| 摘要 |
<p>This invention discloses a multi-focal lens equipped with small progressive-focal lenses. A base lens (1) is used for a distance mono-focal zone (F). A reading mono-focal zone (N) and a progressive-focal zone (P), or an intermediate mono-focal zone (I), the progressive-focal zone (P) and the reading mono-focal zone (N) are disposed only on a small lens (2) providing entry refracting power by means of the surface refracting power. The base lens and the small lens are embedded integrally and projectingly. Alternatively, a small lens having a different refraction index is buried into the base lens or still alternatively, a small lens produced separately is fixed to the surface of the base lens, in order to expand the normal vision range, to eliminate those portions which have high aberration resulting from progressive graduation and to obtain a progressive-focal small lens of free design. Furthermore, small prism lenses are systematically grouped for selective use in accordance with prescription.</p> |
