Rare earth element optical glass

Thirty years there have been new rare earth elements of optical glass, the main component is lanthanum, thorium, tantalum oxide. Rare Earth Elements Optical glass has a high refractive index, opening up new possibilities for the design of optical lenses. Today there are many large-aperture lens lanthanum glass. Thorium glass because of radioactive, has stopped production.

Lead - free optical glass

Lead-free optical glass does not contain lead, arsenic, marked with N.