Bi-concave glass lenses are manufactured with both surfaces concave. These lenses have negative focal lengths. These lenses diverge collimated incident light and form virtual images, which are seen through the lens. They are often used to expand light or increase focal lengths in existing systems. They are used in laser beam expanders, optical character readers, viewers, and projection systems. Antireflection coatings can be ordered as an option
Technical parameters:Wavelength 632.8nm,Focal length tolerance ±1%,Diameter tolerance +0.0/-0.1mm,Thickness tolerance ±0.1mm,Surface accuracy λ/4,Surface quality 40-20,Centration<3arcmin,clear aperture="">90%,Bevelling<0.2×45°,Coating A: AR Coating 350nm-650nm;B: AR Coating 650nm-1050nm;C: AR Coating 1050nm-1580nm.
