Note: Descriptions are shown in the official language in which they were submitted.
CA 02943535 2016-09-27
HYBRID EMERGENCY LIGHTING SYSTEM
BACKGROUND
Field of the Invention
The present application relates to lighting systems. In particular, the
present application
s relates to rechargeable emergency lighting systems for vehicles,
including, but not
limited to, aircraft.
Description of Related Art
Some aircraft comprise emergency lighting systems for use when a power supply
to a
primary lighting system is interrupted. In some cases, the emergency lighting
systems
comprise rechargeable batteries and/or light emitting diodes. In some cases,
the
rechargeable batteries of the emergency lighting systems prematurely fail or
perform
poorly as a result of recharging and discharging the batteries in accordance
with field
conditions that are undesirable for maintenance and/or performance of the
batteries.
There are many known ways to provide emergency lighting systems, however,
considerable shortcomings remain.
SUMMARY
In one aspect, there is provided an emergency lighting system (ELS) for an
aircraft,
comprising: a capacitor; a light emitting diode (LED) selectively powered by
the
capacitor; and at least one of a photoluminescent sign and a photoluminescent
panel
configured to receive light emitted from the LED.
In another aspect, there is provided a method of providing lighting,
comprising:
providing a capacitor; charging the capacitor; providing a light emitting
diode (LED);
powering the LED using the capacitor and causing the LED to emit light and
cast the
emitted light onto at least one of a photoluminescent sign and a
photoluminescent
panel; reducing an amount of light emitted from the LED; and radiating light
from at
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least one of the photoluminescent sign and the photoluminescent panel after
the
reduction in amount of light emitted from the LED.
In a further aspect, there is provided an aircraft, comprising: onboard power
supply; and
an emergency lighting system (ELS), comprising: a capacitor; a light emitting
diode
S (LED) selectively powered by the capacitor; and at least one of a
photoluminescent sign
and a photoluminescent panel configured to receive light emitted from the LED.
DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the application are set forth in
the
appended claims. However, the application itself, as well as a preferred mode
of use,
and further objectives and advantages thereof, will best be understood by
reference to
the following detailed description when read in conjunction with the
accompanying
drawings, wherein:
Figure 1 is an orthogonal schematic side view of a helicopter according to the
present
application.
Figure 2 is a schematic of an emergency lighting system of the helicopter of
Figure 1.
Figure 3A is a simplified view of the emergency lighting system of Figure 2 in
operation
with external power provided.
Figure 3B is a simplified view of the emergency lighting system of Figure 2 in
operation
with external power removed and internal power being utilized.
Figure 3C is a simplified view of the emergency lighting system of Figure 2 in
operation
with external power removed and without utilization of internal power.
Figure 4 is a flowchart of a method of operating the emergency lighting system
of Figure
2.
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Figure 5A is a simplified view of an alternative embodiment of an emergency
lighting in
operation with external power provided.
Figure 5B is a simplified view of the emergency lighting system of Figure 5A
in
operation with external power removed and internal power being utilized.
Figure 5C is a simplified view of the emergency lighting system of Figure 5A
in
operation with external power removed and without utilization of internal
power.
Figure 6 is a flowchart of a method of operating the emergency lighting system
of
Figure 5A.
Figure 7 is a chart showing the visibility of a photoluminescent panel of the
emergency
lighting system of Figure 5A over a period of time.
Figure 8A is a simplified view of an alternative embodiment of an emergency
lighting in
operation with external power provided.
Figure 8B is a simplified view of the emergency lighting system of Figure 8A
in
operation with external power removed and internal power being utilized.
Figure 8C is a simplified view of the emergency lighting system of Figure 8A
in
operation with external power removed and without utilization of internal
power.
Figure 9 is a flowchart of a method of operating the emergency lighting system
of Figure
8A.
While the system and method of the present application is susceptible to
various
modifications and alternative forms, specific embodiments thereof have been
shown by
way of example in the drawings and are herein described in detail. It should
be
understood, however, that the description herein of specific embodiments is
not
intended to limit the application to the particular embodiment disclosed, but
on the
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contrary, the intention is to cover all modifications, equivalents, and
alternatives falling
within the scope of the process of the present application as defined by the
appended
claims.
DETAILED DESCRIPTION
Illustrative embodiments of the preferred embodiment are described below. In
the
interest of clarity, not all features of an actual implementation are
described in this
specification. It will of course be appreciated that in the development of any
such actual
embodiment, numerous implementation-specific decisions must be made to achieve
the
developer's specific goals, such as compliance with system-related and
business-
related constraints, which will vary from one implementation to another.
Moreover, it will
be appreciated that such a development effort might be complex and time-
consuming
but would nevertheless be a routine undertaking for those of ordinary skill in
the art
having the benefit of this disclosure.
In the specification, reference may be made to the spatial relationships
between various
components and to the spatial orientation of various aspects of components as
the
devices are depicted in the attached drawings. However, as will be recognized
by those
skilled in the art after a complete reading of the present application, the
devices,
members, apparatuses, etc. described herein may be positioned in any desired
orientation. Thus, the use of terms to describe a spatial relationship between
various
components or to describe the spatial orientation of aspects of such
components should
be understood to describe a relative relationship between the components or a
spatial
orientation of aspects of such components, respectively, as the device
described herein
may be oriented in any desired direction.
Referring to Figure 1 in the drawings, a helicopter 100 according to the
present
disclosure is shown. The helicopter 100 generally comprises a fuselage 102, a
tail boom
104, an engine 106, a main rotor drive system 108, and a tail rotor drive
system 110.
The main rotor drive system 108 is coupled to the engine 106 to drive a
primary rotor
mast 112. The tail rotor drive system 110 is coupled to the engine 106 to
drive a tail
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rotor mast 114. The helicopter 100 further comprises an emergency lighting
system 200
configured to selectively emit light within and/or on the helicopter 100. In
some cases,
the emergency lighting system 200 is provided electrical power from an onboard
power
system 116 that can be driven by the engine 106. In some cases, the emergency
lighting system 200 is provided electrical power from a ground power unit 118
that can
be connected to the electrical systems of the helicopter 100 to supply
electrical energy
to the helicopter 100 when the helicopter is grounded.
Referring now to Figure 2, a schematic diagram of the electrical components of
the
emergency lighting system (ELS) 200 is shown. Most generally, the ELS 200 is
configured to receive direct current voltage of about 28 volts. In some
embodiments, the
ELS 200 comprises a ground connection 202 and a positive connection 204 which
are
selectively connected to external power sources, such as, but not limited to,
the
onboard power system 116 and the ground power unit 118. In some embodiments,
the
ELS 200 is generally configured to selectively charge a capacitor or
supercapacitor 206.
A transistor, 208 is used to switch between providing electrical charge to the
supercapacitor 206 and not providing electrical charge to the supercapacitor
206. The
transistor 208 comprises an NPN type transistor comprising a collector 210, an
emitter
212, and a base 214. When a charge is applied to the base 214 that is
relatively more
positive than a charge applied to the emitter 212, the transistor 208 is
opened and
allows electrical energy to flow from each of the collector 210 and base 214
to the
emitter 212. The ELS 200 further comprises resistors 216 and 218, each
configured as
100 ohm resistors with a current rating of 2 watts, which regulate a rate at
which
electrical energy is supplied to collector 210 when the transistor 208 is
open. The
transistor 208 may comprise a so-called 2N2222 transistor which is a
commercially
available NPN bipolar junction transistor suitable for use in switching
applications.
The supercapacitor 206 is connected between the emitter 212 and the ground
connection 202. Accordingly, when the transistor 208 is open, electrical
energy flows
through the transistor 208 to the supercapacitor 206. Depending on the charge
state of
the supercapacitor 206, the supercapacitor 206 can receive and store
electrical energy
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provided from the transistor 208. Because the resistors 216 and 218 are
disposed in
series with the collector 210, the rate at which energy is provided to the
supercapacitor
206 through the transistor 208 is determined as a function of the sum of the
resistance
of the resistors 216 and 218. The supercapacitor 206 comprises an electrical
energy
storage capacity of 2.2 Fared at 5.5 volts. As shown, the ELS 200 is
configured to
supply between about 0 to about 133 milliamps of current through the
transistor 208.
The ELS 200 further comprises light emitting diodes (LEDs) 220 and 222, each
being
rated for 18 milliamps of current. In this embodiment, the LEDs 220 and 222
are
considered bright white LEDs. As shown, electrical energy is switched between
being
provided to the LEDs 220 and 220 and not provided to the LEDs 220, 222 by a
transistor 224. The transistor 224 comprises a PNP type transistor comprising
a
collector 226, an emitter 228, and a base 230. When a charge is applied to the
emitter
228 that is relatively more positive than a charge applied to the base 230,
the transistor
224 is opened and allows electrical energy to flow from the collector 226 to
the emitter
228. The transistor 224 may comprise a so-called 2N2907 transistor which is a
commercially available PNP bipolar junction transistor suitable for use in
switching
applications.
The ELS 200 further comprises a multi-position switch 232 configured to
control the
behavior of the ELS 200. The switch 232 comprises a common node 234, an Auto
node
236, an On node 238, and an Off node 240. Most generally, when the switch 232
is
configured to electrically connect the common node 234 and the Off node 240,
the
LEDs 220, 222 are not provided with power, regardless of the state of whether
external
power is supplied to the ELS 200 and regardless of whether the supercapacitor
206 is
sufficiently charged to power the LEDs 220, 222. Operation of the ELS 200 can
be
utilized during night operations in which it may be desirable for the
helicopter 100 to
remain dark, such as, but not limited to, situations in which night vision
goggles are
utilized by occupants of the helicopter 100. When the switch 232 is configured
to
electrically connect the common node 234 and the On node 238, the LEDs 220,
222 are
provided with power from at least one of external power supplied to the ELS
200 and
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the supercapacitor 206. When the switch is configured to electrically connect
the
common node 234 and the Auto node 236, the LEDs 220, 222 are not supplied
power
when external power is supplied to the ELS 200 but the LEDs 220, 222 are
supplied
power from the supercapacitor 206 when the external power is not supplied to
the ELS
200. The ELS 200 can further comprise a sign or panel 242 configured and/or
disposed
relative to the LEDs 220, 222 to be exposed to the photons or light energy
emitted by
the LEDs 220, 222.
Referring now to Figures 3A-3B, example progressive operation of the ELS 200
is
shown schematically. Figure 3A shows operation of the ELS 200 with the switch
232 set
to connect the On node 238 to the common node 234. While external power is
supplied
to the ELS 200, both ambient light from other lighting systems and light from
the LEDs
220, 222 are cast onto a sign or panel 242. Accordingly, light is reflected
from the panel
242 and the panel 242 is visible. Figure 3B shows operation of the ELS 200
with the
switch 232 continuing to connect the On node 238 to the common node 234, but
no
external power supplied to the ELS 200. Without the other primary lighting
systems
providing ambient light, the majority of light cast onto the sign or panel 242
is light
emitted from the now supercapacitor powered LEDs 220, 222. Accordingly, the
light
reflected from the sign or panel 242 is primarily resultant from the operation
of the LEDs
220, 222. Figure 3C shows an operational state of the ELS 200 when both the
external
power is not provided to the ELS 200 and the supercapacitor of the ELS 200 has
expended stored energy to a point that LEDs 220, 222 cannot be powered.
Because the
LEDs 220, 222 are not powered and there is no other primary lighting system
operating,
little or no light is cast onto the sign or panel 242 and the sign or panel
242 reflects no
appreciable light and is therefore not visible or barely visible.
Referring now to Figure 4, a flowchart of a method 400 of operating the ELS
200 is
shown. The method 400 may begin at block 402 where external aircraft power,
such as,
but not limited to, power from an onboard power system 116 or ground power
unit 118,
is provided to the ELS 200. The method 400 may continue at block 404 where a
capacitor, such as, but not limited to, a supercapacitor 206 is charged by the
power
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supplied from the external aircraft power. The method 400 may continue at
block 406
where the external aircraft power is removed, such as, but not limited to, due
to an
emergency related to failure of an onboard power system 116 and/or a temporary
lack
of external power due to disconnection and/or failure of a ground power unit
118. The
method 400 may continue at block 408 where as a function of the switch 232
being set
to connect the common node 234 to either the On node 238 or the Auto node 236,
power is provided from the supercapacitor 206 to an LED of the ELS 200. The
method
400 may continue at block 410 where the LED that is powered by the
supercapacitor
206 emits light and the light is cast onto a sign or panel 242, thereby making
the sign or
panel 242 visible in spite of the lack of external power.
Referring now to Figures 5A-5B, example progressive operation of an ELS 500 is
shown schematically. ELS 500 is substantially similar to ELS 200 but further
comprises
a photoluminescent sign or panel 244 rather than a non-photoluminescent sign
or panel
such as sign or panel 242. Figure 5A shows operation of the ELS 500 with the
switch
232 set to connect the On node 238 to the common node 234 and with the
photoluminescent sign or panel 244 in an initial uncharged state in which the
panel 244
does not radiate photons or light energy. While external power is supplied to
the ELS
500, both ambient light from other lighting systems and light from the LEDs
220, 222 are
cast onto the photoluminescent sign or panel 244. Accordingly, light is
reflected from the
panel 244 and the panel 244 is visible. Figure 5B shows operation of the ELS
500 with
the switch 232 continuing to connect the On node 238 to the common node 234,
but no
external power supplied to the ELS 500. Without the other primary lighting
systems
providing ambient light, the majority of light cast onto the sign or panel 244
is light
emitted from the now supercapacitor powered LEDs 220, 222. Accordingly, the
light
reflected from the sign or panel 244 is primarily resultant from the operation
of the LEDs
220, 222. However, unlike operation of ELS 200, since the photoluminescent
panel 244
has received and stored light energy in the previous operational state of
Figure 5A, in
addition to the light being reflected from the panel 244 the panel 244 emits
and/or
radiates photons, light, and/or light energy as a function of the panel 244
discharging.
Figure 5C shows an operational state of the ELS 500 when both the external
power is
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not provided to the ELS 500 and the supercapacitor of the ELS 500 has expended
stored energy to a point that LEDs 220, 222 cannot be powered. Because the
LEDs
220, 222 are not powered and there is no other primary lighting system
operating, little
or no light is cast onto the sign or panel 244 and the sign or panel 244
reflects no
s appreciable light. However, unlike operation of ELS 200, the panel 244
can nonetheless
continue to emit and/or radiate photons, light, and/or light energy and
therefore remain
visible during the discharge of the panel 244.
Referring now to Figure 6, a flowchart of a method 600 of operating the ELS
500 is
shown. The method 600 may begin at block 602 where external aircraft power,
such as,
but not limited to, power from an onboard power system 116 or ground power
unit 118,
is provided to the ELS 500. The method 600 may continue at block 604 where a
capacitor, such as, but not limited to, a supercapacitor 206 is charged by the
power
supplied from the external aircraft power. The method 600 may continue at
block 606
where the external aircraft power is removed, such as, but not limited to, due
to an
emergency related to failure of an onboard power system 116 and/or a temporary
lack
of external power due to disconnection and/or failure of a ground power unit
118. The
method 600 may continue at block 608 where as a function of the switch 232
being set
to connect the common node 234 to either the On node 238 or the Auto node 236,
power is provided from the supercapacitor 206 to an LED of the ELS 500 and the
LED
that is powered by the supercapacitor 206 emits light and/or casts light onto
a
photoluminescent sign or panel 244, thereby making the sign or panel 244
visible in
spite of the lack of external power while also charging the photoluminescent
sign or
panel 244. The method 600 may continue at block 610 where emission of light
from the
LED is discontinued and the panel 244 continues to emit or radiate light,
photons,
and/or light energy. Accordingly, the panel 244 can remain visible during the
discharging of the panel 244.
Referring now to Figure 7, a chart 700 displays the interplay between
visibility of a
photoluminescent sign or panel, such as panel 244, as a function of being
primarily lit by
the supercapacitor powered LEDs and thereafter being primarily visible by
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photoluminescence of the panel 244 itself. The chart 700 comprises a first
curve 702
which represents the measured intensity of illumination of the panel 244 over
time
during which illumination of the panel 244 is primarily visible as a function
of operation
of the supercapacitor powered LEDs. The chart 700 further comprises a second
curve
s 704 which represents the intensity of light discharged from the panel 244
as a function
of the photoluminescent discharge of the panel 244. It is shown that during
the
operation of the LEDs, a period lasting about 25 minutes, the photoluminescent
charge
of the panel 244 generally increases for about the first 15 minutes. After
about 15
minutes, the intensity of the LEDs powered by the supercapacitor is not
sufficient to
further charge the panel 244 and the panel 244 begins to discharge. After
about 20
minutes of operation, the illumination of the panel 244 is beginning to be
significantly
more attributable to the photoluminescent discharge of the panel 244 and
eventually the
illumination is fully attributable to the discharge of the panel 244. In this
embodiment,
the panel 244 remains visibly discernable after 30 minutes of operation even
though the
LEDs have discontinued contributing to the illumination of the panel 244.
Referring now to Figures 8A-8B, example progressive operation of an ELS 800 is
shown schematically. ELS 800 is substantially similar to ELS 500 but further
comprises
an edge light diffuser 246. The edge light diffuser 246 is disposed relative
to each of the
LEDs 220, 222 and the photoluminescent panel 244 so that although the panel
244 is
not primarily located within a primary emission pattern of the LEDs 220, 222,
the light
emitted from the LEDs 220, 222 is received by the diffuser 246 and redirected
onto the
panel 244. Accordingly, the addition of the edge light diffuser 246 can allow
alternative
physical packaging configurations of the ELS 800 wherein panel 244 (or panel
242) can
be illuminated by the LEDs 220, 222 despite being located outside a typical
radiation
pattern of the LEDs 220, 222. Figure 8A shows operation of the ELS 800 with
the switch
232 set to connect the On node 238 to the common node 234 and with the
photoluminescent sign or panel 244 in an initial uncharged state in which the
panel 244
does not radiate photons or light energy. While external power is supplied to
the ELS
800, both ambient light from other lighting systems and light from the LEDs
220, 222 are
cast onto the photoluminescent sign or panel 244. The light from the LEDs 220,
222 is
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routed to the panel 244 through the edge light diffuser 246. Accordingly,
light is reflected
from the panel 244 and the panel 244 is visible. Figure 8B shows operation of
the ELS
800 with the switch 232 continuing to connect the On node 238 to the common
node
234, but no external power supplied to the ELS 800. Without the other primary
lighting
systems providing ambient light, the majority of light cast onto the sign or
panel 244 is
light emitted from the now supercapacitor powered LEDs 220, 222 and through
the
diffuser 246. Accordingly, the light reflected from the sign or panel 244 is
primarily
resultant from the operation of the LEDs 220, 222 and optical redirection
provided by
the diffuser 246. However, unlike operation of ELS 200, since the
photoluminescent
panel 244 has received and stored light energy in the previous operational
state of
Figure 8A, in addition to the light being reflected from the panel 244, the
panel 244
emits and/or radiates photons, light, and/or light energy as a function of the
panel 244
discharging. Figure 8C shows an operational state of the ELS 800 when both the
external power is not provided to the ELS 800 and the supercapacitor of the
ELS 800
has expended stored energy to a point that LEDs 220, 222 cannot be powered.
Because the LEDs 220, 222 are not powered and there is no other primary
lighting
system operating, little or no light is cast onto the sign or panel 244 and
the sign or
panel 244 reflects no appreciable light. However, unlike operation of ELS 200,
the panel
244 can nonetheless continue to emit and/or radiate photons, light, and/or
light energy
and therefore remain visible during the discharge of the panel 244.
Referring now to Figure 9, a flowchart of a method 900 of operating the ELS
800 is
shown. The method 900 may begin at block 902 where external aircraft power,
such as,
but not limited to, power from an onboard power system 116 or ground power
unit 118,
is provided to the ELS 800. The method 900 may continue at block 904 where a
capacitor, such as, but not limited to, a supercapacitor 206 is charged by the
power
supplied from the external aircraft power. The method 900 may continue at
block 906
where the external aircraft power is removed, such as, but not limited to, due
to an
emergency related to failure of an onboard power system 116 and/or a temporary
lack
of external power due to disconnection and/or failure of a ground power unit
118. The
method 900 may continue at block 908 where as a function of the switch 232
being set
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to connect the common node 234 to either the On node 238 or the Auto node 236,
power is provided from the supercapacitor 206 onto an edge light diffuser,
such as edge
light diffuser 246. The method 900 may continue at block 910 where light is
transmitted
through the edge light diffuser and from the edge light diffuser onto a
photoluminescent
sign or panel, such as panel 244, thereby making the sign or panel 244 visible
in spite
of the lack of external power while also charging the photoluminescent sign or
panel
244. The method 900 may continue at block 912 where emission of light from the
LED
is discontinued and the panel 244 continues to emit or radiate light, photons,
and/or light
energy. Accordingly, the panel 244 can remain visible during the discharging
of the
io panel 244.
In alternative embodiments, the values and/or ratings of electrical components
of ELS
200, 500, 800 can be varied to provide different rates of supercapacitor 206
charging
and discharging and/or LED 220, 220 intensity. Further, because performance of
a
photoluminescent sign or panel such as panel 244 is dependent upon the
chemical
is makeup of the photoluminescent material and the amount of
photoluminescent material
utilized, alternative embodiments can provide photoluminescent discharge for
different
durations of time as well as different photoluminescent discharge intensities.
In some
embodiments, the signs or panels can be disposed within a cabin and/or cockpit
of an
aircraft. In some embodiments, an ELS 200, 500, 800 may additionally and/or
20 alternatively provide ambient lighting to a cabin and/or cockpit of an
aircraft. In some
embodiments, at least one of an onboard power system 116 and a ground power
unit
118 can comprise a portion of the ELS 200, 500, 800.
The particular embodiments disclosed above are illustrative only, as the
application may
be modified and practiced in different but equivalent manners apparent to
those skilled
25 in the art having the benefit of the teachings herein. It is therefore
evident that the
particular embodiments disclosed above may be altered or modified, and all
such
variations are considered within the scope of the application. Accordingly,
the
protection sought herein is as set forth in the description. It is apparent
that an
application with significant advantages has been described and illustrated.
Although the
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present application is shown in a limited number of forms, it is not limited
to just these
forms, but is amenable to various changes and modifications.
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