Imaging system lens assembly wherein a total number of lens elements is four, imaging apparatus and electronic device

An imaging system lens assembly comprising four lens elements, the four 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 and a fourth lens element;
• each of the four lens elements has an object-side surface towards the object side and an image-side surface towards the image side;
• wherein the second lens element has negative refractive power, the object-side surface of the second lens element is concave in a paraxial region thereof;
• the object-side surface of the third lens element is convex in a paraxial region thereof, the image-side surface of the third lens element is concave in a paraxial region thereof;
• wherein a total number of the lens elements of the imaging system lens assembly is four;
• there is an air gap between each of adjacent lens elements of the four lens elements of the imaging system lens assembly;
• the imaging system lens assembly further comprises an aperture stop, an axial distance between the aperture stop and the image-side surface of the fourth lens element is SD, a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, an axial distance between the object-side surface of the first lens element and the image-side surface of the fourth lens element is TD, an axial distance between the image-side surface of the fourth lens element and an image surface is BL, an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, a central thickness of the first lens element is CT1, a central thickness of the third lens element is CT3, a central thickness of the fourth lens element is CT4, and the following conditions are satisfied:
• (R3+R4)/(R3−R4)<0;
• 0.1<SD/TD<2.0;
• 0.1<TD/BL<1.0;
• 0.01<T23/T12<30.0;
• 0<|f2/f4|<0.95;
• and
• 0.1<(CT3+CT4)/CT1<1.5.

An imaging system lens assembly comprising four lens elements, the four 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 and a fourth lens element;
• each of the four lens elements has an object-side surface towards the object side and an image-side surface towards the image side;
• wherein the second lens element has negative refractive power, the object-side surface of the second lens element is concave in a paraxial region thereof;
• the object-side surface of the third lens element is convex in a paraxial region thereof, the image-side surface of the third lens element is concave in a paraxial region thereof;
• wherein a total number of the lens elements of the imaging system lens assembly is four;
• a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, an axial distance between the object-side surface of the first lens element and the image-side surface of the fourth lens element is TD, an axial distance between the image-side surface of the fourth lens element and an image surface is BL, an axial distance between the first lens element and the second lens element is T12, an axial distance between the second lens element and the third lens element is T23, a focal length of the imaging system lens assembly is f, a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, and the following conditions are satisfied:
• (R3+R4)/(R3−R4)<0;
• 0.1<TD/BL<1.0;
• 0.01<T23/T12<20.0;
• −10.5<f/f2<−0.75;
• and
• 0<|f1/f4|<0.87.