What type of lens converges light rays?

The type of lens that converges light rays is a convex lens. Its surface curves outward, making it thicker at the center than at the edges. When parallel rays enter an ideal convex lens, refraction bends them toward the principal axis, bringing them together at a focal point on the far side.

The converging behavior comes from refraction: light changes direction when it passes between air and the transparent lens material. The exact focal length depends on the lens’s curvature and refractive index. A convex lens can form either real or virtual images, depending on how far the object is from the lens. Cameras, magnifying glasses, microscopes, projectors, and the human eye all use converging optical elements.

“Convex” describes the outward-curving shape, while “converging” describes the lens’s optical effect. A concave lens is thinner in the middle and normally spreads parallel rays outward, so it is called diverging. Cylindrical lenses can focus light in only one direction and are used for purposes such as correcting astigmatism.