Glass that can change the direction of light propagation and the relative spectral distribution of ultraviolet, visible or infrared light. According to the optical properties, optical glass can be divided into colorless optical glass, anti irradiation optical glass, anti irradiation optical glass, colored optical glass, ultraviolet and infrared optical glass and optical quartz glass. Today we first want to know about the production process of optical filter. Details are as follows:
Some oxides, hydroxides, nitrates and carbonates are used in the production of optical glass, and phosphate or fluoride are introduced according to the requirements of the formula. In order to ensure the transparency of glass, it is necessary to strictly control the content of coloring impurities, such as iron, chromium, copper, manganese, cobalt, nickel, etc. Accurate weighing and uniform mixing are required during batching.
The primary production process is smelting, forming, annealing and inspection.
① There are single crucible batch melting and continuous melting in tank furnace (see furnace). Single crucible melting method can be divided into clay crucible melting method and platinum crucible melting method.
② The forming methods of forming optical glass include classical broken crucible method, rolling method and pouring method, but now more and more widely use leakage forming (using single crucible or continuous melting liquid), which can directly pull rod or drop material to press or leak material to form large-size blank, improve the utilization rate of material drop and product rate.
③ Annealing in order to eliminate the internal stress of glass to the maximum limit and improve the optical uniformity, it is necessary to formulate a strict annealing system and carry out fine annealing.
④ The objectives of inspection and determination are: optical constant, optical uniformity, stress birefringence, fringes, bubbles, etc.