47-640 25 mm Dia. N-SK11/N-SF5 Achromatic Doublet; EFL=85mm VIS 0° 425-675nm

The 47-640 is a high-quality achromatic doublet lens, boasting a 25 mm diameter and an effective focal length of 85 mm, specifically designed for the visible light spectrum ranging from 425 to 675 nm. This lens is sourced from the renowned optical vendor, Edmund Optics, and is available for purchase through their official website.

The lens is constructed from two types of Schott glass, N-SK11 and N-SF5, which are carefully selected to minimize chromatic aberration, a common issue in optical systems. The front and back surfaces of the lens are coated with the EDM VIS-0 standard curve coating, further enhancing its performance by reducing surface reflections and increasing transmission.

The lens geometry is meticulously designed, with a thickness of 6.05 mm at the edge and 5.01 mm at the center. The first and second radii of curvature are 55.68 mm and -38.37 mm, respectively, while the third radius of curvature is -146.45 mm. The lens features an inner radius of 0 mm and an outer radius of 0 mm, indicating a symmetrical design.

This lens is a multiplet, meaning it is composed of multiple elements, which allows for more precise control over optical properties. The lens is available in stock, making it a reliable choice for immediate integration into optical systems.