What is a Double Concave Lens?

1. Introduction to double concave lens


A double concave lens is also called a negative spherical lens. The middle of the lens is thin, the edge is thick, and it is concave, so it is also called a concave lens, which has a divergent effect on light.


The imaging law of the concave lens is: when the object is a real object, it becomes an upright, reduced virtual image, and the image and the object are on the same side of the lens. The concave lens has a divergent effect on the light, so the lens is also called a divergent lens, a negative spherical lens.


2. Features of biconcave lens:


A double concave lens is concave on both sides and has the same radius of curvature. A double concave lens with a negative focal length is usually used for beam collimation, increasing (decreasing) the focal length or enlarging (shrink) the image.


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.


3. Double concave lens parameters:


Optional materials: K9, N-BK7, JGS series UV fused silica


Working range: 400 nm-700 nm (other bands can be customized)


Design wavelength: 546.1nm (n=1.519)


Tolerance of focal length: ±2%


Shape tolerance: +0.0/-0.02mm


Thickness tolerance: ±0.02mm


Curved aperture: 3


Plane flatness (aperture): 1


Surface local aperture: 0.5


Eccentricity: ≤3 arcmin


Surface type: λ/4@632.8nm


Surface finish: National standard three, U.S. military standard 60-40


Clear aperture: >90%


Safe beveling: <0.2X45°

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