WO2010076435A1

WO2010076435A1 - Lighting system with electroluminescent diodes

Info

Publication number: WO2010076435A1
Application number: PCT/FR2009/001488
Authority: WO
Inventors: Hervé FINAN; Dominique Navarro; Michel Ben Sadoun
Original assignee: Finan Trading Company
Priority date: 2008-12-31
Filing date: 2009-12-31
Publication date: 2010-07-08
Also published as: FR2940679B1; FR2940679A1

Abstract

The invention relates to a high-power lighting system that uses at least one LED matrix (3) in which the LEDs are arranged into a matrix directly on a substrate machined so as to comprise, on one of the main surfaces thereof, cavities, each of which receiving at least one LED, the substrate proper serving as a cooling element or radiator. The system advantageously includes heat-discharging means and preferably heat-recovering means. The invention can be used for tall lampposts.

Description

LIGHT EMITTING DIODE LIGHTING SYSTEM

FIELD OF THE INVENTION The present invention relates to light-emitting diode (LED, or LED) lighting systems, and in particular to high power lighting systems using LED matrix assemblies. The invention particularly relates to lighting devices comprising such assemblies of LEDs and integrating means for evacuation, heat and advantageously recovery of the heat emitted by the LEDs.

TECHNOLOGICAL BACKGROUND

Luminaires using LED matrix assemblies are known. The major problems that have arisen with these devices are the difficulty to achieve lighting as close as possible to white light or sunlight, the too small diameter of the illuminating area, especially for high-bay luminaires. , and warming of the LEDs and their power circuits, as well as their support, with consequent loss of radiated power and reduced service life.

It is known that LEDs are a very popular alternative to conventional lighting, including incandescent lamps, but also to fluorescent lamps and especially to discharge lamps.

In this context, it has already been proposed for proximity lighting devices, LED arrays to extend the spectrum of the emitted light and to better distribute it on the illuminated surface (see WO 2007/032619, EP 0 921 568, US 5,191,174). It has also been proposed to dissipate the heat emitted by LEDs (see US Pat. No. 7,331,691, WO 2006/123911, WO 2006/099741, WO 02/097884, US 4,729,076 and DE G 93 16 106.9). The lighting power and the reliability of these luminaires are, however, limited on the one hand by the overall power actually emitted by this matrix assembly and, on the other hand, by the need to evacuate the heat emitted by each of the LEDs. Currently known systems are thus limited in their power of illumination, so that they can not be used for example in applications in which the emitted light by the device must be tapping and must provide a beam of illumination as homogeneous as possible and as wide as possible.

However, today we seek to replace conventional high power luminaires with LED luminaires, to face a double challenge, consisting of the need for energy savings and the reduction of maintenance costs. The LEDs must then provide the most uniform and widest possible illumination, while the street lamps equipped must be able to be of great height, in particular for public lighting, such as highway lights, rest areas, etc. highways, airports, stadiums, sports fields, etc., while

LEDs used must have the longest possible life.

SUMMARY OF THE INVENTION

It has now been found that these and other objectives can be achieved with lighting systems according to the invention in which, separately or in combination:

The lighting module is constituted by a set of matrix LEDs, preferably placed and / or glued in unit cells directly arranged in the support matrix; The spectrum and the lighting power of the LEDs are optimized by the use of white-light LEDs, advantageously by mixing LEDs emitting in different colors, or preferably by conversion to phosphorus, especially blue phosphor and / or yellow phosphor , an LED emitting in the blue (see US Patent 7,267,787); • the cooling of the LEDs and / or their support is provided by an original device; and

In an advantageous embodiment, the cooling device further comprises means for collecting and recovering the heat thus removed from the lighting system. By suitably adjusting these various parameters, the skilled person thus achieves the realization of customized lighting systems, such as high-bay luminaires, especially for highways, hypermarkets and their vicinity, airports, etc. , which have previously unknown advantages, and in the alternative that provide an exceptional return on investment, particularly in allowing to valorize the heat a priori harmful, emitted by the lighting modules.

An object of the invention is thus to provide a powerful and reliable lighting system, using at least one LED matrix to replace conventional bulbs, including incandescent, fluorescent or discharge.

Another object of the invention is to provide a powerful lighting system using LED arrays having a high power of distribution, while ensuring the cooling of the system and, optionally, the recovery of the heat thus collected.

These objectives are achieved by means of a light-emitting diode (LED) lighting system in which, alone or in combination:

The LEDs are arranged in a matrix, preferably square or rectangular, but also circular, oval or any other shape, directly on a support machined to define on one of the main faces, cavities intended to receive each at least an LED and whose spacings are advantageously such that frequent interference is avoided or substantially avoided in this type of assembly, while said support is itself made of metal, such as for example copper;

• the LEDs are fixed on the bottom and / or the wall of the said cavities in places adjusted to be able to optionally orient the beam of the concerned LED, while the geometry of the cavity can be adapted to provide the beam of the concerned LED a greater or lesser concentration, as needed;

Said machined metal support itself acts as a cooling element or radiator, said radiator constituting a cooling system of passive or active type with coolant circulation;

The system is equipped with means of heat evacuation, in particular of the radiator type, themselves coupled with means forming a collector with fluid passage and / or, optionally, with means of cooling with phase change, advantageously in close thermal relationship with said radiator; and

• optionally, a heat pump type device for recovering all or part of the calories emitted by said lighting system. Alternatively, the cooling module may comprise a thermosiphon, in addition to or instead of the micropump-radiator assembly.

In a preferred embodiment, the LED lighting system according to the invention is arranged to constitute a bulb substitutable for incandescent or fluorescent bulbs, and especially conventional discharge lamps. In this embodiment, the cooling system advantageously comprises, optionally, a micropump connected on the one hand to the rear face of the LED support, against which said micropump or any equivalent device, active or passive, is able to circulate a suitable heat transfer fluid, and secondly to a radiator for the evacuation of the heat thus collected.

Said micropump-radiator or said thermosiphon assembly can be integrated at the rear of the support or platen supporting the LEDs, or alternatively it can be placed on or in the vicinity of the mast of a lamp with at least one lighting system. LED according to the invention, preferably in a vertical position ascending or assimilated.

In one aspect, the LED lighting system according to the invention thus comprises an LED support provided with cavities intended to receive each at least one LED, while the bottom of said cavities is provided, on the inner face on which the LEDs are fixed, a reflective coating, including metal Ag, with protection against oxidation, and / or Ni / Cr.

In practice, the skilled person then adapts the size and shape of the cavities to the needs he is confronted with. This makes it possible to obtain an LED lighting system suitable for a specific case, or to obtain a variety of LED lighting systems in which one can choose, on a case-by-case basis, a perfectly appropriate system, in particular by the geometry of its beam, the radiated power, advantageously with concentration, so as to provide a lighting system suitable for high lighting.

The unitary cavity in which one or more LEDs are introduced into selected positions according to the invention provides in effect an original means for avoiding or attenuating interference phenomena between adjacent LEDs, to allow orientation with respect to each other, if desired, and / or to concentrate / disperse the beams of several LEDs close, with the effect of an optimal distribution of the overall beam, with less shadow effects and / or over-lighting in the overlapping areas of the individual beams, and with optimal management of the radiated light power. The invention also relates to complete lighting devices comprising such LED assemblies and incorporating means for heat dissipation and advantageously for recovering the heat emitted by the LEDs, as well as a support structure, such as a mast.

The system according to the invention as described above makes it possible to achieve on all occasions lighting meeting the criteria of quality and reliability required, while providing savings at the various levels mentioned above.

Other objects of the invention will become apparent on reading the following description and the accompanying drawings, in which the embodiments described are provided solely for illustrative purposes, and in no way limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the appended drawing plates, in which:

Fig. 1 represents a perspective view of an outdoor lamp post pole head, provided with a reflector incorporating an LED matrix, itself connected to an external radiator.

Fig. 2a is a partial schematic cross sectional view of an LED wafer, showing three LEDs fixed in respective cavities machined according to asymmetric profiles. Fig. 2b illustrates the contours of the three lighting zones obtained in a plane perpendicular to the mean plane of the LEDs, and about 6 m away from them.

Fig. 3a illustrates, in perspective, a device constituting a radiator of the heat transfer fluid type, in the open position. Fig. 3b shows the same system on the active side of which is directly applied and fixed a LED plate., Whose illuminating face is directed outwards.

Fig. 4 is a diagrammatic representation in elevation of a set of LED modules connected to an external radiator. Fig. 5 is a diagram illustrating the integration of a heat recovery system collected on an LED module in a domestic or industrial heating circuit.

Fig. 6 illustrates in side view and partial longitudinal section a plate of an LED module combined with a pump. and provided at one end with a base for its integration in a screw socket, in particular E27 or E40, a luminaire.

DETAILED DESCRIPTION OF THE INVENTION The invention aims at a high power LED lighting system, in particular but not exclusively for a vertical or substantially vertical mast luminaire.

For simplicity, the invention is described below with reference to such a mast, but without this being limiting. The skilled person is able, on the basis of his knowledge and the present indications, to transpose the indications provided here to other applications using LED matrices.

As shown in FIG. 1, the mast 1 of a straight street lamp comprises a head 2 in which can be housed a matrix of LED 3 or the plate provided with a cap E40 or E27 (Figure 6). The rear face thereof is connected by a pipe or pipe, flexible and / or rigid, to a heat evaporator having the configuration of a radiator 4.

Advantageously, the LED module consists of a square or rectangular matrix of a large number of LEDs arranged in a conventional manner for LEDs "chip". According to an advantageous variant, this LED module may further comprise a cover optics and / or a collimator, and at least a portion of the LEDs are integrated into recesses machined in the support module. The assembly is naturally complemented by wiring, connections and connections, as well as insulators, and optionally at least a phosphorus salt and a resin, traditional for this type of product.

As shown in FIG. 2a, the arrangement of the LEDs 5 in the cavities 6 may be asymmetrical. Such a system can give (see Fig. 2b) illumination along zones 7, 7 ', 7 "in partial overlap on a surface perpendicular to the mean plane of the LED module and at a distance from it. In another aspect, the LED module may also include an optical covering device, comprising a plastic element (especially PMMA) forming collimator, designed to absorb at best only about 9% of the light, while said collimator is essentially to reduce glare and / or control the angle of diffusion of lighting.

All or part of the cavities 6 may, if desired, be coated by means of a suitable reflective surface treatment (for example for depositing Cr, Ag, etc.). In the embodiment shown in FIG. 2a, the cavities of the LED support in which at least a portion of the LEDs constituting the module are placed are suitably machined to have a symmetrical or asymmetrical transverse profile, so as to thereby provide a respectively symmetrical or asymmetric illumination beam , depending on what you want. In practice, only a portion of said cavities may optionally have such an asymmetric cross section. Thus, the simple exchange of one LED module by another having a different configuration makes it possible to very easily and cheaply modify the lighting characteristics of a lamp, whose constituent elements and the other functional elements can then remain unchanged. which is an undeniable economic advantage.

As illustrated in Figs. 3a and 3b, the support 8 comprising at least one die 9 of cavities lined with LEDs can be applied directly to the active face 10, of metal such as for example copper, of a conventional heat sink device 11, also called a system cooler, active type (fluid circulation such as: air, water, oil, etc.), or advantageously passive. The collector system (Cu, Al, etc.) captures by its outer face most of the heat generated by the LED module 9 in operation. According to the variant embodiment shown in FIG.

4, the collecting device 11 is advantageously coupled to at least one radiator 13, by means of one or more suitable flexible or rigid conduits.

Such a system with collector and radiator allows a very precise control of the temperatures and an excellent control of the functioning of the LED modules connected to it. It can then operate in the range of ambient or low temperatures. However, such heat transfer has a positive impact on the illumination of the LEDs and on the lifetime of the latter.

Alternatively, particularly for applications with high power lighting, it is also conceivable to provide the LED modules with at least one transfer / heat collection system operating by thermosiphon or phase change, which then allows operation at temperatures below zero, if desired in particular applications. Referring now to the alternative embodiment shown in FIG. 5, the device as shown in FIG. 4 opens out, not on a radiator 13, but on a thermal energy recovery system, including the conventional heat pump type 14. Such a system can thus feed a residential heating circuit, or industrial premises or offices, instead of allowing the heat collected to disperse into the environment,

In the variant of the LED lighting system according to the invention illustrated in FIG. 6, there is provided an LED lighting module 15 constituting a bulb 16 with a base 17, and provided on its rear face with a radiator 18 radiating in a micropump 19 to discharge or a thermosiphon by circulation of water or a another cooling fluid, or in fluid communication with a larger external radiator, advantageously located on or around the upper end of the pole of the lamp concerned. To facilitate the attachment and replacement of such an LED matrix bulb in said luminaire head, it is advantageous that the bulb 16 has a screw base, or even a rotating base to allow to screw the base 17 on the supply bushing without rotating the bulb and / or the luminaire head, which can thus maintain their preferred orientation relative to the chosen plane, in practice a substantially horizontal plane, for optimized lighting.

In advantageous embodiments of the various aspects of the invention as described above, one or other of the following provisions / terms may be used, separately or in combination: the power supply and / or the electronics of the system according to the invention are reported in the lower part of the lamppost, that is to say in practice at ground level or at man's height, in order to facilitate the interventions, including control, adjustment and troubleshooting; the system uses phosphorus (according to a technique known to those skilled in the art and preferably as described in US Pat. No. 7,267,787), but integrated, in practice in the form of phosphorus on a silicate base and / or aluminate, in the collimator and / or on the inner face thereof; the heat dissipation of the LED module can be effected by thermosiphon, without pump; the geometry of the reflector of the luminaire is such that the evacuation of the heat received by it, for example under the effect of sunshine, is facilitated; the reflector of the luminaire is configured to release passive ventilation on its underside, between the latter and the LED module, in order to optimize the evacuation of the heat emitted by the LEDs as well as that resulting from the heating of the reflector of the luminaire due to sunshine; the heat collector means may be in close thermal relationship with at least one fan, preferably fixed to a tall lamp structure, particularly for public, industrial and / or storage buildings; the LED matrix comprises a set of approximately 30 to 400 LEDs according to the desired power, advantageously around 100 LEDs, arranged in a substantially rectangular matrix comprising 3-20 lines and 10-20 columns; the support of the LEDs comprises the wiring and connections required, advantageously in the form of printed circuit boards, hybrid or nanometric.

Those skilled in the art will readily understand that the practice of the present invention provides undeniable advantages and significant progress over currently known and practiced techniques. Thus, it is possible to achieve substantial savings and simplify the on-site intervention procedures with the technique according to the invention.

In particular, the LED lighting system according to the invention can be applied to the production of high-rise and / or high-power luminaires operating at voltages that can be practically 12-24 volts to 240 volts, and providing a luminous flux of approximately 10,000-19,000 lumens, ie more than 100 Im / W.

Claims

1. High power lighting system using at least one LED matrix, characterized in that the LEDs (5) are arranged in a matrix directly on a support (8) machined to comprise, on one of the main faces of the cavities (6) intended to each receive at least one LED (5), while the arrangement of the LEDs (5) in two adjacent cavities (6) is asymmetrical, and / or at least a part of said cavities present an asymmetric transverse profile, and while said support itself serves as a cooling element or radiator (13).

2. Lighting system according to claim 1, characterized in that it comprises a collimator in which and / or on the inner face of which is integrated phosphorus.

3. Lighting system according to claim 1, characterized in that said radiator constitutes a cooling system of passive or active type circulating heat transfer fluid.

4. Lighting system according to claim 1, characterized in that said radiator is coupled with fluid passage heat collector means and / or, optionally, with phase change cooling means.

5. Lighting system according to claim 4, characterized in that the heat collector means are in close thermal relationship with said radiator.

6. Lighting system according to claim 5, characterized in that it further comprises a heat pump type device.

7. Lighting system according to one of claims 5 or 6, characterized in that it further comprises a thermosiphon.

8. Lighting system according to claim 1, characterized in that it is arranged in a bulb with base (16) incorporating at least one LED matrix (3), said bulb comprising a cooling system comprising a thermosiphon, connected to a radiator.

9. Lighting system according to claim 1, characterized in that it is arranged in a bulb with base (16) incorporating at least one LED matrix (3), said bulb comprising a cooling system comprising a micropump, connected to a radiator.

10. Lighting system according to any one of claims 1 to 9, characterized in that it is combined with a pole lamp post (1), preferably a mast of high street lamp.

11. Lighting system according to claim 10, characterized in that the micropump-radiator assembly and / or the thermosiphon is fixed on the mast of said lamp post.

12. Lighting system according to any one of claims 1 to 4, characterized in that the heat collector means are in close thermal relationship with at least one fan, preferably fixed on a structure forming a high street lamp, especially for public, industrial and / or storage buildings.