发明授权
US5137343A Multifocal surface for a multifocal spectacle lens 失效
多功能镜头的多功能表面

Multifocal surface for a multifocal spectacle lens
摘要:
The invention is directed to a multifocal surface for a multifocal lens which, for a short progression zone between a far-vision zone and near-vision zone, has a large usable width of this zone and the near-vision zone, and for which the maximum value, which the surface astigmatism reaches on the multifocal surface, is less than the 1.1 multiple of the surface increment. Such a multifocal surface is obtained when this surface is configured as twice continuously differentiable and satisfies a combination of six features which relate to the distribution of surface astigmatism and mean surface refractive power across the multifocal surface.
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