Imaging optical lens assembly, imaging apparatus and electronic device
An imaging optical lens assembly includes seven lens elements, in order from an object side to an image side along an optical path, are 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 has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The first lens element has negative refractive power. The object-side surface of the first lens element is concave in a paraxial region thereof and the image-side surface of the first lens element is convex in a paraxial region thereof. The object-side surface of the second lens element is convex in a paraxial region thereof. With specific conditions being satisfied, the imaging optical lens assembly can be miniaturized while providing superior image quality.
1 . An imaging optical lens assembly comprising seven lens elements, the seven lens elements being, in order from an object side to an image side along an optical path: 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 first through seventh lens elements having an object-side surface facing the object side and an image-side surface facing the image side:
wherein the first lens element has negative refractive power, the object-side surface of the first lens element is concave in a paraxial region thereof and the image-side surface of the first lens element is convex in a paraxial region thereof, the image-side surface of the seventh lens element has at least one inflection point;
wherein a total number of lens elements with refractive power of the imaging optical lens assembly is seven, the seven lens elements with refractive power being the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element, and the seventh lens element: a focal length of the imaging optical lens assembly is f, a composite focal length of the first lens element and the second lens element is f12, a focal length of the fifth lens element is f5, a curvature radius of the image-side surface of the sixth lens element is R12, a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of the image-side surface of the first lens element is R2, and the following conditions are satisfied:
−2.50< f/f 12<−0.10;
−0.70< f/f 5<2.50;
−2.40< f/R 1<−0.65;
−1.50< f/R 12<−0.10; and
0.18< R 1/ R 2<0.80.
2 . The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, the curvature radius of the object-side surface of the first lens element is R1, and the following condition is satisfied:
−1.75< f/R 1<−1.10.
3 . The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, the focal length of the fifth lens element is f5, a composite focal length of the first lens element, the second lens element, the third lens element and the fourth lens element is f1234, and the following conditions are satisfied:
−0.60< f/f 5<0.60; and
0.25< f/f 1234<1.50.
4 . The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging 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:
−1.40< f/R 12<−0.40.
5 . The imaging optical lens assembly of claim 1 , wherein the focal length of the imaging optical lens assembly is f, a composite focal length of the third lens element, the fourth lens element and the fifth lens element is f345, and the following condition is satisfied:
−0.20< f/f 345<1.00.
6 . The imaging optical lens assembly of claim 1 , wherein 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, a sum of all axial distances between each of adjacent lens elements of the imaging optical lens assembly is ΣAT, and the following condition is satisfied:
0.00<( T 45+ T 56+ T 67)/τ AT< 0.49.
7 . The imaging optical lens assembly of claim 1 , wherein a refractive index of the second lens element is N2, the focal length of the imaging optical lens assembly is f, a focal length of the first lens element is f1, and the following conditions are satisfied:
1.63< N 2<1.95; and
−0.82< f/f 1<−0.30.
8 . The imaging optical lens assembly of claim 1 , wherein 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, an axial distance between the object-side surface of the first lens element and an image surface is TL, and the following condition is satisfied:
0.50< TD/TL< 0.82.