Control unit with cover and carrier and sensor film arranged between for capacitive touch detection, associated use and assembly method

Abstract

Control element (1), comprising: an aperture (2) forming a viewing surface (S) facing the viewer (B); a carrier (3) arranged on the side of the aperture (2) facing away from the viewer (B); a sensor film (4) arranged between the carrier (3) and the aperture (2) for capacitive touch detection, the sensor film forming tabs (4a) on at least two opposite edges, the tab (4a) extending through a slot-shaped opening (3a) formed in the carrier (3) or the aperture (2) along a longitudinal extension of the tab (4a) and engaging behind it with its free end (4e), the free end (4e) of the tab (4a) having an excess (4g) compared to the maximum clear dimension of the opening (3a) in a transverse extension of the tab (4a) perpendicular to the longitudinal extension, such that the free end (4e) at least undermines the respective breakthrough (3a),in each case detachably fixing the sensor film (4) to the aperture (2) or the carrier (3); characterized in that the sensor film (4) is a film layer structure with at least one layer of an electrically conductive material, which forms one or more electrically insulated electrodes for capacitive touch detection, that the tab (4a) has a reduced dimension at an outermost end (4f) of the tab (4a) compared to the maximum clear dimension of the opening (3a), and that the tab (4a) tapers continuously at its free end (4e) towards its outermost end (4f) in a transverse direction, and that the tab (4a) has an undercut (4d) on each of its opposite longitudinal edges parallel to the longitudinal direction, which are dimensioned in such a way thatthat the tab (4a) is positively engaged in the opening (3a) and that the carrier (3) and / or the aperture (2) forms a contact surface for the placement of the sensor film (4) and that the contact surface forms at least one projection (3c) which engages in a corresponding opening (4c) of the sensor film (4) adapted to a cross-section of the projection (3c) in at least one direction.

Description

[0001] The invention relates to an operating part that essentially consists of three components: a panel, a sensor film, and a carrier. While the panel has the task of providing a visually attractive visible surface with, for example, a decoration created by a decorative coating on a decorative film as a substrate, with a symbol, with one or more haptically perceptible orientation aids, and / or with a display surface to be backlit, 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, for example to detect the approach of a finger or an input device to a sensing or touch area located within the visible surface or to detect its contact.The capacitive touch sensor can, for example, be designed for spatially resolved detection, with the sensor film comprising an array of intersecting, mutually insulated electrode tracks. The carrier has the task of attaching the operating element to a supporting component, for example of a motor vehicle, such as a dashboard, a center console, and the like. It is further designed to secure the sensor film between the panel and the carrier and serves, in particular, to provide surface support for the sensor film. For a touch-sensitive operating element, reliable and precise positioning of the sensor film is crucial, since the touch sensor reacts sensitively to deviations from the predetermined distance between the sensor film and the visible surface in the direction orthogonal to the visible surface.However, reliable and reproducible positioning of the sensor film in a direction parallel to the visible surface is also important, since otherwise any optical or haptic features used to mark or delimit the corresponding contact area will no longer match the arrangement and locally varying sensitivity of the sensor film due to incorrect positioning. To avoid this problem, the sensor film is partially bonded to the panel or the carrier, for example by welding, particularly ultrasonic welding, with one of the two. This makes the assembly of the entire control unit difficult and complex, since the energy directors for ultrasonic welding, in particular, have to be taken into account in the structural design of the carrier orthe 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 from the material connection.

[0002] Against this background, there was a need for a solution for an operating part with a panel and carrier and a sensor film arranged between them, which is easier to install, but also ensures secure fixing and reproducible positioning of the sensor film. This object is achieved by an operating part according to claim 1. An equally advantageous use and an assembly method are each the subject of the independent claims. Advantageous embodiments are each the subject of the dependent claims. It should be noted that the features individually listed in the claims can be combined with one another in any technologically expedient manner and demonstrate further embodiments of the invention. The description, particularly in conjunction with the figures, further characterizes and specifies the invention.

[0003] The invention relates to an operating part with a panel that forms a visible surface facing the viewer. The panel is, for example, transparent or translucent at least in some areas. The panel can be formed from one or more parts and, for example, has, in addition to a panel lower part, a transparent cover layer that is materially bonded to the panel lower part and is preferably made of a transparent thermoplastic and forms the visible surface facing the viewer. Furthermore, the panel can, for example, have a thermoplastic decorative film that is materially bonded to the cover layer and that is coated, for example printed, with a decorative coating 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 in a translucent to opaque manner in some areas to form the decorative coating.

[0004] The term "visible surface" used in relation to the surface of the panel facing the viewer 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, which is designed to provide operating input by touch and / or actuation, so that the operating part qualifies as an input device of a human-machine interface. In one embodiment, the visible surface forms an array of touch-sensitive touch surfaces. In addition, the visible surface can also include a backlit display surface. The display surface and the touch or actuation surface can also be arranged congruently.

[0005] The control panel according to the invention further comprises a carrier arranged on the side of the panel facing away from the viewer. The carrier is made, for example, of a thermoplastic and serves, for example, to secure the control panel to a supporting component of a motor vehicle. A circuit board is provided on the carrier, for example, for fastening and electrically contacting a light source provided for backlighting the display surface and for electrically controlling the sensor film described below. In one embodiment, the carrier further comprises a light guide provided for light distribution and / or backlighting of the at least one display surface.

[0006] According to the invention, a sensor film for capacitive contact detection is provided between the carrier and the panel, which sensor film forms tabs on at least two opposite edges, wherein the tab in each case extends through a preferably slot-shaped opening formed on the carrier or on the panel in a longitudinal extent of the tab and engages behind it with its free end and / or the tab interacts positively with this opening in order to fix the sensor film to the panel or the carrier. The sensor film preferably borders both the carrier and the panel. For example, the tab in each case represents a strip-shaped film section of the sensor film protruding from an edge of a substantially rectangular base area of ​​the sensor film.

[0007] The support and panel are secured to each other, for example, by a force-fitting, form-fitting, and / or material connection. Preferably, the connection between the support and panel is detachable. Most preferably, the support and panel are connected exclusively by interacting locking means formed on the support and panel.

[0008] The term “sensor film” should be understood to mean a film layer structure comprising one film or several stacked films, wherein at least one layer is made of an electrically conductive material, which forms one or more electrically insulated electrodes for capacitive touch detection. The electrode with the environment or the electrodes in pairs generate an electrical measuring field penetrating the contact surface, which represents an electrical measuring capacitance that experiences a change in measuring capacitance when the contact surface is approached or touched with a finger or an input device. This change can be detected by an evaluation unit electrically connected to the electrode(s) of the sensor film. The tabs are preferably uncoated. Fixing the sensor film by the tab-opening connection simplifies assembly.At the same time, this ensures precise and reproducible positioning of the sensor film. According to a preferred embodiment, the sensor film is detachably attached to the carrier or panel, i.e., a materially bonded connection between the sensor film and the carrier or panel is dispensed with according to the invention, thus enabling non-destructive replacement of the components, in particular of the sensor film. In one embodiment, the sensor film further comprises a mask formed by an opaque coating, so that the sensor film is only partially transparent or translucent in order to display a symbol or an optical marking as a display area within the visible area when backlit.

[0009] Preferably, the openings for the tabs are formed exclusively on the carrier.

[0010] Preferably, the free end of the tab has an excess dimension compared to the maximum clear dimension of the opening in a transverse extension of the tab perpendicular to the longitudinal extension, so that the free end of the tab at least engages behind the respective opening.

[0011] In order to facilitate the insertion of the tab, the tab preferably has an undersize at one outermost end of the tab compared to the maximum clear dimension of the opening, wherein the tab tapers continuously at its free end towards its outermost end in a transverse extension, for example in an arrowhead shape.

[0012] According to a preferred embodiment, the tab has an undercut on each of its opposite longitudinal edges parallel to the longitudinal extension, which are jointly dimensioned such that the tab is received in the opening in a form-fitting manner in order to fix the tab in the opening with as little play as possible.

[0013] Preferably, the carrier and / or the cover form a contact surface for the sensor film to be applied, wherein the contact surface forms at least one elevation, each of which engages with a corresponding opening in the sensor film that is adapted to the cross-section of the elevation in at least one direction. This serves, for example, during assembly, to pre-position the sensor film on the contact surface before inserting the tabs. The contact surface preferably extends parallel to the visible surface. Most preferably, the visible surface and the contact surface are each curved parallel in at least one direction.

[0014] In a preferred embodiment, the carrier, as previously mentioned, has a light guide which is, for example, overlapped by the sensor film fixed to the carrier by means of the tabs in order to thus fix the light guide to the carrier.

[0015] The invention further relates to the use of the control unit in one of the previously described embodiments in a motor vehicle.

[0016] The invention further relates to a method for assembling an operating part, comprising the following steps: In a provision step, a panel is provided which forms a visible surface facing the viewer. The provided panel is, for example, transparent or translucent at least in some regions. The panel can be formed from one or more parts and, for example, in addition to a panel lower part, has a transparent cover layer which is materially bonded to the panel lower part and is preferably made of a transparent thermoplastic and forms the visible surface facing the viewer. Furthermore, the provided panel can, for example, have a thermoplastic decorative film which is materially bonded to the cover layer and which is coated, for example printed, with a decorative coating on one of its main surfaces, in particular the main surface facing the cover layer.The decorative film preferably has a transparent film substrate, which is coated in regions from translucent to opaque to form the decorative coating. The term "visible surface" 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, which is designed to make an operating input by touch and / or actuation, so that the operating part qualifies as an input device of a human-machine interface. In one embodiment, the visible surface forms an array of touch-sensitive touch surfaces. In addition, the visible surface can also include a backlit display surface. The display surface and the touch or actuation surface can also be arranged congruently.

[0017] In a further provision step, a carrier is provided. The provided carrier is made, for example, of a thermoplastic and serves, for example, to secure the control unit to a supporting component of a motor vehicle. A circuit board, for example, is provided or secured to the carrier for fastening and electrically contacting a light source provided for backlighting the display surface and for electrically controlling the sensor film described below. In one embodiment, the provided carrier further comprises a light guide provided for light distribution and / or backlighting of the at least one display surface.

[0018] In a further provision step of the assembly method according to the invention, a sensor film for capacitive touch detection is provided, which forms tabs on at least two opposite edges. The term “sensor film” should be understood to mean a film layer structure comprising one film or several stacked films, wherein at least one layer made of an electrically conductive material is provided, which forms one or more electrodes arranged electrically insulated from one another for capacitive touch detection. The electrode with the environment or the electrodes in pairs generate an electrical measuring field penetrating the contact surface, which has a measuring capacitance that when the contact surface is approached or touched with a finger oran input device experiences a change in measuring capacity, which can be detected by an evaluation unit electrically connected to the electrode(s) of the sensor foil.

[0019] In a fastening step of the assembly method according to the invention, the sensor film is fastened to the carrier or to the panel by inserting the tabs into a respective opening formed on the carrier or on the panel, so that the tab engages through the opening formed on the carrier or on the panel in a longitudinal extent of the tab and the tab engages behind the opening with its free end and / or the tab cooperates with this opening in a form-fitting manner in order to fix the sensor film to the panel or the carrier.

[0020] In a joining step, the panel and carrier are joined so that the sensor film is arranged between the panel and the carrier and the carrier is arranged on the side of the panel facing away from the viewer. The carrier and panel are preferably joined together exclusively by locking together interacting locking means which are formed on the carrier and panel. The fastening of the sensor film to the carrier or panel by the tab-opening connection simplifies assembly. At the same time, this ensures precise and reproducible positioning of the sensor film. According to a preferred embodiment, the fastening of the sensor film to the carrier or panel is detachable, i.e. a materially bonded connection of the sensor film to the carrier or panel is completely dispensed with according to the invention, so that a non-destructive replacement of the components, in particular the sensor film, is possible.

[0021] According to a preferred variant of the assembly method according to the invention, the openings are formed exclusively on the carrier.

[0022] According to a preferred variant of the assembly method according to the invention, the free end of the tab has an excess dimension compared to the maximum clear dimension of the opening in a transverse extension of the tab perpendicular to the longitudinal extension, so that the free end of the tab at least engages behind the respective opening.

[0023] In order to facilitate the insertion of the tab, according to a preferred variant of the assembly method according to the invention, the tab has an undersize at an outermost end of the tab compared to the maximum clear dimension of the opening, wherein the tab tapers continuously at its free end towards its outermost end in the transverse extension, for example in the shape of an arrowhead.

[0024] According to a preferred embodiment of the assembly method according to the invention, the tab has an undercut on each of its opposite longitudinal edges parallel to the longitudinal extension, which are dimensioned such that the tab is received in the opening in a form-fitting manner in order to fix the tab in the opening with as little play as possible.

[0025] According to a preferred embodiment of the assembly method according to the invention, the carrier and / or the cover form a contact surface for the sensor film to be applied, wherein the contact surface forms at least one elevation, each of which is inserted into an associated opening in the sensor film, adapted in at least one direction to a cross-section of the elevation, before or simultaneously with the insertion of at least one of the last tabs. This serves, for example, during assembly, to pre-position the sensor film on the contact surface before inserting the tabs in the fastening step.

[0026] In a preferred embodiment, the carrier has a light guide which is, for example, overlapped by the sensor film fixed to the carrier by means of the tabs in order to fix the light guide to the carrier.

[0027] The invention is explained in more detail with reference to the following figures. These figures are to be understood as examples only and represent only a preferred embodiment. They show: Fig. 1 a perspective view of an embodiment of the control part 1 according to the invention; Fig. 2 a plan view of the sensor film 4 applied to the carrier 3 of the Fig. 1 shown embodiment of the control unit 1 according to the invention; Fig. 3 a detailed view of the Fig. 1 shown embodiment of the operating part 1 according to the invention, in particular the tab 4a of the sensor film 4 in cooperation with the opening 3a of the carrier 3.

[0028] Fig. 1 shows an embodiment of the operating part 1 according to the invention. The operating part 1 has a panel 2, a carrier 3, and a sensor film 4 arranged between the panel 2 and the carrier 3. The panel 2 forms a viewing surface S facing the viewer B and is curved in a U-shape here. The panel 2 is essentially transparent or translucent. The panel 2 can, as shown here, be constructed from several parts and, in addition to a panel lower part 2b, has a transparent cover layer 2a which is integrally bonded to the panel lower part 2b and is made of a transparent thermoplastic and which forms the viewing surface S facing the viewer B.Furthermore, the panel 2 can, for example, have a thermoplastic decorative film (not shown in more detail) which is materially bonded to the cover layer 2a and which is coated, for example printed, with a decorative coating on one of its main surfaces, in particular the main surface facing the cover layer 2a. The term “visible surface” S is to be interpreted broadly: it can be at least partly a decorative surface designed for pure viewing or at least partly a touch or actuation surface facing the viewer B, which is designed to carry out an operating input by touch and / or actuation, so that the operating part 1 qualifies as an input device of a human-machine interface. In the embodiment shown here, the visible surface S also includes a plurality of backlit display surfaces, as described below with reference to . Fig. 2. The display surface and the touch or actuation surface can also be arranged congruently.

[0029] The control unit 1 according to the invention further comprises a carrier 3 arranged on the side of the panel 2 facing away from the viewer B. The carrier is made of a thermoplastic, for example, and serves, for example, to fix the control unit 1 to a supporting component of a motor vehicle and, on the other hand, to provide planar support for the sensor film 4. A printed circuit board (not shown) is also provided on the carrier 3, for example, for fastening and electrically contacting a light source provided for backlighting the display surface and for electrically controlling the sensor film 4 described below. The latter is shown in the top view of the Fig. 2, wherein the sensor film 4 is fixed to the carrier 3. The carrier 3 further comprises a light guide 3a, which is provided for light distribution and / or backlighting of the multiple display surfaces 4b.

[0030] As can be seen from the Fig. 1 and Fig. 2, the previously mentioned sensor film 4 is arranged between the carrier 3 and the aperture 2 and is designed for capacitive touch detection. The sensor film 4 borders both the carrier 3 and the aperture 2. The term “sensor film” 4 should be understood to mean a film layer structure comprising a film or a plurality of stacked films, wherein at least one layer (not shown in more detail) made of an electrically conductive material is provided, which forms one or more electrodes arranged electrically insulated from one another for capacitive touch detection. The electrode with the environment or the electrodes in pairs generate an electrical measuring field penetrating the contact surface, which represents an electrical measuring capacitance that is generated when the contact surface is approached or touched with a finger oran input device causes a change in measuring capacity, which can be detected by an evaluation unit (not shown in detail) electrically connected to the electrode(s) of the sensor film 4.

[0031] The sensor film 4 forms tabs 4a on at least two opposite edges, a total of 4. The tab 4 represents a strip-shaped film section of the sensor film 4, protruding from an edge of a substantially rectangular base area of ​​the sensor film 4. The tab 4 does not have an electrically conductive coating. The tab 4a extends through a slot-shaped opening 3a formed on the carrier 3 in a longitudinal extension of the tab 4a and, as Fig. 3 shows in detail, not only does the free end 4e of the tab 4a engage behind the opening 3a, but the tab 4a also interacts with this opening 3a in a form-fitting manner in order to secure the sensor film 4 to the carrier 3. For the engagement, the free end 4e of the tab 4a has an excess dimension 4g compared to the maximum, clear dimension of the opening 3a in a transverse extent of the tab 4a perpendicular to the longitudinal extent. To facilitate the insertion of the tab 4a, the tab 4a also has an undersize at an outermost end 4f of the tab 4a compared to the maximum, clear dimension of the opening 3a, wherein the tab 4a tapers continuously at its free end 4e towards its outermost end 4f in the transverse extent, here in an arrowhead shape.For the form-fitting interaction, the tab 4a has an undercut 4d on each of its opposite longitudinal edges parallel to the longitudinal extension, which are jointly dimensioned such that the tab 4a is received in the opening 3a in a form-fitting manner in order to fix the tab 4a in the opening 3a with as little play as possible.

[0032] Carrier 3 and panel 2, however, are connected to each other exclusively by interacting locking means 5 formed on carrier 3 and panel 2, such as Fig. 1, wherein the locking means 5 are designed here such that the sensor film 4 is clamped between the carrier 3 and the aperture 2.

[0033] The fastening of the sensor foil 4 by the tab-opening connection simplifies assembly. At the same time, this ensures precise and reproducible positioning of the sensor foil 4. Furthermore, the fastening of the sensor foil 4 to the carrier 3 is designed to be detachable, meaning that a material connection between the sensor foil 4 and the carrier 3 is omitted, thus enabling non-destructive replacement. Fig. As shown in Figure 2, the sensor film 4 further comprises a mask formed by an opaque coating, so that the sensor film 4 is only partially transparent or translucent in order to display a symbol or optical marking 4b as a backlit display area within the visible area when backlit. For light guidance and distribution, the carrier 3 comprises a light guide 3b, which is overlapped by the sensor film 4, which is secured to the carrier 3 by means of the tabs 4a, in order to secure the light guide 3b to the carrier 3, particularly as a loss protection during pre-assembly.

[0034] How Fig.2, the carrier 3, here in particular its light guide 3b, forms a contact surface for the sensor film 4, which extends parallel to the visible surface S after the assembly of the operating part 1 has been completed. The contact surface forms two elevations 3c, each of which engages in a corresponding opening 4c in the sensor film 4, which opening is adapted to the cross-section of the elevation 3c in at least one direction. This serves, for example, during assembly, for the reliable, reproducible pre-positioning of the sensor film 4 on the contact surface before the insertion of the tabs 4a.

Claims

[1] Control unit (1), comprising: a diaphragm (2) forming 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 sensor film (4) for capacitive contact detection arranged between the carrier (3) and the panel (2), which forms tabs (4a) on at least two opposite edges of the sensor film (4), wherein the tab (4a) in each case extends through an opening (3a) formed on the carrier (3) or on the panel (2) in a longitudinal extension of the tab (4a) and engages behind it with its free end (4e) and / or the tab (4a) interacts positively with this opening (3a), in each case in order to fix the sensor film (4) to the panel (2) or the carrier (3). [2] Control part (1) according to claim 1, wherein the opening (3a) is slot-shaped. [3] Control unit (1) according to one of the preceding claims, wherein the openings (3a) are formed exclusively on the support (3). [4] Operating part (1) according to one of the preceding claims, wherein the free end (4e) of the tab (4a) has an excess dimension (4g) compared to the maximum clear dimension of the opening (3a) in a transverse extension of the tab (4a) perpendicular to the longitudinal extension, so that the free end (4e) at least engages behind the respective opening (3a). [5] Operating part (1) according to one of the preceding claims, wherein the tab (4a) has an undersize at an outermost end (4f) of the tab (4a) compared to the maximum clear dimension of the opening (3a) and the tab (4a) tapers continuously at its free end (4e) towards its outermost end (4f) in the transverse extension. [6] Operating part (1) according to one of the preceding claims, wherein the tab (4a) has an undercut (4d) on each of its opposite longitudinal edges parallel to the longitudinal extent, which are dimensioned such that the tab (4a) is received in the opening (3a) in a form-fitting manner. [7] Control part (1) according to one of the preceding claims, wherein the carrier (3) and / or the cover (2) forms a contact surface for the contact of the sensor film (4) and the contact surface forms at least one elevation (3c) which in each case engages in an associated opening (4c) in the sensor film (4) which is adapted to a cross-section of the elevation (3c) in at least one direction. [8] Control unit (1) according to one of the preceding claims, wherein the carrier (3) has a light guide (3b). [9] Control unit (1) according to one of the preceding claims, wherein the sensor film (4) is arranged adjacent to the carrier (3) and the panel (2). [10] Control unit (1) according to one of the preceding claims, wherein the sensor film (4) is detachably attached to the carrier (3) and / or the panel (2). [11] Use of the control unit (1) according to one of the preceding claims in a motor vehicle. [12] Method for assembling an operating part (1), comprising the steps: Providing a diaphragm (2) which forms a viewing surface (S) facing the viewer (B); Providing a carrier (3); Providing a sensor film (4) for capacitive touch detection, which forms tabs (4a) on at least two opposite edges; Fastening the sensor film (4) to the carrier (3) or to the panel (2) by inserting the tabs (4a) into a respective corresponding opening (3a) formed on the carrier (3) or on the panel (2), so that the tab (4a) reaches through the opening (3a) formed on the carrier (3) or on the panel (2) in a longitudinal extension of the tab (4a) and engages behind the opening (3a) with its free end (4a) and / or the tab (4a) cooperates with this opening (3a) in a form-fitting manner in order to fix the sensor film (4) to the panel (2) or the carrier (3); Joining the aperture (2) and the carrier (3) so that the sensor film (4) is arranged between the aperture (2) and the carrier (3) and the carrier (3) is arranged on the side of the aperture (2) facing away from the viewer (B). [13] Method according to the preceding claim, wherein the provided carrier (3) and / or the provided aperture (2) forms a contact surface for contacting the sensor film (4) and the contact surface forms at least one elevation (3c) which is inserted into an associated opening (4c) in the sensor film (4) adapted in at least one direction to a cross section of the elevation (3c) before or simultaneously with the insertion of at least one last of the tabs (4a).

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