AU2013200772A1 - Lighting device - Google Patents

Abstract

An LED tube replacement for existing fluorescent tube lighting has the LED tube adapted to fit straight into old fluorescent tube-docking fittings, requiring no more than the removal of the starter associated with the fluorescent tube to be replaced, and replacement thereof with a conductive linking device that bypasses the ballast, and the insertion of the LED tube in the existing fitting. The invention provides a safe way of retrofitting fluorescent tube lighting with LED tubes, without exposing personnel carrying out such tasks to dangerously high voltages. 70 70' 60 A-A'/ 62 70 70' (a) (b) 110 108 106 112 N2 Al 114 PRIOR ART ,102 102 (a) 126 124 N N2 1144 (b)101018 120 FIGURE 3

Description

1 A Lighting Device Field of invention 5 [001] This invention relates to a lighting device comprising an array of light emitting diodes (LEDs) and a method of reducing the risk of electrocution. The invention extends to a method and means for preventing electric shock when LED lighting is being installed. Background to the invention [002] A few decades ago, fluorescent tube lights entered the home lighting and industrial [0 lighting scene. Thanks to their cylindrical design, they produced good quality light that was dispersed better than incandescent bulbs. Soon tube lights began to be used in warehouses, factories, offices, homes, indoor gardens, schools - almost everywhere that lights were needed. [003] Fluorescent tube lights are energy efficient - about three times as efficient as 15 incandescent bulbs. But LED tubes are much better. LED tube lights are an elongated source of light with low luminous intensity. Their distribution of light is superior and glare is significantly reduced, compared to other light sources. A 23 watt, 6 foot LED tube light can replace a fluorescent tube that consumes 60 watts. [004] Tube lights are used for their relative energy efficiency and this is also why LED 20 tube devices are found to be ideal replacements for fluorescent lighting. Their often long operating hours in high use areas such as subways, tunnels and factories give a high return on investment, and break-even can be less than a year in some situations. The long life of LED tubes yields significant savings in replacement and maintenance costs.

2 [005] The fittings for fluorescent tubes comprise opposed brackets, each having a pair of sockets for receiving the twin electrodes positioned at each end of the tube. The infrastructure comprised of these brackets and sockets had continued to be occupied by incandescent bulbs until the advent of miniature fluorescent tubes. Nowadays, LED 5 technology is replacing both. [006] A significant operating cost borne by operators of electric lighting relates to the nature of the light-emitting device being used. Light emitting diodes (LEDs) are rapidly replacing both incandescent and fluorescent lighting as the means of choice, because of greater energy efficiency, the perceived environmental benefits and compliance with [0 regulatory requirements. Energy efficiency impacts on profitability, by lowering overheads and benefits socio-economic stability by facilitating fewer workforce cutbacks. [007] An aspect of the replacement of fluorescent tubes with LED arrays is the safety of those performing the retrofitting. Some regulatory authorities have decreed that only licenced electricians may do this task, because of the danger of exposure to potentially [5 lethal voltages and electric currents. [008] Fluorescent lighting installations require ballasts to provide the striking voltage to start the fluorescent devices up. The ballast adds to the cost of lighting, increasing power consumption and providing an additional component to add to the failure risk of the unit or installation as a whole. LED tubes, by contrast, can work on low voltage currents and 20 therefore need no ballast (or choke).

3 Objects of the invention [009] It is an object of this invention to address the shortcomings of the prior art and, in doing so, to provide an retrofittable LED tube that is suitable for use in fittings designed for receiving a fluorescent lighting tube. 5 [0010] A further object of the invention is to provide method of reducing energy usage in lighting, through the installation of more efficient LED lighting units. [0011] Another object of the invention is to provide an LED lighting device that is adapted to be safely installable by any person without the need for a licensed electrician or electrical technician to be involved or present. [0 [0012] The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia or elsewhere as at the priority date of the present application. 15 [0013] Further, and unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense - that is to say, in the sense of "including, but not being limited to" - as opposed to an exclusive or exhaustive sense - that is to say meaning "including this and nothing else". 20 Summary of invention [0014] This invention provides a LED tube replacement for existing fluorescent tube lighting. The LED tube is adapted to be docked straight into the fitting for a fluorescent 4 tube, requiring no more than the removal of the starter associated with the fluorescent tube, the replacement thereof with a linking conductor device that bypasses the ballast, and the insertion of the LED tube in the existing fitting. [0015] According to a first aspect of the invention, there is provided a lighting device 5 comprising a housing having a translucent wall, a plurality of LEDs inside the housing, the LEDs being operatively connected to electronic driving means, two pairs of electrodes protruding from the housing, said housing being adapted to dock in operable mode into an existing fitting for a fluorescent lighting unit of substantially same dimensions, so that the electrodes are received into existing electrical sockets in such fitting, and wherein a first [0 pair of said electrodes is operatively connected for supplying power to the driver, and a conductor located within the housing connects the second pair, thereby establishing a current path between the second pair in use. [0016] In a preferred form of the invention, the housing has a tubular shape [0017] In a further preferred form of the invention, the housing has first and second [5 opposed ends, from which the pairs of electrodes protrude respectively. [0018] In an embodiment, the conductor is adapted to be of substantially like resistance to the electrodes to which it is connected. [0019] In an embodiment, the conductor comprises an elongate bar. [0020] In a preferred embodiment, the conductor comprises a generally flat plate. Further 20 preferably, the plate has a T-like shape. [0021] In a still further preferred form of the invention, the conductor is electrically isolated from all other circuitry in the housing.

5 [0022] According to the invention, the conductor is made from a copper alloy. An example of such an alloy is brass. [0023] In a yet further preferred form of the invention, there is provided a circuit-linking device for replacing a starter unit found in fluorescent lighting installations in which the 5 fluorescent tube units are being replaced. [0024] The linking device is preferably adapted to dock in operative orientation in a vacant socket for otherwise receiving a starter unit. [0025] In an embodiment, the linking device comprises a pair of electrodes arranged to be received in the vacant socket as would those of a starter unit, and connecting [0 the electrodes in electrically conducting relationship to provide a conducting link between them. [0026] In a further preferred form of the invention, the conducting link comprises resistance means. [0027] Preferably, the resistance means is selected to cause the link to have resistance 15 approximating that of a starter it replaces. [0028] According to a second aspect of the invention, there is provided a kit for use in retrofitting an existing fluorescent lighting fitting with an LED lighting device, said kit comprising a circuit-linking device to replace a starter associated with a fluorescent lighting installation, and an LED lighting device adapted for 20 installation into the existing fitting. [0029] In a preferred form of the invention, the LED lighting device is as described in 6 the first aspect of this invention. The conducting link is preferably as described in relation to the first aspect above. [0030] In an further as aspect of the invention there is provided an LED lighting device comprising a housing having a translucent wall, a plurality of LEDs inside the 5 housing, the LEDs being operatively connected to electronic driving means, two pairs of electrodes protruding from the housing, said housing being adapted to dock in operable mode into an existing fitting for a fluorescent light fitting of substantially same dimensions, so that the electrodes are received into existing electrical sockets in such fitting, wherein a first pair of electrodes is operatively [0 connected for supplying power to the driver, and a conductor connects the second pair, thereby establishing a current path between them in use. [0031] According to a fourth aspect of the invention there is provided a tubular LED lighting device comprising a tubular housing, wherein is housed a driver comprising 15 a PC board, having first and second terminals, a plurality of LEDs operatively mounted on said PC board, a first pair of electrodes extending from a first end of the housing and configured to be matingly received, in use, into a first pair of sockets located on docking means configured to receive a fluorescent tube of predetermined 20 dimensions, 7 a pair of electrical conductors operatively connecting the first and second terminals to respective electrodes of said pair, thereby forming an electrical current conducting path between said PC board and said electrodes; a second pair electrodes located at a second, distal end of the housing to extend 5 therefrom, and being configured to be matingly received into a second pair of sockets on said docking means; and conducting means located within the housing and interconnecting said second pair of electrodes, wherein the housing is configured such that said first and second electrode pairs [0 are oriented to be conductingly received in the respective mating socket pairs on said docking means in use. [0032] In an embodiment, the device further comprises ballast means. The ballast means includes both electronic and magnetic ballasts. [0033] In a preferred form of this aspect of the invention, the resistance means is 15 configured to replace a starter for use in starting a fluorescent lighting tube device. [0034] In a further preferred form of the invention, the device includes a second housing for accommodating the resistance means. [0035] In a preferred embodiment, the housing is adapted to dock with a socket for 20 receiving a starter being replaced.

8 [0036] According to a fourth aspect of the invention there is provided a method of replacing tubular fluorescent lighting with LED lighting, the method comprising the steps of providing an LED lighting device having dimensions and an external electrode arrangement suitable for docking with a fitting for receiving a tubular 5 fluorescent unit to be replaced, removing from the fitting a fluorescent unit being replaced, removing from its receiving socket any starter device associated with the fluorescent unit, providing a replacement device for the starter device capable of re-establishing a conducting path broken by removal of said starter device, inserting the replacement device into the starter-receiving socket in [0 operative orientation, and fitting said LED lighting device into said fitting, wherein said LED device comprises conducting means establishing direct electrical current path between a first electrode for receiving into a live socket and a second electrode for receiving in a neutral socket. [0037] Preferably, the replacement device comprises linking conductor means for [5 establishing an electrical connection between the externally protruding electrodes]. [0038] In a preferred form of the invention, the replacement device comprises a housing within which said electrical connection is established. [0039] In a still further preferred form of the method of this invention, the replacement 20 device is adapted in respect of size and dimensions for being received into the vacant starter-receiving socket means. [0040] In an embodiment, the said linking conductor is selected to be fusible under 9 current and voltage conditions deleterious to the LED lighting device. Brief description of drawings [0041] In order that the invention may be readily understood, and put into practical effect, reference will now be made to the accompanying figures. Thus: 5 Figure 1 shows in telescopically truncated perspective view a preferred embodiment of the lighting device of this invention, partially dismantled. Figure 2 is an illustration in perspective and sectional views of a circuit linking device for use with the lighting device of figure 1. Figure 3 is a concept circuit layout diagram of the device of figure 1 in conjunction with [0 the device in figure 2, wherein figure 3(a) illustrates a prior art circuit and (b) a circuit of the invention. Detailed description of the invention [0042] The invention is suitable for being applied to tubular LED light fittings of the T8 and T10 configurations, which are well known in the art. 15 [0043] The invention provides a LED tube device comprising a tubular housing. The housing may be in one of various shapes, typically an elongate round tube extending linearly, but alternatively it could be another shape, for example a curve such as a U-shape, or a horse-shoe bend, or a hollow square and the like. Its cross section may be oval instead of round, or rounded triangular, square or hexagonal as options. 20 [0044] The invention additionally provides for a circuit linking device for replacing the starter conventionally associated with a fluorescent light fitting.

10 [0045] With reference to the embodiment illustrated in figure 1, there is shown a truncated representation of the lighting device of the invention, which is designated generally by the number 10. It comprises a housing formed from a hull portion 12, which is shown having a generally round tubular cross-section at 16, and a slidably interconnecting 5 opposed cover 14, made of a translucent plastics material, in this case perspex. Cover 14 has rail formations 20, which slidably engage with complemental grooves 22 on hull 12, allowing the cover to be alternately withdrawn and closed. When so withdrawn to an at least partially open position, an array of generally block-like LEDs 24 is exposed. The LEDs are mounted by conventional means on a circuit board 26. Via the circuit board, the [0 LEDs are connected to a driver 30, shown partly withdrawn to protrude from the proximate end of hull 12. The driver comprises circuitry and software of conventional known design and configuration, suited to the task of driving the LED array in operative light-emitting mode. As driver 30 is supplied with power, typically from a mains power source delivering power at 240V and up to 10A, it comprises voltage reducing means of conventional design, [5 for lowering voltage to a desired safe level. [0046] End cap 32, here shown removed from its operative location at the proximate end of hull 12 fits snugly to the end portions of interlocking hull and cover parts 12 and 14 and thereby provides a protective closure for the housing contents. The hull includes threaded sockets 38, 38' for receiving screws (not shown) having apertures for passing through the 20 end cap terminal wall, to secure the end cap in place. [0047] Protruding from end cap 32 are a pair of electrodes 34, 34', configured to matingly engage in a docking orientation with a receiving socket (not shown) provided in a standard size supporting bracket for a fluorescent light tube. The end cap is shaped and adapted to fit 11 such bracket and facilitate engagement of the electrodes with the sockets in electrically conductive mode. [0048] Providing electrical current conducting paths between electrodes 34, 34' and terminals on driver 30 are conductor wires 36 and 36'. 5 [0049] In this embodiment, the array comprises two rows of LEDs, generally disposed in parallel to each other and to the rail engaging formations of hull 12. In alternative embodiments, there may be additional rows, such as the three rows found in a T10 type configuration, or fewer rows, depending on the lighting application. [0050] The number of LEDs per row will also be varied depending on the length of the [0 housing and the circuit board being used. [0051] In this embodiment, the hull is made of a corrugated extruded aluminium alloy and the cover of translucent plastics material, in this case a perspex. The translucent wall may alternatively be transparent rather than merely translucent. Alternative materials of construction include transparent perspex and glass. 15 [0052] To close the distal end of the device, over which cover 14 is shown in figure I to extend in partially withdrawn position, there is provided an end cap 40, defining a cavity 42 which is adapted in shape and configuration to slidingly engage with the distal ends of hull 12 and cover 14. In the end wall 44 which terminates cavity 42 are holes 46 for receiving fixing screws (not shown). The screws when fitted pass through their respective holes and 20 engage with the walls of receiving sockets located at the end of hull 12. These sockets are of the same type as sockets 38, 38' at the proximate end of the hull.

12 [0053] Mounted to rear wall 44 of cavity 42 is a conductor 48, which bridges the gap between a pair of external electrodes, which attach to the conductor at terminal points 50 and 50'. In this example, the conductor is made of brass and has a flat T-shape. In an alternative embodiment, it may assume a different shape, such as a simple bar creating an 5 electrically conducting path between the electrodes. The electrode is otherwise electrically isolated from other circuitry in the device. [0054] Depending on the design demands of the lighting application in which the device of the invention will be used, the conductor bridging between the electrodes may optionally include additional resistor means. It may also include an additional terminal, such as on the [0 vertically oriented portion of the "T", for connection of an additional device, such as an electronic ballast. [0055] As in the case of proximal end cap 32, end cap 40 is shaped and its protruding electrodes positioned and configured to be easily received in corresponding conductor sockets in the infrastructure associated with a fluorescent tube of dimensions to which the [5 device of this invention is fabricated to correspond. [0056] It will thus be appreciated that the device of this invention is made to be retrofitted into mounting brackets designed for known fluorescent lighting tubes. Either end of the device may be inserted into either of the brackets without safety issues arising and without detriment to the circuitry of the device or of the premises containing the brackets. 20 [0057] Referring now to figure 2 there is shown a circuit-linking device generally designated with the number 60. It comprises a housing 62, in this case of round cylindrical shape, defining an internal space 64. In this embodiment the housing has a transparent wall 66 of a plastics material such as perspex, and an electrically non-conductive base 68, of an 13 opaque plastic. Mounted to extend through the base and project externally beyond the housing wall 66 are a pair of electrodes 70, 70". Connected to them and mounted on the inside surface 72 of the base are rigid electrical conductors 76 supportingly connected to a linking conductor 74, which, in this embodiment, is a fusible conductor. 5 [0058] The fusible conductor is selected to bridge the break in the electrical supply circuit feeding the lighting device, which was created by removal of the starter associated with prior fluorescent tubes, and thus close the circuit for powering the LED device of this invention. It is also optionally selected to be fusible under current and voltage conditions anticipated to be deleterious to the LED lighting device. [0 [0059] A ventilation aperture 78 is centrally located in the base, providing means for dissipation of heat. [0060] Figure 3 illustrates a circuit of the device according to the invention in (b), compared with a prior art circuit for atypical fluorescent tube fitting in (a). In (a), the circuit comprises wiring 102 connected to an alternating current power supply at 104. In older [5 fittings, a starter switch 106, may have been connected across electrodes Al and N2, which extend from fluorescent lighting tube 108. [0061] Inside the tube, a first discharge filament 110 is connected between pin electrodes Al-Ni and a second filament 112 is connected at the distal end of the tube between electrodes N2-A2. A ballast, choke or starter 114 regulates the voltage established between 20 the filaments. [0062] In figure 3(b), the fluorescent tube (108) has been replaced with an LED tube device 118 of the invention. The driver 120 is connected to electrodes Al and N1 and regulates the LED array 122. Conductor 124 provides electrical circuit continuity by 14 connecting electrodes N2 and A2. Apart from the substitution of the starter unit (106 in figure 3(a)), with a conducting circuit link 126, there is no need for further change. The effect of the ballast (114 in figure 3(a)), in cases where it is external to the fluorescent tube unit is compensated for by programming the driver to detect and reduce excessive voltages. 5 [0063] Since an LED tube operates on low voltage, a ballast is not needed in the circuitry of the installation. With prior LED tube devices, when a ballast was found, it was often necessary to rewire the tube light holder to eliminate the existing ballast from the electrical circuit. In this invention, a circuit in the LED tubes driver may optionally be included to counter and even nullify the effect of the ballast on the electrical supply, avoiding the [0 necessity of rewiring. The optionally included circuit serves to step down the voltage and condition the current by using known altering techniques. [0064] Some advantages of the present invention include the following: - The LED device is compatible with both starter and ballast, without leading to extra power being consumed; 15 - It is compatible with both magnetic and electronic or digital ballasts; - It directly replaces fluorescent lighting with a T8 LED tube; - No modifications to the existing light fittings are required, other than removing the old tube and its associated starter, and replacing these respectively with the T8 LED tube and circuit link of this invention. 20 [0065] Furthermore, the device is recommended for use in refrigeration apparatus and freezers in the temperature range from about -25 to +50 degrees Celsius. It is also suitable 15 for installation in premises such as hospitals, offices, shops, factories, and homes. Being mercury free (unlike fluorescent tubes), it reduces hazard risk wherever correctly installed. [0066] Known advantages of LED lighting over fluorescent lighting, which are enhanced by the present invention, include: 5 - Actual power consumption will spike higher with fluorescent fixtures when they are first switched on (started), or when the environment is cool. As the fluorescent tubes warm up, their efficiency rises. This spiking factor is not experienced with the LED tube system of the invention, increasing power savings. - LED tube devices require minimal maintenance, unlike fluorescent fixtures, which [0 require maintenance on the tubes, the ballasts and the starters, necessitating the calling out of an electrician in some jurisdictions. - Life expectancy of the LED units of the present invention is from about 30,000 to 50,000 hours of operation. For example if the lights are on for 10 hours per day and 7 days a week, the unit is found to have an average minimum operating life of 8.5 [5 years. By way of comparison, the life expectancy of a fluorescent tube ranges from 8,000 hours to no more than about 20,000 hours. [0067] These embodiments merely illustrate particular examples of the kit and product of the invention providing a retrofittable LED lighting unit. With the insight gained from this disclosure, the person skilled in the art is well placed to discern further embodiments by 20 means of which to put the claimed invention into practice.

Claims (33)

1. A lighting device comprising a housing having a translucent wall, a plurality of LEDs 5 inside the housing, the LEDs being operatively connected to electronic driving means, two pairs of electrodes protruding from the housing, said housing being adapted to dock in operable mode into an existing fitting for a fluorescent lighting unit of substantially same dimensions, so that the electrodes are received into existing electrical sockets in such fitting, and wherein a first pair of said ) electrodes is operatively connected for supplying power to the driver, and a conductor located within the housing connects the second pair, thereby establishing a current path between the second pair in use.

2. A lighting device according to claim 1 wherein the housing has a tubular shape.

3. A lighting device according to claim 1 or claim 2 wherein the housing has first and 5 second opposed ends from which the pairs of electrodes protrude respectively.

4. A lighting device according to any one of the preceding claims wherein said conductor is adapted to be of substantially like resistance to the electrodes to which it is connected.

5. A lighting device according to claim 4 wherein the conductor comprises an elongate 0 bar. 17

6. A lighting device according to claim 4 wherein the conductor comprises a generally flat plate.

7. A lighting device according to claim 6 wherein the plate has a T-like shape.

8. A lighting device according to any one of the preceding claims wherein the conductor 5 is electrically isolated from all other circuitry in the housing.

9. A lighting device according to claim 8 wherein the conductor is made from a copper alloy.

10. A lighting device according to claim 9 wherein the alloy is brass.

11. A lighting device according to any one of the preceding claims further comprising a ) circuit-linking device for replacing a starter unit found in fluorescent lighting installations.

12. A lighting device according to claim 11 wherein said linking device is adapted to dock in operative orientation in a vacant socket for otherwise receiving a starter unit. 5

13. A lighting device according to claim 12 wherein said linking device comprises a pair of electrodes arranged to be received in the vacant, socket as would those of a starter unit, and connecting the electrodes in electrically conducting relationship to provide a conducting link.

14. A lighting device according to claim 13 wherein the conducting link comprises 0 resistance means. 18

15. A lighting device according to claim 14 wherein the resistance means is selected to cause the link to have resistance approximating that of a starter.

16. A kit for use in retrofitting an existing fluorescent lighting fitting with an LED lighting device, said kit comprising a conducting link to replace a starter 5 associated with a fluorescent lighting installation, and an LED lighting device adapted for installation into the existing fitting.

17. A kit according to claim 16 wherein the LED lighting device is as claimed in any one of claims I to 15.

18. A kit according to claim 16 or claim 17 wherein the conducting link is as claimed in ) any one of claims 11 to 15.

19. A tubular LED lighting device comprising a tubular housing, wherein is housed a driver comprising a PC board, having first and second terminals, a plurality of LEDs operatively mounted on said PC board, 5 a first pair of electrodes extending from a first end of the housing and configured to be matingly received, in use, into a first pair of sockets located on docking means configured to receive a fluorescent tube of predetermined dimensions, a pair of electrical conductors operatively connecting the first and second terminals to respective electrodes of said pair, thereby forming an electrical 0 current conducting path between said PC board and said electrodes; 19 a second pair electrodes located at a second, distal end of the housing to extend therefrom, and being configured to be matingly received into a second pair of sockets on said docking means; and conducting means located within the housing and interconnecting said second pair 5 of electrodes, wherein the housing is configured such that said first and second electrode pairs are oriented to be conductingly received in the respective mating socket pairs on said docking means in use.

20. The device of claim 19 further comprising ballast means.

) 21. The device of claim 20 comprising electronic ballast means.

22. The device of claim 20 comprising magnetic ballast means.

23. The device of any one of claims 19 to 22 further comprising resistance means configured to replace a starter for use in starting a fluorescent lighting tube device. 5

24. The device of claim 23 comprising a second housing for accommodating the resistance means.

25. The device of claim 24 wherein the housing is adapted to dock with a socket for receiving a starter being replaced.

26. A method of replacing tubular fluorescent lighting with LED lighting, the method 0 comprising providing an LED lighting device having dimensions and an external 20 electrode arrangement suitable for docking with a fitting for receiving a tubular fluorescent unit to be replaced, removing from the fitting a fluorescent unit being replaced, removing from its receiving socket any starter device associated with the fluorescent unit, providing a replacement device for the starter device capable 5 of re-establishing a conducting path broken by removal of said starter device, inserting the replacement device into the starter-receiving socket in operative orientation, and fitting said LED lighting device into said fitting, wherein said LED device comprises conducting means establishing direct electrical current path between a first electrode for receiving into a live socket and a second ) electrode for receiving in a neutral socket.

27. A method according to claim 26 wherein. the replacement device comprises linking conductor means for establishing an electrical connection between the externally protruding electrodes.

28. A method according to claim 27 wherein the replacement device comprises a housing 5 within which said electrical connection is established.

29. A method according to claim 27 wherein said replacement device is adapted in respect of size and dimensions for being received into the vacant starter-receiving socket means.

30. A method according to any one of claim 27 to claim 29 wherein said linking 0 conductor is selected to be fusible under current and voltage conditions deleterious to the LED lighting device.

31. An LED lighting device substantially as described herein with reference to any one or 21 more of the accompanying drawings.

32. A method of replacing tubular fluorescent lighting with LED lighting, the method being substantially as described herein with reference to any one or more of the accompanying drawings. 5

33. A kit for use in replacing tubular fluorescent lighting with LED lighting, the kit being substantially as described herein with reference to any one or more of the accompanying drawings.