The 47-889 is a Plano-Convex Lens, a type of spherical lens, sourced from Edmund Optics. This lens has a diameter of 20.0mm and a focal length of 70.0mm, making it suitable for a variety of optical applications. The lens is made from n-BK7 Schott, a high-quality optical glass known for its excellent transparency and low dispersion.
The lens features a standard coating on both the front and back surfaces, specifically the "edm vis-0 std curve" coating. This coating is designed to improve the lens's performance in the visible light spectrum, particularly between 425 and 675nm. The coating helps to reduce surface reflections, thereby increasing the amount of light transmitted through the lens.
The geometry of the lens includes a thickness of 1.59mm at the edge and 3.0mm at the center. The inner and outer radii are both 0, indicating a simple, straightforward design. The lens's effective focal length (EFL) is 70.0mm, and the back focal length (BFL) is 68.03mm. The radius of curvature of the first surface (R1) is 36.18mm.