GRADUALLY ADDITIONAL TYPE LENS

摘要

PROBLEM TO BE SOLVED: To decrease undesired astigmatism so as to increase channel width from a middle field area to a near field area by combining a gradually additional surface having 1st refractive power with at least one optical element additionally giving additional refractive power to a lens. SOLUTION: An optical preliminary molding body is constituted of the near field area and the gradually additional surface having 1st additional refractive power or mainly constituted of them or constituted only of them. At least one of one or more optical elements is arranged to be superposed on the near field area and the additional refractive power of the lens is the sum value of the 1st additional refractive power and the 2nd additional refractive power. The gradually additional surface is arranged on the projected or recessed surface of the optical preliminary molding body. The additional refractive power of the gradually additional surface is set within the range of about +0.01 diopter to about +3.00 diopter, desirably, about +1.00 diopter to about +2.75 diopter.