Double-convex lens, a special kind of positive lens, also called biconvex lens, is used to converge incident light to a spot (focal point) on the axis. It can form both real images and virtual images(for magnifier) on the two sides. Symmetric-convex lenses have two convex surfaces with identical radii. It is most suitable for where the object and image are on opposite sides of the lens and the ratio of the image and object distances(conjugate ratios) is between 0.2 to 5. The materials can be BK7, Fused Cilica, sapphire and CaF2 etc., for different applications. Bi-convex lenses are usually used in many devices of beam expanders,. Projection optics systems, optical viewers etc. Antireflection or other coatings can be ordered for some special applications.

Material--------------------BK7 Grade A or equivalent optical glasses

Design Wavelength-------480-650nm

Diameter Tolerance-------±0.1mm, ±0.15mm for Dia.≥75mm

Paraxial Focus Length-----±2% @546.1nm

Centration-----------------<3 arc minutes

Clear Aperture------------->80%

Surface Figure-------------λ/4 @632.8nm

Surface Quality------------60/40～40/20 scratches and dig

Coatings-------------------Antireflection coatings or NIR coatings

Bevel-----------------------A slight protective bevel

(For different applications, there are various choices in the specifications, which must be determined according to users’ specific requirements.)