US 11,740,433 B2
Imaging lens
Yoji Kubota, Nagano (JP); Kenichi Kubota, Tokyo (JP); Hitoshi Hirano, Tokyo (JP); and Hisao Fukaya, Tokyo (JP)
Assigned to TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed by TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed on Jun. 1, 2020, as Appl. No. 16/888,900.
Application 16/888,900 is a division of application No. 16/251,153, filed on Jan. 18, 2019, granted, now 10,996,443.
Application 16/251,153 is a continuation of application No. 15/479,385, filed on Apr. 5, 2017, granted, now 10,241,302, issued on Mar. 26, 2019.
Claims priority of application No. 2016-096676 (JP), filed on May 13, 2016.
Prior Publication US 2020/0292793 A1, Sep. 17, 2020
Int. Cl. G02B 9/62 (2006.01); G02B 13/00 (2006.01)
CPC G02B 9/62 (2013.01) [G02B 13/0045 (2013.01)] 6 Claims
OG exemplary drawing
 
1. An imaging lens comprising:
a first lens having positive refractive power;
a second lens;
a third lens;
a fourth lens;
a fifth lens; and
a sixth lens, arranged in this order from an object side to an image plane side, with spaces present between adjacent pairs of the first through sixth of the lenses,
wherein said imaging lens has only six lenses with refractive power,
said first lens is formed in a shape so that at least one surface thereof is aspheric,
said third lens is formed in a shape so that at least one surface thereof is aspheric,
said fourth lens is formed in a shape so that at least one surface thereof is aspheric,
said fifth lens is formed in a shape so that two surfaces thereof are aspheric and the surface thereof on the object side is convex toward the object side near an optical axis thereof,
said sixth lens is formed in a shape so that two surfaces thereof are aspheric and the surface thereof on the image plane side is convex toward the image plane side near an optical axis thereof, and said second lens has a focal length f2, said third lens has a focal length f3, said second lens has an Abbe's number vd2, and said fifth lens has an Abbe's number vd5 so that the following conditional expressions are satisfied:
0.2<|f3/f2|<1.2,
35<vd2<75,
35<vd5<75.