JPH09255351A - Method and device for boring glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for boring a glass plate capable of easily boring the glass plate with a fine hole of a straight shape. SOLUTION: This method for boring the glass plate comprises impressing a high voltage on a pair of bar-shaped electrodes 3, 4 disposed in the opposite position of both surfaces of the glass plate 1 to generate an electric discharge, thereby causing the dielectric breakdown of the glass plate. The glass plate part to be bored with the hole is irradiated with a laser beam before or during the impression of the voltage, by which the irradiated glass part is heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making holes in glass, and more particularly to a method and apparatus for making fine through holes in the thickness direction of a glass plate.

[0002]

2. Description of the Related Art A method using an excimer laser is known as a method for making fine holes in a glass plate. This excimer laser utilizes the fact that light having a wavelength in the ultraviolet region destroys a substance non-thermally, and it is possible to perform hole processing with a size of several tens of μm. As a method of inexpensively making fine holes of a level of 100 μm, there are sandblasting in which an abrasive is jetted together with a high-speed air current, electrolytic discharge machining in which an electrical discharge is performed in an alkaline solution, and the like.

There is also a method of causing dielectric breakdown of glass by high-voltage discharge and enabling fine holes of several tens of μm level. As shown in FIG. 3, in this high-voltage discharge, high-voltage electrodes 22.23 are arranged in the vicinity of both surfaces of the glass plate 21, and a high voltage generated from the high-voltage generator 24 causes thermal insulation breakdown. The method is to evaporate the glass by the generated Joule heat.

[0004]

The processing method using the excimer laser is currently the only processing method that can practically make holes of the order of several tens of microns, but the excimer laser itself is expensive and the laser gas It also has the drawback of high running costs such as replacement. The sandblast processing method and the electrolytic discharge processing method have an advantage of low cost, but have a drawback that the hole shape is tapered. Compared to these methods, the hole forming method using high voltage discharge has the advantages of low cost and a hole shape close to a straight line, and is particularly effective for making a large number of through holes in one glass plate. However, it depends greatly on the electrical conductivity of the glass and can be applied to alkali-containing glass such as soda lime glass with high electrical conductivity, but it is very high discharge voltage for alkali-free glass with low electrical conductivity. However, there is a drawback that it cannot be applied practically because the hole position is required and the hole position cannot be accurately determined. For this reason, there is no low-cost and straight-shaped hole processing method applicable to a non-alkali glass plate used for a TFT.

It is an object of the present invention to provide a glass plate punching method and apparatus capable of easily punching straight fine holes even in a non-alkali glass plate.

[0006]

That is, the present invention is directed to a glass plate in which a high voltage is applied to a pair of rod-shaped electrodes provided at opposite positions on both sides of the glass plate to cause discharge to cause dielectric breakdown of the glass plate. In the perforating method, the glass plate portion to be perforated is irradiated with a laser to heat the irradiated glass portion before or during the application of the voltage, and the perforated glass portion is heated.

In the present invention, a pair of discharge electrodes are provided at opposite positions on both sides of the glass plate. It is preferable that the tip of the electrode be as close as possible to the surface of the glass plate because the position of the hole will be accurate, but when discharging at the same time as laser irradiation, the tip of the electrode should be made glass so that the laser irradiation light does not hit the electrode. It is positioned 0.3 to 1.0 mm from the plate surface. Since the holes are formed diagonally when the positions of the pair of electrodes arranged to face each other are shifted, it is preferable to match the positions of the electrodes as much as possible.

As the rod-shaped electrode, a conductive material having heat resistance is preferable, and concrete examples thereof include steel and carbon. Among them, steel, particularly stainless steel, is particularly preferably used. The size of the rod-shaped electrode depends on the size of the hole to be formed, but when forming a hole having a diameter of 20 μm to 1.0 mm, an electrode having a diameter of 10 μm to 2 mm is used, for example. When making a small hole with an electrode of relatively large diameter, the tip of the electrode may have a tip diameter, for example, of 10 to 10.
It is preferable to make it sharp so as to have a thickness of 50 μm.

Direct current or alternating current can be used as the voltage of the power source applied to both electrodes, but direct current is preferable from the viewpoint of easily generating a high voltage, and a current of 3 mA to 50 mA flows at a voltage of 5000 to 30000V. It is preferable to use a power source capable of controlling.

A CO ₂ laser or a YAG laser is desirable as a laser which is a means for irradiating a laser beam used in the present invention. Lasers in the visible and ultraviolet regions are not very efficient at heating glass and are not preferred. CO ₂ laser is cheaper and can heat or melt glass, but it has a wavelength of 10.6μ.
In practice, the beam spot diameter cannot be narrowed down to 100 μm or less. Therefore, the CO ₂ laser is 10
It is suitable for forming a hole having a diameter of 0 μm or more, and a light output of 5 to 25 W is preferably used. On the other hand, since the YAG laser has a wavelength of 1/10 of that of the CO ₂ laser, the spot diameter can be narrowed down to a level of several tens of μm, which allows finer holes to be formed. On the other hand, since the output light of the YAG laser is not absorbed so much by the glass, a continuous oscillation type laser with a high output of 25 to 100 W is required.

In the present invention, a glass plate portion to be locally perforated is locally heated or melted by using a heating laser, and a high voltage is applied to the glass portion whose electric conductivity is increased by the heating or melting. Is applied to cause a thermal insulation breakdown to cause discharge, and the Joule heat generated by electron avalanche causes the molten glass portion to evaporate and be removed.
As a result, it is possible to form a through hole having a diameter of 20 to 1000 μm in the glass plate.

In the present invention, the glass plate to be processed has a thickness of 0.10 to 1.5 mm, particularly 0.15 to 0.7 m.
An alkali-free glass plate having a thickness of m and an alkali-containing glass plate are preferably used.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail with reference to Examples.

As shown in FIG. 1, a non-alkali glass plate having a thickness of 0.3 mm (manufactured by NH Techno Co., Ltd., NA35)
1 is placed on an XY moving table 2 which is a table for supporting it. Rod-shaped electrodes 3 and 4 are arranged on both sides of the glass plate 1 so that their tips are located. A high DC voltage of about 10,000 V is applied to both electrodes 3 and 4 by using a high voltage generator 5 which is a means for supplying a high voltage. The electrodes 3 and 4 have a diameter of 1 mm and a length of about 10c.
The tip diameter is about 50 μm by sharpening the tip with a stainless steel (SUS304) wire of m.

On one side of the glass plate 1, as shown in FIG. 2, a CO ₂ laser 6 irradiates the irradiation light 7 with a hole in the glass plate in the middle of the tips 8 and 9 of the rod-shaped electrodes 3 and 4. It is arranged so as to face the portion 10. Electrode tips 8, 9
The irradiation light 7 is arranged so as to obliquely irradiate only the glass so that the light does not hit the irradiation light 7 and melt. First, the XY moving table 4 is adjusted so that the portion 10 of the glass plate 1 placed on the XY moving table 4 to be perforated is located between the tips 8 and 9 of the rod-shaped electrodes 3 and 4. . The tips 8 and 9 of the electrodes 3 and 4 were located at a distance of about 0.5 mm from the glass plate surfaces 11 and 12, respectively.

Then, a high DC voltage is applied to both electrodes 3, 4. At this time, since the dielectric breakdown voltage of the alkali-free glass plate is high, no current flows, and the glass plate 1 is not broken down. In a state where a voltage is applied to both electrodes, then CO ₂
When the laser 6 is irradiated for 0.5 seconds, the vicinity of the surface of the irradiated glass portion 10 is locally melted, and an electric discharge is instantaneously generated between the electrodes 3 and 4, causing a dielectric breakdown of the glass between the electrodes. The glass portion 10 is evaporated and removed by the Joule heat generated as a result, and fine holes 13 are formed. The voltage application is terminated at the same time when the irradiation of the CO ₂ laser 2 is terminated. Since the glass plate 1 is locally at a high temperature, in order to prevent the occurrence of cracks around the holes due to spontaneous cooling, the glass plate 1 was placed in an annealing furnace immediately after the holes were formed and gradually cooled.

Beam spot diameter of CO ₂ laser 600
μm, laser power 10 W, straight through hole 13 with a diameter of 700 μm in glass plate 1 by irradiation for 0.5 seconds.
Was formed. Also, the laser spot diameter is half that of 3
When it was set to 00 μm, a straight through hole having a diameter of 400 μm was formed.

In order to reduce the pore diameter, the above CO ₂
YAG with beam spot diameter of 50 μm instead of laser
When a laser was used, through holes with a diameter of 60 μm were formed. However, since the absorption of the output light of the YAG laser into the glass is very small, a laser output of 100 W was used. The heating time and the like are the same as above. The hole shape was close to straight and did not become an extreme taper shape.

In the above embodiment, the laser irradiation is performed after the application of the discharge voltage is started, but it may be applied to the discharge voltage at the same time as or after the start of the laser irradiation. Further, in the above examples, the discharge electrode and the laser were used without moving their positions, but first, the laser was irradiated perpendicularly to the glass plate surface for a predetermined time without being disturbed by the discharge electrode, and immediately after the irradiation was completed. Within (for example, within about 2 seconds), the discharge electrode, which was located at another position, may be moved to a predetermined position for discharging. The laser may be arranged not only on one side of the glass plate but also on both sides of the glass plate. In particular, when the glass plate easily absorbs the laser light and the temperature of the glass part on the laser light irradiation side is lower than the temperature of the glass part on the opposite side, it is effective to dispose the laser on both sides of the glass plate.

[0020]

According to the present invention, it is possible to easily form fine through-holes having a straight shape instead of a taper shape even with an alkali-free glass plate having a low electric conductivity, which has conventionally been difficult to make fine holes by electric discharge machining. It will be possible.

[Brief description of drawings]

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

FIG. 2 is a side view showing an enlarged main part of FIG.

FIG. 3 is a perspective view showing a drilling method using a conventional method.

[Explanation of symbols]

1: Glass plate 2: XY moving table 3, 4: Bar-shaped electrode 6: CO ₂ laser

Claims (2)

[Claims] 1. A method of punching a glass plate, wherein a high voltage is applied to a pair of rod-shaped electrodes provided at opposite positions on both sides of a glass plate to cause a dielectric breakdown of the glass plate, and before the application of the voltage. Alternatively, a method for punching a glass plate, characterized in that, during application, the glass plate portion to be punched is irradiated with laser light to heat the irradiated glass portion. 2. A support for supporting the glass plate, means for irradiating a laser beam for locally heating the glass plate, a pair of discharge rod electrodes, and means for supplying a high voltage to the rod electrodes. Glass plate punching device.