Relatively thin lens with negative refractive power for use in spectacles - has aspherical surface which is rotationally symmetrical and visibly convex

摘要

The aspherical lens (1) for spectacles has a negative refractive power and the object side surface is aspherical and rotationally symmetrical. The refractive power of the aspherical surface in the central region around the axis of rotational symmetry has a value of approximately 0 dioptres and the aspherical surface is visibly convex. The aspherical rotationally symmetrical surface has a positive refractive power which increases with increasing distance from the axis of rotational symmetry but is slightly reduced in the region of the lens rim. The lens is made from a material with a refractive index which is equal to or greater than 1.65. USE/ADVANTAGE - Relatively thin lens with negative refractive power for use in spectacles.