Patent ID: 7154681
Filing Date: 2006-12-26
Classification: G02B

Abstract:
1. A subminiature optical system having an aperture stop arranged closest to an object side, comprising, sequentially from the object side: a first lens group having a first lens of plus refractive power and a second lens of minus refractive power, the second lens being cemented to the first lens; a second lens group having a third lens where at least one refraction surface is aspherical and has minus refractive power; and a third lens group having a fourth lens where at least one refraction surface is aspherical and has minus refractive power, in which a refractive power of the first lens group satisfies the following Equation 1 and a dimension of an optical axis direction in the whole lens system satisfies the following Equation 2; where f f: composite focal length of the whole lens system TL: distance from the aperture stop up to an image plane.