Image lens assembly system
An image lens assembly system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first lens element with negative refractive power has a convex object-side surface. The second lens element has positive refractive power. The third lens element has refractive power. The fourth lens element has refractive power. The fifth lens element has refractive power. The sixth lens element with refractive power is made of plastic material, wherein at least one surface of the sixth lens element is aspheric. The seventh lens element with refractive power made of plastic material has a concave image-side surface changing from concave in a paraxial region to convex in a peripheral region, and at least one surface thereof is aspheric.
1. An image lens assembly system comprising, in order from an object side to an image side:
a first lens element having refractive power;
a second lens element having positive refractive power;
a third lens element having refractive power;
a fourth lens element having refractive power;
a fifth lens element having refractive power;
a sixth lens element with refractive power made of plastic material, wherein at least one of an object-side surface and an image-side surface of the sixth lens element is aspheric; and
a seventh lens element with refractive power made of plastic material and having a concave image-side surface, wherein the image-side surface of the seventh lens element changes from concave in a paraxial region thereof to convex in a peripheral region thereof, and at least one of an object-side surface and the image-side surface thereof is aspheric;
wherein the image lens assembly system has a total of seven lens elements with refractive power, there is an air gap between two adjacent surfaces of any two adjacent lens elements of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element, a focal length of the image lens assembly system is f, a composite focal length of the first lens element and the second lens element is f12, and the following relationship is satisfied:
0.1 <f/f 12<1.8.
2. The image lens assembly system of claim 1 , wherein the second lens element has a convex object-side surface.
3. The image lens assembly system of claim 1 , wherein the fifth lens element has a convex image-side surface.
4. The image lens assembly system of claim 1 , wherein the object-side surface of the seventh lens element is convex.
5. The image lens assembly system of claim wherein the fourth lens element has positive refractive power.
6. The image lens assembly system of claim 1 , wherein a curvature radius of the object-side surface of the seventh lens element is R13, a curvature radius of the image-side surface of the seventh lens element is R14, and the following relationship is satisfied:
0 <R 14 /|R 13|<0.5.
7. The image lens assembly system of claim 1 , wherein a curvature radius of an object-side surface of the fifth lens element is R9, a curvature radius of an image-side surface of the fifth lens element is R10, and the following relationship is satisfied:
|( R 9 −R 10)/( R 9 +R 10)|<0.35.
8. The image lens assembly system of claim 1 , wherein a sum of central thicknesses from the first through seventh lens elements is ΣCT, an axial distance between an object-side surface of the first lens element and the image-side surface of the seventh lens element is Td, and the following relationship is satisfied:
0.60<ΣCT/ Td< 0.90.
9. The image lens assembly system of claim 1 , wherein an axial distance between an object-side surface of the first lens element and an image plane is TTL, a maximum image height of the image lens assembly system is ImgH, and the following relationship is satisfied:
TTL /ImgH<1.85.
10. The image lens assembly system of claim 1 , wherein a sum of central thicknesses from the first through seventh lens elements is ΣCT, an axial distance between an object-side surface of the first lens element and the image-side surface of the seventh lens element is Td, and the following relationship is satisfied:
0.70≦ΣCT/ Td< 0.90.
11. The image lens assembly system of claim 1 , wherein at least one of the third lens element and the fourth lens element has at least one surface changing from concave to convex or changing from convex to concave from a paraxial region thereof to a peripheral region thereof.
12. The image lens assembly system of claim 1 , further comprising:
a stop disposed between an object and the second lens element.
13. An imaging device, comprising:
the mage lens assembly system of claim 1 ; and
an image sensor located on an image plane of the image lens assembly system.
14. An image lens assembly system comprising, in order from an object side to an image side:
a first lens element having refractive power;
a second lens element having positive refractive power;
a third lens element having refractive power;
a fourth lens element having refractive power;
a fifth lens element having refractive power;
a sixth lens element with refractive power made of plastic material, wherein at least one of an object-side surface and an image-side surface of the sixth lens element is aspheric; and
a seventh lens element with refractive power made of plastic material and having a concave image-side surface, wherein the image-side surface of the seventh lens element changes from concave in a paraxial region thereof to convex in a peripheral region thereof, and at least one of an object-side surface and the image-side surface thereof is aspheric;
wherein the image lens assembly system has a total of seven lens elements with refractive power, there is an air gap between two adjacent surfaces of any two adjacent lens elements of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element, an axial distance between an object-side surface of the first lens element and the image-side surface of the seventh lens element is Td, and the following relationship is satisfied:
3.2 mm< Td< 7.0 mm.
15. The image lens assembly system of claim 4 , wherein the first lens element has a convex object-side surface.
16. The image lens assembly system of claim 14 , wherein the image-side surface of the sixth lens element is convex.
17. The image lens assembly system of claim 14 , wherein the sixth lens element has positive refractive power.
18. The image lens assembly system of claim 14 , wherein the third lens element has negative refractive power.
19. The image lens assembly system of claim 14 , wherein a focal length of the image lens assembly system is f, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, and the following relationship is satisfied:
1.4< f/f 2+ f/f 4<2.6.
20. The image lens assembly system of claim 14 , wherein a focal length of the image lens assembly system is f, a focal length of the seventh lens element is f7, and the following relationship is satisfied:
−0.70< f 7/ f<− 0.30.
21. The image lens assembly system of claim 14 , wherein a curvature radius of the object-side surface of the seventh lens element is R13, a curvature radius of the image-side surface of the seventh lens element is R14, and the following relationship is satisfied:
0 <R 14/| R 13|<0.5.
22. The image lens assembly system of claim 14 , wherein a focal length of the image lens assembly system is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, and the following relationships are satisfied:
| f/f 2 |>f/f 1 , |f/f 2 |>f/f 3 , |f/f 2| >f/f 4, and | f/f 2 |>f/f 5.
23. The image lens assembly system of claim 14 , wherein at least one of the third lens element and the fourth lens element has at least one surface changing from concave to convex or changing from convex to concave from a paraxial region thereof to a peripheral region thereof.
24. The image lens assembly system of claim 14 , wherein an axial distance between the object-side surface of the first lens element and an image plane is TTL, a maximum image height of the image lens assembly system is ImgH, and the following relationship is satisfied:
TTL /Img H< 1.85.
25. An imaging device, comprising:
the image lens assembly system of claim 14 ; and
an image sensor located on an image plane of the image lens assembly system.