Imaging optical lens assembly, image capturing unit and electronic device

An imaging optical lens assembly comprising nine lens elements, 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, and each of the nine lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

• wherein the first lens element has positive refractive power, the ninth lens element has negative refractive power, the object-side surface of the ninth lens element is concave in a paraxial region thereof, and the image-side surface of the ninth lens element is concave in a paraxial region thereof and has at least one inflection point;
• wherein a curvature radius of the object-side surface of the ninth lens element is R17, a curvature radius of the image-side surface of the ninth lens element is R18, a maximum value among central thicknesses of all lens elements of the imaging optical lens assembly is CTmax, a minimum value among central thicknesses of all lens elements of the imaging optical lens assembly is CTmin, and the following conditions are satisfied:
• −0.90<(R17+R18)/(R17−R18)<0.55;
• and
• 1.0<CTmax/CTmin<6.0.

An imaging optical lens assembly comprising three lens groups, the three lens groups being, in order from an object side to an image side along an optical path, a first lens group, a second lens group and a third lens group, the first lens group comprising three lens elements, the second lens group comprising three lens elements, the third lens group comprising three lens elements, and each of all lens elements of the imaging optical lens assembly having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

• wherein the three lens elements of the first lens group comprise a first lens element located closest to the objet side and a second lens element located adjacent to the first lens element on an image side of the first lens element, the first lens element has positive refractive power, and the second lens element has negative refractive power;
• wherein at least one lens surface of at least one lens element of the second lens group has at least one inflection point;
• wherein the three lens elements of the third lens group comprise a last lens element located closest to the image side, and the image-side surface of the last lens element is concave in a paraxial region thereof and has at least one inflection point;
• wherein there is an air lens element located between the last lens element and a lens element located adjacent to the last lens element on an object side of the last lens element, a curvature radius of an object-side surface of the air lens element is Rao, a curvature radius of an image-side surface of the air lens element is Rai, and the following condition is satisfied:
• −25.0<(Rao+Rai)/(Rao−Rai)<10.0.

An electronic device, comprising at least three image capturing units, and the at least three image capturing units comprising:

• a first image capturing unit, comprising a first optical lens assembly and an image sensor disposed on an image surface of the first optical lens assembly, the first optical lens assembly comprising three lens groups, and the three lens groups being, in order from an object side to an image side along an optical path, a first lens group, a second lens group and a third lens group;
• wherein the first lens group comprises at least two lens elements;
• wherein the second lens group comprises at least three lens elements, and at least one lens surface of at least one lens element of the second lens group is aspheric;
• wherein the third lens group comprises at least three lens elements, and at least one lens surface of at least one lens element of the third lens group has at least one inflection point;
• wherein at least four lens elements of the first optical lens assembly are made of plastic material, and half of a maximum field of view of the first optical lens assembly is larger than 35 degrees;
• wherein an Abbe number of one lens element of the first optical lens assembly is Vi, a refractive index of the said one lens element is Ni, a minimum value of Vi/Ni is (Vi/Ni)min, and at least one lens element of the first optical lens assembly satisfies the following condition:
• 7.0<(Vi/Ni)min<11.80;
• a second image capturing unit, comprising a second optical lens assembly and an image sensor disposed on an image surface of the second optical lens assembly, and half of a maximum field of view of the second optical lens assembly being smaller than 25 degrees;
• and
• a third image capturing unit, comprising a third optical lens assembly, a reflector and an image sensor disposed on an image surface of the third optical lens assembly, and half of a maximum field of view of the third optical lens assembly being smaller than 18 degrees.