A lens has a refractive index of n, and includes a base, a first curved circumferential surface extending from the base, a curved center-edge surface extending from the first curved circumferential surface, and a curved centermost surface extending from the curved center-edge surface. The base includes a groove for receiving a light emitting chip. A distance from a center of the base to a point of the curved center-edge surface is shorter than the radius of curvature for the point of the curved center-edge surface. The curved centermost surface has a concave shape with respect to the base. The lens satisfies A1+A2