In recent years, mobile terminal devices such as smart phones, tablets, and smart pads have become electronic devices that people most often come into contact with, carry, and use. Such a mobile terminal is already functionally expanded beyond the function of a landline telephone, which has merely been used for a call, and is now used as a multipurpose device. That is, recent mobile terminals are used as functional devices that provide specific functions according to use purpose of the user, and are also used as amusement equipment that has an important role in the leisure industry.
With this tendency, the functions of the mobile terminal are becoming more complicated and various, and the size of the mobile terminal is becoming larger. As a result, convenience resulting from portability and compactness of the mobile terminal is gradually deteriorating.
In order to solve such inconvenience, the use of an auxiliary terminal that allows some of the functions of the mobile terminal to be performed is increasing.
The auxiliary terminal is generally referred to as a wearable device and is mainly used in a form such as a wristwatch, a spectacle, and a necklace. Especially, the smart watch in a form of a wrist watch is most commonly used among various forms.
Since the smart watch is manufactured in the form of a watch and is used to be worn by the user, the overall shape is frequently exposed to the user as compared with the mobile terminal or other wearable devices, and the exposure time is relatively longer than that of the other devices. Generally, the mobile terminal is stored in a pocket or a bag while moving, whereas the smart watch is used while being worn on the body, whereby the user can frequently check the smart watch, and thus the number of times that the watch is exposed increases and the exposure time thereof is long.
However, even if the auxiliary terminal has excellent design and usability, because the user frequently comes in contact therewith, he/she can become easily bored with the design of the auxiliary terminal. Also, due to the characteristics of mass-produced products, it is difficult for the user to express his/her own characteristics via the watch.