GB2331616A - Illumination means for illuminating a display - Google Patents

Abstract

Illumination means for providing backlight for an advertising display for example on a transport vehicle, comprises an encapsulated laminate panel (1) including a layer of electroluminescent material (2). The material (2) is connected in an electrical circuit which includes an inverter and power is supplied to the circuit from the electrical system of the vehicle. The laminate panel preferably comprises a fluted support layer (14) of polypropylene, fluid barrier layer (12) of polyester, a desiccant material layer (10), a phosphor based electroluminescent layer (2), a further fluid barrier layer (8), a translucent PVC layer (6) coated with translucent white ink, and a protection layer (4) of polymeric vinyl film.

Description

1 ILLUMINATION 14EARS rOR ILLUMINATING A DISPLAY 2331616 The present

invention relates to illumination means for illuminating a display and, more particularly, to illuminating means for providing back lighting for a display. The invention also relates to apparatus for controlling operation of the illuminating means.

The outside panels of transport vehicles are commonly used to display advertising images. This involves the use of a variety of modes of transport and includes buses, trains, freight lorries, delivery vans, taxis and trams. A common way to increase the visibility, effectiveness and impact of advertising images is by the illumination of the advertising. The use of illuminated panels has a commercial advantage for an advertiser in that the images are visible at night or in low light conditions.

The usual method of illuminating images uses standard methods such as fluorescent tubes. Using standard techniques to illuminate transport vehicle advertising images has a number of disadvantages. The fluorescent tubes are vulnerable to mechanical damage, to the effects of the weather and to the vibrations caused by the movement of the vehicle and from the engine of the vehicle. In addition, provision of fluorescent tubes usually increases the dimensions of the vehicle.

The present invention provides a reliable method of illuminating advertising images on the outside of transport vehicles that does not 2 substantially increase the dimensions of the vehicle and overcomes the other disadvantages of the standard methods mentioned above.

According to a first aspect of the present invention there is provided illumination means for illuminating a display, the illumination means comprising a laminate panel including a layer of electrolumines cent material and means for supplying electric power to actuate the material, the arrangement being such that, in use, the illumination means provides back light for the display.

Preferably the laminate panel comprises a first fluid barrier layer adjacent the layer of electroluminescent material.

It is also preferable that the laminate panel comprises a layer of desiccant material arranged such that the layer of electrolumines cent material lies between the first fluid barrier layer and the layer of desiccant material.

The laminate panel preferably comprises a second fluid barrier layer adjacent the layer of desiccant material. Preferably adjacent the second fluid barrier layer there is a support layer formed with fluting. The support layer is preferably a polypropylene material.

Also adjacent the first fluid barrier layer there is preferably a substantially translucent layer and preferably adjacent the substantially translucent layer there is a layer providing mechanical protection for the laminate panel. The substantially translucent layer is preferably a PVC material having a translucent white ink printed 3 thereon and the layer providing mechanical protection is preferably a calendered polymeric vinyl film.

Preferably the fluid barrier layers are a polyester material.

Preferably the elctroluminescent material is a phosphor based material.

The illuminating means may comprise a plurality of said laminate panels.

According to a second aspect of the present invention there is provided apparatus for controlling operation of illumination means according to the first aspect of the present invention including means for providing alternating current to the layer of electroluminescent material.

Preferably the means for electronic inverting means.

providing alternating current comprises The apparatus may include a plurality of laminate panels and a plurality of electronic inverting means and each panel is powered by a corresponding electronic inverting means.

Each of the electronic inverting means may be provided with a heatsink.

Voltage supplied to the electroluminescent material is preferably in the range of 110 volts to 150 volts and is preferably at a frequency of between 400 Hz and 600 Hz.

4 Preferably output of the or each electronic inverter means adjustable.

is The invention may be put into practice in various ways, however, an embodiment will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is an elevation of a double-decker bus provided with an advertising panel incorporating an embodiment of illuminating means in accordance with the present invention, Figure 2 is a diagra mma tic representation of part of an embodiment of apparatus incorporating the illuminating means, Figure 3 is a cross-section on the line A-A of Figure 2, and Figure 4 is a diagram Of an electrical circuit including the illuminating means.

Referring now to the drawings, there is shown a laminate panel 1 fitted into an advertising frame on the outside of a vehicle 3, such as a bus, or attached directly to the vehicle skin. An advertising image is printed on clear plastic film and is laid over the laminate panel 1 such that, in use, the panel provides backlight.

The vehicle 3 would probably be provided with a plurality of laminate panels 1, for example one on each side of the vehicle 3, and each laminate panel 1 comprises a layer of electroluminescent material (EL) 2 which provides the illumination. Electrolumines cent material is widely used in the electronics industry for providing backlight illumination for instrumentation displays, clocks, watches and other products. The material is a phosphor based substance and light is generated by the application of an alternating current to the substance.

A characteristic of EL material is that light is emitted evenly across the whole surface of the material, so eliminating effects such as 'hotspots' and flicker, which are characteristics of fluorescent tubes.

Each laminate panel 1 comprises a plurality of layers which are encapsulated as follows:- a mechanical protection layer 4 of a depth of approximately 0.3 mm, which provides protection for the other layers; a translucent layer 6 of a depth of approximately 0.25 mm comprising a polyvinyl chloride (PVC) film having a coating of white ink; a first fluid barrier layer 8 of a depth of approximately 0.025 of substantially water resistant polyester material; a layer of elctroluminescent material 2 of a depth of approximately 0.25 mm; a layer of desiccant material 10 of a depth of approximately 1.5 mm, to remove moisture; 6 a second fluid barrier layer 12 of a depth of approximately 0.025 m of substantially water resistant polyester material; and a fluted layer 14 of a depth of approximately 3 mm polypropylene.

The arrangement is such that, when the EL material 2 is excited, light is emitted from the EL material 2 substantially in the direction of the arrow 15.

The protection layer 4 is calendered polymeric vinyl film. The coating of white ink is applied to the surface of the translucent layer 6 by a printing process.

The light output from the EL material 2 is white. When the EL material 2 is not powered (and therefore not illuminating) it has a pink appearance. Therefore, the PVC layer 6 of the panel 1 is printed with translucent white ink in order to mark this.

The laminate panel 1 is connected to a control system 16 comprising a power source 18 and an electronic inverter 20 for supplying AC power to the EL material 2.

If a plurality of laminate panels 1 are provided, the EL material 2 of the panels 1 is powered by a series of inverters 20, one per panel 1. The inverters 20 are mounted, together with heatsinks, (not shown) in suitable positions inside the vehicle 3. Each inverter 20 is connected by a conductor 22 to a corresponding laminate panel 1 on the outside of 7 the vehicle 3. The voltage supplied to the panels 1 is in the range 11OV 150V at a frequency of 400 Hz - 600 Hz. On installation, the inverter output to each panel 1 is adjusted until all of the panels 1 illuminate at the same brightness.

The inverters 20 are connected to the negative terminal 23 of a 24 volt DC battery 24. The positive terminal 25 of the battery 24 is connected to the inverters 20 via two relays 26,28. Relay 26 is connected to an alternator 29. The relay 26 operates when the alternator 29 is in the charging mode.

The relay 28 connects relay 26 to the positive terminal of the inverter 20. The relay 28 operates when the headlights 30 of the vehicle 3 are switched on. The battery 24, relays 26,28 and inverters 20 are connected together using a DC feed cable 32 rated to 30 amps at 24 volts DC.

The conductor 22 connecting each inverter 20 to each laminate panel 1 is a multicore cable rated to 500 volts AC. Output from each inverter 20 is approximately 115 volts at 400 Hz AC.

8

Claims (1)

1. Illumination means for illuminating a display, the illumination means comprising a laminate panel including a layer of electroluminescent material and means for supplying electric power to activate the material, the arrangement being such that, in use, the illumination means provides back light for the display.

   2. Illumination means according to claim 1 wherein the laminate panel comprises a first fluid barrier layer adjacent the electroluminescent material.

   3. Illumination means according to claim 2 wherein the laminate panel comprises a layer of desiccant material arranged such that the layer of electrolumines cent material lies between the first fluid barrier layer and the layer of desiccant material.

   Illumination means according to claim 3 wherein the laminate panel comprises a second fluid barrier layer adjacent the layer of desiccant material.

   5.

   Illumination means according to claim 4 wherein adjacent the second fluid barrier layer there is a support layer formed with f luting.

   6. Illumination means according to claim 5 wherein the support layer is a polypropylene material.

   9 Illumination means according to any one of claims 2 to 6 wherein adjacent the first fluid barrier layer there is a substantially translucent layer.

   8. Illumination means according to any one of claims 6 or claim 7 wherein the substantially translucent layer is a PVC material having a translucent white ink printed thereon.

   9. Illumination means according to claim 7 or claim 8 wherein adjacent the substantially translucent layer there is a layer providing mechanical protection for the laminate panel.

   10. Illumination means according to claim 9 wherein the layer providing the mechanical protection is a calendered polymeric vinyl film.

   11. Illumination means according to any one of claims 4 to 10 wherein the fluid barrier layers are a polyester material.

   12. Illumination means according to any one of the preceding claims wherein the electroluminescent material is a phosphor based material.

   13. Illumination means according to any one of the preceding claims comprising a plurality of said laminate panels.

   Apparatus for controlling operation of illumination means according to any one of the preceding claims including means for providing alternating current to the layer of electrolumines cent material.

   Apparatus according to claim 14 wherein the means for providing alternating current comprises electronic inverting means.

   16. Apparatus according to claim 15 including a plurality of laminate panels and a plurality of electronic inverting means wherein each panel is powered by a corresponding electronic inverting means.

   17. Apparatus according to claim 16 wherein each electronic inverting means is provided with a heatsink.

   18. Apparatus according to any one of claims 14 to 17 wherein voltage supplied to the electroluminescent material is in the range of 110 volts to 150 volts.

   19. Apparatus according to any one of claims 14 to 18 wherein the voltage is at a frequency of between 400 Hz and 600 Hz.

   20. Apparatus according to any one of claims 16 to 19 wherein of the or each electronic inverting means is adjustable.

   Illumination means substantially as reference to the accompanying drawings.

   herein described with 11 22. Apparatus for illuminating vehicle substantially as herein described with accompanying drawings.

   information reference panels to the