The present invention relates to a LED lighting device of the type described in the preamble of Claim 1.

There are currently known LEDs (acronym for light emitting diode) recently used to light various spaces, such as: domestic spaces, offices, open spaces such as squares and gardens and the like.

LED lighting devices have various advantages with respect to more conventional lighting devices, such as incandescent lamps and fluorescent lamps.

In particular, LEDs have a very small volume, even less than one cm³, very high efficiency, produce a light that can obtain a desired colour, switch on very quickly when energized by electrical current and so forth.

As well as said advantages, LED lighting devices also have some considerable drawbacks.

In fact, having powers of over one Watt, LED lighting devices can become very hot due to their small volume.

This heating can cause rapid deterioration of the chip associated with this LED and thus deterioration of the LED, which decreases in efficiency and other features.

In this situation the technical aim of the present invention is to devise a LED lighting device capable of substantially overcoming the aforesaid drawbacks.

Within said technical aim an important object of the invention is to achieve a support structure for LED lighting devices which allows optimum heat dissipation. Some support structure, not able to completely overcome the said drawbacks, is described in patent applications: WO-A-2007/143991, JP-A-2004-296245, US-A-2003/224687, US-A-2004/156199, US-A-2009/040776 and US-A-7434964.

Another important object of the invention is to produce a simple and inexpensive LED lighting device.

The technical aim and the objects specified are achieved by a LED lighting device as claimed in the appended claim 1.

Preferred embodiments are highlighted in the dependent claims.

Other characteristics and advantages of the invention are further elucidated in the following detailed description of a preferred embodiment of the invention, with reference to the accompanying drawings, wherein:

• Fig. 1 shows a overall top view of the support structure according to the invention and an enlargement of a detail;
• Fig. 2 shows a side view of a detail of the support structure;
• Fig. 3 shows the normal section III-III, indicated in Fig. 1, of the support structure; and
• Fig. 4 shows the normal section IV-IV, indicated in Fig. 1, of the support structure.

With reference to the Figures, the support structure according to the invention is indicated as a whole with the number 1.

It comprises a rod 2 and support means 3, suitable to support at least one LED 4.

Several LEDs 4 can also be provided for a single rod 2.

The rod 2 is circular and hollow and has an outer surface with a normal section preferably substantially circular. It is made a metal material with high thermal conductivity, such as in particular: copper, aluminium, silver, gold or their alloys and more preferably copper alloy nickel plated on the surface.

The rod 2 then comprises an internal hollow 2a also circular and conveniently coaxial with the outer surface (Fig. 3).

The hollow rod 2 also preferably has an external diameter of between 2 mm and 6 mm, and preferably between 2 mm and 4 mm, and a diameter of the internal hollow 2a preferably of between 1 mm and 3 mm. Moreover, it conveniently has a length exceeding 5 cm and more preferably exceeding 10 cm and a maximum length variable to even more than 2 m.

The support means 3 is also at least partly integral and in one piece with the rod 2.

It comprises support surface 3a, suitable to support, preferably through interposing of a further element better defined below, at least one LED 4 and preferably only one LED 4.

The support surface 3a is realized by a flattened portion of the rod 2.

For example, it can be at least partly produced by partial flattening of the rod 2. In this way any discontinuity of the material, which would realize a thermal resistance, is avoided.

In particular, a flattening along only one portion of the rod 2 is preferred. This flattening therefore defines a substantially flat support surface 3 which, in the normal section (Fig. 4), essentially realizes a chord of the circumference defined by the outer surface of the rod 2.

Moreover, as this is a plastic deformation, the entire portion of rod 2 corresponding to the support surface 3a will be deformed by said flattening, as shown in a simplified manner in Fig. 4.

Finally, said flattening will achieve a reduction of section, visible in Fig. 2, preferably of between 10% and 50%.

The support structure 3a preferably has a base with a width close to the diameter of the rod 2 and conveniently of between 2 mm and 6 mm, and a length preferably of between 1 cm and 5 cm and more preferably between 2 cm and 3 cm.

Moreover, an opening 3b is provided in proximity of an end of the support surface 3a, to place the inner hollow 2a of the rod 2 in communication with the outer surface. It is conveniently substantially circular with a diameter close to the diameter of the rod 2.

Moreover, the support means 3 is preferably not produced at an end 2b of the rod 2, but at a distance of over 5 mm from this end 2b, as shown in Fig. 1.

This solution allows dissipation of heat along both sides in the direction of extension of the rod 2.

The end 2b of the rod 2, close to the support means 3, therefore conveniently has an annular circular and open shape and, conveniently, also the end 2c further from the support means 3 has an annular circular and open shape so as to allow the passage of air inside the hollow 2a.

The support means 3 also comprises a plate 8 made of a material with high thermal conductivity, as specified above and more in particular of aluminium alloy.

The plate 8 is fixed directly to the support surface 3a and preferably has base dimensions similar to those of this support surface 3a, or between 3 and 5 mm and between 2 and 3 cm, and a height preferably between 0.5 and 2 mm.

It is conveniently fixed to the support surface 3a by means of releasable mechanical connections, such as two screws 11 disposed in proximity of the ends of the plate 8.

This solution makes it possible to avoid the presence of glues, which could reduce heat transmission between the plate 8 and the rod 2.

Moreover, elements such as conductive pastes and the like can be present between plate 8 and support surface 3a or alternatively a conductive weld or double-sided adhesive tape could be provided.

The plate 8 is therefore conveniently the portion of the support means 3 suitable to support the LED 4.

The LED 4 is realized by a printed circuit 4a and a bulb, or primary lens, 4b.

The printed circuit 4a is conveniently substantially rectangular and has base dimensions of between 1 mm and 5 mm.

The bulb 4b is made of polymer or silicone material or glass and preferably has an external diameter of between 0.3 mm and 3 mm and more preferably between 1.5 mm and 2 mm. Moreover, it has a substantially semi-spherical shape.

The LED 4 has a power of between 0.1 W and 50 W and more preferably between 0.5 W and 30 W.

It is known per se and realized, for example, by the LED known with the trade name PHILIPS LUMILED LUXEON Rebel.

The LED 4 is also connected to an electrical power source through electrical connections 5 suitable to supply power to this LED 4.

It comprises at least one conductor wire 6, and preferably two, covered with a sheath, or braid, 7 made of polymer material and preferably polyester, or alternatively, not covered.

The conductor wires 6 are disposed at least partly inside the rod 2 and, in proximity of the opening 3b, have no sheath 7.

These conductor wires 6 without the sheath 7 then pass through the opening 3b and connect, mechanically and electrically, to at least one clamping element 9. Preferably, two clamping elements 9 are present, one for each wire 6, disposed on the plate 8 and realized by welds suitable to support and clamp these wires 6.

The clamping elements 9 also connect the wires 6 of at least one connection element 10.

The connection elements 10, also preferably two in number, are connected directly to the LED 4 and preferably realized by two electrical connections in conductive material realized by two flat elements, as shown in Fig. 1.

The plate 8, including the connection elements 10 conveniently disposed on the surface, is finally preferably coated with white paint along the outer surface. The support structure 1 according to the invention achieves important advantages.

In fact, due to the particular shape, this structure 1 allows optimum heat dispersion through the rod 2, which allows the LED 4 always to be maintained at optimum temperatures so as to prevent deterioration or overheating thereof.

The heat is dispersed in particular by the hollow and annular shape of the rod 2 and by the material with high thermal conductivity.

In particular, the heat is diffused on both sides of the rod 2, due to the fact that the support means 3 are positioned at one end of the rod 2.

Moreover, the structure of the rod 2 allows air to circulate inside the hollow 2a, as the ends 2b and 2c are not closed, and the creation of convective move.

Moreover, the structure of the rod 2 allows air to circulate inside the hollow 2a, as the ends 2b and 2c are not closed, and the creation of convective movements which allow superior cooling of the LED 2.

Furthermore, the structure 1 is easily deformable in an axial direction and therefore allows the rod 2 to be shaped as required.

Yet another advantage is given by the fact that the structure 1 does not have exposed cables which can give the structure an unsightly appearance.

The invention is susceptible to modifications and variants falling within the scope of the claims.