Optical imaging lens

An optical imaging lens, sequentially comprising a first lens element, a second lens element, a third lens element, and a fourth lens element along an optical axis from an object side to an image side, wherein each of the first lens element to the fourth lens element comprises an object-side surface facing the object side and allowing imaging rays to pass through, and an image-side surface facing the image side and allowing the imaging rays to pass through;

• the first lens element has negative refracting power, an optical axis region of the object-side surface of the first lens element is convex, and an optical axis region of the image-side surface of the first lens element is concave;
• the second lens element has positive refracting power;
• and
• an optical axis region of the image-side surface of the fourth lens element is convex;
• wherein
• lens elements of the optical imaging lens are only the four lens elements, and the optical imaging lens further satisfies following conditional expressions:
• BFL/AAG≥2.400, 2.200≤T4/G12≤4.500 and HFOV/TTL≥15.000 degrees/mm, where BFL is a distance from the image-side surface of the fourth lens element to an image plane on the optical axis, AAG is a sum of three air gaps from the first lens element to the fourth lens element on the optical axis, T4 is a thickness of the fourth lens element on the optical axis, G12 is an air gap between the first lens element and the second lens element on the optical axis, HFOV is a half field of view of the optical imaging lens, and TTL is a distance from the object-side surface of the first lens element to the image plane on the optical axis.

An optical imaging lens, sequentially comprising a first lens element, a second lens element, a third lens element, and a fourth lens element along an optical axis from an object side to an image side, wherein each of the first lens element to the fourth lens element comprises an object-side surface facing the object side and allowing imaging rays to pass through, and an image-side surface facing the image side and allowing the imaging rays to pass through;

• a periphery region of the image-side surface of the first lens element is concave;
• an optical axis region of the image-side surface of the third lens element is concave;
• and
• a periphery region of the object-side surface of the fourth lens element is concave;
• wherein
• lens elements of the optical imaging lens are only the four lens elements, and the optical imaging lens further satisfies following conditional expressions:
• BFL/AAG≥2.400, ImgH/(G12+G23)≥2.400 and HFOV/TTL≥15.000 degrees/mm, where BFL is a distance from the image-side surface of the fourth lens element to an image plane on the optical axis, AAG is a sum of three air gaps from the first lens element to the fourth lens element on the optical axis, ImgH is an image height of the optical imaging lens, G12 is an air gap between the first lens element and the second lens element on the optical axis, G23 is an air gap between the second lens element and the third lens element on the optical axis, HFOV is a half field of view of the optical imaging lens, and TTL is a distance from the object-side surface of the first lens element to the image plane on the optical axis.