US 11,808,924 B2
Imaging lens
Shingo Yuza, Sukagawa (JP); and Kenichi Kamada, Sukagawa (JP)
Assigned to TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed by TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed on Aug. 2, 2021, as Appl. No. 17/391,734.
Application 17/391,734 is a continuation of application No. 16/831,154, filed on Mar. 26, 2020, granted, now 11,609,407.
Claims priority of application No. 2019-059619 (JP), filed on Mar. 27, 2019.
Prior Publication US 2021/0356715 A1, Nov. 18, 2021
Int. Cl. G02B 9/60 (2006.01); G02B 13/00 (2006.01); H04N 23/54 (2023.01)
CPC G02B 13/0045 (2013.01) [G02B 9/60 (2013.01); H04N 23/54 (2023.01)] 5 Claims
OG exemplary drawing
 
1. An imaging lens comprising in order from an object side to an image side,
a first lens with positive refractive power formed in a biconvex shape having an object-side surface and an image-side surface being convex in a paraxial region,
a second lens with negative refractive power in a paraxial region,
a third lens with the negative refractive power in a paraxial region,
a fourth lens with the negative refractive power in a paraxial region, and
a fifth lens with the positive refractive power having an image-side surface being convex in a paraxial region,
wherein an image-side surface of said third lens is concave in the paraxial region, and the following conditional expressions (1), (2) and (4) are satisfied:
10.00<νd2<30.00  (1)
0.10<|r5|/f<0.90  (2)
2.00<r8/f<35.00  (4)
where
νd2: an abbe number at d-ray of the second lens,
r5: a paraxial curvature radius of an object-side surface of the third lens,
r8: a paraxial curvature radius of an image-side surface of the fourth lens, and
f: a focal length of the overall optical system of the imaging lens.