Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-03-30
2001-04-24
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S109000
Reexamination Certificate
active
06221190
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for processing a glass panel.
A conventional process for fabricating a glass panel such as a vacuum heat-insulating glass panel or a plasma display panel (hereinafter abbreviated to PDP) comprises the step of sealing a glass panel assembly constructed from two glass plates, one with an exhaust pipe thereto, which are joined together by a jig such as a clip with a sealant applied to the periphery of one or the other of the opposing surfaces of the two glass plates, the step of evacuating the interior of the sealed glass panel through the exhaust pipe and the step of cutting and sealing up the exhaust pipe.
In the sealing step, the glass panel assembly is loaded into a batch-type sealing furnace and heated to a predetermined temperature (sealing temperature) to seal the two glass plates which are thus fabricated into a glass panel. In the evacuating step, many such glass panels, each with the exhaust pipe attached thereto, are loaded into a batch-type evacuating furnace and, while heating the glass panels at a predetermined temperature (evacuating temperature), an evacuating apparatus connected to the exhaust pipe is driven to evacuate the interior of the glass plate, and finally the exhaust pipe is sealed up and cut to complete the fabrication of the glass panel.
In particular, in the fabrication process of the PDP, the evacuating step is followed by the step of filling a discharge gas into the glass panel to a predetermined pressure (400 to 600 Torr), after which the exhaust pipe is sealed up and cut.
However, since the sealing step and the evacuating step are batch processes separately performed in special-purpose furnaces, raising and lowering the furnace temperature is repeated for each process, the resulting problem being that not only thermal efficiency is low but productivity also decreases enormously.
SUMMARY OF THE INVENTION
The present invention has been developed to substantially eliminate the above-described disadvantages.
It is therefore an object of the present invention to provide a method and apparatus for processing a glass panel in which not only thermal efficiency can be enhanced but productivity can also be improved.
According to the invention, there is provided a method for processing a glass panel, comprising the steps of:
supporting at least one glass panel assembly on an evacuating cart in such a manner as to be positioned inside a furnace, the glass panel assembly being constructed from two glass plates, any one of the glass panels being provided with an exhaust pipe, the glass plates being joined together by a jig with a sealant applied along a periphery of one or the other of the opposing surfaces of the two glass plates, the exhaust pipe being connected to an evacuating system;
sealing the two glass plates to form a glass panel by heating the glass panel assembly and melting the sealant while moving the evacuating cart through the furnace;
evacuating air and dirty gas between the two glass plates of the glass panel by the evacuating system until the predetermined degree of vacuum is achieved; and
sealing and cutting the exhaust pipe.
In the above invention, the glass panel assembly with the exhaust pipe attached thereto is loaded onto the evacuating cart mounted with the evacuating system, and is passed through the sealing/evacuating furnace where the glass plates are sealed together with a sealant and then the interior is evacuated by a vacuum. After this evacuating step, the exhaust pipe is fused and sealed up. That is, the glass panel sealing and evacuation and exhaust pipe sealing steps are performed continuously as the evacuating cart moves. In this way, according to the present invention, since the sealing of the glass plates and the evacuation of the panel interior are not performed by batch processes as was the case with the prior art, not only thermal efficiency can be enhanced but productivity can also be improved.
Preferably, the exhaust pipe is connected switchably between the evacuating system and a discharge gas supply system, and wherein the method further comprises the step of filling a discharge gas into the glass panel after the step of evacuating and before the step of sealing and cutting.
In this case, the evacuating cart is mounted with a discharge gas supply system, and the step of filling a discharge gas is performed after the evacuating step but before the exhaust pipe sealing step. This contributes to increasing thermal efficiency and improving productivity of the PDP.
The present invention is also directed to an apparatus for processing a glass panel, comprising:
a plurality of evacuating carts for supporting at least one glass panel assembly, the glass panel assembly being constructed from two glass plates, any one of the glass panels being provided with an exhaust pipe, the glass plates being joined together by a jig with a sealant applied along a periphery of one or the other of the opposing surfaces of the two glass plates, each evacuating cart being provided with an evacuating system connected to the exhaust pipe and a sealing heater for fusing and cutting the exhaust pipe; and
a furnace for heating the glass panel assembly on the plurality of evacuating carts which are moved on rails and charged into the furnace in a connected condition one behind another;
whereby the glass panel assembly is heated so that the sealant melted to seal the two glass plates and form a glass panel;
air between the two glass plates of the glass panel is evacuated by the evacuating system until the predetermined degree of vacuum is achieved; and
the exhaust pipe is sealed and cut.
Preferably, the furnace has an opening in the furnace bed extending along the moving direction of the evacuating cart,
the evacuating cart moves on the rails laid beneath the furnace bed, and
the evacuating cart is provided with a plurality of mounting members each comprising a supporting pillar extending into the furnace through the opening in the furnace and a holding member for holding the glass panel assembly in the furnace. In this case, the supporting pillar of the mounting members are preferably provided with an insulating member for closing the opening of the furnace.
Preferably, the furnace comprises a sealing zone, an evacuating zone and a cooling zone, and wherein in the sealing zone the two glass plates are sealed to form the glass panel, in the evacuating zone air and dirty gas in the glass panel are evacuated, and in the cooling zone the glass panel is cooled.
Preferably, the exhaust pipe is connected switchably between the evacuating system and a discharge gas supply system, and wherein a discharge gas is filled into the glass panel from the discharge gas supply system after evacuating the glass panel and before sealing and cutting the exhaust pipe.
Preferably, the appratus further comprises a discharge gas filling/sealing zone, whereby in the discharge gas filling/sealing zone a discharge gas is filled into the glass panel from the discharge gas supply system after evacuating the glass panel and before sealing and cutting the exhaust pipe.
Preferably, the apparatus further comprises;
a second rails laid on one side of the furnace on which the evacuating carts move in a direction opposite to the moving direction of the evacuating carts on the first rails;
a charge side transfer car for transferring the evacuating cart to the upstream end of the first rails from the downstream end of the second rails; and
a discharge side transfer car for transferring the evacuating cart to the upstream end of the second rails form the downstream end of the first rails;
wherein the evacuating carts are circulated for use.
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patent: 3347723 (1967-10-01), Hill
patent: 3683974 (1972-08-01), Stewart et al.
patent: 3917503 (1975-11-01), Tamura et al.
patent: 4066427 (1978-01-01), Goto
patent: 4601772 (1986-07-01), McKelvey
patent: 4786344 (1988-11-01), Beuther
patent: 4963206 (1990-10-01), Shacklette et al.
patent: 61-163534A (1986-07-01), None
patent: 63-45728 (1988-11-01), Non
Seki Tadashi
Shimosato Yoshikazu
Ball Michael W.
Birch & Stewart Kolasch & Birch, LLP
Chugai Ro Co. Ltd.
Musser Barbara J.
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