GRADIENT-INDEX MULTIFOCAL LENS

Title:

GRADIENT-INDEX MULTIFOCAL LENS

Document Type and Number:

WIPO Patent Application WO/1997/011401

Kind Code:

A1

Abstract:

A gradient-index multifocal lens belonging to a group designed onthe basis of predetermined rules so that basic factors of gradient-index multifocal lenses, such as a far focal measurement position F and a nearfocal measurement position N, can be adapted to lenses for eyeglasses. Suppose that surface refractive power (in diopters) at the measurement position F is a base curve (Bi), that the difference in the surface refracting power between the measurement position F and the measurement position N is Di (in diopters), and that the width of a region is W(Di, Bi), where the value of surface mean additional refracting power along a sectional curve in a horizontal direction passing below the measurement position N is at least Di/2. When any two gradient-index multifocal lenses of Di=Da and Bi=B1, B2 are extracted from the group of the multifocal lenses, they satisfy the relation W(Da, B1) > W(Da, B2) when B1 > B2. Accordingly, a gradient-index multifocal lens with a wide field by view desirable to users of eyeglasses is provided without increasing the time and cost of prescription production.

Inventors:

KITANI AKIRA

Application Number:

PCT/JP1996/002689

Publication Date:

March 27, 1997

Filing Date:

September 19, 1996

Export Citation:

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Assignee:

HOYA CORP (JP)
HOYA LENS CORP (JP)

International Classes:

G02C7/02; G02C7/06; (IPC1-7): G02C7/06

Foreign References:

JPS5958415A	1984-04-04
JPS54143245A	1979-11-08
JPH0720410A	1995-01-24

Other References: