US 11,874,440 B2
Imaging lens
Yukio Sekine, Sukagawa (JP)
Assigned to TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed by TOKYO VISIONARY OPTICS CO., LTD., Tokyo (JP)
Filed on Sep. 30, 2020, as Appl. No. 17/038,122.
Application 17/038,122 is a continuation of application No. 16/156,754, filed on Oct. 10, 2018, granted, now 11,150,445.
Claims priority of application No. 2017-196848 (JP), filed on Oct. 10, 2017.
Prior Publication US 2021/0011262 A1, Jan. 14, 2021
Int. Cl. G02B 13/00 (2006.01); G02B 9/64 (2006.01)
CPC G02B 13/0045 (2013.01) [G02B 9/64 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An imaging lens comprising in order from an object side to an image side,
a first lens having positive refractive power,
a second lens,
a third lens having negative refractive power,
a fourth lens,
a fifth lens having positive refractive power,
a sixth lens, and
a seventh lens, wherein said second lens has a convex surface facing the object side near the optical axis, an image-side surface of said seventh lens is aspheric, and the following conditional expressions (2a) and (16) are satisfied:
−7.1<f2/f<−2.5  (2a)
2.5<|f34|/f<12.0  (16)
where
f: a focal length of the overall optical system,
f2: a focal length of the second lens, and
f34: a composite focal length of the third lens and the fourth lens.