What is the Production Method of Optical Glass?

As a Fused Silica Glass Supplier, share it with you. Glass that can change the direction of light propagation and change the relative spectral distribution of ultraviolet, visible or infrared light. Optical glass in a narrow sense refers to colorless optical glass; optical glass in a broad sense also includes colored optical glass, laser glass, quartz optical glass, anti-radiation glass, ultraviolet and infrared optical glass, fiber optical glass, acousto-optic glass, magneto-optical glass, and photochromic glass. Optical glass can be used to manufacture lenses, prisms, mirrors and windows in optical instruments. Components made of optical glass are key elements in optical instruments.

Optical Glass Blanks

The raw materials for the production of optical glass are some oxides, hydroxides, nitrates and carbonates, and phosphates or fluorides are introduced according to the requirements of the formulation. In order to ensure the transparency of glass, the content of colored impurities, such as iron, chromium, copper, manganese, cobalt, and nickel, must be strictly controlled. When ingredients are required, accurate weighing and uniform mixing are required. The main production processes are smelting, forming, annealing and inspection.

①Smelting: There are single crucible batch smelting method and continuous smelting method in tank kiln. Single crucible smelting method can be divided into clay crucible smelting method and platinum crucible smelting method. No matter what kind of smelting method is used, a stirrer is required to stir, and the temperature and stirring are strictly controlled to make

The molten glass is highly uniform. Clay crucible can smelt most crown glass and flint glass, with low cost, and is used when the melting temperature of the glass exceeds the service temperature of platinum. The platinum crucible can smelt high-quality glass that has a serious corrosive effect on the clay crucible, such as heavy crown, heavy barium flint, rare earth glass and fluorophosphorus glass. The platinum crucible is heated by electricity, generally using silicon-carbon rod or silicon-molybdenum rod electric furnace. However, high-frequency heating can be used to manufacture glass that has a high tendency to crystallize, requires rapid cooling, and has certain requirements on the atmosphere.

Since the 1960s, various countries have successively adopted continuous tank smelting lined with platinum, which greatly increased the output and quality of optical glass. This is the main trend in the development of optical glass production technology.

②The molding methods of molding optical glass include classical crucible method, rolling method and pouring method, but leakage molding (using single crucible or continuous melt flow out) is more and more widely used, which can directly draw rods or drop materials Pressing or leaking to form large-size blanks can improve the utilization rate of gobs and the yield rate.

③ Annealing 　 In order to eliminate the internal stress of the glass to the maximum and improve the optical uniformity, a strict annealing system must be formulated and precision annealing is performed.

④Inspection 　 The measured indicators are: optical constant, optical uniformity, stress birefringence, streaks, bubbles, etc.

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