Imaging optical lens assembly including nine lenses of −++−++−+−, ++−++−−+−, −+−++−−+−, −+−++−++−, +−−++−−+− or +−−++−++− refractive powers, image capturing unit and electronic device

An imaging optical lens assembly comprising nine lens elements, and the nine 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, a seventh lens element, an eighth lens element and a ninth lens element;

• wherein the first lens element has an image-side surface being concave in a paraxial region thereof, the second lens element has positive refractive power, the eighth lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof, the ninth lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, and the image-side surface of the ninth lens element has at least one convex critical point in an off-axis region thereof;
• wherein a curvature radius of an object-side surface of the eighth lens element is R15, a curvature radius of the image-side surface of the eighth lens element is R16, an f-number of the imaging optical lens assembly is Fno, an axial distance between an object-side surface of the first lens element and an image surface is TL, a maximum image height of the imaging optical lens assembly is ImgH, and the following conditions are satisfied:
• −0.50<(R15+R16)/(R15−R16);
• Fno<2.60;
• and
• TL/ImgH<2.0.