The Optic And Mechanical Design Of External Telescope For Mobile Phone

External telescopic lens for Mobile phone bring great convenience and fun to people’s life. Mobile phone has been a popular thing in life because of its many functions except making a call, such as camera, recorder, and so on. In fact, it has replaced normal digital camera gradually due to its high quality device, for example, CMOS and its lens. But it is difficult to catch a photo of a long distance object, comparing the normal digital camera as its lens is specially designed for conditional object instead of a long distance object. We have already designed and made an external wide angle lens for mobile phone successfully.This paper introduces three kinds of external telescope for mobile phone. The first one is a detachable external telescope. The external telescope system is designed to work with the mobile phone’s own lens. It can be used to observe and take a photo of long distance object directly, even for the surface of the moon.The second one and the third one are the design of the 12 times and 30 times external telescope for mobile phone. There are many uses in life. They are used to film the object that far or not easy to close. The telescope drawtube could connect with mobile phone easy and portable. Its strict spherochromatic aberration correction makes the image quality correction more excellent. The lens diameter is 60 mm to ensure the light, bright image. The focal length of its eyepiece lens is f=25 mm or f=10 mm. The telescope system has a focal length of 1000 mm. It is not only enough to ensure high resolution imaging and but also to obtain higher multiples. Combining with the lens in mobile phone, image from a long distance, e.g. moon surface, can get clearly. In the mechanical structure, the length of the system along the axial is about 750 mm. In order to facilitate carrying, the telescope tube is designed to be detachable structure of two part, which can be connected by a fastener immediately. Its objective lens uses doublet structure. The mechanical structure of eyepiece is designed reasonably to ensure that the system and mobile phone lens are coaxial and can be connect quickly. It is an external accessary for the mobile phone to make the mobile phone more powerful. The system was designed for two kind of usage: one is the observation by human eye with a special lens in telescope, another is recording the image by the camera in the mobile phone simultaneously. After optimization of design, this moon telescope system has small size, light weight, easy to carry.