U.S. patent application number 12/887307 was filed with the patent office on 2011-03-24 for light emitting diode light bulbs with strands of leds.
Invention is credited to Kuo-Chiu CHIANG, Kai Kong NG.
Application Number | 20110069487 12/887307 |
Document ID | / |
Family ID | 39459903 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110069487 |
Kind Code |
A1 |
NG; Kai Kong ; et
al. |
March 24, 2011 |
Light Emitting Diode Light Bulbs with Strands of LEDs
Abstract
The present invention relates to an LED light bulb. The LED
light bulb comprises a base and a hollow shell. The base has a
closed end, an open end and a sleeve between the two ends. The
shell is connected to the open end of the base. The LED light bulb
comprises at least two LEDs substantially linearly arranged within
the shell. By arrangement of multiple LEDs one or more strands the
luminance or brightness of the bulb is improved compared with a
bulb with one LED or with several horizontally arranged LEDs in a
common place, without sacrificing the advantage of energy
saving.
Inventors: |
NG; Kai Kong; (Hong Kong,
HK) ; CHIANG; Kuo-Chiu; (Dongguan City, CN) |
Family ID: |
39459903 |
Appl. No.: |
12/887307 |
Filed: |
September 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12078549 |
Apr 1, 2008 |
7883242 |
|
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12887307 |
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Current U.S.
Class: |
362/249.02 |
Current CPC
Class: |
F21W 2121/00 20130101;
F21Y 2107/00 20160801; F21V 3/00 20130101; Y02B 20/342 20130101;
Y02B 20/30 20130101; H05B 45/37 20200101; H05B 45/00 20200101; F21V
3/02 20130101; F21Y 2105/00 20130101; Y02B 20/383 20130101; F21K
9/23 20160801; F21Y 2103/10 20160801; F21Y 2115/10 20160801; F21V
19/0005 20130101 |
Class at
Publication: |
362/249.02 |
International
Class: |
F21S 4/00 20060101
F21S004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 23, 2007 |
TW |
0096206431 |
Claims
1. A bulb, comprising: a base, the base including a closed end, an
open end and a sleeve therebetween, wherein the sleeve serves as an
electrode and the closed end has a contact point serving as another
electrode; a hollow shell connected to the open end of the base;
and a strand of at least two LEDs, each LED including a base having
electrical terminals and an envelope extending from the base to an
envelope top end distal from the base, the LEDs joined together and
arranged within the shell such that for all LEDs, but for the last
LED, in each strand, the envelope top end of any given LED in the
strand substantially faces the base of an adjacent LED in the
strand, wherein the bulb is adapted for connection to a power
source.
2-4. (canceled)
5. The bulb according to claim 1, wherein the base of the bulb is
hollow, and, within the hollow base, the bulb further comprises a
power converter for converting AC power to DC power to be supplied
to the LEDs.
6. The bulb of claim 5, wherein both the two electrodes are
connected to the input of the power converter; and the bulb further
comprises an insulating part separating and insulating the two
electrodes.
7. The bulb according to claim 6, wherein the power converter
includes a filter circuit, a bridge rectifier circuit, and a
resistor; the bridge rectifier circuit is connected to the
electrodes via the filter circuit, and the output of the bridge
rectifier circuit is connected to LEDs via the resistor.
8. The bulb according to claim 7, wherein the sleeve of the base
has external threading.
9. The bulb according to claim 1, wherein the shell is made of
translucent or transparent plastic.
10. The bulb according to claim 1, wherein the shell is made of
translucent or transparent glass.
11. The bulb according to claim 1, wherein the LEDs are connected
in parallel.
12. The bulb according to claim 1, wherein the LEDs are connected
in series.
13. An LED bulb, the bulb comprising: a base, the base including a
closed end, an open end and a sleeve therebetween, wherein the
sleeve serves as an electrode and the closed end has a contact
point serving as another electrode; a hollow shell connected to the
open end of the base; and at least two strands of LEDs wherein each
strand of LEDs includes at least two LEDs, each LED having a base
comprising electrical terminals and an envelope extending from the
base to an envelope top end distal from the base, the LEDs joined
together and arranged within the shell such that for all LEDs, but
for the last LED, in each strand, the envelope top end of any given
LED in the strand substantially faces the base of an adjacent LED
in the strand, wherein the bulb is adapted for connection to a
power source.
14-16. (canceled)
17. The bulb according to claim 13 wherein the LEDs are connected
in parallel within each strand.
18. The bulb according to claim 13 wherein the LEDs are connected
in series within each strand.
Description
CROSSREFERENCE
[0001] This application is a continuation of U.S. application Ser.
No. 12/078,549, file Apr. 1, 2008, and entitled "Light Emitting
Diode (LED) Light Bulb," which is based on Republic of China
(Taiwan) Application No. 0096206431 filed Apr. 23, 2007, the
entirety of these applications is hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a light bulb. In
particular, the present invention relates to a light emitting diode
(LED) light bulb that comprises one or more light emitting diodes
(LEDs) in one or more substantially linear arrangements.
BACKGROUND OF THE INVENTION
[0003] Most existing light bulbs are incandescent light bulbs or
fluorescent light bulbs. An incandescent light bulb typically
comprises a base, a glass shell, a thin filament which is normally
a thin tungsten filament within the shell, and an inert gas within
the shell. When an electric current passes through the tungsten
filament and heats it up to an extremely high temperature
(2000.degree. C. to 3000.degree. C. depending on the filament type,
shape, size, and amount of current passed through), heat radiation
occurs and visible light is produced. However, the incandescing
process is considered highly inefficient, as over 98% of its energy
is emitted as invisible infrared light (or heat) and the luminance
cannot further improve. In addition, the typical lifespan of an
incandescent bulb is limited to about 1,000 hours.
[0004] By comparison, a fluorescent light bulb is filled with gas
containing low-pressure mercury vapor and an inert gas such as
argon or xenon. The inner surface of the bulb is coated with a
fluorescent (and often slightly phosphorescent) coating made of
various blends of metallic and rare-earth phosphor salts. When
electricity passes through mercury vapour, the mercury vapour
produces ultraviolet light. The ultraviolet light is then absorbed
by the phosphorus coating inside the bulb, causing it to glow, or
to fluoresce. While the heat generated by fluorescent light is much
less than its incandescent counterpart, efficiencies are still lost
in generating the ultraviolet light and converting this light into
visible light. In addition, mercury is considered detrimental to
the health of people and animals. Therefore, if the fluorescent
bulb breaks, exposure to the substance can be hazardous.
Fluorescent bulbs are typically more expensive than incandescent
bulbs, but they have life spans of about 10,000 hours.
[0005] A light emitting diode light bulb is another type of light
bulb. The LED bulb typically has high durability with no need to
worry about the filament breaking as occurs with respect to
incandescent bulbs or the noted hazards as can occur with respect
to fluorescent bulbs. LED light bulbs have a long life span of
approximately 50,000 to 100,000 hours. The LED bulb generates
little heat and has little parasitic energy loss, thereby reducing
the overall electricity used. This, in turn, increases the
possibilities of reducing electricity bills. Since the LED light
bulb has so many advantages over the incandescent bulb and the
fluorescent bulb, it is considered to be a cost-effective yet high
quality replacement for incandescent and fluorescent light
bulbs.
[0006] There are already some LED bulbs in the market. These LED
bulbs either contain one LED in the bulb or at least two LEDs
horizontally fixed directly on one printed circuit board (PCB) in
the bulb. For the bulb containing only one LED, the light is
generally not bright enough. The luminance is hard to improve for a
single bulb containing a single LED. For bulbs having at least two
LEDs horizontally fixed on one PCB, the LEDs are in the same
horizontal level and the distances that can be brightened by those
LEDs are similar because of their attachment to the PCB. When the
bulb shell increases in size, the LEDs will all have a longer
distance to the bulb shell. As the distance from the LED to the
shell increases, the brightness becomes weaker and dimmer. Light is
governed by an increase-square law of physics namely that the
intensity/strength of the light from a source is inversely
proportional to the square of the distance from the source.
Therefore, the use of LED bulbs in the prior art is limited to
applications which do not have a high luminance requirement. In
order to broaden the use of LED bulbs because of their so many
advantages, limited luminance needs improvement.
SUMMARY OF THE INVENTION
[0007] According to an aspect of the invention, there is provided
an LED light bulb. The LED light bulb has a hollow base, a hollow
shell and at least two LEDs. The base has a closed end, an open end
and a sleeve therebetween. The hollow shell is connected to the
open end of the base. The LEDs are vertically arranged within the
shell, for connecting to a DC power source.
[0008] The sleeve may serve as an electrode; the closed end has a
contact point serving as another electrode; both the two electrodes
are connected to the input of a power converter, which converts an
AC power to the DC power to be supplied to the LEDs. The bulb
further has an insulating part separating and insulating the two
electrodes. The power converter can be arranged inside the hollow
base or located outside of the bulb.
[0009] The shell may be made of transparent plastics, transparent
glass or similar materials. The sleeve of the base may include
external threading.
[0010] The LED bulb may further include a transparent support for
maintaining the LEDs in a vertically arranged position, and the
transparent support may be a hollow plastic stem, made of
transparent plastics, transparent glass or similar materials.
[0011] The power converter may include a filter circuit, a bridge
rectifier circuit, and a resistor. The bridge rectifier circuit is
connected to the electrodes via the filter circuit, and the output
of the bridge rectifier circuit is connected to LEDs via the
resistor. The LEDs can be connected in parallel or in series. The
LEDs can be vertically stacked within the shell
[0012] The LED bulb according to the present invention, due to the
vertical stacked arrangement, does not increase the distance from
the LEDs to the top of the bulb shell when the bulb shell is bigger
and higher, so luminance or brightness can be guaranteed by varying
the number of LEDs in a bulb. In addition, the LED bulb according
to the present invention consumes less energy than traditional
incandescent or fluorescent bulbs and has a longer life (about
50,000 to 100,000 hours). It is also compatible with the bases of
the existing bulb. Therefore, replacing a traditional bulb with one
according the present invention is convenient and practical.
[0013] In accordance with an aspect of the present invention, there
is provided a bulb, comprising: [0014] a base, said base further
comprising a closed end, an open end and a sleeve therebetween,
wherein said sleeve serves as an electrode and said closed end
comprises a contact point serving as another electrode; [0015] a
hollow shell connected to the open end of the base; and [0016] a
strand of at least two LEDs joined together and substantially
linearly arranged within the shell [0017] wherein said bulb is
adapted for connection to a DC power source.
[0018] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, further
comprising a support for maintaining at least two LEDs in a
substantially linear arranged position.
[0019] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
support comprises a hollow plastic stem adapted to contain the at
least two LEDs.
[0020] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
substantially linear LEDs are oriented in a substantially vertical
direction in relation to said bulb.
[0021] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
base is hollow, and, within the hollow base, the bulb further
comprises a power converter for converting AC power to DC power to
be supplied to the LEDs.
[0022] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein both
the two electrodes are connected to the input of the power
converter; and the bulb further comprises an insulating part
separating and insulating the two electrodes.
[0023] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
power converter comprises a filter circuit, a bridge rectifier
circuit, and a resistor; the bridge rectifier circuit is connected
to the electrodes via the filter circuit, and the output of the
bridge rectifier circuit is connected to LEDs via the resistor.
[0024] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
sleeve of the base comprises external threading.
[0025] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
shell is made of translucent or transparent plastic.
[0026] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
shell is made of translucent or transparent glass.
[0027] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
LEDs are connected in parallel.
[0028] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
LEDs are connected in series.
[0029] In accordance with another aspect of the present invention,
there is provided an LED bulb, the bulb comprising: [0030] a base,
said base further comprising a closed end, an open end and a sleeve
therebetween, wherein said sleeve serves as an electrode and said
closed end comprises a contact point serving as another electrode;
[0031] a hollow shell connected to the open end of the base; and
[0032] at least two substantially linear strands of LEDs wherein
each substantially linear strand of LEDs further comprises at least
two LEDs [0033] wherein said bulb is adapted for connection to a DC
power source.
[0034] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein said
at least two substantially linear strands are joined together at
one or more points along the length of said substantially linear
strands.
[0035] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein said
substantially linear strands are joined to form an array whereby
each strand points in a different direction within said
compartment.
[0036] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein said
substantially linear strands are each oriented in a substantially
vertical orientation within said compartment.
[0037] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
LEDs are connected in parallel within each strand.
[0038] In accordance with another aspect of the present invention,
there is provided the bulb of the present invention, wherein the
LEDs are connected in series within each strand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The embodiments of the invention will be better understood
by the detailed description thereof, with reference to the
accompanying drawings, wherein like reference numerals refer to the
like elements throughout, in which:
[0040] FIG. 1 is a perspective view of an LED bulb according to the
prior art;
[0041] FIG. 2 is a perspective view of another LED bulb according
to the prior art;
[0042] FIG. 2A is a perspective view of a portion of the prior art
bulb illustrated in FIG. 2 and accordingly is prior art;
[0043] FIG. 3 is a perspective view of an LED bulb in accordance
with one embodiment of the present invention;
[0044] FIG. 3A is a perspective view of an LED bulb in accordance
with another embodiment of the present invention;
[0045] FIG. 4 is an electrical circuit of one part of the bulb of
FIG. 3;
[0046] FIG. 5A is a perspective view of an LED bulb in accordance
with another embodiment of the present invention;
[0047] FIG. 5B is a perspective view of an LED bulb in accordance
with another embodiment of the present invention;
[0048] FIG. 6 is a side view of an LED bulb in accordance with a
decorative bulb embodiment of the present invention illustrating
the typical bulb surface of a Christmas bulb; and
[0049] FIG. 7 is a section of the bulb illustrated in FIG. 6
illustrating the interior components of the bulb.
DETAILED DESCRIPTION OF THE INVENTION
[0050] FIG. 1 illustrates an LED bulb according to the prior art.
The LED bulb, generally shown as 10, comprises a hollow base 20 and
a hollow shell or sometimes referred to as an envelope 30. For the
instant application, the entire article illustrated, for example in
FIG. 1, is called a bulb. The LED inside the bulb, for example LED
110, is called an LED. The base 20 has an open end 50, a closed end
60 and a sleeve 70 between the ends 50 and 60. The sleeve 70 has
external threading 80 so as to match internal threading in a bulb
holder (8171 in FIG. 7) for installment. The sleeve 70 serves as an
electrode. In the central part of the closed end 60 is located a
contact point or portion, serving as another electrode 90, and an
insulating portion (not shown) separates and insulates the two
parts 70 and 90. When the LED bulb 10 is installed in a bulb
holder, such as in a desk lamp, parts 70 and 90, acting as
electrodes, are connected to the electrical contact points in the
bulb holder. The electrical contact points in the bulb holder are
typically further connected to a plug or switch in order to provide
electricity to the bulb thereby causing the LED's to light up.
[0051] The follow back shell or envelope 30 is connected to open
end 50 of base 20 and thus forms an enclosed compartment 100
together with the closed end 60 of the base 20. Within the
compartment 100, the bulb 10 comprises at least one an LED 110.
Corresponding to the sleeve portion 70 in the compartment 100 is
located a power converter 120, which converts AC to DC and supplies
energy to at least one LED contained within the bulb 10.
Alternatively, the power converter can be located outside of the
LED bulb and supply DC power directly to multiple LED bulbs each
constructed similarly to the prior art bulb 10 illustrated in FIG.
1.
[0052] FIG. 2 illustrates another prior art LED bulb, 210. It is
similar to the LED bulb in FIG. 1, and the only difference is that
it comprises more than one LED, 2110, more specifically seven LEDs,
within the shell 230. The seven LEDs in the prior art bulb 210 of
FIG. 2 are horizontally fixed on a printed circuit board (PCB)
2111, with presumably a goal to enhance the luminance of the bulb.
However, the distance that can be brightened is not much farther
than a bulb with a single LED, because all of the LEDs are grouped
together in a common place.
[0053] As light waves move away from the light source, the light
waves spread out over a distance and quickly diminish in intensity.
It is known that there is a light intensity decay over distance
with light intensity decreasing quickly as the distance from the
light source increases. The intensity of light is the power per
unit of area. Area increases as the square of the distance
therefore light decreases as the inverse square of the distance.
Light intensity follows an inverse-square law. Therefore if all the
LEDs are in the same or substantially the same horizontal plane,
the brightness or light intensity of the bulb may not increase
significantly between the prior art bulb in FIG. 1 and the prior
art bulb illustrated in FIGS. 2 and 2A despite the additional LEDs
present.
[0054] Furthermore, with more LEDs on a PCB, the bulb shell must be
big enough to accommodate them. Since a bulb (for example bulb 10
or bulb 210) typically has a smaller diameter than its height (as
illustrated), then a horizontal distribution of LEDs on a PCB will
be limited by the size of the bulb shell the number of LEDs present
in.
[0055] FIG. 3 is an illustration of an LED bulb in accordance with
one embodiment of the present invention. The LED bulb 310 comprises
a hollow base 320 with an open end 350, a closed end 360 and a
sleeve 370 therebetween. A hollow shell 330 is connected to the
open end 350 of the base 320, and a compartment 3100 formed by the
shell 330 and the base 320. The sleeve 370 has external threading
380 to be installed in an internally threaded bulb holder. The
sleeve 370 serves as one electrode. The closed end 360 has a
contact portion or point 390 serving as another electrode. An
insulating part (8171 in FIG. 7), made of rubber or other
insulating material, separates and insulates the two parts 370 and
390. In the sleeve portion 370 of the compartment 3100 is located a
power converter 3120 for converting AC to DC and supplying DC power
to the LEDs.
[0056] Unlike the prior art bulb in FIG. 1, the particular example
illustrated by bulb 310 comprises three LEDs 3110 contained within
the compartment 3100 so as to increase the luminance created by the
bulb. The LEDs 3110 are stacked such that for all but the last LED
in each strand, the envelope top end of any given LED of a strand
substantially faces the base of an adjacent LED in the strand and
connected in series with each other and also connected in series
with the power converter. Although FIG. 3 illustrates three LEDs in
the bulb, the number of LEDs contained in the bulb can vary from
two to any number that can be arrayed within compartment 3100
depending on the dimensions of the bulb shell 330. Preferred
embodiments comprise at least 2 LEDs.
[0057] The LED bulb 310 may further comprise a support. A support
comprises any structure which abuts or surrounds the at least two
LEDs in linear arrangement to support a vertical orientation or a
particular direction. An example of a suitable support is
illustrated in FIG. 3 illustrating a hollow transparent stem 3130
to support and maintain the LEDs 3110 in a substantially vertical
alignment or linear alignment. The support can be made of
translucent or transparent materials such as plastics or glass. It
can be cloudy or clear or colored or colorless. The bulb shell can
also be made of translucent or transparent glass or plastics and it
can be cloudy or clear or clear or colored or colorless.
[0058] Referring to FIG. 4, the power converter 3120 comprises a
filter circuit 4210, and a bridge rectifier circuit 4220, and a
resistor 4230. The filter circuit further comprises a resistor 4212
and a capacitor 4214, connected in parallel. The bridge rectifier
circuit 4220 is connected to the electrodes (power supply) via the
filter circuit 4210, and the output of the bridge rectifier circuit
4220 is connected to LEDs 3110 via the resistor 4230. Thus the
alternative current flowing to the LED bulb from the power supply
connected to the plug of the bulb holder can be converted to direct
current needed by the LEDs 3110, so as to cause the LEDs to emit
light.
[0059] The power adaptor can also be located outside of the LED
bulb and can be adapted to supply DC power directly to one or
multiple LED bulbs. Furthermore, those skilled in the art will
understand that other kinds of power converters and/or filter
circuits can also be used. The base can be of bi-pin type instead
of the screw base as illustrated herein, or any other type of lamp
base with inner space no less than E-12 type lamp base. The
vertical arrangement of the LEDs is generally linear and can extend
substantially vertical or can be pointed in a particular direction.
In a substantially vertical embodiment, the arrangement need not be
precisely vertical, indeed the LEDs may be offset from each other
by a few degrees, or the whole stacked arrangement of LEDs may be
offset from the vertical position by a few degrees. In either case,
a person skilled in the art will understand that such variances are
acceptable in the operation of the LED bulb of the present
invention.
[0060] FIG. 3A is an illustration of an LED bulb in accordance with
another embodiment of the present invention. The LED bulb 710
comprises a hollow base 720 with an open end 750, a closed end 760
and a sleeve 770 therebetween, a hollow shell 730 connected to the
open end 750 of the base 720, and a compartment 7100 formed by the
shell 730 and the base 720. The sleeve 770 has external threading
780 to be installed in an internally threaded bulb holder. The
sleeve 770 serves as one electrode. The closed end 760 has a
contact portion or point 790 serving as another electrode. An
insulating part (8171 in FIG. 7), made of rubber or other
insulating material, separates and insulates the two parts 770 and
790. In the sleeve portion 770 of the compartment 7100 is located a
power converter 7120 for converting AC to DC and supplying DC power
to the LEDs.
[0061] The bulb 710 in FIG. 3A further comprises more than one
substantially linear strand of LEDS. In the specific embodiment
illustrated in FIG. 3A three strands are illustrated and each is
referred to by reference numeral 7140. Each strand 7140 comprises
in this specific embodiment, three LEDs 7110. The number of LEDS
per strand may vary and the number of strands may vary all
contained within compartment 7100 so as to increase the luminance
created by the bulb. Each LED comprises a base 7142 having
electrical terminals 7143 and an envelope 7141 extending from the
base to the envelope top end distal from the base. The LEDs 7110 in
each strand 7140 are joined in a linear orientation. They are
connected in series with each other and also connected in series
with the power converter. In the bulb 710 in FIG. 3A, the strands
7140 are each oriented in a substantially linear and vertical
orientation within the compartment 7100 such that for all but the
last LED in each strand, the envelope top end of any given LED of a
strand substantially faces the base of an adjacent LED in the
strand. Though FIG. 3A illustrates three strands each having three
LEDs in the bulb, the number of strands and LEDs contained in the
bulb can vary from two to any number that can be contained within
compartment 7100 depending on the dimensions of the bulb shell.
[0062] FIG. 5A is an illustration of an LED bulb in accordance with
another embodiment of the present invention. The LED bulb 510
comprises a hollow base 520 with an open end 550, a closed end 560
and a sleeve 570 therebetween, a hollow shell 530 connected to the
open end 550 of the base 520, and a compartment 5100 formed by the
shell 530 and the base 520. The sleeve 570 has external threading
580 to be installed in an internally threaded bulb holder. The
sleeve 570 serves as one electrode. The closed end 560 has a
contact portion or point 590 serving as another electrode. An
insulating part (8171 in FIG. 7), made of rubber or other
insulating material, separates and insulates the two parts 570 and
590. In the sleeve portion 570 of the compartment 5100 is located a
power converter 5120 for converting AC to DC and supplying DC power
to the LEDs.
[0063] The specific embodiment illustrating bulb 510 FIG. 5A
illustrates three substantially linear strands 5140, each strand
comprising three LEDs 5110 contained within the compartment 5100
thereby increasing and enhancing the luminance created by the bulb.
In contrast to the strands 7140 in FIG. 3A, the strands 5140 in
FIG. 5A are joined to form an array whereby each strand 5140 points
in a different direction within compartment 5100. The shell 530 in
FIG. 5A is larger than the shell 730 in FIG. 3A in order to
accommodate the arrangement of the strands 5140. The LEDs 5110 are
stacked such that for all but the last LED in each strand, the
envelope top end of any given LED of a strand substantially faces
the base of an adjacent LED in the strand and connected in series
with each other and also connected in series with the power
converter. A strand 5140 may be joined together with the other
strands 5140 at one or more points along the length of the strand
5140. Though FIG. 5A illustrates three strands each having three
LEDs in the bulb, the number of strands and LEDs contained in the
bulb can vary from one to any number that can be arrayed within
compartment 5100. There can be a number of strands each having at
least two LEDs. The strands need not have the same number of LEDs
but on the other hand they may have the same number of LEDs.
[0064] FIG. 5B is an illustration of an LED bulb in accordance with
another embodiment of the present invention. The LED bulb 610
comprises a hollow base 620 with an open end 650, a closed end 660
and a sleeve 670 therebetween, a hollow shell 630 connected to the
open end 650 of the base 620, and a compartment 6100 formed by the
shell 630 and the base 620. The sleeve 670 has external threading
680 to be installed in an internally threaded bulb holder. The
sleeve 670 serves as one electrode. The closed end 660 has a
contact portion or point 690 serving as another electrode. An
insulating part (8171 in FIG. 7), made of rubber or other
insulating material, separates and insulates the two parts 670 and
690. In the sleeve portion 670 of the compartment 6100 is located a
power converter 6120 for converting AC to DC and supplying DC power
to the LEDs.
[0065] The bulb 610 further comprises three substantially linear
strands 6140, each strand comprising three LEDs 6110 contained
within the compartment 6100 so as to increase the luminance created
by the bulb. Unlike the strands 7140 in FIG. 3A, the strands 6140
in FIG. 5B are joined to form an array whereby each strand 6140
points in a different direction within compartment 6100. The shell
630 in FIG. 5B is larger than the shell 730 in FIG. 3A in order to
accommodate the arrangement of the strands 6140. The LEDs 6110 are
stacked such that for all but the last LED in each strand, the
envelope top end of any given LED of a strand substantially faces
the base of an adjacent LED in the strand and each strand 6140 is
connected to the other strands 6140 such that the connection
between strands 6140 occurs between LEDs 6110 closest in proximity
to the sleeve portion 670. Though FIG. 5B illustrates three strands
each having three LEDs in the bulb, the number of strands and LEDs
contained in the bulb can vary from one to any number that can be
arrayed within compartment 6100.
[0066] FIGS. 6 and 7 are illustrations of an LED bulb in accordance
with another embodiment of the present invention. The LED bulb 810
comprises a hollow base 820 with an open end 850, a closed end 860
and a sleeve 870 therebetween, a hollow shell 830 connected to the
open end 850 of the base 820, and a compartment 8100 formed by the
shell 830 and the base 820. The shell 830 has a thickness 8170 and
an outer surface 8180. The sleeve 870 has external threading 880 to
be installed in an internally threaded bulb holder. The sleeve 870
serves as one electrode. The closed end 860 has a contact portion
or point 890 serving as another electrode. An insulating part 8171,
made of rubber or other insulating material, separates and
insulates the two parts 870 and 890. In the sleeve portion 870 of
the compartment 8100 is located a power converter 8120 for
converting AC to DC and supplying DC power to the LEDs. The power
converter is connected to point 890 by wire 8165 and to sleeve 870
by wire 8166.
[0067] The particular example illustrated by bulb 810 in FIGS. 6
and 7 comprises two LEDs 8110 contained within the compartment 8100
so as to increase the luminance created by the bulb. The LEDs 8110
are stacked such that for all but the last LED in each strand, the
envelope top end of any given LED of a strand substantially faces
the base of an adjacent LED in the strand and connected in series
with each other by wires 8160 and also connected in series with the
power converter. The bulb in FIGS. 6 and 7 has a traditionally
narrowed tip end 8150 consistent with decorative bulbs of the
holiday seasons. Although FIGS. 6 and 7 illustrate two LEDs in the
bulb, the number of LEDs contained in the bulb can vary from two to
any number that can be linearly contained within compartment 8100
and in this embodiment the strand of two LEDs is arranged in a
substantially vertically orientation.
[0068] A globe bulb may be used, for example in Halloween lights
may which may be shaped like a pumpkin. Other arrangements of
single substantially linear strands and multiple substantially
linear strands would be known to a person skilled in the art and
would be suitable for bulbs of varying sizes and shapes.
[0069] Though in the embodiment illustrated herein the LEDs are
connected in series, those skilled in the art will understand that
the LEDs can also be connected in parallel. However, even though
the LED bulb can contain a large number of LEDs because the voltage
drop across each LED is small, due to the difficulties of
constructing a circuit with LEDs in parallel, the number of LEDs
that can be connected in parallel is limited by the amount of the
voltage drop.
[0070] By stacking LEDs in substantially linear strands arranged
such that for all but the last LED in each strand, the envelope top
end of any given LED of a strand substantially faces the base of an
adjacent LED in the strand, an LED bulb of the present invention is
able to distribute light evenly within the entirety of the bulb
compared to the prior art including where the bulb is pointed such
as in a Christmas tree bulb or the bulbs of outdoor lights which
are strung at Christmas. This is possible because in accordance
with an advantage of the present invention the distance from any
location in a bulb to the closest LED to that location varies less
in the bulb of the present invention than in a bulb of the prior
art. For example, the distance between the top of the bulb shell
and an LED fixed to the PCB in the prior art shown in FIG. 2 is
much greater than the distance from the top of the bulb shell to
the top-most LED in the stacked arrangement shown in FIG. 3. In
this example, light from the top LED in the stack does not have to
travel as far in the present invention to reach the top of the bulb
shell, and therefore allows that location to appear brighter than
it does in the prior art. In practice, this means that an LED bulb
of the present invention using the same number of LEDs as the prior
art bulb from FIG. 2 will appear brighter, especially when viewed
from the side or from a long distance away.
[0071] The LED bulb of the present invention has other advantages
over the prior art. It is possible to create larger bulbs while
maintaining even brightness distribution by using multiple linear
stacks oriented in substantially vertical or oriented diagonally,
of LEDs arranged side-by-side. In this way, light can be
distributed more evenly throughout the bulb, regardless of the size
of the bulb, simply by adding more stacks of LEDs beside one
another in the bulb.
[0072] It was also determined that the cost of manufacturing an LED
bulb of the present invention that uses 2 to 4 LEDs is lower than
the cost of manufacturing an LED bulb of the prior art using the
same number of LEDs.
[0073] Note that it is possible to create an LED bulb of the prior
art using multiple PCBs, each having multiple LEDs, where each PCB
is positioned parallel to the other PCBs, both above and below the
single PCB shown in FIG. 2. Depending on the arrangements of the
LEDs on the PCBs, it is possible to increase the brightness of the
LED bulb of the prior art in this way. However, in order to achieve
brightness that is similar to the brightness of the LED bulb of the
present invention, such a stacked-PCB design would require more
LEDs and have increased manufacturing cost compared to the LED bulb
of the present invention.
[0074] A test was carried out on an LED bulb of the present
invention where the LEDs in the bulb were connected in a series
arrangement as shown in FIG. 4 to determine how many LEDs could be
used in that arrangement. For the test, an input voltage of 110V
was used. In order to achieve the desired current of 10 mA to 13 mA
for proper operation of the LEDs, an input resistor with a
resistance of 560 Ohms was used causing the voltage to drop to 90V.
Since the maximum voltage drop across each single LED was 3.4V, the
maximum number of LEDs that could be used in the circuit was
determined by the calculation 90V divided by 3.4V per LED, or 26.47
LEDs. Therefore the maximum number of LEDs arranged in series was
determined to be 26. However, during testing, it was found that the
input resistor will become over-heated when there are more than 23
LEDs connected in series. For safety concerns, the maximum number
of LEDs that were connected in series in this test was 20. It
should be noted that the number of LEDs vertically positioned in a
bulb is also limited by the size of the bulb shell.
[0075] In another test, it was shown that the LED bulb according to
the embodiments of the present invention can provide energy savings
of up to 90% compared with a traditional incandescent light bulb.
In this test, a LED bulb of the present invention having 3 LEDs was
compared with 120V 3W C7 and C9 type incandescent lamp bulbs, which
are known to the applicant to be amongst the lowest power consuming
incandescent light bulbs in the North American market. The test
results showed that the LED bulb consumed power in the range of 0.3
W to 0.35 W, which is a savings of nearly 90% compared to the 3W
consumed by the C7 and C9 incandescent bulbs.
[0076] The LED bulb can be used in various applications, such as
household, work plant, show window, store, street display, exterior
decorations. The LED bulbs of the present invention are applicable
in many setting requiring light and can provide enhanced
luminescence and brightness over prior art LED bulbs at a lower
cost of manufacturing as described herein. The luminance of the LED
bulb can be adjusted by including various LEDs in the bulb.
[0077] While this invention has been illustrated and described in
connection with only certain embodiments thereof, various changes,
modifications and amendments can occur to those skilled in the art
without departing from the spirit and the scope of the invention as
defined in the appended claims.
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