N-BK7 Bi-Convex Lenses, Uncoated/AR350-1700nm

N-BK7 Bi-Convex Lenses, Uncoated, 350-2000nm/AR350-1700nm

Biconvex lenses feature positive focal lengths and efficiently focus parallel light to a precise focal point, offering similar focusing capabilities to plano-convex lenses. With dual spherical surfaces designed to the same curvature radius, these lenses naturally minimize spherical aberration. Due to their symmetrical structure, biconvex lenses are the ideal choice for applications with equal or near-equal object and image distances at 1:1 magnification, effectively reducing spherical aberration while canceling coma, distortion and chromatic aberration simultaneously. They deliver optimal low-aberration performance when the conjugate ratio falls between 5:1 and 1:5; for magnification beyond this range, plano-convex lenses are generally more suitable.

Tuniu biconvex lenses are manufactured from premium N-BK7 borosilicate crown glass, the most widely used optical glass offering reliable performance and cost advantages. N-BK7 provides excellent uniformity, low bubble and impurity content, and easy processing, making it well suited for visible and near-infrared applications. It is a cost-effective alternative to UV fused silica for applications that do not require high ultraviolet transmittance or ultra-low thermal expansion coefficients.

Available in a standard 25.4 mm diameter, our biconvex lenses are offered in uncoated and double-sided anti-reflection (AR) coated options. Uncoated lenses feature a wide spectral range and high laser damage threshold, while AR coatings are optimized for 350–700 nm, 650–1100 nm and 1050–1700 nm wavelength bands. The AR coatings reduce single-sided average surface reflectivity to less than 0.5%, greatly improving overall lens transmittance. Customized sizes and coatings are available upon request.

Parameters

Model

N-BK7 Bi-Convex Lenses, Uncoated, 350-2000nm, AR350-700nm/650-1100nm/1050-1700nm

Mounted in SM1 Lens Tube/Unmounted