LUMINOUS FILM WITH MICRO-OPTICAL STRUCTURE

Description

Background of the invention

[0001] The invention relates to a multi-layer luminous foil with several light-emitting diodes, a conductor layer for electrically connecting the light-emitting diodes and a carrier layer as is sufficiently known from the prior art.

[0002] Luminous films are known, for example, from US 2018 / 0245754 A1, WO 2015 / 176972 A1, WO 2011 / 114263 A1, WO 2014 / 155237 A1, WO 2016 / 131819 A1, FR 2 992 401 A1 and US 2017 / 0254518 A1.

[0003] Conventional luminous films are manufactured by coating a flexible substrate with light-emitting diodes. The uniform illumination of the films depends largely on the number of LEDs on the substrate and their spacing. The measure of the coverage of the substrate with LEDs is the fill factor. Achieving the highest possible uniformity in light emission requires either the highest possible fill factor, i.e., a very large number of LEDs and very close spacing between the LEDs, or additional diffusely translucent layers that scatter the light entering the diffuser.

[0004] While increasing the number of LEDs increases the electrical power consumption of the luminous film and thus the thermal load, additional diffuser layers lead to a significant increase in film thickness and a reduction in luminosity. Therefore, both solutions are usually used in combination, which, however, does not produce satisfactory results.

[0005] Both common solutions lead to increased manufacturing costs and increased power consumption of the film. Another disadvantage of conventional luminous films with a large number of LEDs is the associated cooling measures for the luminous film, which in turn reduces the film's formability. The adverse effect of reduced film formability is also even more pronounced in conjunction with thick diffuser layers, which can be up to seven centimeters thick, and can lead to the film becoming completely stiff. Diffuser layers are therefore sometimes applied only after the luminous films have been positioned. Object of the invention

[0006] It is an object of the invention to provide a luminous film which, with a low fill factor, i.e. a low density of light-emitting diodes and a low film thickness, enables good deformability and, at the same time, low-loss homogeneous illumination of the luminous film. Description of the invention

[0007] This object is achieved according to the invention by a luminous film according to claim 1. The dependent claims give preferred embodiments.

[0008] The micro-optical layer according to the invention comprises micro-optical components that have lens, prism, polarizer, filter, phase plate, mirror, aperture, grating structures, fibers, and / or light guides for directing the light introduced into the micro-optical layer. The micro-optical components obtain their micro-optical function by shaping and / or changing the refractive index of an optically uniform starting material, in particular an acrylic film.

[0009] Shaping can be achieved using conventional processes such as melting, grinding, drawing, etching, pressing, and / or polishing. This list is not intended to be exhaustive with regard to the processes mentioned.

[0010] The micro-optical layer uses micro-optical components, particularly by arranging a large number of micro-optical structures, to direct the light introduced into the micro-optical layer along defined optical paths. An optical path determines the exit point and exit angle of a light beam depending on the entry point and the entry angle. The difference from a conventional diffuser lies in the inhomogeneous beam guidance through the optical layer, whereas a diffuser is characterized by a homogeneous beam path.

[0011] For this purpose, the micro-optical layer has a structured surface with repeating micro-optical regions. The micro-optical regions serve to redirect the light introduced into the micro-optical layer at different angles. Starting from an optical center located directly above a light-emitting diode, the micro-optical regions are predominantly rotationally symmetrical, particularly circular and / or elliptical. The micro-optical regions have a larger surface area than the light-emitting diodes.

[0012] The dimensions of the micro-optical regions are adapted to the LED spacing and can vary in the direction of extension of the micro-optical layer. In particular, the direction-dependent dimensions of the micro-optical regions correspond at least to the LED spacing in this direction of extension of the micro-optical layer. This ensures that the light emitted by the LEDs is reliably redirected at least up to half the LED spacing.

[0013] The light emitted by the LEDs is used particularly effectively because the adjacent micro-optical regions overlap. This allows light to be used at very large beam angles.

[0014] The micro-optical layer can be made of glass, quartz glass, polymers, especially acrylic, and / or silicon. The use of crystals is also conceivable. The use of polymers can be particularly advantageous in reducing the costs of manufacturing the micro-optical layer.

[0015] 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 will be aware that the use of more specialized light-emitting diode components may lead to modifications of the luminescent 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. Preferred embodiments and further developments

[0016] A preferred embodiment is one in which the film has a textile layer or a nonwoven layer on the light-emitting film surface. A textile layer or nonwoven layer enables particularly homogeneous illumination of the luminous film and also offers acoustic advantages.

[0017] A preferred embodiment provides for the textile layer or nonwoven layer to be formed by flocking the film. Flocking allows the textile layer or nonwoven layer to be produced particularly easily and cost-effectively during film production. It is also conceivable to apply the flocking at a later point in time after film production, for example, after film installation. This provides particularly good protection for the textile layer or nonwoven layer against damage.

[0018] In a particularly preferred embodiment, the flocking consists of a mixed granulate of a wide variety of granules and / or fibers. This advantageously allows for an irregular flocking pattern, which promotes particularly high sound absorption of the luminous film. Alternatively or additionally, the granulate can consist of translucent, particularly transparent, granules and / or fibers, which can also improve the illumination of the film.

[0019] Alternatively or in addition to a textile layer, a fleece and / or a fabric, a top layer, in particular a silicate plaster, liquid wallpaper, anti-bacterial and / or an anti-adherent layer can be provided.

[0020] Furthermore, an embodiment is preferred in which the first micro-optical layer predominantly, in particular completely, encloses the light-emitting diodes. This allows the light emitted by the light-emitting diodes to be directed particularly effectively through the micro-optical layer, reducing light loss and further increasing the uniformity of the film's illumination.

[0021] The micro-optical layer is preferably formed in the form of a stamped and / or pressed layer. Alternatively or additionally, the micro-optical layer can be formed in one piece. The micro-optical components can be formed in the form of a planar, integrated optic of the micro-optical layer.

[0022] In a preferred embodiment, the film has a mirror layer located behind the LEDs in the direction of radiation of the film. Such a mirror layer reflects light emitted against the direction of radiation of the film, ensuring even more effective and lower-loss utilization of the light emitted by the LEDs.

[0023] In a particularly preferred embodiment, the mirror layer and the carrier layer form a single layer. This enables particularly effective and cost-effective production of the film, since the mirror layer is already created during the production of the carrier layer. This also allows the mirror layer to be made particularly thin.

[0024] When using a mirror layer, the micro-optical layer can be arranged particularly effectively in the radiation direction of the luminescent film behind the LEDs and in front of the mirror layer. This allows the optical path through the micro-optical layer to be extended or the micro-optical layer to be made particularly thin. In this case, the light emitted by the LEDs against the radiation direction of the luminescent film is first directed through the micro-optical layer against the radiation direction of the luminescent film to the mirror layer. The mirror layer reflects the incoming light in the direction of the radiation direction of the luminescent film, whereby the light is directed once more through the micro-optical layer and finally exits at the surface of the luminescent film. This further increases the effectiveness of the light guidance by the micro-optical layer and the proportion of light used.

[0025] A preferred embodiment is one in which the film has an additional micro-optical layer with micro-optical components, with the light-emitting diodes arranged between the two micro-optical layers. This allows for particularly cost-effective light guidance, and the manufacturing effort can be reduced to the arrangement of the layers.

[0026] Particularly preferred is an embodiment in which the carrier layer consists of a film, a nonwoven, and / or a woven fabric, in particular a textile, particularly preferably paper. This offers the advantage of a broad range of applications, since the carrier layer can be adapted to the prevailing conditions at the site of use. In a particular development, the carrier layer can be translucent, in particular completely transparent. This allows the luminous effect of the film to be implemented on both sides.

[0027] Furthermore, an embodiment is preferred in which the conductor track layer is partially translucent, in particular completely translucent. The translucency of the conductor track layer allows it to be arranged in front of the light-emitting diodes in the radiation direction of the luminous film without the conductor tracks interfering with the luminous effect of the film.

[0028] In a preferred embodiment, the conductor layer may consist of copper, electrically conductive ink, indium zinc oxide and / or silver oxide.

[0029] A further preferred embodiment is one in which the textile layer or nonwoven layer is unidirectionally translucent, particularly aligned in the radiation direction of the film. This allows the luminous effect of the luminous film to be particularly uniform.

[0030] Particularly preferred is an embodiment in which the textile layer or the nonwoven layer is at least partially acoustically hard and / or soft. This allows the luminous film to be used in areas with acoustic requirements or to improve the acoustic conditions. Depending on the requirements, the textile layer can therefore be designed to be sound-absorbing and / or sound-reflecting.

[0031] It is intended that the LEDs have a distance between 8 millimeters and 100 millimeters.

[0032] In a particular embodiment, the fill factor of the luminous film with homogeneous illumination is between 5 and 50%, in particular between 7 and 25%, particularly preferably between 9 and 15%.

[0033] A preferred embodiment is one in which the film thickness is 0.1 millimeters to 40 millimeters, in particular 0.2 millimeters to 30 millimeters, particularly preferably 0.3 millimeters to 20 millimeters. The thickness of the film refers to the predominant film thickness without taking into account an optional textile layer.

[0034] The film is designed to be rollable. The bending and / or rolling radius is between 1 centimeter and 10 centimeters, particularly preferably between 2 centimeters and 5 centimeters.

[0035] Furthermore, an embodiment is preferred in which the control of the LEDs is arranged on the film, in particular in the film, particularly preferably directly on the LEDs. A control arranged in this way simplifies the installation and delivery of the LED film and reduces the space required for attaching the LED film. Detailed description of the invention and drawing

[0036] Fig. 1shows a schematic view of a first embodiment of a non-claimed luminous foil; Fig. 2 shows a schematic view of a second embodiment of the luminous film according to the invention; Fig. 3 shows a schematic view of a third embodiment of a non-claimed luminous foil.

[0037] Fig. 1 shows the schematic side view of a first embodiment of a luminous foil 10 with several LEDs 12 (for reasons of clarity, only one LED has been given a reference symbol), a conductor layer 14, which electrically connects the light-emitting diodes 12, a carrier layer 16 and a micro-optical layer 18.

[0038] To clearly illustrate the effect of the micro-optical layer 18, the schematic diagram shows the luminous effect of the LEDs with and without the micro-optical layer 18. The two LEDs 12, arranged on the right side of the conductor track layer 14, have a scattering light pattern. Starting from the LEDs 12, the light is emitted multidirectionally with different intensities. In order to achieve the most homogeneous illumination of the luminous foil 10, the prior art therefore either adjusts the distance A the LEDs are reduced or a diffuser layer (not shown) is used to scatter the light.

[0039] On the left side of the schematic diagram, the light-emitting diodes 12 are provided with a micro-optical layer 18 in the direction of radiation RThe micro-optical layer 18 has micro-optical components through which the unidirectionally emitted light of the LEDs 12 is coupled into the micro-optical layer 18 and guided along optical paths 20 through the micro-optical layer 18. The formation of the micro-optical layer 18 according to Fig. 1 leads to a predominantly unidirectional radiation at the exit of the light from the micro-optical layer 18. With the same LED spacing A, a higher homogeneity of the illumination of the luminous film can thus be achieved.

[0040] In this embodiment, the LED spacing A also corresponds to the width of the micro-optical areas B. The micro-optical region B comprises the region of the micro-optical layer 18 in which incoming light is directed via the micro-optical structures to the light-emitting surface. Fig. 1 shows adjacent micro-optical areas B.

[0041] The embodiment according to Fig. 1 also has on the light-emitting film surface O a textile layer / fleece 22 The use of such a textile layer / nonwoven 22 further improves the homogeneity of the film's illumination by scattering the emitted light on the surface. Furthermore, the luminous film 10 can be designed with acoustic requirements in mind, which further increases the usability of the luminous film 12.

[0042] Furthermore, the embodiment comprises a control unit 24which is electrically connected to the conductor track structure 14 and serves to control the LEDs 12. The control unit 24 can be designed as a central control unit 24, as shown, or can be decentralized using a series of control units located near the LEDs. Alternatively or additionally, the control unit can be arranged on the film surface, in particular on the carrier layer (shown with dashed lines).

[0043] Fig. 2 shows a schematic representation of a second embodiment of the luminous foil 10 according to the invention. The luminous foil 10 has a mirror layer 26which is arranged behind the light-emitting diodes 12 opposite to the radiation direction R of the luminous foil 10. The micro-optical layer 18 is arranged between the light-emitting diodes 12 and the mirror layer 18. The light emitted by the light-emitting diodes 12 opposite to the radiation direction R of the luminous foil 10 is directed opposite to the radiation direction R by the micro-optical layer 18 and reflected by the mirror layer 26. The reflected light is deflected in the radiation direction R and directed in the radiation direction R by the micro-optical layer 18 to the emitting surface O. The light-emitting surface O is formed by a translucent, in particular transparent, conductor track layer 14, which is additionally flocked with a textile layer / nonwoven 22. In this case, with a similar thickness of the micro-optical layer as in embodiment 1 ( Fig. 1), the optical paths 20 which are greatly extended by the reflection at the mirror layer 26 (for reasons of clarity, only one optical path 20 has been provided with a reference symbol).

[0044] In addition, the schematic representation of the luminous foil 10 shows overlapping micro-optical regions B. By overlapping the micro-optical regions B, highly scattered emitted light—which under conventional circumstances counts as a loss—can still be directed particularly effectively to the light-emitting surface O. This effect is particularly pronounced when the light-emitting diodes 12 are enclosed by the micro-optical layer 18.

[0045] For illustration purposes, the diagram again shows the beam path under the influence of the micro-optical layer 18 (light-emitting diodes 12 on the left in the schematic representation) and without its influence (light-emitting diodes 12 on the right in the schematic representation).

[0046] Fig. 3shows a schematic representation of a third embodiment of the luminous film 10. The luminous film 10 has an additional micro-optical layer 18. The light-emitting diodes 12 and the conductor layer 14 are arranged between the two micro-optical layers 18. The conductor layer 14 is translucent, in particular transparent, so as not to interfere with the transmission. The arrangement of the two micro-optical layers 18 enables the formation of a wide micro-optical region B and, accordingly, a low density of light-emitting diodes 12—illustrated by the LED spacing A—while still providing homogeneous illumination of the luminous film 10.

[0047] From the representation of the luminous foil 10 in Fig. 3It is also evident that the light emitted by the light-emitting diodes 12 undergoes light guidance by the micro-optical structures of the micro-optical layers 18 both when emitted opposite to the emission direction R of the luminous foil and when emitted in the emission direction R of the luminous foil 10 or transversely thereto. List of reference symbols

[0048] 10Light-emitting film; 12Light-emitting diodes; 14Conductor layer; 16Carrier layer; 18Micro-optical layer; 20Optical paths; 22Textile layer / fleece; 24Control unit; 26Mirror layer; AA distance between the LEDs; B width of the micro-optical area; O light-emitting film surface; R radiation direction of the light-emitting film.

Claims

1. A multilayer luminous film (10) having a plurality of light-emitting diodes (12), a conductor layer (14) for the electrical connection of the light-emitting diodes (12) and a carrier layer (16), the luminous film (10) having a micro-optical layer (18) with micro-optical components for producing homogeneous illumination, the light-emitting diodes (12) having a spacing (A) of between 8 millimeters and 100 millimeters, the microoptical layer (18) having a structured surface having repeating microoptical regions (B), the microoptical regions (B) being predominantly rotationally symmetrical starting from an optical center, which lies precisely above a light-emitting diode (12), the microoptical regions (B) having a larger area than the light-emitting diodes (12), wherein the neighboring microoptical regions (B) overlap and wherein the luminous film (10) is designed to be rollable, the bending and / or rolling radius being between 1 cm and 10 cm.

2. The luminous film according to claim 1, characterized in that the luminous film (10) has a textile layer or a fleece layer (22) on the light-emitting film surface (O).

3. The luminous film according to claim 2, characterized in that the textile layer or the fleece layer (22) is formed by flocking the luminous film (10), in particular the light-emitting film surface (O).

4. The luminous film according to any of the preceding claims, characterized in that the first microoptical layer (18) predominantly, in particular completely, encloses the light-emitting diodes (12).

5. The luminous film according to any of the preceding claims, characterized in that the luminous film (10) has a mirror layer (26) that is located behind the light-emitting diodes (12) in the emission direction (R) of the luminous film (10).

6. The luminous film according to any of the preceding claims, characterized in that the mirror layer (26) and the carrier layer (16) form a common layer.

7. The luminous film according to any of the preceding claims, characterized in that the luminous film (10) has a further microoptical layer (18) having microoptical components, the light-emitting diodes (12) being arranged between the two microoptical layers (18).

8. The luminous film according to any of the preceding claims, characterized in that the carrier layer (16) consists of a film, a fleece and / or a woven fabric, in particular a textile, particularly preferably a paper.

9. The luminous film according to any of the preceding claims, characterized in that the conductor layer (14) is designed to be partially translucent, in particular completely translucent.

10. The luminous film according to any of the preceding claims, characterized in that the conductor layer (14) consists of copper, electrically conductive ink, indium zinc oxide and / or silver oxide.

11. The luminous film according to any of the preceding claims, characterized in that the textile layer or the fleece layer (22) is oriented to be unidirectionally translucent, in particular in the emission direction (R) of the luminous film (10).

12. The luminous film according to any of the preceding claims, characterized in that the textile layer or the fleece layer (22) is at least in part sonically hard and / or soft.

13. The luminous film according to any of the preceding claims, characterized in that the film thickness is 0.1 millimeters to 40 millimeters, in particular 0.2 millimeters to 30 millimeters, particularly preferably 0.3 millimeters to 20 millimeters.