Optical imaging lens assembly, image capturing unit and electronic device

1. An optical imaging lens assembly comprising seven lens elements, the seven lens elements being, 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, wherein the seventh lens element has an image-side surface being concave in a paraxial region thereof, at least one of an object-side surface and the image-side surface of the seventh lens element has at least one critical point in an off-axis region thereof, the object-side surface and the image-side surface of the seventh lens element are both aspheric;

wherein 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, a maximum effective radius of the image-side surface of the seventh lens element is Y72, a chief ray with an incident angle of 55 degrees relative to an optical axis is CR, an intersection point between CR and the image-side surface of the seventh lens element is P, a vertical distance from the optical axis to P is Yc_55, a maximum image height of the optical imaging lens assembly is ImgH, and the following conditions are satisfied:

Td/|Y 72|<1.80; and

0.30<| Yc _55|/Img H< 0.95.

2. The optical imaging lens assembly of claim 1 , wherein an axial distance between the object-side surface of the first lens element and an image surface is TL, the maximum image height of the optical imaging lens assembly is ImgH, a maximum field of view of the optical imaging lens assembly is FOV, an f-number of the optical imaging lens assembly is Fno, and the following conditions are satisfied:

TL /Img H< 2.0;

110 [deg.]<FOV<220 [deg.]; and

1.0<Fno<2.40.

3. The optical imaging lens assembly of claim 1 , wherein a maximum effective radius of the object-side surface of the first lens element is Y11, the maximum effective radius of the image-side surface of the seventh lens element is Y72, and the following condition is satisfied:

| Y 11/ Y 72|<1.20.

4. The optical imaging lens assembly of claim 3 , wherein the maximum effective radius of the object-side surface of the first lens element is Y11, the maximum effective radius of the image-side surface of the seventh lens element is Y72, and the following condition is satisfied:

| Y 11/ Y 72|<0.90.

5. The optical imaging lens assembly of claim 1 , wherein the seventh lens element has negative refractive power.

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

7. The optical imaging lens assembly of claim 1 , wherein a 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, and the following condition is satisfied:

| f/f 1|+| f/f 2|<0.70.

8. 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 an image-side surface of the first lens element is R2, a curvature radius of an object-side surface of the second lens element is R3, a curvature radius of an image-side surface of the second lens element is R4, a curvature radius of an object-side surface of the third lens element is R5, a curvature radius of an image-side surface of the third lens element is R6, a curvature radius of an object-side surface of the fourth lens element is R7, a curvature radius of an image-side surface of the fourth lens element is R8, 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, a curvature radius of an object-side surface of the sixth lens element is R11, a curvature radius of an image-side surface of the sixth lens element is R12, 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 conditions are satisfied:

| R 14/ R 1|<1.0;

| R 14/ R 2|<1.0;

| R 14/ R 3|<1.0;

| R 14/ R 4|<1.0;

| R 14/ R 5|<1.0;

| R 14/ R 6|<1.0;

| R 14/ R 7|<1.0;

| R 14/ R 8|<1.0;

| R 14/ R 9|<1.0;

| R 14/ R 10|<1.0;

| R 14/ R 11|<0.0;

| R 14/ R 12|<1.0; and

| R 14/ R 13|<0.0.

9. The optical imaging lens assembly of claim 1 , wherein a vertical distance between a convex critical point closest to a maximum effective radius position on an image-side surface of the sixth lens element and the optical axis is Yc62, a vertical distance between a convex critical point closest to a maximum effective radius position on the image-side surface of the seventh lens element and the optical axis is Yc72, and the following condition is satisfied:

0.50<| Yc 62/ Yc 72|<1.5.

10. The optical imaging lens assembly of claim 1 , further comprising an aperture stop disposed between an imaged object and an object-side surface of the third lens element.

11. The optical imaging lens assembly of claim 1 , wherein the sixth lens element is meniscus in a paraxial region thereof.

12. The optical imaging lens assembly of claim 1 , wherein a number of lens elements having an Abbe number smaller than 20 among the seven lens elements is V20, and the following condition is satisfied:

2≤ V 20.

13. The optical imaging lens assembly of claim 1 , wherein a focal length of the optical imaging lens assembly is f, a curvature radius of an image-side surface of the sixth lens element is R12, and the following condition is satisfied:

0≤ f/R 12.

14. The optical imaging lens assembly of claim 1 , wherein the maximum effective radius of the image-side surface of the seventh lens element is Y72, a focal length of the optical imaging lens assembly is f, and the following condition is satisfied:

1.0<| Y 72|/ f.

15. The optical imaging lens assembly of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image-side surface of the seventh lens element is Td, the maximum effective radius of the image-side surface of the seventh lens element is Y72, and the following condition is satisfied:

1.0< Td/|Y 72|<1.60.

16. The optical imaging lens assembly of claim 1 , wherein the object-side surface of the seventh lens element is convex in a paraxial region thereof.

17. The optical imaging lens assembly of claim 1 , wherein the fourth lens element has negative refractive power.

18. The optical imaging lens assembly of claim 1 , further comprising an aperture stop, wherein a maximum effective radius of the object-side surface of the first lens element is Y11, an aperture radius of the aperture stop is Ystop, and the following condition is satisfied:

| Y 11 /Y stop|<2.0.

19. The optical imaging lens assembly of claim 1 , wherein the fifth lens element has an image-side surface being convex in a paraxial region thereof.

20. The optical imaging lens assembly of claim 1 , wherein a curvature radius of the image-side surface of the seventh lens element is R14, the maximum effective radius of the image-side surface of the seventh lens element is Y72, and the following condition is satisfied:

0< R 14/| Y 72|<0.50.

21. 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.

22. An electronic device, comprising:

the image capturing unit of claim 21 .