| 摘要 |
The invention is directed to optical elements that are coated with dense homogeneous fluoride films and to a method of making such coated elements. The coatings materials are a high (“H”) refractive index fluoride material and a low (“L”) refractive index material that are co-evaporated to form a coating layer of a L-H coating material (a co-deposited coating of L and H materials). Lanthanide metal fluorides (for example, neodymium, lanthanum, dysprosium, yttrium and gadolinium, and combinations thereof) are preferred metal fluorides for use as the high refractive index materials with lanthanum fluoride (LaF3) and gadolinium fluoride (GdF3) being particularly preferred. Aluminum fluoride (AlF3) and alkaline earth metal fluorides (fluorides of calcium, magnesium, barium and strontium) are the preferred low refractive index materials, with magnesium fluoride (MgF2) being a preferred alkaline earth metal fluoride. |
