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FIELD OF THE INVENTION

[0001] This invention relates to the technical field of LED lighting apparatuses and, in particular, relates to an LED public or street lighting apparatus.

STATE OF THE ART

[0002] In the field of public and street lighting, lighting apparatuses or devices that use semiconductor light sources such as LEDs (Light Emitting Diodes) are being adopted with increasing success.

[0003] The use of LEDs allows producing lighting apparatuses characterised by greater flexibility of use, greater energy efficiency and a higher modularity.

[0004] LED lighting apparatuses generally comprise a plurality of LEDs, equipped with related optics and reflectors, appropriate heat sinks and power supply means suitable to supply the necessary power supply current to the plurality of LEDs.

[0005] In relation to the heat sinks in the state of the prior art, laminar dissipation systems are generally used. An example of a lighting apparatus of the prior art that employs a laminar dissipation system is disclosed by EU registered industrial design No. 002045005-0001. A further example of a lighting apparatus of the prior art that employs a laminar dissipation system is disclosed by European patent application EP2172693. [0006] European patent application EP2746652 describes an LED lighting device, but says nothing about the heat dissipation system with which such a device is provided.

[0007] Although efficient and widely used, the laminar heat dissipation systems of the prior art have the drawback of favouring the accumulation of dirt or dust between the lamellas. A progressive build-up over time can result in a decrease of dissipation efficiency.

[0008] The object of this description is to make available an LED public or street lighting apparatus that solves or reduces, at least partially, the aforesaid drawback .

[0009] This purpose is achieved through an LED public or street lighting apparatus as generally defined in claim 1. Preferred and advantageous embodiments of the aforesaid lighting apparatus are defined in the appended dependent claims.

[0010] The invention will be better understood from the following detailed description of a particular embodiment, provided by way of example and, therefore, in no way limiting, in relation to the accompanying drawings, which are briefly described in the next paragraph .

BRIEF DESCRIPTION OF THE DRAWINGS [0011] Figure 1 is a bottom perspective view of an embodiment of an LED public or street lighting apparatus.

[0012] Figure 2 is a side plan view of the apparatus of Figure 1.

[0013] Figure 3 is a top plan view of the apparatus of Figure 1.

[0014] Figure 4 is a bottom perspective view of the LED pubic or street lighting apparatus of Figure 1 with some parts detached.

[0015] Figure 5 is a perspective view of a first variant embodiment of the apparatus of Figure 1.

[0016] Figure 6 is a perspective view of a second variant embodiment of the apparatus of Figure 1.

DETAILED DESCRIPTION

[0017] With reference to the accompanying figures, the LED public or street lighting apparatus 1 (henceforth referred to, without thereby introducing any limitation, as "LED lighting apparatus") comprises a first container body 2 and at least one array of LEDs 3 housed in the first container body 2.

[0018] In the illustrative and non-limiting embodiment of Figure 1, the lighting apparatus 1 is installed on the top of a vertical support post 20 and is intended for the lighting of urban areas, for example, public areas such as bridges, pedestrian malls, squares, parks and gardens.

[0019] In the example shown, without thereby introducing any limitation, the LED lighting apparatus 1 comprises two arrays of LEDs 3 each arranged on a rectangular or square-shaped matrix. Henceforth, reference will be made to the example shown in the figures in which are provided two arrays of LEDs 3, it being understood that variant embodiments are possible in which is provided a single array of LEDs 3 or more than two arrays of LEDs and that these variant embodiments all fall within the claimed scope of protection.

[0020] According to a preferred embodiment, each of the LEDs of the arrays of LEDs 3 is surmounted or covered by a respective lens of an array of refraction lenses. Preferably, these lenses are injection moulded in polymethyl methacrylate (PMMA) .

[0021] In the installation configuration, and during operation, of the LED lighting apparatus 1, the arrays of LEDs 3 are such as to direct the optical radiation emitted towards the ground of an urban area to be illuminated .

[ 0022 ] According to an embodiment, the first container body 2 comprises one or more housing seats adapted to house the arrays of LEDs 3, for example to house the printed circuit boards that support the arrays of LEDs 3. Said one or more housing seats are watertight, adapted to protect the arrays of LEDs from infiltrations of water, humidity or dust .

[ 0023 ] The aforesaid one or more housing seats are closed by a protective screen 4 that at least frontally to the arrays of LED 3 is made of a material transparent to the optical radiation emitted by the arrays of LEDs 3. Preferably the protective screen 4 comprises a plate of glass or transparent crystal, possibly anti-reflection to reduce the coefficient of attenuation of the luminous radiation passing through.

[ 0024 ] The first container body 2 is made of a thermally conductive material, for example metal, which preferably has a high thermal conductivity. More preferably, the first container body 2 is made of aluminium or an aluminium alloy, and is for example formed in one piece by die-casting.

[ 0025 ] Preferably, the arrays of LEDs 3 are fixed on a support, such as a printed circuit board, fixed to and in contact with an inner wall of the first container body 2, so that it is possible to extract the heat produced by the LEDs and transfer it by conduction to the first container body 2. The extracted heat can thus be advantageously dissipated through the same first container body 2, which thus acts as a passive heat sink.

[ 0026] The first container body 2 is provided with a heat dissipation system comprising an array of through apertures 10 that pass through the first container body 2. Preferably, said through apertures 10 extend between two opposite sides of the first container body 2 crossing the thickness of the first container body 2 laterally in relation to the array of LEDs 3. More preferably, the array of through apertures 10 surrounds the at least one housing seat of the array of LEDs 3. [ 0027 ] Preferably, the through apertures 10 are laterally closed channels made in the thickness of the first container body 2.

[ 0028 ] According to an embodiment, the aforesaid through openings 10 extend inside the first container body 2 each in a respective direction of extension perpendicular to the LED array 3.

[ 0029] According to a preferred embodiment, the array of through apertures 10 extends at least partially along a peripheral outer edge of the first container body 2. [0030] Preferably, the array of through apertures 10 comprises a plurality of through apertures 10 evenly arranged all along the aforesaid peripheral outer edge. So, it is understood how, in this embodiment, the first container body 2 comprises, along an outer peripheral edge, a perforated radiator comprising a plurality of radiant cells constituted by the walls that surround the through apertures 10.

[0031] According to a preferred embodiment, consistent with the example shown in the figures, the first container body 2 is essentially disc-shaped having a disc axis and the through apertures 10 are distributed around the disc axis along a portion of the outer circular rim of the first container body 2 or all along the aforesaid circular rim.

[0032] According to an embodiment, the first container body 2 comprises a central portion 11 of greater thickness and a lateral portion 12 of lesser thickness which surrounds the central portion 11 and the through apertures 10 are placed along the aforesaid lateral portion 12. In the embodiment shown in the figures, the central portion 11 of greater thickness presents a projection of a truncated conical shape or rounded shape in relation to the lateral portion 12 of lesser thickness. According to a possible alternative embodiment, the aforesaid projection has a convex shape, for example in the form of a cap.

[0033] According to a preferred embodiment, the LED lighting apparatus 1 comprises at least one support element 5 of the first container body 2. In the particular example shown in the figures, the aforesaid at least one support element 5 comprises two support arms 5 each having a first end portion 5' fixed to the first container body 2, in the example fixed to an outer edge of the first container body 2. In the embodiment shown, the two support arms 5 are arranged in diametrically opposite positions along a generatrix of a cone.

[0034] The support arms 5 may be of tubular bars or bars with a "U" or "C" profile, so that, inside at least one of them, a channel can be defined suitable to house at least one electrical interconnection element, such as for example at least one unipolar or multipolar conductor provided with insulating sheath.

[0035] According to an embodiment, the LED lighting apparatus 1 comprises a second container body 6 spaced from the first container body 2 through the aforesaid support element, i.e., in the example, by means of the two arms 5. In particular, each of said arms 5 has a second end portion 5", opposite to the first end portion, which is fixed to the second container body 6. [ 0036 ] Preferably, the second container body 6 comprises a base portion 7 having an inner housing compartment accessible via an aperture and a removable cover 8, removably coupleable to the base portion 7 in correspondence of said aperture to occlude the interior and ensure a desired degree of water tightness of the interior compartment. In this embodiment, the aforesaid support element of the first container body 2 is fixed to the removable cover 8. In the particular example shown, the second ends 5 ' ' of the arms 5 are fixed to the cover 8.

[ 0037 ] Preferably, the second container body 6, the removable cover 8 and the arms 5 are made of metal, for example aluminium. [ 0038 ] According to an embodiment, the second container body 6 has the shape of a truncated cone and the cover 8 is a disk that represents the larger base of the truncated cone.

[ 0039 ] According to an embodiment, inside the second container body 6, the LED lighting apparatus 1 comprises a driver module of the arrays of LEDs 3, i.e., an electric module adapted to supply the arrays of LEDs a driving current required for operation of the LEDs 3. According to an embodiment, the electrical interconnection between the driver module and the arrays of LED 3 is realised by means of electrical interconnection elements and, for example, one or more cables, which extend from the second container body 6 to the first container body 2 passing inside the at least one support element 5.

[0040] According to an embodiment, the second container body 6 comprises at least one attachment element 16 adapted to secure the second container body 7 and therefore the whole entire LED lighting apparatus 1 to a support device. For example, with reference to Figure 4, the second container body 7 comprises an engagement seat inside of which can be engaged the head of a vertical post 20 as shown in Figure 1.

[0041] According to a further embodiment, the support element, for example the arms 5, and the first container body 2 are mutually detachably coupled so that it is possible to fix the first container body 2 to the support element, for example to the two arms 5, so as to turn the arrays of LEDs 3 toward the second container body 7 or in the opposite direction.

[0042] In the particular example shown, one can see that, in Figure 1, the arrays of LEDs 3 are oriented towards the second container body 6 and the LED lighting apparatus 1 is fixed to the head of a straight vertical post 20. [ 0043 ] While, in the embodiment of Figure 5, the arrays of LEDs 3 are oriented in a direction opposite the second container body 6 and the LED lighting apparatus 1 is fixed to the head of a post 21 with a curved upper end portion. Alternatively, the LED lighting apparatus is fixed to a support arm, fastened on the wall of a building or on a straight vertical pole.

[ 0044 ] Similarly, in the embodiment of Figure 6, the arrays of LEDs 3 are instead oriented in a direction opposite the second container body 6 and the LED lighting apparatus 1 is suspended from a horizontal rope 22 by means of an attachment device 22.

[ 0045 ] From the above description it is clear that the lighting apparatus 1 allows fully achieving the intended purposes in terms of overcoming the drawbacks of the known art. In fact, the array of through apertures 10 allows dissipating the heat produced by the LEDs but, with respect to the known laminar structures, is much less vulnerable to the accumulation of dust and dirt. Moreover, since when it rains the rain water flows in the through apertures 10 crossing them, any undesired accumulations are removed.

[ 0046] Note that, by means of the LED lighting apparatus 1 according to this description, it is possible to provide a public lighting apparatus, such as, for example, a lamp post for public or street lighting comprising a lighting apparatus according to this description and a support post 20,21, a support bracket on a post or arm or an attachment device 18 to a rope 20 to which said LED lighting apparatus 1 is attached.

[0047] Without prejudice to the principle of the invention, the forms of implementation and construction details may be varied widely with respect to what has been described and illustrated purely by way of non- limiting example, without thereby departing from the invention as defined in the appended claims.