Method for producing an illuminable assembly and illuminable assembly

Abstract

Method for producing an illuminable assembly (100), comprising the following steps: - providing a conductor layer comprising electronic components and a plurality of light emitting diodes (12) emitting light laterally, - Inserting the conductor layer into an injection mold, - forming a light guide (20) with a plurality of illuminable segments (22) by injection-molding an at least partially transparent, first plastic onto the conductor layer, wherein the first plastic is applied at least in sections to the conductor layer, so that the laterally light-emitting section (14) of the respective light-emitting diode (12) is surrounded by the first plastic, wherein the plurality of illuminable segments (22) extend at a distance from one another and are connected to one another via a common base (26), wherein the base (26) surrounds the laterally light-emitting sections (14) of the light-emitting diodes (12) that are assigned to the plurality of illuminable segments (22), - forming a light barrier (30) for the plurality of illuminable segments (22) by overmolding the plurality of segments (22) with a second plastic, wherein the second plastic surrounds the rear side of the respective light-emitting diode (12) and the plurality of illuminable segments (22) at least in sections, wherein a plastic with a thermal conductivity of at least 5 W / mK is used as the second plastic.

Description

[0001] A method for manufacturing an illuminable assembly and an illuminable assembly are described. The illuminable assembly can be used for direct or indirect lighting.

[0002] Such an assembly can be used, for example, in the field of motor vehicles for interior lighting and / or for illuminating components in the interior of a vehicle. State of the art

[0003] To illuminate instruments, control panels, and trim panels, fiber optics are often used, into which light is introduced via an LED. These lighting arrangements often feature fiber optics surrounded by a light barrier to ensure the best possible illumination and to prevent the light introduced into a fiber optic cable from being influenced by light from other fiber optics or lighting devices. The required light source is usually mounted on a circuit board, which must be connected to the fiber optic cable or an illuminable surface.

[0004] Several process and assembly steps are required to produce an appropriately illuminated assembly.

[0005] First, a printed circuit board must be prepared. This preparation also includes the assembly, arrangement, and fastening of the electronic components and conductor tracks arranged on it. In parallel manufacturing steps, the light guide(s) and the light barrier are manufactured separately. The individual components are then assembled. For this purpose, the components have mounting sections. The mounting sections enlarge the components and must be manufactured within tight tolerances so that the components can be fastened together.

[0006] WO 2009 / 075924 A1 discloses an illuminable component with a light-emitting diode housed in a transparent connecting element. Due to its special design, the connecting element can be connected to a separately manufactured light guide. This allows the light guide to be illuminated. In a subsequent processing step, a separately manufactured light barrier can be applied to the non-illuminable side of the light guide, and the assembly can be housed within a housing.

[0007] The known designs of illuminable assemblies consist of individual components that are manufactured in separate production steps and must be attached to each other. These assemblies are therefore often large and require additional installation space.

[0008] Often, additional elements, such as a connector for connecting a circuit board to a control bus, must be attached and connected to the assembly.

[0009] Therefore, multiple manufacturing and assembly processes (e.g., soldering, gluing, welding, etc.) are required to create an assembly, increasing production costs and the time required for the assembly. Furthermore, the assemblies are large, so the limited installation space available, especially in vehicles, is either insufficient or the arrangements take up too much space.

[0010] DE 100 21 100 A1 describes a device for illuminating a display with a light guide and a plurality of light sources.

[0011] EP 2 322 962 A1 describes an arrangement comprising a light guide, a light source, a diffuser, each manufactured by injection molding, as well as a light source and housing which is injection molded onto the light guide.

[0012] WO 2009 / 043 849 A1 describes a module with an injection-molded housing with a thermal conductivity of 1 to 10 W / mK used in an arrangement. Task

[0013] The object is therefore to provide a method for producing an illuminable assembly and an illuminable assembly which can be produced easily and quickly, has small dimensions and enables reliable operation, whereby illumination can be achieved in various designs and the essential components are protected.

[0014] The process should also enable the production of an illuminable assembly, which reduces the requirements for the manufacturing process compared to known processes. Solution

[0015] The object described above is achieved by a method for producing an illuminable assembly according to claim 1.

[0016] The method enables the production of an illuminable assembly, whereby the electronic components, such as the conductor layer with conductor tracks, a contact point for a connector, at least one laterally emitting light-emitting diode (so-called side LED) and electronic control and regulation elements, are connected to a connector, a light guide and the light barrier in an injection molding process.

[0017] The contact point serves to accommodate a plug, whereby the contact point is applied to the conductor layer. The plug can be inserted into the mold of an injection molding tool during the injection molding process and connected to the contact point. The connection can also be made before insertion into the mold. The components are then surrounded at least in sections by the first plastic and firmly connected to the conductor layer. The conductor layer can comprise a flexible film provided with the electronic components. Alternatively, a circuit board with, for example, integrated conductor tracks can be provided as the conductor layer. The electronic control and regulating elements include resistors, diodes, capacitive elements and control units, etc.

[0018] The light guide is formed such that the first plastic surrounds the laterally light-emitting section of the at least one LED and extends from this section. The course of the light guide and / or the multiple segments can be straight. The course of the light guide and / or the segments can also be curved or bent, with the course changing in at least one direction.

[0019] The provision of so-called "side LEDs," which emit light from the side, allows for a reduction in the height of the assembly, thus saving installation space. Furthermore, a reduction or minimization of assembly steps is achieved, since the electronic components are connected to the connector, the light barrier, and the light guide during the injection molding process.

[0020] This process eliminates the need to adhere to tight manufacturing tolerances because the components are molded onto or against each other. This results in less scrap and eliminates the need for post-processing. The assembly height can also be very low because the components are directly connected to each other. Additional fastening sections are not required.

[0021] Both static and dynamic lighting can be realized with the module, whereby the lighting depends on the control of the necessary electronics, which are applied to the conductor layer.

[0022] In particular, area illumination can be achieved via the assembly, with the light guide segment being designed accordingly for this purpose. The segment can be funnel-shaped, with the segment widening starting from the LED. In further embodiments, the segment can already have the final width of the illuminable area starting from the at least one LED.

[0023] The height of the segment can also be kept very low by using "side LEDs," which allows for a very flat assembly design. Direct illumination can also be achieved through a flat light emission along the segment. Furthermore, indirect illumination is also possible through light extraction from the front of the segment. The light barrier surrounds the non-illuminated area of ​​the segment, preventing interference with neighboring segments or other components and protecting the surrounding segment itself. Furthermore, the light barrier serves as a reflection, allowing targeted illumination of the illuminable area. The injection-molded light barrier further reduces the required assembly steps.

[0024] For the first plastic, an at least partially transparent plastic is selected so that the segment can be illuminated. An opaque plastic is used for the second plastic. The first plastic and the second plastic can have different shrinkage properties (shrinkage), so that, for example, the first plastic contracts more strongly after cooling than the second plastic. This allows a distance to be achieved between the light barrier and at least one segment when the component has cooled down.

[0025] The second plastic can be colored to achieve better reflection of the light introduced into the light guide or segments.

[0026] The second plastic also exhibits high thermal conductivity. The first plastic, in contrast, does not exhibit high thermal conductivity. The second plastic surrounds the back of the LED, allowing the heat generated during operation of the LED to be dissipated through the light barrier. The illuminable area of ​​the segments or the light guide, in contrast, is not heated, so no heating of illuminable areas or surfaces occurs.

[0027] The second plastic can be applied to the conductor layer in such a way that a contact point and / or the electronic components (e.g., control and regulating elements) are surrounded by the second plastic. This allows the heat generated by the components on the conductor layer to be dissipated via the light barrier. Additionally, the components, such as the contact point and the electronic control and regulating elements, can be protected from external influences by the second plastic. The second plastic can thus serve as a protective layer for the components.

[0028] The method also involves forming multiple segments that are spaced apart from one another and connected by a common base. The base surrounds the laterally light-emitting portions of LEDs assigned to the segments. The base can be configured to serve as a common light guide for multiple LEDs. The separation between the individual segments is achieved by notches or incisions introduced or formed during the injection molding process. This prevents light introduced via the respective LEDs from reaching the neighboring segments.

[0029] The second plastic used is a plastic with a thermal conductivity of at least 5 W / mK.

[0030] In further embodiments, a thermoplastic injection molding material filled with BN particles can be used as the second plastic. Plastics and polymers are not thermally conductive themselves. Therefore, additives are required to provide thermal conductivity. The thermal conductivity of the second plastic depends on the amount and type of additives used for the polymer or injection molding material. Thermal conductivities of several watts (>10, >100, etc.) can also be generated. The number of LEDs provided and the heat output of the LEDs must be taken into account. In further embodiments, where the light barrier is also intended to dissipate heat from the other electronic components on the conductive layer, their heat output must also be taken into account.

[0031] The conductor layer can be formed from a film, with at least one laterally emitting light-emitting diode, conductor tracks, a contact point, and electronic control and regulation elements applied to the film. Such flexible circuit boards formed from a film have a very low height and are particularly suitable for the creation of very flat lighting assemblies. After the light guide and the light barrier have been molded on and off, the flexible circuit board is encased in plastic. Flexible circuit boards can be easily deformed, allowing any desired structure to be achieved for the illuminable assembly.

[0032] In other designs, the light guide and light barrier are also flexible after cooling and can be deformed. This allows the assembly to be used on curved surfaces and always adapts to the desired surface shape. Furthermore, play can also be compensated for. Plastics for this purpose can be treated with additives to achieve the desired flexibility.

[0033] The second plastic is preferably an opaque plastic with a color. The plastic's light-absorbing properties can be adjusted to meet specific requirements by adding additives.

[0034] All current-carrying components of the assembly can be encased in the first plastic and / or the second plastic. Overmolding the electronic components can therefore provide a watertight structure, protecting the sensitive components.

[0035] Furthermore, the conductor layer can be completely surrounded by the first plastic or the second plastic to provide heat dissipation via the light barrier for the electronic components via the second plastic. The first plastic is applied to the conductor layer in such a way that the light emitted by the LEDs reaches the light guide directly.

[0036] The above-mentioned object is also achieved by an illuminable assembly according to patent claim 8.

[0037] The assembly is suitable, for example, for symbol illumination on motor vehicle instruments (e.g., lighting devices, air conditioning, and other switches). The assembly can also be used to illuminate surfaces in a vehicle. The surfaces can be illuminated directly via the segments or via surfaces in front of the segments. This allows for both direct and indirect illumination. Indirect illumination can also be achieved by coupling light out from at least one end face of the segments.

[0038] Furthermore, both dynamic and static lighting are possible. In an assembly with multiple segments, the individual segments can be controlled separately by their assigned LEDs. This allows the LEDs to emit different colors without affecting each other. Furthermore, the brightness of the emitted light can be generated independently for each segment. The light barrier surrounds the respective segments so that only the illuminated area is exposed.

[0039] In further embodiments, flat sections can be provided over the segments, each of which can be illuminated by at least one associated light-emitting diode. A further layer or film comprising structures, symbols, or characters can be applied to these flat areas.

[0040] In further embodiments, the assembly has a plastic surface due to the first plastic and the second plastic and / or an underside of the conductive layer. Only a connector, which extends out of the plastic, forms an externally accessible, non-plastic component. Such an assembly can thus be designed to be watertight. The internal components are therefore protected. The use of thermally conductive polymers ensures good heat dissipation despite the encapsulated design, whereby no damage to the components, for example, LEDs, control logic, etc., can occur.

[0041] Further advantages, features and design options emerge from the following description of figures of non-limiting embodiments. Brief description of the drawings

[0042] In the drawings shows: Fig. 1 a perspective view of an illuminable assembly with a circuit board, a light guide and a light barrier; Fig. 2 a schematic representation of the circuit board of the assembly of Fig. 1; Fig. 3 a schematic representation of a light guide applied to the circuit board; Fig. 4 a schematic representation of the light barrier of the assembly of Fig. 1; Fig. 5 a perspective view of the light bulkhead; Fig. 6 a schematic representation of the rear side of the light barrier; Fig. 7 a schematic representation of the front of the assembly; and Fig. 8 a schematic sectional view through the assembly along the line AA of Fig. 7.

[0043] In the drawings, elements provided with the same reference numerals essentially correspond to one another unless otherwise stated. Furthermore, components that are not essential to understanding the technical teaching disclosed herein are omitted. Reference numerals will not be repeated for all elements already introduced and illustrated, provided that the elements themselves and their function have already been described or are known to a person skilled in the art. Detailed description of implementation examples

[0044] Fig. Figure 1 shows a perspective view of an illuminable assembly 100 comprising a circuit board 10, a light guide 20, and a light barrier 30. The assembly 100 is used to illuminate display areas in a vehicle, with multiple areas being independently illuminated. Each area is assigned to a segment 22, and the segments 22 of the light guide 20 are independently illuminated by controlling associated light-emitting diodes 12.

[0045] The light guide 20 has the illuminable segments 22, which have a base 26 (see Fig. 3) are interconnected. The light guide 20 is made of a transparent plastic and is therefore translucent. PMMI, PMMA, or PC, for example, can be used as the first plastic. The individual segments 22 are surrounded by a light barrier 30, with the segments 22 being separated from one another by the side walls 37 of the light barrier 30.

[0046] The light barrier 30 is made of an opaque plastic and exhibits thermally conductive properties. The second plastic is a polymer to which additives are added to create thermal conductivity. Such additives are known, for example, under the designations MWNT and BN. Aluminum oxide or iron (Fe) can also be added to achieve the desired conductivity. The second plastic has, for example, PA, PC, PBT, or PE-HD as its starting material.

[0047] To manufacture the assembly 100, a printed circuit board 10 is first provided. The printed circuit board 10 can be a flexible film on which electronic components are applied and which has integrated conductor tracks. The printed circuit board 10 can also be designed essentially as a non-flexible conductor track.

[0048] The circuit board 10 has various electronic components and conductor tracks required for illuminating and controlling the light-emitting diodes 12. The light-emitting diodes 12 are located in an edge section of the circuit board 10 and are so-called side LEDs. Side LEDs emit light laterally and are very low in height. Therefore, they are particularly suitable for forming very flat assemblies 100. The circuit board 10 has a single light-emitting diode 12 for each segment 22. The light-emitting diodes 12 are coupled to other electronic components and a control unit via conductor tracks (not shown). The control unit is connected to a connector via a contact point, wherein the connector is Fig. 2 is not shown. The connector, which is accessible from the outside of the module 100, can be used to connect the module 100 to a bus system of a vehicle via a control bus. The module 100 can be connected, for example, to the CAN bus of a vehicle. The LEDs 12 can be controlled via a central control unit of a vehicle or a decentralized control unit connected to the CAN bus.

[0049] The printed circuit board 10 has openings 16 and 18 at a lower edge section. The openings 18 are located at the lateral end areas and serve for later fastening the assembly 100 and the printed circuit board 10 to a supporting structure in the vehicle. The openings 16 serve to accommodate pins 34 of the light barrier 30.

[0050] To produce the assembly 100, the printed circuit board 10 is inserted into one half of an injection mold. Additionally or alternatively, the connector connected to the contact point can be inserted, for example, via a flexible cable. The connector is therefore movable relative to the printed circuit board 10. The injection mold has a receptacle for the connector, so that the position of the connector is predetermined for the finished assembly 100. The injection mold is then closed, and a first plastic is introduced. The first plastic serves to form the light guide 20. After the first plastic has been introduced, the light guide 20 is attached to the printed circuit board 10. Fig. 3 shows a schematic representation of a light guide 20 applied to the circuit board 10.

[0051] The light guide 20 has segments 22, each separated from one another by a gap 24. At the bottom, the segments 22 are connected to one another by a base 26. The base 26 is applied to the upper section of the circuit board 10 in an edge region and surrounds the laterally light-emitting section 14 of the LEDs 12. The light emitted by the LEDs 12 therefore passes through the section 14 directly into the light guide 20 and the segments 22. Since the LEDs 12 emit light in a straight line (in Fig. 3 upwards), there is no significant influence on the adjacent segments 22 via the base. For this purpose, the gap 24 extends as far downwards as possible.

[0052] The first plastic is sprayed onto the circuit board 10 and surrounds the sections 14 so that light can reach the illuminable segments 22 directly.

[0053] Unlike in Fig. 3, the segments 22 can also be curved. For example, the segments 22 can be curved upwards or downwards about an axis running orthogonal to the longitudinal axis of the circuit board 10. In further embodiments, the segments 22 can also additionally or alternatively have a curvature about an axis running parallel to the longitudinal direction of the circuit board 10. The segments 22 can also have a greater or shorter length than is schematically shown in the figures. The segments 22 can also differ from one another.

[0054] After the formation of the light guide 20 and cooling of the light guide 20, a second plastic is introduced into the mold of the injection mold to form the light barrier 30.

[0055] Fig. Figure 4 shows a schematic representation of the light barrier 30 of the assembly 100. The light barrier 30 has a plate 32 with openings 33 at its edges. The edges form connecting sections 36, via which the assembly 100 can be attached to a support structure. Screws, bolts, or pins can be inserted into the openings 33, connecting the assembly 100 to the support structure. The plate 32 also has pins 34. The pins 34 penetrate the openings 16 of the printed circuit board 10 and serve as a connection between the printed circuit board 10 and the light barrier 30.

[0056] The light barrier 30 has a closed rear side 31 (see Fig. 6) and side walls 37 and 39, which surround areas 38. The segments 22 are accommodated in the areas 38. The side walls 37 separate the individual segments 22 from each other and project beyond the segments 22 to the front, as shown in Fig. 1 shown.

[0057] Fig. Figure 5 shows a perspective view of the light barrier 30, illustrating the formation of the side walls 37 and the upper side wall 39 for forming the regions 38. The light barrier 30 is injection-molded onto the first plastic of the light guide 20 and the circuit board 10. The pins 34 penetrate the openings 16 and are connected to the circuit board 10 via them. In addition, there is a direct connection between the light barrier 30 and the circuit board 10 via the plate 32, which is applied to the circuit board 10.

[0058] Fig. Figure 6 shows a schematic representation of the rear side 31 of the light barrier 30 with the laterally projecting connecting sections 36, via which a connection to a supporting structure of a vehicle is established. The printed circuit board 10 has the openings 18, which, when the assembly 100 is assembled, are congruent with the openings 33. After inserting the fastening elements, the assembly 100 is then held by both the printed circuit board 10 and the light barrier 30.

[0059] Fig. Figure 7 shows a schematic representation of the front of the assembly 100.

[0060] Fig. Figure 8 shows a schematic sectional view through the assembly along the line AA of Fig. 7. The pins 34 penetrate the opening 16 of the circuit board 10 and thereby connect the circuit board 10 to the light barrier 30. Furthermore, an adhesive connection can exist between the surface of the circuit board 10 and the second plastic of the light barrier 30, so that the components are firmly connected to one another.

[0061] The light barrier 30 is not directly connected to the first plastic of the light guide 20. The plastics used exhibit different shrinkage rates. The first plastic preferably exhibits greater shrinkage than the second plastic to prevent a connection.

[0062] The light barrier 30 serves to protect adjacent segments 22 from stray light and to reflect the light rays penetrating the segment 22. The second plastic is colored to reflect the light rays and for optimized illumination. Preferably, the surfaces of the light barrier 30 opposite the segments 22 are white. The second plastic also has thermally conductive properties, so that the heat generated by the light-emitting diodes 12 and other electronic components arranged on the circuit board 10 can be dissipated via the light barrier 30. For this purpose, the light-emitting diode 12 is surrounded in its lateral light-emitting section 14 by the first plastic of the segment 22 so that light is introduced directly into it, and on the rear side of the light-emitting diode 12 by the second plastic with the thermally conductive properties. The heat of the light-emitting diode 12 can therefore be dissipated.Furthermore, the heat of the other associated electronic components, which are arranged on the circuit board 10 and surrounded by the second, heat-conducting plastic, can also be dissipated.

[0063] The amount of Fig. The thickness of the arrangement shown in Figure 8 can be as small as a few millimeters, thus providing a very flat arrangement. Furthermore, the individual components are firmly connected to one another, thus providing an encapsulated version of an assembly 100, wherein the electronic components are protected from water and contamination. The flat design of the light barrier 30 enables very good heat dissipation and heat removal, particularly over the large area on the rear side 31.

[0064] The side walls 37 and 39 project beyond the areas 38 and in particular the segments 22 in order to achieve a partitioning of the individual illuminable areas with the segments 22.

[0065] The 100 module is suitable for a wide range of applications thanks to its encapsulated design and is protected against external interference. List of reference symbols 10 circuit board 12 LEDs Section 14 16 Opening 18 Opening 20 light guides 22 segments 24 gap 26 Base 30 light bulkhead 31 Back 32 plate 33 Opening 34 cones 36 connecting section 37 side wall 38 Area 39 Side wall 100 assembly

Claims

[1] A method for producing an illuminable assembly (100), comprising the following steps: - providing a conductor layer comprising electronic components and a plurality of light emitting diodes (12) emitting light laterally, - Inserting the conductor layer into an injection mold, - forming a light guide (20) with a plurality of illuminable segments (22) by injection-molding an at least partially transparent, first plastic onto the conductor layer, wherein the first plastic is applied at least in sections to the conductor layer, so that the laterally light-emitting section (14) of the respective light-emitting diode (12) is surrounded by the first plastic, wherein the plurality of illuminable segments (22) extend at a distance from one another and are connected to one another via a common base (26), wherein the base (26) surrounds the laterally light-emitting sections (14) of the light-emitting diodes (12) that are assigned to the plurality of illuminable segments (22), - forming a light barrier (30) for the plurality of illuminable segments (22) by overmolding the plurality of segments (22) with a second plastic, wherein the second plastic surrounds the rear side of the respective light-emitting diode (12) and the plurality of illuminable segments (22) at least in sections, wherein a plastic with a thermal conductivity of at least 5 W / mK is used as the second plastic. [2] Method according to claim 1, wherein the second plastic is applied to the conductor layer in such a way that a contact point and / or the electronic components are surrounded by the second plastic. [3] Method according to one of claims 1 or 2, wherein a thermoplastic injection molding material filled with BN particles is used as the second plastic. [4] Method according to one of claims 1 to 3, wherein the conductor layer is formed from a film, wherein the light-emitting diodes (12) emitting light laterally, conductor tracks, a contact point and electronic control and regulating elements are applied to the film. [5] Method according to one of claims 1 to 4, wherein an opaque plastic is used as the second plastic. [6] Method according to one of claims 1 to 5, wherein all current-carrying components of the assembly (100) are surrounded by the first plastic and / or the second plastic. [7] Method according to one of claims 1 to 6, wherein the conductor layer is completely surrounded by the first plastic and / or the second plastic. [8] Illuminable assembly, manufactured by a method according to one of claims 1 to 7, comprising - a conductor layer with several light-emitting diodes (12) emitting light laterally, conductor tracks, a contact point and electronic control and regulating elements, - a light guide (20) with a plurality of illuminable segments (22) made of a first plastic and arranged on the conductor layer, wherein the plurality of illuminable segments (22) are applied at least in sections to the conductor layer, so that the laterally light-emitting section (14) of the respective light-emitting diode (12) is surrounded by the first plastic, and the plurality of illuminable segments (22) extend from the respective light-emitting diode (12), wherein the plurality of illuminable segments (22) run at a distance from one another and are connected to one another via a common base (26), wherein the base (26) surrounds the laterally light-emitting sections (14) of the light-emitting diodes (12) that are assigned to the plurality of illuminable segments (22), and - a light barrier (30) for the plurality of illuminable segments (22), which consists of a second plastic and surrounds the rear side of the respective light-emitting diode (12) and the plurality of illuminable segments (22) at least in sections, wherein the second plastic is a plastic with a thermal conductivity of at least 5 W / mK.

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