发明名称 WIDE-ANGLE LENS SYSTEM
摘要 A retro-focus wide-angle lens system having, in order from the object side, a negative power front group and a positive power rear group having a diaphragm stop. The front group comprises a positive first lens element and a negative meniscus second lens element having a convex surface directed towards the object. The rear group comprises a positive third lens element, a negative fourth lens element having an aspheric surface and a positive fifth lens element. The negative power of the fourth lens element increases toward the outer edge.
申请公布号 US5233474(A) 申请公布日期 1993.08.03
申请号 US19920830377 申请日期 1992.01.31
申请人 ASAHI KOGAKU KOGYO K.K. 发明人 HIRAKAWA, JUN
分类号 G02B13/04;G02B13/18 主分类号 G02B13/04
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