Lighting unit with flexible surface lighting body and method for producing a lighting unit

Abstract

The invention relates to a lighting unit comprising a flexible surface lighting fixture and a control unit. The surface lighting fixture comprises a flat carrier material with a, in particular textile-based, flexible, flat circuit carrier, which is equipped on a front side with a plurality of lighting devices that are interconnected by electrical lines formed in or on the circuit carrier. The control unit comprises a housing arranged on an edge of the surface lighting fixture and mechanically connected to it. For connection to the control unit, the circuit carrier of the surface lighting fixture has at least one elongated flexible printed circuit board tongue with conductor tracks, which is guided into the control unit through a slot in a wall of the housing of the control unit.According to the invention, the housing comprises an inner wall on the inside of the slot, which defines a cavity with the wall of the housing having the slot, which cavity is open on one side towards an interior of the housing and forms a chicane through which the printed circuit board tongue is guided from outside the housing to inside the housing under at least one bend, in particular an S-shaped bend, wherein the cavity with the printed circuit board tongue guided through is filled with a sealing compound.

Description

[0001] The present invention relates to a lighting unit comprising a flexible surface lighting body and a control unit, as well as a method for manufacturing such a lighting unit.

[0002] The applicant, among others, distributes such area lighting fixtures, which are described, for example, in German patent DE 10 2014 206 882 B4. They are designed for various applications, such as area illumination in photography, film, and television production. Particularly in the latter fields, continuous illumination with high luminous intensities is required, which in most cases is achieved by systems consisting of spotlights, reflectors, and diffusers. To illuminate changing scenes, the lighting system components used must be flexibly combinable, positionable, and adjustable.

[0003] In DE 10 2014 206 882 B4, it is proposed to provide a flexible surface lighting body which has a plurality of light sources distributed over a surface on a flat carrier material, wherein a first layer is designed as a textile-based flexible flat circuit carrier which is fitted on a front side with the plurality of light sources which are interconnected by electrical lines formed in or on the circuit carrier.

[0004] In simple terms, such a surface lighting fixture is a self-illuminating sheet that is flexible, rollable, foldable, rotatable, and crushable, and which has a luminosity distributed across its surface sufficient, for example, to illuminate a scene or part of a scene. These "sheets" or flexible surface lighting fixtures can be manufactured in any size and are therefore easy to assemble. Because their flexibility and surface area are similar to those of familiar reflectors and diffusers, they are suitable for replacing the conventional combinations of spotlights, reflectors, and diffusers. They also require less light output, since their entire luminous intensity is available to illuminate a given scene and is not, as with conventional spotlight systems, only partially deflected and diffused towards the scene.This also leads to a reduction in the waste heat generated.

[0005] German patent application DE 10 2020 116 917 A1 addresses the problem in such a lighting unit that the connection between the control unit and the surface lighting element is subjected to mechanical stress during operation, which negatively affects the electrical connection between the surface lighting element and the control unit. To remedy this problem, it is proposed to provide the part of the control unit housing that accommodates an edge of the surface lighting element with a strain relief device. This device absorbs tensile stresses between the control unit housing and the surface lighting element, thus preventing them from affecting the electrical connections between the control unit and the surface lighting element.This makes the lighting unit mechanically very robust and suitable for use in illuminating tents, including makeshift tents in the military sector, in disaster relief or in mobile medical facilities, in police operations for illuminating accident sites, as well as for private use, and also for photographers who need mobile, area-wide lighting outside their studios that can be set up quickly.

[0006] Starting from this state of the art, it is an object of the present invention to make corresponding lighting units even more robust against external stresses.

[0007] This problem is solved by a lighting unit comprising a flexible surface lighting element and a control unit, wherein the surface lighting element comprises a planar carrier material with a, in particular textile-based, flexible planar circuit carrier, which is equipped on a front side with a plurality of light sources which are interconnected by electrical conductors formed in or on the circuit carrier, wherein the control unit is designed for supplying power and controlling the plurality of light sources and comprises a housing arranged at an edge of the surface lighting element and mechanically connected to it, with electrical and / or electronic components and conductors, wherein the circuit carrier of the surface lighting element has at least one elongated flexible circuit board tab with conductor tracks for connection to the control unit.which is led into the control unit through a slot in a wall of the housing of the control unit, wherein the lighting unit is further developed in that the housing comprises an inner wall on the inside of the slot, which defines a cavity with the wall of the housing having the slot, which is open on one side to an interior of the housing and forms a baffle through which the circuit board tongue is guided from outside the housing to inside the housing under at least one bend, in particular an S-shaped bend, wherein the cavity with the circuit board tongue passed through it is filled with a sealant.

[0008] In this way, the interior of the control unit housing is hermetically sealed and thus protected from the ingress of dust and moisture.

[0009] The flexible surface light source advantageously incorporates textile components and LED-carrying PCB carriers (PCB, Printed Circuit Board) that are contacted onto the embroidered conductive traces on the textile. For protection against environmental influences such as dust, but especially moisture, the surface light source can be fully laminated. The laminate can consist of several layers and be sandwiched around the surface light source. A water vapor barrier can be implemented on the outermost layer, i.e., on the light-emitting and light-facing sides. Below, above, and below the light source, a thermoplastic layer is placed, with the light source itself in the center. Both the vapor barrier and the thermoplastic layer can advantageously be very thin, for example, approximately 50 µm thick, transparent films that preferably do not distort the color gamut, do not generate heat, and are UV-stable, water vapor-tight, elastic, and mechanically robust.

[0010] The laminate can be produced, for example, through a thermal process under pressure at approximately 140 °C, depending on the material chosen. The material should be selected so that the LED assemblies of the surface-mounted light source are not exposed to excessive heat. The laminate preserves the textile-like characteristics of the surface-mounted light source. The vapor barrier can be, for example, an aliphatic polyurethane. The flexible circuit board tab is laminated to such an extent that the laminated portion extends into the housing of the control unit.

[0011] The housing can advantageously be made of solid aluminum, which can be anodized after milling for aesthetic reasons. Such anodizing should be considered when selecting the potting compound. The potting compound, which is filled into the designated cavities inside the housing, should also create a watertight seal at the transitions from the flexible circuit boards to the housing's interior, against the housing slots. An example of such a product is Sikaflex®, a relatively high-viscosity, one-component (1K) sealant. This polyurethane-based sealant is stable, tear-resistant, humidity-curing, easy to apply without bubbles, precise to work with, and, most importantly, adheres firmly to all materials suitable for this application (laminate, flexible circuit board, anodized aluminum housing).

[0012] Alternatively, the control unit housing can also be made from other metals such as stainless steel or titanium, or from carbon fiber composites. Aluminum, on the other hand, has the advantage of being lighter than stainless steel, cheaper to obtain than titanium, and easier and better to process than carbon fiber.

[0013] In the context of this disclosure, a printed circuit board tongue is understood to be a narrow, elongated section of a flexible printed circuit board on which one or more conductor tracks are arranged parallel to one another to enable a connection to electrical or electronic power supply and / or control elements. The conductor tracks can, for example, terminate at the end of the PCB tongue in solder pads, onto which the contacts of the supplying electrical or electronic components are soldered. Alternatively, the ends of the flexible conductor tracks can terminate, for example, in a ZIF connector (zero insertion force connector), which is located as a component on a main circuit board within a package. This offers the advantage of faster and more reliable contacting in the process.The ZIF connector is opened, the end contact surface of the flexible circuit board is inserted, and closing the ZIF connector clamps the end in place, ensuring electrical contact. Such a contact is reversible, reliable, and fast, but must be protected from mechanical stress and tensile forces.

[0014] Sealing cavities into which flexible printed circuit boards are inserted through a slot in the cavity wall is notoriously difficult. German patent DE 10 2020 116 917 A1 proposes a circumferential seal in the form of a neoprene and / or silicone gasket, which is sealed by crimping or screwing together housing halves. However, such crimped or screwed seals leave slight gaps at the edges of the inserted objects, such as a flat flexible printed circuit board, through which moisture can still enter the interior of the housing, for example, via capillary action.

[0015] Potting offers a higher level of sealing here, as the flexible circuit board is completely embedded and encased, and no capillaries remain open, unlike with a pressed or screwed-in circumferential neoprene or silicone gasket. Instead, a metallurgical bond forms between the sealant and the surface of the circuit board tongue as it cures. However, such a seal, especially with flat objects like the narrow and flat circuit board tongue, is mechanically susceptible to tensile stress on the circuit board tongue, which can be easily pulled out of the surrounding sealant with minimal force. Once the metallurgical bond between the surface of the circuit board tongue and the surrounding sealant is broken, a channel forms around the circuit board tongue, through which moisture, for example, can penetrate due to capillary action.

[0016] For this reason, the PCB tongue is embedded within the sealant with a bend. This bend, particularly the S-shaped bend, ensures that a tensile load from outside the housing onto the PCB tongue is not only transferred to the surrounding sealant via the bond, but is also absorbed directly by pressure on the sealant on the side of the bend opposite the direction of pull. At this point, the shear forces are lower or even non-existent, which, in the case of a linear design without a bend, would cause the bond between the sealant and the PCB tongue to fail. In this way, the curved shape of the PCB tongue within the sealant provides a degree of tensile relief, which also offers resilience against the bond between the sealant and the PCB tongue failing.

[0017] In the section of the printed circuit board (PCB) tongue that is surrounded by sealant, the PCB tongue can be bent, or even bent several times, for example in an S-shape or in the form of a wave. A deflection angle of 30° or more is preferred; deflection angles of 90° or more are also possible. The deflection angle indicates by how many degrees the further course of the PCB tongue has been deflected from a straight path. A deflection angle of 0° would mean no deflection or bending whatsoever.

[0018] The bending of the PCB tab within the sealant is forced by the baffle-like cavity formed by an inner wall directly behind the slot. This cavity opens towards the interior of the housing in a direction perpendicular to the direction in which the PCB tab is inserted through the slot. Thus, after passing through the slot, the PCB tab initially encounters the inner wall that defines the baffle cavity and must be bent to navigate around it. The cavity can also be filled with sealant through the same opening to the interior of the housing through which the PCB tab exits. The cavity has the further effect of providing a well-defined volume for filling with sealant, thereby protecting the rest of the housing's interior from the sealant.

[0019] Preferably, in the final state, the circuit board tongue has no contact with the wall of the control unit housing, but is completely surrounded by sealant in the area of ​​the cavity forming the baffle.

[0020] Rubber, silicone, or a plastic can preferably be used as a sealant. Various PU compounds are preferred. Based on the chemical results, two-component (2K) materials are well suited, as are two-phase processes in which all micro-spaces are filled or lined with a low-viscosity sealant, and then the larger volume of the respective cavity is filled with a sealant of higher viscosity.

[0021] The working time depends on the materials used and can, for example, be one hour, allowing the sealant to set slowly. The commercially available Sikaflex®, for instance, is well-suited and meets the physical requirements of the product and its individual components, and is easy to use. Its viscosity is approximately 20 mm² / s at 40 °C.

[0022] In one embodiment, the edge of the surface lighting element is sectionally enclosed in the housing of the control unit, the housing comprising a strain relief element that absorbs tensile stresses between the housing of the control unit on the one hand and the surface lighting element on the other, and keeps these stresses away from the passage of the circuit board tongue through the baffle, in particular from the electrical connections between the control unit and the surface lighting element. The strain relief element engages externally from the passage of the circuit board tongue through the slot into the housing and thus relieves stress on both the hermetic seal and the electrical contacts inside the housing of the control unit.

[0023] The strain relief device is designed in embodiments as a clamping device or as a series of two or more strain-relieving pins, which are guided in the surface lighting body by a series of eyelets designed to match the arrangement of the strain-relieving pins. In particular, the carrier material in the area of ​​the eyelets is reinforced, especially by a double layer of the flexible, flat circuit carrier. This can be a stable textile outer component, for example, a ripstop fabric and / or a hemmed binding. A previously described laminate preferably terminates internally before this area in the textile of the surface lighting body, and is therefore not die-cut, thus ensuring watertightness.In one embodiment, the eyelets can be designed as retaining washers, or include retaining washers, or be secured by retaining washers that prevent them from slipping back after being slid onto the pull-in pins. Within the scope of this disclosure, retaining washers are defined as rings with a star-shaped central opening. Such retaining washers, also called spring washers, spring rings, star-shaped flanges, or toothed washers, have essentially triangular bendable surfaces or teeth extending inwards from the edge. When such a retaining washer is placed onto a pull-in pin whose diameter is slightly larger than the innermost diameter of the retaining washer, the inwardly pointing teeth are bent upwards and act as barbs to prevent the retaining washer from being pushed back.Such a connection can hardly be undone without damage and therefore offers a high level of mechanical security against unintentional loosening.

[0024] In some cases, the control unit housing is composed of two or more parts. To ensure watertightness and moisture resistance, some embodiments provide that the two or more parts of the control unit housing are sealed watertight against each other by means of a sealant applied along their butt joints. This sealant can be the same as that used in the cavities forming the baffles, or other known sealants suitable for watertight sealing of butt joints. Additionally, the housing parts can be screwed together.

[0025] In embodiments, the surface lighting element has a flexible, planar cooling layer on the rear side of the circuit carrier, which is mechanically or materially connected to the circuit carrier, and / or a rain- and dirt-repellent layer, wherein, in particular, the cooling layer is shielded to the outside by the rain- and dirt-repellent layer or is designed as a rain- and dirt-repellent layer, and / or a diffusion layer, in particular a removable one, and / or a directional grid on the front side of the circuit carrier, and / or the circuit carrier is provided with a reflective surface, in particular an aluminum layer, below the light source. These various layers, of which one, several, or all may be present, serve to protect against environmental influences or to distribute the light. The diffusion layer, however, need not be removable.It can also be firmly attached to individual or all other textile components by a seam.

[0026] In embodiments, the circuit carrier with the light sources and the electrical conductors is coated with a waterproof coating, in particular silicone, a lacquer or a laminate, wherein the waterproof coating also covers the flexible circuit board tongue at least as far as the housing of the control unit.

[0027] In further embodiments, the control unit, particularly a waterproof one, comprises operating elements, especially a membrane keypad, and / or a wireless communication interface via which the control unit can be remotely operated by means of a remote control unit or a mobile device. Membrane keypads are waterproof and suitable for use in demanding environmental conditions.

[0028] In one embodiment, the membrane keypad features an elongated, flexible printed circuit board tongue with conductive traces for electronic connection to electrical or electronic components within the housing. This tongue is guided into the housing through a further slot in a wall of the housing and a cavity filled with a sealant, which forms a baffle for the printed circuit board tongue. The membrane keypad can thus be externally mounted or attached to the housing, with the routing and hermetic sealing of the electrical connection between the membrane keypad and the control electronics inside the control unit housing being achieved in the same or a similar manner as that of the surface lighting element.

[0029] In another embodiment, an opening with a pressure diaphragm is provided in a wall of the control unit housing. The pressure diaphragm is watertight and connected to the edge of the opening. It is designed to withstand a water column of up to 2 m. The pressure diaphragm extends the functionality of the lighting unit beyond water resistance to include applications at high altitudes, such as in aircraft, or underwater. For this purpose, a concentric hole, for example approximately 1 mm in diameter, can be provided in the wall of the housing, with a circumferential relief of approximately 1 mm, for example, at the location of the slot for the flexible circuit board of the surface lighting element. A pressure diaphragm that meets the desired performance criteria can then be self-adhesively applied to the outside of the housing.The adhesive preferably has the appropriate protection class for waterproofing. This allows the pressure to be equalized while simultaneously maintaining the waterproofing of all compartments of the control unit.

[0030] The problem underlying the invention is also solved by a method for manufacturing a lighting unit with a flexible surface lighting element and a control unit, in particular a lighting unit as previously described according to the present invention, in the following steps: Arranging the flexible area lighting body at the edge of a control unit housing, threading an elongated flexible circuit board tongue of the flexible area lighting body through a slot in a wall of the control unit housing and a baffle-forming cavity defined by an inner wall with the wall of the housing having the slot, and creating a hermetic seal by filling the baffle-forming cavity including the threaded circuit board tongue with a sealant.

[0031] Using the means described above, the method creates a hermetic and resistant penetration of the circuit board tongue into the housing of the control unit, thereby achieving the same features, properties and advantages as the lighting unit according to the invention.

[0032] In one embodiment of the method, after threading and before or after creating the hermetic seal, an electrical connection is established between one or more contact surfaces on the printed circuit board tongue and one or more electrical or electronic components in the housing of the control unit.

[0033] In embodiments, the flexible surface lighting element is connected to the housing after being arranged and before or after threading and before or after creating a hermetic seal, in particular by providing strain relief for the passage of the circuit board tongue through the hermetic seal.

[0034] In further embodiments, an operating element, in particular a membrane keypad, is attached to the housing of the control unit, wherein an elongated flexible circuit board tongue of the operating element is threaded into the housing through a slot and a cavity arranged directly inside the slot and designed as a baffle, and the passage is then hermetically sealed by potting the cavity forming the baffle with a sealant.

[0035] In some embodiments, some or all of the aforementioned process steps are carried out with the control unit housing at least partially open, which is closed after the hermetic connection(s) are completed. In such cases, two or more parts of the housing can preferably be sealed against each other before closing by means of a sealant applied along their butt joints. In this way, the watertightness is extended to all butt joints of the housing parts. The sealant can be the same as that used for the cavities forming the baffles, or another sealant suitable for sealing butt joints.

[0036] Further features of the invention will become apparent from the description of embodiments according to the invention, together with the claims and the accompanying drawings. Embodiments according to the invention may fulfill individual features or a combination of several features.

[0037] Within the scope of the invention, features marked with "in particular" or "preferably" are to be understood as optional features.

[0038] The invention is described below, without limiting the general concept, with reference to exemplary embodiments and the drawings, whereby for all details of the invention not explained in detail in the text, explicit reference is made to the drawings. The drawings show: Fig. 1 a schematic perspective view of a lighting unit, Fig. 2 a schematic perspective view of a lighting unit from the outside, Fig. 3 a schematic cross-sectional view of a lighting unit in its wrapped state, Fig. 4 a schematic representation of a layer structure of a surface lighting element, Fig. 5 a schematic detail view of another layer structure, Fig. 6 a schematic representation of the components of a control unit of a lighting unit, Fig. 7 a schematic exploded view of an embodiment of a lighting unit, Fig. 8 a schematic representation of an embodiment of a control unit with sectional views, Fig. 9 a schematic perspective view of the control unit and Fig. 10 another schematic perspective view of the control unit.

[0039] In the drawings, identical or similar elements and / or parts are provided with the same reference numbers, so that a re-presentation is omitted.

[0040] Fig. 1Figure 10 schematically depicts a lighting unit 10 in perspective, as known from the applicant's German patent application DE 10 2020 116 917 A1. The lighting unit 10 comprises a control unit 20, the housing 22 of which is shown in its open state, without the electronic components such as circuit boards, batteries, circuits, control electronics, etc., arranged therein. The housing 22 has three tensile grips 24 on one transverse side, which project from a lower surface of the housing 22, and onto which a surface lighting element 50 is attached. For this purpose, the surface lighting element 50 has three eyelets 54 on one of its edges, i.e., reinforced openings that ensure a strain-relieved fit of the surface lighting element 50 onto the tensile grips 24 in the housing 22. The surface lighting body 50 is flexible and has a flat design and features a light-active surface 56, which is surrounded by a border 52 that is not light-active or does not need to be light-active.

[0041] Instead of strain relief via the strain-receiving pins 24 and eyelets 54, a clamping device (not shown) can also be used, which grips and clamps the surface lighting body 50 along one of its edges 52, optionally with a rubberized or profiled surface. The clamping then takes place along the side that, in the exemplary embodiment of the Fig. 1 which has 54 eyelets.

[0042] At the in Fig. 2In the lighting unit shown, also known from DE 10 2020 116 917 A1, the housing 22 of the control unit 20 is closed. The surface lighting element 50 protrudes from the housing 22 and has approximately the same width as the housing 22, although it may optionally be wider or narrower. Electrical conductors 60 and LED light sources 58 are shown as examples in the illuminating area 56, which actually fill the entire illuminating area 56. It is indicated that the LEDs are each arranged on circuit boards 59, each of which is connected by two or more conductors 60 that serve as the power supply. Several different LEDs with different colors or color temperatures can also be used on each circuit board, which are individually controlled to adjust the color temperature of the overall lighting. Exemplary embodiments are not limited to the selection of LEDs as light sources.

[0043] The LED light sources 58 and electrical conductors 60 are mounted on a circuit carrier 80, which may have a textile base, for example, a textile fabric. Details are described in DE 10 2014 206 882 B4. The electrical conductors and the circuit boards 59 can be sewn to the textile fabric, resulting in a secure yet low-stress connection between the electrical components and the circuit carrier 80. The design of the connection between the electrical components and the textile circuit carrier 80 creates a structure that can be easily and repeatedly rolled and folded.

[0044] The edge of the surface lighting body 50 has a circumferential, stiffening frame 70 in an O-shape. This frame can be an inflatable tube filled with compressed air or another pressurizable hydraulic fluid. Once the tube is filled with compressed air or hydraulic fluid and pressurized, it expands to its maximum dimensions, thus stabilizing the surface lighting body 50. The tube can either be part of the surface lighting body 50 or attached to it circumferentially, for example, with a hook-and-loop fastener. Once the compressed air or hydraulic fluid is released, the surface lighting body 50, together with its stiffening frame 70, can be rolled up.

[0045] Fig. 3Figure 1 schematically shows a cross-sectional embodiment of a corresponding lighting unit 10 in its rolled-up state. The surface lighting body 50, with its integrated frame 70 and circuit carrier 80, is tightly wound around the housing 22 of the control unit 20 and secured at its end by a fixing element 65 to prevent it from unwinding on its own. In this example, the fixing element 65 is a snap fastener. However, it could also be a hook-and-loop fastener or a magnetic closure. In this state, the back of the surface lighting body 50 faces outwards and is optionally protected with a dirt- and rain-repellent material, thus protecting the sensitive electrical and electronic components inside from dirt and water.

[0046] Fig. 4Figure 1 represents a layered structure of an exemplary surface lighting body 50 according to DE 10 2020 116 917 A1. LED light sources 58 are arranged on the textile circuit carrier 80, with a reflective layer 90 applied to the areas between the LED light sources 58. Alternatively, a mechanical protective layer can be used instead of the reflective layer 90, for example, in the form of a plastic film that has mask-like cutouts at the locations of the LED light sources 58 and thus covers and electrically insulates the spaces between the LED light sources 58. This film can itself also be metallized and thus constitute a reflective layer 90.

[0047] On the back of the circuit carrier 80 is a cooling layer 82, designed to absorb heat from the LED light sources 58 and conduct it into the surface and to the back, thereby reducing the temperature of the LED light sources 58 themselves compared to a configuration without a cooling layer 82. On the back of the cooling layer 82 is a rain- and dirt-repellent layer 84, made, for example, of a ripstop fabric. The rain- and dirt-repellent layer 84 can be attached to the cooling layer 82 or can be connected to the other layers only at their edges, so that an air cushion can form between the cooling layer 82 and the rain- and dirt-repellent layer 84. On the front, a diffusion layer 86 made of a diffusion fabric can be arranged, which is or will be connected to the circuit carrier 80 at the edge 52 of the surface lighting body 50.

[0048] Fig. 5Figure 1 shows a section from another example according to DE 10 2020 116 917 A1, in which the circuit carrier 80 and the LED light source 58 are encased together in a waterproof coating 88, for example, a silicone coating. The coating 88 does not have to have the same thickness over its entire surface, as shown, but can also be thinner in the area between adjacent LED light sources 58. This illustration also shows a cross-section through an LED light source 58 with circuit boards 59 and electrical conductors 60, the cross-sectional direction being perpendicular to the longitudinal extent of the electrical conductors 60. The electrical conductors 60 can be sewn onto the circuit carrier 80, for example, if the carrier is a textile material. The two LEDs can have different color temperatures or colors. For example, one LED can produce a warm white, and the other a cool white.It may also include a third LED (not shown) that produces red light illumination, thus not disturbing the adaptation of the human eye to dark environments.

[0049] In Fig. 6 Figure 10, 2020 116 917 A1, schematically illustrates the electrical and electronic components in the control unit 20. A central component is a control electronics unit 34, which is connected to a rechargeable or non-rechargeable battery 30 and may optionally include charging electronics for a rechargeable battery 30. Furthermore, the control electronics unit 34 is connected to the LED light sources 58 via the electrical lines 60 and controls them. A membrane keypad 32 is provided as an example of a manual input interface, which is used to communicate to the control electronics unit 34 how the LED light sources 58 should be controlled.

[0050] Optionally, an electric pump 38 can be provided, which, upon input and control by the control electronics 34, inflates a U-shaped surrounding frame 72 to stabilize the shape of the surface lighting unit 50. Furthermore, a wireless communication interface 36 can be provided, which receives signals from a remote control unit 40, decodes them, and transmits them to the control electronics 34. In this way, the operation of the lighting unit 10 can be remotely controlled.

[0051] Other possible components include buttons, display elements, especially LEDs or screens, which must also be integrated into the housing surface in a water- and dirt-resistant manner.

[0052] Fig. 7Figure 1 shows a schematic exploded view of a lighting unit 10 according to the invention. The surface lighting element 50, shown only schematically, is connected at one narrow side via a flexible circuit board tab 57 to control and power electronics 34 of a control unit 20, the components of which are arranged on a circuit board 35. Above and below the circuit board 35, a lower housing part of the housing 22 and a housing cover 23 are shown, which, when assembled, form the housing 22 of the control unit 20. The butt joints between the housing 22 and the housing cover 23 can be made watertight by a sealant. The housing 22 has a compartment for a battery 30 or a rechargeable battery, as well as a membrane keypad 32 on its upper side.The battery compartment is located externally to the interior of the housing 22 and has its own sealing means not shown, for example one or two terminal screw plates which are screwed together with sealing rings into a suitable internal thread at the end of the battery compartment.

[0053] Also shown is a retaining washer 28 in the form of a toothed washer, spring washer, or star-shaped eyelet, which is pushed onto a pull-in pin 24 (not shown) on the inside of the upper half of the housing 22, which is guided through one of the eyelets 54 in the surface lighting body. Fig. 7 The pull-in pin 24 is concealed by the wall of the housing 22, as shown in the sectional view of the Fig. 8 However, it is visible.

[0054] The contacting of the electrical connecting lines of the surface lighting body 50 with the corresponding contacts on the circuit board 35 can be done in various ways, for example as described in DE 10 2020 116 917 A1, the full disclosure of which is to be included.

[0055] In addition to a conventional soldered connection, the surface lighting body 50 can alternatively be equipped, for example, with a circuit board 28, which is connected on its underside to the electrical leads on the surface lighting body 50 and has a pin header with parallel contact pins. In such a case, the main circuit board 26 has corresponding contact receptacles to receive the contact pins of the pin header. Such a connection alone is not mechanically stable and would immediately separate under tension. Therefore, in such a case, a cover or frame is preferably provided, which receives the end of the surface lighting body 50 in an opening and is screwed onto or attached to the housing 22.

[0056] Behind the circuit board, the surface-mounted light source 50 can be fitted with stop strips on at least one side, which may be sewn, glued, or otherwise attached. These prevent the surface-mounted light source 50 from being pulled out of the cover or frame. Together with the cover, they act as strain relief. The cover can also be equipped with sealing lips made of rubber, silicone, or other suitable materials against which the stop strips are pulled or pressed, thus reinforcing the sealing effect provided by the stop strips, particularly if they are designed as welt strips.

[0057] In Fig. 8 The housing 22 of a control unit 20 according to the invention is shown schematically, as well as two sectional views along section planes AA and BB, which are indicated in the central view.

[0058] The housing 22 encloses an interior 31 in which control electronics 34 are arranged, which for the sake of clarity are in Fig. 8The housing 22, shown above, encloses a lateral recess 25 on one side, which serves to receive one side of a surface lighting element 50. This lateral recess 25 is separated from the interior 31 of the housing by a side wall of the housing 22. Tension-receiving pins 24 are arranged in this lateral recess 25 as part of the housing 22 or are fixedly connected to the housing 22. The eyelets 54 of the surface lighting element 50 are slid onto these pins. The surface lighting element 50 is then secured to the tension-receiving pins 24 with locking washers 28. The connection with the tension-receiving pins 24 ensures that tensile loads of the surface lighting element 50 are primarily transferred to the housing 22 of the control unit 20, and not to the electrical connection to the control electronics.

[0059] For the electrical connection of the light-emitting diodes or other light sources of the surface lighting unit 50 to the control electronics 34, the surface lighting unit 50 has a flexible printed circuit board 55 on the side that is connected to the housing 22. This board has solder points or other connecting elements for connecting the leads leading to the light sources. The flexible printed circuit board 55 includes or is connected to a flexible printed circuit board extension 57, which has electrical conductors that terminate in connection points, such as solder points, at the end of the extension. This extension must be inserted into the interior 57 from the outside.

[0060] To ensure this connection is both hermetically sealed and stress-resistant, it comprises several components. First, the printed circuit board tongue 57 is guided through a narrow slot 26 in the side wall that defines the interior 31 of the housing 22. However, the printed circuit board tongue 57 does not enter the interior 31 directly, but rather a cavity 27 formed by the side wall of the housing 22 and an inner wall 27' directly behind the slot 26. The inner wall 27' obstructs the printed circuit board tongue 57, requiring it to be bent to pass around it. The cavity 27 is open in the direction of the bending of the printed circuit board tongue 57 towards the interior 31 and forms a basin shape, which is particularly well-suited for controlled filling with a sealant. The geometry of this chicane formed by the inner wall 27' is clearly visible in section AA.In this example, the circuit board tongue 57 makes two 90° bends in order to pass through the slot 26 into the interior 31.

[0061] After the PCB tongue 57 has been inserted, the cavity 27 can be filled with a hardening sealant that completely fills the cavity 27 or at least to the extent necessary to create a hermetic seal of the slot 26. Simultaneously, the sealant encloses the PCB tongue 57, particularly in its curved section, so that external tensile loads are transferred into the sealant and thus into the housing 22, and not to the electrical contact between the PCB tongue 57 and a circuit board 35 of the control electronics. Furthermore, this sealing geometry also protects the PCB tongue 57 from being pulled out of the sealant.

[0062] In addition to cavity 27, a second, smaller cavity (without reference numeral) is provided, which can be used in a similar manner for the passage of another, narrower printed circuit board tongue, which can be used, for example, for another membrane keyboard.

[0063] In the lower part of the Fig. 8 as well as section BB shows that a printed circuit board tongue 33 of a in Fig. 8 The membrane keypad 32 (not shown) is guided in a similar manner through a baffle to be filled with a sealant, which is formed by a trough-shaped cavity 29. This cavity is delimited by the outer wall of the housing and an inner wall 29' and is open on one side towards the interior 31 of the housing 22 of the control unit 20. This cavity 29 forms a baffle for the circuit board tongue 33 and can also be filled with a sealant to hermetically seal a corresponding slot for the circuit board tongue 33.

[0064] In the corners of the interior 31 of the housing 22, there are also protrusions from the base plate to receive the ends of screws, which are guided through the housing shell via threaded tunnels. This means the screws are physically located outside the housing shell and maintain a hermetic seal to the outside.

[0065] The Figures 9 and 10 show various perspective views of housing 22 from Fig. 8 , which includes slot 26 ( Fig. 9 ) as well as the geometry of the trough-shaped cavity 27 ( Fig. 10 ). While in Fig. 9 Since the circuit board tongues 33 and 57 are omitted, they are in Fig. 10 shown. Also shown in Fig. 9 The side opening 25 can be seen particularly well, which is separated from the interior 31 of the housing 22 of the control unit 20 by a wall, with the exception of the slot 26, the sealing of which is carried out in the manner described by filling the cavity 27.

[0066] Another detail that increases the application possibilities of the lighting unit 10 is an opening 37 in the side wall facing the receiving area lighting body 50, which is in Fig. 9 from outside and inside Fig. 10 visible from inside the housing 22. This opening 37 accommodates a pressure diaphragm designed to compensate for different external pressures. This can range from lower pressure at high altitudes, for example in the mountains or in an aircraft, to higher pressure underwater. The pressure diaphragm can, for example, be designed for a water column, i.e., a diving depth, of 2 m.

[0067] The opening 37 has a larger diameter on the outside than on the inside of the case 22 and therefore has a ring-shaped recessed area on its outside into which a round pressure membrane can be attached with a waterproof adhesive, which has the required protection class for water resistance.

[0068] Additionally, a frame-stiffening system can be provided for the flexible surface lighting body 50, which is not shown in Figures 8 to 10. Such a system can, for example, be made with an inflatable tube, as shown in Fig. 2The unit is shown equipped with a stiffening element that runs along the surface lighting body in an O-shape, U-shape, and / or X-shape. Alternatively, stiffening can also be achieved by means of hinged stiffening struts. Examples of such stiffening elements are described in patent application DE 10 2020 116 917 A1. Advantageously, in such cases, the frame structures are located outside the hermetic space of the housing 22 of the control unit 20. A stop for stiffening struts could, for example, be arranged or fixed to a protruding part of the housing 22 or the housing cover 23, or a blower unit could be used to inflate a hose-based stiffening element, so that the interior 31 of the control unit 20 remains watertight.

[0069] All features mentioned, including those discernible from the drawings alone as well as individual features disclosed in combination with other features, are considered essential to the invention, both individually and in combination. Inventive embodiments may be fulfilled by individual features or by a combination of several features. Reference symbol list

[0070] 10 Lighting unit 20 Control unit 22 Housing 23 Housing cover 24 Pull-out pin 25 Side mounting 26 Slot 27 Cavity 27' Inner wall 28 Locking washer 29 Cavity 29' Inner wall 30 Battery 31 Interior 32 Membrane keypad 33 Flexible PCB tongue 34 Control electronics 35 Circuit board 36 Wireless communication interface 37 Opening for pressure diaphragm 38 Pump 40 Remote control unit 50 Surface light source 52 Edge 54 Eyelet 55 Flexible circuit board 56 Light-active area 57 Flexible PCB tongue 58 LED light source 59 Circuit board 60 Electrical wiring 65 Fixing element 70 O-shaped stiffening frame 72 U-shaped stiffening frame 76 Mounting points 80 Circuit carrier 82 Cooling layer 84 Rain and dirt repellent layer 86 Diffusion layer 88 Waterproof coating 90 Reflective layer

Claims

1. Lighting unit (10) comprising a flexible flat lighting element (50) and a control unit (20), wherein the flat lighting element (50) comprises a flat carrier material with a, in particular textile-based, flexible flat circuit carrier (80), which is equipped on a front side with a plurality of light sources (58) that are connected by electrical lines (60) formed in or on the circuit carrier (80), wherein the control unit (20) is designed to supply power to and control the plurality of light sources (58) and comprises a housing (22) with electrical and / or electronic components and lines, which is arranged at an edge of the flat lighting element (50) and mechanically connected thereto, wherein, for connection to the control unit (20), the circuit carrier (80) of the flat lighting element (50) has at least one elongated flexible printed circuit board tongue (57) with conductor tracks, which is inserted into the control unit (20) through a slot (26) in a wall of the housing (22) of the control unit (20), characterized in that the housing (22) comprises an inner wall (27') located on the inside of the slot (26) defining a cavity (27) with the wall of the housing (22) having the slot (26), which is open on one side towards an interior space (31) of the housing (22) and forms a baffle through which the printed circuit board tongue (57) is guided from outside of the housing (22) into the interior of the housing (22) with at least one bend, in particular an S-shaped bend, wherein the cavity (27) with the printed circuit board tongue (57) passing through it is filled with a sealing compound.

2. Lighting unit (10) according to claim 1, characterized in that the edge of the flat lighting element (50) is accommodated in sections in the housing (22) of the control unit (20), wherein the housing (20) comprises a strain relief means (24) which absorbs tensile stresses between the housing (22) of the control unit (20) on the one hand and the flat lighting element (50) on the other hand and keeps them from the passage of the printed circuit board tongue (57) through the baffle, in particular from the electrical connections between the control unit (20) and the flat lighting element (50).

3. Lighting unit (10) according to claim 1 or 2, characterized in that the strain relief means (24) is designed as a clamping device or as a series of two or more strain relief pins (24) that are guided through a series of eyelets (54) designed to match the arrangement of the strain relief pins (24) in the flat lighting element (50), wherein in particular the carrier material is reinforced in the area of the eyelets (54), in particular by a double layer of the flexible flat circuit carrier (80).

4. Lighting unit (10) according to claim 3, characterized in that the eyelets (54) are designed as locking washers (24) or comprise locking washers (24) or are secured by locking washers (24) which, after being pushed onto the strain relief pins (24), prevent them from slipping back.

5. Lighting unit (10) according to one of claims 1 to 4, characterized in that two or more parts of the housing (22) of the control unit are sealed against each other in a watertight manner by means of a sealing compound applied along their joint edges.

6. Lighting unit (10) according to one of claims 1 to 5, characterized in that the flat lighting element (50) has a flexible, flat cooling layer (82) on a rear side of the circuit carrier (80), which is mechanically or materially connected to the circuit carrier (80), and / or a rain- and dirt-repellent layer (84), wherein in particular the cooling layer (82) is shielded from the outside by the rain- and dirt-repellent layer (84) or is designed as a rain- and dirt-repellent layer (84), and / or has a diffusion layer (86) and / or a directional grid on a front side of the circuit carrier (80), in particular a removable one, and / or the circuit carrier (80) is provided with a reflective surface, in particular an aluminium layer, below the light sources (58).

7. Lighting unit (10) according to one of claims 1 to 6, characterized in that the circuit carrier (80) with the light sources (58) and the electrical lines (60) is coated with a waterproof coating (88), in particular silicone, a lacquer, or a laminate, wherein the waterproof coating also covers the flexible printed circuit tongue at least as far as into the housing of the control unit.

8. Lighting unit (10) according to one of claims 1 to 7, characterized in that the control unit (20) comprises, in particular, waterproof operating elements, in particular a membrane keyboard (32), and / or comprises a wireless communication interface (36) via which the control unit (20) can be remotely controlled by means of a remote control unit (40) or a mobile terminal device.

9. Lighting unit (10) according to claim 8, characterized in that the membrane keyboard (32) has an elongated flexible printed circuit board tongue (33) with conductor tracks for electronic connection to electrical or electronic components in the housing (22), which is guided into the housing (22) through a further slot in a wall of the housing (22) and a cavity (29) filled with a sealing compound (29), which forms a baffle for the printed circuit board tongue (33).

10. Lighting unit (10) according to one of claims 1 to 9, characterized in that an opening (37) with a pressure membrane is provided in a wall of the housing (22) of the control unit (20), which is connected to an edge of the opening (37) in a watertight manner, wherein the pressure membrane is designed in particular for a water column of up to 2 m.

11. Method for manufacturing a lighting unit (10) with a flexible flat lighting element (50) and a control unit (20), in particular a lighting unit (10) according to one of claims 1 to 10, comprising the following steps: - Arranging the flexible flat lighting element (50) at the edge of a housing of the control unit (20), - threading an elongated flexible conductor board tongue (57) of the flexible flat lighting element (50) through a slot (26) in a wall of the housing (22) of the control unit (20) and a cavity (27) defined by an inner wall (27') with the wall of the housing (22) having the slot (26), and - creating a hermetic seal by filling the cavity (27) forming the baffle, including the threaded-through printed circuit board tongue (57), with a sealing compound.

12. Method according to claim 11, characterized in that, after threading and before or after establishing the hermetic seal, an electrical connection is established between one or more contact surfaces on the printed circuit board tongue (57) and one or more electrical or electronic components in the housing (22) of the control unit (20).

13. Method according to claim 11 or 12, characterized in that the flexible flat lighting device (50) is connected to the housing (22) after positioning and before or after threading and before or after establishing a hermetic seal, wherein, in particular, strain relief for the feedthrough of the printed circuit board tongue (57) is achieved by means of the hermetic seal.

14. Method according to one of claims 11 to 13, characterized in that a control element, in particular a membrane keyboard (32), is attached to the housing (22) of the control unit (20), wherein an elongated flexible printed circuit tongue (33) of the control element (32) is threaded into the housing through a slot and a cavity (29) arranged directly inside the housing of the slot and designed as a baffle (22) and the feed-through is then hermetically sealed by filling the cavity (29) forming the baffle with a sealing compound.

15. Method according to one of claims 11 to 14, characterized in that some or all of the method steps mentioned in claims 11 to 14 are performed with an at least partially open housing (22) of the control unit (29) and the housing (22) is closed after completion of the hermetic connection or connections, wherein, in particular, two or more parts of the housing (22) are sealed against each other before closing by means of a sealing compound applied along their joint edges.

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