FR2981731A1 - LIGHT EMITTING DEVICE LIGHTING DEVICE - Google Patents

Abstract

Light-emitting diode (1) lighting device equipped with a heat dissipator comprising a radiator characterized in that said heat dissipator comprises: a base body (4), one of the body faces base (4), said lighting face supporting said light-emitting diodes, said lighting face being intended to be directed downwards, the other face of the base body (4), said transmission face (7) of heat being in contact with the radiator (3), - the radiator (3) constituted by a monoblock element comprising: - a plate (31), one of the faces of the plate being in contact with said transmission face (7) of the base body (4) - fins (32) extending around said plate (31), said fins (32) being oriented substantially perpendicular to said plate (31) so as to allow cooling of the diodes electroluminescent by natural convection.

Description

The invention relates to a lighting device with light emitting diodes equipped with a heat sink, and will find a particular application as a lighting head for street lamp. The field of the invention is that of public lighting devices, such as street lights or the like. In the field of public lighting, there are known lighting heads comprising a lampshade, equipped with light-emitting diode arrays and a heat sink for evacuating the heat generated by said diodes.

For example, document EP2189 709A1 discloses a lighting device with light-emitting diodes, more particularly a lamp post, comprising a heat sink. This shade comprises an upper plate and a lower plate shaped and assembled together so as to form a hollow body internally receiving light emitting diode rails. The sheets are provided with perforations so as to form a blind, breathable, constituting a heat sink. The heating of this lampshade makes it possible to create, by convention phenomena, a flow of air ensuring the cooling of the electroluminescent diodes. Other lighting devices with light-emitting diodes, each equipped with a heat sink, are known from the state of the art, such as for example, those of documents WO2010 / 119146A1 or WO2009 / 157662A2. The object of the present invention is to provide a light emitting diode lighting device equipped with a heat sink, and whose cooling performance is improved. Another object of the present invention is to propose such a lighting device incorporating the part of electronics necessary for powering, or even controlling, the electroluminescent diodes.

Another object of the present invention is to provide such a lighting device of simplified design, minimizing the number of parts required for its manufacture. Another object of the present invention is to provide such a lighting device requiring little maintenance. Other purposes and advantages will become apparent from the following description which is given for information only and which is not intended to limit it. The invention relates to a light-emitting diode lighting device equipped with a heat dissipator comprising a radiator. According to the invention, the heat dissipator comprises: a base body, one of the faces of the base body, said lighting face supporting said light-emitting diodes, said lighting face being intended to be directed towards the bottom, the other face of the base body, said heat transmission face being in contact with the radiator, - the radiator constituted by a monobloc element comprising: - a plate, one of the faces of the plate being in contact with said heat transmitting face of the disk, - fins extending around said plate, said fins being oriented substantially perpendicular to said plate, so as to allow the cooling of the light emitting diodes by natural convection. According to one embodiment of the invention: the base body has a chamfer on its circumference between said transmission face and the edge of the base body; the face of the radiator plate in contact with said transmission face; heat has a shape-complementary cavity to that of the base body, with a flat surface in contact with the heat-transmitting face and a bevelled portion in contact with the chamfer.

According to optional features of the invention, taken singly or in combination: - said face of the radiator plate in contact with the heat-transmitting face is said lower face, walls of said monobloc element extending projecting from the another face of the plate, said upper face, said walls being oriented substantially perpendicular to said plate, said fins being secured by their inner edge of said walls; - The device has a feed group, said walls of said monobloc member forming a housing, in particular of rectangular shape, inside which is received the feed group; - The power unit is received in a housing positioned in said housing so as to create a blade of air between the interior of the housing and the housing of the power unit, said plate of said radiator having vents orifices in such a way as to allow the circulation of said air gap by natural convection; said radiator is said first radiator, the power unit comprising a second radiator, distinct from said first radiator, said second radiator being constituted by a monobloc element provided with fins, in particular provided in the extension of the fins of said first radiator; - The device has an optical arranged in line with said light emitting diodes and wherein the face of the dissipator plate in contact with the heat transmission face has a shoulder dimensioned for the reception of the optics; - The optics is maintained in the shoulder by means of a removable ring, an eyelash seal allowing the flow of rain water on the surface of the optics; the lighting face of the base body supporting said light-emitting diodes comprises a middle part and, on either side, two projecting lateral parts, said middle part supporting blue-light-emitting diodes embedded in a phosphorized gel, the gel being received in the cavity formed between said two lateral parts, the lateral parts receiving other light-emitting diodes; the base body is in a copper-based metal and said monoblock element of the aluminum dissipator, a silver-based coating, less than 100 microns thick, facilitating heat transfer between the base body and said monoblock element; the length of the fins in said direction substantially perpendicular to the plate is greater than one-third of the smallest dimension of the base body, in a direction parallel to said plate. The invention also relates to a lamp post equipped with a lighting device according to the invention, said lighting face being directed downwards. The invention will be better understood on reading the following description accompanied by the appended figures in which: FIG. 1 is a perspective view of a lighting device according to the invention according to one embodiment. FIG. 2 is a sectional view of the device as illustrated in FIG. 1. FIG. 3 is an exploded view of the device as shown in FIG. 1. FIG. 4 is a sectional view. Figure 5 is a detail view of the diode matrix supported by the base body. FIG. 6 is a sectional view of the matrix as illustrated in FIG. 5. FIG. 7 is a view illustrating the particular relief of the illumination face of the base body. FIG. 8 is a perspective view from above of a lighting device, according to a second embodiment of the invention, of rectangular shape; FIG. 9 is a bottom view of the device of FIG. 8; Also, the invention relates to a lighting device 1 with light-emitting diodes 2 equipped with a heat dissipator comprising a heat sink 3 and whose function is to ensure the cooling of said light-emitting diodes 2. According to the invention said dissipator of thermal energy comprises: - a base body 4, one of the faces of the base body 4, said lighting face 6 supporting said light-emitting diodes 2, said lighting face 6 being intended to be directed downwards the other face of the base body 4, said heat transfer face 7 being in contact with the radiator 3, - said radiator 3 constituted by a monobloc element 30 comprising: - a plate 31, one of the faces of the plate was in contact with said heat transfer face 7 of the disk 5, - fins 32 extending around said plate 31, where appropriate, radially and regularly distributed around the axis A of the base body 4, said fins 31 being oriented substantially perpendicular to said plate 31 so as to allow the cooling of the light emitting diodes 2 by natural convection. Preferably, the base body 4 is in a copper-based metal and said monobloc element 30 of the aluminum radiator 3. Advantageously, a coating based on silver, with a thickness of less than 100 microns, especially between 10 and 70 microns (ie 30 microns) can be provided between the radiator 3 and the base body to facilitate the transfer of heat between these two elements. Similarly, the light-emitting diodes may be secured (ie soldered) to the illumination face 6 of the disc 5 via a silver-based coating, less than 100 microns thick, in particular between 10 and 70 microns (ie 30 microns). In such a system, the heat generated by the light-emitting diodes is transmitted to the base body 4, then to the radiator 3.

The heating of the radiator 3 creates a temperature gradient promoting the air circulation between the fins 32, by natural convection. According to the example of Figures 1 to 7, the base body 4 takes the general shape of a disk 5. However, many other forms are possible for the base body 4 such as for example a thin body of cane shape, star or other ... Moreover, the fins 32 are, according to the examples illustrated in the figures, directed along their length strictly perpendicular to the plane of the plate 31.

These fins may however not be strictly perpendicular to the plane of the plate 31, but have a slight inclination with the perpendicular, and in particular an inclination relative to the perpendicular between 0 ° and 15 °. Furthermore, according to the example of Figures 1 to 6, the fins 32 are angularly distributed regularly around the axis A of the disc 5, directed in radial directions. Other arrangements of the fins 32 are possible, however, the fins being parallel to each other, in sections, around said plate 31. According to an advantageous embodiment, illustrated more particularly in FIGS. 4 and 6: the base body 4 ( in particular the disk 5) has a chamfer 50 on its circumference between said heat transfer face 7 and the edge of the base body 4, the face of the plate 31 of the radiator 3 in contact with the heat transfer face 7 present a cavity 33 of complementary shape to that of the base body 4, in particular of the disk 5, with a flat surface 34 in contact with the heat transfer face 7 and a beveled portion 35 in contact with the surface of the chamfer 50. Such that illustrated in the example of Figures 1 to 6 for which the base body 4 is a disc 5, this beveled portion 35 is frustoconical. In the case of a square base body, this beveled portion would affect a truncated pyramid shape. Such an assembly makes it possible in particular to increase the exchange surfaces between the base body 4 and the radiator 3, and generally to improve the performance of the heat sink. Moreover, the inventor has found good cooling performance when the length of the fins 32 in said direction substantially perpendicular to the plate 31 is greater than one-third of the smallest dimension of the base body 4, in a direction parallel to said plate 31 .

For example in the example illustrated in Figures 1 to 6, this results in a fin length 32, in the direction of height, greater than one-third (1/3) of the diameter of the disk 5. According to the illustrated examples, the monobloc element 30 of the radiator 3 constitutes an air-permeable shade.

According to one embodiment, said face of the radiator plate 3 in contact with the heat transfer face 7 is said lower face, walls 36 of said one-piece element 30 extending from the other face of the plate 31, so-called upper face, said walls 36 being oriented perpendicularly to the plane of said plate 31, said fins 32 being secured by their inner edge of said walls 36. According to one embodiment, the lighting device comprises a feed unit 8 comprising the electronics necessary for the power supply, or even the control of the diodes. According to the embodiment of FIG. 4, said walls 36 of said one-piece element 30 form a housing 9, in particular of rectangular shape (seen from above); inside which is received the power unit 8. Preferably, the power supply unit 8 is received in a housing 80, of complementary shape to the housing, positioned in said housing 9 in such a way as to create a blade of air 10 between the interior of the housing 9 and the housing 80 of the feed unit 8, and more particularly an air gap between the lower face of the housing 80 and the upper face of the plate 31, and a blade of air between each of the four side walls of the housing 80 and the corresponding wall 36 forming the housing 9.

Advantageously, said plate 31 of said radiator 3 has vent holes 37 so as to allow the circulation of said air knife by natural convection. This circulation of the air space, illustrated by the arrows in FIG. 4, ensures the cooling of the supply unit, but also that of the radiator 3.

According to an embodiment illustrated in Figure 4, said radiator is said first radiator 3, the power unit 8 comprising a second radiator 11, separate from said first radiator 3, said second radiator 11 being constituted by a monobloc element 110 provided with 111. The function of second radiator is to ensure the cooling of the feed group 8; and in particular of its constituent electronic components. According to the embodiment illustrated in the figures, the monobloc element 110 of the radiator 11 also accumulates a cover function to close the upper opening of the housing 80 of said power supply unit 8. A seal 81 makes it possible to seal between the case 80 and this cover.

As illustrated, the fins 111 of the second radiator 11 may be provided in the extension of the fins 32 of said first radiator 3. The one-piece element 110 may be made of aluminum and, in particular is obtained by molding. According to the example illustrated in FIG. 4, the one-piece body 110 has a housing, receiving a connection device 22 between a power supply cable 21 and the power supply unit 8, and capable of providing a class II protection according to FIG. standard NF C 15-100. This connection device 22 comprises a housing 23 in an electrically insulating material (ie plastic) whose upper opening is closed by a cover 24, sealingly via a gasket 25. The bare parts of the electric cables are connected in the internal volume of the housing 23, through an electrical connector. According to one embodiment, the lighting device has an optic 12 arranged in line with said light-emitting diodes 2.

Preferably, the light-emitting diodes 2 are concentrated on the illumination face of the base body so that the end user only distinguishes one light source, and not a plurality of light spots. For this purpose the surface density of the diodes can be from 12 to 20 light emitting diodes per cm 2. Advantageously and in order to limit glare, the average diameter of this optic 12 is greater than four times the average diameter of the emission surface of said illumination face 6 of the basic body. By emission surface of the illumination face 6 is meant the smallest area carrying all the light-emitting diodes 2 of the base body 4. According to the example of the figures, the average diameter of the emission surface is about 28mm and the average diameter of the optics is 127mm.

The face of the plate 31 of the radiator 3 in contact with the heat transmission face may have a shoulder 13, in particular circular, sized for the reception of the optical 12, circular shape corresponding to the interlocking game near. The circular shape advantageously makes it possible to adjust the orientation of the optics and thus the illumination when the optics 12 is asymmetrical optics. The optic 12 is held in the shoulder 13 by means of a ring 14, removable, and a typical system, cooperating with said monobloc element 30. The system is thus scalable and interchangeable.

Advantageously, an eyelash seal 15 allows the flow of rainwater on the surface of the optic 12 to ensure the self-cleaning of the optic 12. This eyelash seal 15 is made of a material elastomer by an integral element having a circular portion 150 intended to be clamped between the optic 12 and said ring 14, and a plurality of eyelashes 151, protruding, regularly distributed over said circular portion 151, resting on the 12 in order to facilitate the flow of water on the optic 12. According to an embodiment illustrated in Figure 7, the illumination face 6 of the base body 4, in particular the disc 5 supporting said light emitting diodes 2 comprises a median portion 16 and, on either side, two side portions 17, 18, projecting. Said middle portion 16 is intended to support light-emitting diodes of blue color embedded in a phosphorized gel 19 received in the cavity formed between said two lateral parts 17, 18.

The lateral parts receive other light-emitting diodes and in particular light-emitting diodes emitting in the visible range (i.e red or amber color) or in the field of non-visible (i.e UV or I.R.). The middle parts 17, 18 are surrounded by a groove 40, generally circular, receiving the interlocking game near a printed circuit 20, allowing in particular the control of the diodes of the matrix row by row. A retaining ring 41 is fixed in particular by means of screws on the lighting face 6 of the disk 5 and makes it possible to keep the printed circuit 20 in the groove 40.

The inner edge 42 (of smaller diameter) of this retaining ring 41 has a shoulder 43 whose inclination makes it possible to retain a layer of gel 46 (silicone) covering the diode matrix 2 and in particular said middle and lateral portions 16, 17, 18, or even a portion of the printed circuit 20. Note that an electrical harness 44 extends from the inside of the housing 80 of the power supply unit 8 to an electrical plug 45 of the printed circuit 20 by the intermediate of a through-hole 38 of the plate 31 of said monoblock element 30. The invention also relates to a lamp post equipped with a lighting device according to the invention, said lighting face being directed downwards. The present application concerns, in addition to the invention, the matrix of diodes, as such, and more particularly, the base body 4, the support face of the light-emitting diodes 2 comprises a middle portion 16, and on both sides , two lateral parts 17, 18, projecting.

As developed, the middle portion 16 is intended to support light-emitting diodes of blue-colored contours embedded in a phosphor gel 19. This gel is received (strictly) in the cavity formed between the two lateral parts 17, 18 and allows modify the emission of the blue diodes in order to obtain light perceived as white.

The middle portions 17, 18 receive on their surface other diodes and in particular light-emitting diodes emitting the visible range (i.e. red or other color) or in the visible range (ie UV or I.R). The diodes of the middle part 16 and that of the lateral parts can advantageously be controlled independently, row by row, by pulse width modulation (PWM). All these parts 16,17,18,19 is covered with a layer of gel 46. The concentration of the diodes of the middle and lateral parts is such that a user perceives only a light source, and not a plurality points. For this purpose the surface density of the diodes can be from 12 to 20 light emitting diodes per cm 2.

The present applicant reserves the right to file a divisional application for this matrix of diodes. Naturally other embodiments of the invention could have been envisaged without departing from the scope of the invention defined by the claims below.

Nomenclature: 1 Light Fixture, 2 Light Emitting Diodes, 3 Radiator 4 Base Body, 5 Disc (Base Body 4), 6 Light Face (Base Body 4), 7 Heat Transfer Face (Basic Body 4), 8 Power Supply Unit, 9 Monobloc Housing (for power supply unit), 10 Air Blade, 11 Second Radiator (power supply), 12 Optic, 13 Shoulder, 14 Bushing, 15 Gasket eyelashes, 16 Middle part (illuminating face 6), 17,18 Side parts (illuminating face 6), 19 Phosphoric gel, 20 PCB, 21 Power supply cable, 22 Connecting device, 23 Housing (device connection 22), 24 cover (connection device 22), seal, monoblock element (radiator 3), 31 plate (monoblock element 30), 32 fins (monoblock element 30), 33 complementary shape cavity (plate), 30 34 Flat surface (cavity 33), 35 beveled portion (cavity 33), 36 wall element (monobloc element 30), 37 outlet openings Winds, 38 Through Hole, 40 PCB, 41 Retaining Ring, 42 Inner Rim, 43 Shoulder, 44 Electrical Harness, 45 Electrical Plug 46 Gel Coat, 50 Chamfer (Basic Body 4), 80 Housing (Power Pack 8) , 81 Gasket, 110 Monobloc element (second heat sink 11) 111 Wings (second heat sink 11).

Claims (12)

REVENDICATIONS1. Light-emitting diode (1) lighting device (2) equipped with a heat dissipator comprising a radiator (3), characterized in that said heat dissipator comprises: a base body (4), one of the faces of the base body (4), said lighting face (6) supporting said light-emitting diodes (2), said lighting face (6) being intended to be directed downwards, the other face of the light-emitting diode (6) base body (4), said transmission face (7) of heat being in contact with the radiator (3), - the radiator (3) constituted by a monobloc element (30) comprising: - a plate (31), one of the faces of the plate being in contact with said heat transmitting face (7) of the base body (4) - fins (32) extending around said plate (31), said fins (32) being oriented substantially perpendicular to said plate (31) so as to allow the cooling of the light-emitting diodes (2) p natural convection. 2. Device according to claim 1, wherein: - the base body (4) has a chamfer (50) on its circumference between said face (7) of heat transmission and the edge of the base body (4), - the face of the plate (31) of the radiator (3) in contact with the heat transfer face (7) has a cavity (33) of a shape complementary to that of the base body (4), with a flat surface (34) ) in contact with the heat transfer face (7) and a beveled portion (35) in contact with the chamfer (50). 3. Device according to claim 1 or 2, wherein said face of the radiator plate in contact with the face (7) of heat transmission is said lower face, walls (36) of said monobloc element (30) extending from the other side of the plate (31), said upper face, said walls (36) being oriented perpendicularly to said plate (31), said fins (32) being secured by the inner edge of said walls (36). 4. Device according to claim 3, having a feed group (8) and wherein said walls (36) of said monobloc element (30) form a housing (9), in particular of rectangular shape inside which is received the feeding group (8). 5. Device according to claim 4, wherein the feed group (8) is received in a housing positioned in said housing (9) so as to create an air gap (10) between the interior of the housing (9). 9) and the housing of the supply unit (8), said plate (31) of said radiator (3) having vents (37) so as to allow the circulation of said air gap (10) by natural convection. 6. Device according to claim 5, wherein said radiator is said first radiator (3), the power unit (8) comprising a second radiator (11), distinct from said first radiator (3), said second radiator (11) being constituted by a monobloc element (110) provided with fins (111), in particular provided in the extension of the fins (32) of said first radiator (3). 7. Device according to one of claims 1 to 6, having an optics arranged in line with said light-emitting diodes (2) and wherein the face of the plate (31) of the dissipator (3) in contact with the heat-transmitting face has a shoulder (13) sized for receiving the optics (12). 8. Device according to claim 7, wherein the optic (12) is held in the shoulder (13) by means of a ring (14) removable, an eyelash seal (15) allowing the flow of rain water on the surface of the optics (12). 9. Device according to one of claims 1 to 8, wherein the illumination face (6) of the base body (4) supporting said light-emitting diodes (2) comprises a middle part (16) and, on the other hand, another, two projecting side portions (17, 18), said middle portion (16) supporting blue-colored light-emitting diodes embedded in a phosphor gel (19) received in the cavity formed between said two side portions (17, 18) , the lateral parts receiving other light-emitting diodes. 10. Device according to one of claims 1 to 9, wherein the base body (4) is in a copper-based metal and said monobloc element (30) of the dissipator (3) aluminum, a coating based on silver, less than 100 microns thick, facilitating the transfer of heat between the base body (4) and said monobloc element (30). 11. Device according to one of claims 1 to 10, wherein the length of the fins (32) in said direction substantially perpendicular to the plate (31) is greater than one-third of the smallest dimension of the base body (4), in a direction parallel to said plate (31). 12. Floor lamp equipped with a lighting device according to one of claims 1 to 11, said lighting face being directed downwards.