Optical imaging lens assembly, image capturing unit and electronic device

1. An optical imaging lens assembly comprising eight lens elements, the eight lens elements being, in order from an object side to an image side along an optical path, 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, and each of the eight lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein the object-side surface of the first lens element is concave in a paraxial region thereof, the object-side surface of the first lens element has at least one inflection point in an off-axis region thereof, the object-side surface of the second lens element is convex in a paraxial region thereof, the image-side surface of the sixth lens element is convex in a paraxial region thereof, the seventh lens element has negative refractive power, the image-side surface of the eighth lens element is concave in a paraxial region thereof, the image-side surface of the eighth lens element has at least one inflection point in an off-axis region thereof, and at least one of the object-side surface and the image-side surface of at least one of 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 is aspheric;

wherein an axial distance between the sixth lens element and the seventh lens element is T 67 , an axial distance between the seventh lens element and the eighth lens element is T 78 , an f-number of the optical imaging lens assembly is Fno, a curvature radius of the image-side surface of the sixth lens element is R 12 , a focal length of the optical imaging lens assembly is f, and the following conditions are satisfied:

1.0<( T 67+ T 78)/| T 67− T 78|<6.0;

1.0< Fno< 3.0; and

−1.8< R 12/ f<− 0.10.

2. The optical imaging lens assembly of claim 1 , wherein the axial distance between the sixth lens element and the seventh lens element is T 67 , the axial distance between the seventh lens element and the eighth lens element is T 78 , and the following condition is satisfied:

1.0<( T 67+ T 78)/| T 67− T 78|<3.0.

3. The optical imaging lens assembly of claim 2 , wherein the axial distance between the sixth lens element and the seventh lens element is T 67 , the axial distance between the seventh lens element and the eighth lens element is T 78 , and the following condition is satisfied:

1.0<( T 67+ T 78)/| T 67− T 78|<1.5.

4. The optical imaging lens assembly of claim 1 , wherein an Abbe number of the first lens element is V 1 , an Abbe number of the second lens element is V 2 , an Abbe number of the third lens element is V 3 , an Abbe number of the fourth lens element is V 4 , an Abbe number of the fifth lens element is V 5 , an Abbe number of the sixth lens element is V 6 , an Abbe number of the seventh lens element is V 7 , an Abbe number of the eighth lens element is V 8 , and the following condition is satisfied:

1.2<( V 1+ V 4+ V 6+ V 8)/( V 2+ V 3+ V 5+ V 7)<3.2.

5. The optical imaging lens assembly of claim 1 , wherein an axial distance between the fourth lens element and the fifth lens element is T 45 , an axial distance between the fifth lens element and the sixth lens element is T 56 , an axial distance between the object-side surface of the first lens element and an image surface is TL, the focal length of the optical imaging lens assembly is f, an entrance pupil diameter of the optical imaging lens assembly is EPD, and the following conditions are satisfied:

1.0< T 45/ T 56<3.0;

1.2< TL/f< 4.5; and

3.0 <TL /EPD<6.5.

6. The optical imaging lens assembly of claim 1 , wherein at least one of the object-side surface and the image-side surface of at least one of 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 has at least one inflection point in an off-axis region thereof;

wherein the focal length of the optical imaging lens assembly is f, a focal length of the sixth lens element is f6, a focal length of the seventh lens element is f7, and the following condition is satisfied:

1.4< f/f 6− f/f 7<4.0.

7. The optical imaging lens assembly of claim 1 , wherein the first lens element has negative refractive power;

wherein a focal length of the first lens element is f1, a focal length of the seventh lens element is f7, and the following condition is satisfied:

0.78≤ f 1/ f 7<5.00.

8. The optical imaging lens assembly of claim 1 , wherein the first lens element has negative refractive power, and the sixth lens element has positive refractive power;

wherein the focal length of the optical imaging lens assembly 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, a focal length of the sixth lens element is f6, a focal length of the seventh lens element is f7, a focal length of the eighth lens element is f8, and the following conditions are satisfied:

−0.90< f/f 1<−0.10;

−0.50< f/f 2<0.70;

−1.0< f/f 3<1.0;

−1.0< f/f 4<1.2;

−0.80< f/f 5<0.80;

0.70< f/f 6<2.4;

−1.60< f/f 7<−0.40; and

−0.50< f/f 8<0.50.

9. The optical imaging lens assembly of claim 1 , wherein a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of the image-side surface of the eighth lens element is R16, and the following condition is satisfied:

−6.0< R 1/ R 16<0;

wherein a vertical distance between a critical point on the object-side surface of the first lens element and an optical axis is Yc 11 , a maximum effective radius of the object-side surface of the first lens element is Y 11 , and at least one convex critical point on the object-side surface of the first lens element in the off-axis region satisfies the following condition:

0.10< Yc 11/ Y 11<0.50.

10. The optical imaging lens assembly of claim 1 , wherein the sixth lens element has positive refractive power;

wherein the curvature radius of the image-side surface of the sixth lens element is R12, the focal length of the optical imaging lens assembly is f, and the following condition is satisfied:

−0.55< R 12/ f<− 0.15.

11. An image capturing unit, comprising:

the optical imaging lens assembly of claim 1 ; and

an image sensor disposed on an image surface of the optical imaging lens assembly.

12. An electronic device, comprising:

the image capturing unit of claim 11 .