The 88-654-INK is a Plano-Convex lens, a type of spherical lens, sourced from Edmund Optics. This lens, with a diameter of 9.0mm, is designed for use in the visible light spectrum, specifically between 350-700nm, as indicated by its VIS-EXT coating on both the front and back surfaces.
The lens's geometry is characterized by its edge thickness of 1.25mm and center thickness of 2.41mm. The effective focal length (EFL) is 18mm, and the radius of curvature (R1) is 9.32mm. The back focal length (BFL) is 16.41mm, and both the inner and outer radii are 0mm.
The lens is made from N-BK7 Schott, a popular optical glass due to its excellent optical properties and relatively low cost. The lens's shape is spherical, a common choice for its ease of manufacturing and versatility.