Patent ID: 11914112
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 having a convex surface facing the object side near an optical axis and positive refractive power,
a second lens,
a third lens,
a fourth lens,
a fifth lens having a meniscus shape near the optical axis,
a sixth lens, and
a seventh lens having a concave surface facing the image side near the optical axis and negative refractive power, wherein
an image-side surface of said seventh lens is formed as an aspheric surface having at least one pole point in a position off the optical axis,
the first lens having a meniscus shape near the optical axis,
an image-side surface of said fourth lens has a concave surface facing the image side near the optical axis,
said fifth lens has positive refractive power near the optical axis,
an object-side surface of said seventh lens has a convex surface facing the object side near the optical axis, and
below conditional expressions (1), (2) and (13) are satisfied:

1.50<(D1/f1)×100<17.00  (1)

0.02<T2/T4<0.10  (2)

0.70<r13/f<6.50  (13)

where
D1: a thickness along the optical axis of the first lens,
f1: a focal length of the first lens,
T2: a distance along the optical axis from an image-side surface of the second lens to an object-side surface of the third lens,
T4: a distance along the optical axis from an image-side surface of the fourth lens to an object-side surface of the fifth lens,
r13: paraxial curvature radius of an object-side surface of the seventh lens, and
f: the focal length of the overall optical system of the imaging lens.