Luminaire consisting of at least one LED module

Abstract

Luminaire with LED light-emitting diodes (3), comprising at least: · a module (1) including: a support (5) made of a rigid profile; a printed circuit board (2) fixed to a first face of the support (5), including a plurality of LEDs (3); a light-diffusing cover (6) attached to the support (5), capable of diffusing the light from the LEDs (3) of the module (1); two sealing flanges placed at the axial ends of the printed circuit board (2); means for attaching (25) to the support (5) consisting of recesses made in a second face of the support (5); · a harness (9) for connection to a power source, comprising a flexible cable equipped with a connector intended to connect to an end connector (4) of an end module (1) of the luminaire.

Description

Title of the invention: Luminaire consisting of at least one light-emitting diode module

[0001] The present invention relates to the field of lighting design, and in this instance concerns luminaires based on LED light-emitting diode modules. Within the scope of the invention, these luminaires are therefore designed in a modular fashion, meaning that they are composed of one or more individual LED modules rather than a single, pre-designed light source luminaire with predetermined dimensions. The separate units that make up each module can be easily assembled to form different configurations, chosen according to specific lighting needs, given that LEDs are known for their energy efficiency and extensive control capabilities.

[0002] This modular structure offers numerous advantages, the most immediate being that the luminaires can be adapted much more precisely not only to lighting requirements but also to a specific environment. Secondly, if a module fails, it is sufficient to replace the defective module rather than the entire luminaire. Finally, the modular organization allows for control, even individual control, of the modules in order to adjust parameters such as luminous intensity, color temperature, or even other characteristics of the light.

[0003] The application context in this case is the production of plants in a controlled environment, and more specifically the equipment that enables such production. This equipment schematically consists of controlled atmosphere chambers equipped with actuators and sensors that allow the regulation of a number of parameters such as temperature, humidity, gas flow (air, etc.), the degree of irrigation, the quantity of nutrients supplied to the plants being grown there, etc. And also, of course, light, the parameter that is the subject of the present invention. It must be possible to offer an optimized lighting solution for each controlled environment plant production application.

[0004] However, most installations using LED luminaires such as those found in industry are inefficient and unprofitable, because the energy and financial break-even point requires adapting the lighting solution to each application. Conventional manufacturers obviously cannot offer customized solutions for every application; the economic constraint would prove far too high, in any case incompatible with the price levels charged. for such luminaires, and directly impacting the cost of the entire controlled atmosphere enclosure.

[0005] Existing lighting systems have technical characteristics such as a fixed spectrum, fixed dimensions not suited to cropping systems, etc., which in practice lead to a decrease in agronomic and energy performance. While LED light strips do exist and are adaptable to various environments, they have low energy efficiency and a short lifespan.

[0006] The present invention remedies these shortcomings by proposing luminaires for controlled atmosphere enclosures that meet two apparently opposing and irreconcilable constraints, namely, both being easily adaptable to many different environments and having a configuration designed to allow manufacturing on an industrial scale.

[0007] To this end, the luminaire of the invention, conventionally made from LED light-emitting diodes, is such that it consists of at least: • a module comprising: - a support consisting of a rigid profile; - a printed circuit board fixed to one side of the support, including a plurality of light-emitting diodes forming at least one axial light channel, and two end connectors, each channel of a module being chainable to a channel of an adjacent module via at least one of the two end connectors; - a light diffusion cover attached to the support, covering the printed circuit board and capable of diffusing the light from the module's diodes; - two sealing flanges placed at the axial ends of the printed circuit board and fixed to the rigid support; - means of attachment to the support consisting of recesses made in a second face of the support oriented opposite to the first face supporting the printed circuit board; • a harness for connection to a power source, comprising a flexible cable equipped with a connector designed to connect to an end connector of an end module of the luminaire.

[0008] The invention is therefore based, as mentioned previously, on identical or very similar modules, arranged in such a way as to allow for optimal adjustment to the constraints of the specific application intended for the luminaire. Standardization of the modules is the rule, with the differentiating elements between them being reduced as much as possible, while still allowing adaptation to the best suited to all possible plant production recipe scenarios and the light coverage required in each specific application.

[0009] The differences arise in particular from the fact that the modules are equipped with connectors that may differ from one module to another. The luminaires of the invention in most cases comprise several associated LED modules, which are then fixed to each other by means of said connectors, which depend on the immediate environment of each module, in terms of connectivity.

[0010] More specifically, the configuration of the end connectors of each module of the luminaire actually depends on the number of modules of the luminaire and the position of each module in the luminaire, the end connectors of the luminaire being board-to-wire connectors, and the connectors placed inside the luminaire being board-to-board connectors.

[0011] The wire-to-board connectors of a module at the end of the luminaire chain are Designed to connect to a harness connector containing wires, including power supplies, the board-to-board connectors are capable of connecting to another identical module—at least from the perspective of the electronic circuitry, including the LEDs. A module can therefore be equipped with two harness connectors, or one harness connector and one connector for linking to another module, or even two connectors allowing it to be connected to two adjacent modules. The idea is that the electronic circuit design makes the modules suitable for daisy-chaining, allowing for easy integration into any lighting configuration.

[0012] According to the invention, preferably, the board-to-wire connectors are of the blade cage type and the board-to-board connectors are of the male pin and female socket type. The blade cage connectors allow for solderless and permanent connection of the power harness. The female socket of the board-to-board connectors is positioned to prevent the presence of live protruding parts when one end of the module is free. The connectors are mounted on the board using a surface-mount method, with reflow soldering to the copper traces etched at each end of the printed circuit board.

[0013] This assembly can be carried out during the module manufacturing process, at the same time as the diodes are installed, or at a later stage during the luminaire assembly, in order to allow for optimal management of module differentiation on the production line. Indentations provided at the ends of each module, allowing for any connector configuration, make it possible to assemble the connectors during production. It should be noted that keying features are also provided on the modules to facilitate assembly and prevent the installation of a module in the wrong direction.

[0014] Generally, each luminaire with at least one module is equipped with two cables at its ends (integrated into the aforementioned harnesses), allowing for individual power supply to the luminaire. To simplify the wiring of certain lighting systems, the luminaire may have a cable on only one side, or the cables may be installed in such a way as to allow for the daisy-chaining of several luminaires, thus constituting a single electrical circuit in series or parallel, or any combination thereof.

[0015] According to one possible configuration of the luminaire of the invention, the flanges may consist of a flexible insert inserted into a rigid cap, said flanges being fixed to the support by fastening means ensuring the application of axial pressure of the flange against the end of said support, and provided with an opening for the passage of the flexible harness cable. The flexible insert is, for example, made of rubber or silicone. It plays a predominant role in the sealing. The cap, for its part, is made of rigid material, such as ABS, and fixed to the support, for example, by means of two screws with axes parallel to the longitudinal axis of the support. The sealing function is achieved in practice by the pressure exerted on the flexible insert by the fastening means, which force it into contact with the ends of the support and the cap.The insert also exerts concentric pressure around the harness cable, preserving the seal on that side, the dimensions of the opening provided in the flexible insert being designed for this purpose.

[0016] The cover must allow the diffusion of light from the light sources, namely the diodes, and secondarily ensure the protection and sealing of the luminaire. It acts as a diffuser of the light rays in order to improve lighting coverage by modifying the path of said light rays. In this respect, preferably, the outer face of the diffusion cover is smooth. Additionally, at least a portion of the inner face of the cover located opposite the printed circuit board may have raised features, designed in such a way as to help redirect the light rays for better coverage. Preferably, these raised features may have an axial geometry, such as axial grooves.

[0017] Experience in horticultural applications shows that the conventional diffusion pattern of diodes (in a straight line from the source) results in shadow areas on the crop, thus limiting the surface area actually reached by the light. This phenomenon can be avoided by perturbing the path of the rays to force them to diffuse in different directions. The solutions generally adopted for this purpose are either the use of secondary optics (lenses placed in front of the diodes), either the use of a semi-transparent opal material for the hood. Both solutions result in a significant loss of luminous flux, 5 to 10% compared to the basic solution using only diodes, in addition to an extra cost for the first solution since it involves an additional part.

[0018] The solution adopted in the present invention therefore consists of using a translucent cover whose inner curvature alone can be profiled according to different profile configurations to modulate the diffusion pattern, as will be seen in more detail below. The outer curvature remains unchanged, providing a smooth surface that allows for easy cleaning of the luminaires while preventing the accumulation of dust and debris that could—over time—reduce the luminous flux produced by the luminaire and thus its energy efficiency. Compared to existing configurations as mentioned previously, the solution of the invention retains a translucent material of similar thickness and does not require the addition of any extra parts. It does not generate a significant loss of light, and therefore improves net energy efficiency.Moreover, the manufacturing processes for such hoods are simple (for example, by extrusion of PMMA or PC).

[0019] According to one possible configuration, the luminaire of the invention may include a liquid-cooling heat sink attached to the mounting means present on the rigid support. These cooling means, for example, water cooling, are not essential and are therefore optional. It is indeed possible to provide for simple cooling of the luminaire by ambient air, but depending on the required thermal conditions, which can be very precise in such a controlled-atmosphere chamber for plant production, heating the air in the chamber by the LEDs may not always be desirable.

[0020] This is the case, for example, when a setpoint temperature for the air inside the enclosure must remain very stable and relatively low. In this case, it is easier to regulate the temperature using water cooling than to use ambient air, which risks heating the interior volume in a less easily controllable way. Such a liquid cooling system also makes it possible to remove the heat produced by the lighting fixtures from the source, for the purpose of recovering heat for use, for example, by climate control systems within the enclosure. It is thus possible to reduce the thermal loads and therefore the energy consumption of the enclosure.

[0021] According to the invention, the liquid-cooled heat sink can consist of a profile with an internal conduit and two hydraulic end fittings, the profile having an external face with ridges that fit into the recesses of the profile attachment means of the support. The relative positioning of one with respect to the other is then immediate, for example when dealing with parallel ribs. Axial elements are inserted into parallel channels machined into the luminaire support, allowing for further attachment using various known methods. This configuration, with its nested counterforms, also enables improved dissipation of heat emitted by the LEDs within the luminaire module to the heat sink.

[0022] Such an external, molded heat sink, which is installed—by means of adhesive, screws, or any other permanent or removable fastening method—onto the heat sink, conforming to its shape, is traversed by a heat transfer fluid such as water. The two hydraulic connections at the ends allow connection to an external cooling circuit. The temperature of the electronics is maintained at an optimal value, which also increases luminous efficiency and extends the lifespan of the diodes. Finally, the reduction of sensible heat input into the climatic chamber prevents microclimate phenomena and reduces the energy consumption of any air conditioning system potentially associated with such a chamber.

[0023] Thus, the lost heat can, for example, be recovered for needs related to the air treatment process (dehumidification) or other external processes (drying chamber, space heating, etc.), as it is much easier to channel via a heat transfer fluid than to manage it via convection in the ambient air. Furthermore, since the ideal operating temperature of the diodes is close to the temperature ranges used for plant production (10 to 30°C), it is also possible to dissipate this heat almost free of charge throughout the year by releasing it to the outside via an air cooler or a geothermal system, rather than using a refrigeration unit that consumes electricity to generate the cooling.

[0024] The modules, and more generally the luminaires, can be attached to one another in multiple ways to achieve a more sophisticated configuration. Thus, the luminaire of the invention may include a profile for attaching it to a second luminaire, said profile being fixable to the attachment means present on the rigid support, and having at least two external faces provided with raised features that fit into the recesses of said attachment means. In one possible configuration, these may be two external faces located opposite each other, for the creation of a set of two luminaires oriented in opposite directions in a generally transverse direction.

[0025] If the connecting profile is equipped with an internal conduit, it can then be another option for a liquid-cooling heat sink, the external heat sink being symmetrical in this case and also allowing two luminaires to be joined together, as will be described in more detail later. This type of connecting profile This represents an optimal solution for interlighting, allowing the illumination of two facing vertical planes (e.g., rows of tomatoes or vertical growing walls). Other configurations are also possible for this connecting profile, such as triangles, crosses, or any other shape, enabling the diffusion of light using multiple luminaires oriented in different directions, for other types of applications (vertical towers, rotating cylinders with horizontal or vertical axes, etc.). Given the specific and low-volume nature of these applications, the solution of the invention allows for a common modular platform (and therefore, assembly at a lower cost using standardized methods) that can be customized to best suit the specific site conditions, always with the aim of delaying the differentiation of basic modules as much as possible.

[0026] Preferably, the rigid profile, the liquid cooling heat sink profile and the attachment profile are made of aluminium, a light metal which conducts heat well.

[0027] Preferably, grooves may be formed in the outer lateral faces of the support profile, suitable for receiving flexible tabs of a fixing clip. To secure the luminaire, for example, to a wall, these lateral grooves allow the installation of an elastic metal fixing clip or any other retaining device adapted to the configuration of the grooves, an example of which will be described later.

[0028] Other objects and advantages of the present invention will become apparent from the following description, which relates to an embodiment given by way of example only. Understanding this description will be particularly facilitated by reference to the accompanying drawings, in which:

[0029] [Fig. 1] shows a simplified diagram of the printed circuit board of the LED module of a luminaire of the invention;

[0030] [Fig.2] represents an exploded perspective view of a module equipped with a heat sink for liquid cooling;

[0031] [Fig.3] shows, in perspective view, the side of the board containing the diodes electroluminescent, an assembled module;

[0032] [Fig.4] illustrates, in perspective view showing the side opposite to the previous one, a module assembled with air cooling;

[0033] [Fig.5] reproduces the previous figure with the addition of a heat sink for Liquid cooling.

[0034] [Fig. 6] shows a partial perspective view of a two-module luminaire attached.

[0035] [Fig.7] shows cross-sectional views of modules respectively without heat sink additional, with a liquid cooling heat sink and with a profile attachment of a second module also acting as a heat sink for liquid cooling;

[0036] [Fig-8] shows sectional views of modules with three different configurations of diffuser covers for the light emitted by the light-emitting diodes;

[0037] and [Fig.9] show a schematic representation of a liquid cooling system with heat recovery.

[0038] Figure 1 shows a simplified representation of a printed circuit board 2 of a module 1 of a luminaire of the invention, on which a number of components are mounted, primarily light-emitting diodes 3 (LEDs) and resistors. In the example configuration shown in the figure, these LEDs 3 are arranged along a line forming, in this case, the central longitudinal axis of the printed circuit board 2 of module 1. This configuration is, however, only one possible example, and there may, in particular, be several lines of LEDs forming several parallel lighting channels, which can be linked with the channels of other modules after connection.

[0039] The design of module 1 as shown in the figure allows the use of a single circuit version regardless of the module 1's position in the luminaire, assuming that several modules 1—and therefore several printed circuit boards 2—are axially assembled. In other words, whether module 1 is located at one end, at the beginning or end of the chain, or in the middle, among one or more "internal" modules that do not form an end, the electronic circuit itself is identical. Only the edge connectors change, which are adapted to the immediate environment of module 1, that is, in practice, to the nature of the connections coming from a harness or another module.This, however, implies slightly differentiating the modules 1 according to their future destination during the (preferably robotic) component placement stage of the module or, as mentioned, on the assembly line at the end of the luminaire manufacturing process. The connectors are assembled on the board, as previously mentioned, by surface mounting with reflow soldering onto the copper traces present at each end of the printed circuit board, either during module manufacturing or during luminaire assembly. The connectors 4 appearing in [Fig. 1] are shown schematically and do not necessarily accurately represent the different types of connectors used in practice.

[0040] According to the invention, for a luminaire with a single module 1, the two ends of the card 2 are equipped with 4-wire card-to-wire connectors allowing connection to the harnesses carrying the power cables of the single-module luminaire. For a luminaire with two modules 1, the central junction between two modules 1 is made with 4-wire card-to-card connectors and the free ends are equipped with 4-wire connectors A wire-to-wire card allows connection to the luminaire's power cables, which in this case is a two-module luminaire. If the luminaire size increases further, i.e., assuming a luminaire with 3 or more PCBs, at least one intermediate module 1 is added, in this case having 4-to-card connectors at its two ends.

[0041] With reference to [Fig.2], a module 1 consists of a support 5 preferably made of aluminum, on one face of which is placed the printed circuit board 2 equipped with its diodes 3 (see in [Fig.3]), covered with a translucent hood 6 and the end of which has a connector 4. The axial end of the module 1 has a flange composed of a flexible sealing insert 7 and a rigid cap 8 fitted one into the other. A harness 9 comprising at least one power cable is connected to the connector 4, the cable being fixed rigidly to the support 5 at the output of the connector 4 via a strain relief device, for example a metal flange 10 screwed onto the support 5. The two parts 7, 8 constituting the flange are fixed, at each end, by fastening means ensuring the exercise of axial pressure against said end, the flexible insert 7 then ensuring the seal with the axial end of the support 5 and the cover 6.A seal is similarly achieved with the flexible cable of harness 9, the insert being tightened around said cable at the level of the opening made in it to allow the passage of the cable.

[0042] A fixing clip 11 is provided to clip elastically into lateral grooves 12 of the support 5, said clip 11 being able for example to be attached to a fixed wall of a controlled atmosphere plant production chamber, according to the field of the invention.

[0043] A liquid-cooling heat sink 20, the attachment of which to the support is specified in [Fig.7], is shown in [Fig.2], with its end hydraulic fittings 21 and its internal conduit 22. This is an optional piece of equipment; the module 1 shown is capable of operating without this addition, with heat dissipation into the ambient air around the module 1, as shown assembled in Figures 3 and 4. The aluminum profile of the liquid-cooling heat sink 20, when mounted, forms a unit with the rest of the module 1 (see [Fig.5]).

[0044] This profile can take an alternative form for the additional attachment of a second module 1', and consequently be used as an attachment profile 20' for this other module 1', in the manner shown in [Fig. 6]. This configuration, particularly when used vertically, can be installed, for example, between rows of tomatoes, in an enclosure configured for this purpose.

[0045] The cross-sectional profile of the support profiles 5, the heat sink 20 and the attachment 20' appears in [Fig.7]: the attachment means 25 present on the support 5 consist of recesses in the form of axial grooves made in the face of the support 5 oriented opposite to the face receiving the printed circuit board 2. These axial grooves run along the entire length of the face. Their profile follows the external profile of reliefs 26 formed in the form of ribs, so as to achieve a tight fit in these counter-formed configurations, which can then be fixed to one another. Module 1 (on the left of [Fig. 7]) can therefore become a compact module with a cooler when a profile 20 is fixed to it (in the center of [Fig. 7]) and a compact double module 1,1' by fixing a connecting profile 20' between two modules 1 and 1' (on the right of [Fig. 7]). The latter can also include a liquid passage 22 and consequently also serve as a heat sink for liquid cooling.

[0046] The hood can also take several forms, as shown in [Fig. 8], in which three versions are shown, each with a simulation of the trajectory of four light rays. On the left, the inner face of the hood 6 is smooth, as is the outer face, which remains smooth in all three configurations shown. In the center and on the right, slightly different indentations are used on the inner face of the hood 6. Ultimately, the desired effect on the multiplicity of rays is to disrupt their trajectory, which is clearly shown in the figure, to force them to diffuse in different directions in space, in the most homogeneous way possible, and to significantly increase their territorial coverage.

[0047] Figure 9 shows a very simplified diagram of a hydraulic heat recovery circuit, in the case of using heat sinks 20, 20' for liquid cooling. "Lost" heat is recovered, for example, for needs related to the air treatment process (dehumidification) or for other external processes (drying chamber, space heating, etc.), or even for other customer processes. Heat is much easier to channel in a heat transfer fluid, whereas managing its convection in ambient air is difficult. It is also possible to dissipate this heat almost free of charge throughout the year by releasing it to the outside via an air cooler or a geothermal system, rather than using a refrigeration unit that consumes electricity to generate the cooling.

[0048] The predetermined axial dimension of each module 1 is chosen so that the length of the luminaires finally obtained can be a multiple of 600 mm (600 mm, 1200 mm, 1800 mm...), a length which allows the luminaire to be properly adapted to the standard dimensions of hydroponic growing systems.

[0049] One of the major advantages of using LED technologies is the extensive possibilities for electronically controlling LED luminaires, via LED controllers often referred to as "LED drivers," which are an essential component of lighting systems using light-emitting diodes. In practice, they allow for the regulation of the power supply provided to the LEDs in order to control their Brightness, color, and sometimes even color temperature allow for switching from warm to cool light as needed. The controllers can be programmed for dynamic lighting effects or to follow predefined scenarios, thus fully contributing to the management of optimized lighting conditions for each plant production application in a controlled environment.

[0050] The example configuration shown in the figure should not be considered exhaustive of the invention, which includes variants, for example in the arrangement of the components implanted on the printed circuit board 2 - such as the addition of other diode channels 3 to form from 1 to n channels or luminaires that can be chained in series or in parallel - or the shapes of the different components of the system.

Claims

Demands

1. LED (3) light-emitting diode luminaire, consisting of at least one module (1) comprising: - a support (5) consisting of a rigid profile; - a printed circuit board (2) fixed to a first face of the support (5), including a plurality of light-emitting diodes (3) forming at least one axial light channel, and two end connectors (4), each channel of a module (1) being chainable to a channel of an adjacent module (1) via at least one of the two end connectors (4); - a light diffusion cover (6) attached to the support (5), covering the printed circuit board (2) and capable of diffusing the light from the diodes (3) of the module (1); - two sealing flanges placed at the axial ends of the printed circuit board (2) and fixed to the rigid support (5); characterized in that: - attachment means (25) to the support (5) of the module (1) consist of recesses made in a second face of the support (5) oriented opposite to the first face supporting the printed circuit board (2); - the flanges are composed of an insert (7) of flexible material inserted into a cap (8) of rigid material, said flanges being fixed to the support (5) by means of fixing ensuring the exercise of an axial pressure of the flange against the end of said support (5), and provided with an opening for the passage of the flexible cable of a harness (9); - the luminaire (3) includes at least one such harness (9) for connection to a power source, comprising a flexible cable equipped with a connector intended to connect to an end connector (4) of an end module (1) of the luminaire.

2. Luminaire according to the preceding claim, characterized in that the configuration of the end connectors (4) of each module (1) of the luminaire depends on the number of modules (1) of the luminaire and of the position of each module (1) in the luminaire, the end connectors (4) of the luminaire being board-to-wire connectors, and the connectors (4) placed inside the luminaire being board-to-board connectors (4).

3. Luminaire according to the preceding claim, characterized in that the (4) wire-to-board connectors are of the blade cage type and the (4) board-to-board connectors are of the male pin and female socket type.

4. Luminaire according to any one of the preceding claims, characterized in that the outer face of the diffusion hood (6) is smooth.

5. Luminaire according to the preceding claim, characterized in that at least a portion of the inner face of the cover (6) located opposite the printed circuit board (2) has reliefs.

6. Luminaire according to the preceding claim, characterized in that said reliefs have axial geometry, of the axial groove type.

7. Luminaire according to any one of the preceding claims, characterized in that it comprises a liquid cooling heat sink (20) fixed to the attachment means (25) present on the rigid support (5).

8. Luminaire according to the preceding claim, characterized in that the liquid cooling dissipator (20) consists of a profile having an internal conduit (22) and two hydraulic end fittings (21), the profile having an external face having reliefs (26) fitting into the recesses of the attachment means (25) of the support profile (5).

9. Luminaire according to any one of the preceding claims, characterized in that it comprises an attachment profile (20') to a second luminaire, said attachment profile (20') being fixable to the attachment means (25) present on the rigid support (5), and comprising at least two external faces provided with reliefs (26) fitting into the recesses of said attachment means (25).

10. Luminaire according to the preceding claim, characterized in that the attachment profile (20') is provided with an internal conduit (22).

11. Luminaire according to any one of the preceding claims, characterized in that the rigid profile (5), the liquid cooling dissipator profile (20) and the attachment profile (20') are made of aluminium. 14

12. Luminaire according to any one of the preceding claims, characterized in that grooves (12) are made in the outer lateral faces of the support profile (5), suitable for receiving flexible tabs of a fixing clip (11).

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