Optical fiber element and method for manufacturing such an optical fiber element

Abstract

This disclosure relates to a light guide element (1) for a lighting element, comprising a light-guiding material (2) and a reflective film (3) provided with a microstructured surface (4), wherein the reflective film (3) and the light-guiding material (2) are joined by film injection molding and the microstructured surface (4) faces the light-guiding material (2). This disclosure further relates to a method for manufacturing a light guide element (1) and a lighting element comprising such a light guide element (1).

Description

The invention relates to a light guide element for a lighting element. Furthermore, the invention relates to a method for manufacturing such a light guide element and to a lighting element comprising such a light guide element. Prior art technology includes optical fiber elements comprising a reflective film and a light-guiding material. Conventional systems often require multiple assembly steps to combine reflective components and light-guiding materials, resulting in longer production times and higher energy consumption. Furthermore, integrating three-dimensional structures into such systems frequently leads to higher tooling costs and an increased risk of damage to the tools used in the manufacturing process. Disadvantages of the prior art include inefficient assembly processes, energy-intensive manufacturing steps, suboptimal light output due to reflective material properties, and challenges in implementing three-dimensional designs while maintaining high light quality. These problems increase manufacturing costs and limit design freedom. One objective of the present disclosure is to provide a light guide element that allows for efficient manufacturing, reduces the complexity of assembly, and ensures high light quality. This objective is achieved by a light guide element, a method for manufacturing a light guide element, and a lighting element, as disclosed herein. Preferred or advantageous embodiments can be derived from the description and the drawings. The present disclosure relates to a light guide element for a lighting element, comprising a light-guiding material and a reflective film provided with a microstructured surface, wherein the reflective film and the light-guiding material are joined by film injection molding (IMD), with the microstructured surface facing the light-guiding material. A significant advantage of this configuration is that the embossing of the reflective film reduces tooling costs and minimizes the risk of damage to the tool insert, as high-precision laser structuring is not required. Furthermore, the film injection molding process eliminates an assembly step, thereby reducing assembly time and energy consumption. Finally, the combination of the light-guiding material and the reflective film ensures improved light guidance and high optical quality. The injection molding (IMD) process ensures a permanent bond, while the three-dimensional shaping of the light-guiding material enables versatile design applications. Furthermore, IMD allows for the integration of complex geometries without additional assembly steps. After the IMD process, the light-guiding material forms the functional light guide. Advantageously, the microstructured surface of the light-emitting surface of the light-conducting material, particularly its upper surface, is positioned opposite the reflective film and is located on its back side, specifically its lower surface. This design contributes to energy efficiency and increases tool life by reducing manufacturing costs and the risk of tool damage. This configuration ensures precise alignment and efficient light deflection, resulting in increased light quality suitable for applications such as vehicles, household appliances and consumer electronics. A "lighting element" is a device or assembly that emits light and often includes a light guide element to increase brightness and light distribution. The term "light guide element" describes a component that efficiently directs and distributes light within a lighting system, thus ensuring uniform illumination. A "light-guiding material" is a transparent or translucent material designed to efficiently channel and distribute light, minimize losses, and optimize illumination. The light-guiding material is three-dimensionally shaped. After the film injection molding process, the light-guiding material forms the light guide of the light guide element. Reflective films are thin layers of material with reflective properties that redirect light, prevent dispersion, and improve light efficiency within the system. The reflective film described here is made of an energy-efficient material that minimizes light loss. The term "microstructured surface" describes a finely textured or patterned surface that influences the direction, scattering, or reflection of light to achieve specific optical effects. The microstructured surface is created on the reflective film through thermal or mechanical processes. It is located on the side of the reflective film facing the light-conducting material and is positioned opposite the light-emitting surface of the light-conducting material. Microstructured surfaces are optimized for applications in high-quality displays with 3D construction. Injection molding (IMD) is a manufacturing process in which a decorative or functional film, such as the reflective film described here, is placed in a mold and bonded to a material, especially the light-guiding material, during the molding process. “Facing” means that the microstructured surface is positioned or oriented towards the light-guiding material and the light-emitting surface of the light-guiding material, in particular the upper surface of the light-guiding material, to ensure correct alignment for functionality. The advantage lies in the fact that the microstructured surface is embossed into the reflective film, which simplifies the manufacturing process and reduces tooling costs while maintaining a high degree of design flexibility. It also ensures precise light scattering properties. Preferably, the reflective film comprises at least one side wall that is arranged substantially perpendicular to the reflective film to deflect light into a visible range and improve light confinement. The side wall covers an edge surface of the light-guiding material, thereby improving light confinement and reducing scattering. This configuration improves light confinement and reduces scattering. This feature also increases light confinement within the light guide element, thus increasing efficiency. According to one specific embodiment, the side walls of the reflective film are evenly distributed around all edge surfaces of the light-guiding material, thereby ensuring uniform light reflection. In one embodiment, the reflective film comprises a plurality of sidewalls that laterally surround the light-guiding material, thus ensuring optimal light deflection and improved structural integrity. The sidewalls enclose all circumferential edges of the light-guiding material, forming a trough-like structure that enhances light reflection. This further improves light guidance and light output. Another subject of the present disclosure is a method for manufacturing a light guide element, comprising the steps of providing a reflective film having a microstructured surface, providing a light-guiding material, and bonding the light-guiding material to the reflective film by film back injection molding, wherein the microstructured surface faces the light-guiding material. The reflective film and the light-guiding material are bonded together in a single injection molding process, which ensures precise alignment and reduces assembly complexity. A preferred embodiment of the method involves embossing the microstructured surface onto the reflective film before the film back-injection bond is created between the light-guiding material and the reflective film. This process ensures high-quality microstructuring at reduced costs. Another subject of the present disclosure is a lighting element comprising a light guide element described herein. The invention is particularly useful for displays that utilize optical fiber technology, for example, in automotive displays, household appliances, and consumer electronics. It is especially advantageous in applications requiring 3D-shaped optical fibers, as it offers improved optical efficiency and design flexibility. Further details are explained with reference to the drawing below. The drawing shows a schematic cross-section of a light guide element according to one embodiment. The light guide element 1 for a lighting element, not shown here, comprises a light-guiding material 2 and a reflective film 3 with a microstructured surface 4. The reflective film 3 is firmly bonded to the light-guiding material 2 by means of in-mold decoration (IMD), wherein the microstructured surface 4 faces the light-guiding material 2, in particular an upper surface 9 of the light-guiding material 2, wherein the upper surface 9 is the light-emitting surface of the light-guiding material 2. The reflective film 3 comprises several side walls 5, 6 that laterally surround the light-guiding material 2. For clarity, only two of the side walls 5, 6 are shown. In this case, the side walls 5, 6 are arranged perpendicular to the rest of the reflective film 3, which is located on the underside 10 of the light-guiding material 2, and contribute to directing the light into visible areas. The side walls 5, 6 come into contact with the outer edges 7, 8 of the light-guiding material 2. The light-guiding material 2 is formed into a three-dimensional shape during the manufacturing process, which allows for optimal adaptation to various applications. In this embodiment, the light-guiding material 2 has a rectangular cross-sectional shape. In a method according to the invention for producing a light guide element 1, a reflective film 3 and a light-conducting material 2 are provided, wherein the reflective film 3 has a microstructured surface 4. The light-conducting material 2 is bonded to the reflective film 3 by means of film injection molding, wherein the microstructured surface 4 is embossed onto the reflective film 3 before the film injection molding bond is created between the light-conducting material 2 and the reflective film 3. After the IMD process, the microstructured surface 4 faces the light-conducting material 2, more precisely the upper surface 9. Reference sign 1 Light guide element 2 Light-guiding material 3 Reflective film 4 Microstructured surface 5 Side wall 6 Side wall 7 Edge surface 8 Edge surface 9 Top surface 10 Bottom

Claims

Light guide element (1) for a lighting element, comprising a light-guiding material (2), a reflective film (3) provided with a microstructured surface (4), wherein the reflective film (3) and the light-guiding material (2) are joined by film injection molding, wherein the microstructured surface (4) faces the light-guiding material (2). Light guide element (1) according to claim 1, characterized in that the microstructured surface (4) is embossed onto the reflective film (3). Light guide element (1) according to claim 1 or 2, characterized in that the reflective film (3) comprises at least one side wall (5, 6) which is arranged substantially perpendicular to the reflective film (3). Light guide element (1) according to claim 3, characterized in that side walls (5, 6) of the reflective film (3) are distributed uniformly around all edge surfaces (7, 8) of the light-guiding material (2). Light guide element (1) according to claim 3, characterized in that the reflective film (3) comprises a plurality of side walls (5, 6) which laterally surround the light-guiding material (2). Method for manufacturing a light guide element (1) comprising the following steps:- providing a reflective film (3) having a microstructured surface (4);- providing a light-guiding material (2);- bonding the light-guiding material (2) to the reflective film (3) by film back injection, wherein the microstructured surface (4) is facing the light-guiding material (2). Method according to claim 6, characterized in that the microstructured surface (4) is embossed onto the reflective film (3) before the film back injection bond is created between the light-guiding material (2) and the reflective film (3). Lighting element comprising a light guide element (1) according to any one of claims 1 to 5.

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