Dense Lanthanum Flint Glass
Dense Lanthanum Flint Glass is referred to as ZLaF glass. It is located on LaF glass in the nd-v diagram. ZLaF glass with nd between 1.80 and 1.90 is based on La2O3, Ta2O5, ZrO2-B2O3, and the part with nd above 1.90 needs to be added with Nb2O5, so it is also called niobium-tantalum glass. The main disadvantage of this type of glass is its poor chemical stability, and it must be protected by a coating on the surface during use. Mainly used for high-quality photographic objectives.
By modifying the glass formula, the optical glass without lead, arsenic and cadmium and other radioactive elements is expressed by a prefix "H-" indicating its envioronment-friendly characteristics, for example: H-ZLaF52.
