Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: LED LIGHT BULB
FIELD OF THE INVENTION
The present invention relates to an LED light bulb
used to replace existing lighting, especially residential
incandescent light bulbs.
BACKGROUND OF THE INVENTION
The most common lighting sources used in
residential lighting are incandescent light bulbs that
produce light using a wire filament which is heated up by
the electrical current running through the filament
contained within a vacuum which may also contain a
mercury vapor or halogen atmosphere. Many problems exist
with these light bulbs in that such bulbs fail
frequently, produce large amounts of heat and use
significant amounts of electricity to produce light.
These disadvantages result in high maintenance costs,
rises in room temperature and unnecessary energy
consumption.
There have been attempts to improve the efficiency
of such light bulbs such as, for example, the use of
lower power fluorescent light bulbs which can be utilized
in a standard incandescent light bulb screw base fixture.
While such bulbs do use less power, the problem of the
mercury vapor atmosphere within the bulb is still present
which can create environmental problems on disposal.
There have also been attempts to replace
incandescent light bulbs with LED light bulbs such as
shown-for example in US Patent 6,609,804. However, such
LED light bulbs do not easily replace incandescent light
sources nor are they significantly more energy efficient
for the same light output.
There still remains a need for a light source for
residential lighting which can easily replace standard
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incandescent light bulbs, but use less power, run cooler
and have a longer life span.
SUMMARY OF THE INVENTION
The present invention is directed to an LED light
bulb comprising an interface connecting the bulb to a
standard light fixture, a power control section for
supplying and controlling power to an LED array, an
electro thermal core for interconnection of a high
density array of LEDs providing electrical
interconnection and thermal collection for dispersion of
the heat and an LED array producing a white light of a
suitable intensity and color.
The present invention is also directed to a novel
LED array using an electro thermal core for
interconnection of a high density array of LEDs providing
electrical interconnection and thermal collection for
dispersion of the heat and an LED array producing a white
light of a suitable intensity and color.
The present invention is also directed to a novel
a power control section for supplying and controlling
power to an LED array comprising a non-switching linear
design based on a monolithic approach of power control,
whereby, the load (the LED array) becomes part of the
power control system.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown
in the drawings,_wherein:
Figure 1 is a perspective view of an embodiment of
an LED light bulb according to the present invention;
Figure 2 is a perspective view of the bottom of
the light bulb of Figure 1;
Figure 3 is a side elevation view in cross-section
of the LED bulb of Figure 1;
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Figure 4 is an exploded perspective view of the
electro thermal core of the LED bulb of Figure 1;
Figure 5 is a top plan view of the electro thermal
core of the LED bulb of Figure 1;
Figure 6 is a circuit diagram of the LED bulb of
Figure 1;
Figure 7 is a perspective view of an embodiment of
the LED light bulb in a ceiling panel fixture; and
Figure 8 is a side elevation view partly in cross
section of an embodiment of an LED light bulb of the
present invention in a street lamp fixture.
DETAILED DESCRIPTION OF THF~ PREFERRED EMBODIMENTS
The LED light bulb of the present invention is
comprised of four major blocks - an interface, a
power/control section, an electro-thermal core and an LED
Array/Optics. The interface connects the LED light bulb
to an electrical power source. Preferably, the interface
allows the LED light bulb to be used in existing fixtures
as described below. The power/control section is
responsible for supplying and controlling power to the
LED bulb array and ensures optimum light output under a
wide range of ambient temperatures, as well as maximizing
the life of the individual LEDs. The electro/thermal
core section makes possible the interconnection of a very
high density array of LEDs. The LED array/optics
provides the desired luminous spectrum and distribution
of the light from the LEDs. The structure and operation
of the LED light bulb of the present invention will now
be described with respect to various preferred
embodiments. _
A first embodiment of the LED light bulb of the
present invention for use as a replacement for
residential incadescent light bulbs is illustrated in
figures 1 to 5 generally indicated by the numeral 10.
The LED light bulb 10 is provided with a screw base
interface 12 which fits into the standard screw base
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fixtures. The screw base 12 is affixed to a thermal cap
14 containing openings 16 to allow for air flow through
the bulb 10 as will be described later.
The screw base 12 also houses the power/control
electronics used for powering the LED bulb array. The screw
base 12 is a flanged form with a cavity space 18 that
accommodates the power/control circuitry 20. An acrylic
frosted diffused lens 22 covers the LED bulb array 24 and is
attached to the thermal cap 14.
The electro/thermal core section 24 makes possible
the interconnection of a very high density array of LEDs 26.
The core 24 provides electrical interconnection, thermal
collection and physical support for the LEDs 26. The heat
generated in the array is dispersed by a controlled
convection air flow through the thermal cap 14.
As illustrated in Figures 3 to 5, the Electro-Thermal
Core 24 is a segmented structure which consists of a series
of disks stacked so as to form a core. There are 3 disk
types: circuit disks 28, metal disks 30, and insulator disks
32. All disks types are designed to have a high thermal
conductance. The disks are secured by means of a retaining
rod 34 that is threaded through the center of the disk stack.
The surfaces of the disks are machined and mated so
as to reduce thermal resistances between them for maximum
heat transfer.
The circuit disks 28 have twelve 30 degree segments
36; one segment 38 is split and serves as the circuit
interconnection point. This allows each circuit disk 28 to
have twelve LED bulbs 26 connected in series. Four circuit
disks 28 are connected in series to provide an LED cluster of
48 LED bulbs. To increase light output, a number of LED
clusters are connected in parallel. Typically 2 to 6 such
clusters are connected in parallel. To improve light
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diffusion, the LED clusters are interleaved and not stacked
one above the other. Metal disks 30 and insulating disks 32
are placed appropriately in the stack and thermal compound is
used on all mating surfaces. The stack is threaded together
by a insulated retaining rod 34 and attached to the thermal
cap 14. The cap 14 serves several functions and is one of
the key design elements.
The constructed core is then thermally and
mechanically secured to the thermal cap thereby completing
the thermal circuit.
The luminous spectrum and distribution of the light
from the LED array is a product of the LED type and Optic
Path. Preferably two types of 5mm LEDs are utilized to
produce a white light with a CRI of 85+.
The core is covered and contained by a frosted
diffuser which has two primary functions of light
distribution and air flow control. The light from the
individual LEDs is collated and scattered using a frosted
diffuser lenses thereby evenly distributing the light in all
directions. The cavity of the frosted diffuser lenses, when
attached to the thermal cap, creates a venturi. Cool air
enters the inlet and passes over an impeller which creates a
consistent uniform turbulence which in turn, increases the
rate of air flow through the venturi, thereby reducing the
core temperature. Hot air is then ported through the venturi
outlet completing the air flow path.
The power_/control section 20 is responsible for
supplying and controlling power to the LED bulb array 24 and
ensures optimum light output under a wide range of ambient
temperatures, as well as maximizing the life of the LEDs 26.
As illustrated in Figure 6, the power/control section 20
provides rectification and filtering through a Linear DC
supply having Linear Current Regulation and Optical Choke.
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The power/control section 20 utilizes a unique technology
called an "optical ballast".
Conventional LED power controllers are based on
various switching circuits that are placed in series with the
LED bulb array. The switching rate and duration controls the
effective power, and therefore, the heat generated. Some
drawbacks to these prior arrangements include RFI/EMI- line
contamination causing interference with other electronic
devices, circuit complexity with high part count, additional
heat generated by controller circuit which reduces efficiency
and circuit life, and strobe effects.
The Optical Ballast Technology eliminates the above
drawbacks by utilizing a non-switching linear design based on
a monolithic approach of power control, whereby, the load
(the array) becomes part of the power control system.
The external portion of the controller is a Very Low Voltage
(VLV) design and consumes only 2$ of the total energy
required by the array. The rest of the power required for
the array is trapped in the array and the LEDs are forced to
work with a fixed range of power. Since the power range is
fixed, the LEDs dynamic resistance becomes the power
controller, and not the external controller. Thus the power
required for the array includes the power required to control
the array and all the power is used to produce light. By
controlling the the array in this way the array is almost
100$ efficient since all the power is producing light and any
heat produced is the result of producing light, and not
generated in the controlling circuit. The result is that the
power required to control the array is a portion of the total
light_output, hence the name "Optic Ballast".
It has been found that a prototype repalcement for an
incadescent bulb as illustratede in Figures 1 to 6 containing
4 LED clusters or 192 LEDs produces the equivalent light as a
60 watt incandescent bulb while consuming about 20 watts or
1/3 the power of an 60 Watt incandescent bulb resulting in
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about 66~ Power Savings. The operating temperature of the
bulb was 125 deg. F., 35 deg. lower than a 60 watt bulb. The
expected life expectancy of the LED bulb is 20+ Years in
continuous use.
In the first preferred embodiment, as described
above, the LED light bulb 10 is designed to replace an
existing 120 volt incandescent light bulb and. By changing
the interface, the bulb may be used in other types of
fixtures as well as for other applications.
For example, the LED light bulb of the present
invention as described above, may also be used to replace
other types of light sources, such as fluorescent lights. An
in lay panel, similar to existing fluorescent fixtures may
be provided with a number of receptacles for a screw base.
Generally anywhere from 4 to 8 such receptacles are provided
depending upon the desired light output. The receptacles are
wired to a junction box for connection to the electrical
wires from the supply.
Alternatively, as illustrated in Figure 7, a
replacement lay in panel 50 may be provided to replace
exisitng fluorescent lay in panels. The panel 50 is provided
with a recess 52 containing the LED light bulbs 54. The
interface is a junction box 56 which allows direct connection
to the wiring in a onventional manner. The power/control
circuity may be contained within the junction box 56 and the
output wires 58 of the power/control section lead to
connectors for the LED arrays. A frosted diffuser panel 60
is provided to collate and scatter the light from the LED
arrays- thereby evenly distributing the light in all
directions.
A further embodiment of an LED light bulb 68 of the
present invention is illustrated in Figure 8 for use as a
street light in a typical cobra head street light head 70.
The light bulb 68 is provided with a screw base interface 72
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which allows it to be connected to the light head 70.
Similar to the first embodiment, the power/control section 74
is contained within the screw base 72. The electro/thermal
core and LED array are mounted in the top of the cobra head
and connected to the power/control section 74 in the screw
base 72 by wires 75. The electro/thermal core 76 contains
the high density of LEDs 78 arranged similar to the first
embodiment. The LEDs 78 are arranged in 8 clusters of 48
LEDs in each cluster. The core is constructed similar to the
first embodiment with circuit disks, metal disks and
insulator disks. As the cobra head 70 is provided with a
diffuser cover 80, a separate difusser for the LED light bulb
68 is not required.
Although various preferred embodiments of the present
invention have been described in detail, it will be
appreciated by those skilled in the art that variations may
be made thereto without departing from the spirit of the
invention.
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