Patent ID: 7742240

Claim:
A subminiature imaging optical system comprising, sequentially from an object side: a first lens having a meniscus shape with a convex object-side surface, the first lens having at least one aspherical surface and positive refractive power; a second lens having a meniscus shape with a convex image-side surface, the second lens having a spherical surface and negative refractive power; and a third lens having both surfaces formed of an aspherical surface and having positive refractive power, wherein the first lens satisfies following condition 1 and the third lens satisfies following conditions 2 and 3: 0.4 <f 1 /f< 0.8 condition 1, 1.4 <T max/ T min<3.0 condition 2, 1.5 <f 3 /f< 5.0 condition 3, where f is an effective focal length of the optical system, f 1 is a focal length of the first lens, Tmax is a maximum thickness of the third lens within an effective aperture, Tmin is a minimum thickness of the third lens within an effective aperture and f 3 is a focal length of the third lens.