Heavy lanthanum flint optical glass

Abstract

The invention provides heavy lanthanum flint optical glass with refractive index being 1.82 to 1.87 and abbe number being 28 to 32. The heavy lanthanum flint optical glass is prepared from the following components in percentage by weight: SiO2, TiO2, ZnO, Nb2O5, Al2O3, RO, B2O3 and La2O3, wherein (SiO2+RO) / (La2O3+B2O3) is 4 to 15; Nb2O5 / TiO2 is 1.2 to 3; TiO2 / (B2O3+Al2O3) is 2 to 20; and B2O3 / ZnO is 0 to 0.3. Through reasonable component proportioning and under the condition that the optical property index is guaranteed, the glass is suitable for continuous melting production of ceramic platinum which is melted for once, and has high transmittance. After the glass provided by the invention is subjected to heat preservation in a muffle furnace at the temperature of Tg+230 DEG C for 30 minutes, the surface of the glass is not crystallized obviously, so the glass is particularly suitable for application which needs to perform long-time plastic operation near a softening point.

Description

technical field [0001] The invention relates to a high-refractive-index optical glass, in particular to a heavy lanthanum flint optical glass with a refractive index of 1.82-1.87 and an Abbe number of 28-32. The rate is high, and it has good anti-devitrification performance in the process of reheating and shaping. Background technique [0002] In the prior art, glass with a refractive index of 1.82-1.87 and an Abbe number of 28-32 belongs to the high-refractive index heavy lanthanum flint glass, and B 2 o 3 (SiO 2 )-La 2 o 3 -TiO 2 -RO glass system (R refers to Mg, Ca, Sr, Ba), in which B 2 o 3 with La 2 o 3 Higher content, such as the glass described in CN3149039.5, CN200810081055.4, US5288669 (A). The viscosity of the glass in this system is very small in the dissolved state, generally less than 1.0dpas at a temperature of 1200°C. In addition, due to its strong corrosion ability to fused zirconia corundum bricks, such as quartz, zirconium corundum and other mate...

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Problems solved by technology

It has the following disadvantages compared with the continuous smelting production method of porcelain platinum primary chemical material: 1) The production process requires two chemical materials, the first time is that glass powder is melted into glass liquid in a platinum crucible, and then poured into glass slag The second time is to dissolve the glass slag into molten glass in the continuous melting platinum chemical tank, and the energy consumption is about 30% higher than that of the primary chemical material; 2) In the production process of optical glass, the corrosion of platinum by the glass in the chemical material stage The ability is the strongest, especially in the process of melting the powder into glass liquid, a large number of platinum ions entering the glass will cause a sharp drop in the transmittance of the glass in the ultraviolet-blue light band; Compared with the glass produced by continuous melting of primary chemical materials, the platinum consumption of the former to produce 1 kg of products is about 40% higher than that of the latter, and a large number of glass slag classification, storage and testing processes and costs are increased.

[0004] In addition, B 2 o 3 (SiO 2 )-La 2 o 3 -TiO 2 -The crystallization resistance performance of the RO system glass is poor during the reheating plastic process, and the surface is completely devitrified in the test at Tg+230°C for 30 minutes

This limits the application of this type of glass in long-term plastic operations near the softening point, such as drawing optical fibers, repeated heating and plasticizing of complex parts, etc.

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