Luminous film for radiating light in a directed manner
Patent Information
- Application Number
- EP2022706846
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-02-21
- Publication Date
- 2025-01-01
AI Technical Summary
Conventional luminous films used outdoors, such as on buildings, suffer from energy inefficiency and light pollution due to light being emitted in undesired directions, as viewers often observe from different angles, resulting in wasted energy and unnecessary light emission.
A luminous film with a large number of light-emitting diodes arranged on a carrier layer, featuring a micro-optical layer that deflects light emission away from the surface normal, reducing unwanted light emission and enhancing energy efficiency by directing light towards the intended target, with additional micro-optical layers and a diffuser layer for adaptive radiation characteristics and uniform illumination.
The solution significantly reduces energy consumption and light pollution by directing light emissions efficiently, doubling luminosity with the same energy for horizontal illumination and quadrupling it below the horizontal, while reducing energy requirements and light pollution.
Smart Images
Figure 1.1
Abstract
Description
[0001] Luminous film for directed light emission
[0002] Background of the invention
[0003] The invention relates to a luminous film with a plurality of light-emitting diodes arranged on a carrier layer, and with at least one first micro-optical layer for deflecting the light emitted by the light-emitting diodes.
[0004] Such a luminous film is known from WO 2021 / 023743 A1. Such luminous films are used, for example, indoors. The luminous film known from WO 2021 / 023743 A1 comprises several light-emitting diodes, a carrier layer, and a light-guiding layer made of micro-optical structures that allow the multidirectional light emitted by the light-emitting diodes to be redirected into a common emission direction of the luminous film. This enables uniform illumination of the luminous film surface with a small number of light-emitting diodes on the luminous film. The emission direction can be orthogonal to the luminous film.
[0005] Especially when using luminous foils outdoors, viewers view the foil from different directions. For example, when used on buildings, the view is often from below at an angle. Light emitted horizontally or upwards is therefore wasted.
[0006] Object of the invention
[0007] It is an object of the invention to further improve the energy efficiency of luminous films.
[0008] Description of the invention
[0009] This object is achieved according to the invention by a luminous foil having the features specified in claim 1, a luminous arrangement according to claim 15 and an operating method according to claim 20.
[0010] Luminous film according to the invention
[0011] According to the invention, a luminescent film is provided. The luminescent film has a plurality of light-emitting diodes. Typically, the number of light-emitting diodes is at least 1,000, preferably at least 10,000, particularly preferably at least 100,000. The light-emitting diodes are arranged on a carrier layer, in particular attached directly to the carrier layer. For example, the light-emitting diodes can be glued or welded to the carrier layer. The carrier layer can be a film, in particular a black one, made of plastic or textile fabric, for example. The carrier layer can impart stability to the luminescent film and protect the light-emitting diodes from damage. The light-emitting diodes are typically electrically connected to one another by a conductor track layer. The conductor track layer can be provided on or in the carrier layer. The luminescent film further has at least one first micro-optical layer for deflecting the light emitted by the light-emitting diodes.According to the invention, a main radiation direction of the luminous film for the light-emitting diodes deviates from a surface normal of the luminous film in the area of the respective light-emitting diode. In other words, the micro-optical layer causes the main radiation direction to deviate from the surface normal when the luminous film is in operation (i.e. when the light-emitting diodes are switched on). The light is emitted in a directed manner. This allows the light emitted by the luminous film to be specifically directed to the position of a viewer or onto a surface to be illuminated. The proportion of emitted light that does not reach the intended target is reduced. With the luminous film according to the invention, on the one hand, the energy required to achieve a desired illuminance in the area to be illuminated is reduced. At the same time, the radiation of light in undesired directions is reduced, thus also reducing light pollution.
[0012] The main radiation direction describes the direction in which the light emitted by one of the LEDs reaches its maximum intensity. The deviation of the main radiation direction from the respective surface normal is preferably at least 15°, more preferably at least 30°, most preferably at least 45°. The surface normal runs perpendicular to the light-emitting surface of the luminous foil and generally through the respective LED. In the case of a flatly arranged luminous foil, the surface normal has the same direction for all LEDs. In the case of a curved luminous foil, the surface normals point in different directions for different LEDs.
[0013] In principle, the main radiation direction of all LEDs on the luminous film deviates from the respective surface normal. In special cases, the luminous film may have additional LEDs where the main radiation direction corresponds to the respective surface normal. The number of additional LEDs is generally less than 5%, preferably less than 2%, particularly preferably less than 1% of the total number of LEDs.
[0014] It is preferably provided that for the light-emitting diodes, in particular all light-emitting diodes except for some additional light-emitting diodes that may be present, the light emission range is at most 120°, preferably at most 90°, particularly preferably at most 60°, and most particularly preferably at most 45°. This further reduces light pollution during operation of the luminous foil.
[0015] In a preferred embodiment, the first micro-optical layer has a first micro-optical region with first micro-optical elements for each LED. The micro-optical regions for the individual LEDs can be spaced apart from one another or directly adjacent to one another. By providing a separate micro-optical region for each LED, the structure of the luminous film is simplified. Furthermore, the emission characteristics of the luminous film can be particularly advantageously controlled by adapting the optical properties to a position of the respective LED on the luminous film.
[0016] Preferably, at least one optical property of the first micro-optical elements changes across the respective first micro-optical region. The optical property can change continuously or steadily in a direction traversing the respective first micro-optical region. This allows for the fact that, depending on the position of the micro-optical element relative to the associated LED, a deflection of the light emitted multidirectionally by the respective LED is required to varying degrees in order to achieve the desired radiation characteristic of the luminous foil.
[0017] Particularly preferably, the first micro-optical elements each have a reflective layer, in particular wherein the reflective layers of the respective first micro-optical region enclose different angles with a light entry side of the first micro-optical layer in the respective first micro-optical region. Light from the LEDs striking the reflective layers is thus reflected in the desired direction. In a direction traversing the respective first micro-optical region, the angles of successive micro-optical elements can continuously increase. The light entry side typically runs parallel to a tangential plane to the luminescent film in the region of the respective micro-optical element. In other words, the surface normal is typically perpendicular to the light entry side.
[0018] The first micro-optical elements can each comprise a prism, particularly one with a triangular cross-sectional area. This can assist in deflecting the light emitted by the LEDs in the desired direction. Furthermore, such micro-optical elements can be manufactured cost-effectively.
[0019] Particularly preferably, the reflective layers are formed on a side surface of the respective prism. This further improves the effectiveness of the first micro-optical layer. Furthermore, the first micro-optical layer can be efficiently produced, for example, by vapor-depositing the reflective layer onto the respective side surfaces.
[0020] The first micro-optical layer can be formed from an embossed plastic film, particularly made of acrylic plastic. In particular, prismatic micro-optical elements can be embossed into the film. This can further simplify the production of the first micro-optical layer. The refractive index of the plastic film is typically greater than 1. Alternatively or additionally, microlenses could be glued onto a plastic film.
[0021] The first micro-optical elements can run parallel to one another in the respective first micro-optical regions. In other words, the micro-optical elements can be arranged in a lamella-like manner. This allows the first micro-optical layer to deflect the light emitted by the LEDs in a first plane that runs perpendicular to the direction of extension of the micro-optical regions. This is advantageous for the manufacturability and design of the luminous foil.
[0022] In an advantageous embodiment, the luminous foil has a second micro-optical layer for deflecting the light emitted (during operation) by the LEDs, wherein the second micro-optical layer causes deflection in a different direction than the first micro-optical layer. This allows the radiation characteristics of the luminous foil to be adapted to complex operating conditions, particularly when the luminous foil is curved in multiple directions. The second micro-optical layer can, in principle, be constructed in the same way as the first micro-optical layer; in this respect, reference is made to the preceding description.
[0023] In particular, the second micro-optical layer can have a second micro-optical region with second micro-optical elements for each light-emitting diode, preferably wherein at least one optical property of the second micro-optical elements changes, in particular continuously, across the respective second micro-optical region. The second micro-optical elements are generally aligned to deflect the light in a different plane than the first micro-optical elements.
[0024] Preferably, the second micro-optical layer is arranged between the light-emitting diodes and the first micro-optical layer. The second micro-optical regions of the second micro-optical layer can then be smaller than the first micro-optical regions of the first micro-optical layer. It can be provided that the second micro-optical regions are spaced apart from one another, while the first micro-optical regions are directly adjacent to one another.
[0025] The second micro-optical elements can each have a reflective layer. Preferably, the second micro-optical elements each have a prism, in particular with a triangular cross-sectional area, particularly preferably with the reflective layers formed on a side surface of the respective prism. The second micro-optical layer can be formed with an embossed plastic film, in particular made of acrylic plastic. In particular, prismatic micro-optical elements can be embossed into the film. The refractive index of the plastic film is typically greater than 1.
[0026] The second micro-optical elements can run parallel to one another in the respective second micro-optical regions. In other words, the second micro-optical elements can be arranged in a lamella-like manner. Typically, the second micro-optical elements extend perpendicular to the first micro-optical elements, even if the first micro-optical elements run parallel to one another.
[0027] The first and / or second micro-optical regions can be individually adapted for the individual LEDs or groups of LEDs. In other words, the micro-optical regions can differ from one another in different sections of the luminescent film.
[0028] In a preferred embodiment, the luminous foil has a diffuser layer. This allows the light emitted by the LEDs to be homogenized. The number of LEDs required for uniform illumination can be reduced. The diffuser layer is typically arranged between the LEDs and the first or second micro-optical layer.
[0029] Preferably, a separate diffuser element is provided for each LED. This simplifies the construction of the diffuser layer or the luminous foil as a whole. The diffuser elements can have a diameter that is smaller than the distance between adjacent LEDs, in particular less than two-thirds of the distance between adjacent LEDs.
[0030] The spacing between adjacent LEDs can be at least 1 mm, preferably at least 2 mm, particularly preferably at least 5 mm, and / or at most 100 mm, preferably at most 60 mm, particularly preferably at most 40 mm. The diameter of the diffuser elements can be at least 0.5 mm, preferably at least 1 mm, particularly preferably at least 2.5 mm, and / or at most 50 mm, preferably at most 30 mm, particularly preferably at most 20 mm. In particular, the diameter of the diffuser elements can correspond to half the spacing between the LEDs.
[0031] The layers (i.e., at least the carrier layer and the first micro-optical layer, as well as, if applicable, the second micro-optical layer, the diffuser layer, and / or the conductor layer) of the luminous film can be bonded together using an optically transparent adhesive. This enables efficient production of the luminous film. At the same time, the brightness of the luminous film is not noticeably affected by the transparency of the adhesive.
[0032] The individual LEDs of the luminous film can generally be controlled independently of one another. The luminous film can therefore be used for a wide variety of applications, for example, to display images, symbols, or videos. The luminous film can have a control device for controlling the individual LEDs independently of one another. The control device can be attached to the carrier layer, for example, as an integrated circuit. The control device can be connected to the LEDs via control lines, in particular via a conductor layer.
[0033] A preferred embodiment is one in which the thickness of the luminous film is at least 0.1 mm, preferably at least 0.2 mm, particularly preferably at least 0.3 mm, and / or at most 40 mm, preferably at most 30 mm, particularly preferably at most 20 mm. The thickness of the luminous film is generally measured in the direction of the surface normal.
[0034] Particularly preferred is an embodiment in which the film is designed to be bendable, in particular rollable. In particular, the bending radius and / or rolling radius is at least 1 cm, preferably at least 2 cm, and / or at most 10 cm, preferably at most 5 cm. The term "light-emitting diode" is used here to represent all light-emitting diodes, diode modules, diode components (dies), etc. Those skilled in the art are aware that the use of more specialized light-emitting diode components can lead to modifications of the luminous film according to the invention. Likewise, the term "light-emitting diode" refers to all colors of light-emitting diodes as well as combined colors in light-emitting diode components.
[0035] Lighting arrangement according to the invention
[0036] The present invention also includes a lighting arrangement comprising a support structure and a luminous foil according to the invention, as described above, which is held on the support structure. The luminous foil can be brought into an operating position via the support structure and secured in this operating position. The previously described advantageous effects of the luminous foil according to the invention become particularly apparent in this case.
[0037] The support structure can be part of a motor vehicle, in particular a body of the motor vehicle. The invention therefore also relates to the use of a luminous film according to the invention described above on a motor vehicle and to a motor vehicle having a luminous film according to the invention described above. In particular, the luminous film can be attached to the outside of the motor vehicle. The directional characteristic of the luminous film makes it possible, for example, to visually highlight planned driving maneuvers such as parking maneuvers on a roadway. Optical communication with pedestrians detected by a driver assistance system can also take place, for example by projecting light signals into the pedestrian's expected path.
[0038] The support structure can be part of a building. The invention therefore also relates to the use of a luminous film according to the invention described above on a building and to a building with a luminous film according to the invention described above. In particular, the luminous film can be attached to a facade of a building. In this application, the advantages of the luminous film with regard to reduced energy consumption and reduced light pollution become particularly apparent.
[0039] Preferably, the main radiation direction of the luminous foil for the LEDs is directed downwards. This allows the emitted light to be directed specifically at an area in front of a building or a motor vehicle.
[0040] The light emission area can extend up to a maximum of 10° above the horizontal, preferably up to a maximum of the horizontal, particularly preferably up to a maximum of 30° below the horizontal, and most particularly preferably up to a maximum of 45° below the horizontal. Particularly when the luminous foil is used on a building, this can effectively reduce light pollution and significantly lower energy consumption. Compared to a conventional luminous foil with a beam angle of approximately 180°, the luminous intensity is doubled with radiation up to a maximum of the horizontal, using the same amount of energy; conversely, the energy consumption can be halved for the same luminous intensity in the area to be illuminated.With radiation up to a maximum of 45° below the horizontal, the luminous intensity quadruples with the same energy consumption compared to a conventional luminous foil with a radiation angle of approximately 180°; conversely, for the same luminous intensity in the area to be illuminated, the energy requirement can be reduced to a quarter.
[0041] The luminous foil can be curved in at least one direction, preferably curved in two directions, and held on the support structure. The at least one curvature gives the luminous foil a three-dimensional shape. In particular, a facade with the luminous foil can be curved in one or more directions. Likewise, a body part of a motor vehicle with the luminous foil can be curved in one or more directions. Concave and convex curvatures can alternate in one or two directions. The luminous foil can, for example, have a wave-like shape. Typically, the micro-optical regions for the LEDs are individually adapted to their position on the curved luminous foil or support structure. This makes it possible to achieve uniform illumination despite the differently oriented surface normals.
[0042] To create a three-dimensional shape for the luminous film, the luminous film can be cut, and the sections separated by cutting lines can be folded out. Alternatively, it is conceivable to obtain a three-dimensional shape for the luminous film by deep drawing, particularly vacuum deep drawing. If the support structure is an injection-molded part, the luminous film can be inserted into an injection mold and back-injected, creating the lighting arrangement as a composite component with the support structure and the luminous film.
[0043] Operating method according to the invention
[0044] Also within the scope of the present invention is an operating method for a luminous film according to the invention as described above or a luminous arrangement according to the invention as described above. The operating method provides that the light-emitting diodes in different sections of the luminous film are operated with different luminosity, so that a uniform illuminance is achieved within an illuminated area. This operating method is particularly useful with a curved luminous film and / or a non-planar surface to be illuminated. In particular, due to the curvature of the luminous film and possibly different radiation angles of the luminous film for the individual light-emitting diodes, the light from different numbers of light-emitting diodes can overlap in different sectors of the illuminated area. If all light-emitting diodes had a uniform luminosity, this would result in inhomogeneous illumination with brightness peaks.The invention avoids the energy expenditure required for excessive illumination of individual sectors of the illuminated area. Further features and advantages of the invention will become apparent from the description, the claims, and the drawings. According to the invention, the features mentioned above and those further detailed may each be used individually or in combination in any convenient way. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention.
[0045] Detailed description of the invention and drawing
[0046] The invention is illustrated in the drawing and described using exemplary embodiments. They show:
[0047] Fig. 1 shows a section of a luminous film according to the invention with several light-emitting diodes, for emitting light through a diffuser layer and a first micro-optical layer, wherein first micro-optical regions are spaced apart from one another, in a schematic plan view;
[0048] Fig. 2 shows a schematic cross section through an inventive
[0049] Luminous film with several light-emitting diodes, for emitting light through a diffuser layer and a first micro-optical layer, wherein first micro-optical regions are directly adjacent to one another;
[0050] Fig. 3 shows a lighting arrangement according to the invention with a luminous foil according to the invention held on a building, the radiation area of which extends from below to just above the horizontal, in a schematic side view;
[0051] Fig. 4 shows a schematic side view of a lighting arrangement according to the invention with a luminous foil according to the invention mounted on a building, the radiation range of which extends from below to 45° below the horizontal; Fig. 5 shows a section of a luminous foil according to the invention with several light-emitting diodes for emitting light through a diffuser layer and a first and second micro-optical layer, with only one of the many light-emitting diodes being shown;
[0052] Fig. 6 is a schematic vertical section through the luminous foil of Figure 6;
[0053] Fig. 7 is a schematic horizontal section through the luminous foil of Figure 6;
[0054] Fig. 8 is a schematic representation of individual parts of the luminous foil of Figure 6;
[0055] Fig. 9 shows a lighting arrangement according to the invention with a curved luminous foil according to the invention, wherein light-emitting diodes in different areas of the luminous foil shine with different brightness in order to uniformly illuminate an illuminated area, in a schematic plan view;
[0056] Fig. 10 shows a lighting arrangement according to the invention with two curved luminous foils according to the invention, which are held on a body of a motor vehicle, in a schematic side view.
[0057] Figure 1 shows a luminous film 10 according to the invention in a partial view. The luminous film 10 has a plurality of light-emitting diodes 12, four of which are located in the section shown. The light-emitting diodes 12 are held on a carrier layer 14. The carrier layer 14 can be formed by a plastic sheet. A conductor track layer (not shown in detail), which can also be held on the carrier layer 14, serves to supply power to the light-emitting diodes. Light emitted by the light-emitting diodes 12 is guided through a diffuser layer 16 with individual diffuser elements 18 and a first micro-optical layer 20 with first micro-optical regions 22. Each individual light-emitting diode 12 is assigned a diffuser element 18 and a first micro-optical region 22. In the embodiment shown in Figure 1, the first micro-optical regions 22 are spaced apart from one another.
[0058] The LEDs 12 are arranged in a matrix-like manner in rows and columns. The spacing between adjacent LEDs 12 in the rows or columns can be, for example, 16 mm. The diameter of the diffuser elements can be, for example, 8 mm.
[0059] Figure 2 shows a sectional view of a luminous foil 10 similar to Figure 1. Unlike Figure 1, in the embodiment shown in Figure 2, the first micro-optical regions 22 of adjacent light-emitting diodes 12 are directly adjacent to one another. Otherwise, the luminous foils 10 shown in Figures 1 and 2 are identical in their construction.
[0060] The diffuser elements 18 are bonded to the carrier layer 14 via a first adhesive layer 24 made of optically transparent adhesive, for example, acrylic adhesive. The LEDs 12 are embedded in the first adhesive layer 24. The LEDs 12 can also be bonded to the carrier layer 14 in a manner not shown in detail.
[0061] The first micro-optical layer 20 is bonded to the diffuser layer 16 or the diffuser elements 18 via a second adhesive layer 26 made of optically transparent adhesive, for example, acrylic adhesive. It is understood that the first and second adhesive layers 24, 26 could also merge into one another and completely envelop the diffuser elements 18 (not shown in detail).
[0062] The light emitted by the LEDs 12 passes through the first adhesive layer 24 and strikes the diffuser elements 18; compare the beam paths indicated by arrows in the lower part of Figure 2 (refraction effects are not shown in the beam paths for the sake of clarity). The diffuser elements 18 scatter the light emitted by the LEDs 12.
[0063] The scattered light passes through the second adhesive layer 26 and strikes the first micro-optical regions 22 of the first micro-optical layer 20 at a light entry side 28. The first micro-optical layer deflects the light so that for each light-emitting diode 12, a main emission direction 30 deviates from an associated surface normal 32. Deflected light rays do not run strictly parallel to one another; rather, the intensity maximum of the light emitted by a first micro-optical region 22 is located in the main emission direction 30. In the illustrated embodiment, the first micro-optical layer 20 deflects the light by approximately 60° (by 60° downwards with the orientation of the luminous foil 10 shown in Figure 2). The surface normals 32 are each aligned perpendicular to the light entry side 28 of the first micro-optical regions 22 of the respective light-emitting diodes 12.
[0064] The first micro-optical layer 20 has a plurality of first micro-optical elements 34 in each first micro-optical region 22. The first micro-optical elements 34 are prismatic in this case with a triangular cross-sectional area. In particular, the first micro-optical elements 34 extend parallel to one another within a respective first micro-optical region 22 (see also Figure 1). In the planar state of the luminous foil 10, the first micro-optical elements 34 of different first micro-optical regions 22 also extend parallel to one another.
[0065] The first micro-optical layer 20 is formed in this case by a plastic film, for example, made of acrylic plastic. The prismatic first micro-optical elements 34 can be embossed into the plastic film.
[0066] The first micro-optical elements 34 each have a reflective layer 36. The reflective layers 36 are each formed on a side surface of the prismatic first micro-optical elements 34. For example, the reflective layers 36 can be vapor-deposited onto the respective side surfaces. In the boundary region between adjacent first micro-optical regions 22, the reflective layers 36 can extend into the second adhesive layer 26 in order to prevent light from one light-emitting diode 12 from passing into the first micro-optical region 22 assigned to another light-emitting diode 12.
[0067] In order to deflect the light striking the light entry side 28 from different directions into the main emission direction 30 across the entire first micro-optical regions 22, an optical property of the first micro-optical elements 34 changes within the respective first micro-optical regions 22. Here, the individual reflection layers 36 each enclose a different angle 38 with the light entry side 28. In the cross-section shown perpendicular to the direction of extension of the first micro-optical elements 34, the included angle 38 changes continuously; in Figure 2, the angle 38 increases from bottom to top.
[0068] Figure 3 shows a lighting arrangement 40 with a luminous foil 10, such as that shown in Figure 1 or 2. The luminous foil 10 is held on a support structure 42. The support structure 42 here is a facade 44 of a building 46.
[0069] By appropriately adjusting the optical properties of the first micro-optical layer 20, the luminous foil 10 of the luminous arrangement 40 of Figure 3 is configured such that light is emitted into a region 48 that extends almost vertically downwards and upwards to just above the horizontal. Virtually no light is emitted beyond these limits. The main radiation direction 30 is directed downwards and can be inclined relative to the horizontal by, for example, approximately 30°. Since in the luminous arrangement 40 of Figure 3, a portion of the light is also emitted in an approximately horizontal direction, another building 50 opposite lies within the radiation region 48 of the luminous foil 10.
[0070] Figure 4 shows a similar lighting arrangement 40 to Figure 3. The optical properties of the first micro-optical layer 20 of the luminous foil 10 are selected here such that the radiation area 48 extends from almost vertically downward to approximately 45° below the horizontal. The main radiation pattern 30 in Figure 4 extends downward at an angle of approximately 60° to the horizontal. In this embodiment, the opposite building 50 is not located within the radiation area 48 of the luminous foil 10.
[0071] Figure 5 shows a section of a luminous foil 10 with many light-emitting diodes 12 held on a carrier layer 14, in which, in addition to a diffuser layer 16 and a first micro-optical layer 20, a second micro-optical layer 52 is additionally provided (see also Figures 6, 7, and 8). The second micro-optical layer 52 deflects the light emitted by the light-emitting diodes 12 in a different direction than the first micro-optical layer 20. Here, the first and second micro-optical layers 20, 52 act in mutually perpendicular directions. Accordingly, in second micro-optical regions 54, second micro-optical elements 56 are aligned perpendicular to first micro-optical elements 34 in first micro-optical regions 22.
[0072] In the present case, the second micro-optical layer 52 is constructed in the same way as the first micro-optical layer 20. In particular, the second micro-optical layer 52 can be formed by an (acrylic) plastic film into which the second micro-optical elements 56 are embossed as prisms with a triangular cross-sectional area. Side surfaces of the second micro-optical elements 56 are each provided with a reflective layer 58 (see in particular Figure 7). Different angles are enclosed between the reflective layers 58 and a light entry side 60 of the second micro-optical layer 52 within a respective second micro-optical region 54.
[0073] The diffuser layer 16 with the diffuser elements 18 is here—as with the luminous foils 10 shown in Figure 1 or 2—connected to the carrier layer 14 via a first adhesive layer 24 made of optically transparent adhesive. The second micro-optical layer 52 can be bonded directly to the diffuser layer 16 or the diffuser elements 18. Alternatively, the diffuser layer 16 and the second micro-optical layer 52 could be spaced apart from one another by an optically transparent adhesive layer of finite extension (not shown in detail). The first micro-optical layer 20 is connected to the second micro-optical layer 52 via a second optically transparent adhesive layer 26. Here, too, the adhesive layers for 24, 26 could merge into one another (not shown in detail). The adhesive layers 24, 26 are not shown in Figure 8.
[0074] Light emitted multidirectionally by one of the light-emitting diodes 12 (in Figures 5 and 8, the light-emitting diode 12 radiates out of the plane of the drawing toward the viewer) first strikes the associated diffuser element 18 of the diffuser layer 16 and is scattered thereby. The light is then deflected by the second micro-optical layer 52, specifically to the right in Figure 7, out of the plane of the drawing in Figure 6, and to the right in Figure 8. The light deflected in this way strikes the first micro-optical layer 20 and is deflected therein in a further direction, specifically downward in Figure 6, out of the plane of the drawing in Figure 7, and downward in Figure 8.
[0075] Figure 9 shows a lighting arrangement 40 in which a luminous foil 10, as shown, for example, in Figures 5 to 8, is held on a curved facade 44 of a building 46. A radiation area 48 of the luminous foil 10 may encompass another building 50 located opposite, so that an area 62 on its facade is illuminated. In order to set up the radiation area 48 as desired with a curved arrangement of the luminous foil 10, the optical properties, in particular those of the second micro-optical layer 52, differ depending on the position on the luminous foil 10. The optical properties of the first micro-optical layer 20 can also differ depending on the position on the luminous foil 10, in particular if the luminous foil is curved in a second direction, for example on a spherical facade. The first micro-optical layer can deflect the light from the luminous foil 10 downwards (into the plane of the drawing).
[0076] Due to the curved arrangement of the luminous foil 10, different radiation angles are set up for the individual LEDs 12; this is indicated in Figure 9 by beam paths for LEDs arranged laterally on the outside of the luminous foil 10. The main radiation directions 30 of the LEDs 12 each deviate from the corresponding surface normal 32. Furthermore, the light from a varying number of LEDs 12 overlaps on the illuminated surface 62 depending on the position. In order to achieve uniform illuminance across the surface 62, the LEDs 12 of the luminous foil 10 are therefore operated with different luminosities depending on their position. This is indicated in Figure 9 by the variable thickness in the illustration of the luminous foil 10. It is understood that the actual luminous foil 10 generally has a uniform thickness.
[0077] Figure 10 shows a lighting arrangement 40 with two luminous foils 10, for example as shown in Figures 5 to 8 or in Figure 1 or Figure 2, which are attached to a motor vehicle 64. A holding structure 42 is formed on a body 66 of the motor vehicle 64 for each of the luminous foils 10. The luminous foils 10 are each curved in at least one direction. In the illustrated embodiment, the luminous foil 10 at the rear of the motor vehicle 64 has a concave curvature (in the lower region) and a convex curvature (in the upper region) in the side view.
[0078] The luminous foils 10 can be covered by cover elements (not shown in detail). The cover elements can be transparent entirely or at least in the area of the LEDs. Alternatively, the cover elements can have recesses for the passage of the light emitted by the LEDs and deflected by the micro-optical layers 20 and 52, respectively.
[0079] A control device 68 serves to independently control the individual LEDs 12 of the luminous foils 10. The control device 68 can be configured to communicate with a vehicle control system 70 or integrated into the vehicle control system 70. The vehicle control system 70 can be configured to perform driving maneuvers semi-automatically or automatically.
[0080] The main radiation directions 30 of the LEDs 10 are directed downwards. Depending on the position of the LED 10 on the respective luminous foil 10, the main radiation directions 30 deviate to varying degrees from a respective surface normal 32.
[0081] In summary, the invention relates to a luminous foil 10 with a plurality of light-emitting diodes 12. The luminous foil 10 has micro-optical elements 34, 56 arranged in at least one layer 20, 52. A separate micro-optical region 22, 54 with associated micro-optical elements 34, 56 can be provided for each light-emitting diode 12. The micro-optical elements 34, 56 can have different optical properties within the respective region 22, 54 depending on their position. The micro-optical regions 22, 54 can be structurally identical, but can differ in their optical properties depending on their location on the luminous foil 10. Light emitted by the light-emitting diodes 12 is deflected by the micro-optical elements 34, 56, so that for each light-emitting diode 12 a main radiation direction 30 deviates from a surface normal 32 of the light-emitting film 10 in the region of the respective light-emitting diode 12.The targeted deflection of the emitted light enables operation of the luminous foil 10 with low energy consumption. List of reference symbols.
[0082] Luminous film 10
[0083] LEDs 12
[0084] Carrier layer 14
[0085] Diffuser layer 16
[0086] Diffuser elements 18 first micro-optical layer 20 first micro-optical regions 22 first adhesive layer 24 second adhesive layer 26
[0087] Light entry side 28
[0088] Main radiation direction 30
[0089] Surface normal 32 first micro-optical elements 34
[0090] Reflective layer 36
[0091] Angle 38
[0092] Lighting arrangement 40
[0093] Support structure 42
[0094] Facade 44
[0095] Building 46
[0096] Area 48 of light emission (emission area) further building 50 second micro-optical layer 52 second micro-optical areas 54 second micro-optical elements 56
[0097] Reflective layer 58
[0098] Light entry side 60
[0099] Illuminated area 62
[0100] Motor vehicle 64
[0101] Body 66
[0102] Control device 68
[0103] Vehicle control 70
Claims
Claims: A light-emitting film (10) with a plurality of light-emitting diodes (12) arranged on a carrier layer (14) and with at least one first micro-optical layer (20) for deflecting the light emitted by the light-emitting diodes (12), characterized in that a main emission direction (30) of the light-emitting film (10) for the light-emitting diodes (12) deviates from a surface normal (32) of the light-emitting film (10) in the region of the respective light-emitting diode (12). Light-emitting film (10) according to claim 1, characterized in that for the light-emitting diodes (12) a region (48) of light emission is at most 120°, preferably at most 90°, particularly preferably at most 60°, most preferably at most 45°.A light-emitting film (10) according to one of the preceding claims, characterized in that the first micro-optical layer (20) has a first micro-optical area (22) with first micro-optical elements (34) for each light-emitting diode (12), preferably wherein at least one optical property of the first micro-optical elements (34) changes across the respective first micro-optical area (22), in particular continuously. A light-emitting film (10) according to claim 3, characterized in that the first micro-optical elements (34) each have a reflective layer (36), in particular wherein the reflective layers (36) of the respective first micro-optical area (22) form different angles (38) with a light-entry side (28) of the first micro-optical layer (20).
5. Luminous film (10) according to claim 3 or 4, characterized in that the first micro-optical elements (34) each comprise a prism, in particular with a triangular cross-sectional area.
6. Luminous film (10) according to claims 4 and 5, characterized in that the reflective layers (36) are formed on a side surface of the respective prism.
7. Luminous film (10) according to one of claims 3 to 6, characterized in that the first micro-optical layer (20) is formed with an embossed plastic film.
8. Luminous film (10) according to one of claims 3 to 7, characterized in that the first micro-optical elements (34) in the respective first micro-optical areas (22) run parallel to each other.
9. Light-emitting film (10) according to one of the preceding claims, characterized in that the light-emitting film (10) has a second micro-optical layer (52) for deflecting the light emitted by the light-emitting diodes (12), wherein the second micro-optical layer (52) causes a deflection in a different direction than the first micro-optical layer (20).
10. Light-emitting film (10) according to claim 9, characterized in that the second micro-optical layer (52) has a second micro-optical area (54) with second micro-optical elements (56) for each light-emitting diode (12), preferably wherein at least one optical property of the second micro-optical elements (56) changes across the respective second micro-optical area (54), in particular continuously. A light-emitting film (10) according to claim 10, characterized in that the second micro-optical elements (54) each have a reflective layer (58), preferably wherein the second micro-optical elements (54) each have a prism, in particular with a triangular cross-sectional area, and especially preferably wherein the reflective layers (58) are formed on a side face of the respective prism. A light-emitting film (10) according to any one of the preceding claims, characterized in that the light-emitting film (10) has a diffuser layer (16), preferably wherein a separate diffuser element (18) is provided for each light-emitting diode (12). A light-emitting film (10) according to any one of the preceding claims, characterized in that the layers (14, 16, 20, 52) of the light-emitting film (10) are bonded together by an optically transparent adhesive.Light-emitting film (10) according to one of the preceding claims, characterized in that the light-emitting film (10) has a control device (68) for controlling the individual light-emitting diodes (12) independently of one another. Light-emitting arrangement (40) with a holding structure (42) and a light-emitting film (10) according to one of the preceding claims, which is held on the holding structure (42). Light-emitting arrangement (40) according to claim 15, characterized in that the holding structure (42) is part of a building (46). Light-emitting arrangement (40) according to claim 15, characterized in that the holding structure (42) is part of a motor vehicle (64), in particular a body (66) of the motor vehicle (64). A lighting arrangement (40) according to any one of claims 15 to 17, characterized in that the main emission direction (30) of the light-emitting film (10) for the light-emitting diodes (12) is directed downwards, in particular wherein a region (48) of the light emission extends to a maximum of 10° above the horizontal, preferably to a maximum of the horizontal, more preferably to a maximum of 30° below the horizontal, and most preferably to a maximum of 45° below the horizontal. A lighting arrangement (40) according to any one of claims 15 to 18, characterized in that the light-emitting film (10) is curved in at least one direction, preferably curved in two directions, and is held on the holding structure (42).Operating method for a light-emitting film (10) according to one of claims 1 to 14 or a light-emitting arrangement (40) according to one of claims 15 to 19, wherein the light-emitting diodes (12) in different sections of the light-emitting film (10) are operated with different luminous intensity, so that a uniform illuminance is achieved within an illuminated area (62).