GB2578870A

GB2578870A - Method of modifying a lighting system in an aircraft

Info

Publication number: GB2578870A
Application number: GB1818267.5A
Authority: GB
Inventors: Alan Rust Daniel
Original assignee: Cobalt Aerospace Ltd
Current assignee: Cobalt Aerospace Ltd
Priority date: 2018-11-09
Filing date: 2018-11-09
Publication date: 2020-06-03
Also published as: GB201818267D0

Abstract

A lighting system for an aircraft has one or more light modules 22 and can be controlled to select different light settings (fig.1,12,14,16,18), such as dim and bright. The control 10 can be placed into a data transmission mode by selecting a certain sequence of settings, which may act as an initialization procedure to prevent accidental use. The control can then generate a stream of data signals 34 carrying programming information, such as pre-set scene information, transmitting them to reconfigure the light output of the light modules. The data signals may be encoded using a coding scheme such as Manchester encoding and generated at a very low data rate in the range of 0.5-2 bits per second to achieve a robust data transfer over a control line 32 between the control and a memory 28 of the light modules, used to store the pre-set scenes. The control may be a rotary switch, keypad or touchscreen.

Description

Title: Method of modifying a lighting system in an aircraft

Field of the invention

This invention relates to a method of modifying a lighting system in an aircraft and an associated lighting system.

Background

LED lighting as a drop-in replacement for existing fluorescent based cabin lighting systems on aircraft has become common place, as have replacement lighting systems offering a lot more features than the original equipment (full mood systems'), albeit requiring too many changes to be considered 'drop in'.

A branch of drop-in lighting has emerged which provides some of the features of more advanced systems without the need for aircraft changes. Typically, these Is systems hold in on-board memory the brightness and colour settings for each mode of operation such as Bright, Medium and Dim, and when one of these modes is activated by cabin crew from a central control means or button, the light units display the preset colour and brightness.

A typical aircraft will have around 40 to MO lighting units that illuminate the ceiling of the aircraft and about the same quantity to illuminate the sidewalls of the aircraft cabin. These lighting units are controlled in blocs from central control switches or touch screens, with those blocks often being assigned to aircraft cabin zones such as Business class or Economy class.

When an airline upgrades to a 'drop in' mood lighting system which has preprogrammed colours and light levels, a great deal of time is spent choosing the correct lighting scheme of colours and brightness levels for each zone and within that zone for the ceiling and sidewall lights to create 'scenes' that support the airline's branding, or promote sleep or make the meal service look better, for example.

Once the lighting system is deployed, if there is a need to change these pre-set scenes, a large amount of work can be involved in doing so.

There are some solutions that exist to overcome this, involving connecting either via a wired or wireless link to each lighting unit in turn and transferring new settings to the lighting unit. This can be a process that takes considerable time to accomplish considering the quantity of lighting units on a typical aircraft. Outside of an aircraft environment, a simple solution would be radio frequency (RF) communication but this is difficult to implement in aircraft due to regulations and also increases the cost and complexity of the lighting units which is undesirable.

Summary of the invention

In accordance with one aspect of the present invention, there is provided a method of modifying a lighting system in an aircraft comprising placing a control means or control element capable of selecting different light settings, such as 'dim', 'medium' and 'bright', into a data transmission mode, generating a stream of data signals i5 carrying programming information from the control means by selecting sequences of light settings of the control means, and transmitting the stream of data signals to reconfigure a light output of at least one light module, the light module typically comprising one or more light sources such as LEDs. This allows a plurality of light modules within an aircraft to be updated at once in selected groups and is of particular use for retro-fit lighting systems where no way of reconfiguring light modules is built into the electronic systems of the aircraft. The light modules are positioned throughout the aircraft, illuminating the ceiling and sidewalls of the aircraft.

The method may further comprise undertaking an initialisation procedure before placing the control means into a data transmission mode. The initialisation procedure provides a security step that ensures inadvertent operation of the data transmission mode is prevented.

The data signals are preferably generated at a very slow data rate, typically in the range 2 to 0.5 bits per second, with a particularly preferred rate being 1 bit per second.

The control means may be a rotary switch, switch, membrane keypad or touch screen.

The data signals may be generated using a coding scheme such as Manchester encoding.

In accordance with a second aspect of the invention, there is provided a lighting system for an aircraft comprising one or more light modules and a control means capable of selecting different light settings, wherein the control means is configurable to generate a stream of data signals carrying programming information for reconfiguring the light output of one or more light modules, typically comprising one or more light sources, such as LEDs.

The control means is preferably in communication with the one or more light modules using a control line along which the data signals are transmitted.

The one or more light modules may comprise a memory means for storing data Is signals generated by the control means.

The invention will now be described by way of example and with reference to the following drawings in which: Figure 1 is a schematic diagram of a lighting control switch; Figure 2 is a schematic diagram of a lighting module; and Figure 3 is a schematic diagram to illustrate a method of modifying a lighting system.

Description

Figure 1 shows a lighting control switch 10 found on an aircraft to control the lighting modules throughout the aircrafts. The switch can be a rotary switch, switch, membrane keypad or touch screen. There may be more than one switch if there are multiple lighting zones, for example a first zone in the cockpit, a second zone in first class, a third zone in business class and a fourth zone in economy class, with a switch controlling each zone Switch 10 can be moved to different positions 'off, 'dim', 'medium' and 'bright' shown as 12, 14, 16, and 18 and its position shown with a marker 20.

Figure 2 shows a lighting module or unit 22 that forms part of a lighting system on an aircraft and can be installed as a 'drop in' replacement for existing lighting units found on an aircraft. Each lighting unit 22 has one or more light sources 24, such as LEDs, providing one or more colours and one or more brightness levels. LEDs 24 are arranged inside an elongate housing 26 similar in form to a fluorescent lighting tube. Lighting unit 22 has a connector 30 that connects directly to an aircraft connector in place of the lighting unit that it is replacing and an internal processor or microcontroller 28 that controls LEDs 24. Microcontroller 28 sets the LEDs to predetermined levels of light output and/or colour in response to control inputs such io as 'Bright' or 'Dim'.

Microcontroller 28 stores data that represents the lighting settings for each mode it can be commanded to operate in and is configured to respond to the settings from lighting control switch 10. When control switch 10 is moved to a new mode, for Is example bright 18, light unit 22 will transition to the settings held for the bright mode of operation.

Microcontroller 28 has the inputs that come from the aircraft control switch 10 routed to it along control lines 32, shown schematically in Figure 3. There are varying numbers of these control lines or inputs depending on the type of aircraft, for example one or three inputs, and they are designed to be steady state discrete inputs. When the aircraft control switch 10 is operated, these inputs change state and then remain in that state until the switch is moved again. The software of microcontroller 28 inside lighting unit 22 is configured so that if it sees a predetermined sequence of control line changes within a predetermined period of time, it will begin monitoring the control lines looking for the predefined timing and transition sequences that have been assigned to 1 and 0 data bits and that represent a stream of data 34 sent from control switch 10.

Data message 34 is stored and read by microprocessor 28 to reprogram and so modify settings stored in the microprocessor memory to modify the lighting scheme, i.e. the colours and brightness levels associated with LEDs 24. Typically data message 34 includes a scheme of start/stop bits and typically parity similar to that seen in an RS232 transmission. Typically the data from control switch 10 is stored in microprocessor 28 until the next time the lighting scheme is modified.

Once microcontroller 28 begins monitoring the control lines, it enters a mode whereby it treats the input from the control switch 10 as a low data rate data bus. Changes in settings of control switch 10 are used to generate bits of data and so a stream of data carrying programming information to microprocessor 28. This can be done manually or by using an electro-mechanical or electrical device depending on the form of the control means 10. When generating data, and by way of example, a '1' data bit can be o generated and transmitted from control switch 10 to microprocessor 28 by a predetermined period of time in the 'bright' mode followed by a predetermined period of time in the 'dim' mode. If the predetermined period of time in bright is longer than the predetermined time in dim for a '1' data bit then a '0' data bit may be generated and transmitted, for example, by control switch 10 spending a shorter period of time in the bright mode than in the dim mode for example.

Given the architecture of the aircraft control system and the need for a robust data transfer, a very slow data rate is preferred, typically a rate of 1 bit per second to provide a good compromise between speed and robustness. This could be split as 0.3 second in bright followed by 0.6 second in dim for a 1' and the reverse for a '0'. An upper rate would be about 2 bits per second with no limit as to how slowly data could be transferred, although generally the lower rate would be 0.5 bits per second. The message sent by the control switch 10 would generally have around 100 bytes in it.

Alternatively a change from dim to bright can be used to generate a data bit, for example 0, and a change from bright to dim a data bit of 1 without any need for specific dwell times spent at dim or bright.

Control switch 10 thus generates a data stream 34 of bits that is sent to microprocessors 28 of all lighting units 22 associated with that switch 10. Typically there will be a plurality of units 22, see Figure 3, allowing many units to be simultaneously reprogrammed to change lighting output to a new lighting scheme without the need to visit each lighting module 22.

There are many variations on encoding schemes that are suitable for the transmission of a stream of data from control switch 10 over a data bus, Manchester encoding being an example which provides a way of dealing with possible inaccuracies between timing clocks at each end. For Manchester encoding, there is a data line transition in the middle of every data bit and the direction of this transition (high to low or low to high) determines if the bit is a '0' or a '1'. Given the transition always falls in the middle of the data bit, it is possible to recover the clock on each of these transitions. If two bits that are the same are to follow each other in the bit pattern then io the data line transitions between the bits to allow the same high to low or low to high transition to occur in the middle of the clock pulse. The disadvantage of using Manchester encoding is that it effectively doubles the number of bits to be transferred and halves the true data rate.

is Due to possible latencies in the control lines, in most cases an encoding scheme that effectively recovers a clock timing on each data bit, such as Manchester encoding, is preferable over a scheme such as that used in non-return-to-zero (NRZ) RS232 type transmissions or pulse position modulation (PPM) schemes.

In normal operation, it is undesirable for normal interactions with the control switch to cause unintended changes to the data settings stored by the lighting units. Thus an initialisation procedure can be configured to set the control switch to a data transmission mode and so provide a security scheme to prevent inadvertent changes to the lighting schemes of lighting units 22. One initialisation procedure could be to require a large number of control switch changes between predetermined modes within a short period of time. For example within one minute of being switched on, the control switch may have to be changed between bright and dim 20 times within 30 seconds to activate microcontroller 28 to treat the control line as a low data rate data bus providing a stream of data for reprogramming of the light scheme associated with lighting unit 22. More complex sequences of transitions could be used to further increase security.

Control mode signalling is normally a steady state input that changes a few times per flight, for example bright to medium. By using control mode signalling as a very low data rate communications bus for the transfer of 1 and 0 data bits to form messages, the present invention provides a means to change settings on multiple lighting units simultaneously. Control lines not usually intended for data transfer are used as a means to transfer data to reprogram lighting units.

Claims

Claims 1. A method of modifying a lighting system in an aircraft comprising placing a control means capable of selecting different light settings into a data transmission mode, generating a stream of data signals carrying programming information from the control means by selecting sequences of light settings of the control means, and transmitting the stream of data signals to reconfigure a light output of at least one light module.
2. A method of modifying a lighting system in an aircraft according to claim I, wherein the at least one light module comprises one or more light sources.
3. A method of modifying a lighting system in an aircraft according to claim 1 or claim 2, further comprising undertaking an initialisation procedure before placing the control means into a data transmission mode.
4. A method of modifying a lighting system in an aircraft according to any of the preceding claims, wherein the data signals are generated at a very slow data rate.
5. A method of modifying a lighting system in an aircraft according to any of the preceding claims, wherein the data signals are generated at a very slow data rate in the range 2 to 0.5 bits per second.
6. A method of modifying a lighting system in an aircraft according to any of the preceding claims, wherein the data signals are generated using a coding scheme such as Manchester encoding.
7. A lighting system for an aircraft comprising one or more light modules and a control means capable of selecting different light settings, wherein the control means is configurable to generate a stream of data signals carrying programming information for reconfiguring the light output of one or more light modules.
8. A lighting system for an aircraft according to claim 7, wherein each light module comprises one or more light sources.
9. A lighting system for an aircraft according to claim 7 or claim 8, wherein the control means is in communication with the one or more light modules using a control line.
10. A lighting system for an aircraft according to any of claims 7 to 9, wherein the one or more light modules comprises a memory means for storing data signals generated by the control means.