Imaging lens and electronic apparatus having the same

1. An optical imaging lens comprising, sequentially from an object side to an image side along an optical axis, first, second, third, fourth and fifth lens elements, each of the first, second, third, fourth and fifth lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein:

the first lens element has a positive refractive power and the object-side surface of the first lens element comprises a convex portion in a vicinity of its periphery;

the image-side surface of the second lens element comprises a concave portion in a vicinity of the optical axis;

the object-side surface of the third lens element comprises a concave portion in a vicinity of its periphery;

the image-side surface of the fourth lens element comprises a convex portion in a vicinity of the optical axis;

the image-side surface of the fifth lens element comprises a concave portion in a vicinity of the optical axis and the object-side surface of the fifth lens element comprises a convex portion in a vicinity of its periphery; and

for the optical imaging lens as a whole, only the five lens elements have refractive power.

2. The optical imaging lens according to claim 1 wherein a sum of thicknesses of all five lens elements along the optical axis is ALT, an air gap between the first lens element and the second lens element along the optical axis is G12, an air gap between the second lens element and the third lens element along the optical axis is G23, and ALT, G12 and G23 satisfy the relation:

4.7≦ ALT /( G 12+ G 23)<5.9.

3. The optical imaging lens according to claim 2 wherein a central thickness of the fourth lens element along the optical axis is T4, a central thickness of the third lens element along the optical axis is T3, and T4 and T3 satisfy the relation:

1.5≦ T 4/ T 3≦2.0.

4. The optical imaging lens according to claim 3 wherein an aperture stop is disposed at the object-side of the first lens.

5. The optical imaging lens according to claim 1 wherein an effective system focal length is EFL, an air gap between the fourth lens element and the fifth lens element along the optical axis is G45, a central thickness of the fifth lens element along the optical axis is T5, and EFL, G45 and T5 satisfy the relation:

4.7≦ EFL /( G 45+ T 5)≦6.3.

6. The optical imaging lens according to claim 5 wherein a central thickness of the first lens element along the optical axis is T1, a central thickness of the second lens element along the optical axis is T2, a central thickness of the third lens element along the optical axis is T3, and T1, T2 and T3 satisfy the relation:

2.1≦( T 1+ T 2)/ T 3≦2.8.

7. The optical imaging lens according to claim 1 wherein a sum of all four air gaps from the first lens element to the fifth lens element along the optical axis is G all-air , an air gap between the first lens element and the second lens element along the optical axis is G12, an air gap between the fourth lens element and the fifth lens element along the optical axis is G45, and G all-air , G12 and G45 satisfy the relation:

2.3< G all-air /( G 12+ G 45)≦3.8.

8. The optical imaging lens according to claim 7 wherein a sum of thicknesses of all five lens elements along the optical axis is ALT, a central thickness of the third lens element along the optical axis is T3, an air gap between the third lens element and the fourth lens element along the optical axis is G34, and ALT, T3 and G34 satisfy the relation:

3.6≦ ALT /( T 3+ G 34)≦4.6.

9. The optical imaging lens according to claim 1 wherein a central thickness of the fourth lens element along the optical axis is T4, a central thickness of the fifth lens element along the optical axis is T5, an air gap between the second lens element and the third lens element along the optical axis is G23, and T4, T5 and G23 satisfy the relation:

2.6≦( T 4+ T 5)/ G 23≦3.2.

10. The optical imaging lens according to claim 9 wherein an effective system focal length is EFL, a central thickness of the first lens element along the optical axis is T1, an air gap between the first lens element and the second lens element along the optical axis is G12, and EFL, T1 and G12 satisfy the relation:

5.7≦ EFL /( T 1+ G 12)≦6.3.

11. The optical imaging lens according to claim 10 wherein the object-side surface of the fifth lens element comprises a convex portion in a vicinity of the optical axis.

12. The optical imaging lens according to claim 1 wherein a central thickness of the first lens element along the optical axis is T1, a central thickness of the second lens element along the optical axis is T2, a central thickness of the third lens element along the optical axis is T3, and T1, T2 and T3 satisfy the relation:

2.4≦ T 1/ T 2+ T 2/ T 3≦3.1.

13. The optical imaging lens according to claim 12 wherein a central thickness of the fourth lens element along the optical axis is T4, a central thickness of the fifth lens element along the optical axis is T5, and T3, T4 and T5 satisfy the relation:

1.7≦ T 3/ T 4+ T 4/ T 5≦2.3.

14. The optical imaging lens according to claim 1 wherein a sum of all four air gaps from the first lens element to the fifth lens element along the optical axis is G all-air , a central thickness of the first lens element along the optical axis is T1, and G all-air and T1 satisfy the relation:

1.4≦ G all-air /T 1≦1.8.

15. The optical imaging lens according to claim 14 wherein a sum of the thickness of all five lens elements along the optical axis is ALT, an air gap between the second lens element and the third lens element along the optical axis is G23, an air gap between the third lens element and the fourth lens element along the optical axis is G34, and ALT, G23 and G34 satisfy the relation:

3.4≦ ALT /( G 23+ G 34)≦4.2.

16. The optical imaging lens according to claim 15 wherein the fourth lens element has a positive refractive power.