Terminals may be classified into mobile/portable terminals and stationary terminals depending on the mobility. The mobile terminals may be classified into handheld terminals and vehicle mount terminals according to direct portability by a user.
Functions of the mobile terminals become diversified. The functions of the mobile terminals include data and voice communication, picture capturing and video recording through a camera, voice recording, a music file playback through a speaker system, and image or video output to a display unit. Some terminals further include an electronic game play function or perform a multimedia player function. In particular, recent mobile terminals may receive multicast signals providing visual content such as broadcasts and video or television programs.
The mobile terminals are mostly held in the hands and are used by a user, and furthermore, may be expanded to wearable devices which may be worn on the body of the user. Examples of such a wearable device include a watch-type mobile terminal, a glass-type mobile terminal, a head mounted display (HMD), and the like.
Among the mobile terminals, the watch-type mobile terminal is a mobile terminal in which an electronic function, a communication function, a multimedia function, and the like are added to a watch always worn by people. Since the watch-type mobile terminal does not cause negative feeling to people, it appears that the market for the watch-type mobile terminal is explosively created in the future.
Therefore, a research, a development, and commercialization of the watch-type mobile terminal are actively conducted.