ILLUMINATION DEVICE
Field of the Invention
This invention relates to illumination devices, particularly but not exclusively to pressure-activated illumination devices embodied as a decorative or functional article such as a floor covering, a wall hanging, a blanket, an eiderdown or bedspread, or a work of art.
Background to the Invention It is a recognised problem that persons moving around in low light levels, for example at night time or in a darkened room, have a significant risk of falling over or stumbling into things.
For example an elderly person or child trying to get from their bedroom to the bathroom at night, either has to try to find their way in the dark (and run the risk of tripping over things left on the floor, or bumping into items of furniture or such like) or run the risk of disturbing other occupants of the house by switching on the lights. One region of particular concern in a multi-storey house is the stairs between floors, as a fall down the stairs at night could have very serious consequences if the person falling is elderly or frail. To address such problems, it is common for a landing light (i.e. a light in the vicinity of the top of a flight of stairs) to be left on so that anyone moving around at night can clearly see the stairs. It is also common for children to be provided with night lights that may be plugged in and left on throughout the night to provide a low level of light that is sufficient for a child to be able to see what is in their room in the event that they should awaken during the night. Bedside or table lamps are another means by which persons may provide themselves with a light source that is close to hand in the event that they need to move around at night.
A significant problem associated with leaving lights, such as night lights or landing lights, on throughout the night is that the lights waste a significant amount of energy, and incur not insignificant running costs (in terms of the electricity that must be purchased to power the lights). A problem with bedside or table lamps is that they are relatively easy to damage by inadvertently knocking them over as the occupant of the bed, for example, tries to find the light in the night. Another problem is that such bedside or table lights often have on/off switches that are difficult to locate and operate in the dark.
Similar problems can affect users of establishments such as cinemas or theatres where low light levels often occur, and in such circumstances it is simply not possible for the person who is trying to move around to switch on the lights. Some cinemas and theatres try to alleviate such problems by providing torch-bearing ushers to guide patrons to their seats, but the ushers tend to leave once a film or play has commenced and hence cannot help patrons who need to move around once the film or play has started.
Electricity wastage can also occur in commercial environments, such as offices, where corridors or staircases are often permanently lit even when they are not being used. Although it is know to link lighting systems to PlR sensors, such an arrangement still uses a relatively large amount of electricity because the lights to which the PIR sensors are coupled are not typically particularly environmentally friendly.
It is the case, therefore, that there is a need in the art for an illumination device which addresses these problems. It is also the case that there is always a desire in the art for new designs of illumination devices that may be used either as decorative pieces of art, or functional articles.
Summary of the Invention
It is an aim of the present invention to address one or more of these problems, and to this end a presently preferred embodiment of the present invention provides an illumination device configured for use as a floor or wall covering, the device comprising: a generally planar outer surface that comprises a plurality of regions arranged in a predetermined pattern through which light can be emitted; an electroluminescent light source comprising a plurality of electroluminescent light source elements that each include a pair of electrical contacts for the supply of electrical power to the corresponding light source element, the light source elements being arranged so that at least one element is provided in each of said regions; a power supply unit (e.g. a unit such as a battery, or an interface to an external power source); and a control module that is configured to couple the electroluminescent light source to the power supply unit for the supply of power to said light source in response to a detected stimulus, the control module including a pattern generator that is operable to energise one or more of the light source elements of said electroluminescent light source to provide one or more predetermined illuminated patterns; wherein the planar outer surface and electroluminescent light source are configured and arranged so that the generally planar outer surface forms a carrier for said light source and so that light can be emitted through said regions.
Another embodiment of the present invention provides an illumination device that is suitable for use as a floor or wall covering, the device comprising a generally planar surface; an electroluminescent light source arranged in a predetermined pattern; and a switch that is configured to couple the electroluminescent light source to a power supply when switched from one state to another; wherein the planar surface and electroluminescent light source are configured and arranged so that the generally planar surface forms a carrier for said light source that enables said pattern to be viewed, at least whilst said light source is energised and emits light.
Yet another embodiment of the present invention relates to an illumination device that is suitable for use as a floor or wall covering, the device comprising a generally planar surface; an electroluminescent light source arranged in a predetermined pattern; and a controller that is configured to couple the electroluminescent light source to a power supply in response to a detected stimulus; wherein the planar surface and electroluminescent light source are configured and arranged so that the generally planar surface forms a carrier for said light source that enables said pattern to be viewed, at least whilst said light source is energised and emits light.
The light source may comprise electroluminescent wire or an electroluminescent sheet.
The electroluminescent sheet may be formed by printing (e.g. by screen or ink jet printing) layers of material onto a substrate. The device may comprise a sensor coupled to said controller for sensing said stimulus. The stimulus may comprise one or more of: light, sound, temperature or pressure.
In a particularly preferred arrangement the device may be configured for use as a stair carpet, the arrangement being such that the electroluminescent light source is configured to illuminate each of the steps of the stairs when said stimulus is sensed.
The device may comprise a sensor for placement adjacent a top step of the stairs and a sensor for placement adjacent a bottom step of the stairs, the controller being configured to illuminate the light source when a said stimulus is detected at one of said sensors, and to continue to illuminate said light source at least until a said stimulus is detected at the other of said sensors.
Another embodiment of the invention may comprise an illumination device configured as a rug or wall-hanging, the device comprising a substrate having an electroluminescent light source printed on one side thereof and a pressure sensor formed on the other side thereof, a control module configured to interface with said electroluminescent light source and said pressure sensor, a backing layer to which said substrate is configured to be adhered, and a cover layer that is configured to be adhered to said backing layer and over said substrate so as to sandwich said substrate between the cover layer and said backing layer, the cover layer including one or more means for permitting light from said illumination device to emanate from the light source through said cover when the light source is energised. The illumination device and said pressure sensor include electrodes that are configured to converge at a tongue portion of said substrate, said tongue being pluggable into a slot connector provided in said control module.
The tongue portion may be locally stiffened.
Further preferred features of these and other embodiments are set out in the accompanying claims, and other aspects, features and embodiments of the invention, and advantages thereof, are set out elsewhere in the application.
Brief Description of the Drawings
Various aspects of the teachings of the present invention, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which:
Fig. 1 is a schematic plan view of a rug embodying the teachings of the present invention;
Fig. 2 is a part section through the rug along the line A— A shown in Fig. 1 ; Fig. 3 is a schematic of the rug components illustrating the manner in which they are connected to one another;
Fig. 4 is an exploded view of the assembled rug; and Fig. 5 is a photograph of the rug in operation;
Fig. 6 is a cross section through an illustrative electroluminescent light source for a second embodiment of the present invention;
Fig. 7 is a schematic view of an illumination device for this second embodiment; Fig. 8 is a schematic view of another component of this second embodiment, which component is complementary to that depicted in Fig. 7;
Fig. 9 is a perspective view of a power and control module for this second embodiment;
Fig. 10 is a schematic view of the underside of the component depicted in Fig. 9; Fig. 11 is a schematic illustration of the manner in which the components of the second embodiment may be assembled together to form a rug; and
Fig. 12 is a schematic representation of an illustrative control module for use with the teachings of the present invention.. Detailed Description of Preferred Embodiments
Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, and with particular emphasis on the application of the teachings of the present invention to a floor covering such as a rug. The teachings of the invention are, however, more widely applicable, and as such the following description should not be construed as a limitation of the teachings of the invention to floor coverings.
With this in mind, Fig. 1 shows a shag pile rug 1 in which a control circuit 7 is embedded. The rug 1 includes an electroluminescent wire (EL wire) 4 that has been encapsulated within a transparent protective layer 3, and arranged to form a pattern on the rug 1.
Referring now to Fig. 2, the rug comprises a backing 2 (preferably a non-slip backing, for example of rubber) to which an optional shock absorbing layer 5, for example of a polypropylene foam of the type supplied by Zotefoam®, has been added. The rug shag pile 1 is fixed to the layer 5, and the shag pile includes a pattern that consists (at least party) of a continuous groove in which the EL wire 4 is provided.
As depicted in Fig. 3, the controller 7 is coupled to a power source 9 and to a sensor 11. In one embodiment the power source comprises a transformer that is configured to be coupled to a mains power supply. In another preferred embodiment the power source comprises a battery that is coupled to the controller by way of an inverter so as to supply the controller with an AC voltage for powering the EL wire.
If the power source comprises a battery, then means may be provided for recharging that battery in situ in the rug. For example, the rug may include a small flexible solar panel that is configured to charge the battery during the hours of daylight. Alternatively, the battery may be removable from the rug for recharging at a separate recharging point. In a particularly preferred arrangement, the batteries may comprise generally flat rechargeable polymer batteries that are sufficiently flexible to enable the rug to be rolled up for storage and transport.
The controller 7 is, in this illustrative example, connected to one continuous length of EL wire 4 arranged in the aforementioned pattern. In other arrangements the controller may be connected to multiple lengths of EL wire that each define a region of the pattern on the rug, and in such arrangements the controller 7 may be arranged to simultaneously energise all lengths of EL wire, to energise one length after the other or to energise the lengths of wire in any other sequence. The controller 7 includes timer functionality 13 to control when the EL wire is de- energised, and (in this embodiment) fader functionality 15 to control the manner in which the EL wire is energised and de-energised (specifically to fade-on and/or fade-off the EL wire by ramping up and ramping down the power supplied thereto). The timer functionality specifies how long the EL wire remains lit before being de-energised, and in a preferred embodiment this time period may be adjustable. In another arrangement it is possible to disable the timer so that the wire remains energised until switched off.
In general, the sensor may comprise any device that generates an output in response to a stimulus. For example, the sensor could comprise a photodetector that is configured to generate an output when the ambient light level crosses a given threshold (for example to generate a signal when the ambient light level drops below a given threshold). In another arrangement the sensor could comprise an audio detector that is configured to generate a signal when sound is detected. In a particularly preferred arrangement the sensor may comprise one or more pressure sensors, for example one or more capacitative pressure sensors. Such capacitative sensors comprise a pair of conducting plates that are separated by a dielectric, the arrangement being such that the capacitance of the plate/dielectric assembly changes as one plate is moved towards the other by the application of pressure thereto. This change in capacitance is detectable, for example by the controller.
Fig. 4 is a schematic representation of a particularly preferred arrangement. As shown, the rug 17 comprises a non-slip backing 19 (e.g. of rubber) to which a carpet layer 21 is stitched, the carpet layer including a pattern 23 configured as a groove into which an electroluminescent wire 25 can be inserted.
Between the carpet layer 21 and backing 19 there are provided a plurality of pressure sensors 27 that are connected to a controller 29 that is, in turn, connected to a battery 31 and the aforementioned electroluminescent wire 25. The controller 29 is also connected to a mode switching module 33 that comprises a number of switches that can be operated by a user to cause the controller to operate the wire in any of a number of different modes. For example, operating one switch may configure the controller to fade up the wire when pressure is detected at the pressure sensor, another may configure the controller to flash the wire when pressure is detected at the pressure sensor, and so on. In a particularly preferred arrangement the location of the switch module is signified by a logo for each switch, the logo being fashioned from EL wire that is configured to illuminate with the remainder of the EL wire in the rug.
In a particularly preferred arrangement, the backing 19 and carpet layer 21 are fixedly attached to one another around the periphery of the rug except for one small section generally adjacent the battery. In this section of the periphery of the rug it is preferred for the backing to be joined to the carpet layer by means of complementary components 35a, 35b of a two-part mechanical hook-and-loop fastener (such as Velcro®). By virtue of this arrangement it is then possible to separate the complementary components 35a and 35b to provide access to the battery for charging or replacement, as necessary. Fig. 5 is a photograph of a rug according to this embodiment of the invention in use. As shown, the pattern in the rug defined by the EL wire is clearly visible, and in a preferred arrangement the EL wire is chosen to provide an illumination of at least 50 lumens, such a level of illumination being sufficient to enable a person to see where they are going in an environment with low ambient light levels. This embodiment of the invention is implemented by means of an electroluminescent wire. In another embodiment, to be described hereafter, the wire may be replaced by an electroluminescent sheet, and in one particularly preferred arrangement this sheet may be formed by screen printing on a suitable substrate. '
Referring now to Fig. 6 of the accompanying drawings, there is depicted a schematic representation of an electroluminescent sheet. As shown, such a sheet comprises a transparent electrically conducting film (the transparent electrode film) that forms a first electrode of the sheet (Orgacon® is a particularly preferred material for this first electrode). The transparent film overlies a luminescent layer that is supplied with power by a bus bar, and is spaced from a rear electrode by an insulating layer. The rear electrode is connected to a second bus bar, and when an appropriate AC voltage for the particular luminescent layer employed (e.g. an AC voltage of c. 200 to 450 Hz) is applied to the bus bars, the luminescent layer provides light that escapes from the electroluminescent sheet via the aforementioned transparent film.
Electroluminescent sheeting can be purchased "off the shelf and cut into any desired pattern (so long as appropriate electrical connections are maintained), and as such the electroluminescent wire of the first embodiment could readily be replaced with "off the shelf electroluminescent sheeting that has been cut to the required shape and affixed, for example adhered, to the backing with a carpet layer provided thereover, the electroluminescent sheeting being exposed through appropriately shaped holes in the carpet layer.
Whilst such an arrangement would function adequately, it would necessarily increase the cost of the rug as there would invariably be considerable wastage of one of the most expensive components of the rug, namely the electroluminescent sheet.
In an alternative arrangement that is particularly preferred, the electroluminescent sheet may be constructed, to the required pattern, by depositing layers of material onto a suitable substrate. This deposition could be accomplished by means of a technique such as ink jet printing, but in a preferred arrangement the layers are screen printed onto the substrate.
Fig. 7 is a schematic representation of a flexible substrate 37, for example of polyester, onto which appropriate bus bars 39 have been printed, the bus bars being arranged to supply power to top and bottom electrodes of (in this instance) two pattern areas 41 that are to be illuminated. Each of the pattern areas is constructed as depicted in Fig. 6 to have a rear electrode (i.e. nearest to the substrate) contacted by a first bus bar, an insulating layer provided over the rear electrode, a luminescent layer, and a transparent front electrode film (for example of Orgacon®) that is contacted by a second bus bar. The two bus bars converge, as shown, at a tongue 43 which may be stiffened (as compared to the remainder of the substrate) so as to be relatively rigid.
In a particularly preferred arrangement a pressure sensor is formed immediately underneath the substrate 37 depicted in Fig. 7. To achieve this, a first conducting layer may be printed onto the underside of the substrate, following which a dielectric layer is provided thereover and a second conducting layer is provided on top of the dielectric. The three layers may be sealed around their periphery to the substrate to thereby provide a capacitative pressure sensor that is significantly less bulky than pressure sensors of the type used in intruder alarm systems. In one envisaged implementation the three layers may be printed onto the underside of the substrate 37. A pair of electrical contacts (not visible) are printed onto the underside of the substrate 37 (a first of these contacts being connected to the first conducting layer and a second being connected to the second conducting layer) and these contacts are extended to the end of the underside of the tongue 43.
Referring now to Fig 8 of the drawings, the substrate 37 is overlaid (as will later being explained with reference to Fig. 11) by an outer layer 45 that may be of shag pile, or (in a particularly preferred arrangement) may be of felt. The outer layer 45 has (in this instance) a pair of apertures 47a, 47b which are configured to overlie the pattern areas 41 on the substrate 37, although it will be appreciated that the pattern layers 41 need not be the same shape as the apertures (as shown) but may instead simply be easily printed regular shapes (such as circles, squares or rectangles) that are larger than the apertures.
Referring now to Fig. 9, there is shown a power supply and control module 49 according to a particularly preferred embodiment of the present invention.
The module comprises a slim line unit (for example less than 6mm in height) which accommodates the control circuitry necessary to implement the invention, and which provides a housing for a slim line battery. In the preferred arrangement the module includes integrated circuit inverter (to effect conversion of the DC battery output to AC) and other control components surface mounted on a PCB. As the module is relatively small it can readily be integrated into the rug, for example by being tucked into one of the corners, and the exterior housing of the module is chosen to be sufficiently robust (for example of plastics - e.g. injection moulded polypropylene) to protect it underfoot.
The module 49 includes a slot 51 into which the tongue 43 of the substrate 37 can inserted so as to interface the power and control circuitry within the module with the pressure sensor on one side of the substrate and the electroluminescent areas 41 on the other. Providing a slot interface of this type greatly facilitates assembly of the rug components during the manufacturing process.
Fig. 10 depicts the other side of the module 49 to that shown in Fig. 9 (as well the manner in which the tongue interfaces with the slot 43, and the pressure sensor contacts on the underside of the substrate 37). As shown this side of the module 49 includes a door 53 that can be opened to give access to a battery unit (not visible) that powers the rug. The battery unit is preferably rechargeable, and may comprise any type of battery including rechargeable Thin Film Batteries (TFB's) and organic radical batteries. In use, a charged battery unit can be inserted into the module via the door 53, and once the battery unit has discharged the door 53 can be opened and the battery can be removed from the module for recharging in a separate charging dock. In another arrangement, a socket may be provided to enable the battery unit to be plugged into a wall unit whilst in situ in the module 53 for recharging.
Referring now to Fig. 11 of the drawings, there is shown a schematic representation of the manner in which the various components of this embodiment may be assembled to form the rug.
In a first step, the power and control module 49 is connected to the substrate tongue 43, and the module / substrate assembly is fixed (for exampled adhered, e.g. by way of a silicone based adhesive) to a backing layer 55 (for example a non-slip layer, e.g. of rubber) in such a way that aforementioned door 53 on the underside of the module 49 is accessible via a gap 57 in the backing 55 (which gap may be plugged by an insert 59 that can be temporarily fixed in the gap 57). The outer layer 45 is then fixed (for example adhered, e.g. by a silicone adhesive) to the substrate and backing, following which a decorative binding may be applied to the edge of the mat.
Referring now to Fig. 12 of the accompanying drawings, there is shown a particularly preferred control module for use with the embodiments of the present invention, particularly but not exclusively with the second embodiment aforementioned. The control module 61 comprises, in the preferred arrangement, a rechargeable battery 63 that is coupled to a voltage regulator 65 that ensures a constant output voltage is provided from the battery, at least until the battery has run out of charge. The voltage regulator 65 is coupled to an inverter 66 to change the DC battery output to and AC signal for driving a plurality of electroluminescent lighting elements 67. The inverter is coupled to the EL elements 67 by way of a pattern generator 69 that is coupled to one or more switches 71 and to a pattern selector 73.
The control module may be powered directly from the DC output of a transformer 75 that is coupled to the mains and to the control module at point B. In a more preferred arrangement the battery 63 may be coupled for recharging to a photovoltaic panel or mains DC power source 77 by means of a charger 79.
The pattern generator may be configured to illuminate one or more of the EL elements in a predetermined pattern, and in a particularly preferred arrangement may be configured to illuminate the EL elements in a plurality of different combinations - each of which provides a different illumination pattern. In a particularly preferred embodiment the pattern generator is coupled to a pattern selector that enables the user to select the pattern in which the generator will illuminate the EL elements. The pattern selector may comprise a simple toggle switch. In another envisaged mode of operation, the pattern generator may be configured to illuminate EL elements in a random pattern. In another embodiment the pattern generator may alternatively or additionally be configured to illuminate the EL elements in one or more sequences, and these sequences may be user selectable by means of the aforementioned pattern selector (or by any other means).
In use, when the pattern generator detects that one or more of the switches 71 has changed state, it couples one or more of the EL elements to the power source (e.g. the battery) to illuminate the EL elements in a predetermined pattern. The pattern generator may comprise timing circuitry that turns off the EL element(s) one a predetermined period of time has elapsed.
By way of illustrative, non-limiting example, the pattern generator could comprise a state machine - namely an array of components configured and optionally switch selectable to provide one or a set range of predetermined sequences. Illustrative examples of state machines include FPGA (field programmable gate array), PAL (programmable array logic), GAL (generic array logic), CPLD (complex programmable logic device) - some of which may include a microcontroller and thus be programmable. Other options include a PIC (e.g. an 8/16/32 bit PIC or an rfPIC), a STAMP or a so- called system on chip solution. In an envisaged implementation the pattern generator may be programmed by means of code written in PIC ASM, PALASM or C++, C# or other dedicated high or low level languages and the code then ported across into an onboard ROM as a OTP (one time programmable) or reprogrammable RAM/Flash Memory etc. The pattern generatos may be a single circuit for all EL elements or a plurality of individual circuits - one per EL element. In one envisaged implementation the EL elements could each be driven by a typical mobile phone type driver chip such as the Rogers Corporation Durel Division D355B (up to 5 square inches)
In another envisaged mode of implementation, the pattern generator may comprise a sequencer circuit that employs a basic STAMP BS2 controller which provides isolation and is driven by a single driver/inverter.
It will be apparent from the foregoing that we have described herein an illumination device that addresses at least some of the problems posed by the prior art. As mentioned above, the teachings of the present invention are more widely applicable than rugs. For example, the teachings of the present invention could readily be employed in a stair carpet (for example in a nursing home) where the pressure sensors are located adjacent the top and bottom steps of the stair, and when stepped on cause the edges of each of the steps of the stairs to be illuminated. In one particularly preferred arrangement the stair carpet light could be arranged so that once switched on by pressure at the top of a flight of stairs it will remain on until pressure is detected at the bottom of the stairs, following which it will automatically switch off. Such an arrangement could also be employed in cinemas to assist patrons moving around in the cinema once the main auditorium lights have been switched off.
It will be appreciated that whilst various aspects and embodiments of the present invention have heretofore been described, the scope of the present invention is not limited to the particular arrangements set out herein and instead extends to encompass all arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims.
For example, in one envisaged modification, the material of the rug could be adapted to include a luminous material so that energising the electroluminescent light functions to charge the luminous material. This could be accompanied by impregnating at least part of the rug with a luminous dye. Other optional features are: other light sources may instead or additionally be provided, for example the device could include LED's or photoluminescent light sources; the photovoltaic panels aforementioned need not be flexible; the pressure sensor may comprise a touch sensitive film or membrane switch; the device could be configured as a modular unit for use as floor tiles with each unit sub-populated with different power units; the pattern generator may be programmed by wireless means (for example via a mobile phone); if the modular flooring was in a matrix array then text messages could be sent to it in a 'pre-determined' seven segment text array; piezoelectrics could be employed as detection or trigger device; and the light source elements need not be white light or all of the same colour (any colour or combination of colours can instead be employed).
It should also be noted that whilst the accompanying claims set out particular combinations of features described herein, the scope of the present invention is not limited to the particular combinations hereafter claimed, but instead extends to encompass any combination of features herein disclosed.