Imaging lens system
An imaging lens system includes a first lens; a second lens; a third lens having a concave object-side surface in a paraxial region thereof; a fourth lens; a fifth lens; a sixth lens; 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 conditional expression TTL/(2*ImgHT)<0.6 is satisfied, where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, and 2*ImgHT is a diagonal length of an effective imaging area of the imaging plane.
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<( R 3− R 4)/( R 3+ R 4)<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.
2. The imaging lens system of claim 1 , wherein a field of view of the imaging lens system is 84 degrees or more.
3. The imaging lens system of claim 1 , wherein an f-number of the imaging lens system is less than 1.9.
4. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
0.7 <TTL/f <1.2
where f is a focal length of the imaging lens system.
5. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
0.1< D 34/ D 67<0.3
where D34 is a distance along the optical axis from an image-side surface of the third lens to the object-side surface of the fourth lens, and D67 is a distance along the optical axis from the image-side surface of the sixth lens to an object-side surface of the seventh lens.
6. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
0.4< R 1/ R 11<0.8
where R1 is a radius of curvature on the optical axis of the object-side surface of the first lens, and R11 is a radius of curvature on the optical axis of an object-side surface of the sixth lens.
7. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
−0.8<( R 11− R 12)/( R 11+ R 12)<−0.1
where R11 is a radius of curvature on the optical axis of an object-side surface of the sixth lens, and R12 is a radius of curvature on the optical axis of the image-side surface of the sixth lens.
8. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
0.1<( R 12* D 56)/( f *ImgHT)<0.3
where R12 is a radius of curvature on the optical axis of the image-side surface of the sixth lens, D56 is a distance along the optical axis from an image-side surface of the fifth lens to an object-side surface of the sixth lens, f is a focal length of the imaging lens system, and ImgHT is a maximum effective image height on the imaging plane.
9. The imaging lens system of claim 1 , wherein the following conditional expression is satisfied:
1.0<( V 4+ V 5)/ V 3<2.0
where V3 is an Abbe number of the third lens, V4 is an Abbe number of the fourth lens, and V5 is an Abbe number of the fifth lens.
10. An imaging lens system comprising:
a first lens having a refractive power;
a second lens having a refractive power;
a third lens having a positive refractive power, and a concave object-side surface in a paraxial region thereof;
a fourth lens having a refractive power;
a fifth lens having a refractive power;
a sixth lens having a refractive power; and
a seventh lens having a convex object-side surface in a paraxial region thereof,
wherein the first lens to the seventh lens are sequentially disposed spaced apart from each other 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:
0.7< TTL/f< 1.2
0.4<( R 3− R 4)/( R 3+ R 4)<0.6
where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane, f is a focal length of the imaging lens system, 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.
11. The imaging lens system of claim 10 , wherein the third lens has a convex image-side surface in a paraxial region thereof.
12. The imaging lens system of claim 10 , wherein the fourth lens has a concave object-side surface in a paraxial region thereof.
13. The imaging lens system of claim 10 , wherein the fourth lens has a concave image-side surface in a paraxial region thereof.
14. The imaging lens system of claim 10 , wherein the fourth lens has a negative refractive power.
15. The imaging lens system of claim 10 , wherein the sixth lens has a concave image-side surface in a paraxial region thereof.
16. An imaging lens system comprising:
a first lens;
a second lens;
a third lens;
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 having a convex object-side surface in a paraxial region thereof,
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<( R 3− R 4)/( R 3+ R 4)<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.
17. The imaging lens system of claim 16 , wherein a field of view of the imaging lens system is 84 degrees or more.
18. The imaging lens system of claim 16 , wherein an f-number of the imaging lens system is less than 1.9.
19. The imaging lens system of claim 16 , wherein the following conditional expression is satisfied:
0.7< TTL/f< 1.2
where f is a focal length of the imaging lens system.