GB2506380A

GB2506380A - Lighting module for aircraft galley with variable brightness and colour

Info

Publication number: GB2506380A
Application number: GB1217260.7A
Authority: GB
Inventors: Arthur Jerrett; Donna Mills; Luke Poradowski
Original assignee: ALMEC EAS Ltd
Current assignee: ALMEC EAS Ltd
Priority date: 2012-09-27
Filing date: 2012-09-27
Publication date: 2014-04-02
Also published as: GB201217260D0

Abstract

An aircraft lighting module 1, particularly for use in aircraft galleys, has at least one light source, for example LEDs 3a, 3b, 3c, 3d, a controller 6, and a control panel, for example a touch sensitive surface 5a, 5b. A command from the control panel, such as a discrete command or a variable command, causes a change in the brightness level and the colour of emitted light. Also disclosed is an aircraft lighting module, particularly for use at aircraft passenger seats, where the brightness level is automatically controlled, for example according to the time of day. A data port 8 and transceiver 9 may be provided to allow the module to transmit and receive data from other modules or a separate control panel. The module may, at full brightness, emit white light at 2500 lux or more, which may reduce tiredness or jet-lag in passengers.

Description

AIRCRAFT LIGHTING MODULE

This invention relates to an aircraft lighting module.

Aircraft galleys require flexible lighting conditions. During meal service the light must be bright to allow the crew to see clearly. For example, it is important for the crew to clearly see the fill levels of hot liquids in coffee pots during filling. However, during rest periods, such as at night, the light needs to be dimmed in order to provide minimal disturbance to sleeping passengers while still offering light to those who have to move around the galley area.

Lighting for aircraft galleys typically uses incandescent lamps and/or fluorescent tubes.

Incandescent lamps are very inefficient, and generate a large amount of heat. Fluorescent tubes are more efficient, but are very limited for applications that require variable brightness.

Existing galley lighting is therefore limited in functionality.

It is desirable to alleviate some or all of the above problems.

According to a first aspect of the invention, there is provided an aircraft lighting module, comprising a light source; a controller; and a control panel, wherein the controller is adapted to vary the brightness level and the colour of light emitted from the light source in response to a command at the control panel.

The present invention provides a light source and control panel in the same module, which may be sealed and be configured to provide light at any brightness and any colour in accordance with a command at the control panel (e.g. by a crew member). For example, the lighting module may produce white light at a high level of brightness, with the relative intensity of red, green and blue being set to define a mood' of the light, e.g. a red hint can add warmth, while a blue hint can give the impression of a cooler environment. Additionally, the ability to vary the brightness of the emitted light gives the user additional flexibility, for example, when travelling at night (when many other passengers may be asleep), the user may command the module to emit very dim light to avoid disturbing the other passengers.

The light source may be a light-emitting diode. LED technology offers excellent efficiency, relatively low heat output and full control of light output intensity between fully off and fully on. LEDs are able to produce any colour of light at a brightness level sufficient to illuminate working areas such as galleys. Furthermore, LED's are significantly smaller and may be mounted on the surface of electronic circuit boards, thereby providing manufacturing cost savings. In addition, LEDs have significantly longer operating lives than either incandescent lamps or fluorescent tubes, effectively rendering them maintenance-free for the life of the interior of the aircraft.

Furthermore, the light source and control panel are provided in a single module. This allows the lighting components to be upgraded or serviced without replacing or dismantling the surrounding installation structure or decor. Therefore, maintenance time can be decreased.

Optionally, the controller is adapted to vary the brightness or the colour of the emitted light in discrete changes in response to a command at the control panel. The control panel may be a touch sensitive surface for receiving discrete inputs. Therefore, the controller may be programmed to offer the user a set number of options of brightness level or colour of the emitted light.

Alternatively, the controller is adapted to vary the brightness or the colour of the emitted light in a continuous manner in response to a command at the control panel. The control panel may be a touch sensitive surface for receiving a continuous input. Thus, the user may have more flexibility in choosing their preferred brightness level or colour of emitted light, for example, by sliding their finger across the touch sensitive surface.

Optionally, the controller is adapted to vary the brightness of the emitted light in a continuous manner in response to a command at the control panel in a first direction, and is adapted to vary the colour of the emitted light in a continuous manner in response to a command at the control panel in a second direction. Therefore, a single control panel, such as a touch sensitive surface, may produce a first signal for varying the brightness level of emitted light when it receives a command in a first direction, and may produce a second signal for varying the colour of emitted light when it receives a command in a second direction.

The lighting module may further comprise a data port for sending or receiving a data signal, wherein the controller is adapted to vary the brightness and/or colour of the emitted light in response to a data signal. Therefore, a master controller may command several lighting modules by sending a data signal to each module. In an aircraft, a member of the flight crew may therefore vary the brightness or colour of several lighting modules when required.

Moreover, the controller may be configured to produce a data signal and transmit it via the data port. Therefore, one lighting module may command another lighting module by transmitting a data signal.

According to a second aspect of the invention, there is provided a method for controlling an aircraft lighting module, comprising the steps of: receiving a first command from a user indicating a desired brightness level; receiving a second command from the user indicating a desired colour; configuring a light source to emit light at the desired colour and brightness level.

The step of configuring the light source may include the step of calculating the required pulse-width for powering the light source.

According to a third aspect of the invention, there is provided an aircraft lighting module comprising a light source; and a controller, wherein the controller is configured to automatically vary the brightness of light emitted from the light source according to the time.

In this arrangement, the aircraft lighting module may automatically vary the brightness of the light emitted such as to manipulate a user's tiredness level. This may be used to reduce the effects of jet-lag, or to make the user tired or more alert at particular times of the day.

Furthermore, the aircraft lighting module may be configured to be installed on an aircraft, wherein the aircraft lighting module includes an input for receiving flight path information of the aircraft, wherein the controller is configured to automatically vary the brightness of light emitted from the light source according to the time and the flight information. The flight information may include the number of time zones being crossed and the direction of travel.

This information may be derived from the destination and departure airports of the aircraft.

According to a fourth aspect of the invention, there is provided a method for controlling an aircraft lighting module, comprising the steps of: receiving an indication of the time; configuring a light source to emit light at a particular brightness based on the time.

Embodiments of the invention will now be described, by way of example, and with reference to the drawings in which: Figure 1 illustrates a lighting module of an embodiment of the present invention; Figure 2 illustrates several lighting modules of Figure 1, connected via power and data lines; Figure 3 illustrates several lighting modules of Figure 1 and a separate controller, connected via power and data lines; Figure 4 illustrates a method of controlling the lighting module of Figure 1; Figure 5 illustrates a lighting module of a second embodiment of the present invention; and Figure 6 illustrates a method of controlling the lighting module of the embodiment of Figure 5.

An embodiment of the present invention will now be described with reference to Figure 1. A lighting module 1 includes a first, second, third and fourth light source 3a, 3b, 3c, 3d, a first and second touch sensitive surface 5a, 5b, a controller 6, a power port 7, a data port 8, and a transceiver 9. In this embodiment, the lights sources 3a, 3b, 3c, 3d are ROB LEDs.

The first and second touch sensitive surfaces 5a, 5b are adapted to receive commands from a user by being receptive to touch (e.g. by capacitive sensing). In this embodiment, the first and second touch sensitive surfaces Sa, 5b are binary touch switches, adapted for producing a signal in response to a discrete command (e.g. being pressed once by a user).

The controller 6 is adapted to receive these signals from the first and second touch sensitive surfaces 5a, Sb. The controller 6 is further adapted to control the first, second, third or fourth light source 3a, 3b, 3c, 3d in response to receiving the signal from the first or second touch sensitive surface 5a, 5b.

The controller 6 receives electrical power via the power port 7. In this embodiment, the power input is 11 5Vac at 360-800Hz (a standard power input for aircraft technologies).

The controller 6 is adapted to supply power to each light source 3a, 3b, 3c, 3d such that the brightness of each light source 3a, 3b, 3c, 3d may be varied. This is achieved, in this embodiment, by pulse width modulation of the power applied to each light source 3a, 3b, 3c, 3d. Therefore, the pulse width may be varied in order to vary the brightness of each light source 3a, 3b, 3c, 3d.

Each light source has at least three different brightness levels, i.e. off, full brightness, and somewhere between off and full brightness (e.g. 50%). This is achieved by applying no power, full power, or pulsing full power for 50% of the time respectively. In this embodiment, the controller 6 is configured to cycle through the brightness levels in response to sequential discrete commands being received at the first touch sensitive surface Se.

For example, when the light sources 3a, 3b, 3c, 3d are off, the user may press the first touch sensitive surface 5a which sends a signal to the controller 6 to change the power supplied to the light sources 3a, 3b, 3c, 3d to pulse at full power for 50% of the time, thus producing light at 50% brightness. Then, if the user presses the first touch sensitive surface 5a again, a signal is sent to the controller 6 to change the power supplied to the light sources 3a, 3b, 3c to full power, thus producing light at 1000/c brightness.

The controller 6 is also adapted to control the colour of light emitted from each light source 3a, 3b, 3c, 3d, by controlling the brightness of red, green or blue light emitted from the light source 3a, 3b, 3c, 3d, in response to the user pressing the second touch sensitive surface Sb. In this example where the light sources 3a, 3b, 3c, 3d are RGB LEDs, such that each LED has separate red, green and blue cathodes and a common anode, the colour of the emitted light may be varied by applying pulse width modulation to the power supplied to each colour cathode.

For example, the user may have white light by applying full power to each colour cathode; or may have yellow light by applying full power to the red and green cathode but no power to the blue cathode; or may have orange light by applying full power to the red cathode, full power to the green cathode for 50% of the time, and no power to the blue cathode.

The controller 6 may be configured to cycle through different colours in response to sequential discrete commands at the touch sensitive surfaces 5b. For example, the controller 6 may cycle through a sequence of several colours (in response to the user pressing the touch sensitive surface successively), wherein white light is at the end of the sequence.

In this embodiment, the lighting module 1 includes a transceiver 9. The transceiver 9 is configured to receive data via a wireless interface (e.g. inf ía-red, radio). Therefore, a user may operate a remote control (not shown), which may have one or several touch sensitive

S

surfaces) to send signals to the controller 6 in order to control the light sources 3a, 3b, Sc, 3d. The remote control and controller 6 may be configured to use encoded signals to prevent interference from other devices.

The light module 1 of this embodiment also includes a data port 8. The data port 8 is connected to the controller 6, such that it may send/receive signals to/from other devices.

For example, as shown in Figure 2, one lighting module la may send a signal to another lighting module lb, ic, id, or may receive commands from the other lighting modules ib, ic, id. Thus, multiple lights may be controlled simultaneously by commanding a single (master) lighting module la, whose controller 6 then communicates the signals to the other lighting modules 1 b, ic, 1 d via the data port 9.

As shown in Figure 3, the lighting modules la, ib, ic may alternatively be controlled by a separate control panel 11 (rather than a master lighting module 1 a). The control panel 11 includes a first and second touch sensitive surface 15a, 15b for receiving commands from a user, a controller 16, a power port 17, and a data port 18. Therefore, the control panel 11 may receive a command from a user, and the controller 16 may communicate the resulting signal to any one or all of the lighting modules la, lb, ic in response. Therefore, on an aircraft, a member of the flight crew may have control over all of the passengers' lighting modules.

This embodiment of the invention operates in accordance with the logic shown in Figure 4.

This logic allows the lighting module to operate either as a standalone unit, or as one of a plurality of modules connected by a data bus. In this embodiment, as described above, controls are provided on the unit itself (i.e. local controls) for setting brightness and colour.

Commands may also be sent and received from remote sources via the data port.

In step 101, a user inputs a command to the second touch sensitive surface 5b (shown in Figure 1) to set the required colour of the emitted light. This defines the required proportions of red, green, blue and white to be calculated by the controller in step 102. The user is also able to set the brightness of the light output by inputting a command to the first touch sensitive surface ba in step 103. The controller then calculates the required brightness level (e.g. a setting between 0 and 100%) in step 104. Based on the colour proportions and brightness setting calculated in steps 102 and 104, the controller calculates the amount of power to be sent to each set of light sources (as FWM settings for each of the four light sources). In this embodiment of the invention, the light sources include a white LED, red LED, blue LED and green LED. Thus, in steps 106, 107, the PWM levels are transmitted to the data port and applied to the light sources in order to provide the illumination.

When the invention is used on a data bus with a number of similar devices (e.g. as depicted by Figures 2 and 3) the power settings for the light sources are transmitted on the data bus, which is connected to the data port 8 of each device. When a new command is received at the data port it is checked for integrity, for example by carrying out a Cyclic Redundancy Check (CRC) to prevent problems as a result of communication errors, as may occur as the result of electromagnetic interference. If the command received is accepted as valid as a result of the checks the new power levels are set on the light sources. In this manner the invention is able to set colour and brightness using locally mounted controls and remotely via the data port. This allows the same article to operate as a stand-alone unit, or as the recipient on a data bus (slave device) or as the source of commands on a data bus (bus master device).

A second embodiment of the invention will now be described with reference to Figures 5 and 6. In this embodiment, the light module 11 (which has the same components as the lighting module 1 in the above embodiment) is installed in an aircraft passenger seat and is configured such that the light sources 13a, 13b, 13c, 13d are directed towards a user's face.

In such an arrangement, sufficiently bright light may be applied to the user's eyes for suppression of the chemical Melatonin in the user, whilst using a relatively low-power light.

Also, this arrangement reduces nuisance light pollution to occupants of nearby seats.

In a further enhancement, the light module 11 is configured such that the light sources 1 3a, 1 3b, 1 Sc, 1 3d are positioned in front of the user, offset to one side or above a normal direction of the user's gaze.

In this embodiment, the light sources 13a, 13b, 13c, 13d emit white light (i.e. 400nm-760nm light) with a brightness of 2,500 Lux or more. This is significantly brighter than prior art aircraft passenger seat lights, and has the benefit of suppressing the development of Melatonin in the user. Thus, by controlling the brightness levels of the lighting module 11, the user's tiredness levels may be influenced. Such light therapy" may therefore be used to combat jot-lag.

As shown in Figure 5, the controller 16 of the lighting module 11 of this embodiment is also able to adjust the light settings (colour and/or brightness) automatically (i.e. without being actively controlled by the user). Thus, the controller 16 may cause the light sources 1 3a, 1 3b, 1 3c, 1 3d to emit light of a particular brightness and colour based on a predetermined illumination cycle.

For example, in order to reduce the effects of jet-lag, the user's face may be illuminated with bright light during certain time periods, and the light levels may be dimmed during other time periods. This manipulates the levels of Melatonin in the user and therefore the user's tiredness levels.

The optimum timing for illuminating the user's face is dependent upon the number of time zones being crossed and the direction of travel (east-to-west or vice-versa). In this embodiment, shown in FigureS, the controller 16 receives information from the data port 16 relating to the particular flight. For example, the controller 16 may receive information on the direction of travel, the time zones being crossed and the current time. The controller 16 may use this information to calculate an automated illumination cycle in order to minimize jet-lag.

The user may turn the automated cycle on or off by operating a switch. This reverts the lighting module 11 back to normal operation (as described in the above embodiment), in which the user determines the brightness and colour levels of the lights sources 1 3a, 1 3b, 13c, 13d.

Jet lag reduction works by exposing the user to bright light at certain times of day, and avoiding light at other times. The timing of the exposure and avoidance periods varies depending on the journey being made, although the duration of the exposure period is usually in the region of 3 hours. Normally it is beneficial to expose the passenger to bright light in the morning if travelling east, or in the evening if travelling west. The automated cycle provided by the invention would turn the light on at the time and for the duration calculated by its programmed jet lag calculation algorithm.

The algorithm that is used to calculate the start time and duration of illumination can be programmed to suit. The algorithm described below provides one possible means of calculating the lighting regime.

The automated cycle receives information from the central aircraft system, including the current time at the flight's origin (T0), and the current time at the flight's destination (Ti).

From this information the algorithm is able to calculate the number of time zones being crossed and the direction of travel. The number of time zones crossed can be calculated by the equation T -T0 = N; if this result is negative then the passenger is travelling west, if positive then the journey is to the east. In this embodiment, the algorithm only performs the automated lighting cycle if the number of time zones crossed is greater or equal to four.

The algorithm calculates the time (relative to destination time) that the light will switch on using (as an example) the following algorithm. The skilled reader will understand that it may be necessary to calculate the destination time from Universal Time (GMT) according to the data that is supplied via the data port from the aircraft systems.

* If N is -12 to -4, then the light exposure start time T3 will begin at T = 26 + * If N7 is +3 to +12 then the light exposure start time T will begin at T = 2 + N7.

For example, if a journey is made from London to New York then N7 = -5 and light exposure would start at 26 -5 = 21:00 (09:OOpm) New York Time. Alternatively, if travelling from Los Angeles to London then ft = +8 and the light exposure time would start at 2 +8 = 10:00am London Time. The skilled reader will understand that, in the extreme case of traversing 12 time zones the algorithm gives the same start time whether the journey is made in an easterly or westerly direction.

The invention can be programmed to start and finish the light application instantly, or by way of a gradual lade in or out depending on the requirements of the customer. The programming can also define which functions of the invention have priority -for example the the user input may over-ride a conflicting command from the automated cycle function.

The lighting module 11 can also be used to simulate dawn/dusk to the user. That is, at a particular time of day, the lighting module 11 may initiate a gradual dimming of the light level emitted from the light sources 13a, 13b, 13c, 13d over a period of time. This simulates dusk and has the effect of making the user drowsy. At another time of day, the lighting module 11 may simulate dawn by gradually increasing the light levels over a period of time (e.g. 15 minutes to 2 hours). For example, this could be initiated two hours before landing, or at dawn for destination time. This has the effect of triggering the release of Cortisol in the user as part of the user's wake-up cycle so the user wakes up feeling better rested and more alert.

The activation of these cycles need not be automated. For example the user may preset an alarm feature such that dawn is simulated at a chosen time. As the light sources 1 3a, 1 3b, 1 3c, 1 3d are directed towards a particular user's face, it has a limited effect on occupants of nearby seats. In addition, the user may select a bright light on demand, such that they remain alert. This enables the user to focus (e.g. on work) during a long flight.

In the third embodiment, the user's face is illuminated with predominantly white light (400- 7SOnm). However, blue or green light (430-500nm) is also effective.

In the embodiments described above, the touch sensitive surfaces are binary touch switches configured to produce a signal due to a discrete command (e.g. being pressed by the user).

As described above, the first touch sensitive surface is configured to vary the brightness of the light sources, and the second touch sensitive surface is configured to vary the colour of the light sources. However, the skilled person will realise that the present invention is not limited to this configuration. That is, the first touch sensitive surface may be used to turn the light on or off, and the second touch sensitive surface may be used to cycle through the different brightness and colour options.

The touch sensitive surfaces may include a graphic to indicate its function to the user.

The skilled person will also understand that the touch sensitive surfaces are not limited to the binary touch switch described above. For example, the touch sensitive surface may be a linear touch bar, which is configured to receive a command from a user in a linear, continuous manner (i.e. producing a variable signal, from O% to 10O%). Therefore, the controller is configured to vary the brightness and/or colour in response to these commands (e.g. the brightness and/or colour may be varied in proportion to the received signal).

The skilled person will understand that the touch bar does not need to be linear. Rather, the touch bar may be configured to receive commands in a circular fashion, for producing a variable signal.

Moreover, the touch sensitive surfaces may be 2D touch sensitive areas, configured to receive a command from a user in a linear, continuous manner in a first direction, and to receive a command from a user in a linear, continuous manner in a second direction (which may be perpendicular to the first). Therefore, the touch sensitive areas may be configured to produce a variable signal for brightness, from 0% to 100%, as the user inputs a command in the first direction, and may produce a variable signal for colour, from 0% to 100%, as the user inputs a command in the second direction (such that only one touch sensitive surface is required). The controller may then receive the signals for brightness and colour from the touch sensitive surfaces and drive the light sources accordingly.

The skilled person will also understand that the light sources of the present invention are not limited to RGB LEDs. That is, RGB LEDs are preferable, as the controller may control the brightness and/or colour of the emitted light. However, where the lighting module is only configured to vary the brightness (and not the colour) of emitted light, single colour LEDs may be used. Furthermore, the light sources do not need to be LEDs. Rather, any suitable light source (e.g. compact fluorescent bulbs) may be used.

Additionally, the skilled person will understand that the present invention is not limited to having four light sources. Rather, the present invention may have one or several light sources.

The skilled person will also understand that the present invention is not limited to using pulse width modulation to vary the brightness of the light sources. Rather, any suitable method may be used, which may depend on the particular light source used (e.g. a potentiometer may be used to vary the brightness of an incandescent bulb).

In the above embodiments, the controller and data port are configured to use the data protocol RS232. However, the skilled person will understand that any suitable data protocol may be used (e.g. RS4BS, CANBUS etc), and may be selected according to the particular application. In addition, the skilled person will understand that it is not essential that the transceiver be adapted to receive wireless signals. Rather, the transceiver may have a wired connection to a remote control.

The skilled person will also understand that the power input recited above is not essential, and the lighting module of the present invention may be adapted to use any suitable power input. For example, the power input may be 28Vdc.

In the arrangement shown in Figure 2 (wherein there are multiple lighting modules), the skilled person will understand that it is only necessary for one unit to include a control panel (thus, the control panels on the other lighting modules may be omitted). It is also possible for the control panel of each lighting module to control the light source on every other lighting module.

In the arrangement shown in Figure 3 (wherein multiple lighting modules are controlled by a separate control panel), the skilled person will understand that the lighting modules need not have control panels.

The skilled person will understand that any combination of features is possible without departing from the scope of the invention, as claimed.

Claims

CLAIMS1. An aircraft lighting module, comprising a light source; a controller; and a control panel, wherein the controller is adapted to vary the brightness level and the colour of light emitted from of the light source in response to a command at the control panel.
2. An aircraft lighting module as claimed in Claim 1, wherein the light source is a light emitting diode.
3. An aircraft lighting module as claimed in Claim 1 or Claim 2, wherein the controller is adapted to vary the brightness level of the light source in discrete changes in response to a command at the control panel.
4. An aircraft lighting module as claimed in any one of the preceding claims, wherein the controller is adapted to vary the colour of the emitted light in discrete changes in response to a command at the control panel.
5. An aircraft lighting module as claimed in any one of the preceding claims, wherein the control panel is a touch sensitive surface for receiving discrete inputs.
6. An aircraft lighting module as claimed in Claim 1 or Claim 2, wherein the controller is adapted to vary the brightness of the emitted light in a continuous manner in response to a command at the control panel.
7. An aircraft lighting module as claimed in either Claim 1, Claim 2 or Claim 6, wherein the controller is adapted to vary the colour of light emitted from the light source in a continuous manner in response to a command at the control panel.
8. An aircraft lighting module as claimed in Claim 1 or Claim 2, wherein the controller is adapted to vary the brightness of the emitted light in a continuous manner in response to a command at the control panel in a first direction, and is adapted to vary the colour of the emitted light in a continuous manner in response to a command at the control panel in a second direction.
9. An aircraft lighting module as claimed in any one of Claims 1, Claim 6, Claim 7 or Claim 8, wherein the control panel is a touch sensitive surface for receiving a continuous input.
10. An aircraft lighting module as claimed in any preceding claim, further comprising a data port for receiving a data signal, wherein the controller is adapted to vary the brightness and/or colour of the emitted light in response to a data signal.
11. An aircraft lighting module as claimed in Claim 10, wherein the controller is configured to produce a data signal and transmit it via the data port.
12. An aircraft lighting module as claimed in any preceding claim, wherein a brightness of the light source is at least 25001ux.
13. An aircraft lighting module comprising a light source; and a controller, wherein the controller is configured to automatically vary the brightness of light emitted from the light source according to the time.
14. An aircraft lighting module as claimed in Claim 13, configured to be installed on an aircraft and further comprising an input for receiving flight information of the aircraft, wherein the controller is configured to automatically vary the brightness of light emitted from the light source according to the time and flight information.
15. An aircraft lighting module as claimed in Claim 14, wherein the flight information includes the number of time zones being crossed and the direction of travel.
16. An aircraft lighting module as claimed in any one of Claims 13 to 15, wherein the brightness of the light source is at least 25001ux.
17. An aircraft lighting module substantially as herein described with reference to and as shown in the accompanying drawings.
18. A method for controlling an aircraft lighting module, comprising the steps of: receiving a first command from a user indicating a desired brightness level; receiving a second command from the user indicating a desired colour; configuring a light source to emit light at the desired colour and brightness level.
19. A method as claimed in Claim 18, wherein the step of configuring the light source includes the step of calculating the required pulse-width for powering the light source.
20. A method for controlling an aircraft lighting module, comprising the steps of: receiving an indication of the time; and configuring a light source to emit light at a particular brightness based on the time.
21. A method as claimed in Claim 20, wherein the aircraft lighting module is configured to be installed on an aircraft, the method further comprising the steps of: receiving flight information of the aircraft; configuring the light source to emit light at a particular brightness based on the time and the flight information.
22. A method as claimed in Claim 21, wherein the flight information includes the number of time zones being crossed and the direction of travel.
23. A method substantially as herein described with reference to and as shown in the accompanying drawings.