Steering wheel input device for a motor vehicle, and method for producing same

Abstract

The invention relates to a steering wheel input device (3) having an input element (4) for attaching to a steering wheel housing (2). The input element (4) has a display module with a first light guide layer (5, 6, 7), and the steering wheel input device (3) has a first light source (9, 10, 17) which is designed and arranged so as to generate light (15) and couple same into the first light guide layer (5, 6, 7). The first light guide layer (5, 6, 7) has a symbol structure (21, 22, 23) for coupling out the light (15) coupled into the first light guide layer (5, 6, 7). The input element (4) has a sensor layer (16) in order to detect a contact, said sensor layer being arranged parallel to the first light guide layer (5, 6, 7) and covering the symbol structure (21, 22, 23). The steering wheel input device (3) has an analysis unit (26) which is designed to detect a contact in a region covering the symbol structure (21, 22, 23) and generate at least one control signal on the basis thereof.

Description

[0001] Steering wheel input device for a motor vehicle and manufacturing method

[0002] The present invention relates to a steering wheel input device for a motor vehicle and a manufacturing method for such a steering wheel input device.

[0003] In modern motor vehicles, the person driving the vehicle has the option of controlling or operating a multitude of vehicle functions. This requires a large number of corresponding control elements in the cockpit of a motor vehicle. In order to be able to assign the individual control elements or parts of the control elements to the various vehicle functions, the control elements are provided with visualisations relating to their functions, i.e. with corresponding symbols that indicate the vehicle function being controlled or influenced. Due to the large number of such symbols, this leads to reduced clarity in the cockpit. This in turn can lead to the person driving the vehicle having difficulty quickly identifying the correct control element or the correct location on the control element, which has a negative impact on driving safety.

[0004] It is an object of the present invention to provide an input device for a motor vehicle in which a symbol indicating the function of the input device or a current function of the input device can be selectively displayed or not displayed.

[0005] This problem is solved by the subject matter of the independent claim. Advantageous further developments and preferred embodiments are the subject matter of the dependent claims.

[0006] The invention is based on the idea of ​​providing a steering wheel input device for a motor vehicle with a light guide layer having a symbol structure through which light coupled into the light guide layer by means of a light source can be coupled out in order to display the symbol. A touch-sensitive sensor layer covers the symbol structure so that an input can be detected by touching the corresponding area of ​​the sensor layer. According to one aspect of the invention, a steering wheel input device for a motor vehicle is specified. The steering wheel input device has an input element for attachment to a steering wheel housing of a steering wheel of the motor vehicle. The input element has a display module with a first light guide layer. The steering wheel input device has a first light source which is designed and arranged to generate light and to couple it into the first light guide layer.The first optical fiber layer has a symbol structure for coupling out the light coupled into the first optical fiber layer. The input element has a sensor layer for touch detection, which covers the symbol structure and is arranged, for example, parallel to the first optical fiber layer. The steering wheel input device has an evaluation unit configured to detect a touch of the input element in a region of the sensor layer covering the symbol structure and, based thereon, i.e., based on the detected touch of the input element in the region of the sensor layer covering the symbol structure, to generate at least one control signal.

[0007] In various embodiments of the steering wheel input device, the evaluation unit can be understood as a computing unit or part of a computing unit. A computing unit can be understood, in particular, as a data processing device that contains at least one processing circuit. The computing unit can therefore, in particular, process data to perform computing operations. This may also include operations for performing indexed access to a data structure, for example, a look-up table (LUT).

[0008] The computing unit may, in particular, contain one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or one or more single-chip systems (SoCs). The computing unit may also contain one or more processors, for example, one or more microprocessors, one or more central processing units (CPUs), one or more graphics processing units (GPUs), and / or one or more signal processors, in particular one or more digital signal processors (DSPs). The computing unit may also include a physical or virtual network of computers or other of the aforementioned units.In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more memory units.

[0009] A memory unit can be a volatile data memory, for example a dynamic random access memory (DRAM) or a static random access memory (SRAM), or a non-volatile data memory, for example a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory or flash EEPROM, a ferroelectric random access memory (FRAM), a magnetoresistive random access memory,MRAM (magnetoresistive random access memory) or phase-change random access memory (PCRAM).

[0010] At least one further computing unit, for example, control units, of the motor vehicle can receive the at least one control signal and, for example, process and / or forward it in order to activate, deactivate, control, or otherwise influence one or more vehicle functions of the motor vehicle. The at least one vehicle function can, for example, include a function of a driver assistance system of the motor vehicle, a multimedia system of the motor vehicle, a communication system of the motor vehicle, a lighting device of the motor vehicle, a turn signal, and so on.

[0011] In some embodiments, the at least one further computing unit may be considered part of the steering wheel input device, although the computing unit is not necessarily arranged on or in the steering wheel or is intended to be mounted on or in the steering wheel.

[0012] The first optical fiber layer is particularly flat and can be designed as a rigid optical fiber or, preferably, as a film optical fiber. The first optical fiber layer is particularly transparent or substantially transparent or transflective to visible light.

[0013] The first light source may, for example, include or consist of a light-emitting diode.

[0014] The coupling of the light into the first optical fiber layer by means of the first light source can occur directly, in particular by arranging the light source directly at one end, i.e., a lateral end or end face, of the first optical fiber layer, thus coupling the generated light into the first optical fiber layer. The coupling can also occur indirectly, in particular via a further optical fiber element that optically connects the light source to a corresponding side or coupling region of the first optical fiber layer. In this way, the first light source can also be arranged spatially remote from the first optical fiber layer.

[0015] The first optical fiber layer can, for example, be flat in areas surrounding the symbol structure and, in particular, have a very low surface roughness, so that the coupled-in light is only coupled out in the area of ​​the symbol structure or, if present, in areas of additional symbol structures or other coupling-out structures of the first optical fiber layer. In the area of ​​the symbol structure, the first optical fiber layer can have a surface roughness that is increased compared to the flat surface, which then leads to the coupling-out of the coupled-in light.In particular, the coupled-in light within the first optical fiber layer is totally reflected in areas outside the symbol structure or the other coupling-out structures or further symbol structures, so that coupling-out does not occur there, whereas the total reflection in the area of ​​the symbol structure is disturbed or interrupted by a surface modification, for example microstructuring or roughening, and instead coupling-out of the light occurs in the corresponding area.

[0016] The symbol structure can therefore be understood as a surface structure of the first optical fiber layer with a shape, in particular a macroscopic shape, which represents a predetermined symbol. The symbol can be recognized and identified by an observer based on the output light, so that the observer can be shown which function would be triggered, for example, at the moment by actuating the input element. In some embodiments, the symbol structure can be formed from a microstructure of several structural elements, in particular microstructure elements. The term "macroscopic shape" can be understood in contrast to the shape of the individual structural elements, which can each have a microscopic shape, for example.While the macroscopic shape of the symbol structure represents the symbol, the microscopic shapes of the individual structural elements generally do not significantly influence the macroscopic shape. The microscopic shape of the structural elements can be determined by the process used to manufacture the structural elements and / or adapted to the optical requirements for coupling out the light.

[0017] The sensor layer is arranged, in particular, on a side of the first optical fiber layer in the direction in which the light is coupled out by the symbol structure. The sensor layer for touch detection can also be referred to as a touch surface and can be configured, for example, as a capacitive touch-sensitive surface or the like.

[0018] The touch of the input element can be a direct touch of the sensor layer. Depending on the embodiment, the touch can also be a touch of another layer, a cover, or the like, which is arranged on a side of the sensor layer facing away from the first optical fiber layer. The latter can be understood as an indirect touch of the sensor layer. Reference here or below to a touch of the sensor layer can refer to a direct or indirect touch of the sensor layer, unless otherwise stated.

[0019] The fact that the sensor layer covers the symbol structure can be understood in particular as meaning that the sensor layer is present and arranged at least in the area of ​​the input element in which the symbol is displayed to the viewer. The viewer can thus press or touch the area of ​​the displayed symbol to control or influence the corresponding vehicle function.

[0020] The light source can be controlled, for example, by a control unit so that it can selectively generate or not generate the light. Accordingly, it can be controlled whether the symbol is displayed as described or not. The control unit can be part of the evaluation unit or vice versa, or can be provided separately from the evaluation unit. The control unit can be part of the steering wheel input device or, in some embodiments, can be

[0021] Steering wheel input device may be provided separately from the steering wheel input device.

[0022] For example, the vehicle function can only be influenced or controlled by touching the area of ​​the symbol structure if the first light source is active, i.e., the light is coupled in and out at the symbol structure. Otherwise, the control of the vehicle function can be omitted, for example. This can be implemented by the evaluation unit or the at least one further processing unit of the motor vehicle, with the evaluation unit or the at least one further processing unit then being connected to the control unit to obtain the required information about the on or off state of the first light source.

[0023] With the steering wheel input device according to the invention, the display of the symbol can be selectively activated or deactivated using the symbol structure of the first optical fiber layer, so that activation can only occur, for example, when the corresponding vehicle function is required or feasible. Thus, in other situations in which the aforementioned vehicle function is not available or required, the symbol can be omitted, so that the total number of displayed symbols in the cockpit area of ​​the motor vehicle can be reduced, which contributes to increased driving safety.

[0024] In at least one embodiment of the steering wheel input device, the first optical fiber layer, in addition to the symbol structure, has one or more additional symbol structures that can also couple the coupled-in light out of the first optical fiber layer. Thus, two or more different symbols can be displayed simultaneously at different lateral positions of the first optical fiber layer. The sensor layer also covers the additional symbol structures. The evaluation unit detects, for example, a touch of the input element in the region of the sensor layer covering the symbol structure or in a region of the sensor layer covering one of the additional symbol structures and generates the at least one control signal depending on in which of the said regions the touch was detected.Accordingly, touching different locations allows for different control of the vehicle's function or other vehicle functions. In various embodiments, the steering wheel housing is part of the steering wheel input device. The input element is then attached to or secured to the steering wheel housing.

[0025] According to at least one embodiment, the display module has at least one further optical fiber layer. The steering wheel input device has a further light source for each further optical fiber layer of the at least one further optical fiber layer, each of which is configured and arranged to generate light and couple it into the respective further optical fiber layer. Each further optical fiber layer of the at least one further optical fiber layer has a respective further symbol structure for coupling out the light coupled into the respective further optical fiber layer.

[0026] The sensor layer covers the further symbol structure of each further optical fiber layer of the at least one further optical fiber layer. The evaluation unit is configured to detect, for each further optical fiber layer of the at least one further optical fiber layer, a contact of the sensor layer in an area covering the further symbol structure of the respective optical fiber layer and to generate the at least one control signal based on this, i.e., based on whether and in which of the said areas the contact was detected.

[0027] In other words, the at least one control signal differs depending on whether the area covering the symbol structure or an area covering one of the other symbol structures is touched, and if so, which of these areas. Effectively, the at least one control signal is generated depending on which currently displayed symbol is touched by the user.

[0028] The first light source and the additional light sources for the at least one further optical fiber layer can be selectively and independently activated and deactivated. Thus, light may be coupled into only one of the optical fiber layers, or into none, several, or all of them. The symbol structures of the different optical fiber layers can be arranged one above the other, partially above the other, or overlapping. In this case, it is advantageous if multiple light sources of corresponding optical fiber layers that have superimposed or overlapping symbol structures are not activated simultaneously.

[0029] Accordingly, multiple superimposed symbols are not displayed simultaneously. However, it is also possible for symbol structures of the individual light guide layers to be arranged laterally offset from one another, i.e., not to overlap. In this case, only one of the light guide layers can be supplied with light from the corresponding light source at a time, or several can be supplied simultaneously, allowing multiple symbols to be displayed simultaneously at different lateral positions. Any combination of these is possible.

[0030] Each additional optical fiber layer of the at least one additional optical fiber layer is arranged, for example, parallel to the first optical fiber layer. In particular, the sensor layer, the first optical fiber layer, and all optical fiber layers of the at least one additional optical fiber layer are arranged one above the other along a stacking direction that is perpendicular to a lateral plane in which the first optical fiber layer extends, also referred to as the layer plane. In other words, the sensor layer, the first optical fiber layer, and all optical fiber layers of the at least one additional optical fiber layer form, for example, a layer stack in the stacking direction.

[0031] By selectively activating and deactivating the corresponding light sources and the resulting optional display of one or more different or combinations of different symbols using the corresponding symbol structures, a multitude of display options or display statuses with different displayed symbols can be realized, whereby the light sources can be controlled in such a way that only those symbols are displayed that are desired or required in the corresponding scenario or whose assigned functions are available accordingly.

[0032] According to at least one embodiment, the at least one further optical fiber layer comprises a second optical fiber layer, and the further light source, which is configured and arranged to generate light and couple it into the second optical fiber layer, is a second light source or is referred to as a second light source. The input element comprises a circuit carrier, wherein the first light source and the second light source are mounted on opposite surfaces of the circuit carrier. A part of the circuit carrier is arranged between the first optical fiber layer and the second optical fiber layer.

[0033] In other words, the circuit carrier partially projects into the area between the first light guide layer and the second light guide layer and partially projects beyond the first and second light guide layers. The first light source and the second light source are arranged in this projecting area on opposite surfaces of the circuit carrier. This makes it possible to achieve a space-saving arrangement of the first light source and the second light source, which in this case are designed in particular as light-emitting diodes. The first light source and the second light source can be electrically connected to the control unit via the circuit carrier. The control unit can also be positioned on the circuit carrier or on another circuit carrier or at another location.

[0034] In particular, the circuit carrier is not transparent or opaque to visible light. Accordingly, the part of the circuit carrier arranged between the first and second light guide layers can prevent or reduce unwanted light leakage at the front ends or in the area where the light is coupled into the light guide layers.

[0035] For example, the first and second light sources can be configured as respective side-emitter LEDs. In other words, a main exit direction of the generated light is parallel or substantially parallel to a mounting surface of the respective LED on the circuit carrier. This allows for a particularly compact design.

[0036] According to at least one embodiment, the circuit carrier is designed as a flexible printed circuit board or flexible circuit carrier.

[0037] Such flexible circuit boards, which can be foil circuit boards, for example, can be made particularly thin and are therefore particularly well suited for space-saving arrangement between the first and second optical fiber layers. Furthermore, the flexible design of the circuit carrier also enables flexible contacting of the circuit carrier and flexible positioning of the control unit or other electronic components that may be connected to the circuit carrier.

[0038] According to at least one embodiment, the input element has a circuit carrier on which the first light source is attached. The input element has a further light guide element, which is arranged between the first light source and the first light guide layer in order to couple light generated by the first light source into the first light guide layer. Accordingly, the first light source can be arranged spatially remote from the first light guide layer, which leads to increased flexibility in the spatial and structural design of the steering wheel input device. Analogous embodiments also arise for implementations in which the steering wheel input device has the at least one further light guide layer as described above. The respective further light sources can then likewise be arranged on the circuit carrier and, if necessary, connected to the corresponding light guide layer via further light guide elements.

[0039] In such embodiments, the first light source can be configured as a top-emitter LED, in which case the main direction of the emitted light can be perpendicular to the mounting surface of the first light source on the circuit carrier. However, side-emitter LEDs can also be used here.

[0040] According to at least one embodiment, the first light guide layer is designed as a film light guide.

[0041] In such embodiments, the at least one further light guide layer may also be designed as a film light guide.

[0042] The film light guide can, for example, comprise a plastic film, for example a plastic film containing or consisting of polycarbonate, PC, polymethyl methacrylate, PMMA, polyvinyl alcohol, PVA, or the like.

[0043] In particular, film light guides can be designed significantly thinner than rigid light guide layers. As a result, the lateral edges of the light guide layer, when designed as a film light guide, have a smaller surface area than with rigid light guide layers. This, in turn, reduces unwanted light leakage at the edges. The use of the film light guide also reduces unwanted light leakage or unwanted reflections from the light generated by the corresponding light source at the point where the light is coupled into the light guide layer.

[0044] In embodiments in which the display module has at least one additional light guide layer, the use of film light guides is particularly advantageous because it allows the overall thickness of the display module to be reduced. In particular, the distance between the individual light guide layers and thus between the various symbol structures is also reduced. For the viewer, this reduces the effect that symbols displayed by different light guide layers are located at different depth positions. In other words, the various symbols of the different light guide layers appear to be essentially on the same plane.

[0045] According to at least one embodiment, in particular an embodiment in which the first optical fiber layer is designed as a film optical fiber, a layer thickness of the first optical fiber layer is in a range [0.1 mm, 0.7 mm] or in a range [0.1 mm, 0.5 mm] or in the range [0.01 mm, 1 mm] or in the range [1 mm, 10 mm].

[0046] In corresponding embodiments, this also applies, for example, to the respective further light guide layers, in particular if these are designed as film light guides.

[0047] According to at least one embodiment, the symbol structure comprises a plurality of structural elements.

[0048] The structural elements can be implemented, for example, as depressions or elevations in or on a surface of the corresponding optical fiber layer. The structural elements can be incorporated into the corresponding optical fiber layer in various ways, for example, by embossing, stamping, laser structuring, or imprinting lithography, in particular nanoimprinting lithography, or even milling. It is also possible to produce the optical fiber layer with the symbol structure and the corresponding structural elements by injection molding.

[0049] According to at least one embodiment, the lateral extent of the structural elements is in a range [20 pm, 70 pm] or in the range [20 pm, 30 pm] or in the range [40 pm, 70 pm].

[0050] This may apply analogously in corresponding embodiments to the structural elements of the additional optical fiber layers. The lateral extent can be understood as the extent within the plane of extension of the respective optical fiber layer. The lateral extent can be understood in particular as the maximum dimension of the corresponding structural elements in the aforementioned directions.

[0051] Such lateral extensions allow, on the one hand, effective light extraction to be achieved, and, on the other hand, the symbol structures are not or hardly recognizable when the light source is deactivated.

[0052] According to at least one embodiment, the structural elements of the plurality of structural elements have a respective lateral minimum distance from one another which lies in the range [10 pm, 150 pm] or in the range [10 pm, 100 pm].

[0053] The lateral minimum distance is the minimum distance that exists between the respective structural elements, in particular a minimum distance between the respective outer edges or outer edges of the structural elements.

[0054] Such minimum lateral distances allow, on the one hand, effective light extraction to be achieved and, on the other hand, the symbol structures are not or hardly recognizable when the light source is deactivated.

[0055] According to at least one embodiment, a depth extension of the structural elements of the plurality of structural elements perpendicular to the lateral extension is in a range [5 pm, 25 pm] or in the range [10 pm, 20 pm].

[0056] Such depth extensions allow, on the one hand, effective light extraction to be achieved and, on the other hand, the symbol structures are not or hardly recognizable when the light source is deactivated.

[0057] According to at least one embodiment, the structural elements of the plurality of structural elements each have a contour in a sectional plane perpendicular to the lateral extent, which contour corresponds to a circular arc, in particular a semicircular arc, or an elliptical arc or a triangle, in particular an isosceles or equilateral triangle.

[0058] For example, the structural elements are hemispherical, semi-spherical, conical, pyramidal, or similar. This allows for effective light extraction and allows for simple manufacturing of the structural elements.

[0059] According to at least one embodiment, the optical fiber layer has a surface roughness of at most 150 nm or at most 100 nm in a region outside the symbol structure, in particular in all regions outside the symbol structure and other symbol structures that may be present in the first optical fiber layer.

[0060] In this way, unwanted light leakage outside the symbol structure can be reduced.

[0061] The surface roughness, also called surface roughness, can be defined, for example, as the mean roughness value or root mean square roughness.

[0062] According to at least one embodiment, the first optical fiber layer has a surface roughness of at least 400 nm or at least 500 nm in the region of the symbol structure.

[0063] In this way, effective coupling of the light in the area of ​​the symbol structure can be achieved and, in particular, prevented outside of it.

[0064] According to at least one embodiment, the input element has a rigid transparent cover, wherein the sensor layer is arranged between the cover and the display module.

[0065] The cover is transparent, particularly to visible light. The sensor layer and, if applicable, the display module can be mechanically attached to the transparent cover. This provides mechanical stability for the sensor layer and the display module and protects them from external damage.

[0066] Alternatively or in addition to the cover, the input element can, in various embodiments, comprise a rigid support, with the display module arranged on the support, such that the display module is located between the sensor layer and the support. The display module and, if applicable, the sensor layer can be mechanically attached to the support. This also allows mechanical stability of the display module or the sensor layer to be achieved.

[0067] According to at least one embodiment, the steering wheel input device comprises the steering wheel housing, and the input element is attached to the steering wheel housing, so that the input element is located outside the steering wheel housing. The evaluation unit is arranged inside the steering wheel housing.

[0068] In particular, the steering wheel housing is opaque, non-transparent, or not transparent to visible light. Therefore, unlike the input element, the evaluation unit is not or essentially not visible to an external observer.

[0069] The steering wheel housing can, for example, form a central section of the steering wheel or be designed as an airbag housing.

[0070] According to at least one embodiment, the first light source is arranged inside the steering wheel housing.

[0071] In corresponding embodiments, this may apply analogously to the other light sources.

[0072] If the first light source and / or the further light sources are arranged directly on the input element, this can be arranged outside the steering wheel housing, whereas the light sources protrude into the steering wheel housing or are concealed by it.

[0073] According to a further aspect of the invention, a steering wheel for a motor vehicle with a steering wheel input device according to the invention is provided.

[0074] According to a further aspect of the invention, a motor vehicle is provided with a steering wheel according to the invention or a steering wheel input device according to the invention.

[0075] According to a further aspect of the invention, a manufacturing method for a steering wheel input device according to the invention is specified. The first optical fiber layer is provided, and the symbol structure is introduced into the first optical fiber layer by an embossing method, a stamping method, a laser structuring method, an embossing lithography method, in particular a nano-embossing lithography method, and / or a milling method, in particular a diamond milling method. Alternatively, the optical fiber layer with the first symbol structure is produced by an injection molding method.

[0076] This also applies analogously to the production of the further light guide layers in corresponding embodiments of the steering wheel input device.

[0077] The manufacturing method includes, in particular, steps for assembling the steering wheel input device to produce the steering wheel input device according to the invention. Conventional and known assembly methods can be used for this purpose.

[0078] Further embodiments of the manufacturing method according to the invention follow directly from the various embodiments of the steering wheel input device according to the invention, and vice versa. In particular, individual features and corresponding explanations as well as advantages relating to the various embodiments of the steering wheel input device according to the invention can be transferred analogously to corresponding embodiments of the manufacturing method according to the invention.

[0079] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures can be encompassed by the invention not only in the respectively specified combination, but also in other combinations. In particular, the invention can also encompass embodiments and combinations of features that do not have all the features of an originally formulated claim. Furthermore, the invention can encompass embodiments and combinations of features that go beyond the combinations of features set out in the backreferences to the claims or deviate from them.

[0080] The invention is explained in more detail below using specific embodiments and associated schematic drawings. In the figures, identical or functionally equivalent elements may be provided with the same reference numerals. The description of identical or functionally equivalent elements may not necessarily be repeated for different figures.

[0081] The figures show:

[0082] Fig. 1 is a schematic representation of an exemplary embodiment of a steering wheel with a steering wheel input device according to the invention;

[0083] Fig. 2 is a schematic sectional view of another exemplary embodiment of a steering wheel input device according to the invention;

[0084] Fig. 3 is a schematic representation of an input element of a further exemplary embodiment of a steering wheel input device according to the invention in plan view;

[0085] Fig. 4 is a schematic sectional view through light guide layers of further exemplary embodiments of a steering wheel input device according to the invention;

[0086] Fig. 5 is a schematic representation of a functional principle of another exemplary embodiment of a steering wheel input device according to the invention;

[0087] Fig. 6 is a schematic representation of a functional principle of another exemplary embodiment of a steering wheel input device according to the invention;

[0088] Fig. 7 is a schematic representation of structural elements of a light guide layer of a further exemplary embodiment of a steering wheel input device according to the invention;

[0089] Fig. 8 is a schematic representation of structural elements of a light guide layer of a further exemplary embodiment of a steering wheel input device according to the invention; Fig. 9 is a schematic representation of structural elements of a light guide layer of a further exemplary embodiment of a steering wheel input device according to the invention;

[0090] Fig. 10 is a schematic representation of structural elements of a light guide layer of another exemplary embodiment of a steering wheel input device according to the invention; and

[0091] Fig. 11 is a schematic representation of structural elements of a light guide layer of a further exemplary embodiment of a steering wheel input device according to the invention.

[0092] Fig. 1 shows a schematic representation of a steering wheel 1 with an exemplary embodiment of a steering wheel input device 3 according to the invention. The steering wheel input device 3 has an input element 4 for attachment to a steering wheel housing 2 of the steering wheel 1.

[0093] A schematic sectional view through an exemplary embodiment of a steering wheel input device 3 according to the invention is shown in Fig. 2. The input element 4 has a display module with at least one light guide layer, in the example shown a first light guide layer 5 and a second light guide layer 6. The steering wheel input device 3 has a first light source 9, which is designed and arranged to generate light 15 (see Fig. 5) and to couple it into the first light guide layer 5. In corresponding embodiments with the second light guide layer 6, the steering wheel input device 3 has a second light source 10, which is designed and arranged to generate light 15 and to couple it into the second light guide layer 6. The light guide layers 5, 6 each have a symbol structure 21, 22 (see Fig. 5), which serve to couple out the light 15 coupled into the respective light guide layer 5, 6.

[0094] The input element 4 also has a sensor layer 16 for touch detection, which covers the light guide layers 5, 6 and in particular the symbol structures 21, 22. The steering wheel input device 3 has an evaluation unit configured to detect a touch of the input element 4 in an area of ​​the sensor layer 16 covering the symbol structure 21 or the symbol structure 22 and to generate at least one control signal based on the detection. The light sources 9, 10 can be configured, for example, as side-emitting light-emitting diodes, also referred to as side-emitter light-emitting diodes, which are arranged on a flexible circuit carrier 11, in particular on opposite surfaces of the flexible circuit carrier 11. For example, a part of the flexible circuit carrier 11 can be arranged between the first light guide layer 5 and the second light guide layer 6.

[0095] In some embodiments, the steering wheel input device 3 also has a transparent cover 8 which covers the light guide layers 5, 6 and the sensor layer 16.

[0096] In this way, the input element 4 can, for example, be designed to be completely transparent. It is also possible for a rigid support to be provided on a side of the display module opposite the cover 8, which supports the light guide layers 5, 6 and thus contributes to mechanical stability. A decorative layer or other decorative element can also be arranged between the light guide layers 5, 6 and the support, which is then visible from the side of the cover 8.

[0097] Fig. 3 schematically shows a top view of the input element 4 of another exemplary embodiment of a steering wheel input device 3 according to the invention. Various symbols 12 can be displayed simultaneously or selectively through the optical fiber layers 5, 6 and optionally additional optical fiber layers. These symbols 12 can indicate to a user which vehicle function is currently available or generally available and where the user must touch the input element 4 to control the corresponding function.

[0098] Fig. 4 schematically shows two variants of optional edge coverings for the light guide layers 5, 6 in further exemplary embodiments of the steering wheel input device 3. For example, a colored layer or a layer produced by in-mold molding or another opaque layer as a U-shaped layer 13 or L-shaped layer 14 can be provided at the edges to further reduce unwanted light leakage at the edges.

[0099] Figures 5 and 6 schematically illustrate a functional principle of another exemplary embodiment of a steering wheel input device 3 according to the invention. In this example, the display module has three optical fiber layers 5, 6, 7 arranged one above the other, and the sensor layer 16 follows the uppermost optical fiber layer 7, in turn followed by the cover 8.

[0100] In this exemplary embodiment, each of the light guide layers 5, 6, 7 has a corresponding symbol structure 21, 22, 23, wherein the symbol structures 21, 22, 23 overlap or are arranged one above the other. For each of the light guide layers 5, 6, 7, a light source 9, 10, 17, in particular a corresponding light-emitting diode, is provided, which can couple the light 15 laterally into the associated light guide layer 5, 6, 7. The light sources 9, 10, 17 are arranged, for example, on corresponding circuit carriers 18, 19, 20. In the scenario of Fig. 5, for example, the light source 17 is activated, generates the light 15 and couples it into the uppermost light guide layer 7. The light 15 is coupled out of the uppermost light guide layer 7 by the symbol structure 23 in the direction of the sensor layer 16 or the cover 8, so that the symbol 12 is displayed to the viewer.

[0101] The viewer can now touch the input element 4 in the area of ​​the sensor layer 16 that covers the symbol structure 23, and the evaluation unit 26, which can be configured, for example, as a microcontroller and can be arranged on a further circuit board 24, detects the corresponding touch and generates the at least one control signal based thereon. When generating the at least one control signal, the evaluation unit 26 can, in particular, take into account that at the time of the touch, only the light source 17 of the uppermost optical fiber layer 7 was active and the remaining light sources 9, 10 were deactivated. This allows the user's intention to be adequately implemented.

[0102] The light sources 9, 10, 17 can be controlled, for example, via a control unit that is also integrated on the further circuit board 24, for example, in the same microcontroller as the evaluation unit 26. The light sources 9, 10, 11 and / or the sensor layer 16 can be connected to the further circuit board 24 via connecting elements 25.

[0103] In the example of Fig. 6, the light source 17 of the uppermost light guide layer 7 is deactivated, as is the light source 9 of the lowermost light guide layer 5. The light source 10 of the middle light guide layer 6 is activated and couples the light 15 into the middle light guide layer 6. The coupled light 15 is decoupled by the symbol structure 22 of the middle light guide layer 6, and in this way a different symbol 12 is displayed to the viewer. The viewer can in turn touch the corresponding area, and the evaluation unit 26 can generate the at least one control signal depending on the detected touch. However, the at least one control signal is generated differently from the scenario in Fig. 5, since the displayed symbol 12, and thus the user's intention when touching the sensor layer 16, is different.

[0104] Figures 7 to 11 schematically illustrate various options for the geometric design of structural elements 27 of the symbol structure 21 of the optical fiber layer 5. The explanations and designs can be applied analogously to the symbol structures 22, 23 of the remaining optical fiber layers 6, 7.

[0105] Fig. 7 shows a lateral sectional view through the optical fiber layer 5. The structural elements are, for example, regularly arranged hemispherical depressions in a surface of the optical fiber layer 5.

[0106] In a specific and non-limiting example, the structural elements 27 can, for example, have an extension of 25 pm in the xy plane or in the x-direction, and a distance between the individual structural elements 27 of 20 pm. The depth of the structural elements 27 in the z-direction can, for example, be 10 pm. The layer thickness of the light guide layer 5, which can be a polycarbonate layer, for example, can be 125 pm, 250 pm, or 480 pm, or the like.

[0107] In another specific, non-limiting example, the lateral extent of the structural elements 27 is 50 pm, and the structural elements 27 are laterally spaced by 20 pm. The depth of the structural elements 27 can also be 20 pm, for example. The layer thickness of the optical fiber layer 5 can also be 125 pm, 250 pm, or 480 pm, and so on.

[0108] Fig. 8 schematically shows a further geometric configuration of the structural elements 27 in a plan view, i.e. the xy plane. Here, the shape of the structural elements 27 is such that they have a rectangular base area, for example with side lengths of approximately 20 pm and approximately 11 pm, and a depth of approximately 8 pm. The thickness of the light guide layer 5 in this example is in particular 100 pm. The light guide layer 5 can be configured here, for example, as a PMMA film. Another example of the structural elements 27 is shown in Fig. 9. Here, too, the base areas of the structural elements 27 are rectangular or rectangular with rounded corners and have, for example, side lengths of approximately 20 pm and approximately 12 pm.

[0109] In the example of Fig. 10, the structural elements 27 are designed as spherical shells or cones, so that they have circular bases, for example, with a diameter of 50 pm to 70 pm. The depth in the z-direction of the structural elements 27 can be, for example, 10 pm to 20 pm, and their distance from one another in the xy plane can be, for example, 100 pm to 150 pm. Fig. 11 shows the example of the conical structural elements 27 in a cross-sectional view.

Claims

Patent claims 1. A steering wheel input device (3) for a motor vehicle, comprising an input element (4) for attachment to a steering wheel housing (2) of the motor vehicle, wherein the input element (4) has a display module with a first light guide layer (5, 6, 7), and the steering wheel input device (3) has a first light source (9, 10, 17) which is designed and arranged to generate light (15) and to couple it into the first light guide layer (5, 6, 7); the first light guide layer (5, 6, 7) has a symbol structure (21, 22, 23) for coupling out the light (15) coupled into the first light guide layer (5, 6, 7); the input element (4) has a sensor layer (16) for touch detection, which covers the symbol structure (21, 22, 23).and the steering wheel input device (3) has an evaluation unit (26) which is designed to detect a contact of the input element (4) in a region of the sensor layer (16) covering the symbol structure (21, 22, 23) and to generate at least one control signal based thereon.; 2. Steering wheel input device (3) according to claim 1, wherein the display module has at least one further light guide layer (5, 6, 7); the steering wheel input device (3) has, for each further light guide layer (5, 6, 7) of the at least one further light guide layer (5, 6, 7), a further light source (9, 10, 17), which is designed and arranged to generate light (15) and to couple it into the respective further light guide layer (5, 6, 7); each further light guide layer (5, 6, 7) of the at least one further light guide layer (5, 6, 7) has a respective further symbol structure (21, 22, 23) for coupling out the light (15) coupled into the respective further light guide layer (5, 6, 7); the sensor layer (16) covers the further symbol structure (21, 22, 23) of each further optical fiber layer (5, 6, 7) of the at least one further optical fiber layer (5, 6, 7); and the evaluation unit (26) is configured to detect, for each further optical fiber layer (5, 6, 7) of the at least one further optical fiber layer (5, 6, 7), a contact of the input element (4) in a region of the sensor layer (16) covering the further symbol structure (21, 22, 23) of the respective further optical fiber layer (5, 6, 7) and to generate the at least one control signal based thereon.

3. Steering wheel input device (3) according to claim 2, wherein the at least one further light guide layer (5, 6, 7) has a second light guide layer (5, 6, 7) and the further light source (9, 10, 17), which is configured and arranged to generate light (15) and to couple it into the second light guide layer (5, 6, 7), is a second light source (9, 10, 17); the input element (4) has a circuit carrier (11), wherein the first light source (9, 10, 17) and the second light source (9, 10, 17) are fastened to the circuit carrier (11) on opposite surfaces of the circuit carrier (11); and wherein a part of the circuit carrier (11) is arranged between the first light guide layer (5, 6, 7) and the second light guide layer (5, 6, 7).

4. Steering wheel input device (3) according to claim 3, wherein the circuit carrier (11) is designed as a flexible printed circuit board.

5. Steering wheel input device (3) according to one of claims 1 or 2, wherein the input element (4) has a circuit carrier (11) on which the first light source (9, 10, 17) is fastened; and the input element (4) has a further light guide element which is arranged between the first light source (9, 10, 17) and the first light guide layer (5, 6, 7) in order to couple light (15) generated by the first light source (9, 10, 17) into the first light guide layer (5, 6, 7).

6. Steering wheel input device (3) according to one of the preceding claims, wherein the first light guide layer (5, 6, 7) is designed as a film light guide.

7. Steering wheel input device (3) according to one of the preceding claims, wherein a layer thickness of the first light guide layer (5, 6, 7) is in the range [0.1 mm, 0.7 mm] or in the range [0.1 mm, 0.5 mm] or in the range [0.01 mm, 1 mm] or in the range [1 mm, 10 mm].

8. Steering wheel input device (3) according to one of the preceding claims, wherein the symbol structure (21, 22, 23) has a plurality of structural elements (27) whose lateral extent lies in the range [20 pm, 70 pm] or in the range [20 pm, 30 pm] or in the range [40 pm, 70 pm].

9. Steering wheel input device (3) according to claim 8, wherein the structural elements (27) of the plurality of structural elements (27) have a respective lateral minimum distance from one another which lies in the range [10 pm, 150 pm] or in the range [10 pm, 100 pm].

10. Steering wheel input device (3) according to one of claims 8 or 9, wherein a depth extension of the structural elements of the plurality of structural elements (27) perpendicular to the lateral extension lies in the range [5 pm, 25 pm] or in the range [10 pm, 20 pm].

11. Steering wheel input device (3) according to one of claims 8 to 10, wherein the structural elements (27) of the plurality of structural elements (27) each have a contour in a sectional plane perpendicular to the lateral extent which corresponds to a circular arc or an elliptical arc or a triangle.

12. Steering wheel input device (3) according to one of the preceding claims, wherein the first optical fiber layer (5, 6, 7) has a surface roughness of at most 150 nm or at most 100 nm in a region outside the symbol structure (21, 22, 23); and / or the first optical fiber layer (5, 6, 7) has a surface roughness of at least 400 nm or at least 500 nm in the region of the symbol structure (21, 22, 23).

13. Steering wheel input device (3) according to one of the preceding claims, wherein the input element (4) has a rigid transparent cover (8), wherein the Sensor layer (16) is arranged between the cover (8) and the display module.

14. Steering wheel input device (3) according to one of the preceding claims, wherein the input element (4) has a rigid support, wherein the display module is arranged on the support, so that the display module is located between the sensor layer (16) and the support.

15. Steering wheel input device (3) according to one of the preceding claims, wherein the steering wheel input device (3) comprises the steering wheel housing (2) and the input element (4) is fastened to the steering wheel housing (2) such that the input element (4) is located outside the steering wheel housing (2); and the evaluation unit (26) is arranged in an interior of the steering wheel housing (2).

16. Steering wheel input device (3) according to claim 15, wherein the first light source (9, 10, 17) is arranged inside the steering wheel housing (2).

17. Steering wheel input device (3) according to one of claims 15 or 16, wherein the steering wheel housing (2) is designed as an airbag housing (2).

18. Manufacturing method for a steering wheel input device (3) according to one of claims 1 to 17, wherein the first light guide layer (5, 6, 7) is provided and the symbol structure (21, 22, 23) is introduced into the first light guide layer (5, 6, 7) by an embossing process or a stamping process or a laser structuring process or an embossing lithography process and / or a milling process; or the light guide layer (5, 6, 7) with the first symbol structure (21, 22, 23) is produced by an injection molding process.

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