[0001] The present invention refers to a lighting device for use outdoors and in large covered
areas, in the public and private sectors, distinguished by an optimized heat dissipation.
The lighting device for outdoors and large covered areas according to the present
invention is based on the use of preferably high power LEDs as the light source.
[0002] High power LEDs have seen continuous and progressive improvements, over the last
years, in terms of light efficiency and they are considered the light source of the
next generation for general lighting applications. Moreover, the absence of light
pollution and the drastic reduction of maintenance costs, ensured by this type of
light source, opens the doors to a rapid penetration on the market, with a gradual
replacement of conventional lighting sources for outdoors and large covered areas,
like high pressure sodium and metal iodides.
[0003] One of the main advantages of the high power LED light source comes from the fact
that, if correctly managed, it can have a useful life which is greater than 50.000
hours, with consequent advantages for the maintenance of the lighting device.
[0004] However, such an LED light source, in particular if it is high power, although it
offers high light efficiency, has an intrinsic amount of power which is not converted
into light but consists of heat to be disposed of.
[0005] Therefore, in the absence of suitable dissipation elements that are suitably sized
so as to have a sufficient heat exchange surface, there is a rapid deterioration of
the LED devices themselves, in particular if the junction temperature of such devices
exceeds a predetermined limit value.
[0006] The performance of the dissipation elements is thus fundamental in order to reach
the useful life objectives in the final product. Its purpose is to keep the temperature
of the lighting device at values which are not dangerous for the life of the LED light
sources.
[0007] An optimal sizing of the dissipating elements makes it possible to increase the service
life of the product and thus to reduce the costs and maintenance time it requires.
[0008] On the contrary, an inadequate dissipator causes the performance to decrease rapidly
or causes the lighting device to break.
[0009] The lighting devices for outdoors and large covered areas known to this day, having
one or more LEDs as their light source, are thus designed in a way such as to foresee
at least one suitably sized dissipator element in contact with the LED light sources.
[0010] However, the solutions adopted nowadays, for making the dissipator elements do not
make it possible to achieve satisfactory performance in terms of dissipation, in particular
in the case in which there are many sources, in relation to the homogeneity and the
efficiency of the cooling effect.
[0011] This is often due to the fact that in the dissipators used in the known LED lighting
devices for outdoors and large covered areas, the cooling air is not typically able
to reach the centre of the dissipator.
[0012] The purpose of the present invention is that of avoiding the aforementioned drawbacks
and in particular that of conceiving an LED lighting device for outdoors and large
covered areas that, for the same dissipating surface of the dissipating element used,
offers improved dissipation performance.
[0013] A further purpose of the present invention is that of making an LED lighting device
for outdoors and large covered areas, which is able to produce a homogeneous and efficient
cooling effect on the LEDs.
[0014] Last but not least purpose of the present invention is that of conceiving an LED
lighting device for outdoors and large covered areas, which offers a particularly
long service life.
[0015] These and other purposes according to the present invention are achieved by making
an LED lighting device for outdoors and large covered areas as outlined in claim 1.
[0016] Further characteristics of the LED lighting device for outdoors and large covered
areas are object of the dependent claims.
[0017] The characteristics and the advantages of an LED lighting device for outdoors and
large covered areas according to the present invention shall become clearer from the
following description, given as an example and not for limiting purposes, with reference
to the attached schematic drawings in which:
- figure 1 is a perspective view from below of a first embodiment of the LED lighting
device for outdoors and large covered areas according to the present invention;
- figure 2 is a perspective view from above of the LED lighting device for outdoors
and large covered areas of figure 1;
- figure 3 is a section view of the LED lighting device for outdoors and large covered
areas of figure 1, in which the arrows represent the direction in which the air passes
through the device;
- figure 4 is an enlarged detail of figure 3;
- figure 5 is a perspective view from above of a second embodiment of the LED lighting
device for outdoors and large covered areas according to the present invention;
- figure 6 is an enlarged detail in section of the LED lighting device for outdoors
and large covered areas of figure 5, in which the arrows represent the direction in
which the air passes through the device;
- figure 7 is a perspective view from above of a third embodiment of the LED lighting
device for outdoors and large covered areas according to the present invention;
- figure 8 is an enlarged detail in section of the LED lighting device for outdoors
and large covered areas of figure 7, in which the arrows represent the direction in
which the air passes through the device;
- figure 9 is a perspective view from above of a fourth embodiment of the LED lighting
device for outdoors and large covered areas according to the present invention;
- figure 10 is an enlarged detail in section of the LED lighting device for outdoors
and large covered areas of figure 9, in which the arrows represent the direction in
which the air passes through the device.
[0018] With reference to the figures, an LED lighting device for outdoors and large covered
areas is shown, wholly indicated with reference numeral 10.
[0019] According to the present invention, the LED lighting device for outdoors and large
covered areas 10 comprises a plurality of, preferably high power, LED light sources
11 directly constrained to a finned body which constitutes the lamp body 13.
[0020] The finned ring lamp body 13, to which the plurality of LED light sources 11 is constrained
underneath, has a substantially flat ring base 13a from the top of which a plurality
of fins 13b, substantially arranged along the entire ring defined by the lamp body
13, projects upwards.
[0021] By ring shape it is not only referred to a perfectly circular flat plan shape, but
generic shapes are meant which are centrally hollow, for example having a an elliptical,
square or rectangular base and so forth, the said shapes following the profile of
surfaces which are not necessarily flat, such as for example curved surfaces, or surfaces
having a profile corresponding to a broken line.
[0022] The ring base 13a acts as a surface for coupling with at least one lower optical
element 12, on which there is a plurality of lenses 18 arranged in matrixes.
[0023] The optical element 12 below is in general constrained to the lamp body 13 through
suitable constraining means 20.
[0024] The group made of the lamp body 13 and the optical element 12 forms a toroid 12,13.
[0025] The lamp body 13 and the optical element 12 define inside the toroid 12,13 a substantially
flat first chamber 11a, in which the LED light sources 11 are housed.
[0026] The LED light sources 11 with the relative circuitry 11b, are also constrained to
the finned ring lamp body 13 through the action of the constraining means 20 which
keep the optical element 12 constrained to the lamp body 13.
[0027] Particularly, the plurality of LED light sources 11 and the relative circuitry 11b
are directly constrained to the bottom of the ring base 13a of the lamp body 13, whereas
from the top of the ring base 13a the plurality of fins 13b projects upwards.
[0028] Further, next to both sides of the optical element 12 there is a mask element 14
that, along with the lamp body 13, defines a second chamber 14b for housing the cables
for supplying power to the LED light sources 11. The mask element 14 is also constrained
to the lamp body 13 through suitable constraining means (not illustrated).
[0029] The mask element 14, joining up with the lenses 18 so as to form a lower transparent
surface of a material similar to that of the lenses 18 themselves, offers a homogeneous
visual effect.
[0030] The positioning and the distribution of the light sources 11 follow the profile outlined
by the finned ring lamp body 13.
[0031] Preferably, the LED light sources 11 are arranged in groups of matrixes in which
each matrix is associated with an optical element 12, in such a manner that the single
LED light source 11 is optically coupled with a single lens 18, forming part of the
optical element 12. The resulting light distribution on the ground is thus made up
of the sum of all the single flows coming out from every optical element 12, which
therefore equally contribute to lighting up the street area to be lit.
[0032] Moreover, the mask element 14 makes it possible to have a homogeneous visual appearance
of the lighting apparatus for outdoors and large covered areas, due to the fact that
it gathers the light emitted laterally by the optical elements 12 and diffuses it
through a plurality of prisms 14a formed on the mask element 14. The effect obtained
is that, when turned on, the lighting device seems like a uniform ring of light thus
masking the plurality of single spot lights.
[0033] The fins 13b of the finned ring body 13 can take on any profile, even different from
one another, according to the overall shape which is wished to be given to the lighting
device for outdoors and large covered areas 10, as well as according to the type (conduction
and/or convection) and quantity of heat transmission that is wished to be obtained
through the finned ring body 13. In order to ensure an optimal conduction, the plurality
of fins 13b is uniformly distributed along the entire extension of the ring base 13a.
Moreover, the single fins 13b are made with a thickness which is as thin as possible,
where the limit of the choice of thickness depends on the type of material used as
well as on the technology used for making the finned body 13.
[0034] In the embodiments illustrated, in which the lamp body 13 has a circular shape, the
fins 13b are arranged along radiuses whose geometrical centre coincides with the centre
of the lamp body 13.
[0035] This geometry promotes uniformity of the thermal path. Moreover, such an arrangement
does not have a single preferential direction, and thus expresses a better behaviour,
in operating conditions, when there is wind. The spacing between the fins 13b is defined
according to a volumetric approach to the natural convection. Indeed, if two fins
13b are too close together they affect each other negatively whereas, if they are
too far apart the overall number of fins 13b of the finned ring lamp body 13 and thus
the total surface of heat exchange is reduced.
[0036] The optimal spacing is that which maximises the coefficients of heat exchange and
thus the total power transmitted to the environment, according to the sizes of the
dissipator, in turn depending on the overall sizes of the lighting device 10 and depending
on the limit temperature one wishes to have at the lamp body 13 itself.
[0037] Therefore, in the embodiment illustrated, fins 13b extending for the entire thickness
of the lower ring base 13a, are alternated with fins 13b' which extend for only a
portion of such a thickness, in particular arranged in the outermost portion of the
finned ring lamp body 13. This is done so as to exploit the fact that, at the outermost
portion, the circular-shaped finned ring lamp body 13 has a circumference which is
greater and thus has more space for housing such fins 13b without having them excessively
close to one another.
[0038] The finned ring lamp body 13, being configured according to a closed profile, creates
a central cavity that, for the same overall size of the lighting device, makes it
possible to have a cool air flow towards the fins 13b, coming both from the outer
perimeter of the device, and from the inner perimeter corresponding to the perimeter
of the cavity, as illustrated in figures 3, 4, 6 and 8.
[0039] In such a way, the fins 13b have a marked phenomenon of thermal convection which
takes the heat away from the lamp body 13.
[0040] The heat dissipation is thus improved with respect to the condition of dissipators
known nowadays, in which the cooling air is typically not able to reach the centre
of the dissipator causing the cooling effect to be heterogeneous and inefficient.
[0041] In the LED lighting device for outdoors and large covered areas 10 according to the
present invention provided with a central cavity, there are two directions in which
the air can flow through the fins 13b cooling them on both sides, inside and outside,
with consequent increase of the heat dissipation performance.
[0042] The fins 13b, 13b' of the finned lamp body 13 are preferably interrupted in one or
more sectors of such a body 13 in which hollow compartments 13c, 15 are arranged.
[0043] As shown in figure 2, it is possible to foresee a single hollow compartment 15 suitable
for housing electronic means (not illustrated) inside of it, necessary for supplying
power and, preferably, also for managing the lighting device 10, such as a power supply
unit and a plurality of sensors and/or actuators. Alternatively, as illustrated in
figure 5, it is possible to conceive making, in predetermined positions, an additional
plurality of hollow compartments 13c suitable for the same purpose.
[0044] The power supply unit dispenses the correct power supply to both the LED light sources
11 of the lighting device 10, and the further electronic means.
[0045] Such electronic means are used to manage the communication between the lighting device
for outdoors and large covered areas 10 and a remote control unit, which verifies
the correct operation of the device 10 and records the sent data (signals, anomalies,
images and so forth).
[0046] The communication is managed through a control unit integrated in the power supply
unit of the lighting device for outdoors and large covered areas 10 suitable for recording
possible anomalies and for transmitting the operation parameters to a connection unit
installed in the electrical distribution cabin, which in turn is connected to a remote
control station.
[0047] In addition, the electronic means housed in the hollow compartment 15 can comprise
a
webcam, for recording and sending images to a remote unit, and/or a pollution sensor for
recording the air quality, and/or temperature sensors and/or smoke sensors for fire
safety and/or anti-intrusion movement sensors for private use.
[0048] Moreover, at a higher level of integration, the electronic means can be active devices,
amongst which, for example, an extinguisher system which operates in the case of fire,
detected by the temperature and/or smoke sensors.
[0049] For hooking the LED lighting device for outdoors and large covered areas 10 onto
a respective support pole, suitable hooking means 16 are foreseen comprising a first
portion 16a integral with the finned ring lamp body 13 connected by means of a pivot
to a second hollow tube-shaped portion 16b, suitable for cooperating with the support
pole of the lighting device for outdoors and large covered areas 10.
[0050] In the case in which the first portion 16a of the hooking means 16 is integral with
a hollow compartment 15, 13c of the lamp body 13, it preferably has a finning 16c
intended for the thermal dissipation of the electronic means contained in the compartment
15, 13c itself, as illustrated in figures 5, 7 and 9.
[0051] In the embodiments illustrated in figures 7-10, a screen 19 is also advantageously
foreseen, above the finned ring lamp body 13, having the same ring shape and a suitably
shaped profile which further improves the dissipation performance of the finned ring
lamp body 13.
[0052] The upper screen 19 constitutes a protection from direct solar radiation, for all
the electronic components of the lighting device 10.
[0053] Indeed such a radiation has a negative effect on the electronic components even when
they are turned off, since it could cause limit temperature thresholds to be exceeded,
causing the life of the components themselves to be shortened.
[0054] The advantage of using a solar screen 19 is even more obvious at sunset, which is
the moment when the lighting device is turned on and, depending on the geographical
location in which it is installed and on the season, it could be operating in critical
environmental conditions, if it did not have the screen.
[0055] The protection offered by the screen 19 against solar radiation indeed keeps the
lighting device, and thus the LED light sources 11 and the finned lamp body 13, at
a lower temperature with respect to what it would be without the screen 19, positively
contributing to the thermal dissipation and to the useful life of the device 10.
[0056] The screen 19 can advantageously be connected to a hollow body 15, 13c through suitable
connection means 21.
[0057] Specifically, the screen 19 has a profile which at least partially follows the profile
of the fins 13b, 13c and on top of it, it can have some slits 22 for disposing of
the heat released by the fins 13b, 13c. The arrangement of the slits 22 shown in figures
7 and 8 is not restricted to the number, size and shape of the slits 22 themselves.
[0058] If there are no slits 22, the screen 19 is configured in such a manner that the fins
13b, 13c themselves create a channel 17 with parallel walls having a substantially
ascending direction or, at least, having an inlet 17a and an outlet 17b, in which
the inlet of the channel 17a is positioned in a lower position with respect to the
outlet 17b.
[0059] The screen 19 thus makes it possible to obtain an increased air flow through the
fins 13b of the finned body 13, as illustrated in figure 10.
[0060] Indeed, at the inlet 17a of the channel 17 formed by the finned lamp body 13 and
by the screen 19 there is cool air at atmospheric pressure. Inside the channel 17,
on the other hand, there is a low pressure area and a high temperature.
[0061] A pressure difference is thus created between the inner and outer area of the channel
17, which accentuates even more the cool air flow entering in the finned body 13 in
at least one of the two flow directions outlined in relation to the embodiments without
a screen 19.
[0062] This flow can be amplified by the presence of wind which impacts the surface of the
screen 19.
[0063] From the description made, the characteristics of the electronic system object of
the present invention as well as the relative advantages should be clear.
[0064] The LED lighting device for outdoors and large covered areas according to the present
invention is indeed able to offer an increased dissipation effect for the same dissipation
surface of the dissipation element used, obtaining a homogeneous and efficient cooling
effect on the LEDs. In such a way, a long service life of the lighting device for
outdoors and large covered areas according to the present invention is ensured.
[0065] It should finally be clear, that the LED lighting device for outdoors and large covered
areas thus conceived can undergo numerous modifications and variants, all covered
by the invention; moreover, all the details may be replaced by technically equivalent
elements. In practice the materials used, as well as the sizes, can be any according
to the technical requirements.
1. LED lighting device (10) for outdoors and large covered areas comprising a plurality
of LED light sources (11) constrained to a lamp body (13) characterised in that said lamp body (13) has a finned ring shape, at least one substantially flat optical
element (12) being constrained at the bottom to said finned ring lamp body (13), said
finned ring lamp body (13) and said at least one optical element (12) defining a first
chamber (11a) for housing said plurality of LED light sources (11) and circuitry (11b)
for managing said plurality of LED light sources (11).
2. LED lighting device (10) for outdoors and large covered areas according to claim 1
characterised in that said at least one optical element (12) comprises a plurality of lenses (18) arranged
in matrixes.
3. LED lighting device (10) for outdoors and large covered areas according to claim 2
characterised in that said plurality of LED light sources (11) is arranged in groups of matrixes distributed
along the development of said finned ring lamp body (13), each of said LED light source
matrixes (11) being associated with a lens matrix (18) such that each light source
(11) of said plurality of LED light sources (11) is optically coupled with a lens
(18) of said plurality of lenses (18).
4. LED lighting device (10) for outdoors and large covered areas according to any one
of the previous claims characterised in that said finned ring lamp body (13) comprises a ring base (13a) from which a plurality
of fins (13b) extends.
5. LED lighting device (10) for outdoors and large covered areas according to claim 4
characterised in that said fins (13b) are uniformly distributed along the development of said ring base
(13a).
6. LED lighting device (10) for outdoors and large covered areas according to one of
claims from 4 to 5 characterised in that said finned ring body (13) has a circular shape, said fins (13b) being arranged along
radiuses whose geometrical centre coincides with the centre of said finned ring body
(13).
7. LED lighting device (10) for outdoors and large covered areas according to claim 6
characterised in that first fins (13b) alternate along the development of said ring base (13a), which fins
extend for the entire thickness of the ring base (13a) below, and second fins (13b')
which extend only for part of such thickness, said second fins (13b') being arranged
in an outermost portion of said finned ring body (13).
8. LED lighting device (10) for outdoors and large covered areas according to any one
of claims from 4 to 7 characterised in that said succession of fins (13b,13b') is interrupted at least at one sector (15,13c)
of said finned ring body (13), a hollow compartment (15,13c) being arranged in said
at least one sector (15, 13c) .
9. LED lighting device (10) for outdoors and large covered areas according to claim 8
characterised in that electronic means are arranged within said at least one hollow compartment (15,13c).
10. LED lighting device (10) for outdoors and large covered areas according to any one
of the previous claims characterised in that support pole hooking means (16) are connected to said finned ring lamp body (13),
said hooking means (16) comprising a first portion (16a) integral with said lamp body
(13) connected by means of one pivot to a second hollow tube-shaped portion (16b).
11. LED lighting device (10) for outdoors and large covered areas according to claim 10
characterised in that said first portion (16a) of said hooking means (16) integral with said lamp body
(13) is finned.
12. LED lighting device (10) for outdoors and large covered areas according to any one
of the previous claims characterised in that a mask element (14) is further constrained at the bottom to said finned lamp body
(13), said mask element (14) defining with said finned lamp body (13) a second chamber
(14b) for the passage of power cables of said plurality of LED light sources (11).
13. LED lighting device (10) for outdoors and large covered areas according to claim 12
characterised in that said mask element (14) comprises a plurality of prisms (14a) for the diffusion of
light emitted laterally by said at least one optical element (12).
14. LED lighting device (10) for outdoors and large covered areas according to any one
of claims from 4 to 13 characterised in that it comprises, on top of said finned ring lamp body (13), a screen (19) having the
same ring plan, and having a section profile corresponding to at least part of the
profile of said fins (13b), said screen (19) forming with said finned ring lamp body
(13) a channel (17) having an inlet (17a) and an outlet (17b) for an air flow, said
inlet (17a) being placed in a lower position with respect to said outlet (17b).
15. LED lighting device (10) for outdoors and large covered areas according to claim 14
characterised in that said screen (19) has a plurality of slits (22).