Steering wheel input device for motor vehicle and method for manufacturing same

Abstract

The invention relates to a steering wheel input device (3) having an input element (4) for attachment 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 to generate light (15) and couple it into the first light guide layer (5, 6, 7). The first light guide layer (5, 6, 7) comprises 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 detecting the contact, which sensor layer (16) is arranged parallel to the first light guide layer (5, 6, 7) and covers the symbol structure (21, 22, 23). The steering wheel input device (3) has an evaluation unit (26) which is designed to detect a contact in a region covering the symbol structure (21, 22, 23) and to generate at least one control signal on the basis thereof.

Description

Technical Field

[0001] The present invention relates to a steering wheel input device for a motor vehicle and a method for manufacturing such a steering wheel input device. Background Technology

[0002] In modern motor vehicles, drivers can choose to control or operate a large number of vehicle functions. For this purpose, a large number of corresponding operating elements are needed in the driver's cockpit. To assign individual operating elements or portions of operating elements to different vehicle functions, these elements are equipped with visualizations related to their functions, and therefore, corresponding symbols indicating the controlled or affected vehicle functions. Due to the large number of such symbols, the level of clarity in the cockpit is reduced. This can make it difficult for drivers to quickly identify the correct operating element or the correct point on the operating element, negatively impacting driving safety. Summary of the Invention

[0003] The purpose of this invention is to provide an input device for motor vehicles, which allows for the optional display or non-display of symbols describing the function of the input device or its current function.

[0004] This objective is achieved through the subject matter of the independent claims. Advantageous improvements and preferred embodiments are the subject matter of the dependent claims.

[0005] This invention is based on the concept of providing a light guide layer with a symbol structure in a steering wheel input device for motor vehicles. Through this light guide layer, light coupled to the light source can be decoupled to display the symbol. A touch-sensitive sensor layer covers the symbol structure, enabling the detection of touch input in a corresponding area of ​​the sensor layer.

[0006] According to one aspect of the invention, a steering wheel input device for a motor vehicle is provided. The steering wheel input device includes an input element in a steering wheel housing to be attached to the steering wheel of the motor vehicle. The input element includes a display module having a first light guide layer. The steering wheel input device includes a first light source configured and arranged to generate light and couple it into the first light guide layer. The first light guide layer includes a symbol structure for decoupling the light coupled into the first light guide layer. The input element includes a sensor layer for touch detection, which covers the symbol structure and is arranged, for example, parallel to the first light guide layer. The steering wheel input device includes an evaluation unit configured to detect a touch of the input element in the area of ​​the sensor layer covering the symbol structure, and based thereon, i.e., based on the detected touch of the input element in the area of ​​the sensor layer covering the symbol structure, generate at least one control signal.

[0007] In different 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 particularly understood as a data processing device containing at least one processing circuit. Therefore, the computing unit can process data, particularly for performing computational operations. Optionally, these also include operations for performing index access to data structures such as lookup tables (LUTs).

[0008] The computing unit may in particular include one or more computers, one or more microcontrollers and / or one or more integrated circuits, such as one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or one or more system-on-a-chip (SoCs). The computing unit may also include one or more processors, such as 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, particularly one or more digital signal processors (DSPs). The computing unit may also include physical or virtual computer groups or other types of the aforementioned units.

[0009] In different embodiments, the computing unit includes one or more hardware interfaces and / or software interfaces and / or one or more storage units.

[0010] The storage cell can be designed as volatile data memory, such as dynamic random access memory (DRAM) or static random access memory (SRAM), or as non-volatile data memory, such as read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or flash EEPROM, ferroelectric random access memory (FRAM), magnetoresistive random access memory (MRAM), or phase-change random access memory (PCRAM).

[0011] At least one additional computing unit of the motor vehicle, such as a control unit, may receive and, for example, process and / or forward at least one control signal to activate, deactivate, control, or otherwise influence one or more vehicle functions of the motor vehicle. The at least one vehicle function may, for example, include the functions of a driver assistance system, a multimedia system, a communication system, lighting equipment, a directional indicator, etc.

[0012] In some embodiments, at least one additional computing unit may be understood as part of the steering wheel input device, although the computing unit is not necessarily arranged on or in the steering wheel, or intended to be attached to or in the steering wheel.

[0013] The first light-conducting layer is specifically formed in a planar manner and can be designed as a rigid light-conducting layer, or preferably, as a thin-film light-conducting layer. The first light-conducting layer is specifically transparent, substantially transparent, or semi-transparent to visible light.

[0014] The first light source may include, for example, a light-emitting diode or be composed of light-emitting diodes.

[0015] Light coupling into the first light guide layer can occur directly using a first light source, because the light source is positioned directly at one end of the first light guide layer, thus at a lateral end or end face, and therefore the generated light can be coupled into the first light guide layer. Coupling can also occur indirectly, particularly via a separate light guide element that optically connects the light source to a corresponding side or coupling region of the first light guide layer. In this way, the first light source can also be positioned such that it is spatially distant from the first light guide layer.

[0016] The first light-conducting layer can be formed, for example, in a planar manner in the region surrounding the symbol structure and has a particularly low surface roughness, such that the coupled input light is decoupled only in the region of the symbol structure, or, if present, in the region of another symbol structure or other decoupling structure of the first light-conducting layer. In the region of the symbol structure, the first light-conducting layer can have increased surface roughness compared to a flat surface, which leads to the decoupling of the coupled input light. Specifically, the coupled input light is totally internally reflected in the region inside the first light-conducting layer outside the symbol structure or other decoupling structure, such that no decoupling occurs there, while total internal reflection in the region of the symbol structure is interfered with or interrupted by surface modification (e.g., microstructuring or roughening), and instead, light decoupling occurs in the corresponding region.

[0017] Therefore, the symbol structure can be understood as the surface structure of the first light guide layer, which has a shape representing a predetermined symbol, particularly a macroscopic shape. Due to the decoupled light, the symbol can be identified and marked by an observer, thus indicating to the observer, for example, which function will be triggered at the moment of operation of the input element.

[0018] In some embodiments, a structured symbol can be formed from the microstructure of multiple structural elements, particularly microstructural elements. The concept of macroscopic shape can be represented and understood as distinct from the shape of the individual structural elements, each of which, for example, has a microscopic shape. While the macroscopic shape of the symbol structure represents the symbol, the microscopic shapes of the individual structural elements typically do not significantly affect the macroscopic shape. The microscopic shapes of the structural elements can be determined by the methods used to manufacture the structural elements and / or can be adapted to the optical requirements for decoupling light.

[0019] The sensor light is specifically positioned on one side of the first light guide layer, where it is decoupled by a symbol structure. The sensor layer used for touch detection can also be called a touch surface, and can be designed as, for example, a capacitive touch-sensitive surface.

[0020] The touch of the input element can be a direct touch of the sensor layer. According to an embodiment, the touch can also be a touch of another layer or covering, disposed on the side of the sensor layer opposite to the first photoconductor layer. The latter can be understood as an indirect touch of the sensor layer. Unless otherwise specified, reference to "touch of the sensor layer" herein or hereinafter can refer to either a direct or indirect touch of the sensor layer.

[0021] The statement that the sensor layer covers the symbol structure can be specifically understood as the sensor layer being present and arranged at least in the input element area that displays the symbol to the observer. Therefore, the observer can press or touch the area where the symbol is displayed to control or influence the corresponding vehicle function.

[0022] The light source can be actuated, for example, by means of a control unit, so that it can selectively produce or not produce light. Therefore, it is possible to control whether the symbol is displayed as described. The control unit can be part of the evaluation unit, or vice versa, or it can be provided separately from the evaluation unit. The control unit can be part of the steering wheel input device, or in some embodiments of the steering wheel input device, it can be provided separately from the steering wheel input device.

[0023] For example, if the first light source is active, vehicle functions can only be affected or controlled by touching the area of ​​the symbol structure, thus the light couples and decouples at the symbol structure. Otherwise, for example, control of vehicle functions cannot be performed. This can be achieved by an evaluation unit of the motor vehicle or at least one additional computing unit, which is then connected to the control unit accordingly to obtain the necessary information about the on or off state of the first light source.

[0024] Using the steering wheel input device according to the invention, the display of symbols by means of the symbol structure of the first light guide layer can therefore be optionally activated or deactivated, such that activation occurs only when the corresponding vehicle function is needed or can be performed. In other cases where the aforementioned vehicle function is unavailable or unnecessary, the symbols cannot be displayed, thereby reducing the overall number of symbols displayed in the cockpit area of ​​the motor vehicle, which contributes to improved driving safety.

[0025] In at least one embodiment of the steering wheel input device, in addition to the symbol structures, the first light guide layer also includes one or more additional symbol structures, which can also decouple light coupled from the first light guide layer. Therefore, two or more different symbols can be displayed simultaneously at different lateral positions of the first light guide layer. In this case, the sensor layer also covers the additional symbol structures. The evaluation unit identifies touches on input elements, for example, in the sensor layer region covering the symbol structures or in the sensor layer region covering one of the additional symbol structures, and generates at least one control signal based on the area where the touch is detected. Therefore, different controls on vehicle functions or other vehicle functions can be achieved through touches at different points.

[0026] In various embodiments, the steering wheel housing is part of the steering wheel input device. The input element is then attached or secured to the steering wheel housing.

[0027] According to at least one embodiment, the display module includes at least one additional light guide layer. The steering wheel input device includes an additional light source for each of the at least one additional light guide layer, which in each case is configured and arranged to generate light and couple it to the respective additional light guide layer. Each of the at least one additional light guide layer includes a corresponding additional symbol structure for decoupling the light coupled to the respective additional light guide layer.

[0028] The sensor layer covers the additional symbol structure of each of the at least one additional optical guide layer. The evaluation unit is configured to: for each of the at least one additional optical guide layer, detect a touch of the sensor layer in the region covering the additional symbol structure of the corresponding optical guide layer, and based on this, and therefore based on whether a touch is detected and in which region a touch is detected, generate at least one control signal.

[0029] In other words, the at least one control signal varies depending on whether the touch covers an area of ​​a symbol structure or an area of ​​another symbol structure, and if so, which of those areas was touched. Effectively, at least one control signal is generated based on which currently displayed symbol the user touched.

[0030] The first light source and the additional light source for at least one other light guide layer can be optionally and independently activated and deactivated. Therefore, light can be coupled to only one of the light guide layers, or not coupled to any light guide layer, or coupled to multiple light guide layers, or coupled to all of them. The symbol structures of different light guide layers can be arranged one on top of another, or partially one on top of another, or overlapping. In this case, it is advantageous that multiple light sources of corresponding light guide layers including symbol structures one on top of another or overlapping each other are not activated simultaneously. Therefore, multiple symbols one on top of another will not be displayed simultaneously. However, the symbol structures of the respective light guide layers can also be arranged laterally offset from each other, and thus, in particular, not overlapping. In this case, only one light guide layer can always be supplied with light by the corresponding light source, or multiple light guide layers can be supplied with light simultaneously, so that multiple symbols can be displayed simultaneously at different lateral positions. Any combination in this respect is possible.

[0031] Each of the at least one additional optical guiding layer is arranged, for example, parallel to the first optical guiding layer. Specifically, all the optical guiding layers of the sensor layer, the first optical guiding layer, and the at least one additional optical guiding layer are arranged one on top of the other along a stacking direction perpendicular to the lateral plane in which the first optical guiding layer extends, also referred to as the layer plane. In other words, all the optical guiding layers of the sensor layer, the first optical guiding layer, and the at least one additional optical guiding layer form, for example, a layer stack in the stacking direction.

[0032] Due to the optional activation and deactivation of the corresponding light source and the resulting optional display, one or more different or different combinations of symbols are possible with the aid of the corresponding symbol structure. Thus, a large number of display options or display states with different display symbols can be realized, wherein the light source can be controlled so that only those symbols that are expected or needed in the corresponding scene are always displayed, or whose assigned functions are available accordingly.

[0033] According to at least one embodiment, at least one additional light guide layer includes a second light guide layer, and an additional light source configured and arranged to generate light and couple it into the second light guide layer is or is designated as a second light source. The input element includes a circuit carrier, wherein the first and second light sources are fastened to the circuit carrier on opposing surfaces of the circuit carrier. A portion of the circuit carrier is disposed between the first and second light guide layers.

[0034] In other words, the circuit carrier thus partially protrudes into the region between the first and second light-conducting layers, and partially protrudes beyond the first and second light-conducting layers. The first and second light sources are arranged in this projection region on the opposing surfaces of the circuit carrier. This allows for a space-saving arrangement of the first and second light sources, in which case the first and second light sources are specifically designed as light-emitting diodes. The first and second light sources can be electrically connected to the control unit via the circuit carrier. The control unit can also be positioned on the circuit carrier or another circuit carrier or at another point.

[0035] The circuit carrier is opaque or opaque to visible light, in particular. Therefore, the circuit carrier portion disposed between the first and second light guide layers can prevent or reduce unwanted light leakage at the front end or in the region where light is coupled to the light guide layer.

[0036] For example, the first and second light sources can be designed as corresponding side-emitting light-emitting diodes (LEDs). In other words, the main emission direction of the corresponding generated light is parallel to or substantially parallel to the mounting surface of the corresponding LED on the circuit carrier. In this way, a particularly compact design can be achieved.

[0037] According to at least one embodiment, the circuit carrier is designed as a flexible printed circuit board or a flexible circuit carrier.

[0038] Such flexible printed circuit boards can be, for example, thin-film printed circuit boards, which can be manufactured to be particularly thin and are therefore particularly suitable for space-saving arrangements between the first and second light-conducting layers. Furthermore, the flexible design of the circuit carrier enables flexible contact or flexible positioning of control units or other electronic components that may be connected to the circuit carrier.

[0039] According to at least one embodiment, the input element includes a circuit carrier on which a first light source is fixed. The input element includes another light guide element disposed between the first light source and the first light guide layer to couple light generated by means of the first light source into the first light guide layer.

[0040] Therefore, the first light source can be arranged such that it is spatially distant from the first light guide layer, resulting in enhanced flexibility in the spatial and structural configuration of the steering wheel input device. Similar embodiments also result in embodiments in which the steering wheel input device includes at least one additional light guide layer as described above. Corresponding additional light sources can then be similarly arranged on the circuit carrier and connected to the respective light guide layer via optional additional light guide elements.

[0041] In such an embodiment, the first light source can be designed as a top-side emitting LED, wherein the principal direction of the emitted light can be perpendicular to the mounting surface of the first light source on the circuit carrier. However, a side-emitting LED can also be used here.

[0042] According to at least one embodiment, the first light guide layer is configured as a thin-film light guide.

[0043] In such embodiments, at least one additional light-guiding layer may also be designed as a thin-film light guide in each case.

[0044] Thin-film optical guides may include plastic films, such as plastic films containing polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), or composed thereof.

[0045] Thin-film light guides can be manufactured to be much thinner than rigid light guide layers. If the light guide layer is designed as a thin-film light guide, the lateral edges of the light guide layer therefore have a smaller area than those of a rigid light guide layer. This, in turn, leads to a reduction in unwanted light escaping at the edges. By using a light guide film, unwanted light escaping or unwanted reflection of light generated by the corresponding light source can also be reduced at the point where light is coupled to the light guide layer.

[0046] In embodiments where the display module includes at least one additional light guide layer, the use of thin-film light guides is particularly advantageous because the overall thickness of the display module can be reduced in this way. Specifically, the distance between the various light guide layers, and therefore the distance between different symbol structures, is also reduced. For the observer, the effect of symbols displayed by means of different light guide layers being located at different depths is thus reduced. In other words, from the observer's perspective, the different symbols of different light guide layers are essentially located on the same plane.

[0047] According to at least one embodiment, particularly an embodiment in which the first photoconductor layer is designed as a thin-film photoconductor, the thickness of the first photoconductor layer is in the range of [0.1 mm, 0.7 mm] or in the range of [0.1 mm, 0.5 mm] or in the range of [0.01 mm, 1 mm] or in the range of [1 mm, 10 mm].

[0048] This also applies to corresponding embodiments, such as additional light-conducting layers, especially if they are designed as thin-film light-conductors.

[0049] According to at least one embodiment, the symbol structure includes multiple structural elements.

[0050] Structural elements can be implemented, for example, as recesses or protrusions in or on the surface of the corresponding photoconductive layer. Structural elements can be introduced into the corresponding photoconductive layer in various ways, such as by imprinting, stamping, laser structuring, or imprint lithography, particularly nanoimprint lithography, or even milling. Similarly, photoconductive layers with symbolic structures and corresponding structural elements can be fabricated by injection molding.

[0051] According to at least one embodiment, the lateral extension of each of the structural elements is in the range of [20 μm, 70 μm] or in the range of [20 μm, 30 μm] or in the range of [40 μm, 70 μm].

[0052] This may similarly apply to corresponding embodiments of other optical guide layer structural elements.

[0053] Lateral extension can be understood here as extension within the extension plane of the corresponding optical guide layer. Lateral extension can be particularly understood as the maximum dimension of the corresponding structural element in the mentioned direction.

[0054] On the one hand, this lateral extension enables effective optical decoupling; on the other hand, when the light source is deactivated, the symbolic structure is unrecognizable or nearly unrecognizable.

[0055] According to at least one embodiment, the structural elements in the plurality of structural elements have a corresponding lateral minimum distance between each other, which is in the range of [10 μm, 150 μm] or in the range of [10 μm, 100 μm].

[0056] In this context, the lateral minimum distance is the minimum distance that exists between the corresponding structural elements, and therefore, in particular, the minimum distance between the corresponding outer edges or outer boundaries of the structural elements.

[0057] On the one hand, this minimum lateral distance enables effective optical decoupling; on the other hand, when the light source is deactivated, the symbolic structure is unrecognizable or almost unrecognizable.

[0058] According to at least one embodiment, the depth of each of the plurality of structural elements perpendicular to the lateral extension extends in the range of [5 μm, 25 μm] or in the range of [10 μm, 20 μm].

[0059] On the one hand, this depth extension enables effective optical decoupling; on the other hand, when the light source is deactivated, the symbolic structure is unrecognizable or nearly unrecognizable.

[0060] According to at least one embodiment, the structural elements among the plurality of structural elements each have a profile in a cross section perpendicular to the laterally extending section, the profile corresponding to a circular arc, especially a semicircular arc, or an elliptical arc or a triangle, especially an isosceles triangle or an equilateral triangle.

[0061] For example, structural elements are therefore made into hemispherical, partially spherical, spherical, pyramidal, and other shapes.

[0062] In this way, effective optical decoupling can be achieved, and structural elements can be fabricated in a simple manner.

[0063] According to at least one embodiment, in the region outside the symbol structure, particularly in all regions outside the symbol structure of the first light guide layer and in all other possible regions outside the symbol structure, the light guide layer has a surface roughness of up to 150 nm or up to 100 nm.

[0064] In this way, unwanted light emission from outside the symbol structure can be reduced.

[0065] Surface roughness, also known as surface roughness, can be defined, for example, as the average roughness value or root mean square roughness.

[0066] According to at least one embodiment, the first photoconductive layer has a surface roughness of at least 400 nm or at least 500 nm in the region of the symbol structure.

[0067] In this way, efficient decoupling of light can be achieved in the region of the symbol structure, and in particular, efficient decoupling of light can be prevented on its exterior.

[0068] According to at least one embodiment, the input element includes a rigid transparent cover, wherein a sensor layer is disposed between the cover and the display module.

[0069] The cover is specifically transparent to visible light. The sensor layer and, possibly, the display module, can be mechanically secured to the transparent cover. This provides mechanical stability to the sensor layer and the display module, as well as protection against external damage.

[0070] As an alternative to or supplement to the covering, in various embodiments, the input element may include a rigid carrier, on which the display module is arranged such that the display module is located between the sensor layer and the carrier. The display module and possibly the sensor layer may be mechanically fastened to the carrier.

[0071] This method can also achieve mechanical stability of the display module or sensor layer.

[0072] According to at least one embodiment, the steering wheel input device includes a steering wheel housing, and an input element is fastened to the steering wheel housing such that the input element is located outside the steering wheel housing. An evaluation unit is arranged within the interior space of the steering wheel housing.

[0073] The steering wheel housing is opaque, light-blocking, or non-transmittable, especially to visible light. Therefore, compared to the input elements, the evaluation unit is either invisible or substantially invisible to the observer from the outside.

[0074] The steering wheel housing can, for example, form the central section of the steering wheel or be designed as an airbag housing.

[0075] According to at least one embodiment, the first light source is arranged in the internal space of the steering wheel housing.

[0076] This may similarly apply to other light sources in the corresponding embodiments.

[0077] If the first light source and / or another light source are directly located at the input element, the input element can be located outside the steering wheel housing, while the light source protrudes into or is hidden within the steering wheel housing.

[0078] According to another aspect of the invention, a steering wheel for a motor vehicle is provided, the steering wheel having a steering wheel input device according to the invention.

[0079] According to another aspect of the invention, a motor vehicle having a steering wheel according to the invention or a steering wheel input device according to the invention is proposed.

[0080] According to another aspect of the invention, a method for manufacturing a steering wheel input device according to the invention is provided. In this method, a first light guide layer is provided, and a symbolic structure is introduced into the first light guide layer by an imprinting method, a stamping method, a laser structuring method, or an imprint lithography method, particularly a nanoimprint lithography method, and / or a milling method, particularly a diamond milling method. Optionally, the light guide layer having the first symbolic structure is manufactured by injection molding.

[0081] This also applies similarly to corresponding embodiments of steering wheel input devices, used to fabricate additional light guide layers.

[0082] This manufacturing method specifically includes the assembly step of the steering wheel input device, thereby obtaining the design of the steering wheel input device according to the invention. Conventional and known assembly methods can be used for this purpose.

[0083] Other embodiments of the manufacturing method according to the invention directly follow various designs of the steering wheel input device according to the invention, and vice versa. In particular, the various features and corresponding explanations and advantages of the various embodiments of the steering wheel input device according to the invention can be similarly transferred to the corresponding embodiments of the manufacturing method according to the invention.

[0084] Further features of the invention are derived from the claims, drawings, and description of the drawings. The features and combinations of features mentioned in the foregoing description, as well as those mentioned in and / or shown in the following description of the drawings, may be included in the invention not only in the combinations specified in each case, but also in other combinations. In particular, embodiments and combinations of features that do not have all the features of the original claims may also be included in the invention. Furthermore, embodiments and combinations of features that exceed or differ from the combinations of features listed in the reverse reference of the claims may be included in the invention.

[0085] The invention will now be explained in more detail with reference to specific exemplary embodiments and related diagrams. In the drawings, elements that are the same or have the same function may be given the same reference numerals. Descriptions of the same or functionally identical elements need not be repeated in different drawings. Attached Figure Description

[0086] In the attached diagram:

[0087] Figure 1 A schematic diagram illustrating an exemplary embodiment of a steering wheel having a steering wheel input device according to the present invention is shown;

[0088] Figure 2 A schematic cross-sectional view of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0089] Figure 3 A schematic diagram of an input element of another exemplary embodiment of the steering wheel input device according to the present invention is shown in top view;

[0090] Figure 4 A schematic cross-sectional view of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0091] Figure 5 A schematic diagram illustrating the functional principle of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0092] Figure 6 A schematic diagram illustrating the functional principle of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0093] Figure 7A schematic diagram of the structural elements of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0094] Figure 8 A schematic diagram of the structural elements of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0095] Figure 9 A schematic diagram of the structural elements of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown;

[0096] Figure 10 A schematic diagram of the structural elements of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown; and

[0097] Figure 11 A schematic diagram of the structural elements of the light guide layer of another exemplary embodiment of the steering wheel input device according to the present invention is shown. Detailed Implementation

[0098] Figure 1 A steering wheel 1 having an exemplary embodiment of a steering wheel input device 3 according to the present invention is schematically shown. The steering wheel input device 3 includes an input element 4 which is attached to the steering wheel housing 2 of the steering wheel 1.

[0099] Figure 2 A schematic cross-sectional view of an exemplary embodiment of a steering wheel input device 3 according to the present invention is shown. The input element 4 includes a display module having at least one light guide layer, which in the illustrated example is a first light guide layer 5 and a second light guide layer 6. The steering wheel input device 3 includes a first light source 9, which is configured and arranged to generate light 15 (see [reference]). Figure 5 The light source 10 is coupled to the first light guide layer 5. In a corresponding embodiment with a second light guide layer 6, the steering wheel input device 3 includes a second light source 10, which is configured and arranged to generate light 15 and couple it to the second light guide layer 6. Light guide layers 5 and 6 each include symbol structures 21 and 22 (see...). Figure 5 ), which is used to decouple the light 15 that is coupled to the corresponding optical guide layers 5 and 6.

[0100] The input element 4 also includes a sensor layer 16 for touch detection, which covers the light guide layers 5 and 6, particularly the symbol structures 21 and 22. The steering wheel input device 3 includes an evaluation unit configured to detect a touch of the input element 4 in the area of ​​the sensor layer 16 covering the symbol structure 21 or the symbol structure 22, and generate at least one control signal based on the detection.

[0101] The light sources 9 and 10 can be designed as side-emitting light-emitting diodes, also known as side-emitting light-emitting diodes, arranged on the flexible circuit carrier 11, particularly on opposite surfaces of the flexible circuit carrier 11. For example, a portion of the flexible circuit carrier 11 can be arranged between the first light-guiding layer 5 and the second light-guiding layer 6.

[0102] In some embodiments, the steering wheel input device 3 further includes a transparent cover 8 that covers the light guide layers 5 and 6 and the sensor layer 16.

[0103] In this way, the input element 4 can, for example, be made completely transparent. Alternatively, a rigid carrier supporting the light guide layers 5 and 6, and thus contributing to mechanical stability, can be arranged on the side of the display module opposite the cover 8. A decorative layer or another decorative element can be arranged between the light guide layers 5 and 6 and the carrier, and then made visible from the side of the cover 8.

[0104] Figure 3 A top view of the input element 4 of another exemplary embodiment of the steering wheel input device 3 according to the present invention is shown schematically. Various symbols 12 may be displayed simultaneously or selectively by light guide layers 5, 6 and possibly additional light guide layers. These symbols 12 may indicate to the user which vehicle function is currently available or substantially available, and where the user must touch the input element 4 to control the corresponding function.

[0105] Figure 4 Two variations of the optional edge coverings for the light guide layers 5, 6 in another exemplary embodiment of the steering wheel input device 3 are schematically shown. For example, a colored layer or an in-mold manufactured layer or another opaque layer as a U-shaped layer 13 or an L-shaped layer 14 may be provided at the edges to further reduce unwanted light emission at the edges.

[0106] Figure 5 and Figure 6 The functional principle of another exemplary embodiment of the steering wheel input device 3 according to the present invention is schematically illustrated. In this example, the display module includes three light guide layers 5, 6, and 7 arranged one on top of another, and the sensor layer 16 follows the uppermost light guide layer 7, and then follows the cover 8.

[0107] In this exemplary embodiment, each of the light guide layers 5, 6, and 7 includes corresponding symbol structures 21, 22, and 23, wherein the symbol structures 21, 22, and 23 overlap or are arranged one on top of another. For each of the light guide layers 5, 6, and 7, a light source 9, 10, or 17 is provided, particularly a corresponding light-emitting diode, which can laterally couple light 15 into the associated light guide layer 5, 6, or 7. The light sources 9, 10, and 17 are arranged, for example, on corresponding circuit carriers 18, 19, and 20. Figure 5In this scenario, for example, light source 17 is activated, generating light 15, which is then coupled to the uppermost light guide layer 7. Light 15 is decoupled from the uppermost light guide layer 7 via symbol structure 23 in the direction of sensor layer 16 or cover 8, so that symbol 12 is displayed to the observer.

[0108] An observer can now touch the input element 4 in the area of ​​the overlay symbol structure 23 of the sensor layer 16 and the evaluation unit 26, which can be designed as a microcontroller and can be arranged on another printed circuit board 24, to detect, for example, the corresponding touch and generate at least one control signal based on it. The evaluation unit 26 can take into account, specifically, that only the light source 17 of the uppermost light guide layer 7 is activated during the touch, while the other light sources 9 and 10 are deactivated. Therefore, the user's intent can be fully realized.

[0109] Light sources 9, 10, and 17 can be actuated, for example, by a control unit integrated on another circuit board 24, such as in the same microcontroller as the evaluation unit 26. Light sources 9, 10, and 11 and / or sensor layer 16 can be connected to another printed circuit board 24 via connection elements 25 thereon.

[0110] exist Figure 6 In the example, the light source 17 of the uppermost light guide layer 7 and the light source 9 of the lowermost light guide layer 5 are deactivated. The light source 10 of the intermediate light guide layer 6 is activated and couples light 15 into the intermediate light guide layer 6. The coupled input light 15 is decoupled through the symbol structure 22 of the intermediate light guide layer 6, and in this way, another symbol 12 is displayed to the observer. The observer can touch the corresponding area again, and the evaluation unit 26 can generate at least one control signal based on the detected touch. However, the at least one control signal generated here is different from... Figure 5 The scenarios differ because the displayed symbol 12 and therefore the user's intent are different when touching the sensor layer 16.

[0111] Figures 7 to 11 Various options for the geometric design of structural element 27 of symbolic structure 21 of optical guide layer 5 are schematically shown. Explanation and description can be similarly transferred to symbolic structures 22 and 23 of the remaining optical guide layers 6 and 7.

[0112] Figure 7 A lateral cross-sectional view through the light guide layer 5 is shown. Structural elements are, for example, hemispherical recesses regularly arranged in the surface of the light guide layer 5.

[0113] In a specific and non-limiting example, structural element 27 may have an extension of, for example, 25 μm in the xy plane or in the x direction, and the distance between each structural element 27 is 20 μm. The depth of structural element 27 in the z direction may, for example, be 10 μm. The thickness of the light guide layer 5 may be, for example, 125 μm, 250 μm, or 480 μm, and the light guide layer 5 may be, for example, a polycarbonate layer.

[0114] In another specific, non-limiting example, the lateral extension of structural element 27 is 50 μm, and the lateral spacing of structural elements 27 is 20 μm. For example, the depth of structural element 27 can also be 20 μm. The layer thickness of the light guide layer 5 can also be 125 μm, 250 μm, or 480 μm, etc.

[0115] Figure 8 Another geometric design of structural element 27 is schematically shown in a top view, i.e., in the xy plane. Here, the structural elements 27 are shaped such that they have rectangular coverage areas, for example, with side lengths of approximately 20 μm and 11 μm, and a depth of approximately 8 μm. In this example, the thickness of the light-conducting layer 5 is specifically 100 μm. The light-conducting layer 5 can here be designed, for example, as a PMMA film.

[0116] Figure 9 Another example of structural element 27 is shown. The coverage area of ​​structural element 27 is also a quadrilateral or rectangle with rounded corners and has a side length of, for example, about 20 μm or about 12 μm.

[0117] exist Figure 10 In the example, structural elements 27 are designed as spherical shells or cones, such that they have a circular covering area, for example, with a diameter of 50 μm to 70 μm. The depth of structural elements 27 in the z-direction can be, for example, 10 μm to 20 μm, and the distance between them in the xy-plane can be, for example, 100 μm to 150 μm. Figure 11 An example of the conical structural element 27 is shown in cross-section.

Claims

1. A steering wheel input device (3) for a motor vehicle, comprising an input element (4) to be attached to a steering wheel housing (2) of the motor vehicle, wherein, - The input element (4) includes a display module having a first light guide layer (5, 6, 7), and the steering wheel input device (3) includes a first light source (9, 10, 17), which is configured and arranged to generate light (15) and couple it into the first light guide layer (5, 6, 7); - The first optical guide layer (5, 6, 7) includes symbolic structures (21, 22, 23) for decoupling the light (15) coupled to the first optical guide layer (5, 6, 7); - The input element (4) includes a sensor layer (16) for touch detection, which covers the symbol structure (21, 22, 23). and - The steering wheel input device (3) includes an evaluation unit (26) configured to detect touch of the input element (4) in the area of ​​the sensor layer (16) covering the symbol structures (21, 22, 23) and generate at least one control signal based on the detection.

2. The steering wheel input device (3) according to claim 1, wherein, - The display module includes at least one additional light guide layer (5, 6, 7); - The steering wheel input device (3) includes additional light sources (9, 10, 17) for each of the at least one additional light guide layer (5, 6, 7), the additional light sources (9, 10, 17) being configured and arranged to generate light (15) and couple it to the respective additional light guide layer (5, 6, 7); - Each of the at least one additional optical guiding layer (5, 6, 7) includes a corresponding additional symbol structure (21, 22, 23) for decoupling the light (15) coupled to the corresponding additional optical guiding layer (5, 6, 7). - The sensor layer (16) covers the additional symbol structure (21, 22, 23) of each of the at least one additional optical guiding layer (5, 6, 7). and - For each of the at least one additional light guide layer (5, 6, 7), the evaluation unit (26) is configured to detect the touch of the input element (4) in the region of the sensor layer (16) covering the additional symbol structure (21, 22, 23) of the corresponding additional light guide layer (5, 6, 7), and generate the at least one control signal based on the detection.

3. The steering wheel input device (3) according to claim 2, wherein, - The at least one additional light guide layer (5, 6, 7) includes a second light guide layer (5, 6, 7), and the additional light source (9, 10, 17) is a second light source (9, 10, 17), which is configured and arranged to generate light (15) and couple it into the second light guide layer (5, 6, 7); - The input element (4) includes 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; and - A portion 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. The steering wheel input device (3) according to claim 3, wherein, The circuit carrier (11) is designed as a flexible printed circuit board.

5. The steering wheel input device (3) according to any one of claims 1 or 2, wherein, - The input element (4) includes a circuit carrier (11), and the first light source (9, 10, 17) is fastened to the circuit carrier; and - The input element (4) includes another light guide element arranged between the first light source (9, 10, 17) and the first light guide layer (5, 6, 7) to couple light (15) generated by the first light source (9, 10, 17) into the first light guide layer (5, 6, 7).

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

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

8. The steering wheel input device (3) according to any one of the preceding claims, wherein, The symbol structure (21, 22, 23) includes multiple structural elements (27), each of which extends laterally in the range of [20 μm, 70 μm] or in the range of [20 μm, 30 μm] or in the range of [40 μm, 70 μm].

9. The steering wheel input device (3) according to claim 8, wherein, The structural elements (27) of the plurality of structural elements (27) have a corresponding minimum lateral distance between each other in the range of [10 μm, 150 μm] or in the range of [10 μm, 100 μm].

10. The steering wheel input device (3) according to any one of claims 8 or 9, wherein, The depth extension of the structural elements (27) perpendicular to the lateral extension is in the range of [5 μm, 25 μm] or in the range of [10 μm, 20 μm].

11. The steering wheel input device (3) according to any one of claims 8 to 10, wherein, Each of the multiple structural elements (27) has a profile corresponding to a circular arc, an elliptical arc, or a triangle in a cross-sectional plane perpendicular to the laterally extended section.

12. The steering wheel input device (3) according to any one of the preceding claims, wherein, - The first photoconductive layer (5, 6, 7) has a surface roughness of at most 150 nm or at most 100 nm in the region outside the symbol structure (21, 22, 23); and / or - The first photoconductive 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. The steering wheel input device (3) according to any one of the preceding claims, wherein, The input element (4) includes a rigid transparent cover (8), wherein the sensor layer (16) is arranged between the cover (8) and the display module.

14. The steering wheel input device (3) according to any one of the preceding claims, wherein, The input element (4) includes a rigid carrier, wherein the display module is arranged on the carrier such that the display module is located between the sensor layer (16) and the carrier.

15. The steering wheel input device (3) according to any one of the preceding claims, wherein, The steering wheel input device (3) includes the steering wheel housing (2) and - The input element (4), which 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 inside the steering wheel housing (2).

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

18. A method for manufacturing a steering wheel input device (3) according to any one of claims 1 to 17, wherein, - Provide the first light guide layer (5, 6, 7), and introduce the symbol structure (21, 22, 23) into the first light guide layer (5, 6, 7) by means of an imprinting method, a stamping method, a laser structuring method, an imprint lithography method, and / or a milling method; or - The light guide layer (5, 6, 7) having the first symbol structure (21, 22, 23) is manufactured by injection molding.

Images