GB2521659A

GB2521659A - Elongate LED lamp with indicator

Info

Publication number: GB2521659A
Application number: GB1323073.5A
Authority: GB
Inventors: Adrian David Charity; Xiaofeng Zhou; Geoff James Ledwith; Craig Pascoe
Original assignee: Novar ED&S Ltd
Current assignee: Novar ED&S Ltd
Priority date: 2013-12-27
Filing date: 2013-12-27
Publication date: 2015-07-01
Anticipated expiration: 2033-12-27
Also published as: GB201323073D0; GB2521659B

Abstract

An elongate LED lamp 10 has a tube 11 containing a circuit board 12 with an array of LEDs 13. These are connected to connection pins 16, 17 protruding through a first end cap 15. At the other end a second end cap 15 also has pins 18, 19 and these are connected to a status indicator 35 mounted on the circuit board 12 inside the tube. The status indicator 35 and pins 18, 19 of the second end cap 15 are electrically isolated from the LEDs 13 and the pins 16, 17 at the other end, by a section of circuit board 52 having no tracks. A lamp fitting (30, Fig. 5) mounts the elongate LED lamp, with the pins at each end inserted into respective sockets and supplies power to the pins 16, 17 of the first end cap and a status signal to the pins 18, 19 of the second end cap.

Description

ELONGATE LED LAMP WITH INDICATOR

The present invention relates to LED (light emitting diode) lamps and in particular to ones having an elongate form factor.

BACKGROUND

Fluorescent tubes are a longstanding form of lighting. This form comprises an elongate glass tube, with a seal at both ends, containing a low pressure gas. At both ends the seal has a pair of pins passing through it from the outside to the inside providing a feedthrough or electrical power. Each pin projects beyond the surface of the seal on the outside. In each pair the pins are joined, on the inside, by a respective electrode. The pins provide electrical connection to allow the device to be driven. Electric power passing between the pins of a pair serves to heat the electrode to provide thermionic emission of electrons. Electric power passing between the electrodes excites the gas, which produces visible light and/or other frequencies. The inside of the fluorescent tube is coated with a fluorescent material to convert, for example, ultra violet to visible light to improve the efficiency. In use, the lamps are mounted into a light fitting by inserting the pins into socket holes, which provide not only electrical connection but mechanical support as well.

More modern LED lamps are also produced in an elongate form factor.

A known form of elongate LED lamp 10 is shown in Figure 1. This resertles the traditional fluorescent tube in several respects. This is done so that the tube can be used in similar applications and environments and to ease user acceptance.

The LED lamp 10 has a translucent tube 11 of plastics material inside which is mounted a circuit board 12, which provides a mount and electrical connection for several LEDs 13, which provide the light. The circuit board is mounted via an elongate carrier 9 (Figure 2) , which has a cross section of an arc, of just smaller radius than the inside of the tube, having a slot 8 at each end of the arc into which the circuit board 12 is slid to assemble it.

In another otherwise similar known form of LED lamp, shown in cross-section in Figure 25A, the tube 11 and carrier 9 are replaced by hollow elongate support member llb and an elongate translucent cover ha. The support member is an aluminium extrusion having, in cross-section, an arcuate wall 7 with a wall 8 between the ends of the arc, the latter wall providing a mount for the circuit board 12.

Where those walls join it has elongate slots 6 which mount the elongate translucent cover. This has an arcuate cross-section with an inward facing elongate tab at each end of the arc. The tabs are slid into the slots 6 of the support member to assemble them together.

In both known LED lamps 10 the illumination LEDs 13 are connected on the circuit board 12 in series with PCB tracks 14; each set thus connected being called a "string". The number of LEDs is chosen to provide a convenient drive voltage, say for example 30V DC, however this is an arbitrary choice, subject to the maximum safe voltage allowed in a particular application. Several strings may be connected in parallel. (In Figure 1 two strings are shown connected in parallel.) At each end there is a cap 15 sealing the tube. Each end cap has a pair of metal feedthrough pins 16 and 17, and 18 and 19, completing the appearance of a traditional fluorescent tube. Further, the pins 16, 17, 18, 19 provide mechanical support when they are mounted into their light fitting 30 (Figure 3), in the same way as traditional fluorescent tubes, by inserting the pins 16, 17, 18, 19 into sockets holes 36, 37, 38, 39 respectively, respective pairs of which are provided by sockets 42, 43 at respective ends of the fitting 30.

However in the LED tube, the tracks of 14 of the circuit board 12, which supply the LEDs 13, need only a positive and negative DC electrical supply 31, which are connected to the pair of pins 16, 17 at one end only, with the pins 18, 19 at the other end being electrically unconnected. Inside the lamp, the connection between the pins 16, 17 and the tracks 14 is made by respective spring clips 4, which are attached to the end cap and connected to a respective pin; when the end cap is placed on the end of the tube the circuit board inserts into the clips, which make contact with the tracks. At the other end similar spring clips 5 are provided but only to engage the circuit board 12 mechanically -there are no tracks 14 on the circuit board at that point for the circuit board to connect to.

In order to ensure that the lamp 10 is mounted in the fitting 30 the right way round so that right pair of pins 16, 17 is connected to the 30V DC supply provided by the fitting in one socket 42, each end cap is also provided with a further pin 20, 21, of insulating plastics material, which also insert into socket holes 40, 41 of the respective sockets 42, 43, but the shape of those socket holes and the insulating pins are different at each end to prevent the lamp 10 being inserted into the fitting 30 the wrong way round. The insulating pins 20, 21 also prevent the LED lamp being inserted into fittings that are for traditional fluorescent tubes, which provide an unsuitable and dangerous AC supply at a much higher voltage.

The tube 11 (or assembly of elongate support member lib and elongate cover llb in the case of Figure 2E) of the LED lamp is filled with air at atmospheric pressure. A sealed tube is convenient to provide an environment for the LED which is stable and clean, but of course it is not essential to the operation of the device as it was with fluorescent tubes.

The typical fitting 30 for the LED lamp of Figure 1 is shown in Figure 3. This has a length of U-shape section, or box section, metal, forming a batten 32 which provides the mechanical strength and an enclosure for electrical components. The batten can be, for example, affixed to the ceiling or suspended on wires. Inside a power supply unit 33 converts mains electricity 28 to the 30V DC supply 31 to drive the LED lamp 10 and to charge a battery 34, which is used to power the LED lamp when the mains power fails. The sockets at each end comprising the socket holes are provided in respective socket fittings in the form of sprung plates 44 and 46 depending from the batten 32. These can be pushed apart to make room for the pins when the lamp 10 is being mounted into the fitting 30, and they return to their normal position once the pins are inserted in the socket holes.

Some lamp fittings 30 need to be provided with a status indicator, for example those designated as Emergency Luminaries. A control unit 29 (which may be integrated in the power supply 33) drives 50 a status indicator LED lamp 35 that indicates statuses such as that the lamp fitting is intended to be an Emergency Luminary, that it is powered, or that there is a fault, for example the battery is not charged. The status lamp 35 is mounted on the fitting 30 so that users and safety inspectors can see whether it is operating correctly. The LED status indicator lamp 35 is sometimes provided on a long lead so that if it not easily seen when mounted on the batten when that is sited for use, the indicator LED can be moved to an alternative location for example to a hole drilled through a nearly ceiling tile.

SUMMARY OF THE INVENTION

According to the present invention there is provided an LED lamp comprising: an elongate member, first and second pluralities of connection pins, the pluralities being mounted at respective ends of the elongate member, illumination LEDs connected to receive electrical power from the first plurality of connection pins, a status indicator mounted to the elongate merrber connected to receive a status signal from the second plurality of connection pins.

The first plurality of connection pins may comprise exactly two connection pins. The second plurality of connection pins may comprise exactly two connection pins.

The illumination LEDs and the status indicator may be electrically isolated from each other. The first plurality of pins may be electrically isolated from the second plurality of pins.

The status indicator may comprise an indicator lamp, which may comprise an LED. The indicator lamp may be capable of producing two different colours of light at different time. The indicator lamp may comprise a pair of LED lamps connected in parallel between the second a pair of the connection pins.

The elongate member may comprise a tube, which provides an enclosure, or alternatively the elongate member may comprise an elongate support member and an elongate cover, which provide an enclosure. The tube or the cover may be transparent or translucent.

The enclosure may contain the illumination LEDs and/or the status indicator.

The illumination tEDs and the status indicator may be mounted on a corrmon circuit board, which circuit board may be contained in the enclosure. The circuit board may have an electrically isolating section between the illumination LEts and the status indicator.

The present invention also provides a light fitting comprising: a support member first and second spaced apart sockets for receiving pins of a lamp, a power supply connected to the first socket to supply electrical power to the lamp to illuminate it, a control unit connected to monitor the operation of the fitting and to supply an electrical signal to the second socket indicating a status.

The light fitting may comprise a battery connected to be charged by the power supply and to provide the electrical power to the lamp to illuminate it on occasion.

The first socket may comprise a pair of socket holes to supply the electrical power to the lamp to illuminate it. The second socket may comprise a pair of socket holes to supply the electrical status signal to the lamp.

The light fitting of the invention may have fitted an LED lamp of the invention with its pins inserted into the first and second sockets of the fitting.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described with reference to the accompanying drawings, of which: FIGURE 1 is a perspective view of a known LED lamp, FIGURE 2A is a cross-section of LED lamp of Figure 1 in a first construction, FIGURE 2B is a cross-section of LED lamp of Figure 1 in a second construction, FIGURE 3 is a perspective view of a known lamp fitting, FTGURE 4 is a perspective view of an LED lamp in accordance with the present invention, and FIGURE 5 is a perspective view of a lamp fitting in accordance with the present invention.

EXAMPLES

A first example of an LED lamp 10' in accordance with the invention is shown in Figure 4. This is similar to the example of a known LED lamp of Figure 1.

The LED lamp 10' has a translucent tube 11 of plastics material inside which is mounted a circuit board 12' , via an elongate carrier 9 in the manner of Figure 2A, or it may be arranged to have an elongate support member llb and an elongate cover in the manner of Figure 2E. The circuit board 12' provides a mount and electrical connection for several LEDs 13, which provide the illumination provided by the lamp 10' . Again these LEDs are connected in series with 9GB tracks 14' . Two parallel strings of LEDs are provided in this example, and again the number of LEDs is chosen to provide a convenient drive voltage, say again for example 30V DC. (In the Figure two strings are shown connected in parallel) . At each end there is a cap 15 sealing the tube 11 (or sealing the assembly of lla and llb) . Each end cap has a pair of metal feedthrough pins 16 and 17, and 18' and 19', completing the appearance of a traditional fluorescent tube. These provide mechanical support when they are mounted in into their light fitting 30' (Figure 5), by inserting the pins 16, 17, 18', 19' into sockets holes 36, 37, 38', 39' respectively of a socket 42, 43' at either end of the fitting 30' In the LED tube, the circuit board 12' , is again connected to the pair of pins 16, 17 at one end. However in this case the pins 18' 19' are connected to an indicator 35' mounted as part of the lamp 10, via circuit tracks 51 on the circuit board 12' . The circuit board has an area 52 has an area between on one side the indicator 35' and its associated tracks 51 and on the other side the illumination LEDs and their associated tracks 14, which has no circuit tracks. This provides electrical isolation between two. (It also has no components with bodies in this area, which is preferred for it to be plain that there is no electrical connection spanning the area.) Similarly it provides electrical isolation between the pins 16 and 17 at one end and pins 18' and 19' at the other.

The status indicator is preferably an LED lamp. More preferably it is a package containing two LEDs, of different colour (or other visual property) connected anti-parallel (i.e. in parallel but with opposite connections of each LED's anode and cathode). The status signal is then provided with a first polarity to drive one of the two LEDs if it is desired to light that LED and with the other polarity if it is desired to drive the other LED of the package.

More generally the status indicator 35' could comprise any number of LEDs fed from pins 18' and 19' . A further alternative would be an electromechanical status indicator.

Generally the status indicator 35' is sufficient alone, however, another status indicator 35 can be provided in the batten, for example protruding from the batten as shown dotted at 35 in Figure 5, or on a long lead connected to the power supply for display elsewhere, for example protruding from a ceiling tile. The second indicator can be powered separately or in parallel (or series depending in the nature of the status signal) with the socket holes 38', 39' that supply the status indicator 35' in the LED lamp 10' Each end cap 15 is again also provided with a further pin 20, 21, of insulating plastics material, each of a different shape for insertion into corresponding socket holes 40, 41 of the respective sockets 42, 43' at the ends of the fitting. These now ensure that pins 16 and 17 receive the 30V DC power supply for the illumination LEns 13, and that pins 18' and 19' receive a status signal for the indicator. (They of course also help to prevent the LED lamp 10 being inserted into fittings that are for traditional fluorescent tubes.) The tube 11 of the LED lamp (or the assembly of elongate support member lib and elongate cover ha) is again filled with air at atmospheric pressure. A sealed tube is convenient to provide an environment for the LED which is stable and clean, but of course it is not essential to the operation of the device as it was with fluorescent tubes.

An exemplary fitting 30' for the LED lamp 10' of Figure 4 is shown in Figure 5. This again has a length of U-shape section, or box section, metal forming a batten 32 which provides the mechanical strength and an enclosure for electrical components. As before, the batten can be, for example, affixed to the ceiling or suspended on wires. Inside a power supply unit 33 converts mains electricity 28 to the 30V DC supply 31 to drive the illumination LEDs 13 of lamp 10' . A battery 34, charged by the DC power supply 31, is also provided therein, which is used to power the illumination LEDs 13 of LED lamp 10' when the mains power fails. Sockets 42 and 43' at respective ends of the batten again are again provided in respective socket fittings in the form of sprung plates 44 and 46' depending from the batten 32. The sockets 42, 43' comprise the socket holes 36, 37, and 40, and 38' 39' and 41 respectively. The socket fittings 44 and 46' can be pushed apart to make room for the pins when the lamp 10' is being mounted in the fitting 30', and they return to their normal position once the pins are inserted in the socket holes.

A control unit 29 is provided (again within the batten 32 and powered by the DC supply 31) to provide a status signal. However, in this example the socket holes 38', 39' are connected to supply the status signal to the indicator 35' that forms part of the lamp 10' The socket holes 38', 39' receive the status signal from the control unit 29 via cables 50' from the power supply unit 33. When the LED lamp 10' is inserted in the fitting 30' the socket holes 38', 39' pass the status signal to the pins 18' and 19, which in turn pass it to the status indicator 35' The above examples of the invention have a simple connection of exactly two conductive pins 18' and 19' supplying the status signal, and further the status signal signals the indication to be made according to the direction of its voltage/current. The invention however may use other arrangements.

For example the two pins 18' ad 19' may provide a power supply for the indicator with a status signal superimposed thereon. The indicator is then arranged to interpret the status signal, for example using a logic circuit provided for the purpose, which operates the indicator accordingly.

In another example one or more pins additional to those shown in Figure 4 is provided at the indicator connection end of the lamp 10' through the end cap 15, with corresponding socket holes being provided in the socket 43' . The set of pins, including 18' , 19' and the additional pin(s), may then be used in various ways.

In a first example of this two of the pins at that end are connected to supply power to operate the indicator with a third providing a status signal, which is interpreted by a logic circuit, forming part of the indicator, which operates the indicator accordingly. (In this case of course one the power pins provides a reference or ground -10 -level for the status signal.) These signals are provided by the control unit 29.

In a second example using three or more pins the control unit signals the status by selecting a pair of the pins to supply power to according to the status to be indicated and the indicator has two or more indicator lamps, for example LEDs, each connected between a different combination of two of the pins. For example one status may be indicated by an LED connected between first and second of the pins and a second status by and LED connected between second and third of the pins.

In the above materials for the tube 11 and the cover ha have been described as translucent. They may also be transparent.

In Figures the lamp 10' has been shown as straight, but it the invention applies also to elongate curved lamps.

Claims

-11 -CLAIMS: 1. An LED lamp comprising: an elongate member, first and second pluralities of connection pins, the pluralities being mounted at respective ends of the elongate member, illumination tEDs connected to receive electrical power from the first plurality of connection pins, a status indicator mounted to the elongate member connected to receive a status signal from the second plurality of connection pins.
2. An LED lamp as claimed in claim 1 wherein the first plurality of connection pins comprises exactly two connection pins.
3. An LED lamp as claimed in claim 1 wherein the second plurality of connection pins comprises exactly two connection pins.
4. An LED lamp as claimed in any preceding claim wherein the illumination LEDs and the status indicator are electrically isolated from each other.
5. An LED lamp as claimed in any preceding claim wherein the first plurality of pins is electrically isolated from the second plurality of pins.
6. An LED lamp as claimed in any preceding claim wherein the status indicator comprises an indicator lamp.
7. An LED lamp as claimed in claim 6 wherein the indicator lamp comprises an LED.
S. An LED lamp as claimed in claim 6 or claim 7 wherein the indicator lamp is capable of producing two different colours of light at different time.
9. An LED lamp as claimed in claim 7 or claim 8 wherein the indicator lamp comprises a pair of LED lamps connected in parallel between the a pair of the connection pins.

-12 -
10. An LED lamp as claimed in any one of claims 1 to 9 wherein the elongate member comprises a tube, which provides an enclosure.
11. An LED lamp as claimed in claim 10 wherein the tube is transparent or translucent.
12. An LED lamp as claimed in any one of claims 1 to 10 wherein the elongate merrber comprises an elongate support merrber and an elongate cover, which provide an enclosure.
13. An LED lamp as claimed in claim 12 wherein the cover is transparent or translucent.
14. An LED lamp as claimed in any one of claims 10 to 13 wherein the enclosure contains the illumination LEts.
15. An LED lamp as claimed in any one of claims 10 to 14 wherein the enclosure contains the status indicator.
16. An LED lamp as claimed in any ofle of claims 1 bo 9 wherein blie illumination LEDs and the status indicator are mounted on a common circuit board.
17. An LED lamp as claimed in any one of claims 10 to 15 wherein the illumination LEDs and the status indicator are mounted on a common circuit board and the circuit board is contained in the enclosure.
18. An LED lamp as claimed in claim 16 or claim 17, wherein the circuit board has an electrically isolating section between the illumination LEDs and the status indicator.
19. A light fitting comprising: a support member first and second spaced apart sockets for receiving pins of a lamp, a power supply connected to the first socket to supply electrical power to the lamp to illuminate it, a control unit connected to monitor the operation of the fitting and to supply an electrical signal to the second socket indicating a status.

-13 -
20. A light fitting as claimed in claim 19 comprising a battery connected to be charged by the power supply and to provide the electrical power to the lamp to illuminate it on occasion.
21. A light fitting as claimed in claim 19 or claim 20 wherein the first socket comprises a pair of socket holes to supply the electrical power to the lamp to illuminate it.
22. A light fitting as claimed in any one of claims 19 to 21 wherein the second socket comprises a pair of socket holes to supply the electrical status signal to the lamp.
23. A light fitting as claimed in any one of claims 19 to 22 having fitted an LED lamp as claimed in any one of claims 1 to 18 with its pins inserted into the first and second sockets of the fitting.
24. An LED lamp as substantially as herein described with reference to, and as shown in, Figure 4.
25. A light fitting substantially as herein described with reference to, and as shown in, Figure 5.
26. A light fitting as claimed claim 25 having fitted an LED lamp as claimed claim 24 with its pins inserted into the first and second sockets of the fitting.