Plano-convex lenses, convex on one side and flat on the other, with a positive focal length, are commonly used in related applications such as reducing the beam, reducing the focal length, or enlarging an image. In order to reduce spherical aberration, when collimating the beam with a plano-convex lens, the beam should be incident on the surface of the lens. When used for point source collimation, the beam is incident on a plane. Plano-convex lenses have a positive focal length and are commonly used in applications such as imaging or beam collimation, while coated lenses are also widely used in visible and near-infrared applications.

Plano-convex lenses focus parallel rays of light into a single point, which is the focal point of the lens. It is characterized by a positive focal length where one is flat and the other is convex. When used, the convex surface is usually toward the incident light, because the refractive index of the light is slightly different on both sides of the plane mirror, so the focal length on both sides is different, in order to reduce the spherical difference, the beam should be as far away from the curved surface incident as possible. Plano-convex lenses are often used to aim and focus monochromatic light sources, to converge parallel light, or to convert divergent point light sources into parallel light. The asymmetric properties of plano-convex lenses can reduce spherical aberrations when the distance between the image and the objective lens is not equal. Usually, a parallel beam (or distant source) is incident from a convex plane to minimize the occurrence of spherical aberrations, and the beam emitted from the plane side is collected. Plano-convex lenses are used for focusing optical systems and collimating diffuse beams. The sharpest focus is achieved when the curved part of the lens is directly facing the object. Plano-convex lens has positive focal length and positive direction, which plays a key role in imaging quality.

Plano-convex lenses, commonly used in imaging or beam collimation applications, coated lenses are also widely used in visible and near-infrared applications. Plano-convex lenses play an important role in astronomy, military, transportation, medicine, art and other fields.