| 摘要 |
<p>A multifocal lens including annular zones wherein each annular zone is divided into at least two annular sub-zones. Preferably, no geometric or optical steps are present between annular zones or annular sub-zones. The refractive powers within the annular sub-zones are chosen such that the lens exhibits at least two diffractive powers and that at least one of those diffractive powers substantially coincides with the average refractive power of each annular zone.</p> |
