IMAGING LENS

摘要

An imaging lens includes a first lens group having positive refractive power and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having negative refractive power, and a third lens. The second lens group includes a front side lens group having negative refractive power and a rear side lens group having positive refractive power. The front side lens group includes a fourth lens and a fifth lens. The rear side lens group includes a sixth lens and a seventh lens. The first lens group is arranged to be away from the second lens group by a specific distance on an optical axis thereof. The first to third lenses have specific Abbe's numbers.

主权项

1. An imaging lens comprising:
a first lens group having positive refractive power; and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side, wherein said first lens group includes a first lens having positive refractive power, a second lens having negative refractive power, and a third lens, said second lens group includes a front side lens group having negative refractive power and a rear side lens group having positive refractive power, said front side lens group includes a fourth lens and a fifth lens, said rear side lens group includes a sixth lens and a seventh lens, and said first lens group is arranged to be away from the second lens group by a distance Da on an optical axis thereof, said first lens has an Abbe's number vd1, said second lens has an Abbe's number vd2, and said third lens has an Abbe's number vd3 so that the following conditional expressions are satisfied:
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