| 摘要 |
PROBLEM TO BE SOLVED: To provide a spectacle lens of which the appearance is not bad and which is suitably put in a frame by providing an optical effective part which is formed without depending upon the diopter and has a specific diameter, making the radius of curvature of the peripheral part larger than that of the refracting surface of the optical effective part, and making the optical effective part and peripheral part equal in the primary diffraction value of a sectional curved line. SOLUTION: This lens has the optical effective part ED which is formed at the center part of an eye-side refracting surface without depending upon the diopter and has a >=30 mm diameter and the peripheral part which is formed on the eye-side refracting surface smoothly continuously to the outer periphery. The radius RS of curvature of the refracting surface of the peripheral part is larger than the radius R2 of curvature of the refracting surface of the optical effective part ED. At the join part between the optical effective part ED and the peripheral part, their sectional curved lines are equal in primary differential value. The lens which has a superior outward appearance is obtained while the large external diameter is secured by smoothly connecting the curved surfaces of the optical effective part ED and peripheral part at the center part.
|
