CN115503473A - Function display and associated operating elements for optionally displaying at least one symbol representing a switching function and/or a plurality of switching states - Google Patents

Abstract

The invention relates to a functional display, comprising: a stack of photoconductors forming a display surface facing the viewer; the stack of photoconductors is formed by at least two transparent or translucent planar photoconductors arranged one above the other in the direction of the stack, The light guides are arranged as a transparent or translucent layer formed of an optically thinner material than adjacent light guides; at least one light source of each light guide is arranged to cause light to pass through the associated light guide The end face is incident into the corresponding light guide; wherein each light guide is also provided with at least one microstructured symbol area arranged in or on the light guide, comprising a plurality of microstructures and formed so that when the light source is activated by means of The illumination due to the light incident in the light guide is visible to the observer; the reflector arranged on the side of the light guide stack facing away from the observer, so that the light incident into at least one light guide and subsequently exit from the light guide light is reflected towards the observer.

Description

Optionally display at least one symbol representing the switch function and/or multiple switch states No. function displays and associated operating elements

technical field

The invention relates to a function display for selectively displaying at least one symbol representing a switching function and/or a plurality of switching states.

Background technique

These function displays are required, for example, for multifunctional operating elements in order to visualize the switching functions and/or switching states associated with the operating elements. Electronic pixel matrix displays are usually used for this purpose. They are however relatively expensive, limiting their configuration and placement due to their mostly rectangular shape. Furthermore, electronic pixel-matrix displays are often prone to "burn-in" when displaying static display content, that is, the display content is undesirably rendered even when the display is turned off due to visually perceivable damage to the imaging layers of the display remain continuously visible. Furthermore, such electronic pixel-matrix displays have a relatively high power consumption. Furthermore, in certain applications the use of conventional electronic pixel matrix displays is prohibited due to the risk of injury, for example in the event of a head impact. As an alternative to pixel-matrix displays, it is known that light from a light source impinging on an end face of an optical waveguide is emitted in a targeted manner by means of a surface structure on the main surface serving as display surface, wherein the surface structure is only provided locally area and reproduce symbols, etc. The disadvantage here is that the symbols are mostly visually inconspicuous and can therefore be easily overlooked by the observer. This leads to observers, especially the vehicle driver, for example, erroneously estimating the actual switch state.

Contents of the invention

Against this background, the object of the present invention is to provide a functional display that creates the possibility of increasing the richness of the display and thus the attention of the observer, in particular the possibility of creating depth effects by means of additional display planes and Furthermore, it can be produced cost-effectively, the functional display is energy-efficient and reliable and/or reduces the risk of injury, especially in the event of a head impact. This object is achieved by a functional display as claimed in claim 1 . Correspondingly advantageous operating elements, a steering wheel containing said functional display and an assembly formed from a plurality of functional displays are each the subject-matter of the co-located main claims. Advantageous refinements are the subject matter of the subclaims. It should be noted that the features specified individually in the claims can be combined with one another in any technically meaningful manner and reveal further configurations of the invention. The description additionally characterizes and explains the invention in detail, inter alia in conjunction with the drawings.

The invention relates to a function display for selectively displaying at least one symbol representing a switching function and/or a plurality of switching states, in particular for a motor vehicle. Selective display is not only understood as selectively displaying different symbols from a plurality of predetermined symbols, which in the solution of the present invention is achieved by selectively selecting one or more light sources from a plurality of light sources and energizing them To be realized, but also to be understood as switching the light source to visually selectively reveal the symbol to the observer by the activated backlighting or to make the symbol disappear as close as possible to the observer by turning off the backlighting.

The functional display according to the invention has an optical waveguide stack which forms a display surface facing the viewer when the functional display is installed as intended. The light guide stack is formed by at least two transparent or translucent planar light guides arranged one above the other in the stack direction, which are arranged separated by a transparent or translucent layer, preferably via an air gap On, the layer is formed from an optically thinner material than the adjacent light conductor. In this case, the light guide has a main surface facing the observer and a main surface facing away from the observer. At at least one light guide, the main face facing away from the observer faces the next adjacent light guide in the stacking direction.

The functional display according to the invention can optionally have an outer transparent or translucent cover layer arranged between the light conductor stack and the observer, through which the functional display is arranged as intended The lower display surface defined by the light conductor stack is visible to a viewer. Materials for the cover layer and light guide are, for example, plastics, preferably thermoplastics, such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile - Butadiene-styrene (ABS) or polymethylmethacrylate (PMMA), or glass material.

According to the invention, each light guide is provided with at least one light source arranged to cause light to be incident into the respective light guide via an end face of the relevant light guide. The light guide has, for example, two opposite main surfaces, preferably extending parallel to one another, which are connected via end surfaces, for example at narrow sides and at long sides of the light guide, which are connected to the The main areas of the light guide together form a common edge. The end faces are, for example, orthogonal to at least one main face or to both main faces of the light guide.

The light source is, for example, a light-emitting diode, in particular a light-emitting diode in SMD design. In order to improve the light incidence and/or to adapt the light emission characteristics of the light source to the end faces intended for light to enter the light guide, preferably a lens and/or respectively are arranged between the light guide and the light source Baffles and/or Light Channels. Baffles or light channels are for example also formed to suppress spillage of light to the viewer, other layers or light guides than the assigned light guide.

According to the invention, each light guide is also provided with a microstructured symbol area arranged in or on said light guide, said sign area comprising a plurality of light-refracting and/or light-scattering microstructures. The microstructured symbol areas alone or together with other microstructured symbol areas of the same light guide or of a further light guide form a sign due to the light generated by the plurality of microstructures at the corresponding microstructure surface Refraction and/or light scattering, the symbols become luminously visible to the observer when the light source is activated by means of the light incident into the corresponding light guide. For example, by means of the microstructure, an angle of incidence of light on the relevant main surface does not satisfy the total reflection condition of the main surface of the light guide as an interface, so that the light incident into the light guide leaves the light guide again. photoconductor.

According to the invention there is provided a preferably partially transmissive (that is to say partially transparent) mirror arranged on the side of the light guide stack facing away from the observer, which mirror is formed so that the light incident on the light guide Light in at least one of the light guides and subsequently emitted from said light guide by means of associated microstructures is reflected in the direction of the observer. The mirrors are produced, for example, by metal vapor deposition on substrates, especially transparent substrates such as foils, thermoplastic layers or layers formed from glass materials.

The depth effect of the display device can thus be realized relatively simply and cost-effectively in that the mirror provides a further display that is offset to the rear for the viewer relative to the light guides of the light guide stack. plane, the display plane is located, for example, in the virtual image plane of the mirror. This depth effect cannot be achieved with the light guide stack alone and provides additional optical appeal at the viewer.

The microstructure of the at least one microstructured light guide is preferably formed in such a way that light incident on the respective light guide exits in the direction of the observer, that is to say while bypassing the mirror. Thus, at the observer, depending on the activation of the light source, a depth effect or even a stereoscopic impression of the displayed symbol can be achieved through different display planes. This is achieved, for example, by means of a symbol field display with a mirror and a simultaneous display of the same symbol field display of the same or the other light conductor bypassing the mirror by the optical waveguide stack, wherein the parallax shift of the symbol field is to both eyes The three-dimensional nature of the displayed symbol is implied to the viewer. In another embodiment, the attention of the observer can also be attracted to On a functional display, this is achieved by changing the display plane of the functional display. By selectively activating the light source, it is relatively simple to visualize the different switching states or switching functions. Functional displays can be realized simply and cheaply and give designers a lot of design space, which also involves the arrangement of functional displays. Functional displays exhibit virtually no aging effects from light radiation and are relatively energy-efficient. Microstructuring, for example, reproduces symbols in script as images, as their inverse illustrations or as their outlines. The previously mentioned depth effect can be set, for example, by the distance between the light conductors, for example the air gap thickness. The distance is, for example, in the range of 1 to 3 mm.

The microstructured symbol areas can be introduced into the light guide by laser ablation, for example applied three-dimensionally by glass 3D painting (Vitrographie, also referred to as laser internal engraving) or on one of its main surfaces. The microstructured symbol areas are preferably formed by embossing one of the main surfaces of each light guide, whereby a functional display can be realized cost-effectively.

The microstructured symbol field is preferably formed from a plurality of microstructures formed in the same shape, which each together define a continuous microstructured symbol field per light guide. Microstructures are preferably understood to mean individual elevations on the main surface or individual depressions in the main surface. In order to substantially exclude naked-eye visibility, the largest dimension of each microstructure here is, for example, in the range of 1 to 50 μm, preferably in the range of 1 μm to 25 μm. The microstructures are preferably arranged in an evenly spaced distribution over the entire microstructured symbol area of the main surface. The microstructures are formed, for example, in the shape of pyramids or prisms. The microstructures are preferably not only uniform in shape, that is to say uniformly shaped, but also have a uniform orientation within the corresponding microstructured symbol area. For example, a consistent orientation on a flat main surface is only possible if each microstructure can be mapped onto adjacent microstructures of the same microstructured symbol area by means of an imaginary, translation-only offset . Said microstructures are more preferably formed such that they generate a collimated beam of light exiting said light guide formed by light originating from said light source and having previously entered said end face into said light guide. in the photoconductor.

^The average number density of the microstructures per microstructured symbol area of the light guide stack is preferably in the range between 500 and 7000 per mm, more preferably between 1000 and 4000 per mm in the range between ² . In this way, on the one hand, invisibility is ensured when the light source is switched off, while the impression of a uniformly illuminated symbol area can be simulated for the “naked” eye when the light source is activated. The average number density of each light guide is preferably chosen to be substantially the same, where "essentially the same" is understood to mean a maximum deviation between the number densities of the light guides of less than 100 per mm ² .

Preferably at least two directly adjacent light guides are provided, the microstructuring of which is provided only on the main surfaces facing away from each other.

All light guides outside the microstructured area are transparent and the mirrors are partially transmissive, so that a large part of the functional display remains at least partially see-through and for example ensures a see-through through the functional display for viewing Possibility for the operator to follow other displays, meters or road course through the function display. Thus, for example, a function display can be placed on the steering wheel, for example in the area between the steering wheel hub and the steering wheel ring, without affecting the viewing of the instrument panel. The proportion of all surface-structured symbol regions on the display area is preferably less than half.

The corresponding light guide does not have to be formed in one piece, it can be composed of several parts. In one refinement, the light guides each have at least one foil, such as a multilayer foil structure. The light guide is produced, for example, by back-molding a transparent foil, such as PC foil or PE foil, with a first material, especially a thermoplastic.

According to a preferred embodiment, it is provided that when viewing the display surface vertically, in particular from a position above the geometric midpoint of the display surface, the microstructured symbol areas of at least two light guides of the light guide stack are The observers are arranged non-overlapping, preferably spaced apart from one another.

According to a preferred embodiment, it is provided that when viewing the display surface vertically, in particular from a position above the geometric midpoint of the display surface, the microstructured symbol areas of at least two light guides of the light guide stack are The observers are arranged adjacent to each other, preferably overlapping, more preferably completely overlapping.

In order to provide additional color effects, according to a preferred configuration, at least two light sources differ from each other in light color.

It is preferably provided that the light guide has in each case at least one curved interface in the respective light course from the light source to the associated symbol area in order to form at least one focusing lens element. On its end faces, the light guide forms, for example, a curved light entry surface provided for the light of the light source. In another refinement, the light guide has one or more interruptions, which each have an interface functioning as a light exit surface and a light entry surface, wherein at least one interruption takes the form of an optically focusing It is curved in such a way that both interruptions are preferably curved in an optically focusing manner.

In order to avoid undesired light propagation in the respective light guide, in particular when external light is acting on it, according to a preferred embodiment, the respective light guide is provided on at least one of the end faces, preferably on the side facing the light source. The end faces facing each other have an anti-reflection coating, which is often also referred to as anti-reflection coating or compensation layer. The task of the antireflection coating is to reduce the amount of light reflected into the light guide at the coated end face relative to an uncoated end face, e.g. by absorbing light in the coating. An anti-reflection coating can be applied circumferentially, for example, in addition to the light incidence area provided for the light of the light source. The antireflection coating has, for example, an optical refractive index which is between air and the material of the light guide or the obscuring layer in value.

The invention also relates to an assembly formed from a plurality of functional displays, each of which is formed in one of the previously described embodiments. The unique feature of the assembly is the multiple display surfaces arranged next to each other from the viewer's point of view. In the assembly, at least the cover layer and/or at least one light guide are integrally formed, for example to form a common cover layer or a common light guide. In order to suppress the crosstalk of light from the light conductors of one functional display into the light conductors of the other functional displays of the assembly despite the integration, for example interruptions are provided which are made of a material corresponding to the light conductors Optically thinner material such as air is filled.

The invention also relates to an operating element with a functional display formed in one of the previously described embodiments. The operating element has, for example, a leg for fastening the operating element on a vehicle component such as a dashboard, a trim panel of a passenger compartment or in particular a steering wheel of a motor vehicle. The operating element according to the invention also has, for example, an operating part which delimits the operating surface and is formed as at least one self-supporting lever arm. The self-supporting lever arm is mounted, for example on one side, on the leg by means of a solid joint in order to be able to pivot the actuating part against a restoring force relative to the leg about an imaginary pivot axis under an actuating force acting perpendicularly to the actuating surface pivot. For example means are also provided to detect the degree of pivoting between the operating part and the leg. A solid hinge is generally referred to as the region of a member that, through bending, allows pivoting between two rigid body regions. Play-free and thus rattle-free mounting of the actuating part on the leg is achieved by the solid joint. The legs and operating parts are formed, for example, from thermoplastics such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile- Butadiene-styrene (ABS) or polymethylmethacrylate (PMMA). The operating element according to the invention is particularly suitable for configurations in which the maximum pivoting degree from the unactuated rest position around the imaginary pivot axis to the actuated maximum pivoting position is less than 10°, preferably less than 5°.

The display surface is preferably a translucent or transparent region of the operating element which is defined as the operating surface of the operating element for contacting or actuating.

The invention also relates to a steering wheel having, for example, a steering wheel hub, at least one steering wheel spoke and a steering wheel rim carried by the steering wheel spoke. The steering wheel according to the invention also has a functional display formed in one of the previously described embodiments. The function display is preferably a component of an operating element fastened on the steering wheel. The legs of the operating element are fixed, for example, on the steering wheel rim in a rotationally fixed manner. The display surface of the function display is preferably arranged between the steering wheel ring and the steering wheel hub or the bumper of the steering wheel covering the steering wheel hub.

Description of drawings

The invention and the technical environment are explained in more detail below with the aid of the drawings. It should be noted that the figures show particularly preferred implementation variants of the invention, but the invention is not restricted to these implementation variants. The accompanying drawings schematically show:

FIG. 1 is a schematic cross-sectional view of a first embodiment of the invention of a functional display 1;

FIG. 2 is a schematic sectional view of an embodiment of the invention of an operating element 10 with a functional display;

FIG. 3 is a top view of the steering wheel according to the invention with operating elements 10 comprising a functional display 1;

FIG. 4 is a horizontal cross-sectional view of the assembly of the invention formed by two functional displays 1, 1';

FIG. 5 is a horizontal sectional view of another inventive assembly formed by two functional displays 1 , 1 ′.

detailed description

FIG. 1 schematically shows a first embodiment according to the invention of a functional display 1 . The functional display 1 comprises an outer transparent or translucent, but at the same time not mandatory and only optionally provided cover layer 23 , which delimits the surface facing the viewer B in the intended arrangement of the functional display 1 . The cover layer is made, for example, of a plastic, preferably a thermoplastic, such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile-butane alkene-styrene (ABS) or polymethylmethacrylate (PMMA), or a layer formed of a glass material. The covering layer 23 can also be part of a layer construction formed from a plurality of layers.

According to the invention, the functional display 1 also compulsorily comprises a light guide stack consisting of at least two transparent or translucent planar light guides arranged one above the other, each formed of a thermoplastic layer or a thermoplastic foil. Conductors 13, 14 are formed. The light conductors 13, 14 are separated by a layer 24 arranged between the light conductors 13, 14, said layer (here an air gap) consisting of a material having a lower refractive index than the adjacent light conductors 13, 14 ( In this case, air) forms. This air layer 24 is likewise arranged between the cover layer 23 and the nearest adjacent light conductor 13 . The light guides 13, 14 each form at least a main face H facing the observer B and a main face H' facing away from the observer, while the upper light guide 13, which is closer to the observer B, has a main face facing away from the observer and facing in the stacking direction. The main surface H′ of the next adjacent optical waveguide 14 .

The light conductors 13 , 14 are each assigned a light source 12 , namely a light-emitting diode in SMD construction, which is arranged such that the light generated by it is incident on the assigned light via an end face S lateral to the stacking direction. Conductors 13, 14. In order to prevent undesired light scattering or light radiation from entering the adjacent light conductors 13, 14, respectively, baffles 17 are provided. At the end faces opposite each other, an anti-reflection coating 33 is applied to the end faces of the light guides 13, 14 in order to minimize back reflections in the respective light guide 13, 14, while the light guides 13, 14 are form-fitted. fixed in the frame 25. In at least one main surface of the light guide 13 , here in the main surface H′ facing away from the observer, a plurality of individual microstructures 16 are introduced by embossing or shaping, which microstructures are responsible for the light incident into the light guide 13 . The light L emerges from the corresponding light guide 13 by light refraction and/or light scattering in the direction of the observer B and defines a microstructured symbol area comprising microstructures 16 . This symbol area alone or in optical cooperation with other symbol areas reproduces the shape of the symbol, which is visible to the observer B in luminescence when the associated light source 12 is correspondingly activated.

The microstructures 16 are formed in the same shape as each other and have a maximum diameter in the range of 1 to 25 μm. The light guide 14 facing away from the observer B likewise has microstructures 26 in its main face H facing the observer B, which are likewise unitary and formed identically to one another. These microstructures are also introduced into the relevant main surface of the light guide 14 , here the main surface H facing the viewer B, by embossing or shaping. These couple the light L′ incident into the light guide 14 in the direction of the mirror 27 which is arranged on the side of the light guide stack formed by the light guides 13 , 14 facing away from the observer B, here The mirror is in the form of a partially transmissive metallic vapor-phase coating on the transparent plastic layer 28 , which is arranged at a distance from the light guide 14 at a distance from the light guide 14 via an air gap 24 , alternatively it is also conceivable to adjoin Arrangement of the photoconductor 14 .

The light L' originally incident on the light guide 14 is reflected in the direction of the observer B only by the reflection of the mirror 27. Thus, depending on the activation of the light source 12 at the observer B, a depth effect or even a stereoscopic impression of the displayed symbol can be achieved through different display planes. In one refinement, this is achieved, for example, by simultaneously displaying the symbol field display of the lower light conductor 14 of the light conductor stack with a mirror and the same symbol field display of the upper light conductor bypassing the mirror, wherein the symbol The parallax shifting of the regions creates the illusion for a binocular observer of the three-dimensional nature of the displayed symbols.

In another refinement, for example, switching between the symbol display of the lower light conductor 14 of the light conductor stack using the mirror and the symbol display of the upper light conductor 13 bypassing the mirror, for example in chronological order, it is also possible for the observer to Attention is drawn to the function display 1, which is achieved by changing the display plane of the function display 1. By selectively activating the light source, it is relatively simple to visualize different light states or switch functions. Functional display 1 can be realized simply and with low cost and has brought a large design space to the designer, and this also relates to the arrangement mode of functional display 1. Functional displays exhibit virtually no aging effects from light radiation and are relatively energy-efficient. A microstructured symbol field reproduces a symbol in engraved form as an image, as its reverse illustration or as its outline, for example alone or together with other symbol fields. The aforementioned depth effect can be set, for example, by the distance between the light guides 13 , 14 , for example the air gap thickness. Said distance is for example in the range of 1 to 3 mm.

All light guides 13 , 14 are transparent outside the microstructured regions. Since the mirror 17 is also provided with partial light transmission, a large part of the display surface 8 is optically transparent, so that, for example, a perspective through the functional display is ensured in order to give the observer B to follow other displays or paths through the functional display possibility of going. Thus, for example, the functional display 1 can be placed on the steering wheel, for example in the area between the steering wheel hub and the steering wheel rim, without affecting the view of the instrument panel. When viewing the display surface 8 perpendicularly to the microstructured areas of all light guides 13, 14, the projected microstructured symbol areas of the individual light guides 13, 14 do not overlap in order not to impair the display quality of the symbols.

FIG. 2 shows an embodiment of the operating element 1 according to the invention. This operating element has a leg 3 for fixing the operating element 1 on a vehicle component such as a dashboard, a lining of the passenger compartment or in particular a steering wheel rim 11 of a steering wheel of a motor vehicle. The operating element 10 according to the invention also has an operating part 2 defining an operating surface 9, said operating part being formed as at least one self-supporting lever arm. The self-supporting lever arms are supported on one side by means of solid joints 4 at the legs 3 in order to be able to pivot the operating part 2 relative to the legs 3 against a restoring force under an actuating force acting perpendicularly to the operating surface 9 The imaginary pivot axis A pivots. The restoring force is produced, for example, by deformation of the solid articulation 4 .

According to the invention, means 6 are also provided in order to detect the degree of pivoting between the operating part 2 and the leg 3 . The solid hinge 4 is formed only by the one-piece connection between the leg 3 and the operating part 2 . The operating element 1 according to the invention is particularly suitable for a design in which the maximum pivoting from the unactuated rest position shown in FIG. 2 about the imaginary pivot axis A to the maximum possible actuated pivot position The degree is less than 10°, preferably less than 5°.

According to the invention there is also provided an actuator 5 which can be acted upon with an electrical control signal by control electronics not shown in order to generate an active tactile feedback (also called tactile output), wherein the actuator 5 is preferably only fixed at operating part 2. The actuator 5 is preferably an inertia-based, motor-based actuator, such as an electric motor with a mass mounted eccentrically with respect to its center of gravity fixed on its rotating drive shaft or a magnet-coil actuator or a piezoelectric actuator Or a linear broadband actuator such as a plunger coil actuator (English name: Voice-Coil-Actuator, voice coil actuator) or a linear resonant actuator. The actuator 5 is preferably fastened to the operating part 2 by a force-fit or material-fit connection, for example by screwing or gluing. Due to the fastening at the operating part 2 only, the input of structure-borne noise into the steering wheel rim 11 and thus into the vehicle components is prevented, or at least minimized.

The means 6 for detecting the degree of pivoting is formed to capacitively, optically and/or inductively detect the degree of pivoting between the leg 3 and the operating part 2 . Due to the play-free bearing of the operating part 2 by means of the solid hinge 4 in cooperation with the means 6 for preferably contactless detection of the degree of pivoting, a low-to-hysteresis-free detection of the actuation force, for example set An output for triggering a switching function or a control function or at least an optically, acoustically or tactilely perceivable output.

The operating surface 9 is provided by a transparent cover layer 23 of the functional display 1 which covers the display surface 8 of the functional display 1 . The functional display 1 is formed partially transparent in order to ensure that an observer or operator has an unhindered view through the functional display 1 of an operating area located below it, such as the instruments of a dashboard. According to the invention, the functional display 1 also comprises a light conductor stack formed from three transparent or translucent planar light conductors 13 , 14 , 15 arranged one above the other, each formed from a thermoplastic foil. . The light conductors 13, 14, 15 are respectively separated by an air layer 24 arranged between the light conductors 13, 14, 15, said air layer thus forming a gap between two adjacent ones of the light conductors 13, 14, 15 respectively. air gap. This air layer 24 is likewise arranged between the cover layer 23 and the nearest adjacent light conductor 13 .

The light guides 13 , 14 , 15 each form at least a main face H facing the observer B, while the upper two light guides 13 , 14 which are closer to the viewer B each have a lower face facing away from the viewer in the stacking direction. The main surface H′ of an adjacent optical waveguide 14 or 15 . The light conductors 13 , 14 , 15 are each assigned a light source 12 , namely a light-emitting diode in SMD construction, which is arranged such that the light generated by it is incident on the assigned light source via an end face lateral to the stacking direction. In the photoconductor 13,14,15. In order to prevent here, respectively, undesired light scattering or light radiation entering the connected light conductors 13 , 14 , 15 , baffles 17 are provided. At the end faces 25 opposite one another, an antireflection coating 25 is applied to the end faces of the light guides 13 , 14 , 15 in order to minimize back reflections in the respective light guide 13 , 14 , 15 . In at least one of the main faces of the light guide (here light guide 13 , 14 ) is introduced by embossing a microstructured symbol area formed by a plurality of microstructures 16 , which makes light from the corresponding light The conductors 13 , 14 emerge in the direction of the observer B . The microstructures 16 are formed to have the same shape and have a diameter in the range of 1 to 25 µm, respectively. The light guide 14 as well as the light guide 15 also have a plurality of microstructures 26 .

The lower light guide 15 and the middle light guide 14 facing away from the observer B likewise have microstructures 26 in their main face H facing the observer B, which are likewise unitary and formed identically to each other. These microstructures are also introduced by embossing or forming into the relevant main surface of the respective light guide 14, 15, here the main surface H facing the viewer B. This main face couples the light incident into the respective light guide 14 , 15 in the direction of the mirror 27 which is arranged on the side of the light guide stack formed by the light guides 13 , 14 , 15 facing away from the observer B , here in the form of a reverse partially transmissive metal vapor phase coating on the transparent plastic layer 28 , which adjoins the lower light guide 15 here, alternatively it is also conceivable to be spaced from the light guide 15 arrangement. The light originally incident into the light guide 14 is reflected in the direction of the observer B only by the reflection by the mirror 27. Thus, at the observer B, depending on the activation of the light source 12, a depth effect or even a stereoscopic impression of the displayed symbol can be achieved through different display planes. In one refinement, this is achieved, for example, by simultaneously displaying the symbol field display of the lower light conductor 14 of the light conductor stack with a mirror and the same symbol field display of the upper light conductor bypassing the mirror, wherein the symbol The parallax shift of the zones convinces the binocular observer of the three-dimensional nature of the displayed symbols. In another refinement, for example, switching between the symbol display of the light conductors 14, 15 of the light conductor stack with the mirror and the symbol display of the light conductors 13, 14 bypassing the mirror, for example in chronological order, it is also possible to The observer's attention is drawn to the functional display 1 by changing the display plane of the functional display 1 . By selectively activating the light source, it is relatively simple to visualize the different switching states or switching functions. Functional display 1 can be realized simply and with low cost and has brought a lot of design space to the designer, and this also relates to the placement mode of functional display 1. Functional displays exhibit virtually no aging phenomena affected by light radiation and are relatively energy-efficient. A microstructured symbol field reproduces a symbol in embossed form as an image, as its reverse illustration or as its outline, for example alone or together with other symbol fields. The aforementioned depth effect can be set, for example, by the distance between the light guides 13, 14, 15, for example the air gap thickness. The distance is, for example, in the range of 1 to 3 mm.

All light guides 13, 14, 15 are transparent outside the microstructured area, so that a large part of the display surface 8 remains transparent and for example ensures a see-through through the functional display 1 in order to give the viewer B through Possibility for functional monitors to follow other monitors or the course of the road. Thus, for example, the functional display 1 can be placed at the steering wheel, for example in the area between the steering wheel hub and the steering wheel rim, without affecting the viewing of the instrument panel. When viewing the display surface 8 perpendicularly, the microstructured symbol areas of the light guides 13, 14, 15 overlap at least partially, so that by using light sources 12 with light radiation of different colors to produce multicolored symbols, which can be obtained by Simultaneously, several light guides 13 , 14 , 15 are fully illuminated to become visible. In order to avoid undesired light propagation in the corresponding light guide 13 , 14 , 15 , in particular when external light acts, each light guide 13 , 14 , 15 has at least one of its end faces, preferably at the side not facing the light source 12 At the end faces there is an anti-reflection coating 33, which is also commonly referred to as anti-reflection coating or compensation layer. The task of the anti-reflection coating is to reduce the amount of light reflected into the light guide at the coated end face relative to an uncoated end face, e.g. by absorbing light in the coating 33. This coating 33 can be applied approximately circumferentially. This anti-reflection coating 33 has, for example, an optical refractive index which is between air and the material of the light guide 13,14,15 in value. The ends of the light guides 13, 14, 15 facing away from the light source 12 are fixed in the frame 25 in a material fit manner respectively.

As shown in FIG. 3 , the invention also relates to a steering wheel 20 . The steering wheel 20 has a damper 22 covering the steering wheel hub, at least one steering wheel spoke 21 and a steering wheel rim 11 carried by said steering wheel spoke 21 . The steering wheel 20 according to the invention also has a function display 1 which is an integral part of the operating element 10 fastened to the steering wheel 20 and which is integrated into the operating part 2 , which is supported in a pivotally movable manner on the operating at the legs of element 10. Here, the legs of the operating element 10 are secured against rotation at the steering wheel rim 11. The substantially transparent display surface 8 of the functional display 1 is arranged between the steering wheel rim 11 and the steering wheel hub or bumper 22 of the steering wheel 20 covering the steering wheel hub. When selectively activating the light sources belonging to the functional display 1 , depending on this selection, different symbols 18 in the area of the display surface 8 become visible to the observer (that is to say the driver), whereas the functional display 1 in the rest of the Transparency in the area in which the instrument panel or its instruments located behind the steering wheel 20 are visible to the driver.

FIG. 4 shows a sectional view through an assembly according to the invention formed by a plurality of functional displays 1 , 1 ′, for example each having a sectional configuration as shown in FIG. 1 , 4 or 5 and viewed from the viewer. Viewed next to each other, the display surfaces 8 , 8 ′ are thus formed adjacent to each other. What is unique about this arrangement is that at least one light guide 13 of one functional display 1 is integrally formed with a light guide 13' of another functional display 1' in order to form a common light guide. The other light guides which are not shown here and which are located below are formed correspondingly with the same dimensions. However, the invention also includes embodiments in which the light conductors of each functional display 1, 1' are formed to differ in their outer dimensions. In order to minimize the mutual incidence of light from one functional display 1 into the other functional display 1' and vice versa, conical interruptions 29 are formed in the common light guide 13, 13', said interruptions being made with a ratio The material of the common optical waveguide 13 , 13 ′ is filled with a material having a lower refractive index. Here, some of the end faces of the light conductors 13, 13' are provided with an anti-reflection coating 33.

FIG. 5 shows a cross-sectional view through another assembly of the invention formed by a plurality of functional displays 1, 1', for example each having a cross-sectional configuration as shown in FIG. 1, 4 or 5 and viewed from the observer Viewed from a viewing angle, they are arranged next to each other, so that display surfaces 8 , 8 ′ arranged next to each other are thus formed. This arrangement is also unique in that at least one light guide 13 of one functional display 1 is integrally formed with a light guide 13' of another functional display 1' in order to form a common light guide. The other light guides, which are not shown here and are located below, are formed correspondingly with the same dimensions. However, the invention also includes embodiments in which the light guides of each functional display 1, 1' are formed to differ in their outer dimensions. In order to minimize the mutual light incidence from one functional display 1 into the other functional display 1' and vice versa, it can be seen from FIG. The section is filled with a material having a lower refractive index than the material of the shared light conductor 13 , 13 ′. In the embodiment shown in Fig. 5 this tapered interruption is omitted. In the embodiment shown therein, the respective light conductors 13, 13' respectively form curved interfaces 30, 32 in the respective light course from the light source 12, 12' to the associated symbol 18, 18' in order to form an optically efficient , preferably focusing lens elements. For example, in the light guide 13 , in the outer end face of the light guide 13 there is provided an entrance face 30 concave relative to the light guide, whereas the light guide 13 ′ has a plurality of interruptions 31 with a ratio common to the light guide 13 . The material of the light guide 13 , 13 ′ is filled with a material having a lower refractive index. The lens element formed by the interruption 31 also acts in a focusing manner on the light course from the light source 12' to the associated symbol 18'. Here, some of the end faces of the light guides 13 , 13 ′ are provided with an antireflection coating 33 .

Claims (17)

1. A function display (1) for selectively displaying symbols (18) representing switch functions and/or switch states, especially for a motor vehicle, said function display having: A light-conductor stack which forms a display surface (8) facing the viewer (B) when the functional display (1) is installed as intended; wherein the light-conductor stack is composed of Formed by at least two transparent or translucent planar light guides (13, 14, 15) arranged one above the other in direction, said light guides being arranged to be separated by a transparent or translucent layer, preferably via an air gap (24) On the other hand, the layers are formed of an optically thinner material than the adjacent light guides, so that the light guides (13, 14, 15) respectively have a main face (H) facing the viewer (B) and facing away from the the main face (H') of the observer (B) and in at least one light guide (13, 14, 15) facing away from the main face (H') of the observer (B) The next adjacent photoconductor (13, 14, 15) in the direction opposite to the stack direction; at least one light source (12, 12') for each light guide (13, 14, 15), said light source being arranged to direct light (L, L') via the end face of the associated light guide (13, 14, 15) (S) is incident on the corresponding photoconductor (13, 14, 15); Wherein each light guide (13, 14, 15) is also provided with at least one microstructured symbol area arranged in or on said light guide (13, 14, 15), said sign area comprising a plurality of refraction The optical and/or light-scattering microstructures (16, 26) are also formed in such a way that when the light source (12, 12') is activated by means of the light incident into the light guide (13, 14, 15) is luminescently visible to said viewer (B) so as to display to said viewer (B) a symbol (18) composed of one or more microstructured symbol regions; A mirror (27) arranged on the side of the light conductor stack facing away from the observer (B) so as to direct incident light into at least one of the light guides (13, 14, 15) and The light (L') emerging from the light guide (13, 14, 15) is then reflected in the direction of the observer (B) by means of the associated microstructures (26). 2. The functional display (1) according to claim 1, wherein said microstructures (16) of at least one microstructured photoconductor (13, 14, 15) are formed such that the light incident on the corresponding photoconductor (13) , 14, 15) the light (L) exits in the direction of the observer (B). 3. The functional display (1) according to any one of the preceding claims, wherein the microstructured symbol areas each comprise a plurality of, preferably single, microstructures (16, 26) formed in the same shape as one another . 4. The functional display (1) according to any one of the preceding claims, wherein the microstructures (16 , 26) with an average number density in the range of 1000 to 4000 pieces per mm ² . 5. The functional display (1) as claimed in any one of the preceding claims, wherein the microstructures (16, 26) of all microstructured symbol areas each have a maximum diameter in the range of 1 to 25 μm. 6. Functional display (1) according to any one of the preceding claims, wherein said microstructures (16, 26) pass through the main face (H, H' of each light conductor (13, 14, 15) ) One of the embossed formation. 7. The functional display (1) as claimed in any one of the preceding claims, wherein the area proportion of all microstructured symbol areas accounts for less than half of the display surface (8). 8. The functional display (1) according to any one of the preceding claims, wherein at least two light conductors (13, 14, 15) of the light conductor stack when viewing the display surface (8) vertically The microstructured symbol areas of are arranged non-overlapping, preferably spaced apart from each other for the observer (B). 9. The functional display (1) according to any one of the preceding claims, wherein at least two photoconductors (13, 14, 15) of the photoconductor stack when viewing the display surface (8) vertically The microstructured symbol areas of are arranged adjacent to one another, preferably overlapping, more preferably completely overlapping for the observer (B). 10. Functional display (1) according to any one of the preceding claims, wherein at least two light sources (12) differ in light colour. 11. Functional display (1) according to any one of the preceding claims, wherein the light conductors (13, 14, 15) each have a foil or are formed by a foil. 12. The functional display (1) according to any one of the preceding claims, wherein a lens and/or a baffle is respectively arranged between the light guide (13, 14, 15) and the light source (12) (17) and/or light channel. 13. The functional display (1) according to any one of the preceding claims, wherein at least one light conductor (13) of the light conductors of the light conductor stack is in the distance from the light source (12) to the associated micro The respective beam paths of the structured symbol areas each have at least one curved interface (32, 30) in order to form at least one focusing lens element. 14. An assembly formed of a plurality of functional displays (1, 1'), respectively formed according to any one of the preceding claims and forming a plurality of each other from the viewpoint of the observer (B) The display surfaces (8, 8') are arranged next to each other and in which at least the cover layer (23) and/or at least one light guide (13, 13') are integrally formed. 15. Operating element (10) having a function display (1) according to any one of the preceding claims. 16. The operating element (10) according to the preceding claim, wherein the display surface (8) is formed as an operating part (2) of the operating element (10) intended for contact or actuation The translucent and/or transparent part of the control surface (9) or the display surface is arranged below the translucent and/or transparent cover layer forming the control surface (9). 17. A steering wheel (20) for a motor vehicle, said steering wheel having a function display (1) according to one of the preceding claims 1 to 13.

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