Note: Descriptions are shown in the official language in which they were submitted.
CA 02582044 2007-03-26
Title
Light Source with Heat Transfer Arrangement
Background of the Present Invention
Field of Invention
The present invention relates to a light source arrangement, and more
particularly to a light source with a heat transfer arrangement which
comprises a cooling
agent contained in an air-sealed chamber for substantially dissipating the
heat from the
light source through the phase equilibrium process of the cooling agent.
Description of Related Arts
Nowadays, the most common light sources for illumination are filament lamp
bulb and LED lighting. Due to the remarkable features of low power consumption
and
instant light emission, LED lighting is specially adapted to be utilized in
many electrical
appliances, such as the power on-off signal light and instructional signal
light of electric
equipment, indicating light of electronic clock, and etc.
Due to the technology of LED, the LED, nowadays, not only has excellent
properties of low power consumption and instant light emission but also
provides a
relatively high light intensity and lighting emission angle of the LED such
that the LED
becomes one of the common lighting apparatus applied in some specific area
such as
traffic light, signboard light, vehicle brake light and signal light, and
airport guiding
lighting.
However, when a plurality of light sources consumes electricity at the same
time, the heat generated from the light sources may cause a short circuit. In
other words,
the problem of overheat is one of the common drawbacks of the conventional
light
sources. In the applicant's another invention, in order to prevent the problem
of
overheating, the light source usually employs a heat sink directly contacting
with the light
source to dissipate the heat therefrom by means of conduction. Accordingly,
the heat
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sink is generally made of thermal conducting material, such as copper or
aluminum, such
that the heat generated from the light source will transfer to the heat sink
and dissipate to
the surroundings.
However, the heat sink and the light source is in an integral solid
connection,
the heat from the light source transferred from the light source to the heat
sink is still in
limited speed. When the temperature of the luminary element reaches 100 C, the
illumination and life span thereof will decrease accordingly. The luminary
element will
even be bumt out when its temperature rises to about 120 C.
Furthermore, when a large number of the light sources are utilized to form a
huge signboard, the overall weight of the signboard will be highly increased
by the heat
sinks of the light sources. In other words, the supporting frame must be rigid
enough to
support the heavy signboard having hundreds of heat sinks built-in with the
light sources.
Summary of the Present Invention
A main object of the present invention is to provide a light source with a
heat
transfer arrangement which comprises a cooling agent contained in a sealed
chamber for
substantially dissipating the heat from the light source through the phase
equilibrium
process of the cooling agent.
Another object of the present invention is to provide a light source with a
heat
transfer arrangement, wherein the cooling agent has a high heat conductivity
to quickly
and effectively transfer the heat away from the light source to the heat sink.
Another object of the present invention is to provide a light source with a
heat
transfer arrangement, wherein the heat transfer of the light source is a
process of
evaporation and condensation of the cooling a gent. In other words, the heat
from the
light source vaporizes the cooling agent within the sealed chamber while the
cooling
agent is condensed by a heat sink. Therefore, during the phase equilibrium
process of the
cooling agent, the heat can be more efficiently transferred from the light
source to the
heat sink.
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Another object of the present invention is to provide a light source with a
heat
transfer arrangement, wherein the heat sink can be located apart from the
light source so
that the weight of the light source can be substantially reduced so as to
enhance the
practical use of the light source.
Accordingly, in order to accomplish the above objects, the present invention
provides a light source, comprising: a light head, comprising:
a tubular supporting frame having an interior sp ace and a peripheral surface;
and
a luminary unit comprising a circuit for electrically connecting a power
source
and at least a luminary element electrically connected to the circuit for
emitting light; and
a heat transfer arrangement for dissipating heat generated from the light
head,
comprising:
a heat sink;
a heat conductor having a sealed chamber which has a first portion positioned
in
the interior space of the supporting frame and a second portion extended to
the heat sink;
and
a cooling agent contained in the sealed chamber of the heat conductor, wherein
the cooling agent is capable of being vaporized by the heat generated from the
luminary
unit and condensed by the heat sink so as to substantially enable the heat to
flow from the
luminary unit towards the heat sink.
These and other objectives, features, and advantages of the present invention
will become apparent from the following detailed description, the accompanying
drawings, and the appended claims.
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Brief Description of the Drawings
FIG. 1 is an exploded perspective view of a light source with a heat transfer
arrangement
according to a first preferred embodiment of the present invention.
FIG. 2A is a sectional view of the light source with the heat transfer
arrangement
according to the above first preferred embodiment of the present invention.
FIG. 2B is a sectional view of the heat conductor of the light source with the
heat transfer
arrangement according to the above first preferred embodiment of the present
invention.
FIG. 3 illustrates an alternative mode of the heat conductor of the heat
transfer
arrangement according to the above first preferred embodiment of the present
invention.
FIG. 4 is a sectional view of a light source with a heat transfer arrangement
according to
a second preferred embodiment of the present invention.
FIG. 5 illustrates an application of the light source with the heat transfer
arrangement
according to the above second preferred embodiment of the present invention.
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Detailed Description of the Preferred Embodiment
Referring to FIG. 1 of the drawings, a light source according to a first
preferred
embodiment of the present invention is illustrated, wherein the light source
comprises a
light head 10 and a heat transfer arrangement 20 for dissipating heat
generated from the
light head 10.
The light head 10 comprises a tubular supporting frame 11 having an interior
space 111 and a peripheral surface 112, and a luminary unit 12 comprising a
circuit 121
provided on the peripheral surface 112 of the supporting frame 11 for
electrically
connecting a power source P, and at least a luminary element 122 electrically
connected
to the circuit 121 for emitting light.
The heat transfer arrangement 20 comprises a heat sink 21, a heat conductor 22
having a sealed chamber 221, and a cooling agent 23 contained in the sealed
chamber
221. The sealed chamber has a first portion 222 positioned in the interior
space 111 of
the supporting frame 11 and a second portion 223 extended to the heat sink 21.
According to the first preferred embodiment of the present invention, the
first portion 222
is an end portion of the heat conductor 22 and the second portion 223 is an
opposite end
portion of the heat conductor 22. Accordingly, the cooling agent 23 is capable
of being
vaporized by the heat generated from the luminary unit 12 and condensed by the
heat
sink 21 so as to substantially transfer the heat flowing from the luminary
unit 12 towards
the heat sink 21.
According to the preferred embodiment, the supporting frame 11 is constructed
as an elongated hollow member to define the interior space 111 wherein the
supporting
frame 11 is made of material having high thermal conductivity such as copper
or
aluminum. Accordingly, the supporting frame 11 can be formed to have a
circular cross
section, triangular cross section, rectangular cross section, or polygonal
cross section,
wherein the first portion 222 of the heat conductor 22 is fittedly inserted
into the
supporting frame 11 in such a manner that the first portion 222 of the heat
conductor 22
must be in contact with a peripheral wall 110 having the peripheral surface
112 of the
supporting frame 11.
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As shown in FIG. 2A, the luminary element 122 is mounted on the peripheral
surface 112 of the supporting frame 11 to electrically connect with the
circuit 121.
According to the preferred embodiment, the luminary element 122 is a double
bonded
diode has two terminal electrodes electrically connected to the circuit 121 in
such a
manner that the light is emitted by the luminary element 122 when the two
terminal
electrodes are electrified. Practically, different kinds of luminary elements
122 can
provide different colors of light such as red, blue or green. It is worth to
mention that the
luminary element 122 can be the single bonded diode having a terminal
electrode
electrically connected to the supporting frame 11 while another terminal
electrode
electrically connected to the circuit 121.
As shown in FIG. 2A, the circuit 121 comprises an elastic board layer 1211
firmly attached to the peripheral surface 112 of the supporting frame 11, e.g.
by glue, and
a circuit arrangement 1212 formed on the board layer 1211 to electrically
connect to the
luminary element 122.
According to the advance technology at the time of the present invention, the
circuit 121 is preferred to be directly imprinted on the peripheral surface
112 of the
supporting frame 11 so that the luminary element 122 is mounted on the
peripheral
surface 112 of the supporting frame 11 to electrically connect with the
circuit 121.
For protecting the luminary element 122, the light head 10 further comprises a
transparent light shelter 13 sealedly mounted on the peripheral surface 112 of
the
supporting frame 11 to sealedly protect the circuit 121 and the luminary
element 122.
The light shelter 13 is preferably made of resin or other similar material
having high
thermo-resistance ability that is molded to integrally enclose the peripheral
surface 112 of
the supporting frame 11.
The light shelter 13 has a light projecting portion provide on the supporting
frame 11 at a position aligning with the luminary element 122 to function as a
lens 131 in
such a manner that the light produced by the luminary element 122 is arranged
to pass
through the light projecting portion of the light shelter 13 to outside. In
other words, the
light projecting portion of the light shelter 13 having a spherical shaped is
adapted to
amplify the light from the luminary element 122 so as to enhance the light
intensity of the
light head 10. Preferably, the luminary element 122 is positioned close to a
focus point
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of the light projecting portion of the light shelter to evenly distribute the
light
therethrough.
The heat sink 21, which is made of material having high thermal conductivity,
has a conductor socket 211 for the second portion 223 of the heat conductor 22
to
slidably insert thereinto. The heat sink 21, which has a plurality of heat
dissipating
blades 212, is arranged to cool down the cooling agent 23, which is evaporated
in vapor
form by the heat generated by the light head 10, in the first portion of the
heat conductor
22, so as to condense the cooling agent 23 within the sealed chamber 221 from
its vapor
form to its liquid form.
As shown in FIG. 2A, the heat conductor 22, which is made of high thermal
conductivity, is an elongated tubular member having two closed ends and
concealing the
sealed chamber 221 therein. The first portion 222 of the heat conductor 22
having a
corresponding cross sectional is fittedly inserted into the supporting frame
11 to
substantially increase a contacting surface area between the light head 10 and
the heat
conductor 22 for further enhancing the heat transfer from the light head 10 to
the heat
sink 21. Accordingly, the first portion 222 of the heat conductor 22
preferably has a non-
circular cross sectional to prevent an unwanted rotational movement of the
light head 10
with respect to the heat conductor 22 when the first portion 222 of the heat
conductor 22
is engaged with the light head 10.
The cooling agent 23 should be a liquid having lower vaporization temperature,
e.g. 60 C-70 C, wherein the cooling agent 23 is concealed within the sealed
chamber 221
of the heat conductor 22. When the light head 10 is utilized over a period of
time, the
luminary element 122 produces heat and the temperature within the sealed
chamber 221
is increased.
When the temperature of second portion 23 of the sealed chamber 221 of the
heat conductor 22 that is received in the light head 10 reaches or is higher
than the
vaporization temperature of the cooling agent 23, the cooling agent 23 starts
to be
vaporized at the second portion 23. According to the theory of heat transfer,
heat flows
from a higher temperature region to a lower temperature region. Therefore, the
cooling
agent 23 in vapor form flows to the first portion 22 of sealed chamber 221 of
the heat
conductor 22 that is extended to the heat sink 23 and a temperature lower than
the
temperature of the light head 10. Then, the cooling agent 23 is cooled down by
the heat
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sink 21 to condense back to its liquid form. Accordingly, the heat from the
light head 10
is more efficiently transferred to the heat sink 21 through the phase
equilibrium process
of the cooling agent 23. In addition, the cooling agent 23 will not vanish
during the
vaporization process thereof because the cooling agent 23 is sealedly
contained within the
sealed chamber 221 of the heat conductor 22, so as to prolong the service life
span
thereof.
It is worth to mention that the cooling agent 23 has higher heat sensitivity
than
metal so that it can quickly and effectively transfer the heat from the light
head 10 to
dissipate from the heat sink 21 such that the surface of the light shelter 13
can be
maintained at a temperature that the operator is able to touch without burning
his or her
hand even though the light head 10 is utilized for a long period of time.
As shown in FIG. 2B, the heat conductor 22 further has a plurality of
conduction channels 224 spacedly and longitudinally provided on a surrounding
wall of
the sealed chamber 221, i.e. an inner surface of the heat conductor 22,
wherein the
conduction channels 224 are extended from the first portion 222 of the heat
conductor 22
to the second portion 223 thereof to guide the cooling agent 23 flowing
between the heat
sink 21 and the light head 10. According to the preferred embodiment, the
conduction
channels 224 can be capillary grooves of any cross section, such as semi-
circular,
triangular, or rectangular, parallelly and longitudinally indented along the
inner surface of
the heat conductor 22.
Accordingly, the cooling cycle of the cooling agent is that the cooling agent
23
will be vaporized by the heat of the light head 10 and cooled down by the heat
sink 21 to
condense the cooling agent 23 back to its liquid form. The cooling agent 23 is
guided to
flow back towards the light head 10 along the conduction channels 224 to
enhance the
cooling cycle. In other words, when the vaporized cooling agent 23 is cooled
down in the
second portion 223 to liquid form through the heat sink 21, the conduction
channels 224
are arranged to guide the cooling agent 23 back to its original position. In
addition, the
conduction channels 224 also substantially increase the contacting area
between the heat
conductor 22 and the cooling agent 23 so as to enhance the cooling effect of
the light
source of the present invention.
As shown in FIG. 2A, the heat sink 21 is embodied to be positioned on top of
the supporting frame 11 such that a top portion of the heat conductor 22
embodies as the
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second portion 223 thereof to mount with the heat sink 21 while a bottom
portion of the
heat conductor 22 embodies as the first portion 222 thereof to mount with the
supporting
frame 11. Therefore, when the heat vaporizes the cooling agent 23 to flow
upward, the
cooling agent 23 is then condensed by the heat sink 21 to drop down to the
bottom
portion of the sealed chamber 221 to re-contact with the light head 10.
Therefore, the heat
sink 21 is preferred to mount on the supporting frame 11 to enhance the phase
equilibrium process of the cooling agent 23.
According to the preferred embodiment, ether (C2H5)20 or ethanol can be used
as the cooling agent 23 which is in liquid form ether at room temperature and
has a
vaporization temperature about 60 C or less. The amount of cooling agent 23 to
be used
is preferred to be about 30% of the volume of the sealed chamber 221. For
example,
when an interior diameter of the sealed chamber 221 of the heat conductor 22
is designed
to be 3-4 mm to form a total volume of about 3-6 ml for the sealed chamber 221
and 1-2
ml of cooling agent 23 is received in the sealed chamber 221, such heat
transfer
arrangement 20 can support the heat dissipation of the light head 10 designed
to have a
power of 18 W, such as 3V and 6 A, to either produce red light with 200 lumen
or more,
i.e. about the illumination of a 55 W Halogen lamp through a red light filter,
or blue light
with 80 or more lumen. However, a 55 W Halogen lamp can merely produce a 30
lumen
blue light through a blue light filter.
According to the preferred embodiment, the light source of the present
invention is embodied to function as a light bulb for detachably mounting on a
light bulb
socket so as to electrically connect to the power source. The light head 10
thus comprises
an electric adapter 14 formed at the supporting frame 11 to electrically
connect to the
luminary unit 12 wherein the electrical adapter 14 is a plug for plugging into
the light
bulb socket and is constructed as a universal adapter for electrically
connecting with the
power source P via the light bulb socket.
As shown in FIG. 2A, the light source of the present invention is embodied to
vertically mount on the light bulb socket that, generally, the liquid form
cooling agent 23
is contained at the bottom portion of the sealed chamber 221 of the heat
conductor 22 to
communicate with luminary unit 12 on the supporting frame 11. It is worth to
mention
that the light source can be mounted to the light bulb socket at a horizontal
position since
the liquid form cooling agent 23 would sink at the lower portion of the sealed
chamber
221. In other words, the phase equilibrium process of the cooling agent 23 can
occur due
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to the heat of the light head 10 in accordance with any oriental position of
the supporting
frame 11 with respect to the heat sink 21.
FIG. 3 illustrates an alternative mode of the heat conductor 22' which is
constructed by the supporting frame 11' wherein the supporting frame 11' is
formed as an
elongated tubular member to form the interior space 111' as the sealed chamber
221' so
as to contain the cooling agent 23' within the interior space 111' of the
supporting frame
11'. In other words, an upper portion of the supporting frame 11' functions as
the second
portion 223' of the heat conductor 22' to mount with the heat sink 21' while a
lower
portion of the supporting frame 11' function as the first portion 222' of the
heat
conductor 22', wherein the luminary unit 12' is provided at the bottom portion
of the
supporting frame 11' to communicate with the cooling agent 23' through the
heat
transfer.
As shown in FIG. 4, a light source of a second embodiment is illustrated which
is another alternative mode of the first preferred embodiment of the present
invention,
wherein the light source has the same structural components of the first
embodiment
thereof. The heat conductor 22" is an elongated tubular member having the
first portion
222" extended from the light head 10 and the second portion 223" mounted to
the heat
sink 21", wherein the heat sink 21" is positioned apart from the light head
10. It is worth
to mention that the light head 10 is capable of communicating with the heat
sink 21"
through the heat conductor 22" so as to transfer the heat from the light head
10 to the heat
sink 21" through the phase equilibrium process of the cooling agent 23".
Due to the high heat sensitivity of the cooling agent 23", the cooling agent
23"
is vaporized by the heat from the light head 10" in the first portion 222" of
the heat
conductor 22" and is condensed by the heat sink 21" at the second portion 223"
of the
heat conductor 22". In other words, even the light head 10 is positioned apart
from the
heat sink 21 ", the heat from the light head 10 can be quickly and effectively
transferred to
the heat sink 21" through the heat conductor 22", as shown in FIG. 4.
The light source of the second embodiment is specially designed for
commercial use such as using in a billboard. As shown in FIG. 5, a plurality
of light
heads 10 are supported on a signboard to electrically connect with the power
source
wherein the heat conductor 22" is extended from each of the light heads 10 to
mount to
the heat sink 21" in such a manner that the heat from the light heads 10 can
be
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substantially transferred to the heat sink 21" through the heat conductor 22".
Therefore,
the heat from the light heads 10 can be effectively dissipated by using one
single big heat
sink 21" installed in an appropriate area. It is appreciated that the heat
sink 21" would be
constructed to be a powerful heat sink for commercial use such as fluid
cooling system so
as to cool down the cooling agents 23" within the heat conductors 22" to
dissipate the
heat transferred from the light heads 10.
One skilled in the art will understand that the embodiment of the present
invention as shown in the drawings and described above is exemplary only and
not
intended to be limiting.
It will thus be seen that the objects of the present invention have been fully
and
effectively accomplished. It embodiments have been shown and described for the
purposes of illustrating the functional and structural principles of the
present invention
and is subject to change without departure form such principles. Therefore,
this invention
includes all modifications encompassed within the spirit and scope of the
following
claims.
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