Concave lenses are less common than convex lenses in optical engineering, but they still have some useful applications. Some examples of devices that use concave lenses are eyeglasses, peepholes ...

Source: NOVA: "Galileo's Battle for the Heavens" This resource was adapted from NOVA: "Galileo's Battle for the Heavens." As early as the 1300s, eyeglasses made from convex, or outward-curving ...

US researchers have engineered a concave photonic crystal microlens that they claim provides the shortest focal length ever achieved for infrared light. The team from Northeastern University hopes to ...