50.8mm glass biconcave glass optical lens

The image formed by biconcave lens is always smaller than the vertical virtual image of the object. Biconcave lens is mainly used to correct myopia. Myopia is mainly due to the deformation of the lens, resulting in the premature collection of light in front of the retina. The biconcave lens plays the role of divergent light. The biconcave lens becomes an upright and reduced virtual image, which lengthens the image distance and just falls on the retina.

Material: K9, BK7, FS, UVFS, CaF₂, ZnSe

Diameter:3mm-200mm±0.05mm

Center Thickness Tolerance:±0.05mm

Lens Alignment Error:≤3min

Surface Accuracy:λ/ 10 @

Surface Quality:40/20. 60/40. 80/60

Effective Caliber: 90%

Example with BK7 material：These N-BK7 biconcave lenses are available uncoated or with one of five antireflection coatings (-A, -AB, -B, -C, or -D), which reduces the amount of light reflected from each surface of the lens (see the Selection Guide table below for coating option). Since approximately 4% of the incident light is reflected at each surface of an uncoated substrate, the application of an AR coating improves transmission, which is important in low-light applications, and prevents the undesirable effects (e.g., ghost images) associated with multiple reflections. Having optics that are AR coated on both surfaces is particularly desirable for applications utilizing multiple optical elements. Please see the Graphs tab for additional coating information.

N-BK7 bi-Concave Lens Selection Guide
Coating name	wavelength band
Uncoated	Uncoated
A Coating	350nm-700nm
AB Coating	400nm-1100nm
B Coating	650nm-1050nm
C Coating	1050-1700nm
D Coating	1650nm-3000nm

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