US Patent 11366288 Optical imaging system

An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially disposed in numerical order along an optical axis of the optical imaging system from an object side of the optical imaging system toward an imaging plane of the optical imaging system, wherein the optical imaging system satisfies 1<|f123457−f|/f, where f123457 is a composite focal length of the first to seventh lenses calculated with an index of refraction of the sixth lens set to 1.0, f is an overall focal length of the optical imaging system, and f123457 and f are expressed in a same unit of measurement.