US 12,013,592 B2
Optical imaging system including eight lenses of ++−+−+−− or ++−+−++− refractive powers
Jung Hui Ko, Suwon-si (KR); and Yong Joo Jo, Suwon-si (KR)
Assigned to Samsung Electro-Mechanics Co., Ltd., Suwon-si (KR)
Filed by Samsung Electro-Mechanics Co., Ltd., Suwon-si (KR)
Filed on Jul. 29, 2022, as Appl. No. 17/877,276.
Application 17/877,276 is a continuation of application No. 16/658,244, filed on Oct. 21, 2019, granted, now 11,435,557.
Claims priority of application No. 10-2019-0055680 (KR), filed on May 13, 2019.
Prior Publication US 2022/0373770 A1, Nov. 24, 2022
Int. Cl. G02B 9/64 (2006.01); G02B 13/00 (2006.01)
CPC G02B 9/64 (2013.01) [G02B 13/0045 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An optical imaging system comprising:
a first lens having positive refractive power, a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power, a sixth lens having refractive power, a seventh lens having positive or negative refractive power, and an eighth lens having negative refractive power, which are sequentially arranged from an object side of the optical imaging system,
wherein at least three of the lenses have negative refractive power with a refractive index greater than 1.66,
wherein TTL/(2*IMG HT)<0.9, where TTL is an optical axis distance from an object-side surface of the first lens to an image capturing surface of an image sensor, and IMG HT is half of a diagonal length of the image capturing surface of the image sensor, and
wherein f/EPD<1.5, where f is an overall focal length of an imaging system including the lenses, and EPD is a diameter of an entrance pupil.