Both surfaces of the double concave lens are concave and have the same radius of curvature. A biconcave lens with a negative focal length is usually used to collimate a beam, increase (decrease) the focal length, or enlarge (reduce) the image.
Basic Technical Parameters
Tolerance of Dimension: ±0.05mm
Surface Accuracy: 1/2λ，λ/4 per φ25.4mm
Surface Quality: 60-40, 40-20, 20-10，10-5
Clear Aperture： >90%
Polish： High-precision Polish on Both Surfaces
Biconcave lenses are often used in systems to expand the beam of light or to increase the focal length, and can also be used in laser beam expansion, light readers, observers, and projection systems.