17-03-2016 дата публикации
Номер: US20160077314A1
Принадлежит:
A wide-angle lens system includes a first lens group, an aperture stop, and a second lens group having positive optical power. The first lens group includes, at least, a first lens element that has a meniscus shape convex on the object side, and has negative optical power, a second lens element that has a meniscus shape convex on the object side, and has negative optical power, a third lens element that is concave on the image side and has negative optical power, and a posterior lens element. The second lens element is an aspherical lens, and the second lens element satisfies a conditional expression: 1. A wide-angle lens system comprising , in order from an object side to an image side;a first lens group;an aperture stop; anda second lens group having positive optical power,wherein in order from the object side to the image side, at least,', 'a first lens element that has a meniscus shape convex on the object side, and has negative optical power,', 'a second lens element that has a meniscus shape convex on the object side, and has negative optical power,', 'a third lens element that is concave on the image side and has negative optical power, and', 'a posterior lens element,, 'the first lens group includes'}the second lens element is an aspherical lens, and {'br': None, 'i': R', 'R', 'R', 'R, '0.3<(21−22)/(21+22)<0.8\u2003\u2003(1)'}, 'the second lens element satisfies a conditional expression (1);'} R21 is a radius of paraxial curvature on the object side of the second lens element, and', 'R22 is a radius of paraxial curvature on the image side of the second lens element., 'where'}2. The wide-angle lens system according to claim 1 , whereinthe third lens element is concave on the object side.3. The wide-angle lens system according to claim 1 , wherein {'br': None, '2ω≧180°\u2003\u2003(2)'}, 'the wide-angle lens system satisfies a conditional expression (2)where 2ω is an angle of view.4. The wide-angle lens system according to claim 1 , wherein {'br': None, 'i': ' ...
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