Patent ID: 6074061
Filing Date: 2000-06-13
Classification: G02C

Abstract:
A progressive focal lens comprising:a distance area located at an upper portion of said lens;a reading area located at a lower portion of said lens;a progressive area located between said distance area and said reading area;a principal meridional line extending vertically at a center portion of said lens and crossing said distance area, said reading area and said progressive area, a nose-side area and an ear-side area being defined on opposing sides of said principal meridional line, a part of said principal meridional line in said progressive area and said reading area being shifted to said nose-side area from said center portion of said lens; anda plurality of equi-astigmatism curves arranged in said nose-side area and said ear-side area, wherein an astigmatism increases as said each equi-astigmatism curve is move away from said principal meridional line into said nose-side area and said ear-side area, and in at least one of said progressive area and said reading area, said equi-astigmatism curves in said ear-side area are asymmetrical to those in said nose-side area, and an increase in astigmatism in said nose-side area is smaller than an increase in astigmatism in said ear-side area, wherein a distortion occurs in said nose-side area and said ear-side area, and the distortion in said nose-side area is smaller than the distortion in said ear-side area in at least one of said progressive area and said reading area.