Glass manufacturing – Processes – Fusion bonding of glass to a formed part
Patent
1989-10-17
1991-03-12
Woodard, Joye L.
Glass manufacturing
Processes
Fusion bonding of glass to a formed part
65106, 65152, 65273, 65275, C03B 2302, C03B 23037
Patent
active
049990390
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to method and apparatus for manufacture of thin sheet glass by redrawing material sheet glass (glass sheet reforming method).
Thin sheet glass with a thickness of 1 mm or less to be used in liquid crystal display glass, cover glass of a solar battery, cover glass of CCD, cover glass of LED, and others may be warped, bent or creased and poor in surface precision if manufactured by ordinary sheet glass manufacturing methods such as the full course method and the slit-down method. As the thin sheet glass manufacturing method to eliminate such disadvantages, the sheet glass reforming method is known (for example, the Japanese Patent Publication No. 59-4383).
In this sheet glass reforming method, the material sheet glass of a thick wall (for example, thickness of 5 mm) is heated over the softening temperature, and it is drawn to reform the section thinly (e.g. thickness: 0.1 to 0.03 mm). According to this reforming method, by varying the feed speed of the material sheet glass, heating capacity, or pulling speed, a desired sheet thickness will be easily obtained.
The material sheet glass used in this sheet glass reforming method is preliminarily cut to a specific length, and each sheet is fed into the reforming device by chucking its upper end, and therefore the chucked portion is not heated and softened, and the rate of use of the material sheet glass is lowered by that portion. Besides, since the material sheet glass is intermittently fed into the reforming device one by one in a batch system, the temperature of the heating furnace may vary until the next material sheet glass is supplied, and the sheet drawing condition may be discontinuous, and hence it is difficult to obtain a homogeneous thin sheet glass.
SUMMARY OF THE INVENTION
It is hence a primary object of the invention to present a method of manufacturing thin sheet glass by heating the material sheet glass over the softening temperature, and drawing it out, wherein the front end of the next material sheet glass is sequentially fused to the rear end of the preceding material sheet glass in the feeding process.
In this way, the material sheet glass is continuously fed into the reforming device, and is drawn in the same condition. Therefore, loss of material sheet glass, loss time in production, and temperature fluctuations in the heating furnace can be eliminated, and therefore a homogeneous thin sheet glass can be continuously manufactured at a high efficiency.
In this invention, moreover, the upper end of the first material sheet glass is held by a first chuck, and is fed into the drawing process at constant speed while heating the lower end, and during this feed, the upper end of the first material sheet glass is transferred to a third chuck moving at the same speed, and the first chuck is moved back to hold the upper end of the second material sheet glass, and it is brought closer to the first material sheet glass, and the neighboring ends of the two glass sheets are heated and softened, and the lower end of the second material sheet glass is pressed and fused to the upper end of the first material sheet glass through cooperation of holding by a second chuck, and right after fusing, the fused portion is slightly pulled to release the holding of the second chuck and third chuck, and the upper end of the second material sheet glass is held by the first chuck to continue feeding, and during this feed, the upper end of the second material sheet glass is transferred to the third chuck, and thereafter the same action is repeated.
In this constitution, the third chuck holds the upper end of the material sheet glass first held by the first chuck to continue the feed of the same material sheet glass. In this period, the first chuck prepares the next material sheet glass to follow up the preceding material sheet glass.
The second chuck, when fusing the material sheet glass, holds the lower end of the next material sheet glass having its upper end held by the first chuck, and abuts against the upper end o
Itoi Hideyuki
Kaizuka Tsuneo
Yoshimura Ryoji
Nippon Electric Glass Co. Ltd.
Woodard Joye L.
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