Spherical lens element

plasticasphericalanti-reflective

Features Material: Optical-Grade Plastic Outer Diameters of 6.28 mm and 7.40 mm Available Effective Focal Lengths from 4.60 mm to 18.15 mm AR Coated for 400 - 700 nm (-A Coating) Our Plastic Aspheric Lenses, which are available uncoated or with an antireflection coating for the 400 - 700 nm range deposited on both sides, utilize molding technology to produce all-plastic, near-diffraction-limited optics. Designed by Philips for high-volume applications at affordable prices, these optics are ideal for low-power applications requiring lightweight components. The surface of the aspheric lens is designed to eliminate spherical aberration, which allows for the spot size and collimation of a monochromatic beam of light to be diffraction limited. In laser diode systems, difficulties with aberration correction are compounded by the beam's high divergence angle. Since individual spherical lenses can refract light at only small angles before spherical aberration is introduced, three or four elements are often required to collimate laser diode light. In contrast, a single aspheric lens collimates without introducing spherical aberration. When used to collimate or focus light, the lens should be oriented so that the side with a larger radius of curvature (i.e., the flatter surface) faces the point source.http://img.directindustry.com/images_di/2ai/save-En.gif