US 11,988,820 B2
Imaging lens
Yukio Sekine, Tokyo (JP); Koki Tokuno, Tokyo (JP); and Zhiyu Huang, Tokyo (JP)
Assigned to TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed by TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed on Apr. 28, 2021, as Appl. No. 17/242,899.
Claims priority of application No. 2020-078764 (JP), filed on Apr. 28, 2020.
Prior Publication US 2022/0155567 A1, May 19, 2022
Int. Cl. G02B 13/18 (2006.01); G02B 9/62 (2006.01)
CPC G02B 13/18 (2013.01) [G02B 9/62 (2013.01)] 6 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,
a second lens with negative refractive power,
a third lens with positive or negative refractive power,
a fourth lens with negative refractive power,
a fifth lens with positive refractive power, and
a sixth lens with negative refractive power,
wherein said first lens is formed in a meniscus shape having an object-side surface being convex in a paraxial region, said second lens has an object-side surface being convex in a paraxial region, said sixth lens has an image-side surface being concave in a paraxial region, and the following conditional expressions (1), (2), (3), and (7) are satisfied:
f4/f←13.00  (1)
0.10<(r6/|f3|)×100<55.00  (2)
7.50<r7/T3<20.00  (3)
|r9|/r10←8.40  (7)
where
f4: a focal length of the fourth lens,
f: a focal length of the overall optical system of the imaging lens,
r6: a paraxial curvature radius of an image-side surface of the third lens,
f3: a focal length of the third lens,
r7: a paraxial curvature radius of an object-side surface of the fourth lens, and
T3: a distance along an optical axis from an image-side surface of the third lens to an object-side surface of the fourth lens,
r9: a paraxial curvature radius of an object-side surface of the fifth lens, and
r10: a paraxial curvature radius of an image-side surface of the fifth lens.