Konveksläätsi

Konveksläätsi (Estonian: convex lens) is a curved glass or plastic element that focuses or diverges light rays by refraction. The refracting surface bulges outward, giving the lens a thicker center and thinner edges. Because of this geometry, parallel rays incident on a convex lens converge to a point called the focal point, unless the lens is in a medium of equal refractive index, in which case it has no optical power.

The power of a convex lens is measured in diopters and is the reciprocal of its focal length expressed in meters. A lens with a short focal length (high diopter count) bends light strongly and is used in magnifying glasses and camera lenses for close‑up imaging. Lenses with a long focal length (low diopter count), such as those used in telescopes, provide weak magnification over large fields of view.

Convex lenses are employed in many everyday devices. Eyeglasses correct hyperopia (farsightedness) by tightening the image formed on the retina. Camera lenses combine several convex elements with concave lenses to achieve sharp, aberration‑controlled images across wide telephoto and wide‑angle ranges. Projectors use convex lenses to focus an image onto a screen, while magnifying glasses and medical instruments such as endoscopes rely on them for enlarging tiny details.

Different lens shapes—biconvex, plano‑convex, meniscus—offer variations in optical behavior. The biconvex shape is common for simple magnification, whereas the plano‑convex shape is often preferred when a flat side is needed for mounting. Meniscus lenses, with one convex and one concave surface, can reduce spherical aberration when properly designed.

Overall, a convex lens serves as a fundamental component in optical science, enabling the manipulation of light for vision correction, photography, scientific instrumentation, and everyday tools.