Photographing lens assembly, image capturing unit and electronic device
A photographing lens assembly includes, in order from an object side to an image side: a first, a second, a third, a fourth, a fifth and a sixth lens elements. The first lens element with negative refractive power has an object-side surface being concave in a paraxial region thereof, wherein the object-side surface has at least one convex critical point in an off-axis region thereof. The third lens element has an image-side surface being convex in a paraxial region thereof. The fourth lens element has positive refractive power. The fifth lens element with negative refractive power has an object-side surface being concave in a paraxial region thereof, and an image-side surface being convex in a paraxial region thereof. The sixth lens element has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface has at least one convex critical point in an off-axis region thereof.
1. A photographing 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 with negative refractive power having an object-side surface being concave in a paraxial region thereof, wherein the object-side surface of the first lens element has at least one convex critical point in an off-axis region thereof;
a second lens element;
a third lens element having an image-side surface being convex in a paraxial region thereof;
a fourth lens element having positive refractive power;
a fifth lens element with negative refractive power having an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof; and
a sixth lens element having an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the sixth lens element has at least one convex critical point in an off-axis region thereof, and an object-side surface and the image-side surface of the sixth lens element are both aspheric;
wherein a curvature radius of the object-side surface of the first lens element is R 1 , a curvature radius of an image-side surface of the first lens element is R 2 , a central thickness of the sixth lens element is CT 6 , an axial distance between the fifth lens element and the sixth lens element is T 56 , an axial distance between the first lens element and the second lens element is T 12 , an axial distance between the second lens element and the third lens element is T 23 , and the following conditions are satisfied:
| R 1/ R 2|<5.0;
1.60< CT 6/ T 56<100; and
0.68< T 12/ T 23<1.60.
2. The photographing lens assembly of claim 1 , wherein a maximum field of view of the photographing lens assembly is FOV, an f-number of the photographing lens assembly is FNo, and the following conditions are satisfied:
100 [deg.]<FOV<200 [deg.]; and
1.25< FNo< 3.0.
3. The photographing lens assembly of claim 1 , wherein a focal length of the fourth lens element is f 4 , a focal length of the fifth lens element is f 5 , and the following condition is satisfied:
| f 5/ f 4|<1.50.
4. The photographing lens assembly of claim 1 , wherein the second lens element has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof.
5. The photographing lens assembly of claim 1 , wherein the central thickness of the sixth lens element is CT 6 , the axial distance between the fifth lens element and the sixth lens element is T 56 , and the following condition is satisfied:
2.0< CT 6/ T 56<100.
6. The photographing lens assembly of claim 1 , wherein a focal length of the first lens element is f 1 , a focal length of the sixth lens element is f 6 , and the following condition is satisfied:
| f 1/ f 6|<1.0.
7. The photographing lens assembly of claim 1 , wherein a maximum effective radius of the object-side surface of the first lens element is Y 1 R 1 , a maximum effective radius of the image-side surface of the sixth lens element is Y 6 R 2 , and the following condition is satisfied:
0.60< Y 1 R 1/ Y 6 R 2<1.0.
8. The photographing lens assembly of claim 1 , wherein each of at least two lens elements among the second through the fifth lens elements has at least one critical point in an off-axis region thereof.
9. The photographing lens assembly of claim 1 , wherein a curvature radius of an object-side surface of the third lens element is R 5 , a curvature radius of the image-side surface of the third lens element is R 6 , and the following condition is satisfied:
0.25<( R 5+ R 6)/( R 5− R 6)<1.50.
10. The photographing lens assembly of claim 1 , wherein the sixth lens element has positive refractive power, and the object-side surface of the sixth lens element is convex in a paraxial region thereof.
11. The photographing lens assembly of claim 1 , wherein a focal length of the photographing lens assembly is f, a curvature radius of an object-side surface of the second lens element is R 3 , a curvature radius of an image-side surface of the second lens element is R 4 , and the following condition is satisfied:
1.5<( f/R 3)+( f/R 4)<5.0.
12. The photographing lens assembly of claim 1 , wherein the axial distance between the first lens element and the second lens element is T 12 , the axial distance between the second lens element and the third lens element is T 23 , an axial distance between the third lens element and the fourth lens element is T 34 , an axial distance between the fourth lens element and the fifth lens element is T 45 , the axial distance between the fifth lens element and the sixth lens element is T 56 , and the following condition is satisfied:
0.35<( T 12+ T 56)/( T 23+ T 34+ T 45)<1.75.
13. The photographing lens assembly of claim 1 , wherein a focal length of the photographing lens assembly is f, the central thickness of the sixth lens element is CT 6 , and the following condition is satisfied:
f/CT 6<3.60.
14. The photographing lens assembly of claim 1 , wherein a displacement in parallel with an optical axis from an axial vertex of the image-side surface of the fifth lens element to a maximum effective radius position of the image-side surface of the fifth lens element is Sag 52 , a central thickness of the fifth lens element is CT 5 , and the following condition is satisfied:
−0.75< Sag 52/ CT 5<0.25.
15. The photographing lens assembly of claim 1 , further comprising an aperture stop disposed between the second lens element and the third lens element.
16. The photographing 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 curvature radius of the object-side surface of the first lens element is R 1 , and the following condition is satisfied:
−5.0< TL/R 1<−0.50.
17. The photographing lens assembly of claim 1 , wherein a focal length of the photographing lens assembly is f, a focal length of the second lens element is f 2 , a focal length of the sixth lens element is f 6 , a focal length of the i-th lens element is fi, and the following condition is satisfied:
| f/f 2|+| f/ 6|<| f/fi|,
wherein i=1, 3, 4, 5.
18. The photographing lens assembly of claim 1 , wherein the second lens element has positive refractive power.
19. An image capturing unit, comprising:
the photographing lens assembly of claim 1 ; and
an image sensor disposed on an image surface of the photographing lens assembly.
20. An electronic device, comprising:
the image capturing unit of claim 19 .