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 |
Other series products：
Concave lens Achromatic Lens Ball Lens Silicon Window Zinc Selenide Window Wedge Optical Window
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