US 12,124,005 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 Nov. 16, 2020, as Appl. No. 17/099,323.
Application 17/099,323 is a continuation of application No. 16/784,657, filed on Feb. 7, 2020, abandoned.
Claims priority of application No. 2019-021588 (JP), filed on Feb. 8, 2019.
Prior Publication US 2021/0389572 A1, Dec. 16, 2021
Int. Cl. G02B 13/18 (2006.01); G02B 9/60 (2006.01); G02B 13/00 (2006.01); G02B 27/00 (2006.01)
CPC G02B 13/0045 (2013.01) [G02B 9/60 (2013.01); G02B 27/0025 (2013.01)] 9 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 having an object-side surface being convex in a paraxial region,
a second lens with negative refractive power having an object-side surface being convex in a paraxial region,
a third lens with positive or negative refractive power in a paraxial region,
a fourth lens with negative refractive power in a paraxial region, and
a fifth lens with positive refractive power having an image-side surface being convex in a paraxial region,
wherein said third lens has an object-side surface being convex in the paraxial region, and following conditional expressions (1), (2), (3), and (6) are satisfied:
45.00<νd4<68.00  (1)
0.30<r2/r8<2.00  (2)
3.00<(T2/f)×100<14.00  (3)
4.50<r5/D3<31.00  (6)
where
νd4: an Abbe number at d-ray of the fourth lens,
r2: a paraxial curvature radius of an image-side surface of the first lens,
r8: a paraxial curvature radius of an image-side surface of the fourth lens,
T2: a distance along an optical axis from an image-side surface of the second lens to the object-side surface of the third lens,
f: a focal length of the overall optical system of the imaging lens,
r5: a paraxial curvature radius of the object-side surface of the third lens, and
D3: a thickness along the optical axis of the third lens.