[0001] The present invention refers to an LED lighting electric device comprising:
- an LED light source mounted and powered on a support card;
- a corresponding waveguide associated with the light source to diffuse the light beam
generated by said source;
- a lens supported in a predetermined spaced apart relationship with said light source;
- transparent support legs formed in one piece with the waveguide or with said lens
and extending around said light source.
The invention also concerns a lighting apparatus, for instance a lamp or a headlight,
including a plurality of said LED lighting electric devices.
The invention also concerns a method for producing said LED lighting electric devices.
Field of application
[0002] As is well known in this specific technical field, over the past few years a new
artificial lighting technology has become popular, based upon semiconducting light
emitting diodes, so-called LEDs. LEDs are powered by means of a suitable electronic
circuit and their light is generated by a physical process called "Electron-hole recombination"
that results in the emission of light particles, in other words photons.
[0003] The average life of an LED is estimated to be tens of times greater than most light
bulbs or discharge lamps that, in optimal conditions of continuous use, can respectively
reach a maximum of 2000 or 7000 hours of operation. LEDs, on the other hand, can ideally
last 50,000 hours or more.
[0004] Moreover, LEDs consume much less electrical energy and can play a fundamental role
in the reduction of the costs linked to electrical energy consumption.
[0005] Currently, LEDs are still relatively expensive, set to fall in the future as they
are used more extensively, but LED lighting can already offer savings in the medium
and long term thanks to their lower consumption, their greater lifetime and their
very low maintenance.
Prior art
[0006] In the field of lighting technology LEDs are normally used in lamps or lighting apparatuses
that include a plurality of LED light sources and corresponding lighting bodies that
can comprise a waveguide or reflector of the light beam produced by the LED and a
lens crossed by such a light beam.
[0007] Lighting apparatuses of various shapes and sizes are known in which the aforementioned
LED light sources and the corresponding lighting bodies are suitably positioned and
orientated to obtain a predetermined size of lit area or else a predetermined lighting
intensity. It is also known to equip these lighting apparatuses with groups of LED
light sources having different lighting powers to one another.
[0008] It is also worth noting that increases in lighting intensity normally involve corresponding
increases in the electrical power consumed.
[0009] Whilst advantageous from various points of view, and substantially achieving their
purpose, these lighting apparatuses still have some drawbacks that limit their widespread
use.
[0010] Firstly, the intensity of the light beam generated by the LED sources and by the
corresponding diffusing lighting bodies is not yet satisfactory in terms of energy
efficiency and of size of area lit. More specifically, the transparent support legs
of the diffusing lighting bodies associated with each LED take away part of the light
beam generated.
[0011] Secondly, the standard thermal operating conditions of LED lighting apparatuses is
close to 70° on the lighting body and it is obviously at an even higher temperature
on the LED source reducing the overall useful life of the source. These relatively
high standard thermal conditions also oblige the use of metal casings and supports
for such lighting apparatuses.
[0012] Finally, the drawback remains that the possible increase in lighting area or radius
is paid for by an increase in the electrical power used.
[0013] The technical problem forming the basis of the present invention is to device a new
structure of LED lighting electric device having structural and functional characteristics
such as to overcome the aforementioned drawbacks with reference to the prior art.
Summary of the invention
[0014] The technical problem is solved by an LED lighting electric device of the type indicated
previously and
characterised in that a resin that does not absorb light radiation is used in contact with the base ends
of the transparent support legs of the lighting body acting as diffuser, so as to
obtain a saturation of the light beam inside such transparent legs with a corresponding
increase in the light intensity emitted by the LED device for the same electrical
power consumed
[0015] Advantageously, the aforementioned resin is a silicon epoxy resin with high heat
conduction. In this way there is the further advantage that part of the heat produced
by the LED light source is taken away through the silicon resin reducing the standard
thermal conditions of the lighting device.
[0016] Other characteristics and advantages of the LED lighting electric device according
to the present invention shall become clearer from the following description of an
example embodiment thereof, given for indicating and not limiting purposes with reference
to the attached drawings.
In such drawings:
Brief description of the drawings
[0017]
- figure 1 shows a perspective and schematic view of an LED electric device according
to the present invention;
- figure 2 shows a perspective and partial section view of a detail of the lighting
device according to the invention;
- figure 3 shows a perspective view of the framework of a lighting apparatus including
a plurality of LED lighting devices according to the present invention;
- figures 4 and 5 show respective schematic views from above, and from the side of the
framework of figure 3;
- figures 6 and 7 show respective perspective views from above and from the side of
a detail of the lighting apparatus of figure 3;
- figure 8 shows a perspective view of a lighting apparatus obtained in accordance with
the present invention.
Detailed description
[0018] With reference to such drawings, an LED lighting electric device made according to
the present invention is globally and schematically indicated with 1.
[0019] The device 1 can also be defined as an LED lamp associated with a diffusing optical
element of the light beam produced by the lamp.
[0020] The device 1 is particularly suitable for being used in the field of civil or industrial
lighting technology. In other words bulbs or lights including a plurality of devices
1 can be installed inside or outside, i.e. indoors or outdoors, in homes, offices,
shops or warehouses, or else they can be used for public uses like for example street
lighting or lighting for public places in general (gyms, schools, hospitals, etc.).
[0021] The LED lighting electric device 1 comprising at least one LED (Light Emitter Diode)
light source 2 based upon a light emitting semiconductor diode.
[0022] The specific type of LED light source 2 is not covered by the present invention in
the sense that the source 2 can be a single diode or a multichip LED formed from at
least three diodes.
[0023] For example, leds are available in a very wide range of "pure" colours, i.e. obtained
without the use of filters placed in front of the light source and emitted "naturally"
by the led itself. Multichip leds, on the other hand, are formed from three diodes
- a red one, a blue one and a green one - that when suitably controlled can create
thousands of colour combinations.
[0024] For the purposes of the present invention what counts is exclusively that the device
1 comprises at least one LED light source 2 mounted and powered on a support plate
15.
[0025] It is commonly said that the LED is a primary optical system that is mounted on a
primary reflector, for example a metallic layer, which is fixedly connected to a printed
circuit board.
[0026] The LED light source 2 has an associated waveguide 3 that acts as a diffusing lighting
body intended to transmit, direct and diffuse the light beam generated by the light
source 2.
[0027] The waveguide 3 has an essentially inverted truncated cone shaped structure extending
with the smaller base at the LED light source 2 and the larger base distal from the
LED source 2.
[0028] The larger base is substantially formed from an optical element intended to interact
with a light beam emitted by the LED.
[0029] In other words, the larger base of the waveguide 3 comprises a lens 4 arranged in
a predetermined spaced apart relationship from the LED light source 2 in a position
substantially perpendicular to the main lighting direction of the light source 2.
[0030] The lens 4 allows the light beam emitted by the LED light source 2 to be focused
keeping it within a predetermined emission angle with the minimum dispersion.
[0031] The inverted truncated cone shape of the waveguide 3 has the function of directing
and diffusing the light beam emitted by the LED onto the lens 4 operating substantially
as a diffusing body of the light beam.
[0032] To keep the waveguide 3 in position transparent support legs 5 are provided formed
in one piece with the waveguide and extending around said light source 2. In some
other embodiments the legs 5 are formed in one piece around the perimeter of the lens
4.
[0033] More specifically, there are four of such legs 5 and they extend parallel to one
another around the light source 2. The legs 5 are arranged in equally angularly spaced
position, 90° apart, around the waveguide 3.
[0034] Therefore, the legs 5 have an end formed in one piece with the waveguide 3, at the
lens 4, and have the opposite base or foot ends fixedly connected to the support plate
15 of the light source 2.
[0035] Even more specifically, the legs 5 are small cylindrical transparent columns, slightly
tapered towards their base, and having a base end portion 7 fixed to the support card
15 around the light source 2.
[0036] The base end portions 7 have a smaller diameter than the average diameter of the
column-shaped legs 5 to each be inserted with pressure in a corresponding hole 8 formed
in the plate 15 around the light source 2.
[0037] In the example embodiment described here purely for indicative and not limiting purpose,
there are four holes 8 arranged with an angular spacing of 90° around the light source
2, as if they were the vertices of a square running around said light source 2.
[0038] The waveguide 3 and the corresponding support legs 5, formed in one piece, are made
from a transparent synthetic plastic material, for example a polycarbonate.
[0039] The lens 4 can also be formed in one piece with the waveguide 3 as larger base of
the truncated cone shaped body.
[0040] Alternatively, the lens 4 can be fixedly connected as the larger base of the waveguide
3 shaped like a truncated cone.
[0041] Again alternatively, the lens 4 may be missing.
[0042] The lens 4 can be simply a transparent layer, in the shape of a circular crown with
a central through hole.
[0043] The lens 4 can also have a more complex structure, for example with a pair of surfaces
arranged parallel to one another a predetermined distance apart, a flat surface facing
towards the light source 2 and another prism shaped outer surface.
[0044] By prism shaped surface we mean to define a surface that has a plurality of prism
shaped elements adjacent to one another and equipped with inclined portions 4a or
facetings 4b such as to be able to create phenomena of reflection, refraction, diffraction
or polarisation of the light beam that passes through the lens 4.
[0045] The aforementioned prism shaped elements can be right pyramids or frustums of right
pyramid brought close together and having the base parallel to the first flat surface.
[0046] Advantageously, according to the present invention, the base ends 7 of said legs
5 are in contact with a resin 9 that does not absorb light radiation.
[0047] For the purposes of the present invention it is sufficient that the ends of the legs
5 be covered or in any case darkened by the resin 9 so that the light radiation channelling
along the small transparent columns is unable to leave by the base.
[0048] Preferably, however, the base ends 7 of the legs 5 are embedded in the resin 9 on
the opposite side of the plate 15 with respect to where the light source 2 is located.
[0049] The resin 9 is a silicon resin that is a good heat conductor.
[0050] Advantageously, moreover, the resin 9 is an epoxy resin that lends itself to being
shaped through injection moulding.
[0051] Purely as a non-limiting example we point out that the resin 9 can be of the type
commercially known by the trade name FT0610 that defines a specific resin for insulating,
sealing and protecting electrical transformers.
[0052] The low exothermy of this resin avoids damaging the components during polymerisation
thanks to the low heat production. Moreover, this epoxy resin FT0610, offers excellent
heat dissipation.
[0053] The high dielectric, mechanical, physical and chemical characteristics of this resin
give the components coated with it total protection against humidity and chemical
agents.
[0054] The presence of the resin 9 on the base ends 7 of the transparent support legs 5
of the waveguide 3 allows the light radiation emitted by the source 2 and diffused
by the waveguide 3 not to be attenuated or damped in its intensity by the presence
of the transparent legs 5.
[0055] The phenomenon that occurs in the device according to the present invention is relatively
complex and we can define it as light "saturation".
[0056] Basically, the light beam that crosses the legs 5 in the opposite direction, i.e.
in the direction of the source, with respect to the desired and main direction of
emission of the beam itself, finds its path blocked by the silicon resin 9.
[0057] It is as if each of the legs 5 were in a situation of saturation of the light beam
with the result that none of them any longer absorbs part of the light beam produced
by the source 2.
[0058] Thus, unlike what currently occurs for the solutions of the prior art, the transparent
support legs 5 of the waveguide 3 do not in any way take away light from the main
light beam emitted by the source 2 and do not contribute to reducing the light intensity
of the source 2.
[0059] To use a plumbing analogy, it is as if there was a main pipe carrying a fluid that
has branches along which the fluid finds its path blocked. In this case the branches
could not in any way contribute to taking fluid away from the main pipe.
[0060] By analogy, the light beam that passes through each of the transparent legs 5 has
no way to pass or be absorbed at the ends thereof located near to the source 2 and
it reaches a state of saturation that prevents other arriving light from passing back
through the small transparent column.
[0061] In other words, the electromagnetic light wave that passes through the transparent
support legs 5 of the waveguide 3 reaches the ends 7 coated with resin 9 and saturates
the corresponding transparent leg with light.
[0062] Tests carried out by the Applicant have demonstrated that the light intensity of
the device according to the invention is surprisingly increased by 40% and more compared
to the same device made according to the prior art placed in the same operating conditions.
[0063] This configuration of the device 1 according to the invention achieves a further
important advantage represented by the fact that the silicon resin 9 takes away the
heat produced at the base of the LED light source 2 and thus allows full performance
operating conditions to be reached that substantially coincide with those theoretically
foreseen for the regular and correct operation of a semiconductor LED.
[0064] With the device according to the invention the operating temperature at the base
of the LED is around 45°C whereas that of the light source is around 70°C, which represents
the optimal theoretical combination of operation for a semiconductor LED.
[0065] This gives the great advantage that the LED device according to the invention can
operate for a period that substantially coincides with the theoretical operating time
equal to 100,000 hours.
[0066] It can therefore be understood how important and far-reaching the present invention
is, making it possible to provide an LED lighting electric device in which the totality
of the light beam emitted by the source is exploited and directed for lighting purposes
whilst, at the same time, the light source is kept at a regular operating temperature
foreseen by the theoretical specifications of semiconductor LEDs.
[0067] It follows from this that with the lighting devices according to the invention it
is possible to obtain better optical performance, an increase in luminosity of the
source and a reduction in the standard thermal conditions, if compared with the devices
currently proposed by the prior art.
[0068] The LED lighting electric device according to the invention can be used to make LED
headlights or lamps in general by associating them together and feeding power, for
example in parallel, to a plurality of devices 1 in the same lighting apparatus.
[0069] An example of application of a plurality of devices made in accordance with the present
invention and mounted on a headlight for use on the road shall now be described.
[0070] Of course, there is no reason why various types of lighting apparatuses should not
be made, for example by associating or combining a plurality of devices 1 in order
to obtain lighting apparatuses for indoor or outdoor uses, both for public or private
use.
[0071] For indicative but not limiting purpose, figure 3 schematically illustrates a lighting
apparatus 10 including a plurality of LED lighting electric devices 1 according to
the present invention.
[0072] The apparatus 10 is substantially a headlight having an essentially open truncated
cone shaped framework 11 with the smaller base 13 plate-shaped and substantially round
and the larger base 14 open to give access to an inner cavity 12 in which the lighting
devices 1 are housed, to all face towards an area to be lit when the apparatus 10
is installed.
[0073] Alternatively, the apparatus 10 can be made through a parabola or spherical cap-shaped
framework in which the LED lighting devices are mounted in the concavity of the parabola
or of the spherical cap.
[0074] For the purposes of the present invention the shape of the framework of the lighting
apparatus can be whatever; what cunts is that the lighting devices can be mounted
in the cavity 12 of the framework of the lighting apparatus with the electrical connections
going to each light source 2 arranged on the opposite side with respect to the cavity
12, in other words on the outer surface of the framework 11.
[0075] In the example embodiment described here for indicating and not limiting purposes,
the outer surface of the framework 11 comprises a plurality of plate-shaped portions
16, essentially shaped like an elongated isosceles trapezium, adjacent to one another
along a longer oblique side of the trapezium shape to form, as a plurality of trapezium
shaped sectors, the inclined or oblique walls of the truncated cone shape and all
joined in their shorter round base side 13 of the truncated cone shaped framework
11.
[0076] There can be sixteen or twenty portions 16 according to the configuration requirements
of the framework 11, both in terms of area covered, and in terms of inclination of
the oblique side wall. However, there is no reason why a greater or smaller number
of portions 16 should not be used, just as there is nothing to stop such portions
16 being suitably sized so as to modulate the size of their larger and smaller bases
and of the oblique sides.
[0077] The larger base sides of the trapezium shaped portions 16 are joined with an annular
edge portion 17 of the lighting apparatus 10.
[0078] Conventional fastening means 18 to hang or fasten the lighting apparatus 10 to a
support or to a wall or ceiling are provided on such an annular edge 17.
[0079] Advantageously, according to the invention, in the cavity 12 of the lighting apparatus
10 the portions 16 are intended to house a plurality of LED lighting devices 1, arranged
in an orderly fashion.
[0080] The surface facing towards the cavity 12 of the round smaller base 13 of the framework
11 is in turn also intended to receive a predetermined group of LED lighting devices
1.
[0081] In particular, the smaller base 13 is structured substantially like the support card
15 of the light source 2, in the sense that some light sources 2 are mounted and fed
with power on it, associated with the respective waveguides 3.
[0082] Each light source 2 is encircled by a group of through holes 8 through the base 13
and intended to receive the respective base ends 7 of the support legs 5 of each waveguide
3.
[0083] Around each light source there are preferably four holes 8, angularly spaced apart
by 90°, each intended to receive, by coupling or by pressure, a corresponding base
end 7 of a transparent leg 5.
[0084] Outside of the framework 11, in other words on the opposite side to the cavity 12
in which the lighting devices 1 are housed, it is possible to see the holes 8 for
housing the base ends 7 and that cross both the smaller base 13 and the portions 16
that form the oblique walls of the framework 11.
[0085] These holes 8 are identifiable or groupable in homogeneous groups 20 of four holes
each, corresponding to the support legs 5 of the same waveguide 3 associated with
a given light source 2.
[0086] Each sector 16 has at least six groups 20 of four holes, whereas the smaller base
13 has ten groups 20 of four holes.
[0087] So, each group 20 of four holes is defined by a side wall 21 for containing said
silicon epoxy resin.
[0088] The side walls 21 form substantially a square edge around the holes 8 associated
with the support legs 5 of the waveguide 3 of each LED lighting device 1.
[0089] In other words, on the rear of the support plate of each light source 2, a plate
that can be represented by the smaller base 13 or by any of the portions 16 with trapezium
shaped sector, side walls 21 for containing the silicon resin placed in contact with
the base ends 7 of the supports of the waveguides 3 are foreseen.
[0090] The resin that does not absorb light radiation through injection moulding occupies
the space enclosed and defined by the quadrangular side walls 21. The injection is
carried out according to
per sé conventional ways.
[0091] In this way, the base ends 7 of the legs 7, forcibly inserted into the holes 8 and
projecting on the rear of the support plates, be they 13 or 16, are coated and substantially
embedded inside the layer of resin that has occupied each square portions defined
by the side walls 21.
[0092] In this way the resin is associated with each lighting device 1 without wastage and
avoiding the entire framework 11 being covered by an excessively expensive casting
of resin that is of little use in the areas where it is not necessary.
[0093] The method for making the lighting apparatus 10 substantially coincides with the
method for making even just one of the LED lighting electric devices 1.
[0094] Basically, on the rear of the support plate 15 of the light source 2 a layer of resin
that does not absorb light radiation is deposited.
[0095] Since the silicon resin is an epoxy resin, it lends itself to being deposited through
an injection moulding technique that can cover the rest of the support plate 15 or
a portion thereof, for example a portion that through the side wall 21 defines a homogeneous
group of holes 8 through which the base ends 7 of the support legs 5 of the waveguide
3 are fixed.
[0096] Thus the lighting device 1 according to the invention can be made with relatively
small investments by providing side walls for containing the resin associated with
each lighting device on the rear of the support plate of the corresponding LED light
source.
[0097] The epoxy resin that is injected into the areas defined by the side walls 21 contributes
to firmly fixing the support legs of the waveguides 3 and also covers the electrical
connections that go to each semiconductor LED of each light source 2.
[0098] The end result is a lighting apparatus 10 of any shape and size in which each LED
lighting device 1 has been fixedly connected with the lighting apparatus and, at the
same time, takes advantage of the heat dissipating effect carried out by the silicon
epoxy resin that greatly contributes to keeping a constant and optimal standard thermal
conditions during operation, in other words while the lamp is on.
1. LED lighting electric device (1) comprising:
- an LED light source (2) mounted and powered on a support card (15);
- a corresponding inverted truncated cone-shaped waveguide (3) associated with the
light source (2) to diffuse the light beam generated by said source;
- a lens (4) supported in a predetermined spaced apart relationship with said light
source (2);
- transparent support legs (5) formed in one piece with the waveguide (3) and base
ends (7) proximal to the light source (2) fixed to said card (15) around the light
source (2);
characterised in that said base ends (7) of said transparent legs (5) are in contact with a resin (9) that
does not absorb light radiation.
2. Device according to claim 1, characterised in that said resin is a silicon epoxy resin.
3. Device according to claim 2, characterised in that said silicon resin is a heat conductor.
4. Device according to claim 1, characterised in that said base ends (7) are embedded in said resin (9).
5. Device according to claim 1, characterised in that said legs (5) extend parallel to one another around said light source (2).
6. Device according to claim 1, characterised in that said base ends (7) of the legs (5) have a reduced diameter compared to the diameter
of the corresponding legs (5) each to be forcibly inserted in a corresponding hole
(8) formed in said plate around said light source (2).
7. Device according to claim 1, characterised in that
8. Lighting apparatus (10) of the type comprising a support framework (11) for a plurality
of LED lighting electric devices (1) each of which is structured according to claim
1.
9. Lighting apparatus (10) according to claim 8, characterised in that said framework (11) is structured like an open truncated cone with the larger base
open to give access to an inner cavity (12) in which the lighting devices (1) are
housed on at least one plurality of plate-shaped portions (16) with trapezoidal sector
associated together to form the inclined wall of the truncated cone; a side wall (21)
for containing said resin (9) being provided on the opposite surface of each plate-shaped
portion (16) with at least one device present.
10. Lighting apparatus (10) according to claim 9, characterised in that said side wall (21) defines a group (20) of through holes (8) formed in said plate-shaped
portion (16) and receiving the base ends (7) of corresponding support legs (5) of
the waveguide (3) of one of said LED lighting devices (1).
11. Method for making an LED lighting electric device comprising:
- an LED light source (2) mounted and powered on a support card (15);
- a corresponding inverted truncated cone-shaped waveguide (3) associated with the
light source (2) to diffuse the light beam generated by said source;
- a lens (4) supported in a predetermined spaced apart relationship with said light
source (2);
- transparent support legs (5) formed in one piece with the waveguide (3) and base
ends (7) proximal to the light source (2) fixed to said card (15) by means of through
holes (8) in said card (15) around the light source (2);
characterised in that a side wall (21) is provided defining said holes (8) on the side of said card (15)
opposite said waveguide (3) and injecting into the area defined by said side wall
a resin (9) that does not absorb light radiation that is in contact with the base
ends (7) of said legs (5).