Abstract:
A display device, especially for a motor vehicle, includes a display unit a display controller and at least one control unit, with which the image format of the display unit can be controlled. The display unit is configured such that it can be moved to enable different display fields to be viewed.

Description:
This application is a Continuation of: PCT/EP00/04812 filed May 26, 2000, incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a display device, especially for a motor vehicle, wherein the image displayed can be varied. 
     Display devices are known, for example for displaying the digital street maps of a navigation system. Here the display unit, which is designed for example as an LCD or a monitor, is operated by means of a display controller, which continuously changes the representation on the display unit as a function of current position. Moreover, the display controller changes the image format on the display unit as necessary depending on commands entered through input control. Since the available installation space is limited, especially in motor vehicles, repeated efforts have been made to allocate multiple convenience systems to an existing display device, so that the information from various systems can be displayed as needed. Using a menu, for example, the user can select a system whose information is displayed generally in the form of another menu. As is known from the computer field the information and input options that are offered are organized hierarchically in sub-menus. A disadvantage of the known display devices is that the user can easily lose track of where he is currently located in the menu system. Another disadvantage arises when the user wishes to switch between individual displays, since the superposition of multiple menus known from the computer field can be used only to a limited extent because of the size of the display unit. 
     It is an object of the invention to provide an improved display system for providing alternate display images. 
     SUMMARY OF THE INVENTION 
     As a result of a movable image format on the display unit, or a movable display unit with a visual field delimitation, where the entire display unit can be used to present information, the display device can be associated with several systems at once, where only the information for one system is presented on the display unit at any one time. 
     The movable display device can be moved either directly through a manual mechanical transmission of force and/or indirectly through a control unit. In the case of indirect movement, the input commands that are entered via the control unit are converted into control signals for actuators, for example for stepper motors. 
     In a preferred embodiment, the display unit is designed as a hemispherical or spherical shell, by which means a large display area on a spherical surface is achieved in a small installation space. 
     In another preferred embodiment, a stop is associated with the display unit for each direction of motion, so that the display unit can be returned to a base setting by means of a spring return device. 
     The control unit is preferably designed as a trackball and/or as a joystick, where motion control of the display unit, in the form of a hemispherical or spherical shell, is very simple, especially with a trackball. In principle, the input unit can also be designed as a pushbutton or rocker switch. 
     The display unit is preferably designed as a touch screen, whose touch-sensitive fields form a control unit that can be used to input movement commands as well as data and control commands. 
     In a further preferred embodiment, the display device is integrated into a steering device of a motor vehicle, so that a vehicle driver has the display unit in his direct field of view. Depending on the form of the display unit, it may be necessary to modify the steering device to accommodate the display unit for this purpose. It is advantageous for this purpose to design the steering device as a steer-by-wire system. The advantage of steer-by-wire systems, as for example per U.S. Pat. No. 5,237,441 or DE 42 15 630 A1, is that the centrally located steering linkage is eliminated, which significantly simplifies the integration of spherical display units in particular. 
     The invention is described in detail below using example embodiments. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a schematic block diagram of a display device with movable image format in a base position. 
     FIG. 2 is a schematic block diagram of the display device of FIG. 1 in a second position. 
     FIG. 3 is a perspective view of a spherical display unit. 
     FIG. 4 shows a field of view of the display unit per FIG. 3 in a base position. 
     FIG. 5 shows a field of view of the FIG. 3 display unit in a second position. 
     FIG. 6 shows the field of view of FIG. 5 after entry of a command. 
     FIG. 7 is a perspective view of a steering device to accommodate a display unit. 
    
    
     DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1 display unit  1  comprises a display device  2 , a control unit  3 , a display controller  4 , a multiplexer  5  and four convenience systems S 1 -S 4 . The control unit  3  is connected to the display controller  4 , which is bidirectionally connected to the four convenience systems S 1 -S 4 . The display controller  4  is connected to the display unit  2  through the multiplexer  5  and controls the image format on the display unit  2 , which may be an LCD display or monitor, for example. Both movement commands and control commands for the convenience systems S 1 -S 4  may be entered via the control unit  3 . 
     The image formats for all four convenience systems S 1 -S 4  are generated independently of one another, and each can be displayed individually in a corresponding display field. In a base position G, the display controller  4  supplies a corresponding image format to the display unit  2  through the multiplexer  5 . This image format displays for convenience systems S 1 -S 4  can be separately called for and displayed by the display unit  2 . For this purpose, a direction of motion may be associated with each image format of a convenience system S 1 -S 4 . For example, if a motion “to the right” is entered via the control unit  3 , this is received by the display controller  4  and converted into a control command for the multiplexer  5 . This control command is transmitted to the multiplexer  5  through a control line  6 , so that the image format of convenience system S 2  is now presented on the display unit  2 , as is shown in FIG.  2 . In this way, the individual image formats of the four convenience systems S 1 -S 4  are conceptually arranged around the display unit  2  and can be moved into the display unit  2  by means of the control unit  3 . Hence, in this arrangement, the display unit  2  remains spatially fixed in place, and the image format to be displayed is moved via the control unit  3 . 
     Alternatively, the display unit  2  itself can be moved. In this case, it is assumed that the display area is of cruciform design, where the image formats for all four convenience systems S 1 -S 4  and the base position can be displayed simultaneously on the display unit. In this case, the display unit  2  is associated with a housing having a transparent opening that defines a field of view the size of an image data display format. Since all image formats are displayed in parallel, the multiplexer  5  is not required. There is a positioning device by means of which the display unit can be moved relative to the housing, so that the desired image data display can be moved into the field of view. However, in a planar design of the display unit, a correspondingly greater installation space is needed, which does not satisfy the prerequisites in a motor vehicle. 
     FIG. 3 shows a display unit  2  designed as a spherical shell. The spherical shell is designed with an opening through which electrical lines can pass into the interior of the spherical shell. In contrast to a planar design, the area of the display unit can be implemented with a compact construction with a spherical shell. The spherical shell is then arranged in the instrument panel, for example, and the image projected on the spherical shell is moved or rotated, wherein the rotatability can also be restricted to specific axes. By means of the lateral delimitation in the installation location, or by means of a display housing, the field of view on the spherical shell is limited to a segment of a sphere, defined by a transparent opening in the housing, so that for example a display as shown in FIG. 4 results. The motion or rotation is accomplished, for example, by an electrical positioning system that receives its control commands via an control unit  3 . In this case, the control unit  3  is preferably adapted to the motions that are to be performed. If the motion is limited to two axes, the control unit  3  can be designed as a four-way pushbutton switch or rocker switch. Control unit  3  may also comprise touch sensitive portions of the display  2 . In the case of possible rotations about multiple axes, trackballs or joystick-like controls are used advantageously. 
     FIG. 4 shows the display unit  2  in a base position. The image format in the field of view includes four display fields  7  in the form of segments of a circle, each of which is associated with a convenience system. Each display field  7  has associated with it a pictogram-shaped arrow  8  from which is derived the direction of motion for the image format of the associated convenience system. Moreover, a semicircular indicator scale  9 , for example for vehicle speed, is located above the display fields  7 . If the user wishes to see the image format for the navigation system in the field of view, the spherical shell must be rotated downwards, as the larger arrow is intended to indicate. In this regard, a threshold torque can be associated with each direction of rotation, where the spherical shell rotates through a fixed angle once this torque is exceeded, so that the display field located in the direction of rotation is fully displayed in the field of view. 
     Once rotation in the direction of the arrow is completed, an image format for the navigation system appears, as shown in FIG.  5 . The indicator scale  9  can be permanently associated with each image format, so that it is always visible in the same position in the field of view regardless of which image format has been selected. When the display unit is designed as a touch screen, input positions over touch-sensitive fields  10  can be displayed in a visually highlighted manner. In the example shown, the user is asked whether an alternate route should be calculated. Now if the touch-sensitive field  10  is touched or the command is entered via another control unit, the alternate route is calculated and displayed in accordance with FIG.  6 . If the user now wishes to switch from the navigation system to the entertainment system, the spherical shell is first rotated upward again and is then rotated to the left. In addition, each direction of motion can be associated with a stop having a return device. In the example as shown in FIG. 6, a further downward rotation would cause the spherical shell to be rotated back to the position shown in FIG.  4 . 
     FIG. 7 shows a perspective view of a steering device  11  to accommodate a display unit  2  in the form of a spherical shell. The steering device  11  includes a steering wheel  12 , a base body  13  in the form of a spherical shell, steering angle sensors  14  and mechanical fastening devices  15 . The base body  13  in the form of a spherical shell has an opening in the vicinity of the steering wheel  12  that is surrounded by a ridge-shaped border  16 . The spherical-shell-shaped display unit  2  is rotatably arranged within the base body  13 , where the opening and the border  16  form a transparent opening. The supply cables and control lines for the display unit  2  pass into the base body  3  through a cable feedthrough  17 . 
     While there have been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further changes can be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the true scope of the invention.