One side of the meniscus lens is convex and one side is concave. It can be a convergent lens or a divergent lens, which is determined by the refractive index, curvature and radius. It can be used in projection system, imaging system and laser measurement system.

The meniscus lens includes a positive meniscus lens and a negative meniscus lens. The positive meniscus lens is used to reduce the focal length of another lens while maintaining the angular resolution of the optical components. Its materials include K9, UV fused quartz, CaF2, and ZnSe. These lenses are usually paired with another positive lens to obtain better focusing effect.

## About positive meniscus lens

The positive meniscus lens is composed of two curved surfaces with similar radius of curvature and has positive focal length. It is usually used to reduce the focal length of another lens, increase the numerical aperture and other related applications. In order to reduce spherical aberration, the beam should be incident on the convex surface of the lens when expanding or shrinking the beam or diverging collimated light is applied; When used for convergence collimation, the beam is incident on the concave surface.

Positive meniscus lens is mainly used to minimize spherical aberration. When combined with another lens, the positive meniscus lens can reduce the focal length and increase the system numerical aperture (NA) without introducing obvious spherical aberration. When used to converge parallel light, in order to minimize the spherical aberration, the R-plane of the lens should face the direction emitted by the light source. The coated lens is also widely used in visible and near-infrared applications.

### Features of positive meniscus lens:

Positive meniscus lens is a kind of meniscus lens. Its shape is similar to concave convex lens, but the meniscus lens is composed of two spherical surfaces with small radius of curvature and little difference in values. Meniscus lens is a concave convex lens used in CO2 laser and infrared optical system. Concave convex lens can reduce spherical aberration and produce the minimum collimated light focus. The positive meniscus lens is used to reduce the focal length of another lens while maintaining the angular resolution of optical components. Its materials include BK7, UV fused quartz, CaF2, ZnSe, etc.

## About negative meniscus lens

Negative meniscus lens is a kind of meniscus lens, also known as negative focal length meniscus lens. Its shape is similar to concave convex lens, but the center of negative meniscus lens is thinner than the periphery, while the center of positive meniscus lens is thicker than the periphery. The design purpose of the negative meniscus lens is to minimize the spherical aberration. The negative meniscus lens is composed of a convex surface and a concave surface, and the concave surface has a larger radius of curvature. The combination of the negative meniscus lens and another lens will reduce the numerical aperture of the system. The negative meniscus lens is a common optical element in the beam expansion system.

### Features of negative meniscus lens:

Negative meniscus lens is composed of two curved surfaces with similar radius of curvature and has negative focal length. It is usually used for beam expansion, increasing focal length and reducing numerical aperture. In order to reduce spherical aberration, in the application of beam expansion or divergent collimation light, the beam should be incident on the lens door: when collimating with dry convergence, the beam should be incident on the concave surface

Come on. Negative meniscus lens is mainly used to minimize spherical aberration. When combined with another lens, the positive meniscus lens can increase the focal length and reduce the system numerical aperture (NA) without introducing obvious spherical aberration. The coated lens is also widely used in visible and near-infrared applications. Dry for meniscus lens

The concave convex lens of CO2 laser and infrared optical system can reduce the spherical aberration and produce the minimum collimated light focus. The positive meniscus lens is used to reduce the focal length of another lens while maintaining the angular resolution of optical components. Its materials include BK7, UV fused quartz, CaF2, ZnSe, etc. Negative meniscus lenses are commonly used in infrared applications. These lenses have larger concave side curvature and smaller convex side curvature, which can be used to replace other negative lenses.

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