A composite armor element for protection against projectiles. The terminal displays telephone number display screen data received form the server apparatus, and transmits, to the server apparatus, designation information indicating a telephone number position in the display screen, which is designated by a user. The bulb is transparent to visible light and infrared radiation emitted by the plasma. A third encryption processing portion decrypts the encrypted content data read from memory card with the license key to reproduce content data. By diffusing an error value, which is a difference between the grayscale level and the determined binary value of the input pixel, to neighboring pixels, the grayscale level of the neighboring pixels is changed.