公开(公告)号：JPH02240625A

公开(公告)日：1990-09-25

申请号：JP2431890

申请日：1990-02-02

Applicant: ESSILOR INT

Inventor： KURISUCHIYAN MIEEJIYU ,  PIEERU MONTEIYU ,  JIERAARU OBUREEKU

IPC: A61F2/14 ,  A61F2/16 ,  G02C7/04 ,  G02C7/06

Abstract: PURPOSE: To clearly observe an object existing in any range by preparing a curve expressing a proximity value in a limit value range specific to an increment required by a user as a function of a distance from an optical axis. CONSTITUTION: A curve expressing a proximity value P defined as the inverse of a diopter D to be a position existing in a simultaneous visual field optical lens for correcting presbyopia, parallel with the optical axis A and intersecting with the optical axis A after the passage of light F with a distance (h) from the axis A through the lens is defined by n-th order and h-th order polynomials. The curve exists in an area between a lower envelope curve Pint and an upper envelope curve Psup satisfying the equation I. Provided that P is a proximity value necessary for a far visual field and A'i A"i are the coefficients of various polynomials depending upon the value of the increment δ1 =ADD of the proximity value corresponding to the degree of user's presbyopia. Consequently the user can clearly observe an object existing in any range (a far range, an intermediate range, the shortest range).