85-878 50 mm Dia. N-FK5/F2HT Achromatic Doublet; EFL=100mm UV-VIS 345-700nm

The 85-878 is a high-quality Achromatic Doublet lens, boasting a 50 mm diameter and an effective focal length (EFL) of 100mm, specifically designed for UV-VIS 345-700nm applications. This lens is sourced from the renowned optical vendor, Edmund Optics, and is available for purchase on their official website.

The lens is constructed from two types of materials, N-FK5 and F2HT, both from Schott. The N-FK5, used for the first element, is a high-index, low-dispersion glass, while the F2HT, used for the second element, is a low-index, high-dispersion glass. This combination effectively reduces chromatic aberration, ensuring sharp and clear images across the entire UV-VIS spectrum.

The lens geometry is meticulously designed, with a diameter of 50 mm, a thickness at the edge of 12.86 mm, and a center thickness of 16 mm. The first and second radii (r1 and r2) are equal in magnitude but opposite in sign, measuring 50.95 mm, which contributes to the lens's achromatic properties. The third radius (r3) is -197.88 mm, further enhancing the lens's optical performance.

The lens is coated with the EDM UV-VIS STD curve on both the front and back surfaces, providing excellent transmission and protection against environmental factors. The lens is available in a multiplet shape, making it suitable for a wide range of optical systems and applications.