Description Control apparatus 5 The invention relates to a control apparatus, in particular in a vehicle, having an input unit which has operating keys. Such control apparatuses are known and are frequently used for electrical equipment. For example, 10 in modern motor vehicles, it is normal to use various appliances such as a radio, telephone, air-conditioning system or navigation device. The control panels for these appliances are constructed differently, depending on which of their functions are most frequently 15 required. Thus, for example, the function keys for the volume of the radio have particularly large dimensions and are arranged in a central area of the control panel. A large number of appliances and a large number of functions of these appliances thus lead to the 20 control panels becoming confused- This makes it considerably harder to control the appliances, The lack of clarity in the case of control apparatuses in motor vehicles is particularly disadvantageous since this can result in the vehicle 25 driver's concentration on the traffic being considerably restricted, Attempts have already been made to control all the electrical appliances in a motor vehicle by means of a small number of function keys, by breaking down 30 the functions of the function keys into hierarchical menus and submenus. The functions of the function keys thus change constantly with the menu or submenu. An operator therefore has to read the actual meaning of the keypad in each case, or to have already noted this 35 meaning, before he operates a function key. Such a control apparatus is thus suitable only for controlling a small number of -functions which are required particularly frequently. A further disadvantage of this control apparatus is that the number of function keys -2 and their arrangement are necessarily the same in each menu and submenu, thus making it impossible to arrange the function keys in a manner appropriate for the appliances. However, for simple control demanding only 5 a small amount of attention, it is very helpful to arrange the function keys such that they can be associated directly with the appliances to be controlled. In order to overcome this problem, one object 10 of the present invention is to design a control apparatus of the type mentioned initially so as to ensure that the apparatus can be operated easily and clearly. This object is achieved according to the 15 invention in that the operating keys comprise at least one selection key for defining a device which can be actuated by the control apparatus, and at least one function key, which is associated with the selection key, for actuating the selected device, in which case 20 the function key can be switched to be inactive in a first operating mode, and the function key can be switched to be active in a second operating mode. Thus, in contrast to known devices, it is possible for the operator to switch to the active state 25 only those keys which in each case need to be operated. This precludes distraction resulting from keys which are not required, and possible incorrect operation. Since it is possible, on the control apparatus, to switch to the active state only those function keys of 30 the device which can be actuated and which have been selected by means of a selection key, the control apparatus according to the invention can be interpreted particularly well and with only a brief glance. This is particularly advantageous in the case of a control 35 apparatus which is arranged in a motor vehicle since, in this case, the vehicle driver is distracted only to an insignificant extent from the traffic. A further advantage of the control apparatus according to the -3 invention is that it requires only a particularly small amount of space. In consequence, for example, all the devices which can be actuated and are arranged in a motor vehicle can be operated from a centrally 5 positioned control apparatus according to the invention. Since it is possible to switch to the active state in each case only those function keys which are currently required, this reliably avoids any risk of confusion between different devices which can be 10 actuated. According to one advantageous development of the invention, the operating keys have a control key for controlling a variable of the device which can be actuated. It is thus particularly easy for an operator 15 to use the control apparatus to, for example, set the variable volume of a radio or the variable temperature of an air-conditioning system as well. In this case, the control key may consist, for example, of a rocker key or of two individual keys for increasing or 20 decreasing the variable parameter, or of a single key, whose operation results in the parameter being increased or decreased, in which case, when a minimum or maximum value is reached, a sudden change is then made to the maximum or minimum value, respectively, and 25 in this way it is possible to pass through the entire control spectrum. It is feasible, for example, to use the function key to initiate a defined sequence (such as the starting of a route search by a navigation system), 30 to switch on an appliance such as rear window heating or to check a value, such as the average vehicle fuel consumption calculated by a vehicle computer. On the other hand, it is particularly advantageous if the function key can be used to select a variable parameter 35 for the device which can be actuated. This further improves the clarity of control - particularly when, according to another advantageous development of the invention, the selected parameter can be regulated -4 using the control key. It has been found to be particularly advantageous to be able to use the control key to adjust various parameters for different devices which can be controlled, depending on which function 5 key is operated. Only one control key is thus required to control all the devices. According to another advantageous development of the invention, the operating keys have a changeover key and/or a reset key. It is thus possible, for 10 example, irrespective of the switching of a selection and/or function key, to use the control key in a basic control apparatus mode to regulate a specific parameter for a defined device which can be actuated, for example the volume of an audio system. The changeover key is 15 then used to allow another device to be controlled as a function of the switching of a function key or of a selection key. A reset key is preferably provided in order to make it possible to reset the control apparatus to a predetermined basic mode. 20 It is feasible to arrange the operating keys physically, for example, on the surface of a spherical body. However, it is particularly advantageous for the operating keys to be arranged in a keypad. Such an approximately flat arrangement of the keys in the form 25 of a matrix on the one hand provides a supporting surface for a hand being used to operate the apparatus, and on the other hand ensures that the operator can easily find his way around even after a brief familiarization time, so that the control apparatus can 30 then be operated to a very large extent without any visual contact with the keypad. Since function keys which are not required at any given time are inactive (and cannot be switched to be active), a large supporting surface is available for the hand without 35 this leading to incorrect control operations. The hand which is controlling the apparatus according to the invention can use the supporting surface in which the keypad is located as a rest -5 surface - reducing operator stress - if, according to another advantageous development of the invention, the keypad is arranged approximately horizontally. The operating keys are preferably pushbuttons, 5 so that the operating reliability and the operator friendliness of the apparatus according to the invention are further increased by tactile feedback. A largely flat and protected surface, which withstands environmental influences such as dust and 10 moisture, is advantageously provided if the operating keys form a touch-sensitive keypad. One development of the invention is also particularly advantageous, in which the control key and/or the changeover key and/or the reset key can be 15 switched to be inactive in the first operating mode, and can be switched to be active in the second operating mode. Thus, only those selection keys which are essential at the start of a control process can be switched to be active in any given case in order to 20 define a device which can be actuated, in the first operating mode. Keys which do not necessarily need to be operated in this operating mode are inactive, so that incorrect control operations and incorrect functions are precluded. 25 For example, it would be feasible to change from the first operating mode to the second by means of a voice input by the operator or by means of a separate key. However, the number of keys on the control apparatus is advantageously minimized and the 30 reliability and clarity of the apparatus according to the invention are further increased if the second operating mode can be accessed by switching the selection key. The associated function keys can thus automatically be switched to be active when the 35 appropriate selection key is operated in order to select the device to be actuated. The clarity of the control apparatus is particularly good and the distraction of the operator 6 by information which is not required at that time very poor if, according to another advantageous development of the invention, operating keys which are inactive in the first operating mode cannot be seen in this 5 operating mode. It is particularly advantageous, in particular if the ambient lighting level is low, for it to be possible to illuminate the operating keys so that the operator can identify them easily, and at a first 10 glance, even in a dark environment. If, according to another advantageous development of the invention, operating keys which are inactive in the first operating mode are illuminated with greater brightness in the second operating mode 15 than in the first operating mode, the inactive keys can easily be distinguished from the keys which can be switched to be active. In this case, the inactive operating keys can even be darkened completely, so that they cannot be seen by the operator, particularly if a 20 black panel effect is used. The operator is thus confronted only by keys which he can switch to be active at that particular time. The surface of the control apparatus could be largely flat in all operating modes. However, the keys 25 which can be switched to be active can be detected particularly well by the operator, without any direct visual contact either, if, according to another advantageous development of the invention, operating keys which are inactive in the first operating mode are 30 raised above the surface of the input unit in the second operating mode. The status of the devices which can be actuated can be displayed particularly well, according to another development of the invention, if the control 35 apparatus has a display screen. In this case, it is particularly advantageous if operation of the selection key and/or of the function key can be displayed on the display screen. The display screen thus displays 7 information using which the operator can operate the various devices even more easily. If, in an advantageous manner, the actuation status of the device which can be actuated and is 5 defined by the selection key can be displayed on the display screen, the operator is provided with additional information, which makes it considerably easier to adjust the device as required. In a control apparatus according to the 10 invention which is provided in a motor vehicle, the apparatus can be operated particularly easily if, advantageously, the control apparatus can be arranged in the center console or in the instrument panel of the motor vehicle, so that the apparatus is located within 15 the vehicle driver's immediate access range. In principle, the selection and function keys of the control apparatus according to the invention can be arranged and allocated as required. However, it is particularly advantageous, in particular to make it 20 easy to learn the key arrangement and for reliable operation if, according to another development of the invention, a number of selection keys, which are arranged in an approximately horizontal row, and a number of function keys, which are each associated with 25 a selection key and are each arranged in an approximately vertical column under this selection key, are provided. The control apparatus can be provided for any desired devices which can be actuated, of widely 30 differing types. The high level of clarity of the apparatus and the capability to operate it easily are particularly useful, however, in particular if, according to another advantageous development of the invention, a selection key is in each case provided for 35 control of an air-conditioning system and/or of a vehicle computer and/or of a traffic telematic/navigation system and/or of an audio system in a motor vehicle.
The invention may be configured in widely differing ways. It is explained in more detail in the following text with reference to one exemplary embodiment which is illustrated in the attached 5 drawings, in which: Figure 1 shows a schematic view of an input unit with a keypad of a control apparatus according to the invention, 10 Figure 2 shows the keypad of the apparatus shown in Figure 1 in another operating mode, and Figure 3 shows the keypad of the apparatus shown in 15 Figure 1, with all the keys which are provided. Figure 1 shows a schematic view of an input unit 1 of a control apparatus which has further 20 components, not shown here, such as a housing and electrical contact means. The input unit 1 is fitted in the center console, which is not shown in any more detail, of a motor vehicle. A display screen 2 is arranged in the upper 25 area of the input unit 1, and a keypad 3 is arranged in its lower area. The keypad 3 has four selection keys 4 in an upper, horizontally arranged row, which are respectively designated "VT" for selecting a traffic telematic/navigation system, "A/C" for selecting an 30 air-conditioning system, "BC" for selecting a vehicle computer (on-board computer) and "AUDIO" for selecting an audio system in the motor vehicle. The respectively selected device can be actuated by using the control apparatus. When the control apparatus is in a first 35 operating mode, only the selection keys 4 can be seen in the keypad 3 (see Figure 2) . In a second operating mode which is shown here and which was reached by switching the selection key 4 with the designation -9 "A/C", function keys 5 can be seen, which are arranged in a column vertically under this selection key and by means of which various air-conditioning system functions can be actuated. In the sequence from bottom 5 to top, the function keys 5 allow rear window heating, windshield heating and a fan to be switched on, making it possible to select those air outlet nozzles in a vehicle which are to be used, to switch on an automatic function and a recirculation flap, and to carry out 10 temperature regulation. A control key 10, which has two individual keys 11, 12 can be seen approximately in the center of the keypad 3, which control key 10 allows a variable parameter such as the internal temperature or the fan 15 speed to be adjusted. A changeover key 9 is arranged between the individual keys 11, 12, which are marked "+0 and "-", of the control key 10. This changeover key 9 allows the allocation of the control key 10 to be changed between one predetermined function - for 20 example volume control for an audio system - and a second function which is defined by the function keys 5. Thus, irrespective of which device which can be actuated is being controlled by the control apparatus at a specific time, the volume of the audio system can 25 also always be regulated without having to call up this function separately by switching the appropriate selection and function key. The display screen 2, which is arranged above the keypad 3, has a central display screen area 6, for 30 showing a part of a map from a navigation system, and a lower, horizontal display screen area 8 for displaying general information such as the date, time, internal and external temperature. A left, vertical display screen area 7 displays the inputs made on the keypad 3 35 and the actuation status of the device which can be actuated and is defined by the selection key 4. The present operating mode of the air-conditioning system is thus displayed here, since the selection key 4 with - 10 the designation "A/C" has been operated, and the air conditioning system can be controlled. The keypad 3 from Figure 1 is shown in a first operating mode in Figure 2, in which only the selection 5 keys 4 can be seen by an operator. The associated function keys 5 (see Figure 1) do not appear until one of these selection keys 4 has been selected, and these function keys 5 can then be switched to be active. The same applies to the changeover key 9 and to the control 10 key 10. The keypad 3 is in the form of a touch sensitive keypad, in which background illumination can be provided for the operating keys. Only those keys which are in each case active are in this case 15 illuminated. The surface of the touch-sensitive keypad facing the operator is colored dark gray so that keys which are not illuminated cannot be seen, and this results in a uniform, dark-gray surface (black panel effect). 20 All the keys which are provided on the keypad 3 according to Figure 1 are shown in Figure 3. This figure serves only to illustrate the overall functional scope of the control apparatus and, in contrast, all the keys are never actually presented at the same time 25 in any operating mode. In fact, only those keys which can be selected at the particular time are illuminated and can be seen by the operator.