The Double Concave Lenses are made from BK7 material, which 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. We will provide precision grade Double Concave Lenses with tighter manufacturing tolerances.Specifications:Material:BK7Design Wavelength:546.1nm, n=1.518721Diameter Tolerance: 0.0/-0.1mmParaxial Focal Length:±2%Centration:3 arc minutesSurface Figure :l/4 @ 632.8 nmSurface Quality:60/40Clear Aperture:>80%Bevel:<0.25mm X 45°Coating:Uncoated以上是透镜的详细信息，如果您对透镜的价格、厂家、型号、图片有什么疑问，请联系我们获取透镜的新信息。