Optical imaging lens

1. An optical imaging lens comprising sequentially from an object side to an image side along an optical axis: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element, each of the first, second, third, fourth, fifth and sixth 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 positive refracting power;

the object-side surface of the second lens element or the image-side surface of the second lens element is an aspherical surface;

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

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

the fifth lens element has negative refracting power;

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

a focal length of the first lens element is represented by f1, a focal length of the second lens element is represented by f2, a distance between the object-side surface of the first lens element and an image plane along the optical axis is represented by TTL, an effective focal length of the optical imaging lens is represented by EFL, and the optical imaging lens satisfies inequalities:

1.5×| f 1|>| f 2|;

f 1> TTL/ 2;

EFL/TTL≥ 1.000; and

TTL ≤15 mm.

2. The optical imaging lens according to claim 1 , wherein an Abbe number of the first lens element is represented by v1, an Abbe number of the second lens element is represented by v2, an Abbe number of the fourth lens element is represented by v4, and

wherein the optical imaging lens further satisfies an inequality: v1>v2+v4.

3. The optical imaging lens according to claim 1 , wherein a central thickness of the first lens element along the optical axis is represented by T1, a central thickness of the second lens element along the optical axis is represented by T2, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and wherein the optical imaging lens further satisfies an inequality: (T1+T2+G34+G56)/G45≤8.000.

4. The optical imaging lens according to claim 1 , wherein a central thickness of the second lens element along the optical axis is represented by T2, a central thickness of the fifth lens element along the optical axis is represented by T5, a central thickness of the sixth lens element along the optical axis is represented by T6, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, and an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T2+G34+T5+G56+T6)/G45≤6.000.

5. The optical imaging lens according to claim 1 , wherein a sum of central thicknesses from the first to the sixth lens elements along the optical axis is represented by ALT, a central thickness of the first lens element along the optical axis is represented by T1, an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, and

wherein the optical imaging lens further satisfies an inequality: ALT/(T1+G12+G23)≤5.000.

6. The optical imaging lens according to claim 1 , wherein an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, and

wherein the optical imaging lens further satisfies an inequality: G34/(G12+G23)≤4.500.

7. The optical imaging lens according to claim 1 , wherein an effective focal length of the optical imaging lens is represented by EFL, a central thickness of the first lens element along the optical axis is represented by T1, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, and

wherein the optical imaging lens further satisfies an inequality: EFL/(T1+G45)≤6.000.

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

the first lens element has positive refracting power;

the object-side surface of the second lens element or the image-side surface of the second lens element is an aspherical surface;

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

the fifth lens element has negative refracting power;

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

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

a focal length of the first lens element is represented by f1, a focal length of the second lens element is represented by f2, a distance between the object-side surface of the first lens element and an image plane along the optical axis is represented by TTL, an effective focal length of the optical imaging lens is represented by EFL, and the optical imaging lens satisfies inequalities:

1.5×| f 1|>| f 2|;

f 1> TTL/ 2;

EFL/TTL≥ 1.000; and

TTL ≤15 mm.

9. The optical imaging lens according to claim 8 , wherein an Abbe number of the first lens element is represented by v1, an Abbe number of the second lens element is represented by v2, an Abbe number of the sixth lens element is represented by v6, and

wherein the optical imaging lens further satisfies an inequality: v1>v2+v6.

10. The optical imaging lens according to claim 8 , wherein a central thickness of the first lens element along the optical axis is represented by T1, a central thickness of the third lens element along the optical axis is represented by T3, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T1+T3+G34+G56)/G45≤7.800.

11. The optical imaging lens according to claim 8 , wherein a central thickness of the third lens element along the optical axis is represented by T3, a central thickness of the fifth lens element along the optical axis is represented by T5, a central thickness of the sixth lens element along the optical axis is represented by T6, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T3+G34+T5+G56+T6)/G45≤6.600.

12. The optical imaging lens according to claim 8 , wherein a sum of air gaps from the first to the sixth lens elements along the optical axis is represented by AAG, a central thickness of the first lens element along the optical axis is represented by T1, an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, and

wherein the optical imaging lens further satisfies an inequality: AAG/(T1+G12+G23)≤4.500.

13. The optical imaging lens according to claim 8 , wherein a central thickness of the fifth lens element along the optical axis is represented by T5, an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T5+G56)/(G12+G23)≤8.000.

14. The optical imaging lens according to claim 8 , wherein a distance from the object-side surface of the first lens element to the image-side surface of the sixth lens element along the optical axis is represented by TL, a central thickness of the first lens element along the optical axis is represented by T1, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, and

wherein the optical imaging lens further satisfies an inequality: TL/(T1+G45)≤5.000.

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

the first lens element has positive refracting power;

the object-side surface of the second lens element or the image-side surface of the second lens element is an aspherical surface;

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

the fifth lens element has negative refracting power;

the image-side surface of the fifth lens element comprises a convex portion in a vicinity of a periphery of the fifth lens element;

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

a focal length of the first lens element is represented by f1, a focal length of the second lens element is represented by f2, a distance between the object-side surface of the first lens element and an image plane along the optical axis is represented by TTL, an effective focal length of the optical imaging lens is represented by EFL, and the optical imaging lens satisfies inequalities:

1.5×| f 1|>| f 2|;

f 1> TTL/ 2;

EFL/TTL≥ 1.000; and

TTL ≤9 mm.

16. The optical imaging lens according to claim 15 , wherein an Abbe number of the first lens element is represented by v1, an Abbe number of the fourth lens element is represented by v4, an Abbe number of the sixth lens element is represented by v6, and

wherein the optical imaging lens further satisfies an inequality: v1>v4+v6.

17. The optical imaging lens according to claim 15 , wherein a central thickness of the first lens element along the optical axis is represented by T1, a central thickness of the fourth lens element along the optical axis is represented by T4, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T1+T4+G34+G56)/G45≤8.000.

18. The optical imaging lens according to claim 15 , wherein a central thickness of the fourth lens element along the optical axis is represented by T4, a central thickness of the fifth lens element along the optical axis is represented by T5, a central thickness of the sixth lens element along the optical axis is represented by T6, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, an air gap between the fourth lens element and the fifth lens element along the optical axis is represented by G45, an air gap between the fifth lens element and the sixth lens element along the optical axis is represented by G56, and

wherein the optical imaging lens further satisfies an inequality: (T4+G34+T5+G56+T6)/G45≤6.300.

19. The optical imaging lens according to claim 15 , wherein a distance from the image-side surface of the sixth lens element to an image plane along the optical axis is represented by BFL, an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, and

wherein the optical imaging lens further satisfies an inequality: BFL/(G12+G23)≤5.500.

20. The optical imaging lens according to claim 15 , wherein a central thickness of the sixth lens element along the optical axis is represented by T6, an air gap between the first lens element and the second lens element along the optical axis is represented by G12, an air gap between the second lens element and the third lens element along the optical axis is represented by G23, and

wherein the optical imaging lens further satisfies an inequality: T6/(G12+G23)≤3.000.