Operator control unit for a motor vehicle having a transilluminable carrier body that is visible to an operator

Abstract

The invention relates to an operator control unit (1) for a motor vehicle, having: a transilluminable carrier body (10); a switching assembly (20) which is arranged on a visible surface (13) of the carrier body (10) facing an operator; and an optical transmitter (31) and an optical sensor (32) which are arranged on a rear side (R) of the carrier body (10) facing away from the operator; wherein: the switching arrangement (20) has at least one switching element (21, 22) which is movable between an actuated position, in which the switching element (21, 22) lies against a contact region (11, 12), assigned to the switching element (21, 22) in question, of the surface (13), and a non-actuated position, in which the switching element (21, 22) in question is spaced from the surface (13); and the optical transmitter (31) is designed to emit light through the carrier body (10) to the contact region (11, 12), and the optical sensor (32) is designed to detect light coupled out of the carrier body (10) and from this to determine the position of the at least one switching element (21, 22) and generate a switching signal corresponding to the position.

Description

[0001] Marquardt GmbH

[0002] Q081PCT

[0003] Control unit for a motor vehicle with a translucent carrier body visible to an operator

[0004] Description:

[0005] The invention relates to a control unit for a motor vehicle with a carrier body that is translucent and visible to an operator.

[0006] Various control units for motor vehicles are known from the state of the art, which serve to trigger or control a function of the vehicle.

[0007] Based on various requirement profiles for such operating units, these must be adapted to their respective applications or be compatible for different uses. With regard to safety, for example, it may be necessary that there be a hermetic and / or galvanic isolation between an operating element that can be actuated by the operator and the switching state detection, so that the operator cannot come into contact with live components or that the switching state detection and other components cannot be damaged by penetrating liquids or particles.

[0008] Furthermore, modern motor vehicles often offer a wide variety of equipment options, for which as many identical parts as possible should be used to reduce costs. Accordingly, it is desirable that control units and their operating elements can be easily installed or retrofitted without requiring the use of different mounting bodies.

[0009] In addition, increasingly transparent components are being used for a high-quality look in motor vehicles, but no electronic components should be visible in or under them.

[0010] An operating unit that fulfills at least some of these requirements is known, for example, from German patent application DE 202024 105266 U1. This patent proposes a capacitive operating unit in which a switching arrangement is positioned on the visible side of a carrier body and a capacitive sensor element for detecting the switching states is located on the reverse side of the carrier body. Since only capacitive coupling and thus galvanic isolation exist through the carrier body, a high level of safety is ensured, and a vehicle can be implemented in various versions without the switching arrangement while retaining a large number of identical parts.

[0011] However, operating units such as those known from DE 202024 105266 U1 have the disadvantage that they are subject to limitations with regard to the transparency or translucency of the carrier body, and that the sensor element must be located directly opposite and in close proximity to the switching arrangement in order to ensure the necessary capacitive coupling.

[0012] The invention is therefore based on the objective of overcoming the aforementioned disadvantages, meeting the given requirements and providing an alternative for control units for motor vehicles.

[0013] This problem is solved by the combination of features according to claim 1.

[0014] According to the invention, a control unit for a motor vehicle is proposed. This unit comprises a translucent, at least transparent, and preferably transparent carrier body, a switching arrangement, an optical transmitter, and an optical sensor. The switching arrangement is located on a user-facing surface of the carrier body, preferably directly or via an adhesive layer mentioned below. The user-facing surface of the carrier body is thus facing the operator and visible to them. The optical transmitter and the optical receiver are located on a rear side of the carrier body facing away from the operator, and these components can be integrated as a single electronic module and, for example, mounted on a common circuit board.Alternatively, the optical transmitter and the optical receiver can also be arranged separately on the rear side of the carrier body, facing away from the operator. The switching arrangement already mentioned has at least one switching element, which preferably has a refractive index different from that of the carrier body, and is formed of an elastomer, particularly in the area in contact with the surface of the carrier body. The switching element can be moved by the operator between an actuated position, in which the switching element rests against a contact area of ​​the visible surface assigned to the respective switching element, and an unactuated position, in which the respective switching element is spaced away from the visible surface, so that optical reflection properties or...Absorption properties at the respective contact area of ​​the visible surface of the carrier body can also be changed depending on the position of the respective switching element. Furthermore, the optical transmitter is configured to emit light through the carrier body to the contact area. In addition, the optical sensor is configured to detect light coupled out from the carrier body, for example, reflected at the contact area, and to determine the position of at least one switching element from the coupled or reflected light. It then generates a switching signal corresponding to the position, either directly, for example, by an integrated evaluation unit, or indirectly, for example, by an external evaluation unit. This external evaluation unit, together with the optical sensor and / or the optical transmitter, can form an electronic module and may be mounted on a common circuit board.

[0015] For clarification, in a variant where the switching arrangement has at least two switching elements, each of these can be moved by the operator between an actuated position, in which the respective switching element rests against a contact area of ​​the visible surface, and an unactuated position, in which the respective switching element is spaced away from the visible surface. Accordingly, the optical transmitter is configured to emit light through the carrier body to the contact areas or to one of the contact areas, with one optical transmitter being provided for each switching element and assigned to the respective contact area in the latter variant. The optical sensor is preferably configured to detect the light coupled out of the carrier body, for example, reflected at the contact areas, and to extract a value from the coupled or...The reflected light is used to determine the positions of at least two switching elements and to generate a switching signal corresponding to each position. Alternatively, several optical sensors can be provided, with each optical sensor being assigned to exactly one switching element to determine its position.

[0016] The optical sensor(s) can also simply provide sensor values, which can then be evaluated in the aforementioned separate evaluation unit, enabling the evaluation unit to generate the respective switching signals. Accordingly, such an evaluation unit can be understood as either integrated into the at least one optical sensor or as separate from it but connected via signal technology.

[0017] As already mentioned, the carrier body is preferably transparent.

[0018] Additionally or alternatively, another advantageous further training method provides that the carrier body is made of glass.

[0019] The optical transmitter is, in particular, a light source, especially an LED. Alternatively or additionally, the optical transmitter can be configured to emit light with a wavelength preferably exclusively greater than 780 nm, or more generally, light in the infrared range, or exclusively light in the infrared range. An IR LED is therefore particularly preferred as the optical transmitter. However, any light source configured to emit any light in the range invisible to the human eye, and preferably exclusively this light, can be used as an alternative.

[0020] To optimize the coupling of light into the carrier body and, if necessary, also the coupling of light out of the carrier body, the carrier body preferably has a coupling surface on its rear side, on which the optical transmitter and, if necessary, the optical sensor are arranged.

[0021] A particularly advantageous further development, according to a first variant, provides that the coupling surface is arranged at an angle relative to the surface, or that the coupling surface and the surface have a predetermined angle to each other, and that the optical transmitter is arranged on the carrier body such that the light coupled into the carrier body by the optical transmitter is reflected away from the optical sensor at the contact area of ​​the switching element in the unactuated position, and reflected towards the optical sensor at the contact area of ​​the switching element in the actuated position. If the light is reflected away from the optical sensor by the switching element in the unactuated position, the light is not detected by the sensor, so that the optical sensor generates a switching signal indicating that the respective switching element is in the unactuated position.If the light is reflected by the switching element in the actuated position to the optical sensor, the light is detected by the latter, so that the optical sensor generates a switching signal according to which the respective switching element is in the actuated position.

[0022] A second, equally advantageous variant, based on a reversal of principle, involves tilting the coupling surface relative to the surface and arranging the optical transmitter on the carrier body such that the light coupled into the carrier body by the optical transmitter is reflected at the contact area of ​​the switching element with the switching element in the unactuated position to the optical sensor, and at the contact area of ​​the switching element with the switching element in the actuated position, it is reflected from the optical sensor path. When the light is reflected from the switching element in the unactuated position to the optical sensor, it is detected by the sensor, which then generates a switching signal indicating that the respective switching element is in the unactuated position.Similarly, the light is reflected away from the optical sensor by the switching element in the actuated position, so that the light is not detected by it and the optical sensor generates a switching signal according to which the respective switching element is in the actuated position.

[0023] In both variants, the optical sensor is designed to detect the light reflected at the contact area to the optical sensor and to determine the position of at least one switching element from the reflected light.

[0024] A third variant, which is not based on direct reflection, provides that the coupling surface is tilted relative to the surface and the optical transmitter is arranged on the carrier body in such a way that the light coupled into the carrier body by the optical transmitter is essentially or predominantly reflected back into the carrier body at the contact area of ​​the switching element in the unactuated position, generating a predetermined first light intensity in the carrier body. Conversely, at the contact area of ​​the switching element in the actuated position, the light is essentially or predominantly coupled out of the carrier body into the switching element, generating a predetermined second light intensity in the carrier body. Based on this, the optical sensor is designed to detect the light.to detect the light intensity generated by the light coupled into the carrier body and to determine the position of at least one switching element from the light intensity.

[0025] If several switching elements are present, it is advantageous in the third variant mentioned if each switching element is assigned an optical transmitter and preferably also an optical receiver.

[0026] Regardless of how the switching state or position of the switching element is determined, it is advantageous if the coupling surface is tilted relative to the surface of the carrier body and the optical transmitter is arranged on the coupling surface in such a way that the light coupled into the carrier body by the optical transmitter is essentially completely reflected back into the carrier body at the contact area of ​​the switching element in the unactuated position, thus creating the conditions for total internal reflection (TIR).

[0027] A further development is particularly advantageous in which the switching arrangement has at least two switching elements with a respective contact area and the operating unit has exactly one optical sensor, which is designed to detect a light coupled out from the carrier body in a manner specifically assignable to each contact area and to determine the position of the respective switching element from the coupled out light in a manner specific to each contact area and to generate a switching signal corresponding to the position of the respective switching element.

[0028] However, an operating unit can also have several switching arrangements, which are spaced apart from one another on the surface of the carrier body. Each switching arrangement can be assigned at least one optical transmitter and at least one, but preferably exactly one, optical receiver. Alternatively, for example, each switching arrangement can be assigned at least one optical transmitter and several switching arrangements can be assigned one or exactly one optical receiver.

[0029] In principle, the optical sensor can be a simple brightness sensor, with each switching element preferably assigned such an optical sensor. However, optical sensors that allow matrix evaluation are preferably used, thus determining both the light intensity and the distribution of the light intensity across their sensor area, so that the position of several switching elements can be determined with such an optical sensor.

[0030] Instead of an optical sensor, which only determines the light intensity and measurements comparable to grayscale or a black and white evaluation, a simple camera could also be used as the optical sensor.

[0031] To minimize unwanted scattering of light reflected from the switching arrangement or the contact surfaces, the carrier body can further comprise at least one capture surface designed to extract and / or absorb light coupled into the carrier body from the optical transmitter and reflected within it, thereby reducing scattered light. For this purpose, the capture surface can, for example, be positioned in the beam path of the light reflected from the switching arrangement or the contact surfaces but not reflected to the optical sensor. The capture surface can, on the one hand, have an angle optimized for extraction depending on the beam path and / or be frosted.

[0032] In addition to or as an alternative to such a capture surface, an attachment component arranged directly on the carrier body can be provided, which is preferably designed to absorb light in general and IR light in particular. To enable the optical sensor to determine reference values ​​or measured values ​​serving as a baseline, it can also be provided that the optical transmitter is designed to emit the light through the carrier body to the contact area in a predefined pulsed manner, i.e., with predetermined pauses between each two light pulses, and that the optical sensor is designed to determine a reference value by means of the pulsing.

[0033] Furthermore, the switching arrangement can have at least one base body fixed to the surface, preferably by adhesive bonding, which is integrally designed as an operating element acting on the at least one switching element or is connected to an operating element acting on the at least one switching element. The operating element can, for example, be a rocker switch assigned to each pair of switching elements, which can actuate the switching elements individually by tilting it or together by pressing it, thus enabling four positions of the operating element, which lead to distinguishable combinations of the positions of the two switching elements. Alternatively, however, a separate button can be provided for each switching element, which is held on the base body.

[0034] Building on this, it can be provided that at least one contact layer of the base body in contact with the surface and / or an adhesive layer arranged between the base body and the surface are colored differently from the switching element, resulting in different optical reflection and / or absorption properties. For example, the base body and / or the adhesive layer can be black and the switching element(s) white, resulting in advantageous contrast. Accordingly, the different reflection and absorption properties of the two colors or components lead to an increase in sensor contrast, thus enabling better differentiation between the two system components.

[0035] To indicate to the operator that an action has been performed, i.e., that the actuated position has been reached, the operating unit may also include at least one haptic element for generating haptic feedback, wherein at least one switching element is associated with or integrally formed with a haptic element. The haptic element is designed to generate haptic feedback for the operator when the switching element moves from its unactuated position to its actuated position. Examples of suitable haptic elements include a silicone dome, a switching mat, or a snap disc.

[0036] The features disclosed above can be combined in any way, provided that this is technically possible and that they do not contradict each other.

[0037] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show:

[0038] Fig. 1 shows a control unit in an unactivated position;

[0039] Fig. 2 shows the control unit in the unactivated position with beam path;

[0040] Fig. 3 shows the control unit in a first actuated position;

[0041] Fig. 4 shows the control unit in a second actuated position;

[0042] Fig. 5 shows the control unit in a third actuated position;

[0043] Fig. 6 shows a variant of the control unit. The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features.

[0044] Figures 1 to 5 show an identical control unit 1 with different positions of the control element 24 or the switching elements 21, 22, on which the control element 24 acts. Figure 6 shows a variant of the control unit 1 depicted in Figures 1 to 5, whereby what is stated with regard to Figures 1 to 5 also applies directly to the control unit 1 according to Figure 6.

[0045] Basically, an operating unit 1 is to be provided, which operates with a completely closed surface on a body that is transparent for design reasons.

[0046] Figure 1 shows such an operating unit 1 according to one possible embodiment. This unit has a translucent carrier body 10, which in this case is made of glass, a switching arrangement 20 and an electronic module 30, whereby the carrier body 10 can also be made of another transparent material.

[0047] The operating unit 1 has a visible side S facing the operator and a rear side R facing away from the operator. On the visible side S, the carrier body 10 is defined by a corresponding visible surface 13 on which the switching arrangement 20 is arranged.

[0048] Regardless of the specific design of the switching arrangement 20, it is essential that it has at least one, and in this case exactly two, switching elements 21, 22, which can be brought into contact with the surface 13 in a respective contact area 11, 12, corresponding to their respective actuated position. A switching element 21, 22 spaced from the surface 13 is accordingly in its unactuated position. The electronic module 30 is provided on the rear side of the carrier body 10, which has an optical transmitter 31 and an optical sensor 32, which are arranged on a common circuit board 33.

[0049] The optical transmitter 31 is designed to couple infrared light (IR light) into the carrier body 10 and in the direction of the switching arrangement 20, whereby the IR light is reflected at the switching arrangement 20 depending on the positions of the switching elements 21, 22. Depending on the reflection of the IR light, the optical sensor 32 acquires various measurement data from which it determines the position of the switching elements 21, 22 and generates a corresponding switching signal based on this.

[0050] To optimize the coupling of IR light from the optical transmitter 31 into the carrier body 10, and also to optimize the coupling of IR light from the carrier body 10 into the optical sensor 32, a coupling surface 14 is provided for this purpose. The coupling surface 14 and the surface 13 are tilted relative to each other such that the conditions for total internal reflection are met for the IR light coupled in from the optical transmitter 31 with the switching elements 21, 22 in their unactuated position, so that the light is essentially completely reflected in the contact areas 11, 12 as long as the switching elements 21, 22 are not in contact with the contact areas 11, 12, i.e., as long as they are unactuated.

[0051] The optical sensor 32 is not merely a brightness sensor, but a sensor that can determine both the light intensity and its two-dimensional distribution across its sensor surface. This allows a single sensor 32 to detect the light reflected from each of the contact areas 11, 12 or from each of the switching elements 21, 22, and from this, the positions of the switching elements 21, 22 can be determined. According to the present embodiment, the switching arrangement 20 is implemented as a rocker switch. This switch has a base body 23 fixed to the surface 13 by an adhesive layer 25. The switching elements 21, formed by silicone domes and thus providing integral haptic feedback, are arranged on this base body.Furthermore, a control element 24 is mounted on the base body 23 so that it can be tilted and moved in the direction of the surface 13, so that the control element 24 can assume four different positions and four different positions of the switching elements 21 can be realized.

[0052] Figure 2 shows an unactuated position of the control element 24, in which no external force acts on the control element 24.

[0053] Figure 3 shows a first actuated position of the control element 24, in which the control element 24 is tilted in a first direction by an external force K1 applied by the operator on the base body 23 and the second switching element 22 is moved from its unactuated position to its actuated position by the base body 23, so that the second switching element 22 rests on the surface 13 in the associated contact area 12, but the first switching element 21 is spaced away from the surface 13 and accordingly remains in its unactuated position.

[0054] Figure 4 shows a second actuated position of the control element 24, in which the control element 24 is tilted by an external force K2 applied by the operator on the base body 23 in a second direction opposite to the first direction and the first switching element 21 is moved by the base body 23 from its unactuated position to its actuated position, so that the first switching element 21 rests on the surface 13 in the associated contact area 11, but the second switching element 22 is spaced away from the surface 13 and accordingly remains in its unactuated position.Figure 5 shows a third actuated position of the control element 24, in which the control element 24 is pressed against the base body 23 in the direction of the surface 13 by an external force K3 applied by the operator, and both switching elements 21, 22 are moved from their unactuated positions to their actuated positions by the base body 23, so that both switching elements 21, 22 are in contact with the surface 13 in the associated contact areas 11, 12.

[0055] As an example, a sensor image 34 captured by the optical sensor 31 is shown in part, in which the base body 23, more precisely its layer or adhesive layer 24 which is in contact with the surface 13, and depending on the position, no switching element 21, 22, one of the switching elements 21, 22 or both switching elements 21, 22 are detected, which are in contact with the respective contact area 11, 12 on the surface 13.

[0056] To illustrate the operating principle, figures 2 to 5 also show the relevant beam paths S1, S2 of the IR light coupled into the carrier body 10 by the optical transmitter 31 and striking the contact areas 11, 12.

[0057] As shown in Figure 2, none of the switching elements 21, 22 are actuated, so that the light along the beam paths S1, S2 is reflected back into the carrier body 10 and away from the optical sensor 32 at the contact areas 11, 12. This sensor, or any evaluation electronics connected to the optical sensor 32, therefore does not generate a switching signal.

[0058] As shown in Figure 3, only the second switching element 22 is actuated, so that the light along the associated beam path S2 is reflected at the contact area 12 back into the carrier body 10 and to the optical sensor 32. This sensor, or the evaluation electronics optionally connected to the optical sensor 32, thus generates a switching signal indicating that the second switching element 22 is actuated. The same applies to the beam path S1, or the first switching element 21, as described in Figure 2.

[0059] As shown in Figure 4, only the first switching element 21 is actuated, so that the light along the associated beam path S1 is reflected at the contact area 11 back into the carrier body 10 and to the optical sensor 32. This sensor, or the evaluation electronics optionally connected to the optical sensor 32, thus generates a switching signal indicating that the first switching element 21 is actuated. The same applies to the beam path S2, or the second switching element 22, as described in Figure 2.

[0060] As shown in Figure 5, both switching elements 21, 22 are actuated, so that the light is reflected along the associated beam paths S1, S2 at the contact area 12 back into the carrier body 10 and to the optical sensor 32. This sensor, or the evaluation electronics optionally connected to the optical sensor 32, thus generates a switching signal indicating that both switching elements 21, 22 are actuated.

[0061] Figure 6 further illustrates that the control unit 1 can include or be combined with a decorative cover 41. Such a decorative cover 41 conceals edge sections of the carrier body 10, so that both the edge sections and any electronics arranged in this area are not visible to the operator.

[0062] Furthermore, the carrier body 10 can have a capture surface 15, which can be combined with an attachment 42 for light absorption. For example, a frosted capture surface 15 and the light-absorbing attachment 42 can significantly reduce the scattered light component from the light coupled into the carrier body 10 by the optical transmitter 31, thus improving the sensor accuracy of the optical sensor 32.

Claims

Patent claims 1. Control unit (1 ) for a motor vehicle, with a translucent carrier body (10), a switching arrangement (20) which is arranged on a user-facing, view-side surface (13) of the carrier body (10), and an optical transmitter (31) and an optical sensor (32) which are arranged on a rear side (R) of the carrier body (10) facing away from the user, wherein the switching arrangement (20) has at least one switching element (21, 22) which is movable between an actuated position, in which the switching element (21, 22) rests against a contact area (11, 12) of the visible surface (13) associated with the respective switching element (21, 22), and an unactuated position, in which the respective switching element (21, 22) is spaced away from the visible surface (13), such that optical reflection properties at the respective contact area (11, 12) of the visible surface (13) of the carrier body (10) can be changed depending on the position of the respective switching element (21, 22), wherein the optical transmitter (31) is configured to emit light through the carrier body (10) to the contact area (11, 12), and the optical sensor (32) is configured to detect light coupled out of the carrier body (10). detect and from this determine the position of at least one switching element (21 ,22) to determine and to generate a switching signal corresponding to the position.

2. Control unit according to claim 1 , wherein the carrier body (10) is transparent and / or made of glass.

3. Control unit according to claim 1 or 2, wherein the optical emitter (31) is a light source and / or is designed to emit light with a wavelength of more than 780 nm.

4. Control unit according to one of the preceding claims, wherein the carrier body (10) has a coupling surface (14) on the rear side (R) on which the optical transmitter (31) is arranged.

5. Control unit according to the preceding claim, wherein the coupling surface (14) is tilted relative to the surface (13) and the optical transmitter (31) is arranged on the carrier body (10) in such a way, that the light coupled into the carrier body (10) by the optical transmitter (31) is reflected away from the optical sensor (32) at the contact area (11, 12) of the switching element (21, 22) in its unactuated position, and is reflected towards the optical sensor (32) at the contact area (11, 12) of the switching element (21, 22) in its actuated position, or that the light coupled into the carrier body (10) by the optical transmitter (31) is reflected at the contact area (11, 12) of the switching element (21, 22) towards the optical sensor (32) in its unactuated position, and is reflected away from the optical sensor (32) at the contact area (11, 12) of the switching element (21, 22) in its actuated position. wherein the optical sensor (32) is configured to detect the light reflected at the contact area (11, 12) to the optical sensor (32) and to determine the position of the at least one switching element (21, 22) from the reflected light.

6. Control unit according to claim 4, wherein the coupling surface (14) is tilted relative to the surface (14) and the optical transmitter (31) is arranged on the carrier body (10) in such a way, that the light coupled into the carrier body (10) by the optical transmitter (31) is reflected back into the carrier body (10) at the contact area (11, 12) of the switching element (21, 22) in its unactuated position and generates a predetermined first light intensity in the carrier body (10), and is coupled out of the carrier body (10) into the switching element (21, 22) at the contact area (11, 12) of the switching element (21, 22) in its actuated position and generates a predetermined second light intensity in the carrier body (10). wherein the optical sensor (32) is designed to detect the light intensity generated by the light coupled into the carrier body (10) and to determine the position of the at least one switching element (21, 22) from the light intensity.

7. Control unit according to one of claims 4 to 6, wherein the coupling surface (14) is tilted relative to the surface (13) and the optical transmitter (31) is arranged on the coupling surface (14) such that the light coupled into the carrier body (10) by the optical transmitter (31) is essentially completely reflected back into the carrier body (10) at the contact area (11, 12) of the switching element (21, 22) with the switching element (21, 22) in its unactuated position.

8. Control unit according to one of the preceding claims, wherein the switching arrangement (20) has at least two switching elements (21, 22) with each associated contact area (11, 12) and the operating unit (1) has exactly one optical sensor (32) which is configured to detect light coupled out from the carrier body (10) in a manner specifically assignable to each contact area (11, 12) and to determine the position of the respective switching element (21, 22) from the coupled out light which can be specifically assigned to each contact area (11, 12) and to generate a switching signal corresponding to the position of the respective switching element (21, 22).

9. Control unit according to one of the preceding claims, wherein the carrier body (10) has at least one capture surface (15) which is designed to couple out and / or absorb light coupled into the carrier body (10) from the optical transmitter (31) and reflected in the carrier body (10) in order to reduce scattered light from the carrier body (10).

10. Control unit according to one of the preceding claims, wherein the optical transmitter (31) is configured to emit the light in a predefined pulsed manner through the carrier body (10) to the contact area (11, 12), and the optical sensor (32) is configured to determine a reference value for the unactuated position of the at least one switching element (21, 22) by means of the pulsing.

11. Control unit according to one of the preceding claims, wherein the switching arrangement (20) has at least one base body (23) fixed on the surface, which is integrally designed as an operating element (24) acting on the at least one switching element (21, 22) or is connected to an operating element (24) acting on the at least one switching element (21, 22), wherein at least one contact layer of the base body (23) in contact with the surface (13) and / or an adhesive layer (25) arranged between the base body (23) and the surface (13) are colored differently from the switching element (21, 22), resulting in different optical reflection properties and / or different optical absorption properties.

12. Control unit according to one of the preceding claims, furthermore comprising at least one haptic element, wherein at least one switching element (21 , 22) is associated with a haptic element or is integrally formed with it, wherein the haptic element is designed to generate haptic feedback for the operator when the switching element (21 , 22) is moved from its unactuated position to its actuated position.

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