LB1378 N-BK7 Bi-Convex Lens; Dia:0.5 in; f=40.0 mm Uncoated

The LB1378 N-BK7 Bi-Convex Lens is a high-quality optical component sourced from Thorlabs, a leading vendor in the field of precision photonics. This lens, with a diameter of 0.5 inches and a focal length of 40.0 mm, is designed for use in a wide range of optical systems, including imaging, beam shaping, and laser applications.

The lens is made from N-BK7, a type of borosilicate glass known for its excellent optical properties. This material is characterized by a high refractive index and low dispersion, making it ideal for applications that require high-precision optical performance. The lens is uncoated, which means it does not have any additional layers to enhance its optical properties. However, uncoated lenses can still provide excellent performance in many applications, especially where high transmission and low reflectivity are not critical.

The geometry of the lens is carefully designed to provide optimal performance. It has a diameter of 12.7 mm, with a thickness of 1.8 mm at the edge and 2.8 mm at the center. The lens features two convex surfaces, with radii of curvature of 40.7 mm and -40.7 mm, respectively. These surfaces focus light to a point determined by the lens's effective focal length (EFL) of 40.0 mm. The back focal length (BFL) of the lens is 39.1 mm, which is the distance from the rear surface of the lens to the focused light beam.