Abstract:
A pathway lighting system has self-contained, battery up scaled lighting modules ( 20 ), each module including at least one secondary coil. A plurality of primary coils are housed within a carrier assembly ( 1 ) together with voltage circuitry ( 14 ). Primary and secondary coils, positioned in the carrier assembly and in the lighting modules and the respectively allow electricity to flow between these members. The secondary coil output voltage is able to be rectified with the use of a rectification circuit, housed in the lighting module. Upon a mains failure, a battery charger/changeover circuit would switch the power requirements of the light sources inside the pathway lighting module over to internal back up batteries.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is for entry into the U.S. national phase under §371 for International Application No. PCT/GB03/00837 having an international filing date of Feb. 28, 2003, and from which priority is claimed under all applicable sections of Title 35 of the United States Code including, but not limited to, Sections 120, 363 and 365(c), and which in turn claims priority under 35 U.S.C. §119 to Great Britain Patent Application No. 0206798.1 filed on Mar. 22, 2002. 
   TECHNICAL FIELD 
   The present invention relates to lighting system, particularly though not exclusively for use in emergency pathways. 
   BACKGROUND OF THE INVENTION 
   Existing emergency pathway lighting systems typically consist of a linear system whereby one section of pathway lighting supplies power to the next section. The creation of an illuminated pathway is therefore reliant on links between pathway modules. Generally, printed circuit boards, housed in pathway modules, adjoin each other via wire connections and therefore have an electrical means of interconnection. A central power supply unit, generally connected to the mains supply, supplies power the first lighting module, which in turn supplies power to the second lighting module, and so on. The power supply also has a battery back-up unit that is activated when there is a mains failure. 
   However, the prior art has many potential failure points. The presence of water in the central power supply, containing the emergency battery back-up could cause the back-up to short circuit, resulting in a complete failure of the pathway system. If either the electrical supply line from the battery back-up to the pathway system or any of the pathway modules links suffer a breach, then a failure of the pathway system from the point of breach will occur. If any individual pathway lighting module suffers from electrical damage, then the subsequent modules would fail. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide an improved lighting system. 
   According to the invention there is provided a lighting system comprising:
         a carrier for a primary source of electricity, including a plurality of primary coils;   a plurality of sealed lighting modules, each including
           at least one secondary coil, each for electro-magnetically linking with one of the primary coils; and   at least one light source.   
               

   While the primary source of electricity will generally be mains electricity, it may be any other electricity source. For example such as produced by a generator, or the main supply on a ship or an aircraft, or from a step down voltage from the mains. 
   Usually each lighting module will include a battery back-up, preferably together with suitable switch-over circuitry, such that if the primary source of electricity fails, the lighting module will function on battery power. Generally charging circuitry will also be provided for the battery. 
   Conveniently each lighting module can further be provided with rectification means, such that if the primary source of electricity is of ac this can be converted to dc for the light source, if necessary. 
   Typically the light source is at least one LED. For use as an emergency pathway lighting the light sources may be in the form of shapes. Advantageously the shapes are directional arrows. Alternatively the shapes are pictograms, for example indicating the position of a fire escape or fire extinguisher. In another alternative the shapes can words. 
   The modules are adapted to be housed in continuous castings. 
   According to a second aspect of the invention there is provided a sealed lighting module for use with a carrier for a primary source of electrictity, and having a plurality of primary coils, the lighting module comprising;
         a least one secondary coil for electromagnetic induction from a primary coil; and   at least one light source.       

   Usually each lighting module will include a battery back-up, preferably together with suitable switch-over circuitry, such that if the primary source of electricity fails, the lighting module will function on battery power. Generally charging circuitry will also be provided for the battery. 
   Conveniently each lighting module can further be provided with rectification means, such that if the primary source of electricity is of ac this can be converted to dc for the light source, if necessary. 
   Typically the light source is at least one LED. For use as an emergency pathway lighting the light sources may be in the form of shapes. Advantageously the shapes are directional arrows. Alternatively the shapes are pictograms, for example indicating the position of a fire escape or fire extinguisher. In another alternative the shapes can words. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which: 
       FIG. 1  shows a lighting system according to the present invention; 
       FIG. 2  shows in larger scale from  FIG. 1 , the positioning for electromagnetic induction between the primary coils and the secondary coils; 
       FIG. 3  is a schematic diagram of the lighting system of  FIG. 1 ; 
       FIG. 4  shows the system of the invention in use with a series of sealed lighting modules each housing an array of lighting elements; 
       FIGS. 5A–5H  show a variety of tracks for holding the lighting system; 
       FIGS. 6A–6C  show different arrangements of light sources according to the present invention; 
       FIG. 7  is a perspective view of a bulkhead-type lighting module according to the present invention; 
       FIG. 8  is a lighting module in the shape of a standard light bulb; 
       FIG. 9  is a lighting module in the shape of a baton; 
       FIG. 10  is a further lighting module incorporating a reflector; 
       FIG. 11  is a large lighting module designed for downward and outward lighting; 
       FIG. 12  is an end view of the lighting module of  FIG. 11 ; 
       FIG. 13  is a bottom view of the lighting module of  FIG. 11 ; and 
       FIG. 14  is a perspective view of the lighting modules of  FIG. 11 . 
   

   DETAILED DESCRIPTION 
   Referring to the drawings,  FIG. 1  shows the lighting system of the invention  1 . A carrier  10  is provided for supplying mains electricity  11  to the system  1 . Positioned along the carrier are primary coils  12 . The primary coils are fully encapsulated in the carrier and as such cannot be adversely Affected by on influx of water, for example during an emergency. The carrier is made from a suitable thermoplastic such as polycarbonate or polyproplyene. 
   The system also includes lighting modules  20 . The modules  20  include secondary coils  22  which electro-magnetically link to the primary coils  12  for inducing electricity flow in the lighting modules  20 . Battery back up  26  is also provided in the modules  20 . The carrier assembly also includes voltage-conditioning circuitry  14 . 
   The lighting modules  20  are designed to be sealed units to prevent the ingress of water or noxious gases that may cause failure of the circuitry. Thus, if the mains electricity fails, the lighting modules  20  will continue to function. This is important in an emergency situation, such as a fire, where it is important to direct people to the nearest exit or safety point. 
     FIG. 2  shows in larger scale from  FIG. 1 , the positioning for electromagnetic induction between the primary coils  12  and the secondary coils  22 . As discussed above, fully encapsulating the primary coils  12  and providing the secondary coils  22  in the fully sealed lighting modules, prevents the system from being susceptible to the ingress of moisture. Flow of electricity is induced in the secondary coils  22  by induction from the flow of electricity in the primary coils  11 , and as a result, both the primary coils  11  and the secondary coils  22  can be sealed and thus impervious to water. 
   As shown in  FIG. 3 , the lighting modules  20 , further include rectification means  24  for converting the ac current of the mains supply to dc current. A battery back up  26  is provided in each lighting module  20 , such that in the event of mains failure, the lighting module can be powered by the battery  26 . Change over circuitry  28  is provided to enable to battery to be charged when the mains electricity is functioning, and to power the lighting module in the event of failure thereof. 
   In an alternative, the battery and charging circuit can be provided as an “eco battery” whereby the light sources in the lighting module run on the power provided by the battery. When the power in the battery falls below a predetermined level the charging circuit switches to re-charge the battery and power the light sources via the secondary coils. 
   The lighting modules include light sources  30 . Typically, these will be LEDs. As shown two LEDs  30  are provided with a rectifier  31  to as voltage protection. However, other light producing devices such as standard light bulbs  33  or fibre optics can be used. Reflectors (not shown) may also be provided. As shown the lighting modules additionally include a sounding device  32  and sockets  34  for the connection of other devices. All the components are mounted on a printed circuit board. 
     FIG. 4  shows the system of the invention in use with a series of sealed lighting modules  20  each housing an array of lighting elements  30 . Each lighting module  20  is positioned with its secondary coil  22  arranged for electromagnetic induction from the primary coils  12  encapsulated in the carrier  10 . 
   One of the main advantages of the system of the present invention is that the lighting modules can be provided in a variety of different shapes and designs for use in particular situations or places.  FIGS. 5–14  give examples of particular lighting modules. 
     FIG. 5  shows a variety of tracks including the carrier can be provided for accommodating the lighting system  FIG. 5   a  is a carpet to smooth floor track;  FIG. 5   b  is a carpet to carpet track;  FIG. 5   c  is a carpet to wall track  FIG. 5   d  is a universal track;  FIG. 5   e  is a corner track;  FIG. 5   f  is a ramp track;  FIG. 5   g  is a hand rail track; and  FIG. 5   h  is a stair capping track. 
     FIG. 6  shows different arrangements of light sources from a secondary coil  12 .  FIG. 6   a  shows five light sources  30  arranged on a board  60  in the shape of a right angle or possible arrow head.  FIG. 6   b  shows the light sources  30  arranged on a board  62  in the shape of a cross; and  FIG. 6   c  shows the light sources arranged on a board  64  in the shape of a T-piece. 
     FIG. 7  is a bulkhead-type lighting module. As described above, the module  70  is a sealed unit and is provided with a secondary coil  72  for the electromagnetic induction from the primary coil in a carrier (not shown). In addition back-up batteries  74 , and a battery indicator,  76  are provided. Light sources  78  are also provided with a reflector  79  to enhance and direct the lighting effect thereform. 
     FIG. 8  is a further lighting module, this time in the shape of a standard large light bulb  80 . As before the module includes a secondary coil  82  for interaction with a primary coil on a carrier  83 . Back-up batteries are provided inside the unit (not shown) and a battery indicator light is also provided  84 . LED light sources  86  are provided on a printed circuit board  87  beneath a lens face  88 . The choice of lens can result in the module being either a flood light, a spot light, a beam light or the like. 
   In the embodiment shown in  FIG. 9 , a lighting module is shown in the shape of a tubular light bulb  90 , or batton. It is provided with a secondary coil  92  for connection with a primary coil of a carrier (not shown). The body  94  of the module is provided as a sealed unit, and including the battery back up, rectification circuitry, charging circuitry as described above. The module also has a battery level indicator  96 . A plurality of LEDs  98  are arranged along the centre of the module. 
     FIG. 10  shows a lighting module  140  designed in the form of a standard light bulb. The module includes a secondary coil  142  for induction from a primary coil on a carrier  143 . Light sources  144  are housed in chambers  145  at one end of the module. A fibre optic bundle  146  is provided in each light source with their end collectors arranged to convey light from the light source  144  through the fibres  147 . The fibres pass convey light from the light sources  144  to a reflector  148  provided at the other end of the module. A lens  149  is also provided to enhance or direct the light from the module. 
     FIGS. 11–14  shows are large lighting module  150  in accordance with the invention. An array of LEDs  151  is provided around two edges  152 ,  153  of a sealed unit, for illumination both outwards and downwards from the unit. As with the lighting modules described above, this module is a self contained sealed unit. It is provided with a secondary coil  154  for electromagnetic induction from a primary coil on a carrier as shown in  FIG. 1 . Inside the unit, not shown are back-up batteries, as described before. So that the user can be confident that the back up battery is fully charged, a indicator light  156  is provided to indicate that the battery holds sufficient power. Again, as with the lighting modules described earlier, this lighting module  150  includes the rectification, change-over and battery charging circuits described above, not shown. 
   The invention is not intended to be restricted to the details of the above-described embodiment. For instance, the lighting modules and the carrier can be provided in many other shapes and designs for use in particular situations.