Diffraction-type multifocal ophthalmic lens and manufacturing method thereof

摘要

Provided is a diffraction-type multifocal ophthalmic lens for which halos are reduced. Also provided is a diffraction-type multifocal ophthalmic lens having three or more focal points, which is implemented on the basis of the discovery that the diffraction-type multifocal ophthalmic lens has a characteristic whereby multiple focal points can be generated in the intermediate region as well as the near and far regions. Also provided is a method for manufacturing a diffraction-type multifocal ophthalmic lens which provides a simple design and manufacturing method by means of a simple diffraction structure and by replacing a cumbersome computer simulation with a simple method. This diffraction-type multifocal ophthalmic lens has a diffraction structure (20) where a plurality of diffraction zones are formed concentrically on the lens (10), and an equal-pitch region is provided where pitches of at least two zones among the diffraction zones are made equal.

主权项

1. A diffraction-type multifocal ophthalmic lens having a diffraction structure where a plurality of diffraction zones are formed concentrically on the lens, comprising at least one equal-pitch region where pitches of at least two zones among the diffraction zones are made equal,
wherein the diffraction structure has a Fresnel region composed of a periodic structure with a Fresnel pitch and the equal-pitch region, and the pitch of the Fresnel region is determined by the following equation:⁢rn={2⁢(n-1)+g}×λPadd⁢⁢n⁢:⁢⁢Diffraction⁢⁢zone⁢⁢number⁢⁢of⁢⁢the⁢⁢Fresnel⁢⁢region⁢⁢⁢g=Padd×r12λ⁢⁢⁢λ⁢:⁢⁢Wave⁢⁢length⁢⁢Padd⁢:⁢⁢Addition⁢⁢power⁢⁢in⁢⁢setting⁢⁢a⁢⁢focal⁢⁢point⁢⁢of⁢⁢a⁢⁢first⁢-⁢order⁢⁢diffracted⁢⁢light⁢⁢in⁢⁢the⁢⁢Fresnel⁢⁢region⁢⁢using⁢⁢a⁢⁢focal⁢⁢point⁢⁢position⁢⁢of⁢⁢a⁢⁢0⁢th⁢⁢order⁢⁢diffracted⁢⁢light⁢⁢as⁢⁢a⁢⁢reference⁢⁢rn⁢:⁢⁢Outer⁢⁢radius⁢⁢of⁢⁢an⁢⁢nth⁢⁢diffraction⁢⁢zone⁢⁢of⁢⁢the⁢⁢Fresnel⁢⁢region⁢⁢r1⁢:⁢⁢Outer⁢⁢radius⁢⁢of⁢⁢a⁢⁢1st⁢⁢diffraction⁢⁢zone⁢⁢of⁢⁢the⁢⁢Fresnel⁢⁢region.[Equation⁢⁢1]