Patent ID: 8184387
Filing Date: 2012-05-22
Classification: G02B

Abstract:
1. A miniature optical system comprising: a first lens; a second lens; a third lens; and a fourth lens, wherein the first lens, the second lens, the third lens, and the fourth lens are sequentially aligned from an object side to an image side of the system, and satisfy −1.5<f2/ttl<−0.5, where f2 is a focal length of the second lens and ttl is a distance from the object side of the first lens to the image side of the system; wherein the miniature optical system satisfies 0.2<f1/ttl<0.7, where f1 is a focal length of the first lens; wherein the miniature optical system satisfies 0.7<f3/ttl<1.2, where f3 is a focal length of the third lens; wherein the miniature optical system further satisfies −1.7<f4/ttl<−0.8, where f4 is a focal length of the fourth lens; wherein an image side surface of the second lens and an object side surface of the second lens are both spherical; and wherein a convex surface of the second lens is located at the object side; wherein the first lens and the third lens have positive refractive power, and wherein the second lens and the fourth lens have negative refractive power, wherein a refractive power of the first lens is greater than that of each of the second, third, and fourth lenses, wherein the first lens, the third lens, and the fourth lens comprise plastic material, and wherein the second lens comprises glass material, wherein n2/ttl is greater than n1/ttl, n3/ttl, and n4/ttl, and wherein n1/ttl, n3/ttl, and n4/ttl each have the same value, where n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, and n4 is a refractive index of the fourth lens.