Luminaire consisting of at least one light-emitting diode module

Abstract

Luminaire with LED-type light-emitting diodes (3), consisting of at least: a 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); a light diffusion cover (6) secured to the support (5), 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); attachment means (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 designed to be connected 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 case relates to luminaires based on LED light-emitting diode modules. In the context of the invention, these luminaires are therefore designed in a modular manner, which means that they are composed of one or more individual LED modules rather than a single light source luminaire provided in advance with predetermined dimensions. The separate units that form each module can be easily assembled to form different configurations, chosen according to specific lighting needs, knowing that LEDs are known for their energy efficiency and their extensive control possibilities.

[0002] This modular structure has many 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. Secondarily, in the event of a module failing, it is sufficient to replace the defective module rather than the entire luminaire. The modular organization finally allows for control, if necessary individually, of the modules in order to adjust parameters such as light 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 precisely the equipment that allows such production. It is schematically a question of controlled atmosphere enclosures, equipped with actuators and sensors that make it possible to regulate a certain number of parameters such as temperature, humidity, gas flows (air, etc.), the degree of irrigation, the quantity of nutrients supplied to the plants grown there, etc. And also, of course, light, a parameter that is the subject of the present invention. It is necessary to be able to propose an optimized lighting solution for each application of plant production in a controlled environment.

[0004] However, most installations using LED luminaires such as those found in industry are inefficient and unprofitable, because the energy and financial balance point requires adapting the lighting solution to each application. Conventional manufacturers obviously cannot offer tailor-made solutions for each 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 adapted to cultivation systems, etc., which in practice lead to a reduction in agronomic and energy performance. While LED light strips already exist, which are adaptable to various environments, they have low energy efficiency and a reduced lifespan.

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

[0007] For this purpose, the luminaire of the invention, conventionally made from LED type light-emitting diodes, is such that it is made up of at least: • a module comprising: - a support made of a rigid profile; - a printed circuit board fixed on a first face 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 secured 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 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 before, on identical or very similar modules, arranged in such a way that there is a possibility of optimal adjustment to the constraints of the specific application intended for the luminaire. Standardization of the modules is the rule, the elements of differentiation between them being as much as possible reduced, however allowing adaptation to the best suited to all possible cases of plant production recipes and the light coverage required in each specific application.

[0009] The differences result in particular from the fact that the modules are equipped with connectors which may be different from one module to another. The luminaires of the invention in fact comprise in most cases several associated light-emitting diode 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 board-to-wire connectors of a module at the end of the luminaire chain are intended to connect to a connector on the harness containing the wires, in particular the power supply, and the board-to-board connectors are capable of connecting to another identical module - at least from the point of view of the electronic circuit including the LEDs. A module can therefore be equipped with two connectors for connection to a harness, or with a connector for connection to a harness and a connector for connection to another module, or even be equipped with two connectors allowing its connection to two adjacent modules. The idea is that the design of the electronic circuit makes the modules suitable for being chained together so as to easily adopt any luminaire 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 the power harness to be connected without soldering and in a permanent manner. The female socket of the board-to-board connectors is positioned so as to avoid the presence of live protruding parts when one end of the module is free. The assembly of the connectors on the board is carried out according to a surface mounting method, with reflow soldering on the copper tracks etched at each end of the printed circuit board.

[0013] This assembly can be done during the manufacture of the module, at the same time as the installation of the diodes, or in a later stage during the assembly of the luminaire, in order to allow optimal management of the differentiations between modules at the level of the production line. Imprints provided at the ends of each module, allowing any connection configuration to be accommodated, make it possible in particular to assemble the connectors during production. It should be noted that keyways are also provided on the modules to facilitate assembly and prevent a module from being installed the wrong way around.

[0014] Generally, each luminaire with at least one module is equipped with 2 cables at its ends (integrated into the aforementioned harnesses), allowing the individual power supply of the luminaire. In order to simplify the wiring of certain lighting systems, it is possible for the luminaire to have a cable on only one side, or even for the cables to be installed in such a way as to make it possible to connect several luminaires in a chain, thus de facto constituting the same electrical circuit in series or in parallel, or any combination of the two.

[0015] According to a possible configuration of the luminaire of the invention, the flanges may be composed of an insert made of flexible material inserted into a cap made of rigid material, said flanges being fixed to the support by fixing means ensuring the exertion of axial pressure of the flange against the end of said support, and provided with an orifice for the passage of the flexible cable of the harness. The insert made of flexible material is for example made of rubber or silicone. It is this which plays a predominant role in sealing. The cap is provided in rigid material, of the ABS type, and fixed to the support for example by means of 2 screws with an axis parallel to the longitudinal axis of the support. The sealing function arises in practice from the pressure exerted on the flexible insert by the fixing means, which push it back under pressure in contact with the ends of the support and the cover.The insert also exerts concentric pressure around the harness cable, preserving the seal on this side, the dimensions of the hole provided in the flexible insert being provided for this purpose.

[0016] The cover must allow the diffusion of light coming from the light sources that are the diodes, and secondarily ensure the protection and sealing of the luminaire. It has a role of diffusing the light rays in order to improve the coverage of the lighting by modifying the trajectory of said light rays. In this respect, preferably, the outer face of the diffusion cover is smooth. In a complementary manner, at least a portion of the inner face of the cover located opposite the printed circuit board may have reliefs, provided in such a way that they help to reorient the light rays with a view to better coverage. More preferably, said reliefs may have axial geometry, of the axial groove type.

[0017] Experience in horticultural applications shows in fact that the classic diffusion pattern of diodes (in a straight line from the source) causes shadow zones on the crop, which limits the surface actually reached by the light, a phenomenon which can be avoided by disturbing the trajectory of the rays to force them to diffuse in different directions in space. The solutions generally adopted to do this are either the use of secondary optics

[0018] (lenses placed in front of the diodes), or the use of a semitransparent opaline material for the production of the cover. These two solutions result in a significant loss of luminous flux, from 5 to 10% compared to the basic solution simply comprising diodes, in addition to an additional cost for the first solution since it involves an additional part.

[0019] The solution adopted in the present invention therefore consists of using a translucent cover of which only the inner curvature can be profiled according to different profile configurations to modulate the appearance of the diffusion, as will be seen in more detail below. The outer curvature remains unchanged, which provides a smooth surface allowing easy cleaning of the luminaires while avoiding the incrustation of dust and debris which could - over time - attenuate the luminous flux produced by the luminaire and therefore 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 additional part(s). It does not generate significant loss of light, and therefore makes it possible to improve net energy efficiency.The manufacturing processes for such covers are also simple (for example by extrusion of PMMA or PC).

[0020] According to a possible configuration, the luminaire of the invention may comprise a heat sink for liquid cooling, fixed to the attachment means present on the rigid support. These cooling means, for example by water, are not essential and are therefore optional. It is indeed possible to provide simple cooling of the luminaire by the ambient air but, depending on the thermal conditions required, which may be very precise in such a controlled atmosphere enclosure for the production of plants, heating the air in the enclosure by the LEDs may not always be desirable.

[0021] This is the case, for example, in the event of an air temperature setpoint in the enclosure that must remain very stable and relatively low. In this case, it is easier to regulate the temperature using water cooling means than to use the ambient air, which risks heating the interior volume in a less easily controllable manner. Such a liquid cooling vector also makes it possible to evacuate the heat produced by the luminaires from the source, with the aim of recovering the heat for, for example, management systems for the enclosure's climatic parameters. It is thus possible to reduce the thermal loads and therefore the energy consumption of the enclosure.

[0022] According to the invention, the liquid cooling heat sink may consist of a profile provided with an internal conduit and two end hydraulic connections, the profile having an external face provided with reliefs fitting into the recesses of the attachment means of the support profile. The relative positioning of one by relation to each other is then immediate, for example when it comes to axial parallel ribs inserted into parallel channels made in the luminaire support, additional fixing by various known means then being possible. Such a configuration with nested counterforms also allows better dissipation of the heat emitted by the LEDs in the luminaire module towards the heat sink.

[0023] Such an external counter-shaped heat sink, which is installed - by means of an adhesive, screws or any other permanent or removable fixing means - on the heat sink by matching its shape, is crossed 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, also making it possible to increase the luminous efficiency and extend the life of the diodes. The reduction of the sensible heat input in the climatic chamber finally makes it possible to avoid micro-climate phenomena and to reduce the energy consumption of an air conditioning system possibly associated with such an enclosure.

[0024] 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.), being much easier to channel via a heat transfer fluid rather than being managed via convection in the ambient air. In addition, since the ideal operating temperature of the diodes is close to the temperature regimes used for plant production (10 to 30°C), it is also possible to dissipate this heat almost free of charge all year round, by evacuating it to the outside via an air cooler or a geothermal installation, rather than using a refrigeration device consuming electricity to generate the cooling.

[0025] The modules, and more generally the luminaires, can be attached to each other in multiple ways to achieve a more complete configuration.

[0026] Thus, the luminaire of the invention may comprise a profile for attachment to a second luminaire, said attachment profile being fixable to the attachment means present on the rigid support, and comprising at least two external faces provided with reliefs fitting into the recesses of said attachment means. According to a possible configuration, these may be two external faces located opposite one another, for the creation of a set of two luminaires oriented opposite one another in a generally transverse direction.

[0027] If the connecting profile is provided with an internal conduit, it can then be another option of heat sink for liquid cooling, the external heat sink being in this case symmetrical and allowing moreover to assemble two luminaires together, as will be described in more detail below. This type of connecting profile represents an optimal solution for "interlighting" type lighting, allowing to illuminate 2 vertical planes facing each other (e.g. rows of tomatoes, or vertical growing walls). It is also possible to imagine other configurations for this connecting profile, in triangle, cross or any other shape allowing to diffuse the lighting by means of several luminaires oriented in different directions, for other types of applications (vertical towers, rotating cylinders with horizontal or vertical axis, etc.). The applications being specific and low volume, the solution of the invention makes it possible to keep a common modular platform (and therefore assembled at a lower cost in a standardized manner) which is customizable so as to be configured as close as possible to the field, always with the idea of ​​delaying as much as possible the differentiation of the basic modules.

[0028] Preferably, the rigid profile, the liquid cooling heat sink profile and the connecting profile are made of aluminum, a light metal which conducts heat well.

[0029] More preferably, grooves may be made in the lateral outer faces of the support profile, capable of receiving flexible tabs of a fixing clip. To secure the luminaire, for example to a wall, said lateral grooves de facto allow the installation of an elastic metal fixing clip or any other holding device adapted to the configuration of the grooves, an example of which will be described below.

[0030] Other aims and advantages of the present invention will become apparent during the description which follows, relating to an embodiment which is given only as an indicative example. The understanding of this description will be facilitated in particular by reference to the attached drawings, in which:

[0031] [Fig. 1] shows a simplified diagram of the printed circuit board of the light-emitting diode module of a luminaire of the invention;

[0032] [Fig.2] represents an exploded perspective view of a module provided with a liquid cooling heat sink;

[0033] [Fig.3] shows, in perspective view, the side of the card containing the diodes electroluminescent, an assembled module;

[0034] [Fig.4] illustrates, in perspective view showing the side opposite to the previous one, a module assembled air-cooled;

[0035] [Fig.5] takes up the previous figure with the addition of a heat sink for liquid cooling.

[0036] [Fig.6] shows a partial perspective view of a two-module luminaire attached.

[0037] [Fig.7] shows sectional views of modules respectively without an additional heat sink, with a heat sink for liquid cooling and with a connecting profile of a second module also acting as a heat sink for liquid cooling;

[0038] [Fig.8] shows sectional views of modules with three different configurations of covers for diffusing the light emitted by the light-emitting diodes;

[0039] and [Fig.9] shows a schematic representation of a liquid cooling system with heat recovery.

[0040] [Fig. 1] shows in a simplified manner a printed circuit board 2 of a module 1 of a luminaire of the invention, on which a certain number of components are installed, including mainly light-emitting diodes 3 (LEDs) and resistors. These light-emitting diodes 3 are placed, in the configuration example appearing in the figure, along a line forming in this case the central longitudinal axis of the printed circuit board 2 of the module 1.

[0041] This configuration is however only one possible example, and there may in particular be several lines of light-emitting diodes forming several parallel lighting channels, which can be chained with the channels of other modules after connection.

[0042] The design of the module 1 as it appears in the figure makes it possible to use a single circuit version regardless of the position of the module 1 in the luminaire, in the event that several modules 1 - therefore several printed circuit boards 2 - are assembled axially. In other words, whether the module 1 is located at one end, at the start or end of the chain, or in the middle, among one or more "internal" modules which do not form an end, the electronic circuit itself is identical. Only the connection at the edge of the circuit changes, which is adapted to the immediate environment of the module 1, that is to say in practice to the nature of the connections, coming from a harness or another module.This does, however, involve slightly differentiating the modules 1 according to their future destination at the time of the installation step (preferably robotic) of the module components or, as mentioned, on the assembly line at the end of the luminaire manufacturing process. The assembly of the connectors on the board is done, as mentioned previously, by surface mounting with reflow soldering on the copper tracks present at each end of the printed circuit board, during the manufacture of the module or during the assembly of the luminaire. The connectors 4 appearing in [Fig.l] are shown schematically and do not necessarily represent precisely the different types of connectors used in practice.

[0043] According to the invention, for a single-module luminaire 1, the two ends of the card 2 are equipped with card-to-wire connectors 4 allowing connection to the harnesses comprising 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 board-to-board connectors and the free ends are equipped with 4 board-to-wire connectors allowing connection to the power cables of the luminaire, which is in this case bimodule. By further increasing the size of the luminaire, that is to say in the hypothesis of a luminaire with 3 PCBs or more, at least one intermediate module 1 is added, comprising in this case 4 board-to-board connectors at its 2 ends.

[0044] With reference to [Fig.2], a module 1 consists of a support 5 preferably made of aluminum, on a first face of which is placed the printed circuit board 2 provided with its diodes 3 (see in [Fig.3]), covered with a translucent cover 6 and the end of which comprises a connector 4. The axial end of the module 1 comprises a flange composed of a flexible sealing insert 7 and a rigid cap 8 fitted into each other. A harness 9 comprising at least one power cable is connected to the connector 4, the cable being fixed in a solid manner 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 fixing means ensuring the exercise of axial pressure against said end, the flexible insert 7 then ensuring sealing with the axial end of the support 5 and the cover 6.A seal is similarly arranged with the flexible cable of the harness 9, the insert being tightened around said cable at the level of the hole made there to allow the cable to pass through.

[0045] 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 secured to a fixed wall of a controlled atmosphere enclosure for plant production, according to the field of the invention.

[0046] A heat sink 20 for liquid cooling, the attachment of which to the support is specified in [Fig.7], is shown in [Fig.2], with its hydraulic connections

[0047] 21 end and its inner conduit 22. This is optional equipment, the module 1 shown being able to operate without this addition, with dissipation of the calories in the ambient air around the module 1, as shown assembled in figures 3 and 4. The aluminum profile of the heat sink 20 for liquid cooling, when mounted, forms a unit with the rest of the module 1 (see in [Fig.5]).

[0048] This profile can take an alternative form for the additional fixing of a second module 1', and consequently used as a connecting profile 20' of this other module 1', in the manner shown in [Fig.6]. This configuration, in particular used vertically, can be installed for example between rows of tomatoes, in an enclosure configured for this purpose.

[0049] The transverse profile of the support profiles 5, of the dissipator 20 and of the attachment 20' appears in [Fig.7]: the attachment means 25 present on the support 5 are consisting of recesses in the form of axial grooves made in the face of the support 5 oriented opposite the face receiving the printed circuit board 2. These axial grooves run along the entire length of said face. Their profile matches the external profile of reliefs 26 formed in the form of ribs, so as to achieve a tight fit in these counterformed configurations, then possibly fixed to each other. The module 1 (on the left of [Fig.7]) can therefore become a compact cooler module when a profile 20 is fixed to it (in the center of [Fig.7]) and a double compact module 1,1' by fixing between two modules 1 and 1' a connecting profile 20' (on the right of [Fig.7]). The latter can also include an orifice 22 for the passage of liquid and consequently also serve as a heat sink for liquid cooling.

[0050] The hood can also take several forms, as shown in [Fig.8], in which three versions are shown, each time with a simulation of the trajectory of 4 light rays. On the left, the inner face of the hood 6 is smooth, like the outer face, which remains so in the three configurations shown. In the center and on the right, slightly different indentations are implemented 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.

[0051] [Fig.9] shows a very simplified diagram of a hydraulic heat recovery circuit, in the case of the use of heat sinks 20, 20' for liquid cooling. The "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 other customer processes, the heat being much easier to channel into a heat transfer fluid while it is difficult to manage its convection in the ambient air. It is also possible to dissipate this heat almost free of charge all year round, by evacuating it to the outside via an air cooler or a geothermal installation, rather than using a refrigeration device consuming electricity to generate the cooling.

[0052] 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, etc.), a length which allows the luminaire to be correctly adapted to the standard dimensions of hydroponic cultivation systems.

[0053] One of the major advantages of using LED technologies is the vast possibilities for electronic control of LED luminaires, via LED controllers often referred to as “LED drivers”, which are an essential element Lighting systems using light-emitting diodes. In practice, they allow the power supplied to the LEDs to be regulated in order to control their brightness, color, and sometimes even their color temperature, thus allowing them to switch from warm to cool light as needed. The controllers can obviously be programmed for dynamic lighting effects or to follow predefined scenarios, thus fully participating in the management of optimized lighting conditions for each plant production application in a controlled environment.

[0054] The configuration example which is the subject of the figure should not be considered as exhaustive of the invention, which includes variants, for example in the arrangement of the components installed on the printed circuit board 2 - such as for example the addition of other diode channels 3 to form from 1 to n channels or luminaires which can be chained in series or in parallel - or even the shapes of the different components of the system.

Claims

Claims

1. Luminaire with light-emitting diodes (3) of the LED type, characterized in that it consists of at least: • a module (1) comprising: - a support (5) consisting of a rigid profile; - a printed circuit board (2) fixed on 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) secured 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 board 1.printed circuit board and fixed to the rigid support (5); - attachment means (25) to the support (5) consisting of recesses made in a second face of the support (5) oriented opposite the first face supporting the printed circuit board (2); • a harness (9) for connection to a power source, comprising a flexible cable equipped with a connector designed 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 the position of each module (1) in the luminaire, the end connectors (4) of the luminaire being card-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 card-to-wire connectors (4) are of the blade cage type and the card-to-card connectors (4) are of the male pin and female base type. [Claim 4 Luminaire according to one of the preceding claims, characterized in that 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 fixing means ensuring the exercise of axial pressure of the flange against the end of said support (5), and provided with an orifice for the passage of the flexible cable of the harness (9).

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

6. 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.

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

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

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

10. Luminaire according to one of the preceding claims, characterized in that it comprises a profile (20') for attachment 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).

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

12. Luminaire according to one of the preceding claims, characterized in that the rigid profile (5), the profile of the heat sink (20) for liquid cooling and the connecting profile (20') are made of aluminum.

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

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