US 12,481,128 B2
Optical imaging system, image capturing unit and electronic device
Yu-Tai Tseng, Taichung (TW); and Hsin-Hsuan Huang, Taichung (TW)
Assigned to LARGAN PRECISION CO., LTD., Taichung (TW)
Filed by LARGAN PRECISION CO., LTD., Taichung (TW)
Filed on Mar. 11, 2022, as Appl. No. 17/693,033.
Application 17/693,033 is a continuation of application No. 16/421,272, filed on May 23, 2019, granted, now 11,307,385.
Claims priority of application No. 108110521 (TW), filed on Mar. 26, 2019.
Prior Publication US 2022/0196973 A1, Jun. 23, 2022
Int. Cl. G02B 13/00 (2006.01); G02B 9/34 (2006.01); G02B 9/58 (2006.01)
CPC G02B 13/004 (2013.01) [G02B 9/34 (2013.01); G02B 9/58 (2013.01)] 30 Claims
OG exemplary drawing
 
1. An optical imaging system comprising four lens elements, the four lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element; each of the four 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 negative refractive power, the object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof, the object-side surface of the first lens element is aspheric, the third lens element has positive refractive power, the fourth lens element has negative refractive power, and a total number of lens elements in the optical imaging system is four;
wherein the optical imaging system further comprises an aperture stop, an axial distance between the object-side surface of the first lens element and an image surface is TL, a focal length of the optical imaging system is f, an axial distance between the aperture stop and the image-side surface of the fourth lens element is SD, 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 Abbe number of the fourth lens element is V4, and the following conditions are satisfied:

OG Complex Work Unit Math