Surface lighting element and interior trim element for a motor vehicle with a surface lighting element

Abstract

The invention relates to a surface lighting element (1) and an interior trim element for a motor vehicle with such a surface lighting element (1). The surface lighting element (1) has a light source (3) and a light guide film (5) for distributing light in a main area of ​​the light guide film (5). A central light emission direction of the light source (3) is oriented, at least in a portion of the light source (3), substantially perpendicular to the main area of ​​the light guide film (5) in the direction of a lighting direction (P2) of the surface lighting element (1). The light guide film (5) has a recess above the light source (3) in which a deflecting mirror (6) for deflecting the light into the light guide film (5) is arranged. The recess, the deflecting mirror (6), and a surrounding portion (9) of the light guide film are covered by a light-guiding aperture (10).The aperture (10) serves to receive light from the light guide film (5) and to couple out light at least substantially perpendicular to the main extension surface in the direction of illumination (P2) of the area light element (1).

Description

[0001] The present invention relates to a surface lighting element and an interior trim element for a motor vehicle equipped with such a surface lighting element. A surface lighting element in this sense is an element that illuminates over a surface, for example in contrast to a point light source such as a single LED chip or in contrast to the filament of a conventional incandescent lamp.

[0002] Uniform surface illumination or backlighting is not easily achieved with conventional incandescent lamps or individual LEDs. Therefore, film lighting systems are currently used, in which light is directed onto a transverse or narrow side of a film using a so-called side-firing LED. For example, a motor vehicle with a light guide is known from DE 20 2016 003 741 U1. Light is guided within the light guide, and light is coupled out of the light guide by means of an output structure to illuminate the interior of the motor vehicle. The light guide is designed as a film. One end face of this film forms an input section for coupling light into the film.

[0003] A disadvantage of such side-firing arrangements is that uniform light emission from the film is only possible up to a limited distance from the light source, i.e., from an edge of the respective film. Since one cannot shine light arbitrarily far or deep into the film material from the side or edge, the achievable size of the film, and thus the illuminated area, is limited – at least if uniform brightness across the entire surface is desired.

[0004] From US patent 8,641,219 B1, a display arrangement with a backlight module for illuminating a display field is known. The backlight module comprises a light source that illuminates a reflective reflector arranged in a recess of a light guide. The reflector is preferably conical, pyramidal, or circular in shape and distributes the light emitted by the light source within the light guide. A diffuser layer is arranged between the light guide and the display field.

[0005] A backlighting module is also known from US patent 2009 / 0034264 A1. This backlighting module comprises a reflector arranged between a light source illuminating the reflector and a light guide plate, and in particular, integrated into a recess in the light guide plate. The reflector distributes the light emitted by the light source within the light guide. To adjust the scattering of the light from the light source within the light guide plate, the backlighting module also includes a microprism layer, a polarizing layer, and a diffuser layer.

[0006] US patent 2010 / 0008628 A1 discloses a lighting structure with an LED embedded in a light guide. The LED illuminates a parabolic mirror integrated into the light guide, which distributes the emitted light from the LED within the light guide. An absorber is positioned directly above the mirror, ensuring that light of a desired intensity is emitted in this area.

[0007] The object of the present invention is to enable space-efficient, uniform illumination of larger areas. This object is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments and further developments of the present invention are specified in the dependent claims, in the description, and in the figures.

[0008] A surface luminaire element according to the invention comprises a light source and a light guide film. The light guide film is arranged to receive light emitted by the light source and to distribute the light in a principal extension area or principal extension plane of the light guide film. The light guide film has an output structure for coupling light from a top surface of the light guide film into a luminaire direction of the surface luminaire element that extends at least substantially perpendicular to the principal extension area, at least in the region of the light source. For the purposes of the present invention, a film, in particular the light guide film, is meant to be a material or component that is thin relative to its size. In this case, the light guide film can, for example, have a thickness or material thickness in the range of 0.1 mm to several millimeters, but an area of ​​several square centimeters.The optical fiber film can preferably be flexible, i.e., bendable, although this is not necessary. The principal extension surface or principal extension plane can be curved if the optical fiber film is curved, bent, or convex, for example, following a 3D contour of a control element or other component.

[0009] A direction or extent of the principal extent surface is therefore to be understood as lying in or on the respective surface or component, in this case, in or on the material of the optical fiber itself, and can therefore follow a curvature, bend, or warp of this component or material. Directional specifications that refer to an angle of the respective direction with respect to the principal extent surface or the top surface of the optical fiber are to be understood as referring to a local, i.e., limited, sub-region of the optical fiber that exhibits no or only a relatively small curvature over its extent. Likewise, the directional specification can refer to a local tangent plane to the respective component.A direction that is at least substantially perpendicular to the principal extension surface or the top surface can, for example, refer to a local tangent plane to the principal extension surface or top surface of the optical fiber film. The term "at least substantially" can, in particular, mean that the respective direction may deviate from the actual perpendicular by, for example, up to 10° or up to 20°. The same applies to the other directions or directional specifications mentioned here.

[0010] In the surface lighting element according to the invention, the light source is arranged such that its central light emission direction is aligned at least substantially perpendicular to the main extension surface in the direction of the illumination direction of the surface lighting element, at least in the area of ​​the light source.

[0011] The central direction of light emission from the light source is defined by a central ray (which may be imaginary) that is spatially centered within a beam, cone, or field of light emanating from the light source. The light source can, for example, be a point light source and include an optical element, such as a lens or prism, for beam shaping, particularly for beam expansion, i.e., for generating a cone of light with a non-zero divergence. Due to the intended arrangement, the light source thus emits light at least along its central direction of emission, essentially perpendicularly, towards a plane or surface defined by the principal extent surface of the optical fiber or its upper surface within the vicinity of the light source.

[0012] In a particularly preferred embodiment, the light source is designed as a so-called top-fire LED or top-looker LED. This is particularly noticeable in contrast to the conventionally used side-fire LEDs for film illumination. A top-fire LED is a light-emitting diode that emits light upwards and not sideways, i.e., perpendicular to the local principal direction of the light guide film and not parallel to it. Top-fire LEDs have the advantage that they are typically brighter than conventional side-fire LEDs and are available on the market in a wider selection and variety. Furthermore, top-fire LEDs can be positioned not only at the edge of the light guide film but at virtually any point on or within its principal surface.With conventional film lighting, such an arrangement could not be used, because when viewed from outside the surface lighting element, a bright spot of light would appear on the top surface of the light guide film, i.e., the surface lighting element, in the area of ​​the light source, thus preventing uniform illumination of the light guide film across its entire main surface. Even a possible local covering of the light spot would not result in uniform or homogeneous brightness across the main surface of the light guide film, since the covering would block the light and a halo—a ring that is brighter relative to the surroundings—would typically form around the covering.

[0013] To address these problems, the surface lighting element according to the invention further provides that the light guide film above the light source has a recess in which a deflecting mirror is arranged to deflect the light emitted by the light source into the light guide film.

[0014] The deflecting mirror deflects the light, for example, perpendicular to the direction of light emission, so that it can then spread within the light guide film along the main extensional surface.

[0015] Preferably, the deflecting mirror can be designed to be opaque, which advantageously allows as large a proportion as possible of the light emitted by the light source to be coupled into the light guide film in the direction of the main extension surface.

[0016] The deflecting mirror can have one or more reflective surfaces tilted at an angle of 0° to 90° relative to the main surface or the top surface of the light guide film in the area of ​​the light source. These surfaces are also positioned at an angle of 0° to 90° relative to the central light emission direction of the light source. The deflecting mirror thus redirects or deflects the light emitted by the light source, preventing the formation of the described bright spot above the light source. In this sense, the deflecting mirror can act as a cover for the light source. Since the deflecting mirror is positioned in a recess, such as a tapered section or a hole, in the light guide film, a local thickening of the surface lighting element in the area of ​​the mirror and the light source can be advantageously avoided, thus saving space or height.

[0017] To achieve uniform brightness or illumination of the surface lighting element despite the deflecting mirror positioned above the light source, the invention provides that the recess in the light guide film, the deflecting mirror, and a surrounding portion of the light guide film are covered by a light-guiding aperture. The aperture is arranged to couple light in or receive it from the light guide film. Furthermore, the aperture is designed to couple light out at least substantially perpendicular to the main extensional surface in the direction of illumination of the surface lighting element. The aperture can preferably be surface-mounted on the light guide film or embedded in it, thus extending at least locally along or parallel to the main extensional surface or top surface of the light guide film.In the portion of the optical fiber film surrounding the recess or deflecting mirror, which is covered by the aperture, light can pass from the optical fiber film into the aperture, i.e., be coupled into the aperture. Due to the optical conductivity of the aperture, this light, having passed through or been coupled into the aperture, is distributed in a principal plane or surface of the aperture over a certain extent, particularly its entire extent.

[0018] Like the light guide film, the aperture has an output coupling structure for coupling out the light, at least essentially in the central light emission direction of the light source.

[0019] The aperture can also be designed as a light-guiding film or light guide element. However, the aperture can be made of a different material or have different material properties, for example, a different refractive index, than the light-guiding film. This advantageously allows for a particularly precise adaptation of the aperture's optical properties, which in turn enables uniform brightness or luminance to be achieved across the entire extent of the surface lighting element. The portion of the light-guiding film surrounding the recess and the deflecting mirror, which is covered by the light-guiding aperture, corresponds precisely to the area in which the aforementioned halo forms or would form.

[0020] The design of the surface lighting element according to the invention, as described here, makes it possible to arrange the light source, or even several corresponding light sources, across the entire surface of the surface lighting element and not just at its edge or at the edge of the light guide film, while still achieving uniform brightness or luminance. This allows for much larger surface areas to be illuminated compared to conventional film lighting with side-firing LEDs, and these areas can also exhibit greater brightness or luminance. Compared to conventional lighting for larger areas, where, for example, several fluorescent tubes are arranged behind a matte, semi-transparent component, the surface lighting element according to the invention saves installation space, thus enabling more compact surface lighting.The surface lighting element according to the invention thus allows for the uniform and particularly space-saving illumination of virtually any size area. The surface lighting element according to the invention can therefore be used in a wide variety of areas where lighting or illumination is desired, for example, for residential lighting, interior lighting of a motor vehicle, outdoor lighting for advertising boards, and / or for a wide variety of other applications.

[0021] A further advantage of the surface lighting element according to the invention is that the size of the light source plays only a minor role, since complete illumination or light coupling across the entire thickness of the light guide film can be achieved through a suitable arrangement and design of the deflecting mirror. Thus, unlike conventional film lighting with side-firing LEDs, the thickness or material thickness of the light guide film does not need to be adapted to the size or height of the respective side-firing LED or its chip or crystal. Therefore, with the surface lighting element according to the invention, different types and shapes of light sources, as well as different light guide films or thicknesses (i.e., material thicknesses), can be advantageously used and combined flexibly.This results in the surface lighting element according to the invention being more flexible in its application compared to conventional film lighting systems, meaning it is suitable for a wider range of applications and allows the use of larger and / or more powerful light sources for brighter film lighting, i.e., higher luminance. This offers significant advantages, particularly for colored lighting.

[0022] In a further advantageous embodiment of the present invention, the deflecting mirror is conical, pyramidal, or wedge-shaped. In this configuration, a tip or edge of the deflecting mirror faces the light source, and an opposing base surface of the mirror is arranged at least substantially parallel to the top surface of the optical fiber film in the region of the deflecting mirror. The deflecting mirror in this sense can be a single component or assembly, or it can be composed of several individual mirrors or several individual reflective surfaces. One or more reflective surfaces of the deflecting mirror can be flat or curved. Overall, this advantageous configuration allows the light emitted by the light source to be coupled into the optical fiber film at an angle optimal for the distribution of the light within the optical fiber film.The conical, pyramidal or wedge-shaped design of the deflecting mirror proposed here advantageously enables the coupling of light into the optical fiber film in a particularly simple and mechanically stable manner.

[0023] The angle at which the mirror surfaces are positioned relative to the main extensional surface of the light guide film or a local sub-area of ​​the light guide film and to the central light emission direction of the light source can be adjusted or selected, for example, depending on the thickness of the light guide film. Thus, the embodiment proposed here can be advantageously used for various embodiments of the surface lighting element according to the invention. Furthermore, the embodiment proposed here enables particularly simple and reliable manufacturing of the surface lighting element, since the deflecting mirror can, for example, be inserted into the recess of the light guide film from above, i.e., from the outside.

[0024] Since the tip or edge of the deflecting mirror can enter the recess first, an inaccuracy in positioning the deflecting mirror over the recess is tolerable. Due to the pointed shape of the deflecting mirror, such an inaccuracy is automatically compensated for when the deflecting mirror is inserted or lowered into the recess.

[0025] In a further advantageous embodiment of the present invention, the surface lighting element comprises a printed circuit board (PCB) on which the light guide film is arranged. The PCB has a through-hole in which the light source is located or through which the light source shines from a side of the PCB opposite the light guide film. This advantageously allows the light guide film to lie flat on the PCB over its entire extent or area. Furthermore, it advantageously saves installation space, in particular enabling the surface lighting element to have the smallest possible extent or thickness perpendicular to the main area of ​​the light guide film. Another advantage of the embodiment proposed here is that it allows for single-sided assembly of the PCB, which advantageously saves costs and manufacturing effort.This can be the case, in particular, if other electrical or electronic components, such as contacts, a power supply or voltage regulator for the light source, and / or similar items, are to be arranged on the side of the circuit board facing away from the light guide film. However, it may alternatively be possible to arrange the light source on the side of the circuit board facing the light guide film.

[0026] In a further advantageous embodiment of the present invention, the optical fiber film is multilayered, i.e., multilayered or multicomponent, and comprises at least one specular or reflective layer, a waveguide layer, a diffuser layer, and / or a polarizing layer. These layers are preferably arranged perpendicular to the main surface of the optical fiber film in the order mentioned herein. In other words, the diffuser layer or the polarizing layer faces the top surface of the optical fiber film or forms this top surface, while the specular layer is arranged on the side facing the light source, preferably as the underside of the optical fiber film opposite the top surface. The specular layer is arranged such that it reflects incident light towards the top surface, i.e., into the waveguide layer.The waveguide layer itself can be multilayered or, for example, have several areas with different refractive indices. Overall, the proposed design advantageously enables a particularly effective distribution of light in or along the main extensional surface of the light guide film, as well as a particularly high and uniform brightness of the surface lighting element or the top side of the light guide film.

[0027] In a further advantageous embodiment of the present invention, the aperture is multilayered, i.e., multi-layered or multi-component. For example, the aperture can have a unidirectional reflective film or layer, which is arranged, in particular, on a lower side of the aperture, i.e., on a side facing the upper side of the light guide film. This unidirectional reflective film or layer can then allow light passing from the light guide film into the aperture to pass through, while reflecting light incident on the reflective film or layer back into the aperture. This can advantageously enable the light received from the light guide film to be distributed as effectively and uniformly as possible within the aperture. Likewise, the aperture can have one or more lens films or layers and / or at least one layer with a microstructure.These can advantageously enable particularly effective or needs-based coupling of light from the light guide film and / or coupling of light from the aperture in the direction of illumination of the surface light element. To distribute the light as evenly as possible within the aperture, the aperture, like the light guide film, can incorporate a waveguide layer. The aperture and / or the light guide film can be made, at least partially, from a plastic such as polycarbonate (PC) or polymethyl methacrylate (PMMA). This advantageously allows for cost-effective manufacturing using established methods.

[0028] In a further advantageous embodiment of the present invention, the aperture comprises a layer of optically clear adhesive (OCA) and a film layer. Due to the adhesive properties of the optically clear adhesive (OCA), a particularly simple aperture design and a particularly simple and cost-effective fastening of the aperture can be achieved. The optically clear adhesive can thus serve both to hold the aperture to the other parts of the surface illumination element, i.e., to the deflecting mirror and / or to the section of the light guide film, and also to hold the film layer to the layer formed by the OCA adhesive on the opposite side.This means that further fastening elements or fasteners and corresponding process steps in a manufacturing process for producing the surface lighting element can be omitted, i.e., saved.

[0029] The OCA adhesive layer can itself comprise several sub-areas or components, for example, areas with different optical properties, particularly different refractive indices. This advantageously allows for a particularly effective distribution of light across a portion or surface of the aperture. Similarly, the film layer can have a different refractive index than the OCA adhesive. This allows the optical behavior of the aperture, especially with regard to light transmission and light extraction, to be adapted to specific conditions or requirements in order to achieve the most uniform brightness or luminance possible of the surface lighting element.

[0030] In a further advantageous embodiment of the present invention, the light source is configured as an RGB LED and comprises several chips designed to emit light of different colors. In particular, the light source can, for example, have one LED or one chip each for the colors red, green, and blue. In principle, it would also be possible to arrange several light sources for the different colors side by side, each with the described arrangement of mirror and aperture. However, the embodiment provided here, in which the single light source comprises several chips, i.e., several partial light sources on a common die, advantageously allows for savings in components and manufacturing effort, as well as improved light mixing and thus improved color control and color homogeneity.The use of such an RGB LED for film illumination is only made possible by the present invention, i.e., the inventive design of the surface illumination element, since the additional size of the light source due to the multiple chips usually precludes its use in a conventional side-firing configuration, or only allows for undesirably thick light guide films. Additionally, the light source can include one or more further chips, for example, at least one additional chip for emitting white light, resulting in an RGBW LED or arrangement. This additional chip or these additional chips advantageously enable improved control of the light source's brightness without affecting color selection or control, or overloading the chips designated for the individual colors.

[0031] In a further advantageous embodiment of the present invention, the light guide foil has an extent of more than 100 mm, preferably at least or more than 150 mm, in its main extension area in two dimensions.

[0032] The surface lighting element features several light sources, each with its own deflecting mirror and aperture, spatially distributed across its main surface area. This spatially distributed arrangement of multiple light sources allows for the achievement of uniform and exceptionally high brightness or luminance across the relatively large surface area of ​​the light guide film and thus the surface lighting element, despite its considerable size. In particular, this method allows for significantly higher brightness or luminance levels and significantly improved uniformity of brightness across the surface of the element compared to conventional side-firing film lighting systems.The proposed design allows the surface lighting element according to the invention to be used for a multitude of new applications for which film lighting was previously impractical. An example of this is a lighting surface on the headliner of a motor vehicle, where conventional non-film-based lighting is generally not practical due to limited installation space and, potentially, a curved roof.

[0033] Another aspect of the present invention is an interior trim element for a motor vehicle. The interior trim element according to the invention comprises a surface element, at least partially translucent, which, in the installed position of the interior trim element, faces the interior of the motor vehicle, and a lighting device arranged on an inner surface of the surface element that, in the installed position, faces away from the interior. According to the invention, the lighting device is or comprises a surface lighting element according to the invention for at least partially back-illuminating the surface element, particularly in the translucent areas.The interior trim element can be, for example, a control element, such as a switch or lever, or, for example, a part of the interior trim of the motor vehicle, or, for example, a part of a center console or instrument panel, a part of the roof or floor of the motor vehicle, or the like. The use of the surface lighting element according to the invention as such an interior trim element for a motor vehicle is particularly advantageous because it offers a multitude of advantageous design possibilities, since the size or extent of the surface lighting element is not limited by the beam depth inherent in conventional side-firing arrangements.

[0034] Furthermore, the surface lighting element according to the invention can achieve brightness levels or luminances that allow the switching state of the surface lighting element to be recognized even in daylight, i.e., in a correspondingly high ambient light level in the vehicle. In other words, due to the particularly high achievable brightness or luminance of the surface lighting element according to the invention, it is possible to use the surface lighting element according to the invention to indicate functions in the vehicle even in relatively high ambient light levels, since it remains recognizable to a user whether the surface lighting element is switched on or off, i.e., illuminated or not illuminated.

[0035] The invention also includes further developments of the interior fitting element according to the invention, which have features as described in connection with the further developments of the surface lighting element according to the invention, and vice versa. For this reason, the corresponding further developments are not described separately here for all aspects of the present invention.

[0036] An embodiment of the invention is described below. The following is shown: Fig. 1 a schematic side sectional view of a surface lighting element; Fig. 2 A schematic side exploded view to illustrate the layer structure of a light guide film.

[0037] The embodiment described below is a preferred embodiment of the invention. In this embodiment, the described components each represent individual features of the invention that can be considered independently of one another. Each of these features further develops the invention independently and can therefore be considered part of the invention individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by other features of the invention already described.

[0038] In the figures, functionally identical elements are each provided with the same reference symbols.

[0039] Fig. Figure 1 shows a schematic side sectional view of a surface-mounted light source 1. The surface-mounted light source 1 has a printed circuit board 2 with a through-hole in which a top-firing LED 3 is mounted. In contrast to an on-board version, where the top-firing LED would be mounted on the top side of the printed circuit board 2, the through-hole design shown here allows for a reduction in overall height. A ground contact 4 for the top-firing LED 3 is indicated on the underside of both the LED and the printed circuit board 2. This ground contact 4 can be used, for example, to supply the LED 3 with electrical power. It can also serve as a support or holder for the LED 3.

[0040] Furthermore, the surface light element 1 comprises a light guide film 5, which is placed on or attached to the top surface of the circuit board 2. The light guide film 5 has a recess, for example a hole, in the area of ​​the top-firing LED 3. A conical deflecting mirror 6 is arranged in this recess such that its apex faces the top-firing LED 3 and an opposite base surface faces away from the top-firing LED 3. The deflecting mirror 6 has one or more mirror surfaces 7, which are tilted or obliquely arranged with respect to a principal plane or surface of both the circuit board 2 and the light guide film 5. In this case, the mirror surface 7 is formed by a lateral surface of the conical deflecting mirror 6.

[0041] The topfire LED 3 is arranged and oriented such that its light emission direction points upwards, i.e., towards the deflecting mirror 6. A central light emission direction, i.e., the direction of a central ray of a light beam, beam, or cone emitted by the topfire LED 3, extends, at least in the area of ​​the topfire LED 3, i.e., in the area of ​​the recess in the light guide film 5, at least substantially perpendicular to the main surface of the light guide film 5. The light emitted by the topfire LED 3 thus strikes the mirror surface 7 and is deflected towards the light guide film 5, or rather towards its main surface, i.e., it is emitted or coupled into the light guide film 5. The deflecting mirror 6 is designed as a 90° omnidirectional reflector.A space between the topfire LED 3 and the deflecting mirror 6 can be used to adjust or set the optical behavior of the surface lighting element 1 and / or, depending on the manufacturing process of the surface lighting element 1, can be, for example, filled with air, filled with a transparent material or filled with the light guide film 5.

[0042] The path of light emitted by the top-fire LED 3 into the light guide film 5 is shown schematically here by arrows P1. The light is then distributed across the main surface of the light guide film 5 and coupled out via a corresponding coupling structure from a top surface 8 of the light guide film 5 facing away from the circuit board 2. This results in a direction of illumination of the surface light element 1 that is at least locally, and substantially, perpendicular to the top surface 8. This direction is shown schematically here by arrows P2, of which only some are labeled.

[0043] Both the circuit board 2 and the light guide film 5 can be curved or bent, which means that in areas of the surface light element 1 remote from the topfire LED 3, its direction of illumination can extend at an angle other than 0° to the direction of light emission of the topfire LED 3. For each local section of the light guide film 5, however, the direction of illumination is still at least substantially perpendicular to the top surface 8 of the light guide film 5. This does not preclude the possibility that light can also be coupled out or emitted from the top surface 8 at other angles.

[0044] Without further measures, no light would escape from the area of ​​the deflecting mirror 6, i.e., from its base surface, and a light spot or halo 9 would form around the deflecting mirror 6, resulting in uneven brightness across the entire surface of the area light source 1. To prevent this and achieve uniform brightness, a light-guiding aperture 10 is provided, which covers the deflecting mirror 6 and thus also the recess in the light guide film 5, as well as a surrounding portion of the light guide film 5. The aperture 10 therefore functions to conceal the halo 9 and simultaneously absorb any excess light from the light guide film 5, distribute it evenly across the aperture 10, and couple it out from an upper surface 11 in the direction of illumination of the area light source 1, as also indicated here by arrows P2.Thus, the light-guiding aperture 10 also illuminates an area of ​​the surface lighting element 1 that lies behind the deflecting mirror 6 from the perspective of the topfire LED 3.

[0045] The in Fig. The representation shown can be viewed as a partial view, so that the arrangement shown can continue, for example, to the left and right, and in particular regularly. Thus, several arrangements, each consisting of a corresponding top-firing LED 3, a deflecting mirror 6, and a light-guiding aperture 10, can be spatially distributed over the entire surface of the area lighting element 1.

[0046] Fig.Figure 2 shows a schematic side exploded view of the light guide film 5. The light guide film 5 has a multi-layered structure. Starting from the circuit board 2, the light guide film 5 first comprises a mirror layer 12 and subsequently a waveguide layer 13. Light guided in the waveguide layer 13, which strikes the mirror layer 12 in the direction of the circuit board 2, is reflected back into the waveguide layer 13 and thus towards the top surface 8 of the light guide film 5. This ensures that as much of the light as possible emitted by the top-fire LED 3 actually emerges from the top surface 8 for its intended illumination purpose and is not absorbed by the circuit board 2. Opposite the mirror layer 12, a diffuser layer 14 adjoins the waveguide layer 13.The diffuser layer 14 can scatter light traveling towards the top surface 8 to achieve the most homogeneous illumination effect possible from the surface light source 1. A polarizing layer 15 is attached to the outside of the diffuser layer 14, which further improves the optical performance, i.e., the illumination characteristics of the surface light source 1. The layers 12, 13, 14, and 15, shown here spaced apart in an exploded view, lie close together in the actual light guide film 5 to minimize, for example, scattering losses and internal reflections.

[0047] Overall, the examples described show how space-efficient, uniform lighting can be achieved even over larger areas. Reference symbol list 1 surface lighting element 2 circuit boards 3 Topfire LEDs 4. Ground contact (for LED 3) 5 Light guide film 6 deflecting mirrors 7 Mirror surface 8 Top 9 Halo 10 aperture 11 Aperture top 12 Mirror layer 13 Waveguide layer 14 Diffuser layer 15 Polarization layer P1, P2 arrows

Claims

[1] Area luminaire (1) comprising a light source (3) and a light guide film (5) which is arranged to receive light (P1) emitted by the light source (3) and to distribute the light (P1) in a principal extent surface of the light guide film (5), wherein the light guide film (5) has an output coupling structure for coupling light from a top surface (8) of the light guide film (5) into a luminaire direction (P2) of the area luminaire (1) extending in the region of the light source (3) at least substantially perpendicular to the principal extent surface, wherein - the light source (3) is arranged such that its central light emission direction is at least substantially perpendicular to the main extensional surface in the direction of the luminous direction (P2) of the surface luminaire element (1), at least in the area of ​​the light source (3), - the light guide film (5) has a recess above the light source (3) in which a deflecting mirror (6) is arranged to deflect the light emitted by the light source (3) into the light guide film (5), characterized by , that - the recess, the deflecting mirror (6) and a surrounding partial area (9) of the light guide film (5) are covered by a light-guiding aperture (10), wherein the partial area (9) of the light guide film (5) surrounding the recess and the deflecting mirror (6), which is covered by the light-guiding aperture (10), corresponds precisely to the area in which a halo is formed, wherein the aperture is arranged to receive light (9) from the light guide film (5) and is designed to couple out light at least substantially perpendicular to the main extensional surface in the illuminating direction (P2) of the area illuminating element (1), wherein the aperture (10) has a coupling structure for coupling out the light at least substantially in the central light emission direction of the light source (3). [2] Surface lighting element (1) according to claim 1, characterized by , that the light source (3) is designed as a top-fire LED. [3] Surface lighting element (1) according to one of the preceding claims, characterized by , that the deflecting mirror (6) is cone-, pyramid- or wedge-shaped, wherein a tip or an edge of the deflecting mirror (6) faces the light source (3) and an opposite base surface of the mirror is arranged at least substantially parallel to the top surface (8) of the light guide film (5). [4] Surface lighting element (1) according to one of the preceding claims, characterized by , that the surface lighting element (1) has a printed circuit board (2) on which the light guide film (5) is arranged, wherein the printed circuit board (2) has a hole in which the light source (3) is arranged or through which the light source (3) shines from a side of the printed circuit board (2) opposite the light guide film (5). [5] Surface lighting element (1) according to one of the preceding claims, characterized by, that the optical fiber film (5) is multilayered and has at least a reflective layer (12) and a waveguide layer (13) as well as a diffuser layer (14) and / or a polarization layer (15). [6] Surface lighting element (1) according to one of the preceding claims, characterized by , that the aperture (10) has a multi-layered structure. [7] Surface lighting element (1) according to one of the preceding claims, characterized by , that the aperture (10) has a layer of an optically clear adhesive and a film layer. [8] Surface lighting element (1) according to one of the preceding claims, characterized by , that the light source (3) is designed as an RGB LED and has several chips which are designed to emit light of different colors. [9] Surface lighting element (1) according to one of the preceding claims, characterized by, that the light guide foil (5) has an extent of more than 100 mm in each of its main extension area in two dimensions, in particular more than 150 mm in each, and the area lighting element (1) has several light sources (3) arranged spatially over the main extension area, each with a deflecting mirror (6) and a aperture (10). [10] Interior trim element for a motor vehicle, comprising a surface element which, in its installed position, faces an interior of the motor vehicle and is at least partially translucent, and a lighting device which is arranged on an inner side of the surface element which, in its installed position, faces away from the interior, characterized by , that the lighting device comprises a surface lighting element (1) according to one of the preceding claims for at least partially back-illuminating the surface element.

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