US 11,656,430 B2
Optical imaging system
Jianke Wenren, Ningbo (CN); Xule Kong, Ningbo (CN); Mengna Tang, Ningbo (CN); Fujian Dai, Ningbo (CN); and Liefeng Zhao, Ningbo (CN)
Assigned to Zhejiang Sunny Optical Co., Ltd, Ningbo (CN)
Filed by Zhejiang Sunny Optical Co., Ltd, Ningbo (CN)
Filed on Aug. 31, 2020, as Appl. No. 17/7,083.
Claims priority of application No. 201910841177.7 (CN), filed on Sep. 6, 2019.
Prior Publication US 2021/0072499 A1, Mar. 11, 2021
Int. Cl. G02B 9/34 (2006.01); G02B 13/00 (2006.01); G02B 13/18 (2006.01)
CPC G02B 9/34 (2013.01) [G02B 13/004 (2013.01); G02B 13/18 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical imaging system, sequentially from an object side to an image side of the optical imaging system along an optical axis, comprising:
a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power; and
a fourth lens having negative refractive power,
wherein 1<TTL/To<2.5,
where TTL is a distance along the optical axis from an object-side surface of the first lens to an imaging plane of the optical imaging system, and To is a distance along the optical axis from a to-be-captured object to the object-side surface of the first lens.