Optiikkalasi

Optiikkalasi, or optical glass, is a silica-based glass engineered for precise optical performance in lenses, prisms, filters, and other light-transmitting components. Unlike common soda-lime glass, optical glass is formulated to have specific refractive indices, dispersion, and transmission characteristics across defined spectral ranges.

Most optical glasses are grouped into crown glasses, which have relatively low refractive index and low dispersion, and flint glasses, which have higher indices and greater dispersion. Special glasses are designed for UV or infrared transmission, high or low dispersion, or low thermal expansion. Common materials include BK7 (a borosilicate crown glass), F-series and SF-series flints, and fused silica for UV transparency. Doping with metal oxides tunes refractive index, dispersion, and color.

Key properties to specify are refractive index n_d at the standard sodium D line and the Abbe number V_d, along with transmission range, chemical durability, and thermal stability. Homogeneity and internal stress are also important for high-precision optics.

Manufacture involves melting silica with additives, forming the glass, and annealing to relieve stress. After fabrication, components are tested and sorted into catalog codes with documented optical performance. ISO and national standards guide classification and quality control.

Typical applications include camera and consumer lenses, eyeglass and microscope optics, telescope prisms and windows, laser optics, and scientific instrumentation.