Abstract:
A light emitting diode lighting device and system that can be used for illuminating the interior and/or exterior of vehicles, aircraft, watercraft, signage or buildings is provided. It includes a voltage feedback constant current power supply circuitry and high power LEDs. The printed circuit assemblies are firmly mounted onto a continuous or semi-continuous mounting channel case that also works as a heat sink. By this means, it not only increases the reliability of the LED lighting tube but also it provides sufficient heat dissipation capability for the heat generated by the LEDs. Since the operating temperature of the LEDs is controlled and stays in cool condition, it dramatically increases the LED&#39;s lifetime and efficiency. The end caps of this LED lighting device are fully compatible with existing conventional fluorescent light fixtures and can directly replace those fluorescent lighting tubes in vehicles, mass-transit, watercrafts, aircrafts, signage, furniture, equipment or buildings with minimal modifications.

Description:
BACKGROUND 
     The presented LED lighting system relates in part to a retrofit and direct replacement of conventional fluorescent lighting tubes with light emitting diode (LED) lighting devices for usage in vehicles, including mass-transit vehicles such as buses, trains, subway trains, also for lighting watercrafts, aircrafts, signage, furniture, equipment or buildings using LEDs. 
     For many years the lighting of interiors of vehicles, aircraft, buildings, signage, and watercraft, and more recently the lighting of exteriors of vehicles, and signage have use the cold cathode lamp; more commonly known as the fluorescent lamp or a fluorescent system. The fluorescent lamp however has limitations on its capabilities and usages. The fluorescent lamp has disadvantages to the consumer. The disadvantages of the fluorescent lamp are the short life, easily broken, low durability, high costs of replacement, high costs of specialty lights, limited color selection, electromagnetic interference (EMI) which may be harmful to other electronic equipment. The manufacturing of fluorescent lamps and debris from replaced lamps have a high environmental risks, as the chemicals inside of a fluorescent lamp are toxic. Also the flicker effect of dying or improperly installed fluorescent lamps may be extremely harmful to individuals with certain medical conditions. The constant inconsistency of fluorescent lighting colors is often a complaint of consumers who have to replace lamps on a regular basis. A fluorescent system cannot be used effectively in extreme low or high ambient temperatures. 
     To attempt to avoid difficulties with fluorescent lighting, proposals have been made to use LEDs as replacements for fluorescent lighting, as for example described in U.S. Pat. No. 6,860,628 issued Mar. 1, 2005 and U.S. Pat. No. 6,583,550 issued Jun. 24, 2003. While these devices do provide some of the advantages of LEDs, there remains a need for lighting systems that can supply sufficient illumination to meet lighting requirements in vehicles, including mass-transit vehicles such as buses, trains, subway trains, also for lighting watercrafts, aircrafts, buildings and signage without excessive heat build up, while reducing the amount of lamps, wiring, ballasts, power consumption and maintenance that fluorescent systems require. 
     SUMMARY 
     There is therefore provided a variety of light emitting diode lighting devices and systems that can be used for illuminating the interior and/or exterior of vehicles, aircraft, watercraft, signage or buildings is provided. The system in one embodiment may include a voltage feedback constant current power supply circuitry and high power LEDs. In one embodiment, the power supply circuitry is provided on printed circuit assemblies firmly mounted onto a continuous or semi-continuous mounting channel case that also works as a heat sink. By this means, it not only increases the reliability of the LED lighting tube but also it provides sufficient heat dissipation capability for the heat generated by the LEDs. Since the operating temperature of the LEDs is controlled and stays in cool condition, it dramatically increases the LED&#39;s lifetime and efficiency. The end caps and pins of this LED lighting device are in some embodiments fully compatible with existing conventional fluorescent light fixtures and can directly replace those fluorescent lighting tubes in vehicles, mass-transit, watercrafts, aircrafts, signage or buildings with minimal modifications. 
     In various embodiments of the LED lighting systems described here, there may for example be a support structure forming a channel and being heat conductive and rigid, with one or both ends of the support structure having electrical connectors for connection to a power source. An LED array in some embodiments extends along the support structure for example within the channel, and in some embodiments supported in slots, each LED in the LED array may have in some embodiments a power rating of greater than 0.1 watt. The power supply circuitry in some embodiments is provided by current control circuitry, for example onboard circuitry, carried by the support structure, in some embodiments within the channel, and may provide current control for individual sets of LEDs. The current control allows careful control of the forward current passing through the LED array so that it controls the brightness and heat production by the LEDs. Devices with full 360 degree illumination are disclosed, along with devices with LEDs having differently angled illumination fields. Various electrical power supplies, structural support configurations and shapes, lens configurations, and overall structural configurations are also disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There will now be described embodiments of an LED lighting system, with reference to the drawings, by way of illustration only, in which like numerals denote like elements and in which: 
         FIG. 1  is a cross cut view from inside of single pin type LED lighting system; 
         FIG. 2  is a cross cut view from inside of ‘bi-pin’—two pin type LED lighting system; 
         FIG. 3  is a cross cut view from inside single or ‘bi-pin’—two pin type of LED lighting system showing permanent, for example, rivet or screw, mounting; 
         FIG. 4  is an end view of single pin type of LED lighting system; 
         FIG. 5  is an end view of recessed double contact base, two pin type LED lighting system; 
         FIG. 6  is an end view of ‘bi-pin’, two pin type LED Lighting Tube; 
         FIG. 7  is a top view of single pin design, one end cross cut, to view interior configuration; 
         FIG. 8  is a top view of single pin design, with lens; 
         FIG. 9  is a top view of recessed double contact base-two pin design, one end cross cut, to view interior configuration; 
         FIG. 10  is a top view of recessed double contact base-two pin design, with lens; 
         FIG. 11  is a top view of ‘bi-pin’—two pin design, one end cross cut, to view interior configuration; 
         FIG. 12  is a top view of ‘bi-pin’—two pin design, with lens; 
         FIG. 13  is a block diagram of single series of electronics (1.5V˜72V) for onboard current control; 
         FIG. 14  is a block diagram of multi series of electronic configuration (1.5V˜72V) for onboard current control; 
         FIG. 15  is a 3-D view of the LED Lighting tube, without end fittings; 
         FIG. 16  is a 3-D side view of the LED Lighting tube, without end fittings; 
         FIG. 17  shows an LED lighting system in a mass-transit application, bus shown here for reference purposes, new or retrofit application; 
         FIG. 18  shows an LED lighting system in a vehicle application, taxi side view, for taxi advertisement sign; 
         FIG. 19  shows an LED lighting system in a vehicle application, taxi top view, for taxi advertisement sign; 
         FIG. 20  shows an LED lighting system in a vehicle application, taxi front view, for taxi advertisement sign; 
         FIG. 21  shows an LED lighting system in a vehicle application, taxi side view, for taxi ‘on-duty’ sign; 
         FIG. 22  shows an LED lighting system in a vehicle application, taxi top view, for taxi ‘on-duty’ sign; 
         FIG. 23  shows an LED lighting system in a vehicle application, taxi front view, for taxi ‘on-duty’ sign; 
         FIG. 24  shows an LED lighting system in an airplane application, cross cut view of fuselage; 
         FIG. 25  shows an LED lighting system in an airplane application, bottom view of fuselage; 
         FIG. 26  shows an LED lighting system in a mass-transit application, cross cut view of bus; 
         FIG. 27  shows some examples of lenses for the LED lighting system; 
         FIG. 28  shows an LED lighting system in a fluorescent lamp, replacement, retrofit, or new installation; 
         FIG. 29  is a top view of vehicle application LED lighting system, powered end; 
         FIG. 30  is an end view of vehicle application LED lighting system, powered end; 
         FIG. 31  is a cross cut view of vehicle application LED lighting system, powered end; 
         FIG. 32  is a Top view of vehicle application LED lighting system; 
         FIG. 33  is an End view of vehicle application LED lighting system; 
         FIG. 34  is a cross cut view of vehicle application of LED lighting system; 
         FIG. 35  is a block diagram of current control electronics for a high voltage application, single series (73V˜240V); 
         FIG. 36  is a block diagram of current control electronics for high voltage application, multiple series (73V˜240V); 
         FIG. 37  is a signage application, with a view of replacement of fluorescent lamps in signage; 
         FIG. 38  is a cross cut view of an LED lighting system with LED arrays facing different directions; 
         FIG. 39  is a view of multiple sections of an LED lighting system with LED arrays facing different directions; 
         FIG. 40  is a section through a embodiment of an LED lighting system with 360 degree coverage; 
         FIG. 41  is an exploded view of the embodiment of  FIG. 40 ; 
         FIG. 42  is a section through a further embodiment of an LED lighting system with 360 degree coverage; 
         FIG. 43  is a section of an end socket for use with an LED lighting system; 
         FIG. 44  is a perspective view of the embodiment of  FIG. 43 ; 
         FIG. 45  is an exploded view of the embodiment of  FIG. 42 ; 
         FIGS. 46-49  are a series of sections of an LED lighting system showing how various configurations of LED arrays may be carried by a support structure; 
         FIG. 50  is an exploded view of the embodiment of  FIG. 48 ; 
         FIG. 51  is a perspective view of a mounting bracket that may be used with the embodiments of for example  FIGS. 46-49 ; 
         FIG. 52  is a section through an embodiment of an LED lighting system with a domed support structure; 
         FIG. 53  is an exploded view of the embodiment of  FIG. 52 ; 
         FIG. 54  is a section through a further embodiment of an LED lighting system with a domed support structure; 
         FIG. 55  is an exploded view of the embodiment of  FIG. 54 ; 
         FIG. 56  is a section through a further embodiment of an LED lighting system with differently angled LED arrays; 
         FIG. 57  is an exploded view of  FIG. 56 ; 
         FIG. 58  is a section through a further embodiment of an LED lighting system with differently angled LED arrays; 
         FIGS. 59-65  show a variety of end sockets for use with LED lighting systems; 
         FIG. 66  is a section through a further embodiment of an LED lighting system with 360 degree coverage; and 
         FIG. 67  is an exploded view of the embodiment of  FIG. 66 . 
     
    
    
     DETAILED DESCRIPTION 
     In this patent document, “comprising” means “including”. In addition, a reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims. 
     In  FIGS. 1-3 ,  7 - 12 , there is shown an exemplary LED lighting system  10  that includes a plurality of LEDs  100 , each LED  100  being supplied power from a circuit board  101  supported by support structure  102 . Support structure  102  in one embodiment forms a channel and is made of a heat conductive and rigid material, such as aluminum, ceramic or any thermally conductive formable material. In one embodiment, the support structure  102  is both heat conductive and rigid and is made of a unitary piece of material. The support structure  102  is rigid and extends from end to end of the LED lighting system  10 . The heat sink capability may be continuous from end to end or may be semi-continuous. In the case of being semi-continuous, the material providing the heat sink function may have breaks, in which case additional connector material is required to provide the channel with sufficient rigidity so that the lighting system  10  does not collapse or sag under its own weight. The circuitry  20  or  30  provide current control for the LED lighting system  10  and are attached to the support structure  102  permanently such as by fasteners  108  ( FIG. 3 ), which may be rivets or screws, so they do not allow for vibration to loosen the connection between the circuit board  101  and the support structure  102  over time. The support structure  102  does not require adhesive, or thermally conductive substance to connect to the circuit board  101 . The support structure  102  provides a rigid backbone structure to the LED lighting system  10 , and is sufficiently rigid to prevent the LED lighting system  10  to resist or prevent breakage during normal use, or bending, unless the product design requires it. The support structure  102  may be provided with a cover  107  secured in a groove  109  that runs along the inside edge of the support structure walls. The cover  107  is transparent or translucent and may be formed as a lens. 
     At one or both ends of the support structure  102  there are provided electrical connectors  103 ,  105 , and  106  for connection of the lighting system  10  to a power source. When LED lighting system  10  is configured as a bulb, rather than as tube, it will typically have connectors only at one end. In the embodiment of  FIGS. 1 ,  4 ,  7  and  8 , a single connector  105  of Pin Type 1 is formed in end caps of the support structure  102 . In the embodiment of  FIGS. 2 ,  5 ,  6 , and  9 - 12  double connectors  106  of Pin Type 2, either in the bi-pin format ( FIGS. 6 ,  11  and  12 ) or the recessed double contact type ( FIGS. 5 ,  9  and  10 ) are formed in end caps  104  of the support structure  102 . These connectors  105 ,  106  are of conventional design. The end caps  104  may be any suitable material such as plastic, Lexan™, polycarbonate, acrylic, ABS, metal such as aluminum, copper, brass, stainless steel, metal alloy, combination of metal and plastic, or fiberglass. The end caps  104  may be manufactured in different shapes and sizes, all able to connect to the circuit boards  101  within the support structure  102 . The end caps  104  encase the channel, are secured against movement and do not break with vibration. The end caps  104  also secure and prevent movement of the lens  107 ,  118 - 127 . As with the other components of the lighting system  10 , the end caps  104  should be made to withstand high ambient temperatures (up to 125° C.+) and low ambient temperatures (as low as −40° C.). In the case of use of the LED lighting system  10  as a fluorescent light fixture replacement, the connectors  105 ,  106  are conventional pins for attached to fluorescent light fixture receptacles. In other embodiments, such as when the LED lighting system  10  is used in a single socket fixture, the connectors  106  may be provided at one end only of the support structure  102 . 
     An LED array formed of LEDs  100  extends along the support structure within the channel formed by the support structure  102 . To provide sufficient power to provide light, particularly in an industrial or commercial environment, each LED  100  in the LED array should have a power rating sufficient to provide the desired degree of light, including in the case of vehicles used for transportation a sufficient degree of light to meet regulatory requirements. For example, such requirements may be met by LEDs having a power rating of greater than 0.1 watt, depending on the efficiency of the LED in converting power to light energy. The LEDs may also be organic LEDs or any other suitable LED now known or later developed. 
     The circuit boards  101  provide in one embodiment onboard current control circuitry for the LED array. The circuit boards  101  are carried by the support structure  102  and are in electrical communication with the electrical connectors  103 ,  105 ,  106 . The LEDs  100  are preferably organized in groups of LEDs, either in series, or parallel. The LEDs may be surface mounted (SMT) or through hole mounted (TH). The colour of the LEDs can be any available colour such as white, blue, green, red, yellow, amber, purple, pink, or orange. 
       FIGS. 13 and 14  show circuit diagrams with an example circuit  20  for onboard current control. The circuits of  FIGS. 13 ,  14 ,  35 ,  36  may all be placed on the circuit board or boards  101 .  FIG. 13  illustrates a single circuit  20  connected to a conventional power source  208 , while  FIG. 14  shows multiple circuits  20  in parallel connected to a conventional power source  208 . The circuit boards  101  for the circuits  20  may be made of fiberglass based printed circuit board (PCB) or metal based (for example Aluminum) PCB or any other suitable PCB material now known or later developed. The circuit boards  101  may be TH type or SMT type. Preferably, the surface of the circuit boards  101  have a white solder mask and exposed areas of tinned plane so as to efficiently reflect the majority of LED light. The circuit boards  101  may be flexible to accommodate mounting channels and lighting fixtures in different shapes and curves. As shown in  FIGS. 13 and 14 , the LED array is divided into sets  209  of LEDs, with for example five LEDs per set. As shown in  FIG. 14 , the onboard current control circuitry is formed of multiple circuits  20 . Each circuit  20  provides current control for a corresponding set  209  of LEDs in the LED array. 
     The onboard current control circuitry  20  is configured to provide constant current to the LEDs  100  of the LED array  209 . A polarity protection circuit  201  of conventional design safeguards against the user installing the product in the wrong polarity. Current control is provided by current control circuit  202 , also of conventional design. As an example, the current control circuit  202  may be use pulse width modulation (PWM) to control the current supplied to the LEDs. The circuit  202  supplies constant, controlled, current to unit for the entire LED set  209  with information from voltage sensor  203 . The voltage sensor  203  receives current information from LEDs  209  and feeds back information to the current control circuitry  202 . For example, in the use of PWM, the voltage sensor  203  converts the current of LED array  209  to voltage signal and supplies the voltage signal to the current control circuit  202 . The current control circuit  202  senses how much the detected voltage varies from the desired level, and by varying the pulse width or frequency, changes the current supplied to the LEDs towards the desired level. The power supply  208  may be AC or DC, although in the example shown it is DC. Current control provides constant brightness and prevents overheating. A typical pulse frequency for the current control may be 200 kHz to 4 MHz. This low voltage application shown here provides voltage for applications below about 72 volts. 
     The organization of the circuit boards  101  is shown in  FIGS. 15 and 16 .  FIG. 15  shows a single set of five LEDs  100  with circuit components  201 ,  202  and  203 .  FIG. 16  shows an exploded side view of an LED lighting system  10 , with support structure  102 , cover  107  and with LEDs  100 , which LEDs may be for example secured or joined to a circuit board  101  by any suitable means as for example soldering or heat sink compound  117 . 
       FIG. 17  is an example of an LED lighting system or tube  10  in a mass transit application. A transit vehicle has a body or hull  303  with a windshield  300 . The break away shows floor  304 , with seating  306  and partitions  305 . Lighting tubes  10  may be installed in pre-existing fluorescent light sockets or receptacles  309 , with bypassing or removal of the fluorescent light ballasts  308 .  FIG. 26  is another view of the mass transit application, showing also passengers  310  and a reading plane  311  and floor plane  313 , which acts as a test zone for establishing whether the LEDs are providing sufficient illumination.  FIGS. 18 ,  19  and  20  illustrate an application in which the LED lighting system  10  is used as part of an advertising sign  401  for a taxi  400 .  FIGS. 21 ,  22  and  23  illustrate an application in which the LED lighting system  10  is used as part of an on duty sign  404  for a taxi  400 .  FIGS. 24 and 25  illustrate installation of the LED lighting system  10  in new or pre-existing fluorescent light fixtures of an aircraft with a fuselage  500 , seating  501 , windows  502 , upper luggage compartment  503 , cargo area  504  and floor  505 . 
     In  FIGS. 27A-27K , various shapes of cover lens  107  are shown including moderate convex  124 , straight  107 , straight raised  118 , asymmetrically peaked  119  and  120 , symmetrically peaked  121 , raised dome  122 , low dome  123 , convex  124 , depressed low dome  125  raised convex  126 , and low dome with channel enclosing  127 .  FIG. 28  shows a fluorescent lamp fixture  600  with power receptacles or sockets  601 , conventional ballast  602  for lamp  603 , replacement LED lighting tube  10 , ballast cover  604  and diffuser panel  605 . While the lens  107  is not required for the final assembly it can be added to act as a guard against vandalism, as a dust/dirt guard, as a light enhancing device, as a light directing/focusing device, as a moisture/waterproofing device (sealing unit completely with the addition of sealant) or as a light diffuser. In  FIG. 28 , only the lighting tube  10  is new.  FIG. 37  shows replacement of a fluorescent lamp  603  in a display sign application with an LED lighting tube  10  that fits between power receptacles  601 . The ballast  602  may be removed or bypassed. 
     In  FIGS. 29-31 , powered end of an LED lighting tube for a vehicle application includes LED  100  (one of several in the array), support structure  102 , connecting wires  103  that connect to the circuit board  101  and rivets  108  for securing the circuit board  101  on the support structure  102 . The connecting wires  103  pass through the holes  114  in O-rings  110  that are secured to the upstanding flange of an inner mounting bracket  116 . The mounting bracket  116  is secured to the support structure  102  by a bolt  113  secured with nuts  112  and washer  111 . Bolt  113  and nuts  112  also secure outer mounting bracket  115  to the support structure  102 . Rivets  108  also secure the side walls of the mounting bracket  116  to the channel walls of the support structure  102 . Mounting bracket  115  is used to connect the LED lighting tube of this embodiment to a structural portion of a vehicle.  FIGS. 32-34  show the non-powered end of the LED lighting system for a vehicle, which is the same as the powered end except that there are no power connections. 
       FIG. 35  shows electrical circuitry  30  of an current circuit, and  FIG. 36  shows several such boards connected in parallel between respective power buses.  FIGS. 35 and 36  show circuitry for a high voltage power source, above 72 volts, for example 120 volts to 240 volts, either AC or DC. The example shown here is for AC power supply. Fuse  215  protects the circuitry of the board from power surges. The fuse can be permanent or be a resettable fuse. Bi-directional filter circuit  204  filters out noise. Full wave rectifier  205  transforms AC current from the power bus (left side of figure) to DC current. The DC current from the full wave rectifier  205  is supplied to voltage regulator  207  to step the voltage down to a low level, for example 5 volts, to power switching power supply control IC  210 . The switching power supply control IC  210  provides a modulated signal at about 250 kHz or more that determines the switching frequency or pulse width of a high voltage switching power driver circuit  211 . The switching signal from driver  211  drives a primary coil of transformer  216 , and causes DC voltage supplied by the full wave rectifier  205  to switch at the switching frequency or pulse width determined by the control IC  210 . Transformer  216  couples this switching voltage through half-wave rectifier  206  which also filters the high frequency signal from the transformer  216  to the LED array  209  on the right side of  FIG. 35 . The half-wave rectifier  206  provides the switching frequency or pulse width of the current from the secondary of the transformer  216  and supplies a isolated feedback signal through a signal feedback circuit  212  to control IC  210 . Depending on whether the sensed signal is above or below the desired current level, the control IC  210  varies the pulse width or pulse frequency of the signal driven by the driver circuit  211  to ensure a constant average current supplied to the LEDs. The transformer  216  both isolates input from the output, which drives the LEDs, and provides a voltage step down from high voltage above 72 volts, to low voltage required by the LED array  209 . The control IC  210  may also be configured to vary the average current supplied to the LEDs, by suitable controlling the pulse width or frequency of the drive signal to the circuit  211 , and thus provide a dimmable controller that can be used to control the brightness of the lighting devices. The switching power supply circuit  30  may be mounted on each circuit board  101 , or shared by each of several circuit boards  101  and located at one end of the lighting device  10 . 
     The switching power supply circuit  30  is integrated with the LEDs  100  on each section of printed circuit board  101 , so that any defect of each power supply circuits or LEDs  100  would not affect the lighting device  10  as a whole. The other circuit boards  101  of the lighting device are still active. The LED lighting device  10  can be installed in polarity or no polarity, and may have any required length. The LED lighting device  10  may use voltages from 1.5V˜240V in both DC and AC, and may fit retroactively into existing fluorescent lighting fixtures after removing or bypassing the ballast. This LED lighting device  10  can be a replacement or retrofit for all existing fluorescent lighting tubes larger than the size of T5. 
       FIG. 38  and  FIG. 39  show two different views of an embodiment of an LED lighting system in which the LEDs  100  lie on flat PCB heat sinks  134 . The LED arrays are attached to the flat PCB heat sinks with each of the LED arrays facing in a different direction. Each LED array contains a series of LEDs, each with a conical beam, that together create an illumination field. The orientation of the illumination fields of the LED arrays shown in  FIGS. 38 and 39  are angularly offset from each other by 90 degrees. In other embodiments, this angle may change, and/or individual LEDs may have conical beams that are angularly offset from each other. Additional LED arrays may also be provided, with each LED array having a differently oriented illumination field. In one embodiment, the illumination fields of three or more LED arrays may together make up a 360 degree pattern. In the embodiment of  FIGS. 38 and 39 , an 180 degree lens  133  with guides is attached to the support structure  136  in channel  109 , and may slide into place along the channel  109 . In  FIG. 39 , two PCB heat sink slots  135  are formed in the support structure  136 . The heat sinks  134  fit in the slots  135 . Heat from the heat sinks  134  is in part conducted to the support structure  136  to assist in heat dissipation. A suitable heat conductive material such as aluminum may be used for the heat sinks  134  and support structure  136 . 
       FIGS. 40 and 41  show a further embodiment of an LED lighting system with 360 degree coverage in which the support structure  137  defines two channels and the LEDs  100  of two LED arrays on circuit boards  101  have illumination fields at 180 degrees to each other. A double sided lens  130  is received in channel  109  in the support structure  137 . Grooves  131  on the outside of the support structure are provided for receiving a mounting clip such as mounting clip  115  shown in  FIG. 51 . Mounting clip  115  has arms  138  with hooks  139  that insert into the grooves  131 . The clip  115  may be secured by any suitable means to the structure  137  such as a part of the surface to which it is mounted. 
       FIGS. 42 and 45  show a further embodiment of an LED lighting system with 360 degree coverage similar to the design of  FIG. 66 , but the lens covers  129  are omitted, and the locking elements  128  are also omitted, the cylindrical lens  127  being used to secure the elements together. 
       FIGS. 43 and 44  shows an end socket for use with an LED lighting system  10  which uses two pins  106  secured within an inner mounting channel  116  inside an end cap channel  132 . This end socket may be used with the designs of hollow support structures (or at least partially hollow) such as those of  FIGS. 42 ,  45 ,  66  and  67  with the channel  116  protruding into the hollow support structure  140  or  147 . 
       FIGS. 46-50  show how various configurations of LED arrays may be carried by a support structure  141 . In these figures, the support structure  141  is the same in each case, and may be provided with one or two semi-cylindrical lenses  133  received in slots  109  running along the length of the support structure  141 . Mounting clip grooves  131  are provided on the outer sides of the support structure  141 . There may be one ( FIG. 46 ), two ( FIG. 47 ), three ( FIG. 48 ) or four ( FIG. 49 ) circuit boards  101  carrying LEDs  100  in linear arrays that may be directly secured to the support structure  141  or placed on flat PCB heat sinks  134  that are received in angled slots  135  running along the length of the support structure  141 . In this way, the orientation and number of the LED arrays can be selected according to the application. 
       FIGS. 52-55  show a variety of LED lighting systems with a domed support structure  142  and  144 . A 180 degree lens  143  has guides that are received in grooves  109  in the support structure  142  and  144 . An LED array formed of LEDs  100  on circuit boards  101  in one 180 degree embodiment ( FIG. 52 ) is received in slots  135  on the front side of the support structure, and on the opposite rear side a power supply  30  may be secured by any suitable means within the domed portion of the support structure  142  and  144 . In another embodiment ( FIG. 54 ), the LEDs of respective circuit boards  101  have illumination fields that are oriented at different angles, though both illumination fields are perpendicular to the direction of elongation of the support structure. The direction of the illumination field is the direction perpendicular to the light emitting surface of the LEDs  100 . The embodiments of  FIGS. 52-55  may be connected to fixtures by end cap channels  132  as for example shown in  FIGS. 59-61 . 
       FIGS. 56 and 57  show further embodiments of an LED lighting system with differently angled LED arrays. In this embodiment, the support structure  145  may be mounted by clips with lips that are received in grooves  131 . The embodiment of  FIG. 58  is an example of an LED lighting system with 360 degree illumination field generated by four LED arrays at angles to each other, with semi-cylindrical lenses  133 , and also that may be mounted on a mounting clip. 
       FIGS. 62-65  show a variety of end sockets for use with LED lighting systems, showing support structure  102 , end cap  104 , pin connector Type 1  105 , and end cap channel  132 . 
       FIGS. 66 and 67  show an embodiment of an LED lighting system with 360 degree coverage. In this embodiment, there are four LED arrays each secured to one piece of a two piece hollow support structure  147 . In this example, the support structure  147  forms four channels at the base of which circuit boards  101  holding the LEDs  100  are fixed by any suitable means. The four channels are defined by four arms of the support structure  147 . Lens covers  129  are received in slots running the length of the arms and are provided with openings for the LEDs. The LEDs protrude into the openings. A cylindrical lens  127  surrounds the support structure  147 . The two pieces of the support structure  147  are held together by locking elements  128 . 
     Immaterial modifications may be made to the embodiments described here without departing from what is claimed.