Abstract: A terminal unit (400) of a navigation system (100) transmits to a server (300) list request information containing a rectangular code corresponding to a predetermined display rectangular area of a travel route map. The terminal unit (400) acquires from the server (300) a server POI list corresponding to the rectangular code of the list request information, and when recognizing that the server POI list contains POI individual information corresponding to terminal base data that is not stored in a terminal base storage area, the terminal unit (400) transmits base data request information about POIID of the POI individual information to the server (300). Upon acquisition of server base data corresponding to the base data request information from the server (300), the terminal unit (400) stores the server base data in the terminal base storage area as terminal base data.

Abstract: A map distribution system, includes an information center that stores the latest map information and a terminal device including a communication unit, a map storing unit, and a control information storing unit. The communication unit transmits information to the information center and receives information from the information center. The map storing unit stores map information. The control information storing unit stores control information associated with the map information. The terminal device transmits the control information to the information center every prescribed timings. The information center transmits the latest control information to the terminal device in response to the transmitted control information. The terminal device rewrites the control information stored in the control information storing unit to the latest control information.

Abstract: An upgrade method for navigation data is provided with: a memory status of a memory device that is removed from a navigation apparatus is checked and it is determined whether there are the navigation data to be upgraded and the user data to be saved. The user data is saved in a backup memory device. The navigation data is written over with upgraded navigation data. Then, the saved data is read from the backup memory device and rewritten in the memory device as the user data.

Abstract: A terminal unit (400) of a navigation system (100) transmits to a server (300) list request information containing a rectangular code corresponding to a predetermined display rectangular area of a travel route map. The terminal unit (400) acquires from the server (300) a server POI list corresponding to the rectangular code of the list request information, and when recognizing that the server POI list contains POI individual information corresponding to terminal base data that is not stored in a terminal base storage area, the terminal unit (400) transmits base data request information about POIID of the POI individual information to the server (300). Upon acquisition of server base data corresponding to the base data request information from the server (300), the terminal unit (400) stores the server base data in the terminal base storage area as terminal base data.

Abstract: A map distribution system, includes an information center that stores the latest map information and a terminal device including a communication unit, a map storing unit, and a map storing unit. The communication unit transmits information to the information center and receives information from the information center. The map storing unit stores map information. The control information storing unit stores control information associated with the map information. The terminal device transmits the control information to the information center every prescribed timings. The information center transmits the latest control information to the terminal device in response to the transmitted control information. The terminal device rewrites the control information stored in the control information storing unit to the latest control information.

Abstract: A communication navigation system is provided with a communication center apparatus (3x) and a communication terminal apparatus (5x) for transmitting/receiving information via a communication network (1x). The communication center apparatus includes a database (302) for storing data to be updated to the latest version, and a center side controlling device (301) for transmitting data in response to an updating request. The communication terminal apparatus includes a saving device (503) for saving data and the corresponding time and date information indicating the saving time and date of the data, and a terminal side controlling device for transmitting the updating request for transmitting the data over a predetermined period starting from the saving time and date, and updating the data by means of data transmitted in response to the updating request.

Abstract: An upgrade method for navigation data is provided with: a memory status of a memory device that is removed from a navigation apparatus is checked and it is determined whether there are the navigation data to be upgraded and the user data to be saved. The user data is saved in a backup memory device. The navigation data is written over with upgraded navigation data. Then, the saved data is read from the backup memory device and rewritten in the memory device as the user data.

Abstract: A reflection mirror of a projection display unit which displays a stereoscopic image through a light polarization glasses, reflects a linearly polarized light emitted from a projection source through a polarizing plate toward a screen. The reflection mirror includes: a glass substrate; a metal film provided on the glass substrate; a first dielectric film provided on the metal film; and a second dielectric film provided on the first dielectric film, wherein each of the first and second dielectric films includes a predetermined thickness and a predetermined refractive index so that a phase difference between a p-polarized light of a reflected light and a s-polarized light of the reflected light is within a range from -45 degree to 45 degree in case of an incident angle of the linearly polarized light being varied from 0 degree to 45 degree.