US 11,754,815 B2
Imaging lens
Hitoshi Hirano, Tokyo (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. 17/391,815.
Application 17/391,815 is a continuation of application No. 16/894,418, filed on Jun. 5, 2020.
Claims priority of application No. 2019-160510 (JP), filed on Sep. 3, 2019.
Prior Publication US 2021/0356717 A1, Nov. 18, 2021
Int. Cl. G02B 13/00 (2006.01); G02B 27/00 (2006.01); G02B 13/18 (2006.01); G02B 9/64 (2006.01)
CPC G02B 13/0045 (2013.01) [G02B 9/64 (2013.01); G02B 13/18 (2013.01); G02B 27/0025 (2013.01)] 6 Claims
OG exemplary drawing
 
1. An imaging lens forming an image of an object on an image sensor and 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 refractive power,
a fourth lens with negative refractive power,
a fifth lens,
a sixth lens,
a seventh lens with positive refractive power, and
an eighth lens with negative refractive power,
wherein said fourth lens is formed in a shape that curvature radii of an object-side surface and an image-side surface are both negative,
said eighth lens has an aspheric image-side surface having at least one inflection point, and
the following conditional expressions are satisfied:
0.04<D34/f<0.15,
(9′) 1.00<R7r/R7f<=2.08  (9′)
where
f: a focal length of the overall optical system of the imaging lens,
D34: a distance along the optical axis between the third lens and the fourth lens,
R7f: a curvature radius of an object-side surface of the seventh lens, and
R7r: a curvature radius of an image-side surface of the seventh lens.