SMALL-SIZED OPTICAL IMAGING SYSTEM USED FOR CAMERA USING CHARGE COUPLED DEVICE

摘要

PURPOSE: An optical imaging system is provided to reduce the total size and satisfy required optical performance and compensate effectively sensitivity of an image pickup device by using a small number of lenses. CONSTITUTION: An optical imaging system includes an iris(A), a first lens(1), and a second lens(2). The first lens has a positive refractive index. At least one side of the first lens is formed with an aspheric lens. The second lens has a negative refractive index. At least one side of the second lens is formed with an aspheric lens. The image forming lens satisfies the following condition 1.25<LT/f<1.58 where LT is a distance on an optical axis from a target of the iris to an upper face of the iris and f is total focal distance.