Function display for selectively displaying at least one symbol representing a switching function and / or a plurality of switching states and associated manufacturing method

Abstract

The invention relates to a functional display having at least one planar light conductor formed from at least one transparent or translucent first material, having two mutually opposed main faces and at least one end face, one of the main faces facing the observer as a display face and the other main face facing away from the observer, at least one light source being arranged to introduce light from the light source into the light conductor via the end face of the light conductor, at least one main face of the light conductor being surface-structured by means of a plurality of microstructures introduced into the respective main face which have a refractive and / or scattering effect on the light, a coating being applied only locally on the region of the surface-structuring of the main face, the coating being formed from a transparent or translucent second material, the light introduced into the light conductor being caused to exit in the direction of the observer by refraction of the light and / or scattering of the light in the uncoated symbol region in the event of activation of the light source, the symbols produced and illuminated by the uncoated surface-structured symbol region being visible to the observer.

Description

Technical Field

[0001] The present invention relates to a functional display for selectively displaying at least one symbol representing a switch function and / or multiple switch states. Background Technology

[0002] These functional displays are necessary, for example, in multi-functional operating elements, to visualize the switching functions and / or switching states associated with the operating element. Electronic pixel matrix displays are typically used for this purpose. However, they are relatively expensive, and their rectangular shape, in most cases, limits their configuration and placement. Furthermore, electronic pixel matrix displays often suffer from "burn-in" when displaying static content; that is, the displayed content remains undesirably visible even when the display is off due to visually perceptible damage to the display's imaging layer. Additionally, such electronic pixel matrix displays consume relatively high amounts of power. Moreover, in some applications, conventional electronic pixel matrix displays are prohibited due to the risk of injury, such as in the event of a head impact. As an alternative to pixel matrix displays, light incident on the end face of a light conductor is selectively emitted by means of a surface structure at the main surface used as the display surface, where only a localized area with the surface structure is provided, and symbols, etc., are reproduced. The disadvantage here is that, for quality reasons, accurately placing the surface-structured area on the main surface used as the display surface and forming a clear boundary for this area poses significant difficulties in the manufacturing process, especially when the symbols to be reproduced through the surface-structured area are relatively small and occupy less than 2 cm. 2 When the total area is... Summary of the Invention

[0003] Against this backdrop, the object of the present invention is to provide a functional display that increases design flexibility, can be manufactured cost-effectively, is energy-efficient and reliable, and / or, particularly, reduces the risk of injury in the event of a head impact. This object is achieved by the functional display as described in claim 1. Correspondingly advantageous operating elements, a steering wheel incorporating the functional display, and related manufacturing methods are the subject of the co-main claims. Advantageous design embodiments are the subject of the dependent claims. It should be noted that the features individually detailed in the claims can be combined with each other in any technically meaningful manner and demonstrate other embodiments of the invention. The description, in particular, is supplemented with and describes the invention in detail in conjunction with the drawings.

[0004] This invention relates to a functional display, particularly for motor vehicles, for selectively displaying at least one symbol representing a switching function and / or multiple switching states. Selective display is understood not only as the selective display of different symbols from a plurality of pre-given symbols, which in the solution of this invention is achieved by selectively selecting one or more light sources from a plurality of light sources and energizing them, but also as switching the light sources to selectively reveal the symbols to the observer visually through activated backlighting or to make the symbols nearly disappear from the observer's view by turning off the backlighting.

[0005] The functional display of the present invention includes at least one planar light conductor formed of at least one transparent or translucent first material, the light conductor having two opposing main surfaces and at least one end surface, wherein, in the intended arrangement of the functional display, one main surface faces an observer (e.g., a vehicle driver) and serves as the display surface, and the other main surface faces away from the observer. The light conductor, for example, has two opposing, preferably parallel, main surfaces, which are connected via an end surface, for example, at the narrow side and the long side of the light conductor, the end surface forming a common edge together with the main surfaces of the light conductor. The end surface, for example, is orthogonal to at least one or both main surfaces of the light conductor.

[0006] At least one material is, for example, a plastic, preferably a thermoplastic, such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile-butadiene-styrene (ABS), or polymethyl methacrylate (PMMA), or a glass material. The main surface is understood, for example, as those surfaces of the light conductor having the largest area. Apart from the surface structuring described below, the main surface is preferably designed to be substantially flat. The light conductor may be provided with a transparent or translucent coating, such as a paint layer.

[0007] According to the invention, a functional display has at least one light source arranged to incident light from the light source into the light conductor via an end facet of the light conductor. To improve light incidence and / or to adapt the light radiation characteristics of the light source to the end facet designated for allowing light into the light conductor, a lens and / or baffle are preferably arranged between the light conductor and the light source. The baffle is, for example, also formed to suppress light leakage into other light conductors besides the designated light conductor.

[0008] Here, one of the main surfaces of the photoconductor is surface-structured by means of multiple microstructures introduced into the respective main surface to refract and / or scatter light. A microstructure is understood, for example, as a single protrusion or a single depression on the main surface. Here, the maximum size of each microstructure is in the range of 1 to 50 µm, preferably in the range of 1 to 25 µm, such that each individual microstructure is indistinguishable at the expected viewing distance and without visual aids for the human eye. The microstructures are preferably arranged in a uniformly spaced distribution over the entire surface-structured area of ​​the main surface. The microstructures are, for example, shaped like pyramids or prisms. The microstructures are preferably formed to be identical in shape, and preferably not only uniformly shaped but also uniformly oriented. For example, a uniform orientation can only be achieved on a flat main surface if each microstructure can be mapped onto an adjacent microstructure by an imaginary, translationally-only offset. The microstructure is more preferably formed to generate a collimated beam of light exiting the light conductor, formed by light from a light source and which has previously entered the light conductor via the end face.

[0009] According to the invention, a coating is also provided that is applied only locally to the surface-structured region of the main surface. The coating is formed of a transparent or translucent second material, such that the surface-structured region includes at least one coated surface-structured region in addition to at least one continuous uncoated surface-structured symbol region on the main surface. The at least one coated surface-structured region preferably surrounds the uncoated surface-structured symbol region.

[0010] When the light source is activated, light incident on the photoconductor is refracted and / or scattered in the uncoated, surface-structured symbol regions, causing light to exit towards the observer, making the symbols generated and illuminated by the uncoated, surface-structured symbol regions visible to the observer. Surface structuring, through light refraction and / or scattering, promotes, for example, enhanced light exit towards the observer compared to a flat design of the main surface involved. For example, the microstructures enable light to strike interfaces pre-defined by the microstructures at angles that do not satisfy total internal reflection, causing light to exit the photoconductor in the regions of the microstructures. The total area of ​​all uncoated, surface-structured symbol regions is preferably less than 2 cm². 2 .

[0011] Because the coating predefines the uncoated surface-structured symbol area, especially its boundaries—that is, the interface design, position, and size between the uncoated surface-structured symbol area and the coated surface-structured area—these factors depend only on the choice of coating method and no longer on the type and execution method of surface structuring. This not only simplifies the manufacturing process but also improves the design freedom when displaying the symbol by using a surface coating as a means of implementing the predetermined design. Furthermore, this creates the possibility of pre-producing photoconductors for multiple symbols without being forced to associate them with a specific symbol. Functional displays can be implemented simply and cost-effectively, providing designers with considerable design flexibility, including the placement of the functional displays. Functional displays exhibit minimal aging effects from light radiation and are relatively energy-efficient. The uncoated surface-structured symbol area can, for example, display the symbol's front as an image, as its opposite illustration, or as a reproduction of its outline.

[0012] Surface structuring can be introduced into the photoconductor via laser ablation. The surface-structured regions are preferably created by imprinting and / or molding. The microstructure is introduced into the relevant main surface, for example by means of a mold, through vacuum forming or injection molding, wherein the forming surface of the mold transfers the structure to be transferred onto the photoconductor.

[0013] The coating is preferably formed to fill microstructures disposed in the coated surface-structured regions. The coating preferably forms a continuous surface surrounding the uncoated surface-structured symbolic regions of the main surface.

[0014] The surface-structured region preferably has 3D microstructures formed in the same shape, the average number density of which on the surface-structured region is in the range of 500 to 7000 per square millimeter, preferably in the range of 1000 to 4000 per square millimeter. It has been shown that such a number density generates a brightness distribution sufficient for visual discernibility when the light source is on, while being visually inconspicuous when the light source is off, making the surface-structured region indistinguishable at the expected viewing distance for the naked eye, and in particular not obstructing the line of sight that may be seen through the functional display in certain situations.

[0015] The second material is preferably a transparent curing varnish, a transparent curing adhesive, or a transparent curing resin. The adhesive is preferably a thermosetting adhesive, which is introduced into a molding die to produce the photoconductor using the first material. The temperature of the adhesive is set, for example, above 280°C by selecting the temperature of the mold, thereby achieving solidification or curing of the adhesive. Solidification is understood, for example, as the chemical and / or physical curing of the adhesive, such as increasing the degree of crosslinking of the adhesive.

[0016] The area ratio of all uncoated surface-structured symbol regions to the entire surface-structured region of the relevant main surface of the photoconductor is preferably less than 0.5, and more preferably less than 0.3.

[0017] To avoid internal reflection, the refractive indices of the first and second materials should differ from each other by no more than 0.2, preferably 0.1.

[0018] The optical conductors preferably each have at least one foil, such as a multi-layer foil structure. For example, the optical conductors are produced by back-injection molding of transparent foils (such as PC foils or PE foils) with a first material, especially a thermoplastic.

[0019] The functional display is preferably transparent to the observer in an area outside the uncoated surface structured symbol area of ​​the display surface, so as to reveal the vehicle's road direction or other displays to the viewer in the area behind the functional display.

[0020] To prevent unwanted light from propagating in the optical conductor, especially when exposed to external light, according to a preferred embodiment, the optical conductor has an anti-reflective coating at at least one end face, preferably the end face opposite to the end face facing the light source. This anti-reflective coating is also commonly referred to as an anti-reflective coating or compensation layer. The task of the anti-reflective coating is, for example, to reduce the amount of light reflected into the optical conductor at the coated end face, relative to the uncoated end face, by absorbing light within the coating. The anti-reflective coating can be applied circumferentially, for example, from the perspective of the light incident area provided for the light from the light source. This anti-reflective coating, for example, has an optical refractive index numerically between that of air and the material of the optical conductor.

[0021] According to a preferred design, a plurality of light conductors are provided, the light conductors being arranged such that at least one of the main surfaces of the light conductors faces the main surface of an adjacent light conductor, and the main surfaces are spaced apart by an air gap or a gap formed by a material that is optically thinner than the first and second materials, wherein uncoated symbol regions are arranged relative to each other in a laterally offset manner with respect to the stacking direction of the light conductors, preferably without overlapping. By selectively activating the light source, different on / off states or switching functions can be visualized relatively easily.

[0022] The color of the light incident on the light conductor is preferably different in different light conductors.

[0023] The present invention also relates to an operating element having a functional display formed in one of the previously described embodiments. The operating element, for example, has a leg for securing the operating element to a vehicle component such as an instrument panel, a passenger compartment liner, or, in particular, a steering wheel of a motor vehicle. Here, the main surface serving as the display surface forms the operating surface of the operating element, which is determined to be an operating member for contacting or actuating the operating component. The operating member is, for example, formed as at least one self-supporting lever arm. The self-supporting lever arm is supported on one side by means of a solid hinge so that, under the action of an operating force perpendicular to the operating surface, the operating member can pivot relative to the leg about an imaginary pivot axis against a restoring force. For example, a device is also provided to detect the degree of pivoting between the operating member and the leg. Generally, the following region of the component is referred to as the solid hinge: this region allows pivoting between two rigid body regions by bending. The solid hinge provides gapless and thus noiseless support for the operating member at the leg. The legs and operating components are formed, for example, of thermoplastics such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile-butadiene-styrene (ABS), or polymethyl methacrylate (PMMA). The operating element of the present invention is particularly suitable for designs in which the maximum pivoting degree from the unacted rest position about an imaginary pivot axis to the actuated maximum pivot position is less than 10°, preferably less than 5°.

[0024] The present invention also relates to a steering wheel, which, for example, has a steering wheel hub, at least one steering wheel spoke, and a steering wheel rim supported by the steering wheel spoke. The steering wheel according to the invention also has a function display formed in one of the previously described embodiments. The function display is preferably a component of an operating element fastened to the steering wheel. The legs of the operating element are, for example, fixed to the steering wheel rim in an anti-rotational manner. The display surface of the function display is preferably arranged between the steering wheel rim and the steering wheel hub or a buffer covering the steering wheel hub.

[0025] The present invention also relates to a method for manufacturing a functional display, particularly for motor vehicles, for selectively displaying at least one symbol representing a switching function and / or multiple switching states, the method comprising the following steps. In a production step, at least one planar optical conductor is produced from a transparent or translucent first material, wherein the optical conductor has two opposing main surfaces and at least one end surface, wherein, in accordance with the intended arrangement of the functional display, one main surface forms a display surface facing the observer and the other main surface is arranged facing away from the observer.

[0026] Surface structuring is performed simultaneously or subsequently in time, wherein at least one of the main surfaces of the photoconductor is surface-structured by means of a plurality of microstructures introduced into the main surface to perform light refraction and / or light scattering. Microstructures are understood, for example, as a single protrusion or depression on the main surface, having a maximum size in the range of 1 to 50 µm, preferably in the range of 1 to 25 µm.

[0027] The microstructures are preferably arranged in a uniformly spaced distribution on the structured area of ​​the main surface. The microstructures are, for example, pyramidal or prism-shaped. The microstructures are preferably formed to be identical in shape, and preferably not only uniformly shaped but also uniformly oriented. For example, uniform orientation can only be achieved on a flat main surface if each microstructure can be mapped onto an adjacent microstructure by an imaginary, translational offset. More preferably, the microstructures are formed to generate a collimated beam of light exiting the light conductor, the light originating from a light source and having previously entered the light conductor through the end face.

[0028] Subsequently, a transparent or semi-transparent second material is used to partially coat only the surface-structured area of ​​the main surface, leaving at least one continuous uncoated surface-structured symbol area on the main surface involved and generating at least one coated surface-structured area on the associated main surface.

[0029] Subsequently, at least one light source is secured, the light source being arranged to incident light into the light conductor via an end face of the light conductor, such that when the light source is activated, light incident into the light conductor is caused to exit toward the observer by light refraction and / or light scattering in the uncoated surface-structured symbol region, and such that the symbols generated and illuminated through the uncoated surface-structured symbol region are visible to the observer.

[0030] Because the coating thus predefines the uncoated surface-structured symbol area, especially its boundaries—that is, the interface design, position, and size between the uncoated surface-structured symbol area and the coated surface-structured area—they depend only on the choice of coating method and no longer on the type of surface structuring method. This not only simplifies the manufacturing process but also improves the design freedom when displaying the symbol by using a surface coating as a means of implementing the predetermined design of the symbol. Furthermore, this creates the possibility of pre-producing uncoated photoconductors for multiple symbols without being forced to associate them with a specific symbol. Functional displays can be implemented simply and cost-effectively, providing designers with considerable design flexibility, including the placement of the functional displays. Functional displays exhibit minimal aging effects from light radiation and are relatively energy-efficient. The uncoated surface-structured symbol area can, for example, display the symbol's front as an image, as its opposite illustration, or as a reproduction of its outline.

[0031] Surface structuring can be introduced into the photoconductor via laser ablation. The surface-structured regions are preferably created by imprinting and / or molding. The microstructure is introduced into the relevant main surface, for example by means of a mold, through vacuum forming or injection molding, wherein the forming surface of the mold transfers the structure to be transferred onto the photoconductor.

[0032] The coating is preferably formed to fill microstructures disposed in the coated surface-structured regions. The coating preferably forms a continuous surface surrounding the uncoated surface-structured symbolic regions of the main surface.

[0033] The surface-structured region preferably has 3D microstructures formed in the same shape, the average number density of which on the surface-structured region is in the range of 500 to 7000 per square millimeter, preferably in the range of 1000 to 4000 per square millimeter. It has been shown that such a number density generates a brightness distribution sufficient for visual discernibility when the light source is on, while being visually inconspicuous when the light source is off, making the surface-structured region indistinguishable at the expected viewing distance for the naked eye, and in particular not obstructing the line of sight that may be seen through the functional display in certain situations.

[0034] The second material is preferably a transparent curing varnish, a transparent curing adhesive, or a transparent curing resin. The adhesive is preferably a thermosetting adhesive, which is introduced into a molding die to produce the photoconductor using the first material. The temperature of the adhesive is set, for example, above 280°C by selecting the temperature of the mold, thereby achieving solidification or curing of the adhesive. Solidification is understood, for example, as the chemical and / or physical curing of the adhesive, such as increasing the degree of crosslinking of the adhesive.

[0035] The area ratio of all uncoated surface-structured symbol regions in the entire surface-structured region of the relevant principal surface of the relevant photoconductor is preferably less than 0.5, and more preferably less than 0.3.

[0036] To avoid internal reflection, the refractive indices of the first and second materials should differ from each other by no more than 0.2, preferably 0.1.

[0037] The optical conductors preferably each have at least one foil, such as a multi-layer foil structure. For example, the optical conductors are produced by back-injection molding of transparent foils (such as PC foil or PE foil) with a first material, especially a thermoplastic.

[0038] The functional display is preferably transparent to the observer in an area outside the uncoated surface structured symbol area of ​​the display surface, so as to reveal the vehicle's road direction or other displays to the viewer in the area behind the functional display.

[0039] According to a preferred design, a plurality of light conductors are provided, the light conductors being arranged such that at least one of the main surfaces of the light conductors faces the main surface of an adjacent light conductor, and the main surfaces are spaced apart by an air gap or a gap formed by a material that is optically thinner than the first and second materials, wherein uncoated symbol regions are arranged relative to each other in a laterally offset manner with respect to the stacking direction of the light conductors, preferably without overlapping. By selectively activating the light source, different on / off states or switching functions can be visualized relatively easily.

[0040] The color of the light incident on the light conductor is preferably different in different light conductors.

[0041] To prevent unwanted light propagation in the optical conductor, especially under the influence of external light, according to a preferred embodiment, the optical conductor is coated with an antireflective coating at at least one end face, preferably the end face opposite to the end face facing the light source. This antireflective coating is also commonly referred to as an anti-reflective coating or compensation layer. The task of the antireflective coating is, for example, to reduce the amount of light reflected into the optical conductor at the coated end face, relative to the uncoated end face, by absorbing light within the coating. For example, the antireflective coating can be applied circumferentially in addition to the light incident area provided for the light from the light source. This antireflective coating, for example, has an optical refractive index numerically between that of air and the material of the optical conductor. The coating is preferably applied using thin-layer techniques, such as physical vapor deposition, thermal evaporation, and sputtering deposition. Attached Figure Description

[0042] The invention and its technical environment will now be explained in detail with the aid of the accompanying drawings. It should be noted that the drawings illustrate particularly preferred embodiments of the invention; however, the invention is not limited to these embodiments. The drawings schematically illustrate:

[0043] Figure 1 A schematic cross-sectional view of a functional display 1 according to an embodiment of the present invention;

[0044] Figure 2 exist Figure 1 The figure shows a perspective cross-sectional view of a functional display 1 according to an embodiment of the present invention;

[0045] Figures 3a-3d A schematic diagram illustrating the manufacturing method according to the present invention. Detailed Implementation

[0046] Figure 1 This schematically illustrates an embodiment of the functional display 1 according to the present invention, the functional display being used to selectively display at least one symbol 7 representing a switching function and / or multiple switching states, as shown in... Figure 2 As can be seen in the three-dimensional illustration. Selective display is not only understood as the selective display of different symbols from a plurality of pre-given symbols, which in the embodiment not shown is achieved by selectively selecting one or more light sources from a plurality of light sources and energizing them, but also as in... Figure 1 and Figure 2In the illustrated embodiment, the symbol 7 is selectively displayed to observer B visually by switching the light source on and off, through activated backlighting, or by turning off the backlighting, making the symbol 7 nearly disappear from observer B's view. For this purpose, the functional display 1 includes at least one planar light conductor 2 formed of at least one transparent or translucent first material. The light conductor has two opposing main surfaces 8 and 9 and at least one end surface 11. In the intended arrangement of the functional display 1, one main surface 8 faces observer B (e.g., a vehicle driver) and serves as the display surface, while the other main surface 9 is arranged away from observer B. The light conductor 2 here has two opposing, parallel main surfaces 8 and 9 connected by end surfaces that form a common edge with the main surfaces 8 and 9 at the narrow and long sides of the light conductor 2. Here, all end surfaces are orthogonal to the two main surfaces 8 and 9 of the light conductor 2. The at least one transparent or translucent material is, for example, a plastic, preferably a thermoplastic, such as polyethylene (PE), polycarbonate (PC), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), acrylonitrile-butadiene-styrene (ABS), or polymethyl methacrylate (PMMA). Main surfaces 8 and 9 are understood as those surfaces of the light conductor 2 having the largest area. Except for the surface structuring described below, main surfaces 8 and 9 are designed to be substantially flat. The light conductor 2 may be provided with a transparent or translucent coating, such as a paint layer, or a foil layer construction, for example, produced by back-injection molding foil. The functional display 1 has at least one light source 5, which is arranged to incident light L from the light source 5 into the light conductor 2 via the end face 11 of the light conductor 2. To improve light incidence and / or to adapt the light radiation characteristics of the light source 5 to the end face 11 determined for allowing light to enter the light conductor 2, a lens and / or baffle may be arranged between the light conductor and the light source, which... Figure 1 and Figure 2 Not shown in the image. The baffle can also be configured to prevent light from spilling out into other light conductors 2 besides the configured light conductor 2 in a functional display 1 having more than one light conductor 2.

[0047] According to the invention, at least one of the main surfaces 8 and 9 of the photoconductor 2 (here, the main surface 8 facing the observer B) is surface-structured by means of a plurality of microstructures 4 introduced into the main surface 8 to refract and / or scatter light. In the illustrated embodiment, the microstructure 4 is understood as a single recess in the main surface 8, with a maximum size in the range of 1 to 50 µm, preferably in the range of 1 to 25 µm. In the illustrated embodiment, the microstructures 4 are preferably arranged in a uniformly spaced manner across the entire surface-structured regions 6a and 6b of the main surface 8. Here, all microstructures 4 are identical in shape and have a consistent orientation and are formed to produce a collimated beam of light L exiting the photoconductor 2, which originates from the light source 5 and has previously entered the photoconductor 2 via the end face 11.

[0048] According to the invention, a coating 3 is also provided that is applied only locally to the surface-structured (i.e., microstructured 4) regions 6a and 6b of the main surface 8, the coating being formed of a transparent or translucent second material, such that in addition to at least one continuous uncoated surface-structured symbol region 6a of the main surface 8, at least one coated surface-structured region 6b remains in the surface-structured regions 6a and 6b. Figure 2 As shown in the three-dimensional cross-sectional view, the coated, surface-structured region 6b surrounds the uncoated, surface-structured symbolic region 6a. To prevent unwanted light propagation in the light conductor 2, especially under the influence of external light, the light conductor 2 has an anti-reflection coating 12 at at least one of its end faces, preferably on the end face 11 opposite to the end face facing the light source 5. This anti-reflection coating is also commonly referred to as an anti-reflection coating or compensation layer. For example, the anti-reflection coating can be applied in a surrounding manner, except for the light incident area provided for the light L of the light source 5.

[0049] When the light source 5 is activated, light L incident on the photoconductor 2 is induced to exit towards the observer B through light refraction and / or light scattering in the uncoated surface-structured symbol region 6a, making the symbol 7 generated and illuminated by the uncoated surface-structured symbol region 6a visible to the observer B. Through light refraction and / or light scattering, surface structuring achieves, for example, enhanced light emission towards the observer B compared to a design involving a flat and thus unstructured main surface 8. This can be explained by the fact that the microstructure 4 enables light L to strike an interface pre-defined by the microstructure 4 at an angle that does not satisfy the total internal reflection condition, causing light L to exit the photoconductor 2 within the region of the microstructure 4.

[0050] The surface-structured regions 6a and 6b have 3D microstructures 4 formed in the same shape, with an average number density of 500 to 7000 per square millimeter, preferably between 1000 and 4000 per square millimeter, on the surface-structured regions 6a and 6b. It has been shown that such a number density generates a brightness distribution sufficient for visual discernibility when the light source 5 is on, while being visually inconspicuous when the light source 5 is off, making the surface-structured regions 6a and 6b indistinguishable at the expected viewing distance for the naked eye, and in particular not obstructing the line of sight that may be seen through the functional display 1 in certain situations.

[0051] Because coating 3 predefines the uncoated surface-structured symbol region 6a, especially its boundaries—that is, the interface design, position, and size between the uncoated surface-structured symbol region 6a and the coated surface-structured region 6b—these factors depend only on the choice of coating method and no longer on the type and implementation of the surface structuring method. This not only simplifies the manufacturing process but also improves the design freedom when displaying symbol 7 by using surface coating as a means of implementing the predetermined design of symbol 7. Furthermore, this creates the possibility of pre-producing uncoated photoconductors 2 for multiple symbols 7 without being forced to associate them with a specific symbol. The functional display 1 can be implemented simply and cost-effectively, providing designers with considerable design flexibility, including the placement of the functional display 1. The functional display 1 exhibits minimal aging effects from light radiation and is relatively energy-efficient. The uncoated surface-structured symbol region 6a can, for example, display the front of symbol 7 as an image, as its opposite illustration, or as a reproduction of its outline.

[0052] refer to Figures 3a to 3d The present invention describes a method for manufacturing a functional display 1, particularly for motor vehicles, for selectively displaying at least one symbol 7 representing a switching function and / or multiple switching states. Figure 3a In the production steps shown, a planar light conductor 2 is produced from a transparent or translucent first material. The light conductor 2 has two opposing main surfaces 8 and 9 and at least one end surface 11. When a functional display is arranged as intended, one main surface 8 forms the display surface facing the observer, and the other main surface is arranged away from the observer. For example, the light conductor 2 can be produced by back-injecting a transparent thermoplastic foil 2a with transparent thermoplastic. Alternatively, the light conductor 2 can also be a layer structure formed by a thermoplastic layer and a coating layer.

[0053] Surface structuring is performed simultaneously or subsequently in time. The results obtained are... Figure 3bAs shown in the figure. Here, the surface structure of the main surface 8 of the photoconductor 2, which is to be arranged facing the observer, is achieved by means of a plurality of microstructures 4 introduced into the main surface 8 to refract and / or scatter light. The microstructure 4 is understood as a single recess in the main surface 8, the maximum size of which is in the range of 1 to 50 µm, preferably in the range of 1 to 25 µm.

[0054] The microstructures are arranged in a uniformly spaced distribution on the structured area of ​​the main surface 8. More preferably, the microstructures 4 are formed in the same shape, wherein a collimated beam of light L is generated that exits from the light conductor 2 and originates from the light source 5 and has previously entered the light conductor 2 via the end face 11.

[0055] As in Figure 3c As a result, the surface-structured regions 6a and 6b of the main surface 8 are subsequently coated only partially with a transparent or translucent second material, leaving at least one continuous uncoated surface-structured symbol region 6a of the main surface 8 and generating at least one coated surface-structured region 6b of the associated main surface 8.

[0056] To prevent unwanted light propagation in the photoconductor, especially under the influence of external light, the photoconductor 2 is coated with an antireflective coating 12 at at least one of its end faces, preferably on the end face 11 opposite to the end face facing the light source 5. This antireflective coating is also commonly referred to as an anti-reflective coating or compensation layer. For example, the antireflective coating can be applied in a circumferential manner from the light incident area provided for the light from the light source 5. This antireflective coating 12, for example, has an optical refractive index numerically between that of air and the material of the photoconductor 2. The coating is preferably applied using a thin-layer coating method, such as physical vapor deposition, thermal evaporation, or sputtering deposition.

[0057] As in Figure 3d As a result, at least one light source 5 is subsequently secured, the light source being arranged to incident light L into the light conductor 2 via the end face 11, such that when the light source 5 is activated, light L incident into the light conductor 2 is caused to exit towards the observer through light refraction and / or light scattering in the uncoated surface-structured symbol region 6a, and the symbol 7 generated and illuminated through the uncoated surface-structured symbol region 6a is visible to the observer. The light source 5 is fixed to its carrier 10, which surrounds the light conductor 2 in a frame shape.

[0058] Because the coating predefines the uncoated surface-structured symbol region 6b, especially its boundaries—that is, the interface design, position, and size between the uncoated surface-structured symbol region 6a and the coated surface-structured region 6b—they depend only on the choice of coating method and no longer on the type of surface structuring method. This not only simplifies the manufacturing process but also improves the design freedom when displaying symbol 7 by using a surface coating as a means of implementing the predetermined design of symbol 7. Furthermore, this creates the possibility of pre-producing photoconductors 2 for multiple symbols without being forced to associate them with a specific symbol. The functional display 1 can be implemented simply and cost-effectively, providing designers with considerable design flexibility, including the placement of the functional display. The functional display 1 exhibits minimal aging effects from light radiation and is relatively energy-efficient. The uncoated surface-structured symbol region 6b can reproduce the symbol, for example, as a frontal image, as its opposite illustration, or as its outline.

Claims

1. A function display (1) for a motor vehicle for selectively displaying at least one symbol (7) representing a switch function and / or multiple switch states, the function display having: At least one planar optical conductor (2) formed of at least one transparent or translucent first material, the optical conductor having two main surfaces (8, 9) opposite to each other and at least one end surface (11), one main surface (8) facing the observer (B) as a display surface and the other main surface (9) facing away from the observer (B); At least one light source (5) is arranged to incident light (L) from the light source (5) into the light conductor (2) via the end face (11); At least one of the main surfaces (8) of the optical conductor (2) is surface-structured by means of a plurality of microstructures (4) introduced into the corresponding main surface (8) to refract and / or scatter light, so as to form a surface-structured region (6a, 6b) of the corresponding main surface (8), wherein the microstructures (4) are disposed on the entire surface of at least one main surface (8) and are uniformly distributed. as well as A coating (3) is applied only locally to the surface-structured regions (6a, 6b) of the main surface (8), the coating being formed of a transparent or translucent second material, such that at least one coated surface-structured region (6b) of the corresponding main surface (8) exists and at least one continuous uncoated surface-structured symbol region of the corresponding main surface (8) remains; wherein, when the light source (5) is activated, light (L) incident on the light conductor (2) is induced to exit toward the observer (B) by light refraction and / or light scattering in the uncoated surface-structured symbol region, such that the symbol (7) generated and illuminated by the uncoated surface-structured symbol region is visible to the observer (B).

2. The functional display (1) according to claim 1, wherein the surface-structured regions (6a, 6b) are produced by embossing and / or molding.

3. The functional display (1) according to any one of the preceding claims, wherein the coating (3) is formed to fill microstructures disposed in a coated surface-structured region (6b) by means of the coating (3).

4. The functional display (1) according to claim 1, wherein the surface-structured regions (6a, 6b) have 3D microstructures (4) formed in the same shape, the average number density of the microstructures on the surface-structured regions (6a, 6b) being between 500 and 7000 per square millimeter.

5. The functional display (1) according to claim 4, wherein the average number density of the microstructures on the surface-structured regions (6a, 6b) is in the range of 1,000 to 4,000 per square millimeter.

6. The functional display (1) according to any one of claims 4 or 5, wherein the size of the microstructure (4) is in the range of 1 to 25 μm.

7. The functional display (1) according to claim 1, wherein the second material is a transparent curing paint, a transparent curing adhesive, or a transparent curing resin.

8. The functional display (1) according to claim 1, wherein the area ratio of all uncoated surface-structured symbol regions in the entire surface-structured region (6a, 6b) of the corresponding main surface (8) is less than 0.

5.

9. The functional display (1) according to claim 8, wherein the area ratio of all uncoated surface-structured symbol regions in the entire surface-structured region (6a, 6b) of the corresponding main surface (8) is less than 0.

3.

10. The functional display (1) according to claim 1, wherein the first material and the second material each have an optical refractive index, wherein the optical refractive indices differ from each other by no more than 0.

2.

11. The functional display (1) according to claim 10, wherein the optical refractive indices differ from each other by no more than 0.

1.

12. The functional display (1) according to claim 1, wherein the optical conductor (2) has at least one foil (2a).

13. The functional display (1) according to claim 1, wherein the functional display is transparent to the observer (B) in the area outside the uncoated surface structured symbol area of ​​the display surface.

14. The functional display (1) according to claim 1, wherein a plurality of light conductors (2) are provided, the light conductors being arranged such that at least one of the main surfaces of the light conductors (2) faces the main surface of an adjacent light conductor and the main surfaces are spaced apart by an air gap or by a gap formed by a material that is optically thinner than the first material and the second material, wherein uncoated surface-structured symbol regions are arranged to be laterally offset from each other relative to the stacking direction of the light conductors.

15. The functional display (1) according to claim 14, wherein the uncoated surface-structured symbol regions are arranged so as not to overlap with each other relative to the stacking direction of the photoconductor.

16. The functional display (1) according to claim 14 or 15, wherein the color of the light (L) incident on the light conductor (2) is different in different light conductors.

17. An operating element having a functional display (1) according to any one of the preceding claims and an operating component, wherein a main surface (8) serving as a display surface forms an operating surface of the operating element determined for contacting or actuating the operating component.

18. A steering wheel for a motor vehicle, the steering wheel having the operating elements according to claim 17.

19. A method for manufacturing a functional display (1) for a motor vehicle, the functional display being used to selectively display at least one symbol (7) representing a switching function and / or multiple switching states, the method comprising the steps of: At least one planar optical conductor (2) is produced from at least one transparent or translucent first material, the optical conductor having two main surfaces (8, 9) opposite to each other and at least one end surface (11), wherein, in the case of the functional display (1) being arranged as intended, one of the main surfaces (8) forms a display surface facing the observer (B) and the other main surface (9) is arranged to face away from the observer (B). Simultaneously or subsequently, surface structuring is performed, wherein at least one of the main surfaces (8) of the optical conductor (2) is surface-structured by means of a plurality of microstructures (4) introduced into the respective main surface (8) to refract and / or scatter light, so as to form a surface-structured region (6a, 6b) of the respective main surface (8), wherein the microstructures (4) are disposed on the entire surface of at least one main surface (8) and are uniformly distributed. A coating (3) is formed by subsequently coating only the surface-structured regions (6a, 6b) of the corresponding main surface (8) with a transparent or translucent second material, such that at least one coated surface-structured region (6b) of the corresponding main surface (8) exists and at least one continuous uncoated surface-structured symbol region of the corresponding main surface (8) is retained. At least one light source (5) is secured, the light source being arranged to incident light (L) into the light conductor (2) via the end face (11) of the light conductor (2), such that when the light source (5) is activated, light refraction and / or light scattering in the uncoated surface-structured symbol region causes the light (L) incident into the light conductor (2) to exit toward the observer (B), and such that the symbol (7) generated and illuminated through the uncoated surface-structured symbol region is visible to the observer (B).

20. The method of claim 19, wherein the surface structuring is produced by embossing and / or molding.

21. The method according to claim 19 or 20, wherein the coating is performed such that the coating (3) fills the microstructure (4) disposed in the coated surface-structured region (6b).

22. The method according to claim 19, wherein the surface-structured regions (6a, 6b) have 3D microstructures (4) formed in the same shape, the average number density of the microstructures on the surface-structured regions (6a, 6b) being between 500 and 7000 per square millimeter.

23. The method of claim 22, wherein the average number density of the microstructures on the surface-structured regions (6a, 6b) is in the range of 1,000 to 4,000 per square millimeter.

24. The method according to claim 22 or 23, wherein the size of the microstructure (4) is in the range of 1 to 25 μm.

25. The method of claim 19, wherein the coating comprises applying a clear curing varnish or a clear curing adhesive or a clear curing resin and curing thereon.

26. The method according to claim 19, wherein the area ratio of all uncoated surface-structured symbol regions in the entire surface-structured region (6a, 6b) of the corresponding main surface (8) is less than 0.

5.

27. The method of claim 26, wherein the area ratio of all uncoated surface-structured symbol regions in the entire surface-structured region (6a, 6b) of the corresponding main surface (8) is less than 0.

3.

28. The method of claim 19, wherein the first material and the second material each have an optical refractive index, wherein the optical refractive indices differ from each other by no more than 0.

2.

29. The method of claim 28, wherein the optical refractive indices differ from each other by no more than 0.

1.

30. The method according to claim 19, wherein the optical conductor (2) is produced by back-injection foil (2a) or foil layer construction.

31. The method of claim 19, wherein the manufactured functional display (1) is arranged to be transparent to the observer (B) in a region outside the uncoated surface structured symbol area of ​​the display surface.

32. The method according to claim 19, wherein a plurality of optical conductors (2) are arranged such that at least one of the main surfaces of the optical conductors (2) faces the main surface of an adjacent optical conductor (2) and the main surfaces are spaced apart by an air gap or by a gap formed of a material that is optically thinner than the first material and the second material, wherein uncoated surface-structured symbol regions are arranged to be laterally offset from each other relative to the stacking direction of the optical conductors (2).

33. The method of claim 32, wherein the uncoated surface-structured symbol regions are arranged so that they do not overlap with each other relative to the stacking direction of the photoconductor (2).

34. The method according to claim 32 or 33, wherein the color of the light (L) incident on the light conductor (2) is different in different light conductors (2).

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