| 摘要 |
A both-plane aspherical progressive refractive power lens group reduced in processing costs. The same first refractive surface is employed for at least two kinds of different additional powers in a both-plane aspherical progressive refractive power lens, where, when a lateral surface refractive power and a longitudinal surface refractive power at a distance power measuring point F1 on the first refractive surface as an object-side surface are respectively DHf and DVf and a lateral surface refractive power and a longitudinal surface refractive power at a reading power measuring point N1 on this first refractive surface are respectively DHn and DVn, the relational expressions DHf + DHn ADD/2 and DHn-DHf < ADD/2 are further satisfied and at the same time surface astigmatic components at F1 and N1 on the first refractive surface are offset on a second refractive surface as an eyeball-side surface to give a distance power (Df) and an additional power (ADD) based on a prescription value in combination of the first and the second refractive surfaces. ® KIPO & WIPO 2008
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