TFT-LCD glass substrate manufacturing method part two

The following is only the description of the above three process technologies as follows:

(1) Float method:

It is the most famous flat glass manufacturing technology at present. This method transports the molten glass paste in the furnace to the liquid tin bed. Because of its low viscosity, the thickness of the glass can be controlled by the baffle plate or the tie rod. As the glass paste increases, the glass paste is gradually solidified into flat glass, and then the solidified glass plate is led out by the guide wheel, and then it is formed by post-processing procedures such as annealing and cutting.

When using the float method to produce ultra-thin flat glass, it is necessary to control the low glass paste feed rate. First, the glass ribbon (R ibbon) entering the tin bed should be cooled to about 700°C. At this time, the viscosity of the glass ribbon is about 108 poise ( Poise; 1 poise = 1 g / cm•sec ), and then use the edge roller to pull the glass paste floating on the liquid tin, and after it is stretched out, the glass ribbon is heated to 850℃, and the external force is applied with the conveyor roller Pulled by.

The float process technology adopts the horizontal lead method, so it is easier to use the elongated horizontal production line to meet the annealing requirements. The main reason why the float process technology has not been widely used in the production of ultra-thin flat glass with a thickness of less than 2 mm is that it cannot achieve the required economic scale. For example, the daily output of float technology can almost meet the monthly consumption of the current Taiwan market; if the float technology is used to produce ultra-thin flat glass, it is generally produced in a discontinuous tank kiln (D a yTank). Therefore, it is very important to optimize the design of the slot kiln.

(2) Flow hole down-drawing method: As far as the special ultra-thin flat glass required for flat-panel tft display displays is concerned, many manufacturers use the flow hole down-drawing method for production. This method uses low-viscosity homogeneous glass paste to introduce platinum In the slot bushing groove made of alloy, the thickness of the glass is controlled by the force of gravity and the pull-down force and the size of the mold opening. The temperature and the size of the orifice together determine the glass output, and the flow hole The size of the opening and the draw-down speed jointly determine the thickness of the glass, and the temperature distribution determines the warpage of the glass.

The orifice down-drawing process can produce 5 ~ 20 metric tons of ultra-thin flat glass with a thickness of 0.0 3 ~ 1.1 mm per day. Because platinum metal cannot withstand high mechanical stress, most molds made of platinum alloys are generally used. However, the orifice is often deformed when it is subjected to external forces, which results in uneven thickness and surface flatness that cannot meet the specifications. Its disadvantages.

The flow hole down-draw method must be annealed in the vertical direction. If it is turned to the horizontal direction, it may increase the contact between the glass surface and the roller and the warping caused by horizontal conveying, resulting in a large increase in the defect rate. Such concerns make the construction of the furnace must adopt a design with high ceilings, and at the same time, the height required for annealing must be accurately considered, which greatly increases the difficulty of the project and is also reflected in the cost of building the plant.

(3) Overflow melting method:

A long-shaped fusion pump (Fusion Pump) is used to transport the molten glass paste to the center of the fusion pump, and then use the overflow method to transfer two overflowing glass pastes to the pump’s center. The lower part is combined into ultra-thin flat glass.

The use of this molding technology also requires a heavy mold, so the molten pump mold also faces the problems of deforming due to mechanical stress, maintaining the level of the molten pump, and how to stably drive the molten glass paste into the molten pump. Because the thickness and the quality of the glass surface of the super flat glass made by the overflow melting method are determined by the amount of glass paste delivered to the melting pump, its stability, levelness, the surface properties of the pump, and the quality of the glass.

The fusion overflow technology can produce ultra-thin glass substrates with dual original glass surfaces. Compared with the float method (only a single original glass surface can be produced) and the flow hole down-draw method (which cannot produce original glass surfaces), It can avoid post-processing processes such as grinding or polishing. At the same time, in the flat-panel display manufacturing process, there is no need to pay attention to the difference in the properties of the glass surface due to the original and different glass surfaces that are in contact with the liquid tin or the grinding media. And so on, has become the mainstream of ultra-thin flat glass forming.