Photographing optical lens assembly including seven lenses of +-++--+, +---+-+, +--+--+, +--++-+, +-+---+ OR +-+-+-- refractive powers, image capturing device and electronic device
A photographing optical lens assembly includes, 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. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The second lens element has negative refractive power. The sixth lens element has at least one of an object-side surface and an image-side surface being aspheric, wherein at least one of the object-side surface and the image-side surface of the sixth lens element comprises at least one inflection point. The seventh lens element has an object-side surface and an image-side surface being both aspheric.
1. A photographing optical 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; each of the seven lens elements having an object-side surface facing towards the object side and an image-side surface facing towards the image side;
wherein the first lens element has positive refractive power; the third lens element has the image-side surface being concave in a paraxial region thereof; the image-side surface of the sixth lens element comprises at least one inflection point; the image-side surface of the seventh lens element comprises at least one inflection point;
wherein an absolute value of a curvature radius of the object-side surface of the fourth lens element is smaller than an absolute value of a curvature radius of the image-side surface of the first lens element; a central thickness of the seventh lens element is smaller than a central thickness of the first lens element; an axial distance between the second lens element and the third lens element is smaller than an axial distance between the fourth lens element and the fifth lens element;
wherein at least one lens element with positive refractive power of the seven lens elements has an Abbe number smaller than 25.
2. The photographing optical lens assembly of claim 1 , wherein the first lens element has the object-side surface being convex in a paraxial region thereof, the second lens element has the object-side surface being convex in a paraxial region thereof; the fourth lens element has the object-side surface being convex in a paraxial region thereof; the fifth lens element has positive refractive power.
3. The photographing optical lens assembly of claim 1 , wherein the third lens element has negative refractive power; the photographing optical lens assembly further comprises an aperture stop disposed on an object side of the third lens element.
4. The photographing optical lens assembly of claim 1 , wherein the seventh lens element has the image-side surface being concave in a paraxial region thereof; an absolute value of a curvature radius of the image-side surface of the seventh lens element is smaller than the absolute value of the curvature radius of the image-side surface of the first lens element.
5. The photographing optical lens assembly of claim 1 , wherein a focal length of the photographing optical lens assembly is f, a maximal image height of the photographing optical lens assembly is ImgH, and the following condition is satisfied:
2.20< f/ImgH< 5.50.
6. The photographing optical lens assembly of claim 1 , wherein a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, a central thickness of the sixth lens element is CT6, and the following condition is satisfied:
0.5< Yc 62/ CT 6<7.5.
7. The photographing optical lens assembly of claim 1 , wherein both of the object-side surface and the image-side surface of each of the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element are aspheric; the fourth lens element comprises at least one inflection point; a focal length of the second lens element and a focal length of the fourth lens element have the same sign.
8. The photographing optical lens assembly of claim 1 , wherein an absolute value of a curvature radius of the image-side surface of the third lens element is smaller than an absolute value of a curvature radius of the object-side surface of the third lens element.
9. The photographing optical lens assembly of claim 1 , wherein an absolute value of a focal length of the first lens element is smaller than an absolute value of a focal length of the sixth lens element; the axial distance between the second lens element and the third lens element is smaller than an axial distance between the fifth lens element and the sixth lens element.
10. The photographing optical lens assembly of claim 1 , wherein the sixth lens element has negative refractive power.
11. An image capturing device, comprising:
the photographing optical lens assembly of claim 1 ; and
an image sensor disposed on an image surface of the photographing optical lens assembly.
12. An electronic device, comprising:
the image capturing device of claim 11 .
13. A photographing optical 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; each of the seven lens elements having an object-side surface facing towards the object side and an image-side surface facing towards the image side;
wherein the third lens element has the image-side surface being concave in a paraxial region thereof; the fifth lens element has positive refractive power; the image-side surface of the sixth lens element comprises at least one inflection point;
wherein a focal length of the second lens element and a focal length of the seventh lens element have different signs; an absolute value of a focal length of the first lens element is smaller than an absolute value of a focal length of the sixth lens element; a central thickness of the seventh lens element is smaller than a central thickness of the first lens element;
wherein at least one lens element with positive refractive power of the seven lens elements has an Abbe number smaller than 25.
14. The photographing optical lens assembly of claim 13 , wherein the first lens element has positive refractive power; the third lens element has negative refractive power; the second lens element has the object-side surface being convex in a paraxial region thereof; the fifth lens element has the image-side surface being convex in a paraxial region thereof.
15. The photographing optical lens assembly of claim 13 , wherein a focal length of the photographing optical lens assembly is f, a maximal image height of the photographing optical lens assembly is ImgH, and the following condition is satisfied:
2.20< f/ImgH< 5.50.
16. The photographing optical lens assembly of claim 13 , wherein there is an air gap between each of adjacent lens elements of the seven lens elements; a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, a central thickness of the sixth lens element is CT6, and the following condition is satisfied:
0.5< Yc 62/ CT 6<7.5.
17. The photographing optical lens assembly of claim 13 , wherein an absolute value of a curvature radius of the object-side surface of the fourth lens element is smaller than an absolute value of a curvature radius of the image-side surface of the first lens element; an absolute value of a curvature radius of the image-side surface of the sixth lens element is smaller than the absolute value of the curvature radius of the image-side surface of the first lens element.
18. The photographing optical lens assembly of claim 13 , wherein the fourth lens element comprises at least one inflection point; the focal length of the second lens element and a focal length of the fourth lens element have the same sign.
19. The photographing optical lens assembly of claim 13 , wherein the second lens element has negative refractive power.