GB2528250A

GB2528250A - Lighting apparatus

Info

Publication number: GB2528250A
Application number: GB1412432.5A
Authority: GB
Inventors: Andrew Young
Original assignee: AY CAPITAL Ltd
Current assignee: AY CAPITAL Ltd
Priority date: 2014-07-13
Filing date: 2014-07-13
Publication date: 2016-01-20
Also published as: GB201412432D0

Abstract

A lighting apparatus 1 comprises at least one light emitting diode (LED) 13 and an integral power means wherein the power means comprises a collection means 3 such as an antenna to collect ambient radio frequency (RF) electromagnetic radiation and a converter 9 to convert the RF radiation to DC power. The apparatus may include a storage device such as a battery for storing DC power. The lighting apparatus may be used to illuminate a sign or may be incorporated into a ceiling tile.

Description

Lighting Apparatus The present invention relates to a lighting apparatus and an improved power means for a lighting apparatus.

LED lighting for street lighting, industrial lighting, road/path lighting and illuminated signs are well known. LED lighting is used for improved energy efficiency when compared to conventional lighting means, such as fluorescent or halogen lighting. The improved energy efficiency of LED5 allows for reliable illumination, with a reduced chance of light failure, at a reduced cost and in a more environmentally-friendly manner. As LED technology has developed it is also possible to achieve an increased power rating and an increase in visible light emitted, i.e. increased lumen output.

It is now known to use LED technology for general lighting purposes rather than their use being restricted to decorative or electronic signal uses.

Known LED lighting is commonly powered by a mains power supply.

However, it has been found that connection to the mains is difficult in many of the locations that LED lighting is needed. For example, LED-illuminated warning signs at remote locations, such as cliffs; or where illuminated signs are used to warn of dangers or obstacles. LED lighting is also used for illuminated exits signs, where the exit must be lit even when connection to mains power is lost or unavailable. Thus, a need to provide reliable LED lighting without a mains power supply has been identified.

Furthermore, for illuminated warning signs to be installed conveniently for a temporary use it is often not possible for the lighting to be connected to mains power and a portable sign with an integral power means is highly desirable.

The present invention sets out to provide an improved LED lighting apparatus, which alleviates the problems described above.

In one aspect, the invention provides a lighting apparatus comprising at least one light emitting diode (LED); an integral power means wherein the power means comprises a collection means to collect ambient radio frequency (RE) electromagnetic radiation and a converter to convert the RE radiation to DC power.

The present invention enables the or each LED to be powered without connection to a mains power supply or the provision of a battery. The lighting apparatus, when used with a battery, is effectively "trickle-charged" to be used when required. The present invention allows for the lighting apparatus to be portable and free of external connectors, cables etc. Furthermore, the cost and energy consumption of the lighting apparatus is much reduced so that the lighting can be powered free of charge to the user.

Preferably, the collection means comprises an antenna.

Using an antenna allows the system to be optimised according to the intended use and the power output required. The size and arrangement of the antenna is optimised to increase the DC power that is collected.

Preferably, the collection means automatically collects ambient radio frequency (RE) electromagnetic radiation.

It is understood that the collection means collects ambient electromagnetic radiation with frequency less than about 300GHz.

Preferably, the lighting apparatus produces between about 5 and 50 microwatts of DC power.

The level of power produced by the present invention is sufficient to power an LED for use in applications requiring a low level of light; for example in emergency or warning signs. For example; the present invention has particular application to emergency lighting where the regulations require illumination of 1 lux.

Preferably, the or each LED has a power to lumen output ratio of about 1:80 Lumens per Watt (lm/W) to 1:100 Lumens per Watt (lm/W) Preferably, the lighting apparatus further comprises a storage device for storing DC power.

More preferably, the storage device is a battery.

By storing power, the apparatus is able to power the LED on demand and reserve power in the event that RE radiation cannot be collected.

Preferably, the lighting apparatus further comprises at least one reflective surface.

Reflective surfaces are incorporated into the lighting apparatus of the present invention to direct and maximise the perceived light output from the or each LED.

Preferably, the lighting apparatus comprises one or more flashing LED5.

Flashing LED5 require lower power consumption. In some embodiments of the present invention, a flashing LED is intermittently powered depending on the strength of RF signal available.

Preferably, the lighting apparatus comprises a lens or an arrangement of lenses adjacent to the or each LED.

A lens is used, particularly in emergency or warning lighting applications, to maximise and direct the perceived light output.

Preferably, the LED protrudes from the lighting apparatus such that light is directed to and reflected from one or more surfaces of the apparatus to or in which the LED is mounted.

The arrangement of the surfaces of the light apparatus around the LED can be configured to maximise and direct the perceived light output.

Preferably, the lighting apparatus is mounted in a ceiling tile.

Preferably, the lighting apparatus further comprises a control means.

A control means allows the lighting apparatus to control the power output to the LED so that the desired lighting effect can be achieved.

For the purposes of clarity and a concise description, features are described herein as part of the same or separate embodiments; however it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

within this specification, the term "about" means plus or minus 20°/a, more preferably plus or minus lO%, even more preferably plus or minus 5%, most preferably plus or minus 2%.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings, in which:-Figure 1 is schematic diagram showing the components of the lighting apparatus constructed in accordance with the present invention; Figure 2 is a circuit diagram showing the components of the lighting apparatus shown in Figure 1; Figure 3 is schematic diagram showing the components of lighting apparatus constructed in accordance with a second embodiment of the present invention; Figure 4 is a circuit diagram showing the components of the energy conversion lighting apparatus shown in Figure 3; Figure 5 is a schematic illustration of an emergency lighting apparatus in accordance with an embodiment of the present invention; Figure 6 is a schematic illustration of a road lighting apparatus in accordance with an embodiment of the present invention; and Figure 7 is schematic illustration of a ceiling tile lighting apparatus in accordance with an embodiment of the present invention.

Referring to Figures 1 and 2, the lighting apparatus 1 of the present invention is shown. The lighting apparatus 1 harnesses ambient radio-frequency (RF) electromagnetic radiation to convert the radiation into a DC current, which powers a light emitting diode (LED) 13. Sources of ambient RF radiation include TV/radio transmitters and mobile telephone/cellular base stations. It is envisaged that, in use, multiple LED5 are arranged in a suitable array according to the intended purpose. For example, the LED5 are arranged to illuminate a sign marking a road, an emergency exit, a hazard (i.e. acting as a warning sign); or to provide external lighting to a building, such as a house, industrial unit or car park, including illuminating a multi-storey car park.

The energy conversion apparatus 1 comprises an antenna 3 and a tuner/filter circuit 5. It is envisaged that the antenna 3 is housed within the device, such as a sign, that is to be illuminated. The size of the antenna is pre-determined according to the power required to be collected.

The tuner/filter circuit 5 comprises the primary windings of a transformer coil 7 and a variable capacitor. The tuner/filter circuit 5 is tuned to select a suitable frequency according to the availability and proximity of a suitable radio frequency transmitting source. The antenna 3 receives a carrier wave and modulated signal and the tuner/filter circuit 5 tunes, i.e. filters, the received signal to achieve the maximum possible signal. The filtered signal is transferred to the secondary winding of the transformer coil 7.

The secondary winding of the transformer coil 7 is configured as a separate, tuned circuit to allow for any variation in the components of the above-described system, particularly allowing for the capacitors. This ensures that the maximum voltage is available to be input to the rectifier diodes 11 within a multiplier circuit 9. The rectifier diodes 11 have a low forward voltage, which minimises the voltage loss and ensures that the maximum voltage is available to the high-efficiency light emitted diode (LED) 13.

As shown in Figure 2, a capacitor is used to store charge and allows for a larger LED array to be powered, if required. In alternative embodiments of the present invention, charge is stored in a battery unit until power is required by the LED.

In a preferred embodiment, it is envisaged that the LED 13 is powered constantly; or in alternative embodiments the LED 13 is powered intermittently so that the LED flashes; or a combination of constant and flashing LED5 can be achieved.

In an alternative embodiment, the lighting apparatus comprises an array of flashing LED5. This allows for lighting to be provided intermittently; for example in applications such as emergency or warning lights. If there is insufficient RE signal the LED will not be constantly powered but will remain off until sufficient RE radiation has been collected to provide power to the flashing LED5. Once all available power has been consumed by the flashing LED5 the lighting apparatus will switch off and the process of collecting RE energy will resume until, as before, sufficient RE radiation is collected.

Referring to Figures 3 and 4, in an alternative embodiment of the present invention the energy conversion lighting apparatus 21 further comprises a full-wave rectifier 29. The full-wave rectifier 29 ensures that the lighting apparatus converts energy from ambient RF radiation into power during both the positive and negative oscillation of the wave, i.e. to achieve a higher output voltage.

Referring to Figure 3, the lighting apparatus 21 comprises an antenna 23 and a tuner/filter circuit 25. The tuner/filter circuit 25 comprises the primary winding of a transformer coil 27 and a variable capacitor. The tuner/filter circuit 25 is tuned to select a suitable frequency according to the availability and proximity of a suitable radio frequency transmitting source. The antenna 23 receives a carrier wave and modulated signal. The tuner/filter circuit 25 tunes, i.e. filters, the received signal to achieve the maximum possible signal. The filtered signal is transferred to the secondary winding of the transformer coil 27.

As shown in Figure 4, the secondary windings of the transformer coil 27 are connected in series with a centre-tapped secondary winding to enable full-wave rectification using the minimum possible number of components.

Each of the two secondary windings of the transformer coil 27 is configured as a separate tuned circuit to allow for variation in the components of the system and to enable the maximum possible voltage to be available to the rectifier diodes 31. The rectifier diodes 31 have a low forward voltage, which minimises the voltage loss and ensures that maximum voltage is available to the high-efficiency light emitted diode (LED) 33.

In preferred embodiments of the present invention, the LED 13, 33 is powered solely by the radio frequency radiation harnessed by the apparatus 1, 21 and no further power supply is needed.

The visibility of the light emitted from the diode/s 13 is increased by the use of suitable reflective surfaces surrounding the or each LED. The use of angled and shaped reflective surfaces in the arrangement of the lighting apparatus is configured according to a user's requirements.

Referring to Figures 5, 6, and 7 specific applications of the present invention are described.

Figure 5 illustrates the application of the present invention to emergency lighting, showing a "running man" emergency exit light. The sign 50 comprises a coloured frame Sla and a "running man" symbol Sib. An LED 52 is mounted at one corner of the sign 50 and protrudes from the outer surface of the sign 51. The surface of the sign is angled to reflect light from the LED 52 and illuminate the symbol 51. An RF antenna 53 is wound and mounted at the rear of the sign. In use, the antenna 53 harnesses ambient radio-frequency (RE) electromagnetic radiation, which is converted into a DC current, which powers the LED 52. It is possible to harvest power from ambient RF radiation at levels of between about 5 to microwatts. The LED 52 incorporated into the lighting apparatus has a power to lumen output ratio of about 1:80 Lumens per Watt (lm/W) to 1:100 Lumens per Watt (lm/W). Light from the LED 52 is emitted to satisfy the minimum illumination requirements for emergency signs of about 1 lux.

Referring to Figure 6, in a further embodiment of the present invention the lighting apparatus of the present invention is used to illuminate a sign to be fixed to the central reservation barrier of a major road, such as a motorway. A reflective, mirrored strip 61 is attached to the central reservation and a single LED 62 is positioned at one end. The LED 62 protrudes from the mirrored strip 61 and is mounted at an angle to the planar surface of the mirrored strip 61. The planar surface of the mirrored strip 61 is also sloping away from the protruding LED 62. An RE antenna 63 is wound and mounted at the rear of the body of the sign 60. In use, the antenna 63 harnesses ambient RE radiation, which is converted into a DC current to power the LED 62. Light emitted from the LED 62 is reflected from the surface of the mirrored strip 61 to maximise the illumination of the barrier.

Referring to Figure 7, in a further embodiment of the present invention the lighting apparatus of the present invention is used for domestic, office or industrial lighting, by incorporating the invention into a ceiling tile 70.

In the embodiment shown in Figure 7, the ceiling tile 70 is used as a replacement for emergency exit lighting in offices and eliminates the need for emergency lighting to be powered by a permanent live power feed and a battery back-up. The size of the ceiling tile 70 is 2ft by 2ft, or about 30.48 cm by 30.48 cm. The lighting apparatus is integral with the ceiling tile 70 and provides the required level of light when positioned in front of exits or along a path to an emergency exit.

A single LED 71 is mounted at the centre of the ceiling tile 70. The LED 71 is mounted adjacent to or co-axially with a lens 72, with the lens 72 on the room-facing/inward face 71a of the ceiling tile 70. Both the LED 71 and the lens 72 are mounted within an aperture in the ceiling tile. The LED 71 is powered by ambient radiofrequency (RF) radiation, which is collected by a flat RF antenna 73 coiled on the ceiling-facing/outward face 70b of the ceiling tile 70. In use, the antenna 53 harnesses ambient radio-frequency (RE) electromagnetic radiation, which is converted into a DC current to power the LED 71. A controller 75 is also mounted on the ceiling-facing/outward face 70b of the ceiling tile 70. The antenna 73 and the controller 75 are both mounted within the confines of the perimeter of the ceiling tile 70, such that the ceiling tile can be retro-fitted to easily and conveniently replace an existing tile. Thus, emergency lighting can be provided without any additional wiring, for example to the main power supply.

In a further embodiment, a battery is also mounted on the ceiling-facing/outward face of the ceiling tile and is trickle-charged by conversion of the collected RE radiation. The controller 75 determines whether collected RF radiation is used to directly power the LED or trickle charge the battery. Any power stored in the battery is used, as required, when insufficient R.F radiation is available to power the LED. Use a back-up battery ensures there is no interruption to power delivered to the LED The above described embodiment has been given by way of example only, and the skilled reader will naturally appreciate that many variations could be made thereto without departing from the scope of the claims.

Claims

Claims 1. A lighting apparatus comprising at least one light emitting diode (LED); an integral power means wherein the power means comprises a collection means to collect ambient radio frequency (RF) electromagnetic radiation and a converter to convert the RF radiation to DC power.
2. A lighting apparatus according to claim 1 wherein the collection means comprises an antenna.
3. A light apparatus according to claim 1 or claim 2 wherein the collection means automatically collects ambient RF electromagnetic radiation.
4. A lighting apparatus according to any preceding claim wherein the collection means collects ambient electromagnetic radiation with frequency less than about 300GHz.
5. A lighting apparatus according to any preceding claim wherein the lighting apparatus produces between about 5 and 50 microwatts of DC power.
6. A lighting apparatus according to any preceding claim wherein the or each LED has a power to lumen output ratio of between about 1:80 Lumens per Watt (lm/W) to 1:100 Lumens per Watt (lm/W).
7. A lighting apparatus according to any preceding claim wherein the lighting apparatus further comprises a storage device for storing DC power.
8. A lighting apparatus according to claim 7 wherein the storage device is a battery.
9. A lighting apparatus according to any preceding claim further comprising at least one reflective surface.
10. A lighting apparatus according to any preceding claim wherein the lighting apparatus comprises one or more flashing LED5.
11. A lighting apparatus according to any preceding claim comprising a lens or an arrangement of lenses adjacent to the or each LED.
12. A lighting apparatus according to any preceding claim wherein the LED protrudes from the lighting apparatus such that light is directed to and reflected from one or more surfaces of the apparatus to or in which the LED is mounted.
13. A lighting apparatus according to any preceding claim mounted in a ceiling tile.
14. A lighting apparatus according to any preceding claim further comprising a control means.
15. A lighting apparatus substantially as hereinbefore described or referred to in Figures 1 to 7.