GB2333829A

GB2333829A - Electroluminescent interior vehicle lighting

Info

Publication number: GB2333829A
Application number: GB9801985A
Authority: GB
Inventors: Adrian Trevor Iles
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-01-31
Filing date: 1998-01-31
Publication date: 1999-08-04
Also published as: GB9801985D0

Abstract

Within a motor vehicle so-called "mood" or environmental light is provided by electroluminescent panels 9. These panels 9 are generally located above seating 6 within the motor vehicle in order to present diffuse illumination without significant reflection of said illumination against window 3, 4, 5 surfaces of the motor vehicle. The panel means 9 may comprise a plurality of individually operable elements which may create different colours and therefore different styling within the motor vehicle as required.

Description

AN INTERIOR LIGHTING ARRANGEMENT The present invention relates to an interior lighting arrangement and more particularly to a lighting arrangement for use within a motor vehicle.

There is an eternal requirement to stylise motor vehicles to make them more distinctive within the market place and to meet motorists' tastes.

Traditionally, interior lighting within a motor vehicle has comprised a relatively bright bulb located within a trim housing such that the bulb is illuminated upon opening the door and/or when specifically switched on.

Such illumination allows the driver to prepare to embark upon a journey, ie. insert the ignition key or, when parked, perform such acts as review a map, etc. Unfortunately, being a point source, a light bulb has a relatively high intensity and so precipitates too much reflective glare for use whilst driving the vehicle. It will be appreciated that glare can diminish the range of observation and provide distraction to the driver. Furthermore, generally it is not clear illumination that is required within a motor vehicle to provide the necessary styling for motorists tastes; a dull diffuse background illumination would provide the desired "mood".

It is an object of the present invention to provide an interior lighting arrangement for a motor vehicle which substantially allows provision of diffuse mood lighting within a motor vehicle without significant glare reflection from window surfaces of that vehicle.

In accordance with the present invention, there is provided an interior lighting arrangement for a motor vehicle, the arrangement comprising electroluminescent panel means distributed within the motor vehicle, said electroluminescent panel means being configured to present diffuse illumination within that motor vehicle without significant reflection of said illumination from any window surfaces of the vehicle and so raise ambient light intensity within the motor vehicle without glare distraction in use to any of the occupants thereof.

The panel means is preferably located above seating within the motor vehicle.

The panel means may comprise individual panel elements and furthermore these individual elements may be separately operable to achieve differential illumination for aesthetic or functional reasons.

The panel means may be able to present different coloured light within the motor vehicle The lighting arrangement may include shuttering to allow more controlled illumination within the motor vehicle. Furthermore, the panel means may be associated with a point light source or greater intensity element which is independently operable when required by an occupant of a motor vehicle.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing, in which a schematic representation of a motor vehicle interior is depicted with an illumination arrangement.

Referring to the drawing illustrating a motor vehicle interior, it will be noted that the motor vehicle interior includes a roof 1, a side panel 2 and window/windscreen elements 3, 4, 5 along with seating 6. Such an arrangement for a motor vehicle interior is common. Typically, above a rear view mirror 7 there is located an interior light 8 which is operated when the doors of the vehicle are opened or upon specific switching by a motor vehicle occupant. As indicated above, the provision of such a intense light source able to provide sufficient illumination within the motor vehicle can create glare problems by reflection against the window/windscreen 3, 4, 5 glass.

Furthermore, "clarity" illumination may not be the objective where styling of a motor vehicle is required.

In the present invention, illumination panels 9 are located within the motor vehicle interior normally in the roof lining and adjacent seating 6.

Thus, the panels 9 present a diffuse rather than concentrated point light source with an evident reductidn in occupant distraction and glare. The panels 9 are made from an electroluminescent assembly. In such electroluminescent panels 9, a solid state phenomenon in which semiconductor crystals (phosphorous) is used to generate light from presented electrical energy. The conversion process has a relatively high efficiency and so there is little power drain within the motor vehicle and temperature elevation is generally insignificant. Such factors are important within a modern motor vehicle where there are already existing high demands upon the electrical system. A known supplier of electroluminescent panels is Danielson Limited of Aylesbury, England under their trade mark "Quantaflex Micro". These electroluminescent panels can be quite thin and in the order of 0.3 mm, thus, non-intrusive accommodation within a motor vehicle cabin is easily achieved.

The construction of the Quantaflex (TM) electroluminescent panel is described by Danielson as a distribution of phosphor pigments through a non-hydgroscopic layer of dielectric material. This layer of dielectric material is then sandwiched between two conductive layers or electrodes.

Typically, the upper electrode is manufactured from a clear polyester film which has a sputter coated indium tin oxide (ITO) electrode, whilst the lower polyester layer is printed with a conductive silver ink. When an alternating current of a predetermined voltage and frequency is connected across these electrodes in respective upper and lower polyester layers, a charge is induced within the dielectric layer exciting the phosphor particles to the point where they omit energy in the form of light. The colour of light is determined by appropriate doping of the phosphor particles with trace elements. An alternative title for an electroluminescent lamp or panel is a light-emitting capacitor (LEC). Normally the panel is completed by laminating a polyester layer onto the back of the electrode layers, however, and as indicated above, the total thickness of the panel may be less than 0.3 mm. For further information with regard to electroluminescent panels, the person skilled in the art is directed to appropriate text books and data sheets readily available from manufacturers.

Within the motor vehicle interior depicted in the drawing it will be noted that the panels 9 are generally located above seating 6 and present a diffuse light source to the occupants of the associated seating 6 therebelow.

However, it will be understood that a single panel could be provided for substantially the entire roof surface of the motor vehicle interior.

Alternatively, a large number of panels could be provided with individual colour responses through phosphor doping under electrical/frequency excitation in order to give differing interior styling/patterning. Thus, individual panels could be operable within the motor vehicle interior to adapt that vehicle interior roof and/or any other surfaces incorporating the electroluminescent panelling and as required by the occupant. Such an arrangement would allow the occupant to personalise his motor vehicle in comparison with others. Furthermore, a note or notice panel could be provided within the vehicle such that the occupant is reminded of some fact or requirement, eg. the note panel could include a clip to secure a sheet of paper such that when the occupant needed reminding the electroluminescent panel illuminated that sheet of paper and so the message thereon.

The roof lining or head liner within a motor vehicle will typically be made from a moulded laminate construction including cloth, foam and glass fibre along with adhesive to hold the laminate together. In accordance with the present invention in a preferred embodiment, the illumination panel would be located during assembly within this moulded head liner. Thus, the panel 9 will be secured behind the generally decorative material cover of the head liner and the more robust structural components of that liner.

Thus, the decorative cover which is normally a fabric should be sufficiently thin such that there is only a controllable degree of attenuation in the illumination from the panel 9. Normally, the decorative surface fabric adhered to a motor vehicle roof liner will have a denier of 55 Decitex.

Although electroluminescent panels have been used widely as signage devices, it will be understood by those skilled in the art that the relatively low intensity does not lead to wide usage for general illumination purposes.

However, as indicated above, in accordance with the present invention, the objective is to provide so-called mood or background lighting within a motor vehicle in order to enhance the driving environment and styling of that motor vehicle. Electroluminescent panels achieve such diffuse illumination with low weight, thickness and power consumption quotients. Furthermore, it will be appreciated by appropriate stacking of several layers of electroluminescent panelling and in particular by using primary colours, it may be possible to create a wide range of colours within the motor vehicle interior. Furthermore, it may be possible to incorporate within one of these layers of electroluminescent panelling a sign, such as a seat belt reminder, which could be applicable to each seat within the motor vehicle and operated as required. Similarly, signalling to the driver could be indicated through a colour change that a door is open or a window has been left slightly ajar on leaving the vehicle.

It will be appreciated by those skilled in the art that it is also possible to arrange a multiplicity of panels 9 such that relative tilting between panels and with respect to the motor vehicle can be achieved in order to orient the light arrangement therein. Furthermore, such electroluminescent panels may be presented in a louvre style format or include shuttering or means for distinct panel operation and thus sectional illumination as required.

As indicated previously, typically the electroluminescent panel in accordance with the present invention will be covered with a fabric as part of the roof liner of the motor vehicle. This fabric may be stuck to the electroluminescent panel or stretched over it. However, it will be appreciated that the relatively low heat generation of electroluminescent panels should not present any detrimental heat or safety considerations in comparison with normal evacuated tungsten bulb illumination.

In order to provide enhanced illumination when required, it will be appreciated that more traditional, relatively high-intensity light illumination may be provided through a tungsten bulb arrangement associated with the electroluminescent panel. This high intensity light source would be independently operable when required. Thus, each panel 9 will typically be provided with a switch 10 at a convenient location for an occupant of the seat associated with a panel 9 to operate either the panel 9 alone or any associated high intensity light for reading or other activity.

It will be appreciated by those skilled in the art that the relatively flat illumine scent panels are bonded into the head liner panel prior to application of the fabric cover. Thus, care must be made to correctly orientate the panels 9 appropriately within that head liner panel assembly to achieve the necessary performance and power/control wiring for operation thereof.

As indicated above, it is necessary for operation of the electroluminescent panels 9 to provide preferably a sinusoidal alternating power source and so a DC to AC invertor unit is required. This invertor unit will normally be located within a parcel shelf or behind the facia panel of the motor vehicle. It will be appreciated that the panels being light and thin do not significantly alter the weight distribution within a motor vehicle and so considerations with regard to the centre of gravity for stability purposes.

Claims

CLAIMS 1. An interior lighting arrangement for a motor vehicle, the arrangement comprising electroluminescent panel means arranged about the interior of the motor vehicle, said electroluminescent panel means being configured to present diffused illumination within that vehicle without significant reflection of said illumination from any window surfaces of the vehicle and so raise ambient light intensity within the motor vehicle without glare distraction in use to any occupant thereof.
2. An arrangement as claimed in Claim 1, wherein the panel means is located adjacent and above seating within the motor vehicle.
3. An arrangement as claimed in Claim 1 or Claim 2, wherein the panel means comprises a plurality of individual panel elements.
4. An arrangement as claimed in Claim 3, wherein said individual panel elements are separately operable.
5. An arrangement as claimed in Claim 3 or Claim 4, wherein said individual panel elements are arranged to provide different colours of illumination.
6. An arrangement as claimed in any preceding claim, wherein said arrangement is associated with shutter means to allow a proportion of said electroluminescent panel means to be shuttered from illuminating said interior of said motor vehicle.
7. An arrangement as claimed in any preceding claim, wherein said arrangement includes a separately operable relatively high-intensity illumination element which will present significant reflection from said window surfaces but allows greater clarity illumination within the motor vehicle.