Patent ID: 8023203

Claim:
A miniature three-piece optical imaging lens with short back focal length, along an optical axis thereof from an object side to an image side, comprising: a first lens with positive refractive power that is a meniscus aspherical lens having a convex surface on the object side; an aperture stop; a second lens with negative refractive power that is a meniscus aspherical lens having a convex surface on the image side; and a third lens with negative refractive power on the optical axis that is an aspherical lens whose center is on the optical axis, while on the lens center the convex surface is on the object side and the concave surface is on the image side; from the center of the third lens toward the edge thereof, the refractive power changes from negative power, through an inflection point, to positive power; wherein the optical imaging lens satisfies conditions of: 0.25 ≤ bf TL ≤ 0.4 0.001 ≤ Δ f ≤ 0.006 0.38 ≤ H _ H t ≤ 0.7 ⁢ - 0.12 ≤ f 1 f 2 ≤ - 0.01 ; wherein f is effective focal length of the optical imaging lens, bf is back focal length, TL is total distance on the optical axis from the object side of the first lens to an image plane of an image sensor, Δ is the absolute value of longitudinal chromatic aberrations at Fraunhofer F curve and C curve wavelengths, H is perpendicular distance from the inflection point on the image side of the third lens to its intersection point of the optical axis, H t is perpendicular distance from the maximum optical effective point on the image side of the third lens to the optical axis, f 1 is effective focal length of the first lens, f 2 is effective focal length of the second lens.