JPH08175837A - Method for cleaving glass plate and apparatus therefor - Google Patents

Abstract

PURPOSE: To provide a method and device for dividing a plate glass capable or reducing the generation of a glass fine powder at and after dividing and aiming to prevent the divided plane from the generation of micro-cracks by employing a specific means in dividing the plate glass along the projected dividing lines. CONSTITUTION: This method for dividing a plate glass comprises forming a pre-crack 2a becoming a starting point of a dividing line 2 with a dividing tool 3 at the end part of the plate glass 1 on a projected dividing line 2b of the plate glass 1, applying a bending moment around the projected dividing line 2b e.g. by inserting a wedge 5 at the time of or directly after the forming of the pre-crack 2a, then dividing the plate glass 1 by heating the vicinity of the end of the dividing line 2 with a heating means 4 (e.g. a carbon dioxide gas laser) to progress the dividing line 2 on the projected dividing line 2b and also applying the bending moment around the projected dividing line 2b at or just after the progress of the dividing line 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaving a glass plate, and more particularly to a method and a device for cleaving a glass plate which hardly generate fine glass powder.

[0002]

2. Description of the Related Art Conventionally, for cutting a glass sheet, a cutting wheel made of cemented carbide or the like is pressed under a constant load to make a cutting line, and then a bending force (bending moment) is applied around the cutting line. The method of cutting is taken.

At this time, in order to prevent the breaking line from breaking apart from the cutting line, it is necessary to apply a sufficiently large load to the cutting line. Therefore, in addition to the median crack that progresses in the thickness direction of the glass plate originally necessary for cutting, a lateral crack that progresses substantially parallel to the surface of the glass plate occurs in the glass surface layer portion,
Since this is peeled off when the score line is formed or after cutting, generation of fine glass powder is unavoidable.

The fine glass powder adheres to a glass mounting table or the like and causes fine scratches on the glass surface, and the fine glass powder adhered to the glass surface damages the glass surface during cleaning or cannot be removed by cleaning. There is a problem that the fine glass powder may damage the surface of the glass plate when polishing the surface of the glass plate or when stacking the glass plates.

[0005]

By the way, as a cutting method in which fine glass powder is relatively less likely to be generated, there is known a method of cutting glass by causing thermal stress by a carbon dioxide laser (report by FP Gagliano and RM Lumley ( Proc. Of the IEEE, vol. 57, no. 2, 1969)). This is also known as a method of cutting glass into an arbitrary shape (Japanese Patent Publication No. 3-13040).

However, even by these methods, when the glass plate is cut, it is necessary to form a preliminary crack which becomes the starting point of the cutting at the end portion of the glass plate. Fine powder is produced. Also, apart from that,
There is a problem that the cleaving does not reach the opposite end of the glass plate because the cleaving stops even though it is a short distance, leaving a part. At this time, if the glass plate is broken again, sufficient dimensional accuracy may not be obtained.

FIG. 2 is a perspective view of the breaking line showing such a state, and shows a breaking line 12 formed from a preliminary crack 11 formed at the end of the glass plate 1 as a starting point. Thirteen
Indicates the uncut portion.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. First, in a glass plate cutting method for cutting a glass plate along a planned cutting line, the glass plate is A pre-crack forming step of adding a bending moment around the planned cleavage line at the time of or immediately after the formation of the pre-crack while forming a pre-crack at the end of the glass plate on the planned cleavage line of By applying local heating near the end of the breaking line, the breaking line progresses on the planned breaking line to break the glass sheet, and around the breaking line during or immediately after stopping the breaking line. With a cleaving process that applies a bending moment,
A method for cleaving a glass plate is provided.

Secondly, a cutting tool for forming a preliminary crack as a starting point of the breaking line on the glass plate along the planned breaking line, a heating means for locally heating near the end of the breaking line, and the planned breaking line. Cleaving a glass sheet, comprising: a heating point moving means for moving the heating means and the glass sheet relative to each other, and a bending moment urging means for applying a bending moment around a planned breaking line of the glass sheet. Provide a device.

[0011]

In the present invention, the depth of the preliminary crack can be increased by using the bending moment together with the formation of the preliminary crack which is the starting point of the fracture. Therefore, just by running the cutting tool under an extremely weak load, a deep preliminary crack having a sufficient depth to cause thermal stress fracture can be formed, and the generation of fine glass powder at the preliminary crack portion can be suppressed.

Further, by locally applying heating to the vicinity of the end portion of the split line while applying a bending moment around the planned split line, the split line advances on the planned split line, leaving uncut portion at the end portion. Hateful.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of the basic structure of the present invention.

The glass plate 1 to be cleaved is placed on a moving table 7 via a protective sheet 6 having a function of a cushioning material in order to protect the glass plate from an impact when the glass is cleaved. In this example, the moving point is moved by the moving table 7. That is, the heating means 4 is fixed,
When the moving table moves in the planned cutting line, the glass plate and the heating means relatively move along the planned cutting line.

Further, a wedge 5 as a bending moment urging means is inserted at the end of the glass plate at a position along the planned dividing line between the glass plate 1 and the protective sheet 7. Further, the moving table 7 is capable of vacuum suction, and since the protective sheet 6 has many suction holes, the glass plate 1 is vacuum-sucked on the protective sheet 6 and cut into the glass plate 1. A bending moment along the planned line is added. Depending on the shape of the wedge, the weight of the glass plate 1 may affect the weight of the glass plate 1.
It is also possible to add a bending moment along the planned breaking line to.

In the figure, 2 is a breaking line, 3 is a cutting tool for forming a preliminary crack, 8 is a cutting tool supporting and pressing means for supporting the cutting tool and pressing it against the glass plate.

In this example, the moving table 7 was used as the heating point moving means, but any means may be used as long as it moves the heating means and the glass plate relatively along the planned cutting line.
In particular, contrary to this example, the glass plate 1 is fixed and the heating means 4 is
May be moved.

As the heating means 4, laser light, heated air, combustion flame, etc. can be used alone or in combination. Excimer laser, YA
It is desirable to use laser light or a combustion flame such as a G laser, a carbon dioxide laser or a carbon monoxide laser. In particular, for energy absorption efficiency and economic reasons, it is desirable to use a carbon dioxide laser or a combustion flame.

In the present invention, it is necessary to locally heat the vicinity of the end of the breaking line in order to advance the breaking line on the planned breaking line without displacement. For local heating, it is desirable to guide the heating source to a predetermined place. When laser light is used as the heating means 4, a crystal fiber light guide path,
Light can be guided by an optical system including a hollow thin tube light guide path and a lens / mirror, and a heat source can be guided by a heat-resistant tube or the like when heated air is used and a combustion nozzle and a rubber tube or the like when combustion flame is used.

As the cutting tool 3, a cutter having a sharp tip such as single crystal diamond or sintered diamond can be used.

The wedge used as the protective sheet 6 and the bending moment urging means 5 is preferably made of an organic polymer in order to avoid damage to the glass plate 1, and particularly, a heat-resistant PTFE sheet, a polyimide resin sheet, A fluororubber sheet or the like is preferable.

The bending moment urging means may be provided at least in the vicinity of the preliminary crack forming portion and in the vicinity of the end portion of the glass plate forming the preliminary crack in the direction opposite to the end portion (that is, in the vicinity of the end of the cleavage line). In FIG. 1, the wedge 5 is provided separately at two locations near the pre-crack formation location and near the end of the split line. On the other hand, the wedge 5a used for cutting in the direction perpendicular to the planned cutting line 2b is provided over the entire width of the glass plate.

Next, the operation of the apparatus of this example will be described. First, the glass plate 1 is placed on the moving table 7 via the protective sheet 6 and the wedge 5 at a predetermined position, and vacuum suction is performed. Then, in that state, the blade portion of the cutting tool 3 is pressed against the glass plate 1 by the cutting tool supporting and pressing means 8,
A preliminary crack 2a, which is the starting point of the breaking line 2, is formed on the planned breaking line 2b at the end of the glass plate 1. Further, the heating means 4 locally heats the vicinity of the end of the split line. In this way, stress concentration is caused on the planned breaking line by the breaking line and heat, and the breaking line 2 advances to the planned breaking line 2b. At this time, the moving table 7 moves the heating means 4 relative to the glass plate 1 along the planned cutting line.

According to the apparatus of the present invention, the formation of the preliminary crack by the cutting tool 3 can be performed with a weak load of about 20 to 200 gf. Performing pre-crack formation with such a light weight is very preferable in the sense of avoiding generation of fine powder of glass. In the above embodiment, the bending moment is applied at the same time when the preliminary crack is formed, but the bending moment may be applied after the preliminary crack is formed and before the local heating. However, in order to shorten the time required for cleaving, it is more preferable to form the cracks simultaneously with the formation of the preliminary cracks.

The method for generating the bending moment in the glass plate 1 is not limited to the method of this embodiment, and various methods can be adopted. For example, a method to generate bending stress by pressing both sides of the wedge with rolls,
A method of pressing the glass from the back surface or both surfaces of the glass with a pressure roll or the like can be used.

FIG. 3 is a side view of the arrangement of the pressure rolls when the pressure rolls are used, and 21 to 23 show the pressure rolls. It is not always necessary to provide all of these pressure rolls, and the bending moment can be added only by the pressure roll 21.

The cleaving was specifically performed as follows.
A polyimide resin sheet having fine holes for vacuum suction at predetermined positions was bonded as a protective sheet to a moving table 7 capable of vacuum suction of 1 m square. Furthermore, as a wedge, x
With a length of 1 m, a width of 1 mm, and a height of 0.2 mm
Sheets are bonded 150mm apart, 50mm apart from both sides for a total of 7 rows bonded, and in the y direction only 150mm long, 10mm long, 1mm wide, 0.2mm high PTFE sheet is 150mm.
A total of 14 pieces were bonded at intervals of 50 mm from both sides.

A glass plate having a length of 1 m, a width of 1 m, and a thickness of 0.7 mm made of soda-lime glass that had been thoroughly washed was placed on this, and vacuum suction was performed to hold it. While the diamond cutter as the cutting tool 3 was linearly moved in the horizontal direction at a speed of 50 mm per second, the cutter was moved up and down and a cutting line having a length of 5 mm was inserted near the edge of the glass with a load of about 40 g. By moving the carbon dioxide laser beam light guided by the carbon dioxide laser hollow thin tube light guide,
Cleaving was possible using the above cutting line as a starting point.

The intensity of the carbon dioxide laser beam was about 50 watts on the glass surface. A total of 150 pieces for this cutting
A glass substrate of × 150 mm was obtained. These substrates were observed in a dark room under a light source of 200,000 lux, but no fine glass powder was observed, and the dimensional accuracy of cutting was within ± 0.1 mm for the entire circumference including the starting point and the end. Met.

[0031]

According to the present invention, the following effects are achieved.

1) The generation of fine glass powder during and after cutting is extremely small, so that a glass substrate with little adhesion of fine glass powder can be obtained without special cleaning.

2) Since scratches generated in the polishing process of the glass substrate are reduced, the polishing processing time can be shortened.

3) High-speed cutting can be performed with a high yield as compared with the case where a bending moment is not used together.

4) Since no uncut portion is left, cutting with high dimensional accuracy can be performed.

5) Since the cut surface has no microcracks, the mechanical strength of the glass is high, and cleaning residues are unlikely to remain, so that a clean surface is easily obtained.

6) It is not necessary to wash the glass because no grinding oil or the like adheres to it.

According to the present invention, even thin glass having a cutting line of 0.2 mm or less, which is difficult to insert, can be cut with a good yield without damaging the glass.

7) The present invention is particularly applicable to a liquid crystal display device (LC).
It is extremely effective when used for producing a substrate for D). That is, since almost no fine glass powder is generated at the time of cutting, it is possible to prevent foreign matter from remaining on the liquid crystal display element substrate, causing an electrical short circuit and uneven color due to variation in the liquid crystal layer thickness within the substrate. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of an entire apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a breaking line.

FIG. 3 is a side view of a pressure roll unit according to another embodiment of the present invention.

[Explanation of symbols]

 1: Glass plate 2: Cutting line 3: Cutting tool 4: Heating means 5: Bending moment urging means 6: Protective sheet 7: Moving table 11: Preliminary crack 12: Cutting line 13: Uncut portion 21, 22, 23: Pressure roll

Claims (6)

[Claims] 1. A method for cleaving a glass plate along a planned breaking line, comprising forming a preliminary crack at the end of the glass plate on the planned breaking line of the glass plate as a starting point of the breaking line, and preparing a preliminary crack. A preliminary crack formation process in which a bending moment is applied around the planned cleavage line during or immediately after the formation of a crack, and then local heating is applied near the ends of the cleavage line to advance the cleavage line on the planned cleavage line. And a cleaving step of applying a bending moment around the planned cleaving line during or immediately after the cleaving of the glass sheet. 2. The method for cleaving a glass sheet according to claim 1, wherein a carbon dioxide laser or a combustion flame is used as a heating source for locally heating. 3. The method for cleaving a glass sheet according to claim 1, wherein the preliminary crack is formed by making a cutting line with a weight of 200 gf or less. 4. A cutting tool for forming a preliminary crack which is a starting point of a breaking line on a glass plate along the planned breaking line, a heating means for locally heating near the end of the breaking line, and a planned breaking line. A glass sheet cleaving device comprising: a heating point moving means for relatively moving the heating means and the glass plate along the bending point; and a bending moment urging means for applying a bending moment around the expected breaking line of the glass plate. . 5. The glass sheet cleaving device according to claim 4, wherein the bending moment urging means comprises a pressure roll. 6. The glass plate cleaving device according to claim 4, wherein the bending moment urging means comprises a wedge.