23-01-2020 дата публикации
Номер: US20200026047A1
Принадлежит:
An imaging lens of the disclosure includes, in order from an object side toward an image plane side, a first lens group having positive refractive power and including a plurality of optical elements, a second lens group having positive refractive power, and a third lens group having negative refractive power. The second lens group travels in an optical axis direction upon focusing. The plurality of optical elements include, in order from the object side toward the image plane side, at least a first lens having positive refractive power and a second lens, and predetermined conditional expressions are satisfied. 1. An imaging lens comprising , in order from an object side toward an image plane side:a first lens group having positive refractive power and including a plurality of optical elements;a second lens group having positive refractive power; anda third lens group having negative refractive power,the second lens group traveling in an optical axis direction upon focusing,the plurality of optical elements including, in order from the object side toward the image plane side, at least a first lens having positive refractive power and a second lens, [{'br': None, 'i': DL', 'R, '0.20<12/0.5\u2003\u2003(1)'}, {'br': None, 'i': 'd', 'νmin>15\u2003\u2003(2)'}], 'wherein the following conditional expressions are satisfiedwhereDL12 is an air space between the first lens and the second lens,f is a focal distance, in a d-line, of entire system upon infinity focusing, andνdmin is a minimum value of Abbe numbers of the respective plurality of optical elements.2. The imaging lens according to claim 1 , wherein the following conditional expression is further satisfied:{'br': None, 'i': ndL', '×νdL', '×νdL', '×νdL, 'sup': −6', '3', '−4', '2', '−2, '1.53<11<−1.036×1011+2.481×1011−1.996×1011+2.169.\u2003\u2003 (3)'}wherendL11 is a refractive index, in a d-line, of the first lens, andνdL11 is Abbe number of the first lens.3. The imaging lens according to claim 1 , wherein the ...
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