Information retrieval and display systems

摘要

In an information retrieval and display system, an interface unit 32 receives signals from a hand-held user control unit 34, for example joystick 38, and controls the information displayed on a display 30 in response thereto. Each control signal from the hand-held unit 34 is generated by a single operator action, that is, movement of the joystick 38 in a given direction. The information available for display is arranged in a tree structure. The interface unit 32 is arranged to scroll through the currently displayed information in a first direction at a speed related to the displacement of the joystick 38 in a first (up) direction, to scroll through the currently displayed information in the opposite direction at a speed related to the displacement of the joystick 38 in a second, opposite (down) direction, to display information from a lower level in the tree in response to movement of the joystick in a third (right) direction, and to display information from a higher level in the tree in response to movement of the joystick in a fourth (left) direction.