Control unit with sensor film attached by opposing tabs for capacitive touch detection, associated use and mounting method

Abstract

Control unit (1), comprising: an aperture (2) that forms a viewing surface (S) facing the viewer (B); a support (3) arranged on the side of the aperture (2) facing away from the viewer (B); a film layer structure (4) arranged between the carrier (3) and the aperture (2), bearing against at least one contact surface (A) formed on the side of the carrier (3) and / or the aperture (2), characterized in that the film layer structure (4) forms at least one pair of two oppositely arranged tabs (4a, 4a') which point with their free end (4b, 4b) in opposite directions of extension (y, y'), wherein the tab (4a, 4a') each extend through an opening (3a, 3a') surrounded by the contact surface (A) in the direction of extension (y, y') in order to fix the film layer structure (4) to the aperture (2) or the carrier (3) by pairwise interaction of the tabs (4a, 4a') at least in a direction perpendicular to the contact surface (A).

Description

[0001] The invention relates to a control element that essentially comprises three components: a diaphragm, a sensor film, and a substrate. While the diaphragm serves to provide an optically attractive viewing surface with, for example, a decoration created by a decorative coating of a decorative film as a substrate, with a symbol, with one or more haptically perceptible orientation aids, and / or with a backlit display area, the sensor film, which can be a film layer structure, has, among other things, the task of providing one or more electrodes or an electrode array for capacitive touch sensing in order to detect, for example, the approach of a finger or an input device to a sensing or touch area located within the viewing surface, or to detect such contact.The capacitive touch sensor can, for example, be configured for spatial detection, with the sensor film comprising an array of intersecting, insulated electrode tracks. The carrier serves to attach the control unit to a supporting component, such as a vehicle dashboard, center console, or similar structure. It is further designed to secure the sensor film between the aperture and the carrier and, in particular, provides surface support for the sensor film. For a touch-sensitive control unit, reliable and precise positioning of the sensor film is crucial, as the touch sensor is sensitive to deviations from the predetermined distance of the sensor film from the viewing surface in the direction perpendicular to the viewing surface.However, reliable and reproducible positioning of the sensor film in a direction parallel to the viewing surface is also crucial, as otherwise, the optical or haptic features used to mark or delimit the corresponding touch area will no longer correspond to the arrangement and locally varying sensitivity of the sensor film due to mispositioning. To circumvent this problem, the sensor film is partially bonded to the aperture or the carrier by means of a material bond, for example, by welding, particularly ultrasonic welding. This makes the assembly of the entire control unit difficult and complex, as the energy direction transmitters for ultrasonic welding, in particular, must be considered during the design of the carrier or the carrier.the aperture cannot be freely positioned and, in particular, the optical properties of a translucent or transparent aperture or a light guide belonging to the carrier suffer under the material-bonded connection.

[0002] A control element according to the preamble of claim 1 and an assembly method according to the preamble of the dependent method claim are known from DE 10 2016 123 118 B4. Control elements of this type are also known from DE 10 2015 217 856 A1, DE 10 2013 021 879 A1 and DE 10 2006 062 393 A1.

[0003] Against this background, there was a need for a solution for a control element with a cover and carrier and a sensor film arranged between them, which is easy to mount, but also ensures secure fixation and reproducible positioning of the sensor film. This problem is solved by a control element according to claim 1. Equally advantageous uses and a mounting method are each the subject of the dependent claims. Advantageous embodiments are each the subject of the dependent claims. It should be noted that the features listed individually in the claims can be combined with one another in any technologically meaningful way and demonstrate further embodiments of the invention. The description, especially in conjunction with the figures, further characterizes and specifies the invention.

[0004] The invention relates to a control element with a louvre that forms a viewing surface facing the user. The louvre is, for example, at least partially transparent or translucent. The louvre can be made in one or more parts and, for example, has, in addition to a louvre base, a transparent cover layer bonded to the louvre base, which is preferably made of a transparent thermoplastic and forms the viewing surface facing the user. Furthermore, the louvre can, for example, have a thermoplastic decorative film bonded to the cover layer, which is coated with a decorative coating, for example, printed, on one of its main surfaces, in particular the main surface facing the cover layer. The decorative film preferably has a transparent film substrate that is coated with a translucent to opaque finish in certain areas to form the decorative coating.

[0005] The term "viewing surface," used in reference to the surface of the control panel facing the viewer, is to be interpreted broadly: it can refer at least partially to a decorative surface designed purely for viewing, or at least partially to a touch or actuation surface facing the viewer, designed to allow user input through touch and / or actuation, thus qualifying the control element as an input device for a human-machine interface. In one embodiment, the viewing surface comprises an array of touch-sensitive surfaces. The viewing surface can also include a backlit display area. The display area and the touch or actuation surface can also be arranged congruently.

[0006] The control element according to the invention further comprises a carrier arranged on the side of the bezel facing away from the viewer. The carrier is, for example, made of a thermoplastic and serves, for example, to attach the control element to a load-bearing component of a motor vehicle. A circuit board is provided on the carrier, for example, for mounting and electrically contacting a light source intended for backlighting the display area and for electrically controlling the sensor film described below. In one embodiment, the carrier further comprises a light guide, which is provided for light distribution and / or backlighting of the at least one display area.

[0007] According to the invention, a film layer structure is provided between the carrier and the aperture. This structure comprises at least one film, for example, a sensor film for capacitive touch detection, a diffuser and / or light-guiding film, or both. The film layer structure forms at least one pair of two opposing tabs, the free ends of which point in opposite directions. The direction of extension is understood to be the direction extending from the geometric center of the base of the tab to the geometric center at the free end of the tab. For example, the free ends of the tabs of the pair can be oriented away from each other or towards each other, at least when the film layer structure is not mounted. Preferably, the free ends of the tabs, and thus the directions of extension of the pair, point towards each other.

[0008] According to the invention, the tabs of the pair each extend through a perforation surrounded by the contact surface in the direction of extension, in order to fix the film layer structure on the aperture or the carrier, depending on which of the two forms the contact surface with the perforations, at least in a direction perpendicular to the contact surface, by pairwise interaction of the tabs.

[0009] Preferably, the film layer structure borders both the substrate and the aperture. For example, the flap represents a strip-shaped film section of the film layer structure lying within its maximum outer circumference.

[0010] The carrier and aperture are fixed to one another, for example, by force-fit, form-fit, and / or material-fit connection. Preferably, the connection between the carrier and aperture is detachable. Most preferably, the carrier and aperture are connected to each other exclusively by cooperating locking elements formed on the carrier and aperture.

[0011] The term "film layer structure" is to be understood as a film layer structure comprising one film or several stacked films. The multiple films are either bonded to one another or loosely stacked. Preferably, the film layer structure includes a sensor film for capacitive touch detection. For example, this sensor film is coated with a layer of an electrically conductive material to form one or more electrically isolated electrodes for capacitive touch detection. The electrode, together with its surroundings, or the electrodes in pairs, generate an electric measuring field penetrating the contact surface, which represents an electrical measuring capacitance that is detected when a finger approaches or touches the contact surface.An input device experiences a change in measuring capacitance, which can be detected by an evaluation unit electrically connected to the electrode(s) of the sensor film. If the sensor film forms the tabs of the film layer structure, these are, for example, uncoated.

[0012] The fixed film layer assembly via the tab-through connection simplifies assembly. At the same time, this ensures precise and reproducible positioning of the film layer assembly. According to a preferred embodiment, the fixing of the film layer assembly to the carrier or aperture is detachable; that is, a material-bonded connection between the film layer assembly and the carrier or aperture is omitted according to the invention, thus enabling non-destructive replacement of the components, particularly the film layer assembly. In one embodiment, the film layer assembly further comprises a mask formed by an opaque coating on one of the films of the film layer assembly, so that the film layer assembly is only partially transparent or translucent in order to display a symbol or optical marking as a display area within the viewing surface when backlit.

[0013] Preferably, the tab of the pair, which extends through the associated opening, runs with its free end onto a stop formed on the carrier, which limits the engagement depth of the respective tab, wherein the stops for the pair of tabs are arranged in such a way that the film layer structure is fixed in a direction parallel to the contact surface without play.

[0014] Preferably, each tab of the pair is arranged within a maximum outer circumference of the film layer structure.

[0015] Preferably, each tab of the pair is formed by a, preferably continuous, die-cut cut of at least one film of the film layer structure.

[0016] Preferably, the film layer structure comprises a diffuser and / or light-guiding film for light guidance and / or light distribution. For example, the light-guiding film is made of a transparent or translucent material. For example, at least one main surface of the diffuser and / or light-guiding film is provided with a microstructure.

[0017] Preferably, the film layer structure comprises several loosely stacked films, such that an outermost film with respect to the contact surface is provided, which has the tabs. These tabs extend, for example, through a recess provided in the intermediate film(s). An intermediate film is understood to be the film that is arranged between the outermost film and the contact surface.

[0018] Preferably, however, the outermost film with respect to the contact surface extends beyond all intermediate films of the film layer structure, and the tabs are formed in the extending part of the outermost film.

[0019] Preferably, the openings belonging to the tabs of the pair are rectangular, more preferably slot-shaped.

[0020] Preferably, the openings for the pair of tabs are formed exclusively on the carrier.

[0021] Preferably, each tab of the pair has a reduced size at one extreme end of its free end compared to the maximum clear dimension of the associated opening, wherein the tab tapers continuously in transverse direction over its entire length or at least towards its end to facilitate insertion of the tab into the respective opening. For example, the tab may simply have a chamfer at its extreme end.

[0022] According to a preferred embodiment, the carrier has a light channel or a light guide, wherein the light guide at least partially forms the contact surface or the light channel terminates in the contact surface in order to backlight the aperture with a light source which is, for example, fixed to the carrier.

[0023] Preferably, the film layer structure forms at least one positioning opening, which is penetrated by a projection formed by the substrate or aperture, serving as a positioning aid. The free end of the projection extending beyond the opening serves, for example, to create a material-bonded connection between the substrate or aperture.

[0024] The invention further relates to the use of the control unit in one of the previously described embodiments in a motor vehicle.

[0025] The invention further relates to a method for assembling a control unit, comprising the following steps: In one setup step, a cover plate is provided, forming a viewing surface facing the observer. The provided cover plate is, for example, at least partially transparent or translucent. The cover plate can be made of one or more parts and, for example, has a transparent cover layer bonded to the cover plate, preferably made of a transparent thermoplastic, which forms the viewing surface facing the observer. Furthermore, the provided cover plate can, for example, have a thermoplastic decorative film bonded to the cover layer, which is coated with a decorative layer, for example, printed, on one of its main surfaces, particularly the main surface facing the cover layer.The decorative film preferably has a transparent film substrate, which is coated with a translucent to opaque finish in certain areas to form the decorative coating. The term "visible surface" is to be interpreted broadly: it can be at least partially a decorative surface designed for pure viewing, or at least partially a touch or actuation surface facing the viewer, designed to allow input by touch and / or actuation, thus qualifying the control element as an input device for a human-machine interface. In one embodiment, the visible surface forms an array of touch-sensitive surfaces. The visible surface can also include a backlit display area. The display area and the touch or actuation area can also be arranged congruently.

[0026] In a further provisioning step, a carrier is provided. This carrier is, for example, made of a thermoplastic and serves, for instance, to attach the control unit to a load-bearing component of a motor vehicle. A circuit board is provided or attached to the carrier for mounting and electrically connecting a light source intended for backlighting the display area and for electrically controlling the sensor film described below. In one embodiment, the carrier also includes a light guide for distributing light and / or backlighting the at least one display area.

[0027] In a further provisioning step of the assembly method according to the invention, a film layer structure comprising at least one film is provided, forming at least one pair of two opposing tabs whose free ends point in opposite directions of extension. The direction of extension is understood to be the direction extending from the geometric center of the base of the tab to the geometric center at the free end of the tab. For example, the free ends of the tabs of the pair can be oriented away from each other or towards each other, at least in the unassembled state of the film layer structure. Preferably, the free ends of the tabs, and thus the directions of extension of the pair, point towards each other.

[0028] The term "film layer structure" is to be understood as a film layer structure comprising one film or several stacked films. The multiple films are either bonded to one another or loosely stacked. Preferably, the film layer structure includes a sensor film for capacitive touch detection. For example, this sensor film is coated with a layer of an electrically conductive material to form one or more electrically isolated electrodes for capacitive touch detection. The electrode, together with its surroundings, or the electrodes in pairs, generate an electric measuring field penetrating the contact surface, which represents an electrical measuring capacitance that is detected when a finger approaches or touches the contact surface.An input device experiences a change in measuring capacitance, which can be detected by an evaluation unit electrically connected to the electrode(s) of the sensor film. If the sensor film forms the tabs of the film layer structure, these are, for example, uncoated.

[0029] In one fastening step of the assembly method according to the invention, the film layer assembly is fastened to the carrier or the aperture by inserting the tabs in pairs into openings surrounded by the contact surface, such that each tab extends through the opening formed in the carrier or aperture in its longitudinal direction. The film layer assembly is fixed to the contact surface at least in a direction perpendicular to the contact surface by the interaction of the tabs in pairs.

[0030] In a single assembly step, the aperture and carrier are joined so that the film layer assembly is positioned between the aperture and the carrier, and the carrier is located on the side of the aperture facing away from the viewer. Preferably, the carrier and aperture are joined exclusively by a material bond, for example, by ultrasonic welding. The fixation of the film layer assembly to the carrier or aperture by the tab-through connection simplifies assembly. At the same time, this ensures precise and reproducible positioning of the film layer assembly. According to a preferred embodiment, the fixation of the film layer assembly to the carrier or aperture is designed to be detachable; that is, a material bond between the film layer assembly and the carrier or aperture is entirely dispensed with according to the invention, thus enabling non-destructive replacement of the components, in particular the film layer assembly.

[0031] According to a preferred embodiment of the method, during insertion, the tab passing through the associated opening runs with its free end onto a stop formed on the carrier, which limits the engagement depth of the respective tab, wherein the stops for the pair of tabs are arranged in such a way that the film layer structure is fixed in a direction parallel to the contact surface without play.

[0032] According to a preferred embodiment of the method, each tab of the pair is arranged within a maximum outer circumference of the film layer structure.

[0033] According to a preferred embodiment of the method, each tab of the pair is formed by a, preferably continuous, die-cut cut of at least one film of the film layer structure.

[0034] According to a preferred embodiment of the method, the provided film layer structure comprises a diffuser and / or light-guiding film for light guidance and / or light distribution. For example, the light-guiding film is made of a transparent or translucent material. For example, at least one main surface of the diffuser and / or light-guiding film is provided with a microstructure.

[0035] According to a preferred embodiment of the method, the film layer structure comprises several loosely stacked films, such that an outermost film with respect to the contact surface is provided, which has the tabs. These tabs extend, for example, through a recess provided in the intermediate film(s). An intermediate film is understood to be the film that is arranged between the outermost film and the contact surface.

[0036] However, according to a preferred embodiment of the method, it is provided that the outermost film with respect to the application surface extends beyond all intermediate films of the film layer structure, and the tabs are each formed in the extending part of the outermost film.

[0037] According to a preferred embodiment of the method, the openings belonging to the tabs of the pair are rectangular, preferably slot-shaped.

[0038] According to a preferred embodiment of the procedure, the openings for the pair of tabs are formed exclusively on the carrier.

[0039] According to a preferred embodiment of the method, each tab of the pair has a reduced dimension at one extreme end of its free end compared to the maximum clear dimension of the associated opening, wherein the tab continuously tapers in transverse extension towards its extreme end of its free end in order to facilitate the insertion of the tab into the respective opening.

[0040] According to a preferred embodiment of the method, the carrier has a light channel or a light guide, wherein the light guide at least partially forms the contact surface or the light channel terminates in the contact surface in order to backlight the aperture with a light source which is, for example, fixed to the carrier.

[0041] According to a preferred embodiment of the method, the film layer structure forms at least one positioning opening, which is penetrated by a projection formed by the carrier or aperture as a positioning aid. The free end of the projection extending beyond the opening serves, for example, to create a material-bonded connection between the carrier or aperture.

[0042] The invention is explained in more detail with reference to the following figures. These figures are to be understood as examples only and represent merely one preferred embodiment. They show: Fig. 1 a sectional view of a first embodiment of the control unit 1 according to the invention; Fig. 2 a top view of the sensor film 4 applied to the carrier 3 of the in Fig. 1 first embodiment of the control unit 1 according to the invention; Fig. 3 a supervision of the in Fig. 1 shown carrier 3 of the first embodiment of the control unit 1 according to the invention; Fig. 4 a sectional view of a second embodiment of the control unit 1 according to the invention.

[0043] Fig. Figure 1 shows a first embodiment of the control unit 1 according to the invention. The control unit 1 comprises an aperture 2, a carrier 3, and a film layer assembly 4 arranged between the aperture 2 and the carrier 3, the film layer assembly comprising only a sensor film. The aperture 2 forms a viewing surface S facing the viewer B. The aperture 2 is transparent or translucent in aperture section 2d to provide a backlit display area with a function indicator or switching status indicator for the optical orientation of the operator B. The aperture 2 can be formed in one piece or in multiple parts and, not shown in detail here, comprises, for example, a transparent cover layer, which is bonded to the aperture base and is made of a transparent thermoplastic, forming the viewing surface S facing the viewer B.Furthermore, the aperture 2 can, for example, have a thermoplastic decorative film (not shown in detail) bonded to the cover layer, which is coated with a decorative layer, for example, printed, on one of its main surfaces, in particular the main surface facing the cover layer. The term "viewing surface" S is to be interpreted broadly: it can be at least partially a decorative surface designed purely for viewing, or at least partially a touch or actuation surface facing the viewer B, designed to allow input by touch and / or actuation, so that the control element 1 qualifies as an input device for a human-machine interface. In the embodiment shown here, the viewing surface S includes a display surface in aperture section 2d, backlit by the light L of a light source 5. The display surface and the touch or actuation surface can also be arranged congruently.

[0044] The control element 1 according to the invention further comprises a carrier 3 arranged on the side of the aperture 2 facing away from the viewer B. The carrier is, for example, made of a thermoplastic and serves, for example, to fix the control element 1 to a load-bearing component of a motor vehicle and, on the other hand, to provide a planar support for the film layer assembly 4. A circuit board (not shown) is also provided on the carrier 3, for example, for attaching and electrically contacting a light source 5 intended for backlighting the display area and for electrically controlling the electrodes 4c of the sensor film 4.2 of the film layer assembly 4, which are described below. This sensor film 4.2 is shown in the top view of the Fig. Figure 2 shows the film layer structure 4 being fixed to the carrier 3. The carrier 3 further comprises a light-guiding carrier section 3d, which is provided for light distribution and / or backlighting of the display area formed in the aperture section 2d.

[0045] As can be seen from the Fig. As shown in Figure 1, the previously mentioned film layer structure 4 is arranged between the carrier 3 and the aperture 2 and comprises only a sensor film 4.2 designed for capacitive touch detection. The film layer structure 4, and in particular its sensor film 4.2, borders the carrier 3. The term "sensor film" 4.2 is to be understood as meaning that it has a coating made of an electrically conductive material, which forms one or more electrically isolated electrodes 4c for capacitive touch detection, as described in Figure 1. Fig. Figure 2 shows that the electrode 4c with the environment, or the electrodes 4c in pairs, generate an electric measuring field penetrating the contact surface of the aperture 2, which represents an electrical measuring capacitance. When the contact surface on the viewing surface S of the aperture 2 is approached or touched by a finger or an input device, this causes a change in measuring capacitance, which can be detected by an evaluation unit (not shown) electrically connected to the electrode(s) 4c of the sensor film 4.2 of the film layer assembly 4 via the connection section 4d of the sensor film 4.2 of the film layer assembly 4.

[0046] The sensor film 4.2 of the film layer structure 4 forms a pair of two opposing tabs 4a, 4a', whose free ends 4b, 4b' point in opposite directions y, y'. The direction y, y' is defined as the direction extending from the geometric center of the base of tab 4a, 4a' to the geometric center at the free end 4b, 4b' of tab 4a, 4a'. Here, the free ends 4b, 4b' of tabs 4a, 4a', and thus the directions y, y' of the pair of tabs 4a, 4a', point towards each other.

[0047] As from Fig. 1 As can be seen, the tabs 4a, 4a' of the pair each penetrate an opening 3a, 3a' surrounded by the mounting surface A in the extension direction y, y', in order to fix the sensor film 4.2 to the carrier 4 in a direction perpendicular to the mounting surface A by pairwise interaction of the tabs 4a, 4a'.

[0048] As from Fig. As can be seen in Figure 1, the tab 4a, 4a' of the pair, which extends through the associated opening 3a, 3a', each runs with its free end 4b, 4b' onto a stop 3b, 3b' formed on the carrier 3, which limits the engagement depth of the respective tab 4a, 4a', wherein the stops 3b, 3b' for the pair of tabs 4a, 4a' are arranged in such a way that the film layer structure 4 is fixed in a direction parallel to the contact surface A without any play.

[0049] How Fig. As shown in Figure 2, each tab 4a, 4a' of the pair is formed within an outer circumference of the sensor film 4 by a continuous, die-cut section of the sensor film 4, while the openings 3a, 3a' belonging to the tabs 4a, 4a' of the pair are rectangular to slit-shaped, as shown in Figure 2. Fig. Figure 3 shows. Preferably, each tab 4a, 4a' of the pair has an undersize at one extreme end of its free end compared to the maximum clear dimension of the associated opening 3a, 3a', wherein the tab 4a, 4a' tapers continuously towards its extreme end of its free end 4b, 4b' in transverse dimension x, x' to facilitate the insertion of the tab 4a, 4a' into the respective opening 3a, 3a'.

[0050] Carrier 3 and aperture 2, on the other hand, are connected to each other exclusively by cooperating locking elements formed on carrier 3 and aperture 2 respectively, as Fig. Figure 1 shows the locking means comprising locking lugs 3c formed on the carrier 3 and locking recesses formed on the aperture 2.

[0051] The fixing of the film layer assembly 4 by the tab-through connection simplifies assembly. At the same time, the opposing orientation of the tabs 4a, 4a' ensures precise and reproducible positioning of the film layer assembly 4. Furthermore, the fixing of the film layer assembly 4 to the carrier 3 is designed to be detachable, i.e., a material-bonded connection between the film layer assembly 4 and the carrier 3 is omitted, thus enabling non-destructive replacement. For light guidance and distribution, the carrier 3 has a light guide 3b, which is overlapped by the translucent film layer assembly 4 fixed to the carrier 3 by means of the tabs 4a, thus enabling backlighting of the display area in the aperture area 2d.

[0052] Fig. Figure 4 shows a second embodiment of the control unit 1 according to the invention. The control unit 1 has an aperture 2, a carrier 3, and a film layer structure 4 arranged between the aperture 2 and the carrier 3, comprising a loose stack of a sensor film 4.2 and a diffuser and / or light guide film 4.1 functioning as a diffuser and / or light guide. The aperture 2 forms a viewing surface S facing the viewer B. The aperture 2 is transparent or translucent in aperture section 2d to allow a backlit display area with a function indicator or switching status indicator for the optical orientation of the operator B.The aperture 2 can be formed in one or more parts and, not shown in detail here, has, for example, in addition to an aperture base, a transparent cover layer made of a transparent thermoplastic, which is bonded to the aperture base and forms the viewing surface S facing the observer B. Furthermore, the aperture 2 can, for example, have a thermoplastic decorative film (not shown in detail) bonded to the cover layer, which is coated with a decorative layer, for example, printed, on one of its main surfaces, in particular the main surface facing the cover layer. The term "viewing surface" S is to be interpreted broadly: it can be at least partially a decorative surface designed purely for viewing or at least partially a contact surface facing the observer B.The operating surface is designed to allow user input through touch and / or actuation, thus qualifying the control element 1 as an input device for a human-machine interface. In the embodiment shown here, the viewing surface S includes a display area in the aperture section 2d, backlit by the light L of a light source 5. The display area and the touch or actuation surface can also be arranged congruently.

[0053] The control element 1 according to the invention further comprises a carrier 3 arranged on the side of the aperture 2 facing away from the viewer B. The carrier is, for example, made of a thermoplastic and serves, for example, to fix the control element 1 to a load-bearing component of a motor vehicle and, on the other hand, to provide a planar support for the film layer structure 4. A circuit board (not shown) is also provided on the carrier 3, for example, for mounting and electrically contacting a light source 5 intended for backlighting the display area and for electrically controlling the electrodes 4c of the sensor film 4.2 of the film layer structure 4, as described below. The carrier 3 further comprises a light-guiding light channel 3e, which is provided for illuminating the transmissive film layer structure 4 and backlighting the display area formed in the aperture section 2d.

[0054] As can be seen from the Fig. As further shown in section 4, the aforementioned film layer structure 4 is arranged between the carrier 3 and the aperture 2 and, in addition to the sensor film 4.2 designed for capacitive touch detection, has a further diffuser and / or light-guiding film 4.1, which is outermost with respect to the contact surface A. The film layer structure 4, with its sensor film 4.2, borders the carrier 3, which acts as an intermediate film. The term "sensor film" 4.2 is to be understood as having a coating of an electrically conductive material, which forms one or more electrically isolated electrodes 4c for capacitive touch detection. The electrode 4c with the surroundings, or the electrodes 4c in pairs, generate an electric measuring field penetrating the contact surface of the aperture 2, which represents an electrical measuring capacitance that is detected when a finger approaches or touches the contact surface on the viewing surface S of the aperture 2.an input device causes a change in measuring capacitance, which can be detected by an evaluation unit not shown in detail, which is electrically connected to the electrode(s) 4c of the sensor film 4.2 of the film layer structure 4 via the connection section 4d of the sensor film 4.2 of the film layer structure 4.

[0055] The diffuser and / or light-guiding foil 4.1 of the foil layer structure 4 forms a pair of two opposing tabs 4a, 4a', whose free ends 4b, 4b' point in opposite directions. The direction of extension is understood to be the direction from the geometric center of the base of the tab 4a, 4a' to the geometric center at the free end 4b, 4b' of the tab 4a, 4a'. Here, the free ends 4b, 4b' of the tabs 4a, 4a', and thus the directions of extension of the pair of tabs 4a, 4a', point towards each other.

[0056] As can be seen from Fig. 4 furthermore, the outermost film with respect to the application surface A, here the diffuser and / or light guiding film 4.1, projects beyond all intermediate films of the film layer structure 4, here the sensor film 4.2, wherein the tabs 4a, 4a' are each formed in a part of the outermost film, here the diffuser and / or light guiding film 4.1, which projects beyond the sensor film 4.2.

[0057] As from Fig. As can be seen in Figure 4, the tabs 4a, 4a' of the pair each extend through an opening 3a, 3a' surrounded by the mounting surface A in opposite directions, in order to fix the diffuser and / or light guiding film 4.1 and thus the sensor film 4.2 clamped between the diffuser and / or light guiding film 4.1 and the mounting surface A to the carrier 4 in a direction perpendicular to the mounting surface A by means of pairwise interaction of the tabs 4a, 4a'.

[0058] As from Fig. As can be seen in Figure 1, the tab 4a, 4a' of the pair, which extends through the associated opening 3a, 3a', each runs with its free end 4b, 4b' onto a stop 3b, 3b' formed on the carrier 3, which limits the engagement depth of the respective tab 4a, 4a', wherein the stops 3b, 3b' for the pair of tabs 4a, 4a' are arranged in such a way that the film layer structure 4 is fixed in a direction parallel to the contact surface A without any play.

[0059] Each tab 4a, 4a' of the pair is formed within an outer circumference of the diffuser and / or light-guiding film 4.1 by a continuous, die-cut section of the diffuser and / or light-guiding film 4.1, while the openings 3a, 3a' belonging to the tabs 4a, 4a' of the pair are rectangular to slot-shaped. Preferably, each tab 4a, 4a' of the pair has an undersized dimension at one outermost end of its free end compared to the maximum clear dimension of the associated opening 3a, 3a', wherein the tab 4a, 4a' tapers continuously in its transverse direction towards the outermost end of its free end 4b, 4b' to facilitate the insertion of the tab 4a, 4a' into the respective opening 3a, 3a'.

[0060] The film layer structure 4 further forms at least one positioning opening, which in the second embodiment shown is penetrated by a projection 3f or web formed by the carrier 3 as a positioning aid in order to fix the film layer structure 4 in two directions during pre-assembly.

[0061] Carrier 3 and aperture 2, on the other hand, are connected to each other here, among other things, by cooperating locking elements formed on carrier 3 and aperture 2 respectively, as Fig. Figure 4 shows the locking means comprising locking lugs 3c formed on the carrier 3 and locking recesses formed on the aperture 2. Additionally or alternatively, the carrier 3 and aperture 2 are mutually fixed by ultrasonic welding of the projection 3f provided on the carrier side to the aperture 2.

[0062] The fixing of the film layer assembly 4 by the tab-through connection simplifies assembly. At the same time, the opposing orientation of the tabs 4a, 4a' ensures precise and reproducible positioning of the film layer assembly 4. Furthermore, the fixing of the film layer assembly 4 to the carrier 3 is designed to be detachable, i.e., a material-bonded connection between the film layer assembly 4 and the carrier 3 is omitted, thus enabling non-destructive replacement.

Claims

[1] Control element (1) comprising: an aperture (2) that forms a viewing surface (S) facing the viewer (B); a support (3) arranged on the side of the aperture (2) facing away from the viewer (B); a film layer structure (4) arranged between the carrier (3) and the aperture (2), bearing against at least one contact surface (A) formed on the side of the carrier (3) and / or the aperture (2), comprising at least one film, characterized by, that the film layer structure (4) forms at least one pair of two oppositely arranged tabs (4a, 4a') which point with their free end (4b, 4b) in opposite directions of extension (y, y'), wherein the tab (4a, 4a') each extend through an opening (3a, 3a') surrounded by the contact surface (A) in the direction of extension (y, y') in order to fix the film layer structure (4) to the aperture (2) or the carrier (3) at least in a direction perpendicular to the contact surface (A) by pairwise interaction of the tabs (4a, 4a'). [2] Control element (1) according to claim 1, wherein the tab (4a, 4a') passing through the opening (3a, 3a') each runs with its free end (4b, 4b') onto a stop (3b, 3b') formed on the carrier (3) which limits the engagement depth of the respective tab (4a, 4a'), wherein the stops (3b, 3b') for the pair of tabs (4a, 4a') are arranged such that the film layer structure (4) is fixed in a direction parallel to the contact surface (A) without play. [3] Control element (1) according to one of the preceding claims, wherein the free ends (4b, 4b') of the tabs (4a, 4a') of a pair of tabs (4a, 4a') are aligned towards each other. [4] Control element (1) according to one of the preceding claims, wherein the tab (4a, 4a') is arranged within a maximum outer circumference of the film layer structure (4). [5] Control element (1) according to one of the preceding claims, wherein the tab (4a, 4a') is each formed by a preferably continuous die-cut of at least one film of the film layer structure (4). [6] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) comprises several films that are bonded together or loosely stacked. [7] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) comprises a sensor film (4.2) for capacitive touch detection. [8] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) comprises a diffuser and / or light guiding film (4.1) for light guiding and / or light distribution. [9] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) comprises several loosely stacked films, and an outermost film with respect to the contact surface (A) comprises the tabs (4a, 4a') and at least one intermediate film arranged between the outermost film and the contact surface (A). [10] Control element (1) according to the preceding claim, wherein the outermost film with respect to the contact surface (A) extends beyond all intermediate films of the film layer structure (4), and the tabs (4a, 4a') are each formed in an extending part of the outermost film. [11] Control element (1) according to one of the preceding claims, wherein the openings (3a, 3a') are rectangular. [12] Control element (1) according to one of the preceding claims, wherein the openings (3a, 3a') are formed exclusively on the side of the carrier (3). [13] Control element (1) according to one of the preceding claims, wherein the tab (4a, 4a') has a reduced dimension at an outermost end of its free end (4b, 4b') compared to the maximum clear dimension of the associated opening (3a, 3a'), and the tab (4a, 4a') tapers continuously towards its outermost end of its free end (4b, 4b') in transverse extension (x, x'). [14] Control element (1) according to one of the preceding claims, wherein the carrier (3) has a light channel (3e) or a light guide (3d), wherein the light guide (3d) forms at least part of the contact surface (A) or the light channel (3e) terminates in the contact surface (A). [15] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) is arranged adjacent to both the carrier (3) and the aperture (2). [16] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) forms at least one positioning opening which is penetrated by a projection (3f) formed by the carrier (3) or aperture (2) as a positioning aid. [17] Control element (1) according to one of the preceding claims, wherein the film layer structure (4) is detachably fixed to the carrier (3) and / or the aperture (2). [18] Use of the control unit (1) according to any of the preceding claims in a motor vehicle. [19] Method for assembling an operating element (1) comprising the steps: Providing an aperture (2) that forms a viewing surface (S) facing the viewer (B); Providing a carrier (3); Providing a film layer structure (4) comprising at least one film, which forms at least one pair of two oppositely arranged tabs (4a, 4a') which point with their free end (4b, 4b') in opposite directions of extension (y, y'); Applying the film layer structure (4) to a contact surface (A) formed on the carrier (3) or on the aperture (2); The film layer assembly (4) is secured by inserting the tabs (4a, 4a') in pairs into each associated opening (3a, 3a') surrounded by the contact surface (A), so that the tab (4a) extends through the opening (3a, 3a') in the direction of extension (y, y') in order to fix the film layer assembly (4) to the contact surface (A) at least in a direction perpendicular to the contact surface (A) by the paired interaction of the tabs (4a, 4a'); Joining aperture (2) and carrier (3) such that the film layer structure (4) is arranged between aperture (2) and carrier (3) and the carrier (3) is arranged on the side of aperture (2) facing away from the viewer (B), characterized by , that the fastening is effected by inserting the tabs (4a, 4a') in pairs into each associated opening (3a, 3a') surrounded by the contact surface (A), so that the tab (4a) extends through the opening (3a, 3a') in the direction of extension (y, y') in order to fix the film layer structure (4) to the contact surface (A) at least in a direction perpendicular to the contact surface (A) by the pairwise interaction of the tabs (4a, 4a'). [20] Method according to the preceding claim, wherein during insertion the tab (4a, 4a') passing through the opening (3a, 3a') each runs with its free end (4b, 4b') onto a stop (3b, 3b') formed on the carrier (3) which limits the engagement depth of the respective tab (4a, 4a'), wherein the stops (3b, 3b') for the pair of tabs (4a, 4a') are arranged after insertion of the pair such that the film layer structure (4) is fixed in a direction parallel to the contact surface (A) without play. [21] Method according to one of the two preceding claims, wherein the free ends (4b, 4b') of the tabs (4a, 4a') of a pair of tabs (4a, 4a') are aligned towards each other.

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