JPH0920527A - Jig for heat-treating thin sheet glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a jig for heat treatment capable of ensuring a high flatness degree without causing the warpage and readily and rapidly separating a thin sheet glass in close contact with the top surface thereon. SOLUTION: This platy jig 11 for heat treatment comprises a crystallized glass having <=15×10<-7> C deg. thermal expansion coefficient and has through-holes 13 or recessed grooves which are vent holes for communicating with the contact surface with the thin sheet glass 12 and introducing air thereinto in the jig 11 for heat treatment in a state thereof having the thin sheet glass 12 horizontally placed thereon and introduced into a heat-treating furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for heat treatment of thin glass, and more specifically, when heat treating thin glass used for a liquid crystal display panel or the like, it is heat-treated in a state where the thin glass is placed horizontally. The present invention relates to a plate-shaped heat treatment jig that is introduced into a furnace.

[0002]

2. Description of the Related Art For example, a thin glass plate having a thickness of about 1 mm is used for a liquid crystal display panel or the like. In the production of this kind of thin glass, after glass forming, the thin glass 2 is horizontally placed on a heat treatment jig 1 called a setter as shown in FIG. Are doing. As the heat treatment jig 1, conventionally, a jig made of alumina ceramics is generally used. The above-mentioned heat treatment is performed as follows.

That is, the thin glass sheet after forming is placed horizontally on a heat treatment jig and introduced into a heat treatment furnace. In this heat treatment furnace, the thin glass placed on the heat treatment jig is heated and heated to a predetermined treatment temperature equal to or higher than the strain point of the glass, held for a certain period of time and gradually cooled, and then removed from the heat treatment furnace. Is discharged. This heat treatment removes the strain from the thin glass sheet.

Then, the thin glass sheet on the heat treatment jig discharged from the heat treatment furnace is separated from the heat treatment jig.
The separation of the thin glass from the heat treatment jig is generally performed by a take-out device equipped with a suction pad for vacuum-sucking the thin glass.

[0005]

By the way, the above-mentioned conventional heat treatment jig has a thermal expansion coefficient of about 71 × 10 ⁻⁷ / ° C.
Since it is made of alumina ceramics, the expansion and contraction are large, and as a result, warpage occurs and flatness is impaired.
Also, since this jig is a sintered body made of alumina ceramic fine powder, it has a large number of pores (voids) inside, and when the jig for heat treatment is heated by heat treatment, it is present in the pores. The existing impurities are emitted as gas and contaminate the thin glass sheet.

Further, after the heat treatment, the thin glass plate is in a state of being in intimate contact with the heat treatment jig, so that it is difficult to separate the glass plate quickly. It may be damaged and damaged.

The present invention has been proposed in view of the above problems, and an object thereof is to provide a thin plate which is capable of ensuring a long flatness without warpage and being in close contact with a heat treatment jig. It is an object of the present invention to provide a jig for heat treatment of thin glass, which enables easy and quick glass separation.

[0008]

As a technical means for achieving the above object, the present invention provides a plate-shaped heat treatment jig which is introduced into a heat treatment furnace in a state where thin glass sheets are horizontally mounted. It is characterized in that it is made of crystallized glass having a coefficient of thermal expansion of 15 × 10 ⁻⁷ / ° C. or less, and that it is provided with an air vent communicating with the contact surface with the thin glass plate.

[0009]

The heat treatment jig of the present invention has a thermal expansion coefficient of 15
Since it is made of low-expansion crystallized glass of ^{x10 -7} / ° C or less, there is little thermal expansion and contraction at the operating temperature of the heat treatment furnace, so that warpage does not occur and flatness can be secured for a long period of time. In addition, since it is a crystallized glass and does not have many pores (voids) inside unlike the alumina ceramics sintered body, no impurity gas is generated when the temperature of the heat treatment is raised. Do not pollute. Furthermore, since it has a ventilation hole that communicates with the contact surface with the thin glass, after heat treatment,
When separating the thin glass sheet that is in close contact with the heat treatment jig, the air can quickly enter through the ventilation holes to easily separate the thin glass sheet from the heat treatment jig.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

The heat treatment jig 11 according to the present invention has SiO ₂ , Al ₂ O ₃ , Li ₂ O, P ₂ O ₅ , and
It is made of crystallized glass obtained by heating and crystallizing a plate glass containing TiO ₂ , ZrO ₂ , and an alkali metal oxide, and has a thermal expansion coefficient of 15
× 10 ⁻⁷ / ° C. or less. Since this crystallized glass has a low coefficient of thermal expansion, it can maintain high flatness even when it is exposed to a high temperature state by a heat treatment described later. The crystallized glass (Neoceram N-0, N-11 manufactured by Nippon Electric Glass Co., Ltd.) is excellent not only in thermal characteristics such as a low coefficient of thermal expansion but also in mechanical characteristics and chemical characteristics.

The heat treatment jig 11 has a rectangular shape slightly larger than the thin glass plate 12 placed thereon, and is, for example, a plate-like body having a thickness of about 3 mm. In the example, in each of the four corners, minute through holes 13 are formed which are ventilation holes for introducing air through the contact surface with the thin glass plate 12. Two through holes 13 are formed side by side on a diagonal line at each corner, and further, one through hole 13 is formed at the center of the intersection of the two diagonal lines.

The heat treatment of the thin sheet glass using the above heat treatment jig is performed as follows.

First, the thin glass sheet is placed on the upper surface of the heat treatment jig and introduced into the heat treatment furnace. At this time, the thin glass plate is in a state in which the upper openings of the through holes at the four corners and the central part thereof are closed on the heat treatment jig. The heat treatment jig on which the thin glass is placed is transferred in the heat treatment furnace by a conveyor (not shown) made of a heat-resistant steel net, and the thin glass is placed in the vicinity of the annealing point above the strain point of the glass in the heat treatment furnace. It is heated up to a predetermined processing temperature. In this way, the thin glass sheet on the heat treatment jig is held at the above temperature for a certain period of time to remove the strain, and then discharged from the heat treatment furnace. During this heat treatment, the jig for heat treatment of the present invention maintains high flatness without warpage, and moreover, since many pores (voids) do not exist inside the jig for heat treatment, impurity gas is generated. Nor.

Thereafter, the thin glass sheet that is in close contact with the heat treatment jig discharged from the heat treatment furnace is separated from the heat treatment jig.

That is, as shown in FIG. 2 (a), the suction pads 14a to 14d of the take-out device are pressed against the four corners of the thin glass plate 12 on the heat treatment jig 11 for vacuum suction, and the thin glass plate 12 is lifted. , And separated from the heat treatment jig 11. At this time, as shown in FIG. 2B, a through hole 13 having a lower opening is present immediately below the portion of the thin glass plate 12 where the suction pad 14a is located.
From this, air flows between the thin glass plate 12 and the heat treatment jig 11, and as a result, the thin glass plate 12 adsorbed by the suction pad 14a can be easily separated from the heat treatment jig 11. Similarly for other three corners not shown,
The thin glass sheet 12 can be easily separated from the heat treatment jig 11 by vacuum suction with the suction pads 14b, 14c, 14d.

In the case of the above embodiment, two through holes 13 are arranged at four corners along a diagonal line, but the position, number and shape of the through holes 13 are not limited to those in the above embodiment. It can be set appropriately. Further, the ventilation hole is not limited to the through hole, and may be the concave groove 15 as shown in FIGS. In the present invention, the ventilation hole is not limited to the through hole and the concave groove, and any ventilation hole may be provided as long as it is provided on the surface of the heat treatment jig that contacts the thin glass sheet.

[0018]

Since the jig for heat treatment of the present invention is made of crystallized glass having a coefficient of thermal expansion of 15 × 10 ⁻⁷ / ° C. or less, thermal expansion and shrinkage are small, and therefore, when it is used for heat treatment. There is no warp and a high flatness can be secured, and since there are no pores inside, no impurity gas is generated and the thin glass sheet is not contaminated. Further, since it has a vent hole communicating with the contact surface with the thin glass sheet, the thin glass sheet can be easily and quickly separated from the heat treatment jig.

[Brief description of drawings]

FIG. 1A is a plan view showing an embodiment of a heat treatment jig of the present invention, and FIG. 1B is an enlarged cross-sectional view of a main part of FIG.

FIG. 2A is a perspective view showing a state where thin glass on a heat treatment jig of the present invention is separated by a suction pad, and FIG.

3 (a) is a plan view showing another embodiment of the heat treatment jig according to the present invention, and FIG. 3 (b) is an enlarged cross-sectional view of a main part of FIG. 3 (a).

FIG. 4 is a perspective view showing a state in which a thin glass plate is placed on a conventional heat treatment jig.

[Explanation of symbols]

 11 Jig for heat treatment 12 Thin glass 13 Vent (through hole) 14a-14d Adsorption pad 15 Vent (recessed groove)

Claims (1)

[Claims] 1. A plate-shaped heat treatment jig, which is introduced into a heat treatment furnace in a state where a thin glass plate is horizontally mounted, is made of crystallized glass having a thermal expansion coefficient of 15 × 10 ⁻⁷ / ° C. or less, A jig for heat treatment of thin glass, characterized in that a ventilation hole is provided which communicates with a contact surface with the thin glass.