EMERGENCY LIGHTING FOR AIRCRAFT

Abstract

Title: AIRCRAFT EMERGENCY LIGHTING A photoluminescent aircraft ground marking system comprising at least one flexible track (400) having a housing incorporating a foldable and flexible photoluminescent portion, wherein the track (400) can be curved to a radius of 1 m or less and wherein the track (400) has a length of at least 2 m and wherein the track (400) is foldable so that it can retain a radius of curvature or bending. The track (400) can be curved to a radius of 0.01 m to 1.0 m or optionally from 0.01 m to 0.5 m. The flexible track (400) can be provided in lengths of 3 m or more or more than 10 m. A flexible protective layer may be provided. The flexible housing may include a support for the photoluminescent material. Figure to be published with the abbreviation: Figure 4

Description

Title of the invention: EMERGENCY LIGHTING FOR AIRCRAFT TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to aircraft emergency lighting typically intended for the interior of vehicles and especially relating to aircraft emergency exit ground lighting. The invention relates in particular to improvements in or relating to emergency lighting and in particular, but not exclusively, to emergency lighting used to indicate a retreat path leading to an exit for evacuation of a passenger vehicle in the event of an emergency following, for example, an accident.

[0002] The invention finds particular application in passenger vehicles and aircraft in particular of the type in which rows of seats are provided on either side of an aisle with an exit at one or both ends of the aisle and / or on one or both sides of the aisle between the ends of the vehicle. The invention is particularly applicable to aircraft in which emergency lighting systems are provided, in which photoluminescent material is incorporated in a track extending along the aisle for passengers to follow towards the exits. When exposed to light, the photoluminescent material is activated and emits light which is visible in conditions of darkened or low illumination from other light sources such as when smoke from a fire blocks overhead light sources.The level of illumination provided by the photoluminescent material is sufficient to guide passengers from their seats to an exit in order to evacuate the aircraft.

[0003] The present invention attempts to provide improvements to photoluminescent emergency lighting systems. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0004] Current prior art photoluminescent ground marking systems are typically provided in rigid or semi-rigid lengths of about 2 m (6 ft) due to limitations in terms of access to an aircraft cabin. It should be understood that it may be difficult to access an aircraft cabin through a door in the fuselage. Dimensional constraints of an aircraft fuselage restrict a possible length of rigid or semi-rigid housing or runway that can be used. Furthermore, it should be understood that an aircraft cabin has restricted access and limited side space for maneuvering lengths of housing or runway within the cabin. Adjustment mechanics are required. to install the lengths of photoluminescent system and cut lengths to the appropriate size. It should be understood that a joint must be provided between each length and an adjoining length. Each joint is a weak point where water and dirt can enter the photoluminescent marker system and cause additional wear. In addition, a joint can be aesthetically unappealing. Conventionally, joints must be used due to limitations on the maximum length of housing or track that can be used in an aircraft cabin. Typically, a maximum length is 2 m and it is therefore necessary to provide a joint every 2 m. Furthermore, it has been found that stowing rigid or semi-rigid tracks longer than 2 m is not desirable.Similarly, there is a significant expenditure of time and effort in laying the system with a large number of joints especially in a restricted area such as a driveway. It should be understood that it may also be difficult to remove one or more lengths, which is necessary if the runway has suffered damage during use of the runway in an aircraft. Summary of the invention

[0005] According to a first aspect of the invention, there is provided a photoluminescent ground marking system for aircraft comprising at least one bendable and flexible track incorporating a flexible photoluminescent portion, wherein the track can be curved to a radius of 1 m or less and wherein the track is bendable such that it can maintain a radius of wrap or curvature.

[0006] According to the invention, there is provided a photoluminescent ground marking system for aircraft comprising at least one flexible track having a housing incorporating a bendable and flexible photoluminescent portion, wherein the track can be curved to a radius of 1 m or less and wherein the track has a length of at least 2 m and wherein the track is bendable such that it can maintain a radius of winding or curvature.

[0007] Desirably, the track may be curved to a radius of 0.01 m to 1.0 m. More preferably, the track may be curved to a radius of 0.01 m to 0.5 m or 0.01 m to 0.1 m or 0.01 to 0.05 m. In some embodiments, the track may be curved to a radius of 0.05 to 0.5 m. It is to be understood that the track may be wound along the longitudinal length of the track. The axis about which the track is wound is perpendicular to the longitudinal length of the track. The axis may be parallel to a transverse direction across the track. It is to be understood that bendable means that the housing track material is flexible enough to bend freely or repeatedly without breaking. Further, it is desirable that the material be capable of winding and be capable of maintaining a radius of winding or bending, especially in storage mode. It is also desirable that the material be able to bend, preferably repeatedly, without cracking or wearing out as a result of bending.

[0008] In a preferred embodiment, the flexible track may be provided in lengths greater than 2 m or from 2 m to 4 m or from 3 m to 4 m. In other embodiments, the track may be provided in lengths of 4 m to 5 m or more than 5 m, preferably more than 10 m, more preferably more than 50 m.

[0009] A particular advantage of the runway in accordance with the invention is that the system can be installed as a single continuous runway section in an aircraft such as along an aisle. The runway can be provided in lengths greater than 2 m or 3 m or 4 m or greater than 5 m. In some embodiments, the runway is provided in lengths of 10 m or 25 m or 50 m or more such that a single length of runway can be applied along the length of an aisle.

[0010] In some applications, a length of 2 m or 3 m to 10 m may be preferred. A desired length may vary depending on an aircraft in which the runway is to be installed. In some aircraft, a distance between an emergency exit and an adjacent emergency exit may be about 10 m. For such an aircraft, it may be desirable to have a length of about 10 m.

[0011] It will be understood that the material used for the track may be such that the track is flexible and pliable, i.e., it can, for example, be rolled and stored in a coiled condition without springing back to a flat condition. Existing tracks are semi-rigid and although they can be bent to some extent without cracking, they will spring back to a flat condition and cannot be stored in a coiled condition. Such tracks cannot be considered flexible and pliable. A particular advantage of the present invention is that the material chosen has physical characteristics of flexibility and pliability that allow it to be bent or rolled and stored in the bent or coiled condition without a spring back force in the material forcing the track to return to a flat condition.It is desirable that the bendable track be capable of maintaining the winding or bending radius without any force being applied to overcome springback forces. It should be understood that a track that can be stored in a roll but is capable of unwinding may still be considered within the scope of the invention.

[0012] In some embodiments, the housing or track material may be pliable and may also comprise a polymeric smart material. A polymeric smart material is a material that has the ability to return from a temporary shape to an original shape under an external stimulus, such as a change in temperature. Such materials may also be known as called "shape-memory polymers" or SMPs. SMPs can be capable of retaining two or three shapes and can be arranged to transition between shapes under a change in temperature. An SMP can be arranged to have a different length under a first and second temperature and can be capable of repeatedly moving between the first and second lengths.

[0013] The flexible track comprises at least one housing. Preferably, the flexible track is adapted to be secured to a floor surface of an aircraft. The housing may comprise a flexible and foldable support which may be U-shaped or may be provided with "wings" arranged for overlay with a floor covering in an aircraft cabin. The "wings" may be flexible. The wings may also be foldable. It may be desirable to use an arrangement with "wings" to avoid a level stall which may be an obstruction to a trolley or other wheeled device moving in the aisle.

[0014] Those skilled in the art will understand that the runway is flexible in accordance with the invention. In known systems, a flexible insert was provided for insertion into a rigid or semi-rigid runway. In such systems, it is necessary to store lengths of runway ready for installation and such lengths must be handled and transported to an aircraft before installation. Those skilled in the art will understand that with a rigid or semi-rigid runway, a length of the runway is limited by the need to enter the aircraft with the runway. Entering through an aircraft door and negotiating installed galleys and seats limits a possible practical length of the rigid or semi-rigid runway to about 2 m.

[0015] Desirably, the flexible floor marking system may be provided in roll form. The flexible track is preferably arranged to be capable of being provided in roll form which may be used to lay down a continuous strip of the marking system. It will be understood that having a continuous strip reduces the time required to lay the track as it is no longer necessary to joint multiple sections. In addition, the number of joints is significantly reduced, thereby reducing problems with moisture and contaminant ingress. It will be understood that the roll may comprise a length of 3 m or a length of 4 m or a length of 5 m or a length of 5 to 10 m or more. In some embodiments, a roll may comprise a series of lengths.

[0016] The or each roll may be unrolled into place and the marker fitted to the aircraft floor. The runway may be unrolled along an aisle of an aircraft and cut to an exact size with few or no joints. Advantageously, the pliable material may be cut to length. Desirably, the pliable runway material is easy to cut. It is contemplated that rolls may be up to 200 m. In some embodiments, the rolls may contain longer lengths of photoluminescent markers and in still other embodiments, the rolls may contain a photoluminescent marker system of less than 200 m. Preferably, the roll is at least 5.0 m long or more preferably, at least 10 m long or more preferably, at least 50 m long. In a most preferred embodiment, the runway roll for the photoluminescent system is at least as long as an aisle of an aircraft.

[0017] In a preferred embodiment, the flexible floor marking system comprises a flexible photoluminescent material, and a housing comprising a flexible backing and optionally a flexible protective layer. In one embodiment, the flexible photoluminescent material may comprise a flexible substrate such as a vinyl or other flexible substrate. In some embodiments, the housing may be a flexible backing. The housing is arranged to be flexible. In some embodiments, the housing may be made of rubber or polyurethane, thermoplastic polyurethane, silicone, or a flexible epoxy resin. It is desirable that each of the housing, the photoluminescent material, the substrate, and the protective layer be bendable as well as flexible and capable of being stored in a coiled or bent condition.

[0018] In some embodiments, the track is formed of rubber, silicone, thermoplastic polyurethane, or thermoplastic polyurethane or elastomer. In some embodiments, the track includes at least one carpet wing.

[0019] In some embodiments, a flexible spacer may be provided to space the flexible floor marking system from a floor of an aircraft such that the marking system is substantially at a height of a carpet in the aircraft. The spacer may be provided with the flexible floor marking system or may be provided as a separate roll and be applied to the floor before the flexible floor marking system is laid.

[0020] In some embodiments, the photoluminescent material may be provided as an insert. In some embodiments, the photoluminescent material is provided as an insert and strips of the photoluminescent material are inserted into the housing and / or the photoluminescent material is coextruded or embedded within the flexible track. In some embodiments, cut strips of the photoluminescent material may be provided within the flexible and bendable housing of the track, such as a polyurethane housing. In other embodiments, the photoluminescent material may be coextruded with the bendable housing. In other embodiments, the photoluminescent material may be located within or secured to the housing.

[0021] In some embodiments, the photoluminescent material may be provided suspended in a plastic material. In some embodiments, the photoluminescent material may be provided in a suspension of thermoplastic polyurethane. The housing and the photoluminescent material may be provided as a unitary extrusion. The photoluminescent material may be provided in a suspension in a unitary extrusion. Suitable plastic materials for such extrusion may be selected from plastics such as thermoplastic polyurethane.Other suitable materials may be selected from at least rubber, silicone polyurethane, thermoplastic elastomers (TPE), thermoplastic elastomer polyurethane (TPE-U), thermoplastic polyurethane (TPU), thermoplastic olefins TPE-0 (cocontinuous hard / soft blend), TPE alloys, styrenic block copolymers (TPE-S), styrenic block copolymer compounds (SEBS, SEPS, SBS, SIS), thermoplastic copolyester (TPE-E), copolyester compound, thermoplastic polyamides (TPE-A), hydrogenated styrene block copolymers (HSBC TPE compounds). It should be understood that the "E" is often left out so that these compounds may also be referred to as TPO, TPS, TPV, TPE, TPU and TPA. .

[0022] Another material may be used provided that the material is transparent (or semi-transparent). In addition, the material must be a flexible polymeric material that can meet the requirements for flammability, smoke release, and toxic gas release that are required for aircraft applications.

[0023] The photoluminescent material may be provided in the form of coated particles to reduce abrasion properties of the photoluminescent material. A flexible protective coating may be applied over the photoluminescent material. In other embodiments, a flexible cover may be provided over the photoluminescent material. In some embodiments, the photoluminescent material may be provided as an insert arranged to be inserted into the housing or track. In other embodiments, this photoluminescent material may be provided in the plastic material of the housing.

[0024] It may be desirable to provide a marker system that has a pattern or color perceived in daylight or ambient light. The marker system may include a film that is colored or has a pattern in or on the film. Alternatively, the color may be integrated into the protective layer. The film or protective layer may include a pattern. In some embodiments, the film may be coextruded with the photoluminescent material.

[0025] In other embodiments, a pattern or color may be printed on the photoluminescent material or included in the protective layer.

[0026] It is desirable that the photoluminescent material be provided in a flexible substrate such as vinyl. Alternative flexible substrates may be used. The photoluminescent material may comprise photoluminescent phosphors or pigments. In preferred embodiments, the photoluminescent pigments comprise strontium aluminate doped with europium and / or dysprosium. A preferred embodiment is SrAl2O4:Eu2+,Dy3+ which produces green emission with maximum power at a wavelength of 520 nm. An alternative embodiment uses Sr4Ali4O25:Eu2+,Dy3+ which produces emission having maximum power at about 490 nm.

[0027] The housing is flexible and may be formed, for example, of rubber, TPU [thermoplastic polyurethane] or other TPE [thermoplastic elastomer]. Other suitable materials have been described earlier. Desirably, the photoluminescent material is retained within the housing. In a preferred embodiment, the housing holds the photoluminescent material in position and is arranged to connect to the protective layer. In some embodiments, the protective layer extends over the photoluminescent material but the housing does not extend over the photoluminescent material. In a further alternative arrangement, the photoluminescent material may be provided within the housing such that the housing material extends over the photoluminescent material.It is to be understood that where the track has a housing and a protective layer, the protective layer is also arranged to be flexible and bendable such that the track as a whole can be bent to a radius of 1 m or less and the track is bendable such that it can maintain a radius of winding or bending without the application of any force.

[0028] In a preferred embodiment, the protective layer is connected or secured to the housing. It is desirable that the protective layer extends over the photoluminescent material. The protective layer is designed to be flexible and robust. It is also preferred that the protective layer is arranged to be scratch resistant. It is preferred that the protective layer is selected from a material that is transparent or at least partially transparent to electromagnetic radiation from 300 nm to 750 nm or higher, preferably in the range of 400 nm to 600 nm.

[0029] In a preferred embodiment, the protective layer is transparent or partially transparent to light transmission in the range of 400 nm to 500 nm to allow charging of the photoluminescent material. In a preferred embodiment, the protective layer is transparent or partially transparent to light in the range of 300 nm to 750 nm.

[0030] It is preferred that the protective layer is transparent or partially transparent to electromagnetic radiation in the range of 450 nm to 600 nm and more preferably 400 nm to 600 nm to allow transmission of the luminescent light emitted by the photoluminescent material.

[0031] In a preferred embodiment, the protective layer is self-healing. The protective layer may comprise polyurethane. Desirably, the polyurethane is self-healing in the event of any physical damage. It is also desirable that the protective layer be chemically resistant. In some embodiments, the housing or track may be self-healing. It will be understood that a self-healing material is capable of correcting and / or repairing damage to the material without any external diagnosis of the damage from human intervention. It will be understood that self-healing materials are capable of counteracting cracks and damage that occurs due to natural degradation by initiating a repair mechanism that responds to the micro-damage and repairs the cracks, etc.It should be understood that a material that is able to regenerate naturally will have a longer useful life and will be able to reduce the impact of costly and time-consuming removal and replacement of the track or section of track.

[0032] In some embodiments, the marker system comprises a colored layer. The colored layer may be arranged to match the color of the marker system to that of the airline carpets and / or an airline livery. The colored layer may comprise a film or may comprise printing on the photoluminescent material or in or on the protective layer.

[0033] It is desirable that in the event of damage to the protective layer and / or the housing or the photoluminescent material, a damaged portion of the marker system can be removed and replaced.

[0034] It is contemplated that the flexible track may be readily laid in place along aisles and along branch lines such as toward emergency exit doors or through galley sections. The flexible and foldable nature of the marker system is such that the marker system may be stored on a roll and readily laid on an aircraft floor. Other means of storing and / or laying the marker system on the aircraft floor may be utilized by those skilled in the art. It is to be understood that this will facilitate installation and maintenance of the system for airlines using the marker system. It is anticipated that a roll of the marker system may be readily stowed by an airline to be ready for use in the event of damage to the installed system.

[0035] It is preferred that all materials of the marker system comply with the requirements of the CS25 safety standard. It is preferred that the system be made of a non-flammable material.

[0036] In some embodiments, the marker system is secured to the floor or carpet using an adhesive. In other embodiments, the marker system is secured to the spacer material, optionally using an adhesive.

[0037] According to a second aspect, there is provided a method of adjusting a flexible photoluminescent ground marking system in accordance with the first aspect of the invention comprising providing a roll of the flexible photoluminescent ground marker system; unrolling the marker system on a floor of an aircraft and securing the marker system to the ground.

[0038] In some embodiments, the marker system is secured to the floor using an adhesive. In other embodiments, a spacer is provided and secured to the floor and the marker system is secured to the spacer.

[0039] Desirably, a thickness of the spacer is chosen so that the flexible photoluminescent floor marking system is at a similar height to a mat laid on the floor.

[0040] In some methods in accordance with the invention, the marker system comprises a flexible track having a flexible photoluminescent insert. The track may further comprise a protective cover. In other embodiments, the insert may be received in a slot extending longitudinally within the housing. In some methods, the track may be installed on the floor of an aircraft in a first step. The photoluminescent material may be installed in the track in a second step. In other methods, the track may be provided with the pre-installed photoluminescent material. In some methods, the track may be provided with the photoluminescent material integral with the track housing.

[0041] According to a third aspect of the invention, there is provided an aircraft comprising a cabin having a flexible photoluminescent ground marking system installed in the aircraft cabin, wherein the system comprises at least one foldable and flexible track and a photoluminescent material housed in the track. BRIEF DESCRIPTION OF THE FIGURES

[0042] The invention will now be described by way of example only with reference to the accompanying figures in which:

[0043] [Fig. 1] [Fig. 1] is a perspective view of a marker system in accordance with the invention;

[0044] [Fig.2] [Fig.2] is a perspective view of an alternative marker system;

[0045] [Fig.3] [Fig.3] is a perspective view of an insert or track;

[0046] [Fig.4] [Fig.4] is a perspective view of a roller of the marker system in accordance with the invention, and

[0047] [Fig.5] [Fig.5] is a schematic indication of an aircraft with the system of marker installed. DETAILED DESCRIPTION

[0048] [Fig.l] illustrates a flexible photoluminescent ground marking system in accordance with the invention and comprising a flexible track 2 and a photoluminescent material 4 located in the track 2.

[0049] In this embodiment, the flexible track comprises a housing 6 adapted to be secured to a floor surface of an aircraft. The flexible track 2 comprises a central section 8 comprising a generally U-shaped section 9. The flexible track 2 further comprises laterally extending “wings” 10 arranged for overlay with a floor covering in an aircraft cabin. The “wings” 10 are made of a flexible and pliable material. In this embodiment, the “wings” are arranged to be unitary with the central section 8. The flexible track may be formed by extrusion. An arrangement with “wings” is advantageous because it avoids a level stall which may constitute an obstruction to a trolley or other wheeled device moving in the aisle of an aircraft cabin.

[0050] The housing 6 is arranged to be flexible. In some embodiments, the housing may be made of rubber or polyurethane, thermoplastic polyurethane, silicone, a thermoplastic elastomer, or a flexible epoxy resin. It is to be understood that the housing is flexible and bendable and capable of being stored in a coiled or curved state without springback forces returning the track to a flat condition. It is to be understood that the track is bendable such that it maintains a radius of winding or curvature.

[0051] The flexible floor marking system further comprises a flexible photoluminescent material 4. In this embodiment, the marker system further comprises a flexible protective cover 14. It is to be understood that the cover is optional but it is desirable that a protective covering be provided. The flexible photoluminescent material comprises a flexible substrate such as vinyl. In some embodiments, the photoluminescent material may be provided in the housing. The photoluminescent phosphor or pigment may be provided in the plastic material of the housing.

[0052] Although not illustrated, those skilled in the art will understand that a flexible spacer may be provided to space the flexible floor marking system from a floor of an aircraft such that the marking system is substantially at a height of a carpet in the aircraft. The spacer may be provided with the marker system at flexible floor or can be provided in a separate roll and applied to the floor before the flexible floor marker system is laid.

[0053] In some embodiments, the photoluminescent material is provided as a separate insert 208 shown in [Fig. 2] and as insert 30, shown in [Fig. 3], and may be provided as a separate continuous coil. Strips of the photoluminescent material may be inserted into the track. Insert 208 or 30 may be located in or secured to the housing 6 of the flexible track of [Fig. 1]. In other embodiments, the photoluminescent material may be coextruded with the housing. In other embodiments, insert 208 or 30 may be used as a track and applied directly to the floor of the aircraft. In such embodiments, the track may be secured to the floor of the aircraft using an adhesive or a filler material and an adhesive.Both the housing and the insert are arranged to be flexible and bendable so that the track and insert can each be bent to a radius of 1 m or less, wherein the track and insert are bendable such that each maintains a radius of wrap or bend.

[0054] The photoluminescent material may be provided in the form of coated particles to reduce abrasion properties of the photoluminescent material. A flexible protective coating 14 may be applied to the photoluminescent material 4 and secured in a central section 8 of the flexible track.

[0055] The photoluminescent material may be provided as a layer of photoluminescent material. In some embodiments, a reflective layer may also be provided as a base or undercoat. A coating or cover may be applied and may be arranged to be transparent to light that is emitted by the photoluminescent material and is further selected to be transparent or semi-transparent to wavelengths of electromagnetic radiation that charges the photoluminescent material 4.

[0056] The photoluminescent material 4 is provided in a flexible substrate such as vinyl. It is understood that alternative flexible and pliable substrates may be used. The photoluminescent material may comprise photoluminescent phosphors or pigments. In preferred embodiments, the photoluminescent pigments comprise strontium aluminate doped with europium and / or dysprosium. A preferred embodiment is SrAl2O4:Eu2+,Dy3+ which produces green emission with maximum power at a wavelength of 520 nm. An alternative embodiment uses Sr4Ali4O25:Eu2+,Dy3+ which produces emission with maximum power at about 490 nm.

[0057] In some embodiments, the marker system further comprises a film (not shown) that is colored and arranged to change the perceived color of a / the photoluminescent material. The film may operate by allowing only light of a certain wavelength to pass through the film. In other embodiments, the film may include a pattern. The film may be overlaid on the photoluminescent material 4 in the track or housing or may be coextruded with the photoluminescent material 4 or the track or housing or both. The color of the film may match that of an adjacent carpet or the film may be arranged to provide a desirable contrast. It is considered desirable to match the color and pattern on the film to that of the carpet in the aisle to avoid drawing attention to the emergency lighting system.

[0058] In other embodiments, a pattern or color may be printed on the photoluminescent material. Alternatively, a pattern or color may be embedded in the photoluminescent material. In other embodiments, the pattern may be provided in or on the protective layer. The pattern may be provided in a film that is anchored to the protective layer or coextruded with the protective layer. Those skilled in the art will be familiar with alternative arrangements such that a pattern or color is incorporated into an overlay for the photoluminescent material.

[0059] [Fig. 2] illustrates an alternative embodiment in which the track 200 includes a housing 202 having a longitudinally extending slot 204 within the housing forming the track. The track 200 is formed of a flexible material such as a thermoplastic polyurethane or a silicone or thermoplastic elastomer and is capable of being wound. The photoluminescent material 206 is provided in the form of an insert which is arranged to be a tight fit within the housing 202 which can then be secured into the central section 8 of the track 2 as discussed in connection with [Fig. 1] or in an alternative embodiment, the housing 202 can be secured directly to the floor surface of an aircraft cabin. The photoluminescent material 206 is, in some embodiments, provided in a vinyl layer and is flexible enough to be wound but has sufficient rigidity to be capable of being inserted within the housing.At least the upper portion 208 of the housing 202 is transparent or at least partially transparent to wavelengths emitted by the photoluminescent material and to wavelengths used to charge the photoluminescent material.

[0060] The marker system may be arranged to be secured to the floor or carpet by means of an adhesive. In other embodiments, the marker system is secured to the spacer material, optionally by means of an adhesive. A thickness of the spacer is chosen so that the flexible photoluminescent floor marking system is at a height similar to a carpet placed on the floor.

[0061] The flexible ground marker system 400 may be provided as a roller 402, as illustrated in [Fig. 4]. The roller 402 may be used to lay a continuous strip of the marker system 400 along the aisle of the aircraft. In use, the or each roll 402 may be unrolled into place in the aircraft and the marker system fitted to the floor of the aircraft. The track may be unrolled along an aisle of an aircraft and cut to an exact size with few or no joints. It is contemplated that the roll 402 of the track for the photoluminescent system may be as long as a section of an aisle of an aircraft. In a certain aircraft, each section may extend from a first emergency exit to an adjacent emergency exit. In some aircraft, such a section may, for example, be 10 m. In other aircraft, a section may be longer or shorter. It should be understood that some expansion joints may need to be provided. In use, an aircraft cabin may experience significant expansion and contraction in response to air pressure.It is understood that an aircraft cabin may expand in overall length during flight due to low external pressures. An advantage of the present invention is that the track may be arranged to stretch during flight and is capable of stretching with the expansion of the aircraft. The pliable materials are softer than previously used rigid or semi-rigid materials. The pliable materials are capable of stretching with the aircraft and are capable of returning to their original dimensions when the aircraft is at lower altitudes. The track may comprise a polymeric smart material (PSM). The track may be arranged to comprise a naturally regenerating polymer.

[0062] It is contemplated that in accordance with the second aspect of the invention, a roll 402 of the flexible track may be used in an aircraft cabin 500 as illustrated in [Fig. 5], to unroll the flexible track 400 and lay it in place along the aisles 504 of the aircraft. The track 400 may also be laid along branches 506 such as to emergency exit doors 508 or through galley sections and the track sections 400 may be joined together. The flexible nature of the marker system is such that the marker system may be stored on a roll and may be unrolled onto an aircraft floor. It is to be understood that this will facilitate installation and maintenance of the system for the benefit of airlines using the marker system.

Claims

Claims

1. A photoluminescent aircraft ground marking system (500) comprising at least one flexible track (2, 200, 400) having a housing (6, 202) incorporating a soft and flexible photoluminescent portion, wherein the track (2, 200, 400) is bendable to a radius of 1 m or less and wherein the track (2, 200, 400) has a length of at least 2 m and wherein the track (2, 200, 400) is pliable such that it (2, 200, 400) can maintain a radius of wrap or bend without any force being applied to overcome springback forces.

2. An aircraft ground marking system (500) according to claim 1, wherein the track (2, 200, 400) is curvable to a radius of 0.01 m to 1.0 m or optionally the track is curvable to a radius of 0.01 m to 0.5 m and optionally wherein the flexible track (2, 200, 400) is provided in lengths of more than 3 m or more than 4 m or more than 5 m or more than 10 m or more and optionally more than 50 m.

3. An aircraft ground marking system (500) according to any preceding claim, wherein the flexible ground marking system further comprises a flexible protective layer (14) and / or the flexible photoluminescent material (4) comprises a flexible substrate such as vinyl and / or the flexible housing (6, 202) comprises a support for the photoluminescent material (4).

4. An aircraft ground marking system (500) according to any preceding claim, wherein the track (2, 200, 400) is formed from rubber, silicone, thermoplastic polyurethane or thermoplastic polyurethane or elastomer (TPE).

5. An aircraft ground marking system (500) according to any preceding claim, wherein the photoluminescent material (4) is provided as an insert (30, 208) and strips of the photoluminescent material are inserted into the housing (6, 202) and / or the photoluminescent material (4) is coextruded or embedded within the flexible track (2, 200, 400).

6. An aircraft ground marking system (500) according to any preceding claim, wherein the system marking further comprises a film arranged to vary the perceived color from a color generated by the photoluminescent material (4) and optionally wherein the film is coextruded with the photoluminescent material (4).

7. An aircraft ground marking system (500) according to any one of claims 1 to 5, wherein a pattern or color is printed on the photoluminescent material (4).

8. An aircraft ground marking system (500) according to any one of claims 1 to 6, wherein: - a pattern or color is embedded in the photoluminescent material (4); or - a pattern or color is incorporated in an overlay for the photoluminescent material (4).

9. An aircraft ground marking system (500) according to any preceding claim, wherein the photoluminescent material (4) comprises pigments such as strontium aluminate doped with europium and / or dysprosium.

10. An aircraft ground marking system (500) according to claim 3 or any one of claims 4 to 9 as dependent on claim 3, wherein the protective layer (14) extends over the photoluminescent material (4) and optionally wherein the protective layer (14) is transparent or at least partially transparent to the transmission of light in the range of 300 nm to 750 nm or more preferably 400 nm to 600 nm.

11. An aircraft ground marking system (500) according to claim 10, wherein at least the protective layer (14) is naturally regenerating and optionally wherein the protective layer (14) comprises polyurethane.

12. An aircraft ground marking system (500) according to any preceding claim, wherein the runway (2, 200, 400) comprises at least one carpet wing.

13. A method of adjusting a photoluminescent aircraft ground marking system (500) in accordance with any one of claims 1 to 12, comprising providing a roll (402) of the flexible photoluminescent ground marker; the deployment of the marking system on the ground of an aircraft and the securing of the marking system to the ground.

14. A method according to claim 13, wherein the marking system is secured to the floor by means of an adhesive or wherein a flexible spacer is provided and secured to the floor and the marking system is attached to the spacer.

15. An aircraft (500) comprising a cabin comprising a photoluminescent ground marking system according to any one of claims 1 to 12.

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