Imaging optical lens assembly, image capturing unit and electronic device

1. An imaging optical lens assembly comprising six lens elements, the six 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 and a sixth lens element; each of the six lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein at least one of the six lens elements has at least one aspheric surface having at least one inflection point, a focal length of the imaging optical lens assembly is f, an axial distance between the object-side surface of the first lens element and an image surface is TL, a curvature radius of the object-side surface of the first lens element is R1, an entrance pupil diameter of the imaging optical lens assembly is EPD, a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the image-side surface of the sixth lens element is Y62, a minimum value among all Abbe numbers of the six lens elements of the imaging optical lens assembly is Vmin, an Abbe number of the fifth lens element is V5, an Abbe number of the sixth lens element is V6, and the following conditions are satisfied:

2.0<f/(f−TL);

−10.0<TL/R1<1.8;

1.0<TL/EPD<5.0;

0.55<Y11/Y62≤1.8;

10.0<Vmin<21.3;

20.0<V5+V6<105.0;

1.0 [mm]<TL<17.0 [mm] and 10.0<V5<45.0.

2. The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, the axial distance between the object-side surface of the first lens element and the image surface is TL, a maximum value among all refractive indices of the six lens elements of the imaging optical lens assembly is Nmax, a chief ray angle at a maximum image height of the imaging optical lens assembly is CRA, and the following conditions are satisfied:

2.5<f/(f−TL)<100.0;

1.65<Nmax<1.75; and

CRA<25.0 [deg.].

3. The imaging optical lens assembly of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, the curvature radius of the object-side surface of the first lens element is R1, and the following condition is satisfied:

−5.0<TL/R1<1.4.

4. The imaging optical lens assembly of claim 1 , wherein the Abbe number of the fifth lens element is V5, the Abbe number of the sixth lens element is V6, and the following condition is satisfied:

25.0<V5+V6<90.0.

5. The imaging optical lens assembly of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, the entrance pupil diameter of the imaging optical lens assembly is EPD, and the following condition is satisfied:

1.2<TL/EPD<4.0.

6. The imaging optical lens assembly of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, a maximum image height of the imaging optical lens assembly is ImgH, a maximum value among maximum effective radii of all lens surfaces of the six lens elements of the imaging optical lens assembly is Ymax, a minimum value among maximum effective radii of all lens surfaces of the six lens elements of the imaging optical lens assembly is Ymin, and the following conditions are satisfied:

2.0 [mm]<TL<15.0 [mm];

1.5<TL/ImgH<7.0; and

1.0<Ymax/Ymin<2.0.

7. The imaging optical lens assembly of claim 1 , 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 sixth lens element is Y62, and the following condition is satisfied:

0.65<Y11/Y62≤1.54.

8. The imaging optical lens assembly of claim 1 , wherein each of at least three of the six lens elements has at least one aspheric surface having at least one inflection point, half of a maximum field of view of the imaging optical lens assembly is HFOV, and the following condition is satisfied:

5.0 [deg.]<HFOV<32.0 [deg.].

9. The imaging optical lens assembly of claim 1 , wherein a maximum value among all axial distances between every adjacent lens element of the six lens elements is ATmax, an axial distance between the object-side surface of the first lens element and the image-side surface of the sixth lens element is TD, and the following condition is satisfied:

0<ATmax/TD<0.40.

10. The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, a focal length of the first lens element is f1, and the following condition is satisfied:

−0.50<f/f1<1.0.

11. The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, a minimum value among all absolute values of focal lengths of each of the six lens elements of the imaging optical lens assembly is |f|min, and the following condition is satisfied:

1.40<f/|f|min.

12. The imaging optical lens assembly of claim 1 , wherein the second lens element has positive refractive power, and the third lens element has negative refractive power.

13. An image capturing unit, comprising:

the imaging optical lens assembly of claim 1 ; and

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

14. An electronic device, comprising:

the image capturing unit of claim 13 .

15. An imaging optical lens assembly comprising six lens elements, the six 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 and a sixth lens element; each of the six lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

wherein at least one of the six lens elements has at least one aspheric surface having at least one inflection point, a focal length of the imaging optical lens assembly is f, an axial distance between the object-side surface of the first lens element and an image surface is TL, a curvature radius of the object-side surface of the first lens element is R1, an entrance pupil diameter of the imaging optical lens assembly is EPD, a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the image-side surface of the sixth lens element is Y62, a sum of axial distances between every adjacent lens element of the six lens elements is ΣAT, a sum of central thicknesses of the six lens elements of the imaging optical lens assembly is ΣCT, an Abbe number of the fifth lens element is V5, a minimum value among all absolute values of focal lengths of each of the six lens elements of the imaging optical lens assembly is |f|min, half of a maximum field of view of the imaging optical lens assembly is HFOV, and the following conditions are satisfied:

2.0<f/(f−TL);

−10.0<TL/R1<1.8;

1.2<TL/EPD<4.0;

0.55<Y11/Y62≤1.8;

0<ΣAT/ΣCT<1.6;

10.0<V5<45.0;

1.40<f/|f|min; and

5.0 [deg.]<HFOV<32.0 [deg.].

16. The imaging optical lens assembly of claim 15 , wherein the focal length of the imaging optical lens assembly is f, the axial distance between the object-side surface of the first lens element and the image surface is TL, and the following conditions are satisfied:

2.5<f/(f−TL)<100.0; and

2.0 [mm]<TL<15.0 [mm].

17. The imaging optical lens assembly of claim 16 , wherein a maximum value among all axial distances between every adjacent lens element of the six lens elements is ATmax, an axial distance between the object-side surface of the first lens element and the image-side surface of the sixth lens element is TD, and the following condition is satisfied:

0<ATmax/TD<0.40.

18. The imaging optical lens assembly of claim 16 , wherein the focal length of the imaging optical lens assembly is f, a focal length of the first lens element is f1, and the following condition is satisfied:

−0.50<f/f1<1.0.

19. The imaging optical lens assembly of claim 16 , wherein an f-number of the imaging optical lens assembly is Fno, a chief ray angle at a maximum image height of the imaging optical lens assembly is CRA, a maximum value among maximum effective radii of all lens surfaces of the six lens elements of the imaging optical lens assembly is Ymax, a minimum value among maximum effective radii of all lens surfaces of the six lens elements of the imaging optical lens assembly is Ymin, and the following conditions are satisfied:

1.9<Fno<5.0;

CRA<25.0 [deg.]; and

1.0<Ymax/Ymin<2.0.

20. The imaging optical lens assembly of claim 16 , further comprising an aperture stop, wherein a maximum value among maximum effective radii of all lens surfaces of the six lens elements of the imaging optical lens assembly is Ymax, an aperture radius of the aperture stop is Ystop, and the following condition is satisfied:

0<Ymax/Ystop<2.40.

21. The imaging optical lens assembly of claim 16 , wherein at least three of the six lens elements of the imaging optical lens assembly are made of plastic material, the focal length of the imaging optical 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, the minimum value among all absolute values of focal lengths of each of the six lens elements of the imaging optical lens assembly is |f|min, and the following conditions are satisfied:

−2.0<f/f1<5.0;

−5.0<f/f2<5.0;

−5.0<f/f3<5.0;

−5.0<f/f4<5.0;

−5.0<f/f5<5.0;

−5.0<f/f6<5.0; and

1.70<f/|f|min<5.0.

22. The imaging optical lens assembly of claim 15 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, the curvature radius of the object-side surface of the first lens element is R1, and the following condition is satisfied:

−5.0<TL/R1<1.4.

23. The imaging optical lens assembly of claim 15 , wherein the Abbe number of the fifth lens element is V5, and the following condition is satisfied:

12.0<V5<38.0.

24. The imaging optical lens assembly of claim 15 , wherein a maximum effective radius of the object-side surface of the first lens element is Y11, a maximum effective radius of the image-side surface of the sixth lens element is Y62, and the following condition is satisfied:

0.65<Y11/Y62≤1.54.

25. The imaging optical lens assembly of claim 15 , wherein half of the maximum field of view of the imaging optical lens assembly is HFOV, and the following condition is satisfied:

6.0 [deg.]<HFOV<25.0 [deg.].

26. The imaging optical lens assembly of claim 15 , wherein each of at least three of the six lens elements has at least one aspheric surface having at least one inflection point.

27. An image capturing unit, comprising:

the imaging optical lens assembly of claim 15 ; and

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

28. An electronic device, comprising:

the image capturing unit of claim 27 .