Control device for an electrical appliance and electrical appliance

Abstract

A control unit for a cooktop comprises a control panel and a capacitive touchscreen for operation by placing a finger on it. The touchscreen features a display, a user interface, and capacitive sensor elements distributed across its surface. The control unit includes a control element that is movable and removable on the user interface and is designed in two parts: a lower and an upper part that can be rotated relative to each other about a vertical axis. The control element has sensors for detecting rotation between the lower and upper parts and a radio transmitter for wirelessly transmitting signals to a corresponding radio transmitter on the control unit. The radio transmitter then transmits information detecting the rotation to the control unit's controller via the corresponding radio transmitter.The control unit is designed to use capacitive sensors to detect the position of the control element on the user interface and to adjust a display around the control element accordingly, as well as to trigger operating commands.

Description

Application area and state of the art

[0001] The invention relates to a control device for an electrical appliance, which is advantageously a household appliance such as a cooktop, wherein the control device comprises, on the one hand, a touchscreen for operation with a finger and, on the other hand, a rotatable control element. Furthermore, the invention relates to an electrical appliance with such a control device, in particular a household appliance.

[0002] Touchscreen operating devices are known from the prior art, see for example DE 102006039235 A1. These allow a single operator to conveniently display a large amount of information and simultaneously a large number of individual and / or detailed operating options.

[0003] Operating devices with a different operating philosophy feature removable and rotatable control elements on a user interface; see, for example, DE 102012213693 A1. A rotatable control element allows for operation similar to a conventional stove with mechanically operated rotary knobs. Task and solution

[0004] The invention is based on the objective of creating an operating device as mentioned above and an electrical device equipped with it, with which problems of the prior art can be solved and in particular it is possible to design an operating device in a practical manner and thus to operate an electrical device advantageously and with many options.

[0005] This problem is solved by an operating device with the features of claim 1 and by an electrical device with such an operating device having the features of claim 12. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features are described only for the operating device or only for the electrical device. However, they should be able to apply independently and autonomously to both such an operating device and such an electrical device. The wording of the claims is incorporated into the description by express reference.

[0006] The operating device for the electrical appliance comprises a controller, in particular a microcontroller, and a flat, capacitive touchscreen. This touchscreen can be operated, as is known per se, by placing and / or moving a finger on it. The touchscreen has a display, preferably a TFT display, a user interface for placing a finger, and capacitive sensor elements beneath this user interface. These sensor elements can be positioned above the display, so that the user interface can advantageously be formed by a glass panel. The aforementioned controller can be used to evaluate the touchscreen; it may also perform other control functions or all control functions for the electrical appliance.

[0007] The operating device has at least one control element that is movable and removable on the user surface. In particular, the control element can also be placed at any point on the operating device or on the user surface and then operated there as intended. This control element is designed in two parts: a lower part and an upper part, which can be rotated relative to each other. This rotation occurs around an axis of rotation that runs vertically to the user surface on which the control element is mounted. Such a control element can therefore be used similarly to known rotatable control elements, except that the upper part can be rotated. The lower part rests fixedly on the user surface without rotation, so that operation depends on a rotation or rotational position between the lower and upper parts. These can be designed in different ways, as will be explained in detail later.Furthermore, the control element includes a radio device or other means for wirelessly transmitting signals to the operating unit, which in turn has a corresponding radio device. Thus, the signals detected by the aforementioned sensor means regarding rotation and / or position can be transmitted to the operating unit or its control system. This information is then used to operate the electrical device equipped with the operating unit or to trigger its functions. The radio device and the corresponding radio device can advantageously be designed as described in the prior art and utilize known methods, such as Bluetooth or BLE, ZigBee, or other radio standards.

[0008] The aforementioned capacitive sensor elements are distributed across the entire surface of the touchscreen, and in particular, evenly distributed. This allows for versatile and freely configurable operation via the touchscreen or the control unit. Furthermore, the control unit is designed to use these capacitive sensor elements to detect the position of the control unit on the user surface. This position can be detected generally, in order to enable operation based on corresponding radio signals from the control unit. It can also be designed so that placing the control unit anywhere other than on the control unit or its user surface is ignored, even if the receiving radio device receives corresponding signals and information from the control unit. In such a case, operation would be considered improper.Furthermore, this allows the specific position of the control element on the user interface to have a particular effect. For example, on a cooktop with multiple cooking zones, only one cooking zone can be controlled by a single control or command, and its position on the cooktop corresponds to the relative position of the control element on the user interface. Additionally, this allows a specific display to be adapted or changed on or around the control element. Thus, the display around the control element can remain essentially the same, or be structured according to the same principles, regardless of the specific location where the control element is placed on the user interface.

[0009] By using a freely positionable control element on the user interface, which is rotatable and can be advantageously placed in different positions for operation, a very high degree of freedom is provided for operation and the design of an operating concept. Furthermore, a specific operating function or the provision of specific information can be achieved or conveyed simply by choosing a specific location on the user interface where the control element is placed.

[0010] In an advantageous embodiment of the invention, the control element can have a rotary bearing as a support for the upper part on the lower part, with the lower part resting on the operating surface. Such a rotary bearing can be annular and absorb vertical as well as horizontal bearing forces. This allows the upper part to rotate smoothly relative to the lower part, resulting in greater ease of use and higher operating accuracy. For this purpose, the rotary bearing can, for example, be designed as a ball bearing; reference is made to DE 102012213693 A1. The diameter of the rotary bearing can be between 40% and 90%, and in particular between 50% and 75%, of the diameter of the control element.

[0011] The aforementioned sensor means for detecting rotation and / or rotational position are advantageously provided between the lower and upper parts, particularly advantageously closer to the underside of the control element than to the upper side. They can be positioned close to the aforementioned radio device, so that the distance to the aforementioned receiving radio device of the control unit is not as long, thus reducing the power required for the radio signals and thereby lowering energy consumption. One possible embodiment for such sensor means is that they are magnetically operated. For this purpose, at least one magnet and at least one magnetic field sensor can be provided. Due to its electrical connections, the magnetic field sensor is advantageously arranged on the part of the control element on or in which the aforementioned radio device is also arranged. This can be the lower part, but it does not have to be.For cost reasons and to reduce the complexity of the evaluation, no more than one or two magnetic field sensors are provided, but several magnets are used, specifically on the other, relatively rotatable part. The number of magnets then determines the resolution for detecting the rotation and / or rotational position. In an alternative embodiment of the invention, the sensor means operate optically and have at least one light transmitter and at least one light receiver, wherein so-called optical detection means are arranged on or in a light path between the light transmitter and the light receiver. These can be, for example, reflective strips or narrow areas that rotate past the light transmitter and light receiver, which are arranged close to or next to each other.The reflective strips or areas have non-reflective strips or areas interspersed between them, and by moving past the light source and receiver, light is either reflected to the receiver or not. This is also a fundamental principle of the prior art.

[0012] In a further development of the invention, an underside of the lower part can be designed to rest on the user interface and can comprise or occupy between 70% and 100% of the total area of ​​the projection of the control element onto the user interface. Advantageously, this is slightly less than 100%, preferably 80% to 95%, so that the upper part can project beyond the lower part all around, meaning that essentially only the upper part is visible and accessible to the operator. This allows for a more visually appealing design. For example, the upper part can project beyond the lower part by 2% to 20% of the radius of the lower part as a kind of overhanging or overlapping edge. In this case, the contact area of ​​the underside on the user interface is still sufficiently large.

[0013] In a further development of the invention, the underside of the lower part can be designed to be non-slip or slip-resistant, so that the control element can be easily removed from the operating surface, usually upwards, since it is not attached to it. At the same time, this ensures that the lower part does not rotate when the upper part of the control element is twisted. Furthermore, the control element should ideally not shift, as this would also negatively affect ease of use and operating accuracy. Such a non-slip or slip-resistant design can be achieved with a layer that exhibits high static friction and / or high sliding friction on the operating surface.A rubber or silicone layer is generally suitable for this purpose, especially since the operating surfaces of such devices often have smooth surfaces, such as smooth plastic or glass discs. A silicone layer is particularly easy to clean and is also highly temperature-resistant. Additionally, the underside of the base can be designed with a suction cup or similar shape. This allows the control element to be pressed onto the operating surface with some pressure, generating a holding force in addition to the aforementioned non-slip or anti-slip properties of the underside surface.

[0014] In an advantageous embodiment of the invention, the touchscreen is designed without magnets or magnetic holders for the control element, i.e., neither for its mounting nor for detecting its rotation and / or rotational position. In particular, such magnets or magnetic holders are not intended to be provided on the underside of the touchscreen, or indeed anywhere on it. This simplifies the design of the control mechanism. A rotational bearing between the upper and lower parts of the control element is achieved by other means; no magnetic centering, as for example in EP 797227 A2, is necessary. Therefore, all magnets can be dispensed with.

[0015] The touchscreen can be designed with a relatively high resolution to display more information than conventional seven-segment displays. For example, the resolution can be at least 50x50 pixels, preferably at least 100x200 pixels. This allows, for instance, when using the control unit in a cooktop, the precise position of activated cooking zones and the detected position of pots placed on them to be displayed with relatively high accuracy regarding the correspondence between the relative position of the pot on the top and its display on the control unit or touchscreen.

[0016] The control element of the aforementioned radio device can incorporate an energy storage device. This can be either a rechargeable battery or a standard battery, which, while not rechargeable, can be easily replaced when depleted. The aforementioned efforts to reduce the radio device's energy consumption also enable a relatively long operating time with a standard battery. A wireless or inductive charging device can also be provided on or within the control element for charging the rechargeable battery. This eliminates the need for dirt-prone plug connectors or other electrical contacts on the battery.

[0017] In a possible further embodiment of the invention, the control element can have a light-guiding area that extends from the underside of the lower part to a lateral side or top surface of the upper part. This light-guiding area can advantageously be formed at least partially by optical fiber, i.e., as a continuous light guide at least in sections. This allows for the formation of sections that are not perfectly straight. Because the light guide extends from the underside of the lower part to the lateral side or top surface of the upper part, which is rotatable relative to the lower part, at least one transition with an air gap must be provided. This air gap can be a short one of 0.5 mm to 5 mm between the light-guiding areas. This allows light to be transmitted from the touchscreen or from special, high-intensity light sources such as LEDs.Power LEDs can be integrated into the control element to display light patterns both through and on the control element itself. These patterns can indicate specific information regarding a functional status, as an alternative to a rotary position.

[0018] The path that the light travels from an input area into the control element to an output area from the control element can be largely formed by light-guiding material, in particular more than 80% or even more than 90% of its length. This enables good light output with the brightest possible indicator light on the control element.

[0019] In a further embodiment of the invention, the lower part of the control element can be provided with a capacitively active or electrically conductive surface. This surface should be located near the underside, but advantageously not directly on the underside, so that the aforementioned non-slip or slip-resistant property can be achieved. This capacitively active or electrically conductive surface can serve to enable the control device to detect precisely where the control element has been placed on the touchscreen or user interface. The entire display, or at least a portion of it, can then be adapted to this placed control element and its position, in particular, a relatively precise fit can be generated, at least partially, around the control element. Likewise, coupling light into the control element, as described above, is then readily possible.

[0020] In a further embodiment of the invention, the upper part can have at least one electrically conductive area that has an electrically conductive connection downwards to an electrically conductive area near the underside of the lower part. This electrically conductive area near the underside can correspond to the aforementioned capacitively active or electrically conductive surface near the underside. If an electrically conductive connection to the upper part, in particular to its upper surface, is present, then placing a finger on the upper electrically conductive area can be recognized as capacitive operation on the touchscreen itself. This allows additional functions on the operating device to be triggered by means of the control element, going beyond simple rotation or twisting.

[0021] An electrical appliance according to the invention has the control device on a substantially horizontal surface or side, particularly on a top surface. This minimizes the risk of the control element slipping due to gravity. The control device can be separately integrated into this top surface of the electrical appliance, or alternatively, it can be arranged on a surface portion that essentially forms the top surface of the electrical appliance. Advantageously, the control device is arranged directly on the underside of this surface portion. An advantageous embodiment of the invention is a cooktop comprising a conventional cooktop plate with several heating elements underneath. The control device can be arranged on the cooktop plate and either inserted into a corresponding cutout.Alternatively, it can be positioned beneath the cooktop, so that the upper surface of the cooktop in this area serves as the control panel. In this case, however, the cooktop should not be made of dark, reddish-brown glass-ceramic, as is often the case, since it is difficult to achieve a clearly visible display through it. Instead, a cooktop made of transparent tempered glass can be advantageous. Other electrical appliances that can also have controls on their upper surface include ovens, washing machines, and tumble dryers. Such a surface can also be made of plastic.

[0022] On the one hand, it is considered advantageous if the control unit is designed for use with only a single control element. For example, on a cooktop, a cooking zone or heating element can then be selected by first touching a position on the display or control surface corresponding to its position on the cooking surface. The touchscreen can easily recognize this and interpret it as a selection of that cooking zone, a so-called "Select" action. Then, by rotating the control element, the power level of the heating element can be adjusted, for example. The same procedure can be followed for the next or a different cooking zone. Alternatively, the control element can be positioned on the control surface at the point where the cooking zone is located on the cooking surface.This precise positioning is interpreted as a corresponding selection; subsequently, the cooking zone's power can be adjusted by rotating the control. In a further possible embodiment of the invention, the control element can always be positioned in the center or a central area of ​​the control unit. This makes operation easier for the user.

[0023] Another alternative can be achieved using the aforementioned electrically conductive surfaces on the upper part of the control element. Touching such a conductive surface, which points towards a selected cooking zone, with a finger transmits this information capacitively to the touchscreen as the corresponding "Select" for that cooking zone. Subsequently, by turning the control element, the power level of this selected cooking zone can be adjusted, for example.

[0024] In a further development of the invention, it is possible to mount more than one control element on the user interface, for example, two or even three control elements. This allows for faster operation, for example, for adjusting the power output of multiple cooking zones, particularly by spatially assigning one control element to a specific cooking zone, which then remains unchanged when the control element is removed and repositioned. This, however, necessitates the additional effort of providing multiple control elements.

[0025] These and other features are evident not only from the claims but also from the description and the drawings, whereby the individual features, either alone or in combination, may be implemented in one embodiment of the invention and in other fields, and may represent advantageous and individually protectable embodiments for which protection is claimed here. The division of the application into subheadings and individual sections does not limit the general validity of the statements made therein. Brief description of the drawings

[0026] Exemplary embodiments of the invention are shown schematically in the drawings and are explained in more detail below. The drawings show: Fig. 1 a top view of a cooktop according to the invention as an electrical appliance with an operating device according to the invention having a rotatable control element thereon, Fig. 2 the operating device Fig. 1 Enlarged view showing user interface and rotating control element mounted on it, Fig. 3 a sectional view through the operating device Fig. 2 with a schematic representation of the internal structure of a lower part of the rotatable control element and the structure of the area of ​​the control device below the control element, and Fig. 4 an enlarged sectional view of an alternative or extended design of the rotatable control element with light guide and capacitive transmission. Detailed description of the exemplary implementations

[0027] In the Fig. Figure 1 shows a top view of a cooktop 11 according to the invention, which is an electrical appliance according to the invention. The cooktop 11 has a cooktop surface 12, advantageously made of conventional glass-ceramic, which has a top surface 13. The cooktop 11 has a cooking area 15 with four heating elements 16a to 16d. These can be of any type, for example, induction heating coils. A pot T is placed on the heating element 16a at the front left for heating or for cooking food contained therein.

[0028] In the front central area, the cooktop 11 has a control area 18, which is advantageously formed by a cutout in the otherwise rectangular cooktop surface 12. A control device 20 is inserted into this cutout. This avoids the problems mentioned earlier regarding the placement of a control device under a cooktop surface, for example, made of glass-ceramic. The control device 20, with its operating surface 21 on its upper side, should be installed as flush as possible with the surface of the cooktop surface 12 or its upper surface 13. Adherence by bonding is advantageous and is also watertight.

[0029] The user interface 21 of the operating device 20 is formed by a glass plate 22, as shown in the sectional view of the Fig. Figure 3 shows that this glass plate 22 is advantageously transparent and has sufficient hardness. Its thickness can be a few millimeters, for example, 1 mm to 3 mm. The upper surface of this glass plate 22 forms the aforementioned user interface 21. A sensor element layer 24 is provided on the underside of the glass plate 22, comprising the aforementioned capacitive sensor elements, which are distributed or provided over the entire surface. A flat TFT display 26 is provided below the sensor element layer 24, advantageously also covering the entire or substantial surface of the user interface 20. Thus, the aforementioned touchscreen is formed on the user interface 20. The placement of a finger F on the user interface 21 of the user interface 20 is capacitively detected via a sensor element of the sensor element layer 24. This triggers a specific operation. The TFT display 26, orThe touchscreen can display an indicator light 27, for example, to show a power level for the heating unit 16a at the front left with the pot T on it, here a power level "8". Of course, as shown in the enlarged top view of the... Fig. As illustrated above this indicator light 27, further information such as full text, graphic symbols, etc., is also displayed. These are precisely the well-known advantages of such a touchscreen or TFT display, also called a full display.

[0030] The operating device 20 has a control unit 29. This control unit 29 can either be intended only for the operating device 20, or advantageously it can be the control unit for the entire cooktop 11.

[0031] A control element 30, described above, is mounted on the operating direction 20 or its operating surface 21. This element is round and rotatable or twistable. As explained previously, it can also be mounted at any other location on the operating surface 21. This will be explained in more detail below.

[0032] From the sectional view of the Fig. Figure 3 shows that the control element 30 has a lower part 31 with an underside 32. Thus, the control element 30 is placed on the user interface 21 by means of this underside 32. To prevent accidental slippage or displacement, especially when the control element 30 is rotated, this underside 32 is advantageously formed of a silicone layer or similar material. This material adheres to the user interface 21, thus preventing accidental lateral slippage or displacement. At the same time, the control element 30 can still be easily removed. A microcontroller 34 is also arranged in the lower part 31. This microcontroller is connected on one side to a battery 35 or other power source and on the other side to a radio device 37. This radio device 37 can operate according to one of the aforementioned radio standards, advantageously using BLE or ZigBee.Furthermore, the microcontroller 34 is connected to a reflective light sensor 39a, which is arranged on a slightly narrower, tall central section of the lower part 31. Its direction of action is directed outwards. Its signals are evaluated by the microcontroller 34 and transmitted via the radio device 37 to the counterpart radio device 23 and thus to the control unit 29 for use as an operator.

[0033] A ring-shaped ball bearing 38 is provided on the flat, outwardly projecting shoulder of the lower part 31, for example, by injection molding, snapping, or gluing. An upper part 41 is mounted on this ball bearing 38, advantageously also fastened, for example, by clamping, snapping, or gluing. This rotary bearing allows the upper part 41 to rotate very freely and almost frictionlessly relative to the lower part 31 about a rotation axis D (shown with a dashed line). The ball bearing 38 can absorb axial and radial forces, at least up to a certain extent under normal operating conditions.

[0034] The one in Fig. The upper part 41, also shown in enlarged form, has a top surface 42, advantageously essentially flat, and an outer lateral side 43. This lateral side overlaps the ball bearing 38 and the lower part of the lower part 31 with a thin section, extending almost to the operating surface 21. Only a narrow air gap is provided here, so that the lateral side 43 does not rub against the operating surface 21. This prevents dirt from entering the interior of the operating element 30. Furthermore, only the upper part 41 is visible from the outside, and not the lower part 31.

[0035] The upper part 41 has reflective strips 39b on an inwardly facing inner surface that runs essentially parallel to the lateral surface 43, preferably circumferentially and in a specific pattern. These reflective strips 39b move past the reflective light sensor 39a when the control element 30 is rotated, thus enabling the detection of a rotation and / or rotational position between the upper part 41 and the lower part 31 in a known manner. This can be used as a corresponding control for the cooktop 11, in this case for the heating element 16a, according to Fig. 1. evaluated and used. No further explanation is needed regarding this aspect, which is already known from the prior art.

[0036] Instead of the depicted detection of a rotation between lower part 31 and upper part 41 by means of a reflective light sensor 39a and the reflective strips 39b, other methods can also be used, for example by means of magnets instead of the reflective strips 39b and at least one Hall sensor instead of the reflective light sensor 39a.

[0037] The upper surface 42 and the lateral side 43 of the upper part 41 can be made of a robust and visually appealing material, for example, metal such as aluminum or stainless steel, or alternatively, plastic. The placement of the control element 30 on a specific location of the control device 20 or the operating surface 21 can be detected by the presence of a metallic surface or part on the lower part 31, advantageously above a silicone underside 32. These surfaces or parts can, in turn, be detected by the capacitive sensor elements of the control device 20, particularly by the sensor element position 24. If this metallic surface is significantly larger than the contact area of ​​the finger F on the operating surface 21, the control element 30 can, so to speak, have a signature for recognition by the control device 20. This signature is characteristic and distinguishes it, above all, from any other operation by a finger or the like.Then the control unit 20 knows not only that the control element 30 has been placed somewhere on it, but advantageously also its exact placement location. On the one hand, it may be intended that the control element 30 is always placed in the same position, for example, centrally and slightly offset forward on the control surface 21. Thus, its relative position within the control surface 21 corresponds to the relative position of the control unit 20 on the cooktop 12. On the other hand, if the control element 30 is placed in a different position, advantageously with a deviation of at least 5 mm or at least 15 mm, this is detected, and simultaneously no signals or operating commands from the control element 30 are used or implemented.

[0038] Alternatively, the control element 30 can be used for operation at essentially any location on the control device 20 or on its user interface 21. This provides greater flexibility. In an embodiment of the invention, it can also be provided that this relative position of the control element 30 within the user interface 21 is recognized and interpreted as the selection of one of the heating devices 16a to 16d. For example, to adjust the power of the heating device 16c, the control element 30 could be placed at the rear right of the user interface 21, i.e., at the corresponding relative position. This means that the heating device 16c is considered selected for a subsequent power adjustment, which can then be made by directly turning the control element 30 or its upper part 41.The control element 30 can then be moved to corresponding relative positions on the user interface 21 for selection and power setting of the corresponding heating device 16.

[0039] In the Fig. Figure 4 on the left shows how the control element 30 can be further developed. The left section illustrates how an LED 28, preferably a relatively bright LED, is arranged below the TFT display 26, which is translucent in this area. Alternatively, the LED 28 could also be arranged in a cutout within or above the display. The LED 28 should emit directional light vertically upwards. Above this, a vertically extending lower light guide 40 is provided in the lower part 31. Connected to this, so to speak, an upper light guide 44 is provided in the upper part 41, ending flush with the top surface 42 of the upper part 41. Thus, the light from the LED 28 at the very bottom can create a luminous effect at the very top surface 42 of the control element 30.Depending on the arrangement of the lower light guide 40 and / or the upper light guide 44, and especially considering any relative rotation of the two, this can occur in different positions. Instead of the LED 28, a particularly bright area of ​​the TFT display 26 may also cause a luminous phenomenon at the top of the control element 30 by means of the light guides 40 and 44.

[0040] An alternative further development of a control element 30 is shown on the right in the Fig.Figure 4 shows a configuration that is fundamentally independent of the design on the left side described above. Here, a metal surface 45a is provided or flush-mounted on the upper surface 42 of the upper part 41. The metal surface 45a is electrically connected to a lower metal surface 45a' located on the underside of the upper part 41. Directly opposite it, on the upper surface of the lower part 31, another metal surface 45b is provided. This is similarly electrically connected to a lower metal surface 45b'. Thus, placing a finger F on the upper metal surface 45a can be interpreted as an actuation at the same location above the touchscreen or sensor element position 24 using the surface of the metal surface 45b'.Thus, the control device 20 can be operated not only directly on the operating surface 21 with a finger or by rotating the control element 30, but also by a corresponding finger touch at a specific point on its upper part 41. This allows, for example, a start signal or the like to be triggered.

[0041] As a further alternative, a dashed line is shown connecting the metal surface 45a' to a metal surface 45a'' located on the lateral side 43 of the upper part 41. This is intended to illustrate that such an area for actuation by means of a finger can be provided not only on the upper surface 42, but also on the lateral side 43.

[0042] The control unit 29 of the operating device 20 can store information about the surface area of ​​the control element 30, or the area it covers. This allows it to detect whether an electrical connection of a finger to the lower metal surface 45b' of the touchscreen occurs within the area covered by the control element 30. Depending on this, a different operating action can be triggered. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102006039235 A1

[0002] DE 102012213693 A1 [0003, 0010] EP 797227 A2

[0014]

Claims

[1] Operating device for an electrical appliance, wherein the operating device has a control and a flat, capacitive touch screen for operation by placing or moving a finger on the touch screen, wherein the touch screen has a display, a user interface and capacitive sensor elements below the user interface, characterized by , that: - the operating device has at least one operating element which is arranged on the operating surface in a movable and removable manner, - the control element is designed in two parts with a lower part and an upper part, - the lower part and the upper part can be rotated relative to each other about an axis of rotation which is vertical to the operating surface with the operating element on it, - the operating element has sensor means for detecting a twist and / or rotational position between the lower part and the upper part, - the control element has a radio device for wireless transmission of signals to a counterpart radio device of the control device, - the radio device is designed to transmit information for detecting the rotation and / or rotational position to the control of the operating device by means of the counter radio device, - the capacitive sensor elements are distributed over the surface of the touch screen, in particular they are evenly distributed, - the control of the operating device is designed to detect the position of the operating element on the user interface by means of the capacitive sensors and, if necessary, to adapt or change a display around the operating element accordingly. [2] Operating device according to claim 1, characterized bythat the operating element has a pivot bearing for mounting the upper part on the lower part of the operating element, wherein the pivot bearing is preferably ring-shaped and absorbs vertical and horizontal bearing forces, wherein in particular the pivot bearing is circular in shape with a diameter between 40% and 90% of the diameter of the operating element. [3] Operating device according to claim 1 or 2, characterized by that the sensor means for detecting a twist and / or rotational position between the upper part and the lower part: - either are designed to operate magnetically with at least one magnet and at least one magnetic field sensor, - or are optically operated with at least one light transmitter, at least one light receiver and optical detection means in the light path between the two. [4] Operating device according to one of the preceding claims, characterized bythat the lower part has an underside for resting on the operating surface, wherein the underside has an area between 70% and 100% of the total area of the projection of the operating element onto the operating surface, wherein preferably the upper part projects beyond the lower part all around by 2% to 20% of the radius of the lower part. [5] Operating device according to one of the preceding claims, characterized by that an underside of the lower part is designed to be non-slip or anti-slip, in particular with a layer with high static friction and / or sliding friction on the operating surface, preferably with a rubber layer or with a silicone layer. [6] Operating device according to one of the preceding claims, characterized by that the touch screen is designed without magnets or magnetic holders, in particular not on its underside, preferably without any magnets. [7] Operating device according to one of the preceding claims, characterized by that the touch screen has a resolution of at least 50 x 50 pixels, preferably at least 100 x 200 pixels. [8] Operating device according to one of the preceding claims, characterized by that the control element has an energy storage device, in particular an accumulator or a replaceable battery. [9] Operating device according to one of the preceding claims, characterized by that the operating element has a light-guiding region from a bottom side of the lower part to a top side of the upper part, wherein the light-guiding region is preferably formed at least partially by light-guiding material, in particular to more than 80% or to more than 90% of the length from the bottom side to the top side. [10] Operating device according to one of the preceding claims, characterized by that the lower part has a capacitively effective or electrically conductive surface, in particular near the underside. [11] Operating device according to one of the preceding claims, characterized by that the upper part has at least one electrically conductive region which has an electrically conductive connection downwards to an electrically conductive region near a bottom of the lower part such that the placing of a finger on the electrically conductive region on the upper part or on the top side is recognizable as capacitive operation on the touch screen. [12] Electrical appliance with an operating device according to one of the preceding claims, wherein the electrical appliance has the operating device on a substantially horizontally extending upper side, wherein preferably the operating device is inserted separately into the upper side of the electrical appliance or is arranged on a surface part essentially forming the upper side of the electrical appliance, in particular is arranged below [13] Electrical device according to claim 12, characterized bythat it is a hob with a hob plate and several heating devices under the hob plate, wherein preferably the operating device is arranged on the hob plate and the touch screen is arranged under the hob plate with the upper side of the hob plate in this area as the operating surface of the operating device. [14] Electrical appliance according to claim 12 or 13, characterized by at least two removable and identical control elements on the control device.

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