Home > NEWS > What is a Double Concave Lens?
A double concave lens, also known as a biconcave lens, is a type of lens that has two concave (curving inward) surfaces. This means that the lens is thinner in the center and thicker at the edges, creating a negative lens that diverges light rays.
A biconcave lens has a concave shape on both sides and features the same radius of curvature. Its negative focal length makes it useful for beam collimation, as well as for increasing or decreasing the focal length, and enlarging or shrinking images.
The double concave lens has a negative focal length and is often used in imaging or beam collimation applications. The coated lens is also widely used in visible light and near-infrared applications.
Conventional lens sizes are: Φ12.7mm, Φ25.4mm, Φ50.8mm, and customized double convex lenses can be produced according to customer project requirements.
Our factory biconvex lens have a diameter tolerance of < + 0.00/ - 0.02mm and a flatness of < λ/5 @ 633nm. Focal length tolerance can be achieved < ± 1%
|Surface Flatness||< λ/5 @ 633nm|
|Scratch/Dig||< 40/20 (both sides)|
|Focal Length Tolerance||< ± 1%|
|Diameter Tolerance||< + 0.00/ - 0.02mm|
|Thickness Tolerance||< ± 0.05|
|Clear Aperture||≥ 95% of diameter|
|Coating||AR OR BBAR|