Double-Concave LensesFeatures:High Precision Dimension Control,Optional Substrate Material,Diverges incident light Lower spherical aberrations than for Plano-Concave lenses, Ideal for Experimenting and Prototyping ApplicationsApplications:Image Reduction and to Spread Light, Laser beam expanders, Optical character readers, Optical Viewers, Projection Systems, Imaging Systems, Laser Measurement Systems.Description:A double-concave lens is compose of two concave surface, has a negative focal length and are best used to diverge a converging beam. Similar to a plano-concave lens, a bi-concave lens can diverge a collimated beam to a virtual focus like a beam expander.Double concave (DCV) or Biconcave lenses are symmetrical with equal radii of curvature on both sides. The biconcave lenses are used in optical systems in combination with other lenses. These lenses also work as beam expanders, optical character readers, viewers and projection systems.With its two concaves surface, the biconcave lens refracts light efficiently in a small space and spread widely the light.Possible to use it for enlarging the illumination area.Double Concave Lenses are used in beam expansion, image reduction, or light projection applications. These lenses are also ideal for expanding the focal length of an optical system. Double Concave Lenses, which have two concave surfaces, are Optical Lenses with negative focal lengths.Specification:Material: BK7, Fused Silica, SF10, CaF2, Sapphire. etc.Paraxial Focal Length Tolerance: ±2%Dimension Tolerance: ±0.2(General). ±0.05(High Precision)Centration: <3 arc minIRR: λ/4@633nm（General),λ/10@633nm(High Precision)Clear Aperture: >80%(Small Size), >95%(Laege Size)Surface Figure: <1.5λ@633nm（General),<λ/4@633nm(High Precision)Surface Quality: 60/40（General),10/5(High Precision)Bevel: <0.25mmCoating: Uncaoted, AR,PR, HR, etc.
