WO2007020455A1

WO2007020455A1 - Illumination apparatus

Info

Publication number: WO2007020455A1
Application number: PCT/GB2006/003091
Authority: WO
Inventors: Andrew Mcpherson
Original assignee: Andrew Mcpherson
Priority date: 2005-08-17
Filing date: 2006-08-17
Publication date: 2007-02-22
Also published as: GB0516901D0

Abstract

An illumination apparatus suitable for creating a continuously variable random pattern suitable for use with a heating appliance in order to generate a flame image. The apparatus comprises housing (10) having a light source (20) arranged to directly project light onto an unslitted reflective sheet (45) . The housing further includes a front panel (11) , which forms a viewable screen, such that the reflective sheet (45) is viewable therethrough and the area of the sheet is greater than the area of the front panel.

Description

ILLUMINATION APPARATUS

The present invention relates to an illumination apparatus suitable for creating a continuously variable random pattern useful for simulating an image, such as a flame.

Although the illumination apparatus is of general application, it will find most suitable use with a heating appliance in order to generate a flame image. Various techniques for simulating flame images exist. These are used with heating appliances such as an electric element or gas burner so as to mimic the appearance of a real fire. One such technique is described in UK Patent Publication No GB2391614A, which relates to a flame simulating apparatus comprising a light source, a lens formed from a plurality of laminated sheets of translucent material, through which light from the light source is projected. The light from the light source is projected onto a back screen, which is fixed on a rear part of the apparatus, and onto a plurality of strips of thin flexible reflective material which are mounted vertically on the rear part, in front of the back screen, and tethered at either end. The application of an air stream to the strips makes them to flutter causing the light incident thereon to appear to move somewhat like a flame.

An object of the present invention is to provide an improved technique for simulating an image such as a flame picture suitable for use with a heating appliance such as an electric fire.

Accordingly, the present invention provides an illumination apparatus suitable for simulating flames, the apparatus comprising a housing having a light source arranged to directly project light onto a continuous reflective sheet. The housing further comprises a front panel which forms a viewable screen such that the reflective sheet is viewable therethrough and the overall dimensional size of the sheet in respect to the front panel is greater and thus the fluttering effect of the sheet when an air flow is provided is improved.

The sheet is movable within the housing in response to the circulation of air in the housing preferably by a fan.

Furthermore, it is preferable for the sheet to be of sufficient weight in order to cause it to drape when fixed in the housing. In order that the present invention be more readily understood, embodiments thereof will be described by way of example only, with reference to the accompanying drawings in which:

Fig 1 is a perspective view of an illumination apparatus according to a preferred embodiment of the present invention with the front panel partially cut away so as to show the internal features of the apparatus;

Fig 2 is a side view of the apparatus shown in Fig 1 ;

Fig 2A shows a simplified side view of an alternative arrangement of the PCB in the apparatus; Fig 3 shows a perspective view of a printed circuit board used in Fig 1 and 2;

Fig 4 shows a simplified view of the apparatus in Fig 1 detailing one way of attaching the reflective sheet in the chamber; and

Fig 5 and 5a shows another way of attaching the reflective sheet in the chamber compared to Fig 4. Fig 1 and 2 shows a preferred embodiment of the apparatus according to the present invention. A housing 10 comprises a front panel 11, a back panel 12 and a pair of side walls 13 separating the front panel 11 and back panel 12.

The inside of the housing 10 is viewed through the front panel 11 which is glazed and preferably partially obscured. This is achieved by laminating an etched glass diffusion screen (not shown) with a graded screen (not shown) comprising a plurality of circular apertures of different sizes. In this embodiment, the relative size of the apertures decreases on moving up the screen. In this way, the contents which are placed behind the screen are more prominently visible at the bottom of the screen than at the top. Alternatively, the front panel 11 may be glazed and tinted. This is achieved by using an etched glass diffusion screen (not shown) and applying a tint coating thereto. The tint may be applied such that the transparency through the bottom of the screen is greater than the top.

The back panel 12 is formed of a rigid material. The side panels 13 which separate the front panel 11 and back panel 12 are also formed of a rigid material similar to the back panel. The front panel 11 extends down to a lower section of the housing 10 such that the front of the lower section can accept ambient air into the lower section. However, the back panel 12 extends to the bottom of the housing 10 such that air cannot enter through the back of the housing 10. The lower section of the housing 10 comprises a digital light module 20 for providing light into the apparatus and a fan 30 for providing a flow of air into the apparatus.

With reference to Fig 3, the module 20 is formed from a printed circuit board (PCB) 21 and is constructed such that a plurality of slots 22 are located on the PCB 21 so as to enable air to pass from the top to the bottom and vice versa.

The slots 22 separate sections 23 of the PCB 21 on which light emitting diodes (LEDs) 24 are mounted. Each section 23 is provided with a plurality of LEDs which in this case in the form of a linear array which are controlled by a programmable controller which is preferably a processor chip (not shown). The LEDs 24 are electrically connected to the controller by the conductive tracks on the PCB 21. Each array comprises 5 or 6 LEDs but this number may be varied and different number combinations in each array may be used.. The chip can be adapted so as to cause the LEDs to give different types of lighting effects. For example, any of the following may be provided: random flicker; variable rise and fall in light intensity; random mix of which LEDs are active at any moment; colour mix selection; bar light projection; and transverse wave light projection.

With particular reference to the colour mix selection, this would be possible by providing different colour LEDs 24 on the PCB 21 and mixing the combination of the activation of the LEDs in order to produce a particular colour or effect. For example, blue and red LEDs would project lilac. The colour of the LEDs 24 may vary within each linear array or different colour combinations of arrays may be used.

It will be appreciated that various types of LED 24 may be utilised in order to provide any desired effect. Alternatively, the light module 20 could be replaced by one or more incandescent or fluorescent light bulbs as a source of light. Underneath the light module 20 is located the fan 30 which is preferably a tangential fan. The fans are powered by either an AC or DC motor (not shown). An AC motor would typically be powered from mains voltage, and a DC motor typically from a rectified voltage provided by a separate AC to DC power supply (i.e. 240V AC rectified to 24V DC).

As shown in detail in Fig 2, the fan 30 is located in the lower section of the housing 10 such that ambient air can enter from the outside of the apparatus, through the front of the lower section and is sucked towards the fan 30. The air then passes through the slots 22 of the PCB 21 and into a chamber 40 above the lower section of the housing 10.

The rotation of the tangential fan 30 causes a turbulence which allows air to both enter and exit the chamber 40 through the slots 22 in the PCB 21. In particular, the fan 30 is arranged to rotate clockwise and drives air upwards as shown by arrow A through the rear slots 22a of the PCB 21 and recycled air is drawn out of the chamber

40 through the front slots 22b of the PCB 21. The top of the chamber 40 is provided with an opening to enable air at the top of the chamber to be released from the housing

10. The separation of the rear slots 22a and front slot 22b provides the improved turbulent effect. However, the PCB may be adapted so that the slots are not separated such that air enters and exits the chamber through the same slot. Furthermore, the number of slots can be changed by adapting the design of the PCB accordingly.

In an alternative embodiment (not shown) the PCB is replaced by a single slotted platform on which LEDs are mounted. With this configuration, the LEDs would be connected to the controller by wires. However the same effect of allowing air to pass between the lower section of the housing and the chamber would be achieved.

Although Fig. 1 and 2 show the PCB 21 substantially horizontal, in another embodiment the PCB 21 may be positioned at an angle with respect to the base of the apparatus. This is shown in Fig. 2A.

In this arrangement, a platform 25 is provided with is horizontal and comprises one or more slots to enable air flow from the fan 30 therethrough. A PCB 21a is positioned at an angle such that one end abuts the platform 25 and the other end abuts the front panel 11. The PCB 21a differs to PCB 21 of Fig. 1, 2 and 3 in that a plurality of slots are not required. This enables the PCB 21a to be manufactured more easily than PCB 21. It will be appreciated that the turbulence within the chamber 40 can be controlled by the fan 30 so as to direct air upwards, forwards, or backwards in the chamber 40. Furthermore, it will be apparent that other means of controlling the turbulence within the chamber 40 may be utilised and the apparatus is not restricted to tangential fans.

As shown in Fig 2, the chamber 40 is located above the lower section of the housing 10 and is structurally defined by the front panel 11, side walls 13, a substantial portion of the back panel 12 and the base of the chamber 40 is provided by the light module 20. Within the chamber 40 is provided a reflective material 45 arranged to reflect incident light rays from the light module 20 towards the front panel 11. The material 45 is preferably a single reflective unslitted sheet which is partially pleated and then fixed at the top of the chamber 40. In particular, the material 45 may be a polyester jersey base fabric which is woven and sufficiently weighty enabling it to drape from the top of the chamber 40 and billow when an air stream is supplied. The base is covered with tiny dots of reflective material such as paint. Preferably, the material 45 is that sold under the trade name Liquid Lame but it will be appreciated that other materials with similar mechanical and optical properties may be utilised.

It will be appreciated that an unslitted woven sheet is continuous in that gaps which enable two parts of the sheet to move independently of each other are not present. However, the use of continuous is intended to cover pin holes in the sheet as this would not effect the overall performance of the sheet. Indeed, the woven material is by its very nature composed such that, depending upon the density of the weave, air can pass through the weaves. The continuous sheet is formed such that a ripple is created in the sheet surface due to the air flow from the fan and the ripple is allowed to progress in a waveform both vertically and horizontally across the sheet surface. The use of a continuous sheet with these properties improves the flame picture compared to slitted sheets or sheets with cuts which combined with air flow cause independent movement of portions of the sheet thus effecting the overall flame picture. A slit in the sheet would terminate the waveform progression and expose an un-natural edge thus disrupting the billowing effect which is to be provided by the continuous sheet. The size of the sheet 45 is such that the area of the sheet is greater than the area of the front panel 11. The area is dependent on the length and the width of the sheet. As the length is greater, the sheet 45 can billow if a turbulent air stream is provided and the width of the sheet enables the pleated configuration to be provided. Accordingly, the overall dimensional size of the sheet in respect to the front panel is greater and thus the fluttering effect of the sheet when airflow is provided is improved. Moveover, the larger relative size provides depth and three dimensional properties to the created image.

The sheet 45 may be fixed at the top of the chamber 40 in any appropriate manner such as adhesive or, as shown in Fig 4, to a plurality of hooks 46a arranged on the back panel 12. If the latter is the case, the sheet 45 is provided with corresponding holes (not shown) to receive the hooks 46. With this arrangement, the sheet 45 would be fixed at the top and bottom to the back panel 12 in a pleated configuration.

Alternatively, as shown in Fig 5 and in more detail in Fig 5 a, the sheet 45 may be fixed by being suspended from a small diameter rod 46b which is arranged along the top of the chamber 40 and each respective end is fixed to a side wall 13. A plurality of holes 47 in the sheet 45 are arranged to receive the rod 46b therethrough and the pleated arrangement is preferably achieved by passing the rod 46b respectively through the front and back of adjacent holes 47. With this arrangement the top of the sheet 45 would be fixed to a rod 46b in a pleated manner and the bottom of the sheet 45 would be fixed to the back panel 12. This creates a tapered arrangement such that the top of the sheet 45 may be closer to the front panel 11 than the bottom of the sheet 45. The amount of tapering can be varied by moving the rod 46b with respect to the front panel 11. That is, the closer the rod is positioned to the front panel, the more tapering which is present.

In an alternative embodiment (not shown) to that shown in Fig. 4 and 5, the top of the sheet 45 extends over and behind the back panel 12 and is fixed by means of adhesive to the back surface of the back panel 12. This arrangement as with the embodiments in Fig. 4 and 5 also allows freedom movement and access at the top behind the sheet to prevent rear suction which would be detrimental to the flame image. As mentioned above the overall size of the sheet 45 is greater than the size of the front panel 11. Furthermore the overall size can be compared to another point of reference. That is, the length of the sheet 45 is greater than the distance between the top of the chamber 40 to which the sheet 45 is mounted and the bottom of the chamber 40 where the sheet 45 is also mounted. The width of the sheet 45 is greater then the distance between the side portions of the chamber 40 to which the sheet 45 are mounted.

The use of the apparatus is such that when the fan 30 is switched on and the light module 20 is powered, vertical light emissions from the LEDs 24 create a rising flame impression on the reflective sheet 45. The sheet 45 billows in the turbulence created by the flow of air between the lower section of the housing 11 and the chamber 40.

In a modification, some of the surface of the sheet 45 may be provided with a non reflective coating in order to prevent the reflection of stray ambient light which may exist in the environment in which the illumination apparatus is to be utilised. In particular the higher extremities of the sheet may be provided with a matt surface such as paint to reduce the reflections due to ambient light outside the flame picture focus areas.

In an alternative configuration to that shown in Fig. 1, 2 and 2A, the fan is arranged to draw air into the housing through the back of the lower section instead of the front such that the rotation of the fan is reversed (i.e. anticlockwise) and the back of the housing has an opening to allow air to enter.

It will be appreciated that the random light which is capable of being emitted from the multiplicity of individual LEDs 24 incident onto a rising free moving reflective sheet 45 allows a viewer to see a simulated flame image through the front panel of the apparatus. The apparatus provides a truly rising, deep flame image in convincing colour, with effective flicker and variable light density.

Although the preferred embodiment relates to the generation of a flame image for use with heating appliances, it will be apparent that the present invention can be adapted for use in other applications. For example, by changing the colours of the

LEDs, different LED impressions can be gained such that if blue and green LEDs are used, the apparatus may be used to simulate cooling effects. Furthermore, the apparatus may be used for purely decorative purposes.

Claims

CLAIMS:

1. An illumination apparatus for simulating a continuously variable random pattern, the apparatus comprising a housing comprising a light source and a single unslitted reflective sheet, wherein the light source is arranged to directly project light onto the reflective sheet, the housing further comprising a front panel for viewing the reflective sheet therethrough wherein the area of the reflective sheet is greater than the area of the front panel.

2. The apparatus according to claim 1 wherein the reflective sheet is a single sheet of continuous woven material.

3. The apparatus according to claim 1 or 2 wherein the width of the sheet is greater than the width of the front panel and the length of the sheet is greater than the height of the front panel.

4. The apparatus according to claim 1, 2 or 3 wherein the sheet is arranged in the housing in a pleated configuration.

5. The apparatus according to any preceding claim further comprising a means for circulating air in the housing wherein the reflective sheet is movable within the housing in response to air being circulated by the circulating means

6. The apparatus according to any preceding claim wherein the sheet is suspended from a rod arranged horizontally across the top of the housing.

7. The apparatus according to any preceding claim wherein the front panel is glazed and tinted.

8. The apparatus according to any of claims 1 to 6 wherein the a front panel which is glazed and partially obscured.

9. The apparatus according to claim 8 wherein the front panel comprises a plurality of apertures, wherein the relative size of the apertures decreases on moving down the panel.

10. The apparatus according to any preceding claim wherein the light source comprises an incandescent light bulb.

11. The apparatus according to claim 10 wherein the light source comprises a plurality of incandescent light bulbs .

12. The apparatus according to any of claims 1 to 9 wherein the light source comprises a plurality of light emitting diodes (LED) which are controlled by a programmable controller.

13. The apparatus according to claim 12 wherein the LEDs are mounted on printed circuit board (PCB) and the PCB comprises a slot.

14. The apparatus according to claim 13 wherein the PCB comprises at least two slots, wherein a first slot is spaced with respect to a second slot such that the circulating means is arranged to cause air flow in one direction through the first slot and in the opposite direction through the second slot.

15. A heating appliance incorporating an illumination apparatus as claimed in any of the preceding claims.