Abstrict An exit sign comprising a housing and a plurality of red and green
color LEDs having the capability of being selectively activated
to produce either red light or green light. The plurality of LEDs
are mounted in a mutual lighting association in the housing. A switch
is manually operable to selectively activate the plurality of red
color LEDs to produce the red light and in the alternative, to selectively
activate of the plurality of the green color LEDs to produce the
green light. Means for passing light from the selected red light
or selected green light in the form of indicia symbolizing an exit
enables viewing by an observer, such means include a stencil having
four independent letters forming the word EXIT. DC circuitry is
in operative electrical connection with the plurality of LEDs. A
source of DC electrical power activates the DC circuitry. The plurality
of LEDs can be monochrome red LEDs and monochrome green LEDs or
in the alternative, the plurality of LEDs can be bicolor LEDs having
the capability of producing red light or green light. Red light
and green light can be simultaneously emitted so as to produce yellow
light. An emergency power backup battery is connected to the plurality
of color LEDS. Means for producing emergency light is optional.
Claims What is claimed is:
1. An exit sign comprising: a housing, a plurality of LEDs having
the capability of being selectively activated to produce either
red light or green light, said plurality of LEDs being mounted in
mutual lighting association in said housing, means for selective
activation of said plurality of LEDs to produce either said red
light or said green light, means for passing light from selected
said red light or selected said green light in the form of indicia
symbolizing an exit enabling viewing by an observer, means for optically
diffusing said light positioned in said housing juxtapositioned
to said plurality of LEDs and said means for passing light, DC circuitry
in operative electrical connection with said plurality of LEDs,
and a source of DC electrical power activating said DC circuitry.
2. The exit sign according to claim 1 wherein said plurality of
LEDs further having the capability of being selectively activated
by said means for selective activation to simultaneously emit both
said red light and said green light so as to produce yellow light,
and wherein said means for selective activation of said plurality
of LEDs to produce both of said red light and said green light includes
means to produce both said red light and said green light so as
to produce said yellow light, wherein said yellow light passes through
said means for passing light enabling viewing of said indicia by
an observer.
3. The exit sign according to claim 1 wherein said plurality of
LEDs includes a plurality of monochrome red LEDs and a plurality
of monochrome green LEDs, each said monochrome red LED having the
capability of being activated by said means for selective activation
to produce said red light, and each of said monochrome green LED
having the capability of being activated by said means for selective
activation to produce said green light.
4. The exit sign according to claim 1 wherein said plurality of
LEDs includes a plurality of bicolor LEDs, each said bicolor LED
having the capability of being activated by said means for selective
activation to produce either said red light or said green light.
5. The exit sign according to claim 1 wherein said means for optically
diffusing said light is an optical diffuser.
6. The exit sign according to claim 1 wherein said means for passing
light in the form of indicia is a non-transparent stencil defining
light passageway openings forming said indicia, said light passing
through said light passageway openings enabling viewing of said
indicia by an observer.
7. The exit sign according to claim 1 wherein said means for passing
light in the form of indicia is a translucent stencil having non-transparent
areas and transparent areas, said transparent areas forming said
indicia, said light passing through said transparent areas enabling
viewing of said indicia by an observer.
8. The exit sign according to claim 1 wherein said indicia symbolizing
an exit is four independent letters forming the word EXIT.
9. The exit sign according to claim 1 wherein said indicia includes
at least one symbol indicating an exit.
10. The exit sign according to claim 9 wherein said at least one
symbol is a chevron arrow.
11. The exit sign according to claim 1 wherein said means for
selective activation to produce either of said red light or said
green light is a switch.
12. The exit sign according to claim 11 wherein said switch includes
the capability to simultaneously activate both said red light and
said green light so as to produce yellow light.
13. The exit sign according to claim 1 further including battery
means for providing emergency DC power to said plurality of LEDs
in the event of failure of electrical DC power.
14. The exit sign according to claim 13 further including means
for providing emergency light including a plurality of monochrome
LEDs, said means for producing emergency light being in electrical
connection to said battery means.
15. An exit sign comprising: a housing, a plurality of monochrome
red LEDs and a plurality of monochrome green LEDs having the capability
of being selectively activated to produce either red light or green
light, said plurality of monochrome red LEDs and said monochrome
green being mounted in mutual lighting association in said housing,
means for selective activation of either said plurality of monochrome
red LEDs to produce said red light or said plurality of monochrome
green LEDs to produce said green light, means for passing light
from selected said red light or selected said green light in the
form of indicia symbolizing an exit enabling viewing by an observer,
means for optically diffusing said red light or said green light
positioned in said housing juxtapositioned to said plurality of
monochrome red LEDs and said plurality of monochrome green LEDs
and said means for passing light, DC circuitry in operative electrical
connection with said plurality of monochrome red LEDs and said plurality
of monochrome green LEDs, and a source of DC electrical power activating
said DC circuitry.
16. The exit sign according to claim 15 wherein said plurality
of monochrome red LEDs and monochrome green LEDs have the capability
of being selectively activated by said means for selective activation
to simultaneously emit both said red light and said green light
so as to produce yellow light, wherein said yellow light passes
through said means for passing light enabling viewing of said indicia
by an observer.
17. The exit sign according to claim 15 wherein said means for
passing light in the form of indicia is a non-transparent stencil
defining light passageway openings forming said indicia, said light
passing through said light passageway openings enabling viewing
of said indicia by an observer.
18. The exit sign according to claim 15 wherein said means for
passing light in the form of indicia is a translucent stencil having
non-transparent areas and transparent areas, said transparent areas
forming said indicia, said light passing through said transparent
areas enabling viewing of said indicia by an observer.
19. The exit sign according to claim 15 wherein said indicia symbolizing
an exit is four independent letters forming the word EXIT.
20. The exit sign according to claim 15 wherein said indicia includes
at least one symbol indicating an exit.
21. The exit sign according to claim 20 wherein said at least
one symbol is a chevron arrow.
22. The exit sign according to claim 15 wherein said means for
selective activation of said plurality of LEDs to produce either
said red light and said green light is a switch.
23. The exit sign according to claim 22 wherein said switch includes
the capability to simultaneously activate both said red light and
said green light so as to produce yellow light.
24. The exit sign according to claim 15 wherein said means for
optically diffusing said red and green light is an optical diffuser.
25. The exit sign according to claim 15 further including battery
means for providing emergency DC power to said plurality of monochrome
red LEDs and said plurality of monochrome green LEDs in the event
of failure of electrical DC power.
26. The exit sign according to claim 15 further including means
for providing emergency light including a plurality of monochrome
LEDs, said means for producing emergency light being in electrical
connection to said battery means.
27. An exit sign comprising: a housing, a plurality of bicolor
red and green LEDs having the capability of being selectively activated
to produce either red light or green light, said plurality of bicolor
red and green LEDs being mounted in mutual lighting association
in said housing; means for selective activation of said plurality
of bicolor LEDs to produce either said red light or said green light,
means for passing light from selected said red light or selected
said green light in the form of indicia symbolizing an exit enabling
viewing by an observer, means for optically diffusing said red light
or said green light positioned in said housing juxtapositioned to
said plurality of bicolor red and green LEDs and said means for
passing light, DC circuitry in operative electrical connection with
said plurality of bicolor red and green LEDs, and a source of DC
electrical power activating said DC circuitry.
28. The exit sign according to claim 27 wherein said plurality
of bicolor red and green LEDs have the capability of being selectively
activated by said means for selective activation to simultaneously
emit both said red light and said green light so as to produce yellow
light, wherein said yellow light passes through said means for passing
light enabling viewing of said indicia by an observer.
29. The exit sign according to claim 27 wherein said means for
passing light in the form of indicia is a non-transparent stencil
defining light passageway openings forming said indicia, said light
passing through said light passageway openings enabling viewing
of said indicia by an observer.
30. The exit sign according to claim 27 wherein said means for
passing light in the form of indicia is a translucent stencil having
non-transparent areas and transparent areas, said transparent areas
forming said indicia, said light passing through said transparent
areas enabling viewing of said indicia by an observer.
31. The exit sign according to claim 27 wherein said indicia symbolizing
an exit is four independent letters forming the word EXIT.
32. The exit sign according to claim 27 wherein said indicia includes
at least one symbol indicating an exit.
33. The exit sign according to claim 32 wherein said at least
one symbol is a chevron arrow.
34. The exit sign according to claim 27 wherein said means for
selective activation of said plurality of bicolor LEDs to produce
either said red light or said green light is a switch.
35. The exit sign according to claim 34 wherein said switch includes
the capability to simultaneously activate both said red light and
said green light of said plurality of bicolor red and green LEDs
so as to produce yellow light.
36. The exit sign according to claim 27 wherein said mean for
optically diffusing said red and green light is an optical diffuser.
37. The exit sign according to claim 27 further including battery
means for providing emergency DC power to said plurality of bicolor
red and green LEDs in the event of failure of electrical DC power.
38. The exit sign according to claim 27 further including means
for providing emergency light including a plurality of monochrome
LEDs, said means for producing emergency light being in electrical
connection to said battery means.
Description RELATED U.S. APPLICATION DATA
[0001] This patent application claims benefit of U.S. Provisional
Application No. 60/465822 filed on Apr. 25 2003 entitled, "Tri-Color
LED Lamp for Illuminated Signage".
FIELD OF THE INVENTION
[0002] The present invention relates generally to color light emitting
diode lamps used in illuminated signs, and more particularly to
illuminate emergency exit signs.
BACKGROUND OF THE INVENTION
[0003] Originally, an exit sign used standard incandescent lamps.
The earliest alternatives to incandescent lamps were radioactive
tritium gas and compact fluorescent lamps. In 1985 light-emitting
diodes (LEDs) were introduced for use in exit signs.
[0004] The most cost-effective alternative today over the exit
signs that use incandescent lamps are LED exit signs. A standard
LED exit sign generally uses only about 1 to 5 watts of power per
surface and costs less than $5.00 per year to operate depending
on the model and local utility costs. Because LEDs also last considerably
longer than incandescent lamps, life cycle savings are dramatic.
When an LED exit sign is used instead of an incandescent exit sign,
the cost saving multiple over a ten-year period including initial
costs, energy expenditures, and maintenance requirements will be
in the range of five times.
[0005] There are currently several different types of LED exit
signs available in the marketplace using a variety of LEDs in different
configurations. There are a great number of LED sign manufacturers
competing in the market. As a result, there is a wide range in price,
quality, and energy consumption. Some LED signs use as few as 6
LEDs, others use 18 to 35 LEDs, and some use up to 200 LEDs. The
rated energy consumption can thus range from as little as 1 watt
up to 8 watts.
[0006] Under National Fire Protection Association (NFPA), National
Electrical Code (NEC), Underwriters Laboratories (UL) and local
fire and building codes for each state, buildings that provide public
access are required by law to have signs therein identifying the
exits. These emergency signs are required to exhibit a specific
amount of illumination and often times are required to have an emergency
backup power source to provide emergency illumination to the exit
sign for a specified period of time when electrical power to the
building is interrupted to allow sufficient time for persons in
the building to vacate. LED exit signs are presently available primarily
with red or green color LEDs, or other approved colors as required
by local ordinances or municipalities and depending on state and
city codes.
[0007] No LED exit sign presently exists that is commercially manufactured
to the best of my knowledge that provides a choice of either red
or green color LEDs along with a switch to select the color of the
exit sign indicia that is legally required by the particular jurisdiction.
In the selective color LED lamp of the present invention, the switch
can selectively turn on the red color LEDs to produce a red color
exit sign indicia, or selectively turn on the green color LEDs to
produce a green color exit sign indicia. In addition, the LED lamp
of the present invention can selectively turn on both the red and
green color LEDs simultaneously to produce a yellow color exit sign
indicia. Exit signs usually include a stencil having perforations
that define indicia through which the LED light passes and which
is readable by an observer. Existing stencil signs have solid colored
green or red diffuser panels behind opaque sections with the letters
EXIT cut out. Other exit signs can include a stencil manufactured
out of a clear lens with the indicia or background masked with a
red, green, or other color ink. The word EXIT is usually white in
this case against the color background. The indicia generally form
the letters of the word EXIT and include removable or permanent
chevron arrows located on opposite sides of the word EXIT. Other
words, symbols, or idiogram indicia can indicate an exit. Among
these are words or symbols in non-English speaking countries that
have an analogous meaning to the word EXIT in English.
[0008] The present invention provides an LED lamp that enables
a user to selectively, or optionally, produce distinct color outputs.
The selective color LED lamp is designed for use in illuminated
signs generally including emergency exit signs, but also other types
of illuminated signs that can be used in different locations. The
use of the selective color LED lamp will allow the emergency signage
to comply with all local fire and building code requirements. An
LED exit sign manufacturer, wholesaler, and retailer can stock only
one basic version of the selective color LED lamp exit sign thereby
reducing manufacturing, inventory, and shipping costs. The selective
color LED lamp is designed to replace existing incandescent and
single color LED lamps. It can be used directly in sockets of existing
emergency exit signs as retrofit LED lamps, or as the main light
source in new emergency exit signs and other illuminated signs.
Besides using the selective color LED lamp of the present invention
in emergency exit signs, the selective color LED lamp can be used
in illuminated advisory, directional, instructional, warning, and
safety demarcation signs. In the latter uses, other selective colors
can be used other than the red, green, and yellow colors of the
selective color LED lamp. Another area where the selective color
LED lamp of the present invention can be used is in warning and
instructional lighting markers used in many truck-loading docks
around the country.
[0009] It is an object of the present invention to provide a selective
color LED lamp wherein one of the color red or the color green can
be selected for general signage lighting applications incorporating
light emitting diodes as the main light source for use in existing
and newly manufactured signage lighting fixtures.
[0010] Another object of the present invention is to provide such
a selective color LED lamp that can readily replace the incandescent
and compact fluorescent lighting units offering energy efficiency,
longer life with zero mercury, zero disposal costs, and zero hazardous
waste. The present invention can be used with all types of illuminated
signage.
[0011] Yet another object of the present invention is to provide
a selective color LED lamp that will easily produce a red color
or green color while substantially using a low number of color LEDs
wherein such use is in the field of emergency exit signs.
[0012] Yet another object of the present invention is to provide
a selective color LED lamp that will easily produce a red color
or green color or a mixed red and green color to produce the color
yellow while using a relatively low number of colored LEDs wherein
such use is in the field of emergency exit signs.
[0013] A further object of the present invention is to provide
a selective color LED retrofit lamp containing integral electronic
circuitry that can be readily and economically fabricated from simple
electronic components for easy adaptation for use with existing
illuminated signage.
[0014] And yet a further object of the present invention is to
provide a selective color LED lamp combined with surge suppression,
uniform illumination, battery backup, and low power consumption
to be readily and economically fabricated from simple components,
for use in newly manufactured and multipurpose illuminated emergency
signage that is readily adaptable to comply with fire and building
code.
[0015] A final object of the present invention is to provide a
selective color LED lamp for use in newly manufactured illuminated
signage with optional emergency lights integrally and operationally
mounted with the main lamp unit.
BRIEF SUMMARY OF THE INVENTION
[0016] The selective color retrofit LED lamp comprises an array
of red color LEDs and an array of green color LEDs, each LED in
each array is connected in a series and parallel relationship with
similar color LEDs. Alternating current (AC) voltage is converted
to direct current (DC) voltage by bridge rectifiers to power the
LEDs. Switches will be provided to turn on or to select for operation
only the array of red color LEDs or only the array of green color
LEDs. Optionally, both arrays of red and green color LEDs can be
turned on to emit light at the same time, the latter selection resulting
in the production of the color yellow. The LEDs are mounted onto
a rigid circuit board with or without an external housing. The AC
power to the selective color retrofit LED lamp can terminate in
any standard lamp configuration including, but not limited to bi-pin,
medium screw base, candelabra base, etc. This selective color retrofit
LED lamp can be used in single and double panel mount exit signs,
edge mount exit signs, stencil exit signs, panel mount exit signs
fitted with emergency lights, and other illuminated signage.
[0017] The selective color LED lamp of the present invention can
be used in newly manufactured illuminating signage as well. This
selective color LED lamp in combination with a number of other components
including a step-down transformer to convert 120/220/277 VAC to
a lower voltage to power the LEDs and to serve as a voltage suppresser;
a battery backup system with testing capability that is charged
by the AC power input; a fixture housing or body; a fixture mount;
background stencil and lettering or symbol indicia; at least one
optical diffuser; and optional integral emergency lights, all combine
to form a selective color LED illuminating sign of the present invention.
[0018] U.S. Pat. No. 6567010 issued to Lin and Zhu on May 20
2003 discloses a traffic signal head with individual activation
of 1) red light LED generating elements and green light LED generating
elements, and 2) red light LED generating elements and green light
LED generating elements with simultaneous activation of the red
and green light LED generating elements producing yellow light.
The two main claims in Lin set forth the combination of the individual
activations of red, green, and yellow light, a housing, activation
circuitry, and the inventive feature of circuitry for enabling adjustment
of the relative intensity of the yellow light produced by the activation
of the red and green light.
[0019] However, Lin does not disclose, as does the present invention
a combination of elements that includes means for passing selected
red light or selected green light from an array of red LEDs and
an array of green LEDs in the form of indicia symbolizing an exit
and enabling viewing by an observer. Nor does Lin disclose means
for optically diffusing the selected red light or selected green
light positioned in the housing between the array of red LEDs and
the array of green LEDs positioned in the housing, and the means
for passing light in the form of indicia. The present invention
includes yellow light produced by the simultaneous production of
red and green light that also passes through the indicia symbolizing
an exit. There is no adjustment of the relative intensity of the
yellow light. The selected red light or green light is full on or
full off resulting in a yellow light that is either full on or completely
off only.
[0020] The present invention will be better understood and the
objects and important features, other than those specifically set
forth above, will become apparent when consideration is given to
the following details and description, which when taken in conjunction
with the annexed drawings, describes, illustrates, and shows preferred
embodiments or modifications of the present invention, and what
is presently considered and believed to be the best mode of practice
in the principles thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a front view of an assembled selective color
LED exit sign in accordance with the present invention;
[0022] FIG. 1A shows the basic mount structure for the selective
color LED exit shown in FIG. 1 along with two attached emergency
lights along with LED lamps mounted thereto;
[0023] FIG. 1B shows an optical diffuser of the selective color
LED exit sign shown in FIG. 1 before being mounted to the mount
structure shown in FIG. 1A;
[0024] FIG. 1C shows the front face of a stencil defining indicia
indicating an exit that is mounted to the mount structure shown
in FIG. 1 over the optical diffuser of the selective color LED exit
sign shown in FIG. 1B;
[0025] FIG. 1D shows the front face of an alternative stencil;
[0026] FIG. 2 shows the selective color LED exit sign as shown
in FIG. 1 in a simplified form showing one each of a red and green
light beam and one mixed yellow light beam from the combination
of the one red with the one green light beam;
[0027] FIG. 2A shows a chart of the typical dipswitch selections
as related to FIG. 2;
[0028] FIG. 3 shows an isolated schematic block diagram of the
isolated selective color LED lamp of the selective color LED exit
sign shown in FIGS. 1 and 2;
[0029] FIG. 4 shows a schematic block diagram of the selective
color LED exit sign shown in FIGS. 1 and 2 including the selective
color LED lamp shown in FIG. 3;
[0030] FIG. 5 shows the electrical circuit used for the selective
color LED exit sign; and
[0031] FIG. 6 is a schematic block diagram analogous to FIG. 3
that shows an alternative selective color LED lamp with bicolor
red and green LEDs.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Reference is now made to the drawings and in particular
to FIGS. 1-6 in which identical or similar parts are designated
by the same or similar reference numerals throughout.
[0033] A selective color light emitting diode (LED) sign 10 is
shown in FIG. 1-6 and in particular in assembled front view in FIG.
1. Sign 10 includes disassembled elements shown in FIGS. 1A, 1B,
1C, and 1D.
[0034] In particular, FIG. 1A shows a disassembled front view 12
of sign 10 comprising a housing 14 and a flat rear panel 16 mounted
thereto. A canopy 18 attached to the top edge 20 of housing 14 provides
support for hanging the entire sign 10 to a ceiling structure (not
shown). A step-down transformer 22 is mounted at top edge 20 at
one side edge 24 of housing 14 opposite bottom edge 21 and a rechargeable
backup battery 26 is mounted at top edge 20 at the opposed side
edge 28 of housing 14. Optional emergency lights 30A and 30B are
attached to housing side edges 24 and 28 respectively. An array
of thirty-six monochrome color LEDs 32 are horizontally mounted
in a manner known in the art at equal intervals across the area
of top edge 20 of flat rear panel 16 between side edges 24 and 28.
[0035] FIG. 1B shows in isolation the front view of an optical
diffuser 34 known in the art that is secured to housing 14 and positioned
over LEDs 32. FIG. 1C shows a rectangular stencil 36 in front view
taken in isolation that is secured to housing 14 in assembled mode
and positioned over optical diffuser 34 LEDs 32 and rear panel
16. Stencil 36 is also shown in FIG. 1. Stencil 36 is generally
non-transparent and includes four light passageway openings 38A,
38B, 38C and 38D that define the four letters, or four indicia,
in capitalized mode of the word EXIT, respectively, that extend
horizontally in the midarea of stencil 36 through which light beams
projected by LEDs 32 pass through each light passageway opening
38A, 38B, 38C and 38D after passing through optical diffuser 34
for eventual viewing by an observer. Stencil 36 optionally defines
two directional symbols, namely, opposed chevron arrow openings
39A and 39B through which light beams projected by LEDs 32 pass
for eventual viewing by an observer.
[0036] FIG. 1D shows an alternative embodiment of the rectangular
stencil 36 namely stencil 36A in front view taken in isolation
that is secured to housing 14 in assembled mode and positioned over
optical diffuser 34 LEDs 32 and rear panel 16. Stencil 36A is
clear and translucent, but is made non-translucent by a manner known
in the art such as by the application of paint or other masking
medium. Stencil 36A provides four transparent areas 38E, 38F, 38G,
and 38H that define the four letters or four indicia, in capitalized
text mode of the word EXIT, respectively, and that extend horizontally
in the general midarea of stencil 36A through which light beams
projected by LEDs 32 pass through each transparent area 38E, 38F,
38G, and 38H after passing through optical diffuser 34 for eventual
viewing by an observer. Stencil 36A optionally includes other transparent
areas such as two directional symbols, namely, opposed chevron arrows
39A and 39B through which light beams projected by LEDs 32 pass
for eventual viewing by an observer. Other variations of stencils
36 and 36A are possible within the parameters of the present invention.
It should be noted that the alternative stencil 36A itself could
be manufactured out of a diffusion material thereby further reducing
parts by eliminating the need for a separate optical diffuser 34.
[0037] FIG. 2 shows a more detailed view 40 of the disassembled
front view 12 shown in FIG. 1A and wherein thirty-six monochrome
color LEDs 32 include for purposes of exposition twelve red LEDs
32A and twenty-four green LEDs 32B each individually mounted to
and electrically connected to a circuit board 35 that is attached
to housing 14. The relative numbers of LEDs 32A and 32B can vary.
For example, equal numbers of red LEDs 32A and green LEDs 32B can
be used. As shown in FIG. 2 the arrangement of thirty-six LEDs
32 are such that there are two green LEDs 36B located between every
red LED 36A with a green LED 36B positioned at each end of the total
array of thirty-six LEDS 32. The actual number of red color LEDs
32A and green color LEDs 36B can vary depending on the make and
type of LED 32 used as determined by the output beam angle and the
output lumen generated by each LED 32. For purposes of exposition
a single red color beam 42 is produced from a single red LED 32A
and a single green color beam 46 is produced from a single green
LED 32B. A single yellow color beam 44 is produced from a combination
of the red color beam 42 emitted from red LED 32A with the green
color beam 46 emitted from single green LED 32B. Red color beam
42 represents all red color beams and green color beam 46 represents
all green color beams, and yellow color beam 44 represents all yellow
color beams.
[0038] Also seen in FIG. 2 are twenty-eight monochrome LEDs 48A
positioned in a concentric circular arrangement in optional emergency
light 30A mounted to side edge 24 of housing 14 and twenty-eight
monochrome LEDs 48B positioned in a concentric circular arrangement
in optional emergency light 30B mounted to side edge 28 of housing
14. A normally closed DC disconnect test switch 50 is positioned
on circuit board 35 proximate to LEDs 32 to test the battery backup
system, and a DC power status LED 52 is also positioned on circuit
board 35. A normally open DC connect test switch 50A is also positioned
on circuit board 35 which when closed will connect power to LEDs
48A and 48B in emergency lights 30A and 30B respectively.
[0039] A dipswitch 54 containing two separate switches is positioned
on circuit board 35 proximate to and in electrical connection to
LEDs 32. Dipswitch 54 is in electrical connection to circuitry connected
to the circuit board (not shown) and LEDs 32 and is manually operable
to select any one of the following options as shown in dipswitch
settings table 2A as follows:
[0040] 1. Deactivation of any color to selective color LED sign
10;
[0041] 2. Activation of red LEDs 32A so as to produce red color
as represented by red beam 42;
[0042] 3. Activation of green LEDs 32B so as to produce green color
as represented by green beam 46;
[0043] 4. Activation of both red LEDs 32A and green LEDs 32B resulting
in the emission of red and green colors that mix to produce yellow
light as represented by yellow beam 44.
[0044] FIG. 3 shows a schematic block diagram 56 of a selective
color LED lamp 58 taken in isolation. Selective color LED lamp 58
can be used in retrofit applications for existing illuminated signs
or as the main selective color LED lamp in new fixtures. LED lamp
58 basically comprises an alternating current voltage (VAC) power
input 60 that is readily converted into a DC voltage output to power
red and green color LEDs 32A and 32B, respectively, by an AC to
DC converter 62.
[0045] A single main or individual current limiter, or resistor
64 is used to limit the current going into red LEDs 32A and green
LEDs 32B. Red LEDs 32A and green LEDs 32B comprise of LEDs 32 connected
in both a series and a parallel configuration for redundancy. This
is done so that the majority of red LEDs 32A and green LEDs 32B
will remain energized in the event that one or more LEDs 32 in each
array should fail.
[0046] Each of the red LEDs 32A and green LEDs 32B are in direct
communication with a two-position dipswitch 54 previously discussed
that is manually operable to close the power supply circuit and
thereby energize all the red LEDs 32A and green LEDs 32B. Red LEDs
32A can be energized independent of green LEDs 32B, and vice versa.
In the event that both red LEDs 32A and green LEDs 32B are switched
on and energized, a third color, namely, the color yellow, will
appear resulting from the combination of the mixing of the output
color beams from red LEDs 32A with green LEDs 32B. Activated LEDs
32 are connected to ground 66 thereby completing the current path
through red LEDs 32A and green LEDs 32B respectively.
[0047] FIG. 4 shows a schematic block diagram 68 of exit sign 10.
The usual source of power to an emergency exit sign is alternating
current voltage or VAC 60. This voltage can be 120V, 240V, or 277V.
Since the input AC voltage is high, a step-down transformer typified
by step-down transformer 22 also shown in FIG. 2 is used to bring
the input voltage down to a lower operating AC voltage, for example
8VAC. The 8VAC is then passed through AC/DC converter 62 typically
a bridge rectifier.
[0048] The direct current voltage or VDC is then connected to a
momentary DC power disconnect test switch 50 that is normally closed.
The function of DC power disconnect test switch 50 is to test the
electronic circuitry of the backup system to battery 26 by simulating
the interruption of DC voltage power. DC power indicator LED 52
signals the presence of AC voltage power.
[0049] The DC voltage also goes through a charging circuit 70 connected
to rechargeable battery 26 and then to a switching circuit 72. The
output of switching circuit 72 then goes through a main or individual
current limiter 74 and lastly to red LEDs 32A and green LEDs 32B.
The function of switching circuit 72 is to provide power to red
LEDs 32A and green LEDs 32B when normal input DC voltage is present,
but will automatically switch over to battery backup 26 DC power
in the event of input AC power failure. As described before two-position
dipswitch 54 is operable to turn either or both red LEDs 32A and
green LEDs 32B on and off.
[0050] Two separate monochrome LED lights 30A and 30B, respectively,
act as optional emergency lights. The LEDs 48A and 48B for use in
emergency LED lights 30A and 30B are monochrome comprising either
white and/or yellow color LEDs. They are optional and serve as emergency
lighting for the egress and evacuation of buildings or other establishments
in the event of power failure and general lighting is not available.
A separate DC power connect test switch 50A energizes the optional
emergency monochrome LEDs 48A and 48B. The output of switching circuit
72 also goes through current limiter 74A and then to monochrome
LEDs 48A and 48B.
[0051] Momentary DC power status connect switch 50A is normally
open and when depressed will connect the DC voltage power directly
to test optional emergency lights 30A and 30B. In the absence of
AC voltage power or when the DC power disconnect test switch 50
is depressed, backup battery 26 voltage power will kick in to power
both red LEDs 32A and green LEDs 32B as well as providing power
for LEDs 48A and 48B in optional emergency lights 30A and 30B. The
storage capacity of backup battery 26 should provide enough reserve
voltage to power all the LEDs in exit sign 10 including optional
emergency lights 30A and 30B for a duration of 1.5 to 3.0 hours
when there is no AC voltage input. Red LEDs 32A and green LEDs 32B
and LEDs 48A and 48B in emergency LED lights 30A and 30B are connected
to ground 66 thereby completing the current paths through red LEDs
32A and green LEDs 32B and LEDs 48A and 48B in emergency LED lights
30A and 30B.
[0052] FIG. 5 depicts the electrical circuit used for selective
color LED exit sign 10. Step-down transformer 22 shown here as TI
has multiple primary input voltage taps depending on the voltage
available. As mentioned before, these may be 120 volts, 240 volts,
or 277 volts AC. The secondary output voltage of transformer 22
is the same at about 8 volts AC, also as mentioned before. The 8
volts AC are attached to the AC inputs of AC/DC converter 62 shown
here as a bridge rectifier BR1. The negative output of bridge rectifier
BR1 becomes the DC ground 66 while the positive output of bridge
rectifier BR1 serves to deliver power to four main circuits by way
of the normally closed momentary test switch 50 shown here as SW1.
[0053] A first circuit 78 passes DC voltage through current limiter
64 shown here as resistor R1 that limits current to DC power indicator
LED 52 also indicated as LED1. One end of resistor R1 is connected
to the anode of power indicator LED 52 and the cathode of power
indicator LED 52 (LED1) is connected to DC ground 66. DC power indicator
LED 52 lights up when AC input voltage is present and test switch
50 (SW1) is not depressed. Due to the fact that power indicator
LED 52 (LED1) is by nature a diode itself, it prevents reverse current
flow from DC ground 66 back to the positive DC output of bridge
rectifier BR1. Therefore current flows only in one direction from
the anode of DC power indicator LED 52 (LED1) to the cathode of
DC power indicator LED 52 (LED1).
[0054] A second circuit 80 represents the charging circuitry 70
for delivering power to rechargeable battery 26 (BATTERY) for backup
power in case of AC input voltage failure. DC voltage passes through
diode D2 into resistor R2 and directly into the positive terminal
of battery 26 (BATTERY). The negative terminal of battery 26 (BATTERY)
is connected to DC ground 66. Diode D2 prevents the reverse current
flow from battery 26 (BATTERY) back to the positive DC output of
bridge rectifier BR1 and therefore allows current to flow only
in one direction from the anode of diode D2 to the cathode of diode
D2.
[0055] Third circuit 82 includes a complete array of red LEDS 32A
as shown in FIG. 5 comprising individual red LEDs, namely, LED2
to LED2X,Y connected in an electrical series and parallel configuration
for redundancy. Third circuit 82 also includes a complete array
of green LEDs 32B as shown in FIG. 5 comprising individual green
LEDS, namely, LED3 to LED3X,Y also connected in an electrical series
and parallel configuration. This identification of red and green
LEDs sets forth that red LEDs 32A and green LEDs 32B can each comprise
of at least one red LED and at least one green LED connected in
an electrical serial and parallel configuration.
[0056] In addition, third circuit 82 includes monochrome LEDs 48A
and 48B. LEDs 48A is shown in FIG. 5 as comprising of individual
monochrome LEDs, namely, LED4 to LED4X,Y, and LEDs 48B is shown
in FIG. 5 as comprising of individual monochrome LEDs, namely, LED5
to LED5X,Y. This identification of individual monochrome LEDs sets
forth that LEDs 48A and 48B can each comprise of at least one monochrome
LED in an electrical serial and parallel configuration.
[0057] The actual number of red LEDs 32A and green LEDs 32B and
monochrome LEDs 48A and 48B in optional emergency lights 30A and
30B can be the same number or can differ in number.
[0058] Third circuit 82 drives red LEDs 32A, namely, LED2 to LED2X,Y
and green LEDs 32B, namely, LED3 to LED3X,Y during normal operation
when input AC voltage is present and test switch 50 (SW1) is not
depressed. DC voltage passes through diode D1 from the anode side
to the cathode side. Diode D1 prevents the reverse current flow
from LEDs 32A and 32B back to the positive DC output of bridge rectifier
BR1 and therefore allows current to flow only in one direction
from the anode of diode D1 to the cathode of diode D1. DC voltage
passes to red LEDs LED2 to LED2X,Y by way of resistor R4. Likewise
DC voltage passes to green LEDs LED3 to LED3X,Y by way of resistor
R5. Resistors R4 and R5 provide current limiting to the individual
red LEDs 32A and green LEDs 32B respectively. Red and green LEDs
LED2 to LED2X,Y and LED3 to LED3X,Y each have at least one color
LED connected in a series and parallel configuration for redundancy.
The cathode of the last LED2X,Y of the red LEDs 32A is connected
to one side of the first switch of two-position dipswitch 54 (SW3)
with the other side of the first switch of two-position dipswitch
54 (SW3) connected to DC ground 66. Likewise, the cathode of the
last LED3X,Y of green LEDs 32B is connected to one side of the second
switch of two-position dipswitch 54 (SW4) with the other side of
the second switch of two-position dipswitch 54 (SW4) connected to
DC ground 66. When either switch on two-position dipswitch 54 (SW3
or SW4) is switched to the ON position, the cathode of the corresponding
LED2X,Y or LED3X,Y relating to the first or second switch, respectively,
will in effect be connected to DC ground 66. This completes the
respective circuit and will energize all the corresponding red LEDs
32A and/or green LEDs 32B LED arrays.
[0059] Normally open momentary power connect test switch 50A (SW2)
is provided to test and turn on optional emergency LED lights 30A
and 30B by providing temporary DC voltage power from the positive
output of bridge rectifier BR1. The DC voltage passes to LEDs 48A,
namely, LED4 to LED4X,Y by way of resistor R6. Likewise DC voltage
passes to LEDs 48B, namely, LED5 to LED5X,Y by way of resistor R7.
Resistors R6 and R7 provide current limiting to the individual LEDs
48A and 48B in optional emergency LED lights 30A and 30B. LEDs LED4
to LED4X,Y and LED5 to LED5X,Y each comprise of at least one LED
connected in a series and parallel configuration for redundancy.
The cathodes of LED 4X,Y and LED5X,Y are each connected to DC ground
66.
[0060] A fourth circuit 84 provides the automatic switching of
DC voltage power to LEDs 32A, 32B, 48A, and 48B in the event of
AC power failure. The positive terminal of battery 26 is connected
to the emitter of PNP transistor Q1. The collector of transistor
Q1 is connected to the inputs of red and green LED arrays 32A and
32B by way of diode D3 and also to the inputs of monochrome LEDs
48A and 48B in optional emergency lights 30A and 30B by way of diode
D4. Diodes D3 and D4 prevent the reverse current flow from the individual
diode arrays back through transistor Q1 into the positive terminal
of battery 26 and likewise back to the positive DC output of bridge
rectifier BR1 thus allowing current to flow only in the directions
from the anodes of diodes D3 and D4 to the cathodes of diodes D3
and D4 respectively. The base of transistor Q1 is properly biased
through resistor R3 to DC ground 66 and the cathode of diode D1
such that transistor Q1 remains off and does not conduct when DC
power is present at the positive DC output of bridge rectifier BR1.
When there is an absence of DC power at the positive DC output of
bridge rectifier BR1 as a result of AC power failure or if power
disconnect test switch 50 (SW1) is depressed, the base of transistor
Q1 will cause transistor Q1 to conduct and allow the DC voltage
from battery 26 to flow from the positive terminal of backup battery
26 through transistor Q1 from the emitter to the collector and through
diode D3 to power red LEDs 32A and green LEDs 32B, and also to flow
through diode D4 to power monochrome LEDs 48A and 48B in optional
emergency light LED lights 30A and 30B.
[0061] FIG. 6 shows a schematic block diagram 56A of a selective
bicolor LED lamp 58A taken in isolation. Selective bicolor LED lamp
58A is an alternative embodiment to selective color LED lamp 58
shown in FIG. 3. Selective bicolor LED lamp 58A can be used in retrofit
applications for existing illuminated signs or as the main selective
color LED lamp in new fixtures. LED lamp 58A includes alternating
current voltage (VAC) power input 60A that is converted by AC to
DC converter 62A, analogous to AC/DC converter 62 shown in FIG.
3 into a direct current DC voltage output. A single main or individual
current limiter, or resistor 64A, is used to limit the current going
into the bicolor LED consisting of a red and a green LED die having
separate anodes and sharing a common cathode. Bicolor red and green
LED 86 is analogous to monochrome red LEDs 32A and green LEDs 32B
of selective color sign 10.
[0062] A current limiter, or resistor, 64A, which is analogous
to current resistor 64 of LED lamp 58 is in direct current communication
with a two-position dipswitch 54A, which is analogous in operation
to dipswitch 54 discussed before and now relative to selective color
LED lamp 58A, is manually operable to close the power supply circuit.
Dipswitch 54A is in turn in direct current communication with bicolor
red and green LED 86. Current limiter 64A thus limits the current
to red and green bicolor LED 86. Bicolor LED 86 may comprise a plurality
of bicolor LEDs 86 connected in both a series and a parallel configuration
for redundancy. This is done so that the majority of red and green
bicolor LEDs 86 will remain energized in the event that one or more
bicolor LEDs 86 in each array should fail. Red colors and green
colors of bicolor LED 86 can be energized independently of one another
by dipswitch 54A. When both the red and green colors of bicolor
LED 86 are switched on and energized, a third color, namely, the
color yellow, will be produced from the color mixing of the output
color emissions of the color red with the color green. Bicolor LED
86 is connected to DC ground 66A. Dipswitch 54A comprises two operational
internal switches 54AX and 54BX. Internal switch 54AX is capable
of contact with the red color of bicolor LED 86 specifically to
the anode(s) of the LED die(s) for red colors while the cathode(s)
of the color red of LED 86 is tied directly to DC ground 66A. Internal
switch 54BX is capable of contact with the green color of bicolor
LED 86 specifically to the anode(s) of the LED die(s) for green
colors while the cathode(s) of the color green of LED 86 is tied
directly to DC ground 66A.
[0063] Selective color LED lamp 58A allows the use of a single
or multiple bicolor LEDs, that is, a single or multiple red and
green bicolor LED(s) such that the entire package of an alternative
to selective color LED sign 10 that includes separate anodes and
a common cathode can be manufactured as an alternative to the individual
and discrete red and green LEDs set forth and described herein for
selective color LED lamp 58. Thus the bicolor LED(s) 86 of FIG.
6 each contain red and green LED dies that can be selectively energized
independent of each other so as to cause the emission of the color
red or the color green, or can be energized simultaneously to emit
red color and green color to produce the color yellow.
[0064] Although the present invention has been described in some
detail by way of illustration and example for purposes of clarity
and understanding, it will, of course, be understood that various
changes and modifications may be made in the form, details, and
arrangements of the parts without departing from the scope of the
invention set forth in the following claims.
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