Patent ID: 7289278
Filing Date: 2007-10-30
Classification: G02B

Abstract:
1. A subminiature imaging optical system comprising: an aperture stop; a first lens having a positive refractive power and being convex at an object side; a second lens having a negative refractive power; a third lens having a positive refractive power; and a fourth lens having a negative refractive power, wherein the optical system has a total length along an optical axis direction according to following relation 1, the first and second lenses have an abbe number according to following relation 2, and the first and second lenses have a refractive index according to following relation 3: where TL is a distance from the aperture stop to an image plane, f is an effective focal distance of an entire optical system, Vd1 is an abbe number of the first lens, Vd2 is an abbe number of the second lens, Nd1 is a refractive index of the first lens, and Nd2 is a refractive index of the second lens.