| CPC G02B 13/0045 (2013.01) [G02B 9/64 (2013.01); G02B 27/0025 (2013.01)] | 19 Claims |

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1. An imaging lens system comprising:
a first lens;
a second lens;
a third lens having a concave object-side surface in a paraxial region thereof;
a fourth lens having a concave object-side surface in a paraxial region thereof;
a fifth lens;
a sixth lens having a concave image-side surface in a paraxial region thereof; and
a seventh lens,
wherein the first to seventh lenses are sequentially disposed in ascending numerical order along an optical axis of the imaging lens system from an object side of the imaging lens system toward an imaging plane of the imaging lens system, and
the following conditional expressions are satisfied:
TTL/(2*ImgHT)<0.6
0.4<(R3−R4)/(R3+R4)<0.6
where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, 2*ImgHT is a diagonal length of an effective imaging area of the imaging plane, R3 is a radius of curvature on the optical axis of an object-side surface of the second lens, and R4 is a radius of curvature on the optical axis of an image-side surface of the second lens.
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