adjacent to the apparatus, and performs the cutting step while transferring the work from the scribing apparatus to the breaking apparatus.

[0004] On the other hand, attempts to cut the glass plate by generating local internal thermal stress have been made for a long time. The basic principle is that a laser beam or other heating beam irradiated on the surface of the hard brittle plate is caused to travel along the cutting line, and cracks due to local thermal stress generated in the part irradiated with the heating beam are cut into the cutting line. It is to progress along. In the method of cutting a hard and brittle plate using the local heating beam, various improved methods have been proposed for the purpose of improving the cutting speed and the accuracy of the fractured surface.

For example, Japanese Patent Application Laid-Open No. 59-97545 discloses a method in which a scribing line is previously inserted into a portion of a glass plate to be broken with a carbide tip or the like, and a laser beam is irradiated on the line to break by a thermal shock. Has been proposed, and JP-A-5-32428 discloses that
By irradiating the surface of the glass body to be processed with a laser beam in the ultraviolet region having a high absorptivity to the glass body and scanning the irradiation point along a target cutting line, the surface of the glass body to be processed is scanned. A glass processing method has been proposed that includes a step of performing scribing and a step of irradiating a laser beam in an infrared region along the scribed portion to apply thermal strain to the portion, which is associated with cleavage.

[0006]

A method of cutting a hard brittle plate using a laser beam has not been put to practical use, although various methods have been proposed for a long time, but its main reason is its low processing efficiency. For this reason, a breaking method using a mechanical impact force, which has a relatively high possibility that a crack is deviated from a desired cutting line and that requires a large installation space for the machine, is used.

However, a flat panel display is
Very fine light-emitting or light-blocking elements are arranged on the surface of the glass substrate, and are manufactured in a clean room because they extremely dislike dust.However, in mechanical scribing and breaking, they are fine and sometimes quite large. Glass fragments are generated, and in severe cases, the cut portions are chipped, which lowers the quality of the product or lowers the yield of the product. In addition, when mechanical breaking is performed, it is necessary to form a deep scribe groove so that cracks do not deviate from the cutting line or chipping does not occur in the cut portion, which lowers productivity and occurs. There is a problem in that dust is increased and the scribing cutters (points and rollers) are worn faster, and the machine must be frequently stopped for replacement.

Further, since two devices, a scribing device and a breaking device, are required for the cutting, an economical disadvantage that the installation area of the machine becomes large and the floor area of the clean room must be large. There is also.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of a method of cutting a hard brittle plate by mechanical scribing and breaking, which is generally performed at present, so that a hard material having a high productivity by a laser beam or other heating beam is used. It is an object to obtain a method for cleaving a brittle plate.

[0010]

According to the method of the present invention, a sharp tip or a peripheral edge of a tool having a higher hardness than the hard brittle plate is moved in contact with one surface of the hard brittle plate along a desired cutting line. By forming a scribe line, irradiating a laser beam or another heating beam for locally heating the hard brittle plate to the surface opposite to the surface on which the scribe line is formed, and moving the irradiation point along the scribe line. , Breaking the hard brittle plate.

In this case, the hard brittle plate to be cleaved is horizontally supported, a scribe line is formed on the lower surface of the hard brittle plate, and a heating beam is irradiated on the upper surface of the hard brittle plate during the cutting. Excellent in handling dust.

When the method of the present invention is applied to a cutting device for a hard brittle plate, a tool for forming a scribe line and a heating beam irradiation device are opposed to each other with a hard brittle plate to be cut therebetween. The irradiation point is arranged at a predetermined distance behind the tool in the traveling direction, and the tool and the irradiation point of the heating beam are moved along the cutting line of the hard brittle plate while maintaining the predetermined distance or the distance range. The method is advantageous in terms of working efficiency and equipment space.

The cutting line is not limited to a straight line, but can be cut along a circle or a free curve. The heating beam can be made to travel while being reciprocated back and forth along the cutting line, and it is usually preferable to add such reciprocation.

[0014]

According to the method of the present invention, the formation of a scribe line and the irradiation of a heating beam are performed on the same surface of a hard brittle plate to be cut.
In contrast to the conventional method described in the publication, the difference is that the formation of the scribe line and the irradiation of the heating beam are performed on the mutually opposite surfaces of the hard brittle plate. The following large differences occur in terms of the amount of dust generated at the time of cutting and wear of the carbide tool.

When the heating beam is irradiated on one surface of the hard and brittle plate, a local heating region is generated at a position of the condensing point in the thickness direction of the plate which is biased to the side where the heating beam is irradiated.
In the conventional method, as shown in FIG. 3, since the heating beam 3 is irradiated toward the surface on which the scribe line 4 is formed, the local heating region 5 is formed in the thickness direction of the hard brittle plate 1 by the scribe line. The heating area is generated in a portion biased toward the side where the scribe line 4 is provided, and the heating area includes the scribe line 4. This is because the scribe line is irradiated with the heating beam having the maximum energy that has not been attenuated.

The vitreous material of the heating zone 5 expands due to heat and tends to push out the surrounding unheated glass. Naturally, as this reaction, a compressive stress acts on the glass in the heated area. That is, in the conventional method, since the thermal stress acting on the groove bottom of the scribe line in the heating area is a compressive stress, it does not effectively act on the cutting of the glass sheet.

In practice, the heating area 5 extends in the plane of the hard brittle plate 1 as shown in FIG. 5, and a circumferential tensile stress is generated around the area. Therefore, even in the conventional method, the wafer is cut by the tensile stress in the circumferential direction. However, since the sheet is on the compression side in the thickness direction, the cutting efficiency does not increase and a deep scribe line must be provided.

On the other hand, in the method of the present invention shown in FIG. 2, the surface on which the scribe line 4 is formed and the surface on which the heating beam 3 is irradiated are opposite surfaces. The position is deviated to the opposite side of the scribe line 4 in the thickness direction of the hard brittle plate 1. The vitreous material of the heating area 5 tends to expand by expanding the surrounding unheated glass. This power to push is
A tangential tensile force is generated in an unheated portion around the heating area 5. When the heating region 5 is widened, the groove bottom portion of the scribe line 4 also becomes a compression region as shown in FIG. 4, but a circumferential tensile stress is generated around the planar heating region in FIG. The tensile stress in the state shown in FIG. 2 is generated at the outer peripheral portion. Since these tensile forces become stresses in the direction in which the hard brittle plate 1 is locally separated to both sides around the scribe line 4, local cracks generated at the groove bottom of the scribe line 4 progress linearly in the plate thickness direction. In addition, a cut surface with good squareness and surface accuracy can be obtained.

If the planar heating region is an elliptical region that is long in the cutting direction as shown in FIG. 6, the circumferential tensile stress at the forward end of the heating region 5 in which cutting starts can be increased. Cutting efficiency can be further improved. The elliptical heating area can be realized by traveling while reciprocating the irradiation point of the heating beam in the direction along the cutting line as shown by the arrow D in FIG. The point A in FIGS. 5 and 6 is the contact position of the tool forming the scribe line 4, and this position is outside the heating area 5.

As can be understood from the above description, according to the invention of this application, the stress concentration due to the provision of the scribe line and the local thermal stress due to the irradiation of the heating beam are optimal for cutting the hard brittle plate. Therefore, the cutting speed is high, and the accuracy of the split section can be increased. Also, the groove depth of the scribe line may be shallow (because of local stress concentration, depending on the shape of the deep end of the groove of the scribe line, the magnitude of the local stress does not change even if the groove depth is reduced) ), The scribe line can be formed at a high speed, and the wear amount of the tool is small.

Further, since the groove depth of the scribe line may be small, dust generated by forming the scribe line is greatly reduced. Also, if the hard brittle plate to be cut is supported on a horizontal surface and a scribe line is formed on the lower surface, dust generated when forming the scribe line falls down or is sucked from below. Will be eliminated promptly. During the breaking by the heating beam, almost no dust is generated.

According to the third aspect of the present invention, scribing and breaking can be performed in one step on the same machine. In a flat panel display manufacturing facility, the installation area of the machine required for the glass substrate cleaving step is reduced. It can be halved and the floor area of the clean room is small.

[0023]

FIG. 1 is a perspective view schematically showing the method of the present invention. This embodiment shows a method of cutting a glass plate 1 as a hard brittle plate along a straight cutting line. The glass plate 1 to be cut is supported by a horizontal table having a groove, and a scribing roller 2 is arranged in the groove of the table. The scribing roller 2 is pressed upward and pressed against the lower surface of the glass plate 1.

Laser light projected from a carbon dioxide laser oscillator or the like is focused on the upper surface of the glass plate 1 through an appropriate optical system including a focusing lens. The contact point A of the scribing roller 2 and the focal point B of the laser beam 3 are separated by a predetermined distance in the tangential direction of the outer peripheral edge of the scribing roller 2.

In this state, the scribing roller 2 and the laser beam 3 are driven synchronously in the direction indicated by the arrow C in the figure, that is, in the tangential direction of the scribing roller 2, so that the roller runs ahead of the laser beam, or By moving the table supporting the glass plate 1 in the direction opposite to the arrow C in the figure while keeping the position of the laser beam 2 and the position of the focal point B of the laser beam fixed, the lower surface of the glass plate 1 The scribe line 4 is formed by the scribing roller 2, and the laser beam converging point B is scanned on the upper surface of the glass plate facing the scribe line with a predetermined distance from the contact position of the scribing roller 2. The glass plate 1 is cut at the focal point B of the laser beam by local cracks growing from the bottom of the scribe line 4.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the method of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a scribe line and a region heated by a laser beam in the method of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a scribe line and a laser light heating region according to a conventional method.

FIG. 4 is an explanatory diagram showing a relationship between a scribe line and a heating region by a laser beam in the method of the present invention when the heating region is expanded.

FIG. 5 is an explanatory diagram showing a planar spread of a heating region and a stress around it.

FIG. 6 is an explanatory diagram showing an example in which the planar extent of a heating region is made elliptical.

[Explanation of symbols]

 Reference Signs List 1 glass plate 2 scribing roller 3 laser beam 4 scribe line

 ──────────────────────────────────────────────────の Continuing on the front page (72) Noriaki Yoshida, Inventor, No. 15, Atano-cho, Tsurugi-cho, Ishikawa-gun, Ishikawa Pref. CE04 DA14 DB00 DB13 4G015 FA03 FA06 FB02 FC02 FC14

Claims (3)

[Claims] 1. A scribe line is formed on one surface of a hard brittle plate by contacting and moving a sharp tip or a peripheral edge of a tool having a higher hardness than the hard brittle plate along a desired cutting line. A method for cutting a hard brittle plate, comprising irradiating a heating beam for locally heating the hard brittle plate to a surface opposite to the surface on which the surface is formed, and moving the irradiation point along the scribe line. 2. A hard brittle plate to be cleaved is supported on a horizontal surface, and a scribe line is formed on a lower surface of the hard brittle plate.
The method for cutting a hard brittle plate according to claim 1, wherein a heating beam is applied to an upper surface of the hard brittle plate. 3. A tool for forming a scribe line and a heating beam irradiation device are opposed to each other with a hard brittle plate to be cut interposed therebetween, and a heating beam irradiation point is located at a predetermined distance behind a running direction of the tool. The hard brittle material according to claim 1 or 2, wherein the tool and the irradiation point of the heating beam are set and run along a cutting line of the hard brittle plate while maintaining the predetermined distance or the distance range. How to cut the board.