EP2547957B1

EP2547957B1 - Finned body for a power led lighting apparatus and lighting apparatus therewith

Info

Publication number: EP2547957B1
Application number: EP11729675.6A
Authority: EP
Inventors: Antonio Di Gangi
Original assignee: Individual
Current assignee: DI GANGI, ANTONIO
Priority date: 2010-03-17
Filing date: 2011-03-18
Publication date: 2018-10-03
Anticipated expiration: 2031-03-18
Also published as: EP2547957A2; ITPI20100029A1; WO2011114226A3; IT1398867B1; WO2011114226A2

Description

Field of the invention

The present invention concerns the field of lighting equipment, and more precisely it relates to a method for making a finned heat dissipation device for a lighting apparatus that comprises power LED chips.
Furthermore, the invention relates to a power LED lighting apparatus with a high performance cooling system.

Description of the prior art

As well known, very efficient lighting elements are available due to the development of LED technology. In fact, elements are available comprising power LED chips, which are made by microelectronic technology, where arrays consisting of a large number of single LED chips are very closely put together. The power of a LED chip may be several Watts, normally it may range from 1 Watt up to several tenths of Watts, and a very high efficiency can be attained, for example, a luminous efficacy of more than 100 lumen/watt.
Cooling is one of the most critical concerns of the equipment in which this kind of lighting element is used. In fact, the higher the temperature, the lower the efficiency of the electronics of the lighting elements, and if no temperature control is provided, they can bum out in a very short time.
Therefore, a power LED chip-based lighting element should not exceed a prefixed temperature limit, according to the manufacturer's suggestions. Accordingly, such elements must be assembled on a support that is adapted to absorb a large amount of heat, and to dissipate, when steady state conditions are established, all the adsorbed heat, thus remaining at a temperature lower than said temperature limit.
In the known LED lighting equipment, cooling is obtained by finned radiator elements, which, when exposed to outside air, allow a suitable dispersion of the heat generated by a power LED chip.
However, if many power LED chips are assembled on a same support to improve luminous efficacy, a problem arises of how to disperse all the heat.
For instance, a high power multi-LED projector can only be made, by the present techniques, if a forced air circulation is provided against the finned radiator elements.
However, the forced circulation, which is obtained by a fan, has the following drawbacks. Firstly, the use of a fan causes an additional energy consumption, which reduces one of the main advantages of power LED lighting apparatus, i.e. their low energy consumption. Moreover, the use of a fan affects the design of power LED lighting apparatus, thus hindering the designers' creativity. In addition, the mechanical parts of the fan often deteriorate over time, which reduces efficiency and produces irritating noise.
An example of a lighting apparatus that uses a fan for cooling the power LED light sources is disclosed in US20090323361 . In this case, fins are provided to improve the efficiency of the heat exchange between the air flow produced by the fan and the components to be cooled.
On the contrary, in EP2072893 a power LED lighting apparatus is described, in which no fan is provided. In this case, the cooling is carried out only by finned radiator elements which provide a plurality of heat exchange surfaces that extend radially from a cylindrical body.
Normally, a finned radiator element is manufactured by a molding process, in which high heat capacity materials are used. However, very large finned surfaces are required to dissipate heat naturally, i.e. without using fan elements.
Besides, more aesthetically pleasant casings may be used to hide the finned radiator elements. This way, however, the heat exchange efficiency decreases, which reduces the duration of the power LED chip.
In DE20315760 a lighting apparatus is described which comprises a finned radiator body that is connected to a head body containing a light source. The light source is arranged between the finned body and the head body and no direct contact is provided. In this case, the cooling of the light source is only partial and not so high to allow using a high power LED light source.
The document US 2006/198147 discloses an LED lighting device at which one side of the substrate where the LED's are mounted on provides cooling fins.

Summary of the invention

Accordingly, it is a feature of the present invention to provide a finned support body for a power LED chip that has a high heat dissipation efficiency and a reduced size.
It is also a feature of the present invention to provide a lighting apparatus that has such a finned support body for a power LED chip.
It is also a feature of the present invention to provide a lighting apparatus that allows an improved heat exchange, when such a finned body is used within a casing.
It is another feature of the present invention to provide a method for making a finned support body for a power LED chip that is easy and cost-effective to manufacture.
These and other objects are achieved by a finned body for a power LED lighting apparatus, comprising:

an conductive element made of a heat-conductive material, said conductive element having a front portion with a front seat for a power LED chip and a rear finned portion, wherein said rear finned portion comprises:
- starting at a measured distance D from said front seat, a first plane slit that ends at a root that has a circular cross section of determined diameter Φ, creating a support base of thickness D between said first slit and said front seat;
- starting at a measured distance D1 longer than D from said front seat, a second plane slit that ends at a root of said material that has a cross section of determined diameter Φ1, creating a first fin A1 between said first slit and said second slit;
- starting at a measured distance D2 longer than D1 from said front seat, a third plane slit that ends at a root of said material that has a cross section of determined diameter Φ2, creating a second fin A2 between said second slit and said third slit;
- further plane slits that form said rear finned portion with said first slit, said second slit and said third slit creating a respective fin Ai between two consecutive slits, each fin Ai of said rear finned portion located at a distance d_i from a previous fin, and each fin extending from a circular root of said material that has a cross section of diameter Φi,

Advantageously, second through holes are made on said front seat, in particular said second through holes are arranged more externally with respect to said first through holes, wherein said second through holes cross said finned body starting from said front seat towards said last fin, said second holes arranged to allow an axial air circulation and to assist heat exchange, in particular if the finned body is enclosed within a casing.
in particular, the distance d_i is a fixed distance, whereas the diameters Φi have decreasing values. This way, the root from which the fins extend has a conical shape, whose apex points towards a last fin An that is located at the farthest position from the front seat of the block where the power LED is mounted.
The conical shape of the root of the fins Ai optimizes cooling, since the heat flux and the temperature substantially decrease starting from the front seat where the power LED is mounted, towards the last fin. In this case, the maximum root cross section is located at the hottest region, i.e. at the centre of the support base. Such region serves as a heat accumulator, just next to the application seat for a power LED chip, where a maximum dissipation heat flux occurs.
Alternatively, the distance d_i and the diameters Φi are fixed lengths. In this case, the heat flux reaches more easily the fins that are located farthest from the application seat for a power LED chip.
Advantageously, all the fins Ai have a fixed radius.
Alternatively, a first group of fins of radius r1 and a second group of fins of radius r2 longer than r1 are provided, starting from said front seat towards said last fin. This way, the encumbrance of the front part of the finned body is reduced by making variable size fins, which assists the built-in installation and maximizes heat exchange surface. Preferably, said finned body comprises an externally screw threaded front fastening portion at said support base, said front fastening portion arranged to allow coupling of the finned body with a support sleeve that is adapted to support a reflector body and to allow built-in mounting, for example, within false ceilings, walls, and so on.
Advantageously, said screw threaded front fastening portion is treated with a heat conductive paste, for example with a silver heat conductive paste.
In particular, said finned body is anodized aluminum, preferably black anodized aluminum, in order to obtain a good heat conductivity also at the surface of it, thus increasing efficiency and duration of the power LED chip. For example a 6060, or 6026 or 6082, magnesium and silicon aluminum alloy may be used, which has a good machine tool workability.
According to another aspect of the invention, a power LED lighting apparatus is provided comprising a finned body, said finned body comprising:

an element made of a heat-conductive material, said element having a front portion with a front seat for a power LED chip and a rear finned portion, wherein said rear finned portion comprises:
- starting at a measured distance D from said front seat, a first plane slit that ends at a root that has a circular cross section of determined diameter Φ, creating between said first slit and said front seat a support base that has a thickness D;
- starting at a measured distance D1 longer than D from said front seat, a second plane slit that ends at a root of said material that has a cross section of determined diameter Φ1, creating a first fin A1 between said first slit and said second slit;
- starting at a measured distance D2 longer than D1 from said front seat, a third plane slit that ends at a root of said material that has a cross section of determined diameter Φ2, creating a second fin A2 between said second slit and said third slit;
- further plane slits that form said rear finned portion 10' with said first slit, said second slit and said third slit, creating a respective fin Ai between two consecutive slits, up to a last fin An, each fin Ai of said rear finned portion 10' located at a distance d_l from a previous fin, and each fin extending from a circular root of said material that has a cross section of diameter Φi,

Advantageously, a tubular casing is coupled with said finned body, said tubular casing having a bottom in which circulation apertures are made. This way, the apertures allow the passage of electrical supply wires and assist air circulation and change within the tubular casing of fresh air that skims over the finned body.
In particular, said tubular casing is fixed to said finned body by a ring nut provided with a plurality of axial holes that engage on said support base. This way, air circulation is allowed from a front space that surrounds said reflector body, towards a rear space, which surrounds said finned body.
In particular, an aperture ring mask is provided between said tubular casing and said reflector body, which allows air circulation between the environment about said tubular casing and said front space. In particular, a fresh air flow enters through the aperture mask into the front space that surrounds the reflector body, passes through the holes of said ring nut, passes through said rear space surrounding the finned body skimming over said fins, passes also through the holes of the finned body, thus mitigating its temperature, and flows outwards through the circulation apertures made through the bottom of the tubular body.
In particular, the ring nut and the tubular body are made of a heat-conductive material, such that a conduction heat flux occurs from said finned body towards said tubular body, the wide outer surface of which forms an ideal heat exchange surface for controlling the temperature of the finned body and, accordingly, the temperature of the power LED chip.
In a particular exemplary embodiment, a power LED lighting apparatus comprises a plurality of said finned bodies mounted on a plate that is made of a heat-conductive material, and in such a way that all finned bodies protrude from a first face of said plate, and that each front seat of said finned bodies protrudes from a second side of said plate opposite to said first face. A respective power LED chip and reflector bodies are mounted on each finned body, at said front seat. This way, an apparatus can be made which comprises a desired number of power LED chips. In particular, said plate serves as a support for an array of elementary lighting apparatus. Arranging said plate with a first side facing upwards, the array of elementary lighting apparatus is cooled naturally whichever is the lighting power of the apparatus to dissipate. For example, the plate may be suspended at a predetermined height with a second side facing downwards. The number of elementary lighting apparatus of the array may be selected responsive to the required luminance value.
In a floor lamp exemplary embodiment, the plate may have a first downwards-facing side, and a second upwards-facing side, in order to cast light downwards, and may have a plurality of holes made through the plate in order to cause warm air to circulate upwards through the plate.
According to a further aspect of the invention, a power led spotlight is characterized in that it comprises a finned body that is made according to the previous claims.
According to another aspect of the invention, the above described objects are achieved also by a method for making a finned body, such method comprising the steps of:

prearranging a conducting element made of a heat-conductive material;
making an application seat for a power LED chip on a front seat of said element;
causing said element to rotate;
starting at a measured distance D from said front seat, making a first plane slit on said element, up to leaving a root that has a circular cross section of determined diameter Φ, by means of a cutting tool that has a thickness less than 3 mm;
shifting said cutting tool to a distance d1 longer than D from said front seat and making a second plane slit up to leaving a circular root of said material that has a cross section of determined diameter Φ1;
shifting said cutting tool to a distance d2 longer than d1 from said front seat and making a second plane slit up to leaving a circular root of said material that has a cross section of determined diameter Φ2;
repeating the latter step up to obtaining a single finned body, wherein each fin is at a distance d_i from the previous fin, and each fin extends from a circular root of said material that has a cross section of diameter Φi, said finned body ending with a last fin An;
making on said front seat first through holes that cross said finned body starting from said front seat towards said last fin, said first holes arranged to receive electrical supply wires for said power LED chip.

Advantageously, a further step is provided of making second through holes on said front seat, in particular said second through holes arranged more externally with respect to said first through holes, wherein said second through holes cross said finned body starting from said front seat towards said last fin, said second holes arranged to allow an axial air circulation and to assist heat exchange, in particular if the finned body is enclosed within a casing.

Brief description of the drawings

The invention will be made clearer with the description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings, in which:

Fig. 1 shows a cross sectional view of a finned body, according to the invention;
Figs. 2 to 6 diagrammatically show a method for making the finned body of Fig. 1, for supporting a power LED chip, according to the invention;
Fig. 7 shows a perspective view of a lighting apparatus which comprises the finned body of Fig. 1;
Fig. 8 shows a diagrammatical elevational front view of the lighting apparatus in an application seat for the power LED chip;
Fig. 9 shows a diagrammatical view of the application seat for the power LED chip;
Fig. 10 shows a lighting apparatus having a tubular casing that contains the finned body, according to the invention;
Fig. 11 shows a cross sectional view of the lighting apparatus of Fig. 10 which depicts the air flow that crosses it and that is suitable for controlling the temperature of the finned body and, accordingly, the temperature of the power LED chip;
Figs. 12 and 13 show a perspective view of a composite lighting apparatus consisting of a plurality of elementary lighting apparatus;
Fig. 14 shows the composite lighting apparatus of Figs. 12 and 13 used as a floor lamp.

Detailed description of some exemplary embodiments

With reference to Fig. 1, a finned body 100 for a power LED lighting apparatus comprises a plurality of fins Ai at a distance d_i from one another. Each fin Ai extends from a root of material 3 that has a circular cross section of diameter Φi. In particular, root 3 extends from a support base 1 having a front face or portion 1a on which a front seat 2 is made for a power LED chip 20, shown hereinafter.
In the case of Fig. 6, distance d_i is a fixed distance, whereas diameters Φi have decreasing values. This way root 3, from which the fins Ai extend, has a conical shape, whose apex points towards a last fin An, opposite to front seat 2 of the block where power LED chip 20 is mounted.
The decreasing conical shape of root 3 of fins Ai optimizes cooling, since in the central part of support base 1 the heat generated by power LED chip 20 is collected and is quickly dissipated towards fins Ai through the large cross section of conical root 3. The conical shape allows the heat flux to reach all the fins starting from support base 1, on whose housing support 2 power LED chip 20 is mounted, towards last fin An.
In a way not shown, diameters Φi have a fixed value. In this case the root is cylindrical, and allows a high heat flux towards the farthest fins, which are close to last fin An, and are therefore adapted to dissipate a larger heat amount.
Each fin Ai may have a fixed radius or, as shown in Fig. 6, a proximal first unit of fins of radius r1 and a second distal unit of fins of radius r2 longer than r1 may be provided. Alternatively, in a way not shown, the diameter of the fins may increase starting from front seat 2 towards last fin An. This way, by making fins with different sizes, the encumbrance of the front part of the finned body is reduced by making variable size fins, in order to assist built-in installations and to maximize the heat exchange surface.
Support base 1 of finned body 100 comprises a screw threaded fastening portion 5, for connection with other parts of the lamp, which are shown hereinafter. Furthermore, the finned body has a first series of through holes 8a, for passage of supply wires, and can have a second plurality of aeration through holes 8b. Holes 8a, 8b, can be made as shown in Fig. 8, of which Fig. 1 is a cross sectional view, as indicated by arrows I-I. In Fig. 8, further holes 8c are shown for fixing power LED chip 20 by means of screws (for example Fig.8B, screws 63).
As diagrammatically shown in Figs. 2 to 6, a method is described for making finned body 100. In particular, the method comprises the steps of prearranging a raw block 10, for example as an end portion of a rod made of a heat-conductive material. In particular, the rod is made of anodized aluminum, in particular of black anodized aluminum, in order to obtain a good heat conductivity also at the surface, thus increasing the efficiency and the duration of the power LED chip. For example, a 6060, or 6026 or 6082 magnesium and silicon aluminum alloy may be used, which has a good machine tool workability.
At first, housing support 2 is made on front face 1a of block 10 for a power LED chip 20. The operation comprises using cutting instruments 40, for leveling and working front seat 2, as well as a step of cylindrical grinding external surfaces 5, 6 and 7. Front seat 2 may comprise a protruding reference edge 4. In particular, the various working steps are carried out by means of a numerical control lathe.
Then, as shown in the section of Fig. 3, longitudinal through holes 8a and 8b are made on element 10 by a boring tool 41, starting from front seat 2. For example, a step of boring may be carried out by means of a multiple boring tool.
Subsequently, fins A1, A2, A3,... are made on element 10 mounted on a lathe (Fig. 4) by means of a cutting tool 42, which has a cut width lower than 3 mm, for example 2 mm, starting at a measured distance D from front seat 2, in order to form support base 1 of thickness D. The first plane slit F1 is made by cutting tool 42 up to leaving a root that has a circular cross section of determined diameter Φ.
Tool 42 is then moved forward (Fig. 5) from front seat 2 for a distance d1 longer than D, to make a second plane slit F2 up to leaving a root of material that has a circular cross section of determined diameter Φ1 (Fig.4). This way, first fin A1 is created between two slits F1 and F2.
In the same way (Fig. 6), by moving cutting tool 42 from front seat 2 for a distance d2 longer than d1, a third plane slit F3 is made up to leaving a circular root of the material that has a cross section of determined diameter Φ2, and second fin A2.
Repeating these operations, finned body 100 is obtained, as shown in Fig. 1, in which each fin is at a distance di from the previous fin, and each fin Ai extends from a root of material that has a circular cross section of diameter Φi. This way, the root from which the fins extend has a conical shape, whose apex points towards last fin An.
As above described, screw threaded front fastening portion 5 (Fig. 1) is used for coupling parts of a lighting apparatus in which finned body 100 is used as a temperature regulation element of a power LED chip 20.
For example, in Fig. 7 a spotlight is shown for built-in installation, which is obtained by fixing to finned body 100 a sleeve 140 provided with an abutment flange 130. Sleeve 140 can be mounted by adding a heat conductive paste on screw threaded front fastening portion 5 of Fig. 1, for example a silver heat conductive paste or any suitable product that is available on the market. This way, also sleeve 140, which is made of a heat conductive material, assists cooling finned body 100.
Fig. 7 shows how a reflector 110 is arranged within flanged sleeve 140. The reflector is closed by a protection glass or lens, not shown. Power LED chip 20 is arranged at the centre of the reflector, for example it is mounted on an aluminum plate 21. The electric connection is provided by electric cables 61, which attains power LED chip 20 through holes 8a.
Power LED chip 20 may be equipped with an external power supply device, or it may be in the form of an integrated circuit, for example a multicore LED with printed integrated circuit board.
A remote power supply is also possible, by a wireless communication with the LED light source. Plate 21 and chip 20 are shown more in detail in Fig. 9, where welding points 62 of cables 61 are shown, which protrude from holes 8a, at angular slits 64 of plate 21. Furthermore, montage screws 63 are shown through blind holes 8c (Fig. 8) at housing 2 of finned body 100.
With reference to Figs. 10 and 11, another power LED lighting apparatus has a finned body 100 (Fig.11) to which a cylindrical sleeve 140' may be connected instead of a flanged sleeve. On the extension of the cylindrical sleeve 140', a tubular casing 120 may be connected which has a bottom 121 where circulation apertures are made, for example by means of a grid 180. This way, the apertures allow the passage of electrical supply wires and assist air circulation and change within the tubular casing 120.
In particular, tubular casing 120, or sleeve 140', or a one-piece tubular body, not shown, is connected to the finned body by a ring nut 145 provided with a plurality of axial holes 146 that engage with support base 1. This way, air circulation is allowed from a front space 150, which surrounds reflector body 110, towards a rear space 170, which surrounds finned body 100.
In particular, between tubular sleeve 140' and reflector body 110, an aperture ring mask 130 is provided which is coupled with tubular sleeve 140' by a ring lock 132 and which allows air circulation 160 between the environment about the tubular casing and front space 150, through holes 131. In particular, a fresh air flow enters front space 150 that surrounds reflector body 110 through aperture mask 130, passes through holes 146 of ring nut 145, passes through rear space 170 that surrounds finned body 100 skinning fins Ai, and also flows along through holes 8b of the finned body, controlling its temperature, and flows outwards through the circulation apertures that are obtained on a end grid 180 of tubular body 120.
In particular, ring nut 145 and tubular body 120,140' are made of a heat-conductive material, such that a conduction heat flux occurs from said finned body 100 towards said tubular body 120,140', the wide outer surface of which forms an ideal heat exchange surface for controlling the temperature of finned body 100 and, accordingly, the temperature of power LED chip 20.
In Fig. 11, a protection glass 191 is also shown, which can also be a lens, as well as a projection space 190 of the light generated by LED chip 20. Furthermore, in Fig. 10 a fastening 122 is shown that is intended for a support, not shown, of the lighting apparatus.
In a further exemplary embodiment, as shown in Figs. 12,13 and 14, a power LED lighting apparatus 200 is characterized in that it comprises a plurality of finned bodies 100 (Fig. 13) made as described above, and mounted on a plate 201 of a heat-conductive material, in such a way that all finned bodies protrude from a first face 202 of the plate, and that each front seat 2 of the finned bodies protrudes from a second side 203 of plate 201 (Fig. 12) opposite to first face 201. A power LED chip 20 and a reflector body 110 are mounted on each finned body 100, at front seat 2.
Finned body 100 can be coupled with plate 201 by screwing it at screw threaded front fastening portion 5 of Fig. 1, by adding conductive varnish or paste, for example a silver heat conductive paste or any suitable product that is available on the market. This way, also plate 200, made of a heat conductive material, helps cooling finned body 100 with its large surface. Even the external frame of apparatus 200 assists heat exchange.
In such a multiple configuration, an apparatus can be made which can have any number of power LED chips. In particular, the plate serves as a support for an array of elementary lighting apparatus (in the pictures an array of more elements is shown just as an example). By arrangement plate 200 with first upwards-facing side 202, the array of elementary lighting apparatus is cooled naturally whichever the lighting power of the apparatus may be. For example, the plate can be suspended at a predetermined height as shown in Fig. 12 with second side 203 facing downwards. The number of elementary lighting apparatus of the array may be established according to the required luminance value. This way, an apparatus of even hundreds of elements can be made, for example for lighting such large places as fitness facilities, theaters, factory sheds.
In a floor lamp exemplary embodiment, plate 201 may have first downwards-facing side 202, and second upwards-facing side 203, in order to cast light downwards, and may have a plurality of holes 204 made through the plate in order to cause warm air to circulate through plate 201 itself.
First face 202 may be protected in a not shown way by a grid that allows an easy air passage.
The foregoing description of a specific exemplary embodiment, will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such specific embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to perform the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.

Claims

A finned body (100) comprising a power LED chip for a lighting apparatus (20) comprising:
- an element (10) made of a heat-conductive material, said element (10) having a front portion (1a) with a front seat (2) for a power LED chip (20) and a rear finned portion (10'), wherein said rear finned portion (10') comprises:
- starting at a measured distance D from said front seat (2), a first plane slit (F1) that ends at a root (3) that has a circular cross section of determined diameter Φ, creating between said first slit (F1) and said front seat (2) a support base (1) that has a thickness D;

- starting at a measured distance D1 longer than D from said front seat (2), a second plane slit (F2) that ends at a root (3) of said material that has a cross section of determined diameter Φ1, creating a first fin A1 between said first slit (F1) and said second slit (F2);

- starting at a measured distance D2 longer than D1 from said front seat (2), a third plane slit (F3) that ends at a root (3) of said material that has a cross section of determined diameter Φ2, creating a second fin A2 between said second (F2) and said third slit (F3);

- further plane slits Fi that form said rear finned portion (10') with said first slit (F1), said second slit (F2) and said third slit (F3), creating a respective fin Ai between two consecutive slits, up to a last fin An, each fin Ai of said rear finned portion (10') at a distance d_i from a previous fin, and each fin extending from a circular root of said material that has a cross section of diameter Φi,
wherein first through holes (8a) are made on said front seat (2), said through holes crossing said finned body (100) starting from said front seat (2) towards said last fin An, said first holes (8a) arranged to receive electrical supply wires for said power LED chip (20);
said finned body (100) characterized in that second through holes (8b) are made on said front seat (2), in that said second through holes (8b) cross said finned body (100) starting from said front seat (2) towards said last fin and in that said second through holes (8b) are arranged to allow an axial air circulation and to assist heat exchange.
A finned body (100) according to claim 1, wherein said second through holes are arranged more externally with respect to said first through holes (8a) .
A finned body (100) according to claim 1, wherein the distances d_i is a fixed distance, whereas diameters Φi have decreasing values, in particular a first group of fins of radius r1 and a second group of fins of radius r2 longer than r1 being provided, starting from said front seat (2) towards said last fin An.
A finned body (100) according to claim 1, wherein said finned body (100) comprises a front fastening portion (5) that is externally screw threaded at said support base (1), said front fastening portion arranged to couple the finned body (100) with a support sleeve (140), said support sleeve (140) arranged to support a reflector body (110) and to allow its mounting, for example, in false ceilings, walls, etc., in particular, said screw threaded front fastening portion (5) is treated with a heat conductive paste, for example with a silver heat conductive paste.
A finned body (100) according to claim 1, wherein said finned body (100) is made of anodized aluminum, in particular of black anodized aluminum, in order to obtain a good heat conductivity also at the surface, thus increasing the efficiency and the duration of the power LED chip (20).
A power LED lighting apparatus (20) comprising a finned body (100), said finned body (100) comprising:
- an element (10) made of a heat-conductive material, said element (10) having a front portion (1a) with a front seat (2) for a power LED chip (20) and a rear finned portion (10'), wherein said rear finned portion (10') comprises:
- starting at a measured distance D from said front seat (2), a first plane slit (F1) that ends at a root (3) that has a circular cross section of determined diameter Φ, creating between said first slit and said front seat (2) a support base (1) that has a thickness D;

- starting at a measured distance D1 longer than D from said front seat (2), a second plane slit (F2) that ends at a root (3) of said material that has a cross section of determined diameter Φ1, creating a first fin A1 between said first slit and said second slit;

- starting at a measured distance D2 longer than D1 from said front seat (2), a third plane slit (F3) that ends at a root (3) of said material that has a cross section of determined diameter Φ2, creating a second fin A2 between said second slit and said third slit;

- further plane slits that form said rear finned portion with said first slit, said second slit and said third slit, creating a respective fin Ai between two consecutive slits, up to a last fin An, each fin Ai of said rear finned portion (10') located at a distance d_i from a previous fin, and each fin extending from a circular root of said material that has a cross section of diameter Φi,
wherein said power LED chip (20) and a reflector body (110) are mounted on said finned body (100), at said front seat (2);
said power LED lighting apparatus (20) characterized in that second through holes (8b) are made on said front seat (2), in that said second through holes (8b) cross said finned body (100) starting from said front seat (2) towards said last fin, and in that said second holes (8b) are arranged to allow an axial air circulation and to assist heat exchange.
A lighting apparatus according to claim 6, wherein a tubular casing (120) is coupled with said finned body (100), said tubular casing having a end (121) in which circulation apertures (180) are made, in particular said tubular casing (120) is fixed to said finned body (100) by a ring nut (145) that has a plurality of axial holes (146) and that engages on said support base (1) in particular an aperture ring mask (130) being provided between said tubular casing (120) and said reflector body (110), said aperture ring mask allowing air circulation between the environment about said tubular casing (120) and a front space (150).
A lighting apparatus according to claim 6, wherein distance d_i is a fixed distance, whereas diameters Φi have decreasing values.
A lighting apparatus according to claim 6, wherein a first group of fins of radius r1 and a second group of fins of radius r2 longer than r1 are provided, starting from said front seat (2) towards said last fin An.
A lighting apparatus according to claim 6, wherein said finned body (100) comprises a front fastening portion (5) that is externally screw threaded at said support base (1), said front fastening portion arranged to couple the finned body (100) with a support sleeve (140), said support sleeve (140) arranged to support a reflector body (110) and to allow its mounting, for example, in false ceilings, walls, etc., in particular, said screw threaded front fastening portion (5) is treated with a heat conductive paste, for example with a silver heat conductive paste.
A lighting apparatus according to claim 6, wherein first through holes (8a) are made on said front seat (2), said through holes crossing said finned body (100) starting from said front seat (2) towards said last fin, said first holes (8a) arranged to receive electrical supply wires for said power LED chip (20).
A lighting apparatus according to claim 6, wherein said second through holes are arranged more externally with respect to said first through holes (8a) .
A power LED lighting apparatus (20) characterized in that it comprises a plurality of finned bodies (100) that are made according to the previous claims, and are mounted on a plate (201) made of a heat-conductive in such a way that all finned bodies protrude from a first face (202) of said plate (201), and that each front seat (2) of said finned bodies (100) protrudes from a second side (203) of said plate (201) opposite to said first face (202), wherein a respective power LED chip (20) and a reflector body (110) are mounted on each finned body (100), at said front seat (2).
A power led spotlight characterized in that it comprises a finned body (100) that is made according to the previous claims.
A method for making a finned body (100) comprising the steps of:
- prearranging an element (10) made of a heat-conductive material;

- making an application seat for a power LED chip (20) on a front seat (2) of said element (10);

- causing said element (10) to rotate;

- starting at a measured distance D from said front seat (2), making a first plane slit (F1) on said element (10), up to leaving a root (3) that has a circular cross section of determined diameter Φ, by means of a cutting tool that has a thickness less than 3 mm;

- shifting said cutting tool to a distance D1 longer than D from said front seat and making a second plane slit (F2) up to leaving a circular root of said material that has a cross section of determined diameter Φ1;

- shifting said cutting tool to a distance D2 longer than D1 from said front seat and making a second plane slit (F2) up to leaving a circular root of said material that has a cross section of determined diameter Φ2;

- repeating the above step up to obtaining a single finned body (100), wherein each fin is at a distance di from the previous fin, and each fin extends from a circular root of said material that has a cross section of diameter Φi, said finned body (100) ending with a last fin An,

- making first through holes (8a) on said front seat (2), said first through holes (8a) crossing said finned body (100) starting from said front seat (2) towards said last fin, said first holes (8a) arranged to receive electrical supply wires for said power LED chip (20);
a further step being provided of making second through holes (8b) on said front seat (2), said second through holes crossing said finned body (100) starting from said front seat (2) towards said last fin, and arranged to allow an axial air circulation and to assist heat exchange.