Photographing optical lens assembly, image capturing unit and electronic device
A photographing optical lens assembly includes, in order from object side to 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. The first lens element has positive refractive power. The second, third, fourth and fifth lens elements have refractive power. The sixth lens element with refractive power has an image-side surface being concave in a paraxial region, wherein an object-side surface and the image-side surface of the sixth lens element are both aspheric, and the image-side surface has at least one inflection point. The seventh lens element with refractive power has an image-side surface being concave in a paraxial region, wherein an object-side surface and the image-side surface of the seventh lens element are both aspheric, and the image-side surface has at least one inflection point.
1. A photographing optical lens assembly comprising seven lens elements, and 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 second lens element has an object-side surface being convex in a paraxial region thereof, an image-side surface of the sixth lens element has at least one inflection point, a curvature radius of an object-side surface of the first lens element has a same sign as a curvature radius of an image-side surface of the third lens element, and an absolute value of a curvature radius of an image-side surface of the fourth lens element is larger than an absolute value of a curvature radius of an object-side surface of the fifth lens element;
wherein a curvature radius of an object-side surface of the sixth lens element is R11, a curvature radius of the image-side surface of the sixth lens element is R12, a curvature radius of an image-side surface of the seventh lens element is R14, a focal length of the photographing optical lens assembly is f, and the following conditions are satisfied:
−2.0<( R 11− R 12)/( R 11+ R 12)<0.2; and
0< R 14/ f< 0.7.
2. The photographing optical lens assembly of claim 1 , wherein the first lens element has an image-side surface being concave in a paraxial region thereof, and the image-side surface of the seventh lens element has at least one inflection point.
3. The photographing optical lens assembly of claim 1 , wherein the sixth lens element has positive refractive power, both of the object-side surface and the image-side surface of the sixth lens element are aspheric, and both of an object-side surface and the image-side surface of the seventh lens element are aspheric.
4. The photographing optical lens assembly of claim 1 , wherein the focal length of the photographing optical lens assembly is f, the curvature radius of the image-side surface of the sixth lens element is R12, and the following condition is satisfied:
0< f/R 12<5.0.
5. The photographing optical lens assembly of claim 1 , wherein the focal length of the photographing optical lens assembly is f, an entrance pupil diameter of the photographing optical lens assembly is EPD, an axial distance between the object-side surface of the first lens element and an image surface is TL, a maximum image height of the photographing optical lens assembly is ImgH, and the following conditions are satisfied:
1.2< f/EPD< 2.6; and
TL /Img H <2.20.
6. The photographing optical 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 focal length of the photographing optical lens assembly is f, and the following condition is satisfied:
0.80< TL/f< 1.80.
7. The photographing optical lens assembly of claim 1 , wherein a curvature radius of an object-side surface of the seventh lens element is R13, the curvature radius of the image-side surface of the seventh lens element is R14, a central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, and the following conditions are satisfied:
0<( R 13− R 14)/( R 13+ R 14)<1.5; and
1.0< CT 1/ CT 2<5.5.
8. The photographing optical lens assembly of claim 1 , further comprising a stop, wherein an axial distance between the stop and the image-side surface of the seventh lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the seventh lens element is TD, and the following condition is satisfied:
0.75< SD/TD< 1.1.
9. The photographing optical lens assembly of claim 1 , wherein an axial distance between the second lens element and the third lens element is T23, a central thickness of the second lens element is CT2, the focal length of the photographing optical lens assembly is f, and the following conditions are satisfied:
0.3< T 23/ CT 2<3.0; and
3.0 millimeters< f< 6.5 millimeters.
10. The photographing optical lens assembly of claim 1 , wherein a curvature radius of an object-side surface of the seventh lens element has a same sign as the curvature radius of the image-side surface of the seventh lens element.
11. The photographing optical lens assembly of claim 1 , wherein a central thickness of the seventh lens element is larger than an axial distance between the fifth lens element and the sixth lens element.
12. The photographing optical lens assembly of claim 1 , wherein a curvature radius of the object-side surface of the second lens element has a same sign as a curvature radius of an object-side surface of the third lens element.
13. The photographing optical lens assembly of claim 1 , wherein the first lens element has positive refractive power, and the fourth lens element has positive refractive power.
14. An image capturing unit, comprising:
the photographing optical lens assembly of claim 1 ; and
an image sensor disposed on an image surface of the photographing optical lens assembly.
15. An electronic device, comprising:
the image capturing unit of claim 14 .
16. A photographing optical lens assembly comprising seven lens elements, and 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 third lens element has positive refractive power, an image-side surface of the sixth lens element has at least one inflection point, an image-side surface of the seventh lens element has at least one inflection point, a curvature radius of an object-side surface of the first lens element has a same sign as a curvature radius of an image-side surface of the third lens element, and an absolute value of a curvature radius of an image-side surface of the fourth lens element is larger than an absolute value of a curvature radius of an object-side surface of the second lens element;
wherein a focal length of the photographing 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, a focal length of the seventh lens element is f7, a focal length of the j-th lens element is fj, a maximum absolute value among the ratios of f/f1, f/f2, f/f3, f/f4, f/f5, f/f6 and f/f7 is |f/fj|max, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, and the following conditions are satisfied:
| f/fj |max<1.8, wherein j= 1,2,3,4,5,6,7; and
0.5< T 23/ T 34<4.5.
17. The photographing optical lens assembly of claim 16 , wherein the sixth lens element has an object-side surface being convex in a paraxial region thereof.
18. The photographing optical lens assembly of claim 16 , wherein the seventh lens element has an object-side surface being convex in a paraxial region thereof and the image-side surface being concave in a paraxial region thereof.
19. The photographing optical lens assembly of claim 16 , wherein the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the seventh lens element is f7, and the following conditions are satisfied:
| f 1/ f 7|<3.0; and
| f 1/ f 2|<2.0.
20. The photographing optical lens assembly of claim 16 , wherein the focal length of the photographing optical lens assembly is f, the focal length of the third lens element is f3, the curvature radius of the image-side surface of the third lens element is R6, an axial distance between the first lens element and the second lens element is T12, the axial distance between the second lens element and the third lens element is T23, the axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, an axial distance between the fifth lens element and the sixth lens element is T56, an axial distance between the sixth lens element and the seventh lens element is T67, and the following conditions are satisfied:
0.01≤ f/f 3<0.6;
−1.0< f/R 6<2.5; and
0<( T 12/ T 23)+( T 34/ T 45)+( T 56/ T 67)<3.8.
21. The photographing optical lens assembly of claim 16 , wherein a sum of axial distances between any two lens elements adjacent to each other is ΣAT, a maximum image height of the photographing optical lens assembly is ImgH, and the following condition is satisfied:
0.20<Σ AT /Img H <0.60.
22. The photographing optical lens assembly of claim 16 , wherein a maximum refractive index among the seven lens elements is Nmax, and the following condition is satisfied:
1.640≤ N max<1.750.
23. The photographing optical lens assembly of claim 16 , wherein a curvature radius of the object-side surface of the second lens element has a same sign as a curvature radius of an object-side surface of the seventh lens element.
24. The photographing optical lens assembly of claim 16 , wherein the curvature radius of the object-side surface of the first lens element has a same sign as a curvature radius of an object-side surface of the fourth lens element, and the curvature radius of the image-side surface of the third lens element has a same sign as the curvature radius of the object-side surface of the fourth lens element.
25. The photographing optical lens assembly of claim 16 , wherein a vertical distance between a non-axial critical point on an object-side surface of the sixth lens element and an optical axis is Yc61, a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and the optical axis is Yc62, a vertical distance between a non-axial critical point on the image-side surface of the seventh lens element and the optical axis is Yc72, the focal length of the photographing optical lens assembly is f, and the following conditions are satisfied:
0.30< Yc 62/ Yc 61<1.80;
0.5< Yc 62/ Yc 72<1.5; and
0.1< Yc 72/ f< 0.9.
26. The photographing optical lens assembly of claim 16 , wherein the first lens element has positive refractive power, and the fourth lens element has positive refractive power.