convex lens-it focuses light rays, and therefore is also known as a converging lens. The focal point is the point where the light rays meet.These types of lenses are thicker in the middle than in comparison to their edges. Due to this structure, it is able to converge the light rays.
concave lens-A concave lens is just the opposite of a convex lens. It is thinner in the middle and thicker at the edges.it diverge all the light rays. Therefore, it is known as diverging lens.