发明名称 Zonal bifocal contact lens
摘要 A multifocal lens design suitable for use as an opthalmic contact lens. A zonal bifocal contact lens utilizes the multifocal Fresnel lens designs which have their multifocal property distributed approximately throughout the lens. This is accomplished by a lens construction in which the optical facets are interfaced without any non-refractive ledges or steps occurring between adjacent facets.
申请公布号 US4162122(A) 申请公布日期 1979.07.24
申请号 US19770833368 申请日期 1977.09.14
申请人 COHEN, ALLEN L 发明人 COHEN, ALLEN L
分类号 G02B5/18;(IPC1-7):G02B3/08;G02B3/10;G02C7/04 主分类号 G02B5/18
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