FIELD OF THE INVENTION
[0001] The invention relates to lighting devices comprising a puck assembly comprising a
plurality of LEDs and a cover element, the cover element comprising an inner shell
element, and an outer shell element which is transparent or translucent.
BACKGROUND OF THE INVENTION
[0002] US 8,596,827 describes a lamp comprising an outer bulb, an inner optical processing member, a
heat sink in which the outer bulb and the inner optical processing member are mounted
and a plurality of LEDs mounted on a heat pipe and arranged in the inner optical processing
member.
[0003] Such LED based solutions are however quite inefficient. The heat that is generated
during operation generally leads to temperatures in the application that deteriorate
the system efficacy and limit the lifetime of the LEDs and other components. In order
to transfer heat to the ambient such LED devices generally use a heat sink. In most
LED applications the heat sink and the light emitting surface are two separate elements.
The size of the heat sink is smaller than the total lamp enclosure, limiting the heat
transfer to the ambient and thus limiting the thermal performance.
[0004] Some LED based solutions enable the total enclosure to be heated, leading to an effective
heat transfer to the ambient, e.g. by distributing the LEDs over the outer enclosure.
Distributing the LEDs over a 3D curved outer enclosure leads to complex and expensive
solutions, while the use of flat surfaces lead to deviating shapes of the lamp or
luminaire.
[0005] Other LED based solutions, e.g. so-called Inca bulbs, have LEDs placed inside a transparent
or translucent container and a special gas is used to enhance the internal heat transfer
from the LED source(s) to the enclosure. This however leads to an LED degradation
that can only be solved by adding a certain amount of oxygen, which in turn leads
to an impaired thermal performance. Also, making such a bulb is critical in assembly
due to the high temperatures at which the glass is processed, e.g. bulb sealing and
annealing. These high temperatures during sealing also limit the amount of the special
gas that can be pumped into the bulb.
[0006] Thus, there is a desire for providing a LED lighting device which is more efficient
in regards of heat transfer from the LEDs to the surroundings, which provides for
a longer lifetime of the LEDs and which has a simpler structure and thus is less costly
to manufacture and assemble.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to overcome this problem, and to provide
a lighting device which is more efficient in regards of heat transfer from the LEDs
to the surroundings, which provides for a longer lifetime and an improved power/light
output of the LEDs and which is structurally simpler and thus less costly to manufacture
and assemble.
[0008] According to a first aspect of the invention, this and other objects are achieved
by means of a lighting device comprising a puck assembly comprising a plurality of
LEDs and a cover element comprising an outer shell element adapted for forming a light
exit surface of the lighting device and an inner shell element, the outer shell element
and the inner shell element forming together a hermetically sealed gas chamber, the
hermetically sealed gas chamber being filled with substantially one single gas adapted
for functioning as a heat transferring medium for transferring heat from the puck
assembly towards the outer shell element, and the inner shell element forming a cavity
adapted for accommodating the puck assembly at least partially in such a way that
the puck assembly is arranged outside the hermetically sealed gas chamber in a heat
transferring relationship with the inner shell element and thereby with the substantially
one single gas provided in the hermetically sealed gas chamber.
[0009] By providing the outer shell element and the inner shell element forming together
one hermetically sealed gas chamber, a lighting device with a cover element having
a particularly simple construction being particularly simple to manufacture is provided.
[0010] By providing the hermetically sealed gas chamber as being filled with substantially
one single gas adapted for functioning as a heat transferring medium for transferring
heat from the puck assembly towards the outer shell element, a lighting device which
is very effective in regards of heat transfer from the LEDs to the surroundings is
provided.
[0011] By providing the inner shell element forming a cavity adapted for accommodating the
puck assembly at least partially in such a way that the puck assembly is arranged
outside the hermetically sealed gas chamber in a heat transferring relationship with
the inner shell element and thereby with the substantially one single gas provided
in the hermetically sealed gas chamber, a lighting device which is very effective
in regards of heat transfer from the LEDs to the surroundings is provided.
[0012] Furthermore, a lighting device with a generally simpler structure is provided for
as the heat sink and the light exit surface is thus formed by one single element,
namely the cover element.
[0013] In prior art light bulbs, such as an INCA bulb, the bulb acts a closed chemical reaction
chamber, and thus reaction products stay inside the bulb and there is no refreshment
of oxygen. This lack of oxygen has deteriorating effects on the LEDs. FurthermoreHence,
as the plurality of LEDs are arranged outside of the hermetically sealed gas chamber,
a lighting device is provided in which the plurality of LEDs are not in direct contact
with the ambientsubstantially one single gas provided in the hermetically sealed gas
chamber and in which the oxygen in the air in the vicinity of the LEDs may be refreshed.
The LEDs are thus not subjected to deteriorating effects of the one single gasrelated
to lack of oxygen. This in turn provides for a lighting device in which the LEDs have
a longer lifetime and an improved power/light output.
[0014] Furthermore, with such a lighting device the arrangement of the plurality of LEDs
may be placed at the outside of the cover element and thus the hermetically sealed
gas chamber, thereby makesing both manufacture and particularly assembly easy. The
same outer and inner shell elements form both an optical element of the LED lamp or
luminaire to distribute the light all around or directionally and a mechanical enclosure
or cover element of the plurality of LEDs. Thus such a lighting device is also particularly
simple both in structure and to assemble and thus less costly to manufacture and assemble.
[0015] In an embodiment the outer shell element and the inner shell element forming together
the hermetically sealed gas chamber are made of a glass or a ceramic and are manufactured
as a separate part in one piece using a high temperature glass or ceramics processing
method.
[0016] Thereby a lighting device is provided in which the outer and inner shell element
may be manufactured on existing production lines and may be assembled with a puck
assembly to form a lighting device under normal ambient temperature conditions. Particularly,
the outer and inner shell element may be manufactured as a separate part, allowing
the full use of glass or ceramics processing like heating in an oven (e.g. to 400
°C) to remove (organic) contamination, vacuum pumping, and filling with the one single
gas and subsequent hermetic sealing, i.e. "tipping", by glass processing. Similarly
the wick materials can be chosen to be compatible with the working fluid. Thus, such
a lighting device is also particularly simple both in structure and to assemble and
thus less costly to manufacture and assemble.
[0017] In an embodiment a transition between the outer shell element and the inner shell
element is formed as a continuous transition.
[0018] Thereby a lighting device is provided which is particularly simple in structure and
thus less costly to manufacture, and which furthermore is particularly suitable for
holding the one single gas within the hermetically sealed gas chamber.
[0019] In an embodiment the outer shell element and the inner shell element form together
a hermetically sealed gas chamber, the hermetically sealed gas chamber being filled
with substantially one single gas adapted for functioning as a heat transferring medium
for transferring heat from the puck assembly towards substantially all of the surface
of the outer shell element.
[0020] In an embodiment the inner shell element comprises a surface element extending through
at least a part of the puck assembly, the surface element forming a cavity forming
part of the hermetically sealed gas chamber.
[0021] Thereby a lighting device is provided which has an enlarged contact surface area
between the puck assembly and the inner shell element and therefore is particularly
efficient in regards of heat transfer from the puck assembly to the hermetically sealed
gas chamber and thus eventually to the surroundings.
[0022] In an embodiment the lighting device, the surface element of the inner shell element
extends centrally through at least a part of the puck assembly in a substantially
longitudinal direction of the puck assembly.
[0023] Thereby a lighting device is provided which has a particularly large contact surface
area between the puck assembly and the inner shell element and therefore is particularly
efficient in regards of heat transfer from the puck assembly to the hermetically sealed
gas chamber and thus eventually to the surroundings.
[0024] Thereby a lighting device is provided in which the surface area used for heat transfer
to the surroundings is optimized and which is thus particularly efficient in regards
of heat transfer from the LEDs to the surroundings.
[0025] In an embodiment the puck assembly comprises a heat spreading element arranged in
heat transferring relationship with the plurality of LEDs and with the inner shell
element in an assembled condition of the lighting device.
[0026] Thereby a lighting device is provided in which is particularly efficient in regards
of heat transfer from the LEDs to the hermetically sealed gas chamber and thus eventually
to the surroundings.
[0027] In an embodiment the puck assembly comprises a driver element adapted for driving
the plurality of LEDs and a driver element insulator, the driver element insulator
being arranged such as to heat insulate the driver element from the heat spreading
element in an assembled condition of the puck assembly.
[0028] Thereby a lighting device is provided in which the driver element is shielded from
the heat generated by the plurality of LEDs and thus is provided with a prolonged
lifetime and enlarged operational reliability.
[0029] In an embodiment the lighting device further comprising a shrink sleeve made of a
Thermal Interface Material, TIM, and being adapted for extending between at least
a part of the puck assembly and the inner shell element in an assembled condition
of the lighting device.
[0030] Thereby a lighting device is provided in which is particularly efficient in regards
of heat transfer from the puck assembly to the inner shell element, and therefore
on to the hermetically sealed gas chamber and thus eventually to the surroundings.
[0031] In an embodiment the puck assembly comprises a cover element arranged such as to
extend over the plurality of LEDs in an assembled condition of the puck assembly.
[0032] Thereby a lighting device is provided in which the plurality of LEDs are shielded
towards the surroundings such as to avoid deterioration of the plurality of LEDs and/or
the intensity of the light emitted due to outside influences such as impurities or
the like, to which the plurality of LEDs may be exposed during or after assembly of
the lighting device.
[0033] The puck assembly may furthermore comprise an electrical connection element.
[0034] In an embodiment the puck assembly comprises a spring bush adapted for applying a
constant pressure to the plurality of LEDs, the spring bush comprising a rim adapted
for alignment of the plurality of LEDs and the heat transferring element in the assembled
condition of the puck assembly.
[0035] Thereby a lighting device is provided with which it is particularly simple to obtain
correct alignment of the plurality of LEDs and the heat transferring element when
assembling the puck assembly and subsequently the lighting device. Such a lighting
device is thus particularly simple to assemble and thus also less costly to assemble.
[0036] In an embodiment the puck assembly is in an assembled condition of the lighting device
attached to the inner shell element by means of thermally conductive glue.
[0037] Thereby a lighting device is provided in which is particularly efficient in regards
of heat transfer from the puck assembly, and in particular from the heat spreading
element of the puck assembly, to the hermetically sealed gas chamber and thus eventually
to the surroundings. Furthermore, a particularly durable lighting device is provided
for.
[0038] In an embodiment the plurality of LEDs are arranged on a base, the base being arranged
such that the plurality of LEDs are arranged in a horizontal or vertical alignment.
[0039] Thereby a lighting device is provided which has a high versatility in terms of arrangement
of the plurality of LEDs and thus in light pattern.
[0040] In an embodiment the substantially one single gas is helium, helium having particularly
good heat transferring capabilities and thus being a particularly well functioning
medium for transferring heat from the puck assembly towards the outer shell element.
[0041] The invention furthermore concerns a lamp, luminaire or system comprising a light
emitting device according to any one of the previous claims and being used in one
or more of the following applications: consumer lamps or luminaires, professional
lamps or luminaires, street lighting, underwater lighting and lighting in extreme
environments. It is noted that the invention relates to all possible combinations
of features recited in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] This and other aspects of the present invention will now be described in more detail,
with reference to the appended drawings showing embodiment(s) of the invention.
Fig. 1 shows a cross sectional side view of a lighting device according to a first
embodiment of the invention in an assembled condition.
Fig. 2 shows a perspective sectional view of a lighting device according to Fig. 1.
Fig. 3 shows a cross sectional side view of a lighting device according to a second
embodiment of the invention in an assembled condition.
Fig. 4 shows a perspective exploded view of a puck assembly of a lighting device according
to Fig. 1 or Fig. 2.
Fig. 5 shows a perspective exploded view of a lighting device according to any of
Fig. 1 or Fig. 2 with the puck assembly in an assembled condition.
Fig. 6 shows a perspective side view of a lighting device according to a third embodiment
of the invention in an assembled condition.
Fig. 7 shows a perspective exploded view of a lighting device according to Fig. 6.
[0043] As illustrated in the figures, the sizes of layers and regions are exaggerated for
illustrative purposes and, thus, are provided to illustrate the general structures
of embodiments of the present invention. Like reference numerals refer to like elements
throughout.
DETAILED DESCRIPTION
[0044] The present invention will now be described more fully hereinafter with reference
to the accompanying drawings, in which currently preferred embodiments of the invention
are shown. This invention may, however, be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein; rather, these embodiments
are provided for thoroughness and completeness, and fully convey the scope of the
invention to the skilled person.
[0045] Fig. 1 shows a cross sectional side view of a lighting device 1 according to a first
embodiment of the invention. The lighting device 1 generally comprises a puck assembly
2 and a cover element. The cover element comprises an inner shell element 3 and an
outer shell element 4.
[0046] The outer shell element 4 comprises an inner surface 41 and an outer surface 42 and
is adapted for forming a light exit surface of the lighting device 1 such that light
is emitted from the lighting device at the outer surface 42. The outer shell element
4 may be shaped in any feasible manner, such as to form lighting devices having any
desired outer shape, including but not limited to for example incandescent lighting
devices and candle lighting devices. The outer shell element 4 is transparent or translucent.
The outer shell element 4 may be made of glass or a suitable ceramic.
[0047] The inner shell element 3 forms a cavity 31 adapted for accommodating the puck assembly
2 at least partially. The inner shell element 3 comprises an inner surface 32 and
an outer surface 33. In the assembled condition of the lighting device 1, the puck
assembly 2 is in thermal contact with the inner surface 32 of the inner shell element
3 and thus with the inner shell element 3 in general.
[0048] As may be seen on Fig. 1 at least an electrical connection member 6 of the puck assembly
2 extends outside of the cavity 31. Apart from that, the inner shell element 3 may
be shaped in any feasible manner. The inner shell element 3 is transparent or translucent.
The inner shell element 3 may be made of glass or a suitable ceramic and is made of
the same material as the outer shell element 4.
[0049] As may also be seen on Fig. 1, in the assembled condition of the lighting device
1 a space or distance is provided between the plurality of LEDs 11 and the inner surface
32 of the inner shell element 3 and/or between the cover element 13 and the inner
surface 32 of the inner shell element 3.
[0050] The outer shell element 4 and the inner shell element 3 form together a hermetically
sealed gas chamber 5 filled with substantially one single gas. The one single gas
is adapted for functioning as a heat transferring medium for transferring heat from
the puck assembly 2 towards the outer shell element 4 in a manner to be described
further below. The one single gas is in one embodiment Helium. In other embodiments
the one single gas may be Hydrogen or Neon. The outer surface 33 of the inner shell
element 3 and the inner surface 41 of the outer shell element 4 are in thermal contact
with the one single gas in the hermetically sealed gas chamber 5.
[0051] The outer shell element 4 and the inner shell element 3 are manufactured as a separate
part in one piece using a high temperature glass or ceramics processing method. Thus,
the transition 43 between the outer shell element 4 and the inner shell element 3
is a continuous transition.
[0052] Alternatively, it may be feasible to manufacture the outer shell element 4 and the
inner shell element 3 as a separate part in two pieces using a high temperature glass
or ceramics processing method. In this case, the outer shell element 4 and the inner
shell element 3 are assembled to form one separate part before assembling the lighting
device 1 in such a way that the transition 43 between the outer shell element 4 and
the inner shell element 3 is a continuous transition.
[0053] Furthermore, the substantially one single gas with which the hermetically sealed
gas chamber is filled is adapted for functioning as a heat transferring medium for
transferring heat from the puck assembly towards substantially all of the surface
of the outer shell element.
[0054] In the embodiment shown in Figs. 1 and 2, the inner shell element 3 comprises a surface
element 34 extending through at least a part of the puck assembly 2 in the assembled
condition of the lighting device 1. The surface element 34 forms or comprises a cavity
51. The cavity 51 forms a part of the hermetically sealed gas chamber 5 and is in
direct fluid contact with the hermetically sealed gas chamber 5. Thus the cavity 51
is also filled with the substantially one ingle gas. In the embodiment shown, in the
assembled condition of the lighting device 1, the surface element 34 of the inner
shell element 3 extends centrally through the puck assembly 2 in a substantially longitudinal
direction of the puck assembly 2. The surface element 34 forms a further contact surface
with the puck assembly 2 in an assembled condition of the lighting device 1.
[0055] The surface element 34 is, however, an optional element. Fig. 3 thus illustrates
a second embodiment of a lighting device 100 according to the invention in which the
surface element 34 is omitted.
[0056] Referring again to Fig. 1, as the puck assembly 2 is arranged in the cavity 31 formed
by the inner shell element 3, the puck assembly 2 is arranged outside the hermetically
sealed gas chamber 5. Furthermore, the puck assembly 2 is arranged in a heat transferring
relationship with the inner shell element 3 and thereby with the substantially one
single gas provided in the hermetically sealed gas chamber 5. The materials used for
the various components of the puck assembly 2 may be chosen to be compatible with
the working fluid.
[0057] Referring also to Fig. 4, showing an exploded view of a puck assembly 2, the puck
assembly 2 generally comprises a plurality of LEDs 11, an optional base 12 on which
the plurality of LEDs 11 are arranged, a shrink sleeve 14, a heat transferring element
9, an insulator 8, a driver element 7 and an electrical connection member 6.
[0058] The puck assembly 2 may furthermore optionally comprise a cover element 13 adapted
for covering the plurality of LEDs 11. The cover element 13 is transparent and shields
the plurality of LEDs 11 from the outside against for example dirt and other potentially
detrimental influences, such as to increase the life time of the plurality of LEDs
11.
[0059] The plurality LEDs 11 are adapted for, in operation, emitting light, which may be
of any desired color. In one embodiment the plurality LEDs 11 are adapted for, in
operation, emitting white light. In the embodiments shown in Figs. 1 to 5, the plurality
of LEDs 11 and where present the base 12 are mounted in the puck assembly 2 such a
way that the plurality of LEDs 11 are oriented in a substantially horizontal position,
i.e. in a position perpendicular to the longitudinal extension (illustrated by means
of the dash-dotted line shown in Fig. 1 and 2) of the puck assembly 2.
[0060] The base 12 carries the plurality of LEDs 11, and may be any suitable type of base,
such as for example a printed circuit board.
[0061] The heat transferring element 9 is adapted for transferring heat generated by the
plurality of LEDs 11 towards the inner shell element 3 in the assembled condition
of the lighting device. The heat transferring element 9 is made of a material with
good heat conductive characteristics, such as for example a metal.
[0062] The insulator 8 is adapted for, in the assembled condition of the puck assembly 2,
insulating the driver element 7 from the heat transferring element 9, and thus from
the heat generated by the plurality of LEDs 11. The insulator 8 is thus made of a
heat insulating material.
[0063] The driver element 7 may be any driver element suitable for driving the plurality
of LEDs to emit light in a suitable and desired manner.
[0064] The electrical connection member 6 may be any electrical connection member suitable
for connecting the lighting device 1 to a source of electrical energy. Typically,
the electrical connection member 6 is a socket. In an alternative, the electrical
connection member 6 is a terminal.
[0065] The puck assembly 2 further comprises a shrink sleeve 14. The shrink sleeve 14 is
adapted to function as an expandable thermal interface material and acts to hold the
puck assembly 2 together in its assembled condition.
[0066] When assembling the puck assembly 2, one first inserts the driver element 7 into
the insulator 8. Then the insulator 8 with the driver element 7 is inserted into the
heat transferring element 9.
[0067] Next, the plurality of LEDs 11, optionally arranged on the base 12, is mounted on
the heat transferring element 9. This may be done by means of a suitable thermal interface
material, for example a thermal paste or glue. Thereby, the heat transferring element
9 is brought to be arranged in heat transferring relationship with the plurality of
LEDs 11.
[0068] Then, leads of the driver element 7 are soldered to the plurality of LEDs 11 and
the cover element 13 is mounted such as to cover the plurality of LEDs 11.
[0069] Next, the electrical connection element 6 is mounted onto the insulator 8, for example
by snapping, pinching or gluing it onto the insulator 8.
[0070] Then, an anode is soldered onto the electrical connection element 6 or, alternatively,
a clip is pressed into the electrical connection element 6, such as to enable electrical
connection between the electrical connection element 6 and a source of electrical
energy.
[0071] Finally, the shrink sleeve 14 is arranged over the puck assembly 2. More particularly,
the shrink sleeve 14 is arranged such as to extend over the heat transferring element
9 and overlap with the insulator 8 on the one side and, where present, the cover element
13 on the other side.
[0072] To complete the assembly of the lighting device 1 the puck assembly 2 is inserted
into the cavity 31 formed by the inner shell element 3 (cf. Fig. 5) where it is glued
to the surface of the inner shell element 3 facing the cavity 31 by means of suitable
thermal interface material or glue 15 (cf. Fig. 2). The now assembled lighting device
1 is heated to shrink the shrink sleeve 14. Thereby, the heat spreading element 9
is brought to be arranged in heat transferring relationship with the inner shell element
3 via the thermal interface material or glue 15.
[0073] The thus assembled puck assembly 2 and lighting device 1 is illustrated on Figs.
1 and 2.
[0074] Turning now again to Fig. 3, the flow or transfer of the heat generated by the plurality
of LEDs 11 through a lighting device according to the invention will now be explained.
[0075] The heat is generated by the plurality of LEDs 11. From the plurality of LEDs 11,
the heat flows as illustrated by the arrow 16 through the thermal interface material
by means of which the plurality of LEDs 11, optionally arranged on the base 12, is
mounted on the heat transferring element 9, to the heat transferring element 9. From
the heat transferring element 9 the heat flows as illustrated by the arrow 17 along
the heat transferring element 9 through the thermal interface material or glue 15
affixing the puck assembly 2 to the inner surface 32 of the inner shell element 3
through to the outer surface 33 of the inner shell element 3 and into the hermetically
sealed gas chamber 5 where the heat heats up the substantially one single gas. By
means of the thus heated substantially one single gas, the heat then flows as illustrated
by the arrows 18 through the hermetically sealed gas chamber 5 to the inner surface
41 of the outer shell element 4, which is colder than the inner shell element 3. Finally,
the heat flows through the outer shell element 4 and is as illustrated by the arrows
19 transferred from the outer surface 42 to the surroundings, thus cooling down the
substantially one single gas.
[0076] The thus cooled down substantially one single gas will subsequently flow back towards
the warmer inner shell element 3, thus completing the heat transfer cycle.
[0077] Turning now to Figs. 6 and 7, a perspective side view and a perspective exploded
view, respectively, of a lighting device 101 according to a third embodiment of the
invention is shown.
[0078] The lighting device 101 is very similar to that described above in relation to the
two first embodiments shown in Figs. 1 to 5, and thus only those features that differ
from from the above will be described in the following.
[0079] The lighting device 101 comprises a plurality of LEDs 11. The plurality of LEDs 11
and where present the base 12 are mounted in the puck assembly 2 such a way that the
plurality of LEDs 11 are oriented in a substantially vertical position, i.e. in a
position parallel with the longitudinal extension of the puck assembly 2.
[0080] The heat transferring element 9 is therefore arranged over the plurality of LEDs
11. To enable this arrangement the heat transferring element 9 is provided with a
plurality of openings 91 dimensioned and sized such as to each provide for a clearance
or gap between the respective LED of the plurality of LEDs 11 and the heat transferring
element 9. The clearance or gap provided by the respective openings 91 is arranged
adjacent to the solder points providing the electrical connection to the respective
LED of the plurality of LEDs 11 and thereby provide an electrical clearance.
[0081] In this embodiment the heat transferring element 9 may be a flexible element, for
example made of a graphite sheet or a suitable metal sheet. In case of a graphite
sheet, an example would be those produced by GrafTech, one such being their model
SS400 a graphite sheet having a thickness of 0.94 mm and a thermal conductivity of
400 W/mK.
[0082] Where a base 12 is provided for, the base 12 may likewise be a flexible base, such
as a flexible printed circuit board, for example of a PA, PI or FR4 type material.
[0083] Furthermore, with reference especially to Fig. 7, the puck assembly 2 comprises in
this embodiment a spring bush 20. The spring bush 20 is in the assembled condition
of the puck assembly 2 arranged extending inside of and abutting the heat transferring
element 9 or, where present, the base 12. The spring bush 20 further comprises a rim
201 adapted for alignment of the plurality of LEDs 11 and the heat transferring element
9. Thereby easy assembly of the puck assembly 2 as well as of the puck assembly 2
with the inner shell element 3 is provided for.
[0084] The spring bush 20 may be a simple plastic element, or alternatively a metal element,
adapted for applying a constant pressure to the plurality of LEDs 11 and, where present,
the base 12, such as to allow a good thermal contact with the inner shell element
3.
[0085] A lighting device 1, 100, 101 according to the invention may find application in
many diverse fields. Non-limiting examples are consumer lamps, such as candles, bulbs,
spot lights, TLED, professional lamps, especially street light lamps such as SON,
SOX, HPL, ML lamps, consumer luminaires, such as indoor luminaires, professional luminaires,
such as indoor spots, and outdoor luminaires, street lights, integrated lamp-luminaire
designs. Further applications being enabled as the lighting devices according to the
invention are watertight and can be easily coated with to prevent organic growth include
special lighting such as lighting in extreme environments, e.g. in pigsties with high
ammonia levels, and underwater lighting.
[0086] The person skilled in the art realizes that the present invention by no means is
limited to the preferred embodiments described above. On the contrary, many modifications
and variations are possible within the scope of the appended claims.
[0087] Additionally, variations to the disclosed embodiments can be understood and effected
by the skilled person in practicing the claimed invention, from a study of the drawings,
the disclosure, and the appended claims. In the claims, the word "comprising" does
not exclude other elements or steps, and the indefinite article "a" or "an" does not
exclude a plurality. The mere fact that certain measures are recited in mutually different
dependent claims does not indicate that a combination of these measured cannot be
used to advantage.
1. A lighting device (1, 100, 101) comprising:
a puck assembly (2) comprising a plurality of LEDs (11), and
a cover element comprising an outer shell element (4) adapted for forming a light
exit surface of the lighting device and an inner shell element (3),
the outer shell element and the inner shell element forming together a hermetically
sealed gas chamber (5), the hermetically sealed gas chamber being filled with substantially
one single gas adapted for functioning as a heat transferring medium for transferring
heat from the puck assembly towards the outer shell element, and
the inner shell element forming a cavity (31) adapted for accommodating the puck assembly
at least partially in such a way that the puck assembly is arranged outside the hermetically
sealed gas chamber in a heat transferring relationship with the inner shell element
and thereby with the substantially one single gas provided in the hermetically sealed
gas chamber.
2. A lighting device according to claim 1, wherein the outer shell element (4) and the
inner shell element (3) forming together the hermetically sealed gas chamber (5) are
made of a glass or a ceramic and are manufactured as a separate part in one piece
using a high temperature glass or ceramics processing method.
3. A lighting device according to any one of the above claims, wherein a transition (43)
between the outer shell element (4) and the inner shell element (4) is formed as a
continuous transition.
4. A lighting device according to any one of the above claims, wherein the outer shell
element (4) and the inner shell element (3) form together a hermetically sealed gas
chamber (5), the hermetically sealed gas chamber being filled with substantially one
single gas adapted for functioning as a heat transferring medium for transferring
heat from the puck assembly towards substantially all of the surface of the outer
shell element.
5. A lighting device according to any one of the above claims, wherein the inner shell
element (3) comprises a surface element (34) extending through at least a part of
the puck assembly in the assembled condition of the lighting device, the surface element
(34) forming a cavity (51) forming part of the hermetically sealed gas chamber (5).
6. A lighting device according to claim 5, wherein, in the assembled condition of the
lighting device, the surface element (34) of the inner shell element extends centrally
through at least a part of the puck assembly (2) in a substantially longitudinal direction
of the puck assembly.
7. A lighting device according to any one of the above claims, wherein the puck assembly
(2) comprises a heat spreading element (9) arranged in heat transferring relationship
with the plurality of LEDs and with the inner shell element in an assembled condition
of the lighting device.
8. A lighting device according to claim 7, wherein the puck assembly comprises a driver
element (7) adapted for driving the plurality of LEDS and a driver element insulator
(8), the driver element insulator being arranged such as to heat insulate the driver
element from the heat spreading element in an assembled condition of the puck assembly.
9. A lighting device according to any one of the above claims, and further comprising
a shrink sleeve (14) made of a Thermal Interface Material, TIM, and being adapted
for extending between at least a part of the puck assembly and the inner shell element
in an assembled condition of the lighting device.
10. A lighting device according to any one of the above claims, wherein the puck assembly
comprises any one or more of a cover element (13) arranged such as to extend over
the plurality of LEDs in an assembled condition of the puck assembly, and an electrical
connection element (6).
11. A lighting device according to any one of the above claims, wherein the puck assembly
comprises a spring bush (20) adapted for applying a constant pressure to the plurality
of LEDs, the spring bush (20) comprising a rim (201) adapted for alignment of the
plurality of LEDs and the heat transferring element in the assembled condition of
the puck assembly.
12. A lighting device according to any one of the above claims, wherein the puck assembly
(2) in an assembled condition of the lighting device is attached to the inner shell
element (3) by means of thermally conductive glue (15).
13. A lighting device according to any one of the above claims, wherein the plurality
of LEDs are arranged on a base (12), the base being arranged such that the plurality
of LEDs are arranged in a horizontal or vertical alignment.
14. A lighting device according to any one of the above claims, wherein the substantially
one single gas is helium.
15. A lamp, luminaire or system comprising a light emitting device according to any one
of the previous claims and being used in one or more of the following applications:
consumer lamps or luminaires, professional lamps or luminaires, street lighting, underwater
lighting and lighting in extreme environments.