GB2389893A

GB2389893A - Lighting device

Info

Publication number: GB2389893A
Application number: GB0214065A
Authority: GB
Inventors: James Edward Campion
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-19
Filing date: 2002-06-19
Publication date: 2003-12-24
Anticipated expiration: 2022-06-19
Also published as: GB0214065D0; GB2389893B

Abstract

A lighting device (10) comprises a set of spaced conductors (12), each of which is looped or substantially looped, at least one light emitting device (14) held by, and in electrical communication with, the spaced conductors (12) which are preferably unshielded wire, means for supporting the spaced conductors and means for supplying electrical power to the spaced conductors to electrically energise the light emitting device(s) (14). The supporting means may comprise a base (26) and a plurality of elongate support conductors (28).

Description

1 2389893

LIGHTING DEVICE

This invention relates to a lighting device.

5 It is often desirous to temporarily light or illuminate a specific area, such as a dining table, to create a suitable ambiance. It is well-known to do this by the use of candles or mains powered lamps with filament type bulbs.

However, the flame of a candle can be dangerous, especially when left ] O unattended or with children in the vicinity, and mains powered filament type bulbs are extremely hot and may be accidentally touched. Furthermore, both candles and bulbs have limited life-spans, candles being generally shorter than filament type bulbs.

Candles can also leave soot deposits on surfaces, and filament bulbs emit ultra-violet radiation which, over time, can lead to fading of colours in fabrics and paintings.

The present invention seeks to overcome these problems.

According to one aspect of the present invention, there is provided a lighting device comprising a set of spaced conductors, each of which is looped or substantially 20 looped, at least one light emitting device held by, and in electrical communication with, the spaced conductors, means for supporting the spaced conductors, and means for supplying electrical power to the spaced conductors to electrically energise the light emitting device(s).

( 2 Preferable and/or optional features of the present invention are set forth in claims 2 to 24, inclusive.

lithe present invention will now be described, by way of example, with 5 reference to the accompanying drawings, wherein figure I is an upward perspective view of one embodiment of a lighting device, in accordance with the present invention, 10 Figure 2 is an enlarged view of part of the lighting device shown in Figure 1, and Figure 3 is an enlarged view of part of the lighting device shown in Figure 2.

15 Referring to the drawings, a lighting device 10, typically in the form of a table lamp, is shown. The lighting device 10 comprises three separate sets of spaced endless conductors 12, and three light emitting devices 14 held by each set of endless conductors 12, so that each light emitting device 14 is in electrical communication with each endless conductor 12 of its respective set.

Each endless conductor 12 typically takes the form of an elongate element 16, such as a wire, which is joined end-to-end. The elongate element 16 is flexible enough I to be formed into a shape, but is rigid enough to he able to retain that shape once formed. Each endless conductor 12 is formed into an annular or substantially annular

shape, such as a circle. However, each endless conductor 12 may be formed into a polygonal or substantially polygonal shape, such as a triangle or a square, or any suitable shape or combination of shapes.

5 Each endless conductor 12 is formed from an electrically conducting material, such chrome-plated or nickel-plated steel, and is unshielded. By use of the term unshielded', it is meant that the endless conductor 12 is exposed and has no electrically insulating, typically plastics, protective sheathing covering the conductor, unlike other typical electrical conductors.

The inner and outer endless conductors 18 and 20 of each set of endless conductors 12 are parallel or substantially parallel to each other and are, typically, concentrically or substantially concentrically disposed relative to each other.

However, the respective endless conductors 12 could be offset relative to each other, 15 may not be parallel or substantially parallel to each other, and may not be concentrically positioned. I The light emitting devices 14 include light emitting diodes 22 (LED). LEDs are advantageous since they consume approximately twenty times less power than 20 ordinary filament type bulbs, produce less heat, have a life span many times longer than that of an ordinary filament bulb, and only require a low voltage power supply to operate. 1 Each light emitting device 14 also includes a protective housing 24 in which '

each LED 22 is received. The housing 24 is then fastened to each respective endless conductor 12 so that the housing 24 spans therebetween.

Each group of light emitting devices 14 associated with the first, second and 5 third sets of the endless conductors 12 emit light of first, second and third colours, respectively. The first, second and third colours are, in this embodiment, the same colour, but may be of different colours. In the case when the first, second and third colours are each different, the colours are preferably the primary colours red, blue and green so that, in use, white light can be produced.

The lighting device 10 also comprises means for supporting each set of the endless conductors 12, and means for supplying electrical power to the endless conductors 12.

IS The supporting means includes a base 26 and a plurality of sets of elongate support conductors 28, being in this case three sets, which project from the base 26.

Each set of elongate support conductors 28 supports, in direct contact, only one of the endless conductors 12 of each of the sets of endless conductors 12. It is beneficial that the outer endless conductor 20 of the set of endless conductors 12 is supported by the 20 support conductors 28.

The support conductors 28 are formed from an electrically conductive material, which is typically the same material that the endless conductors 12 are formed from. The support conductors 28, similarly to the endless conductors 12, are

also unshielded. The endless conductors 12 and the support conductors 28 are thus in electrical communication with each other. Since the material of the endless conductors 12 and support conductors 28 is metal, they can be attached to each other by, for example, spot welding or soldering.

The electrical power supply means includes a plurality of batteries (not shown), typically between two and four depending on the length of time the lighting device 10 is expected to operate on a single charge. The batteries can be of any suitable size and type and, in this case, each is an 'AA' size Ni-MH battery supplying 10 a DC current and rated at 1.2 volts. The batteries are held in the base 26, which has a removable bottom cover 30 to allow insertion and removal.

The batteries are rechargeable. To facilitate convenient recharging, a recharging device (not shown) is incorporated into the base 26. The recharging device 15 operates in 'fast charge mode', which allows the batteries to be recharged in around one hour. However, the recharging device could be separate from the base 26, and could operate in a 'slowcharge' mode.

The electrical power supply means also includes a, typically conventional, 20 shielded conductor 32, which runs from each endless conductor 12 not directly supported by the support conductors 28 to the base 26, a disconnectable electrical connection (not shown) to the mains power supply, and a current control circuit (not I shown). Each shielded conductor 32 is attached in electrical communication to the I

respective inner endless conductor 18, and is unobtrusively positioned to run along the surface of an associated support conductor 28 and into the base 26.

The disconnectable electrical connection is used to electrically energise the 5 recharging device via a conventional input socket (not shown) in the side of the base 26. The disconnectable electrical connection typically incorporates a step-down transformer and AC/DC converter, so that its output is typically at 9 volts DC.

The current control circuit includes a software updateable microprocessor, a 10 solid-state drive circuit, a current sense circuit and a voltage supply sense circuit to control or regulate the flow of current which is produced by the batteries and input by the disconnectable electrical connection. The current control circuit controls the current so that it is output as pulsed current. Pulsing the current helps to regulate the operating temperature of the LEDs 22, increase the lifespan of the LEDs 22, and 15 increase the duration of operation of the lighting device 10 from a single charge.

Since the shielded conductor 32 is connected to the inner endless conductor 18 of the set of endless conductors 12, induced electromagnetic radiation will primarily occur between the inner and outer endless conductors 12. The unshielded outer 20 endless conductors 12 and support conductors 28 thus form a radiation shield.

The electrical power supply means is in electrical communication with the support conductors 28 projecting from the base 26. A circuit is thus created by the batteries, the current control circuit, the shielded conductors 32, the light emitting

devices 14, the endless conductors 12, and the support conductors 28. The LEDs 22 of the light emitting devices 14 are consequently illuminated when the circuit is closed. 5 The lighting device 10 also incorporates one or more controllers (not shown) by which the LEDs 22 can he selectively turned ON and OFF, and/or by which the LEDs 22 can be selectively dimmed. These controllers are preferably accessibly positioned on the base 26 and are incorporated as part of the current control circuit.

10 When the lighting device 10 is in use, the microprocessor of the current control circuit monitors the pulsed current being supplied to the LEDs 22 through the solid-state drive circuit and, based on feedback received from the current sense circuit and voltage supply circuit, adjusts the pulsed current accordingly to maintain the required level of illumination set via the controllers.

The circuit is preferably arranged so that the exposed support conductors 28 and the endless conductors 12 act as the return or negative side of the circuit which, in use, is at 0 volts, and the shielded conductors 32 act as the positive side of the circuit.

20 An electronically operated short circuit or trip device (not shown), typically incorporated as part of the solid state drivers of the current control circuit, is used to prevent damage to the lighting device 10 should current overload occur.

The disconnectable electrical connection may also he connectable in the circuit

to energise the LEDs 22 while simultaneously energising the recharging device to recharge the batteries.

By mounting the light emitting devices 14 on the endless conductors 12, the 5 endless conductors 12 act as efficient thermally conducting heat sinks for the LEDs 22. When used in conjunction with a pulsed power supply, LEDs 22 having a higher power rating can be utilised without impacting the expected operational life of the LED 22.

10 Even when using higher power rated LEDs, the expected power consumption when using, for example, nine LEDs is 0.5 watts. This is far less than the power consumption of a single standard filament bulb.

More of less than three separate set of the endless conductors 12 may of course 15 be provided.

Depending on how the light emitting devices are to be arranged, it is possible to provide endless conductors in sets of three or more, and to provide any suitable number of the light emitting devices. The light emitting devices of a set of endless 20 conductors could also emit different coloured light.

The light emitting devices may also be selectively positionable. In this case, the light emitting devices may be releasably fastenable to the endless conductors, for example by clip means.

Although the lighting device has been described with reference to the conductors 12 being endless so that each conductor 12 forms a loop, the conductors 12 may not necessarily be joined end-to-end and therefore would only be substantially a 5 loop.

It is thus possible to provide a standalone solid-state lighting device having components with a longer expected operational life and which can operate for long periods on a single charge. It is also possible to provide a lighting device which has 10 non-hazardous unshielded electrical conductors, remains relatively cool during operation, and does not pollute its surroundings with deposited material or undesirable radiation. The embodiment described above is given by way of example only and various 15 modifications will be apparent lo persons skilled in the art without departing from the scope of the present invention as defined by the appended claims. For example, the lighting device could take the form of a standard lamp or ceiling light.

Claims

( 10 CLAIMS

1. A lighting device comprising a set of spaced conductors, each of which is looped or substantially looped, at least one light emitting device held by, and in 5 electrical communication with, the spaced conductors, means for supporting the spaced conductors, and means for supplying electrical power to the spaced conductors to electrically energise the light emitting device(s).

2. A lighting device as claimed in claim 1, wherein each spaced conductor is 1 0 unshielded 3. A lighting device as claimed in claim I or claim 2, wherein each spaced conductor is in the form of a rigid or substantially rigid wire.

15 4. A lighting device as claimed in any one of the preceding claims, wherein each spaced conductor is an endless conductor.

5. A lighting device as claimed in any one of the preceding claims, wherein two or more sets of the spaced conductors are provided.

6. A light emitting device as claimed in claim 5, wherein the at least one light emitting device of each set of the spaced conductors emits light of a different colour from the other light emitting devices.

7. A lighting device as claimed in any one of the preceding claims, wherein the spaced conductors of the or each set are formed into the same or substantially the same shape.

5 8. A lighting device as claimed in claim 7, wherein the said shape is annular or substantially annular.

9. A lighting device as claimed in claim 6. wherein the said shape is polygonal or substantially polygonal.

10. A lighting device as claimed in any one of claims 7 to 9, wherein the spaced conductors of the or each set are concentrically positioned relative to each other.

11. A lighting device as claimed in any one of the preceding claims, wherein the 15 said at least one light emitting device includes a light emitting diode (LED).

12. A lighting device as claimed in any one of the preceding claims, wherein a plurality of the said light emitting devices are held by, and electrically connected to, the or each set of spaced conductors.

13. A lighting device as claimed in any one of the preceding claims, wherein the I support means includes a base and a set of elongate support conductors projecting from the base and associated with the or each set of spaced conductors, the support conductors of the or each set of support conductors being attached to only one of the

spaced conductors of the or each respective set of spaced conductors and being in electrical communication with both of the spaced conductors of the or each said respective set of spaced conductors.

S 14. A lighting device as claimed in claim 13, wherein each elongate support conductor is in the form of a rigid or substantially rigid wire.

l5. A lighting device as claimed in claim l3 or claim 14, wherein the power supply means is in the form of one or more batteries electrically connectable to the 10 support conductors.

16. A lighting device as claimed in claim 15, wherein the one or more batteries are positionable in the said base.

IS 17. A lighting device as claimed in claim 15 or claim l6, wherein the one or more batteries are rechargeable.

18. A lighting device as claimed in claim 17, wherein the power supply means includes a battery recharging device.

19. A lighting device as claimed in claim 18, wherein the battery recharging device is incorporated into the said base.

20. A lighting device as claimed in any one of the preceding claims, wherein the

power supply means includes a disconnectable electrical connection to the mains power supply by which the light emitting device(s) can be energised.

21. A lighting device as claimed in claim 20 when dependent on claim 19, wherein 5 the electrical connection to the main power supply in use energises the battery recharging device.

22. A lighting device as claimed in any one of the preceding claims, wherein the power supply means includes a current control circuit having an in use pulsed current 1 U output.

23. A lighting device as claimed in claim 22, wherein the current control circuit includes a software-updateable microprocessor which, in use, monitors the pulsed current output.

24. A lighting device as claimed in any one of the preceding claims, wherein the lighting device is a table lamp.

25. A lighting device substantially as hereinbefore described with reference to the 20 accompanying drawings.