Patent ID: 11867878
Assignee: TOKYO VISIONARY OPTICS CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
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 in a paraxial region,
a third lens with positive refractive power in a paraxial region,
a fourth lens,
a fifth lens with negative refractive power in a paraxial region,
a sixth lens with positive refractive power having an object-side surface being convex in a paraxial region, and
a seventh lens with negative refractive power having an image-side surface being concave in a paraxial region, wherein the following conditional expressions (1), (2a), and (17′) are satisfied:

40.00<νd5<72.00  (1)

4.50≤|r10|/f<40.00  (2a)

1.61<=r5/f<=3.11  (17′)

where
νd5: an abbe number at d-ray of the fifth lens,
r10: a paraxial curvature radius of an image-side surface of the fifth lens,
r5: a paraxial curvature radius of an object-side surface of the third lens, and
f: a focal length of the overall optical system of the imaging lens.