US 12,228,796 B2
Optical imaging system
Jiaying Zhang, Zhejiang (CN); Saifeng Lyu, Zhejiang (CN); Fujian Dai, Zhejiang (CN); and Liefeng Zhao, Zhejiang (CN)
Assigned to ZHEJIANG SUNNY OPTICS CO., LTD., Zhejiang (CN)
Filed by ZHEJIANG SUNNY OPTICS CO., LTD., Zhejiang (CN)
Filed on Feb. 11, 2022, as Appl. No. 17/669,433.
Claims priority of application No. 202110196195.1 (CN), filed on Feb. 22, 2021.
Prior Publication US 2022/0269045 A1, Aug. 25, 2022
Int. Cl. G02B 9/64 (2006.01); G02B 13/00 (2006.01)
CPC G02B 9/64 (2013.01) [G02B 13/0045 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An optical imaging system, sequentially comprising, from an object side to an image side along an optical axis:
a diaphragm;
a first lens with a refractive power, an image-side surface thereof being a convex surface;
a second lens with a refractive power;
a third lens with a negative refractive power;
a fourth lens with a refractive power, an image-side surface thereof being a convex surface;
a fifth lens with a refractive power, an object-side surface thereof being a concave surface;
a sixth lens with a refractive power; and
a seventh lens with a refractive power,
wherein EPD is an entrance pupil diameter of the optical imaging system, and a total effective focal length f of the optical imaging system and the EPD satisfy: f/EPD≤1.5; and
at least one of an object-side surface of the first lens to an image-side surface of the seventh lens is an aspheric surface;
TTL is a distance from the object-side surface of the first lens to an imaging surface of the optical imaging system on the optical axis, and the TTL and a center thickness CT4 of the fourth lens on the optical axis satisfy: 5.5<TTL/CT4<6.5.