1. An optical imaging lens, comprising a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially arranged along an optical axis from an object side to an image side, wherein each of the first lens element to the eighth lens element comprises an object-side surface facing the object side and allowing imaging rays to pass through and an image-side surface facing the image side and allowing the imaging rays to pass through; the second lens element has negative refracting power; the third lens element has positive refracting power, and a periphery region of the image-side surface of the third lens element is concave; an optical axis region of the object-side surface of the fourth lens element is concave; and an optical axis region of the image-side surface of the seventh lens element is convex, wherein lens elements of the optical imaging lens are only the eight lens elements, and satisfy conditions as follows: | V 4− V 5|≥30.000; and (G67+T7)/(G56+T6)≥1.500, wherein V4 is an Abbe number of the fourth lens element; V5 is an Abbe number of the fifth lens element; G67 is an air gap between the sixth lens element and the seventh lens element on the optical axis; T7 is a thickness of the seventh lens element on the optical axis; G56 is an air gap between the fifth lens element and the sixth lens element on the optical axis; and T6 is a thickness of the sixth lens element on the optical axis, wherein the air gap between the fifth lens element and the sixth lens element on the optical axis is less than the air gap between the sixth lens element and the seventh lens element on the optical axis.
2. An optical imaging lens, comprising a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially arranged along an optical axis from an object side to an image side, wherein each of the first lens element to the eighth lens element comprises an object-side surface facing the object side and allowing imaging rays to pass through and an image-side surface facing the image side and allowing the imaging rays to pass through; the second lens element has negative refracting power; the third lens element has positive refracting power, and a periphery region of the image-side surface of the third lens element is concave; an optical axis region of the object-side surface of the fourth lens element is concave; the fifth lens element has negative refracting power; the sixth lens element has negative refracting power; and an optical axis region of the image-side surface of the seventh lens element is convex, wherein lens elements of the optical imaging lens are only the eight lens elements, and satisfy conditions as follows: | V 4− V 5|≥30.000; and (G67+T7)/(G56+T6)≥1.500, wherein V4 is an Abbe number of the fourth lens element; V5 is an Abbe number of the fifth lens element; G67 is an air gap between the sixth lens element and the seventh lens element on the optical axis; T7 is a thickness of the seventh lens element on the optical axis; G56 is an air gap between the fifth lens element and the sixth lens element on the optical axis; and T6 is a thickness of the sixth lens element on the optical axis, wherein the air gap between the fifth lens element and the sixth lens element on the optical axis is less than the air gap between the sixth lens element and the seventh lens element on the optical axis.
3. An optical imaging lens, comprising a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially arranged along an optical axis from an object side to an image side, wherein each of the first lens element to the eighth lens element comprises an object-side surface facing the object side and allowing imaging rays to pass through and an image-side surface facing the image side and allowing the imaging rays to pass through; the second lens element has negative refracting power; the third lens element has positive refracting power, and a periphery region of the image-side surface of the third lens element is concave; and an optical axis region of the image-side surface of the seventh lens element is convex, wherein lens elements of the optical imaging lens are only the eight lens elements, and satisfy conditions as follows: | V 4− V 5|≥30.000; and (G67+T7)/(G56+T6)≥1.500, wherein V4 is an Abbe number of the fourth lens element; V5 is an Abbe number of the fifth lens element; G67 is an air gap between the sixth lens element and the seventh lens element on the optical axis; T7 is a thickness of the seventh lens element on the optical axis; G56 is an air gap between the fifth lens element and the sixth lens element on the optical axis; and T6 is a thickness of the sixth lens element on the optical axis, wherein the air gap between the fifth lens element and the sixth lens element on the optical axis is less than the air gap between the sixth lens element and the seventh lens element on the optical axis.
4. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (G23+G78)/T4≥2.000, wherein G23 is an air gap between the second lens element and the third lens element on the optical axis; G78 is an air gap between the seventh lens element and the eighth lens element on the optical axis; and T4 is a thickness of the fourth lens element on the optical axis.
5. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: T1/(G12+T3)≥1.600, wherein T1 is a thickness of the first lens element on the optical axis; G12 is an air gap between the first lens element and the second lens element on the optical axis; and T3 is a thickness of the third lens element on the optical axis.
6. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (T1+T2+T3)/(G12+G78)≤2.100, wherein T1 is a thickness of the first lens element on the optical axis; T2 is a thickness of the second lens element on the optical axis; T3 is a thickness of the third lens element on the optical axis; G12 is an air gap between the first lens element and the second lens element on the optical axis; and G78 is an air gap between the seventh lens element and the eighth lens element on the optical axis.
7. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: EFL/(G23+G45+G67)≥5.000, wherein EFL is an effective focal length of the optical imaging lens; G23 is an air gap between the second lens element and the third lens element on the optical axis; and G45 is an air gap between the fourth lens element and the fifth lens element on the optical axis.
8. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (G12+BFL)/T7≤2.100, wherein G12 is an air gap between the first lens element and the second lens element on the optical axis, and BFL is a distance from the image-side surface of the eighth lens element to an image plane on the optical axis.
9. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: ImgH/BFL≥4.200, wherein ImgH is an image height of the optical imaging lens, and BFL is a distance from the image-side surface of the eighth lens element to an image plane on the optical axis.
10. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (T1+G12)/T2≥2.900, wherein T1 is a thickness of the first lens element on the optical axis; G12 is an air gap between the first lens element and the second lens element on the optical axis; and T2 is a thickness of the second lens element on the optical axis.
11. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (T2+T3+T6)/(G12+G45)≤3.600, wherein T2 is a thickness of the second lens element on the optical axis; T3 is a thickness of the third lens element on the optical axis; G12 is an air gap between the first lens element and the second lens element on the optical axis; and G45 is an air gap between the fourth lens element and the fifth lens element on the optical axis.
12. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (T7+G78+T8)/T6≥5.000, wherein G78 is an air gap between the seventh lens element and the eighth lens element on the optical axis, and T8 is a thickness of the eighth lens element on the optical axis.
13. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: EFL/AAG≥1.500, wherein EFL is an effective focal length of the optical imaging lens, and AAG is a sum of seven air gaps of the first lens element to the eighth lens element on the optical axis.
14. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (T2+T3+T4+T5)/G67≤4.000, wherein T2 is a thickness of the second lens element on the optical axis; T3 is a thickness of the third lens element on the optical axis; T4 is a thickness of the fourth lens element on the optical axis; and T5 is a thickness of the fifth lens element on the optical axis.
15. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (G23+G34+G45)/T3≥1.500, wherein G23 is an air gap between the second lens element and the third lens element on the optical axis; G34 is an air gap between the third lens element and the fourth lens element on the optical axis; G45 is an air gap between the fourth lens element and the fifth lens element on the optical axis; and T3 is a thickness of the third lens element on the optical axis.
16. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: ALT/(T7+G78)≤3.000, wherein ALT is a sum of the thicknesses of the eight lens elements from the first lens element to the eighth lens element on the optical axis, and G78 is an air gap between the seventh lens element and the eighth lens element on the optical axis.
17. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: TTL/(T1+T7+G78)≤3.300, wherein TTL is a distance from the object-side surface of the first lens element to an image plane on the optical axis; T1 is a thickness of the first lens element on the optical axis; and G78 is an air gap between the seventh lens element and the eighth lens element on the optical axis.
18. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: (G45+G56+T6)/T8≤2.500, wherein G45 is an air gap between the fourth lens element and the fifth lens element on the optical axis, and T8 is a thickness of the eighth lens element on the optical axis.
19. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: EFL/(T5+G56+T6)≥5.500, wherein EFL is an effective focal length of the optical imaging lens, and T5 is a thickness of the fifth lens element on the optical axis.
20. The optical imaging lens according to claim 3 , wherein the optical imaging lens further satisfies a condition as follows: TL/(T3+T4+T7)≤4.500, wherein TL is a distance from the object-side surface of the first lens element to the image-side surface of the eighth lens element on the optical axis; T3 is a thickness of the third lens element on the optical axis; and T4 is a thickness of the fourth lens element on the optical axis.
