Patent ID: 11880048
Assignee: LARGAN PRECISION CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An imaging lens assembly comprising five lens elements, the five lens elements being, in order from an object side to an image side:
a first lens element having positive refractive power;
a second lens element;
a third lens element having an object-side surface being concave in a paraxial region thereof;
a fourth lens element having an image-side surface being concave in a paraxial region thereof; and
a fifth lens element having an image-side surface being concave in a paraxial region thereof, wherein an object-side surface and the image-side surface of the fifth lens element are both aspheric, and the image-side surface of the fifth lens element comprises at least one convex critical point in an off-axis region thereof;
wherein a total number of lens elements in the imaging lens assembly is five, a focal length of the second lens element and a focal length of the third lens element have different signs, a curvature radius of an object-side surface of the second lens element is R3, a curvature radius of an image-side surface of the second lens element is R4, a curvature radius of an object-side surface of the fourth lens element is R7, a curvature radius of the image-side surface of the fourth lens element is R8, a focal length of the imaging lens assembly is f, a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, and the following conditions are satisfied:

(|R7|+|R8|)/f<1.50;

−2.0<f4/f5<−0.75; and

0.75<(R3+R4)/(R3−R4)<4.0.