Optical design for the lens depth of a periscope-type 3 × zoom lens with 8-megapixel mobile phone

We present an optical design for the lens depth of a periscope-type 3 × zoom lens with 8-megapixel sensor in mobile phone. In the practice application, the lens depth of zoom lens must be less than the thickness of the mobile phone mechanism. The lens depth is thus the upper size limit of the prism thickness or the maximum surface aperture in the Y-direction of the zoom lens. The zoom lens in the designed system has an F-number of F/3.5 to F/5.5, a focal length of 4.514 mm to 13.442 mm, the half field angle in the x-direction is 23.96° to 8.488°, and the half field angle in the y-direction is 14.035° to 4.798°. The smallest lens depth of the zoom lens is 5.377 mm. These results show that the depth of a periscope-type zoom lens can be embedded in the mobile phone.