GB2264555A

GB2264555A - Flame effect display

Info

Publication number: GB2264555A
Application number: GB9303409A
Authority: GB
Inventors: Philip Coats
Original assignee: KENHOLME APPLIANCES
Current assignee: KENHOLME APPLIANCES
Priority date: 1992-02-28
Filing date: 1993-02-19
Publication date: 1993-09-01
Anticipated expiration: 2013-02-19
Also published as: GB9303409D0; GB2264555B; GB9204362D0

Abstract

A flame effect display 22' has a plurality of electrically powered light sources, such as LEDs, 26' arranged in the form of one or more flames. The light sources can be controlled to go on and off in groups in such a sequence as to reproduce the appearance of flickering flame(s). The display is located above a fuel effect display 30' to simulate flames rising from fuel. The display 30' has bulbs or LEDs 31 which are turned on/off such as to give the effect of fuel glowing more or less brightly. The displays 22', 30' may be controlled in unison. The light sources 26' may be of different colours, and may be controlled so that the size of the flame(s) appears to increase and decrease. A diffuser screen 27' is provided. In another embodiment (Fig 1, not shown), a glass sheet (19) above a fuel effect display (30) reflects an image of the flame effect. The display may be part of an electric fire. <IMAGE>

Description

FUEL AND/OR FLAME EFFECT This invention relates to electrical devices which simulate a flame or glowing fuel, for example electrical flame-effect fires.

It is known to simulate a flickering flame in an electrical fire by rotating a reflector in front of light bulbs. The reflector interferes with the direct passage of light to a coal-effect, or log-effect, moulding and simulates flickering, both on the moulding and on a back panel. It is also known from GB 2 232 481 to modulate light from a light source using a different intervening mechanism, namely a randomly or pseudorandomly switched LCD array interposed between a light bulb and a log or coal-effect moulding. Furthermore, we are aware of the proposal set forth in US 4 253 045 in which light bulbs in an array of electric light bulbs are pseudorandomly switched on and off by a controller so as to generate a controlled variable light so as to simulate a flickering light.

The aim of one aspect of the present invention is to provide another flame effect display. The aim of another aspect of the invention is to provide a fuel effect display.

According to a first aspect of the invention we provide a flame effect display comprising a plurality of electrically powered light sources, the current to the light sources being controlled so as to cause the light sources to come on and go off in such a sequence as to reproduce a flickering flame.

Thus we directly reproduce the shape and effect of a flame by controlling the light sources in a predetermined manner, rather than having simply a randomly flickering light.

The light sources may be set out in a grid or regular pattern, but we prefer to arrange them in the shape of one or more flames. This can enable us to use fewer light sources.

Our "flame" may appear to increase and decrease in size as well as an overall region of the flame increasing and decreasing in intensity. The flame may also be controlled so as to move sideways, for example as if caught by a draught.

The light sources are preferably LED's We have found that LED's are suitable for simulating a flickering flame, despite a prejudice against them because they generate so little light.

Preferably the display has a diffuser screen provided in front of the light sources.

The light sources may comprise one or more light sources of a first colour and one or more of a second colour. Light sources of a third colour, or further colours, may also be provided.

Preferably a particular flame of the display includes light sources of more than one colour. When we arrange our light sources to be in flame shapes a particular flame shape preferably includes light sources of more than one colour.

The light sources are preferably controlled in a plurality of groups, the light sources of a particular group being controlled simultaneously in the same manner. Light sources in a particular group may be present in different flames of the display, and/or may have different colours. Light sources at the base of the flames may be of a different colour from those at the top of the flame shapes. A third band of light sources of a third colour may be provided at the central region of the flames. Of course, occasional light sources of the "wrong" colour may be interspersed in a band of generally one colour.

One or more groups of the light sources are preferably arranged to be switched on and off sharply, whilst one or more other groups are controlled so as to be fade on and off more gradually.

Preferably the display is adapted to produce a shooting flame effect in which a flame, or part of a flame, increases in height rapidly and then dies away again rapidly. The shooting effect may be provided at the uppermost tips of a flame, at the base of a display of flames (thereby comprising what is in effect a separate transient flame), or at any other part of the display. The shooting effect may be on a relatively few (for example one or two) light sources in width.

The display is preferably controlled by an electronic controller which may even cause the display to reproduce all or part of a life-cycle of a fire, from initial kindling to full burning to dying away to small flames or embers. The life-cycle may take several hours.

Preferably a coal or log, or other fuel, effect representation (such as a moulding) is provided adjacent the flame effect display.

The flame effect display may be provided at or behind the coal or log representation, preferably extending upwardly from it.

Alternatively, or additionally, a reflective member, such as a sheet may be provided to reflect light from the flame display towards the viewer, and may substantially cover the fuel effect.

Preferably the reflective sheet is transparent to enable a viewer of the fire to see the fuel effect.

The reflective sheet may be arranged relative to the flame effect display such that a viewer of the fire sees the flame effect reflected by the sheet. This can provide the appearance that the flame effect is generated at the fuel effect and gives a realistic simulation of burning fuel.

A viewer situated away from the fire may only be able to see the flame effect by means of the reflective sheet.

The reflective sheet may be a glass sheet. The arrangement of the reflective sheet may be as described in our published Patent Application No.GB 9001104.0, the contents of which are hereby incorporated by reference.

According to a second aspect of the invention we provide a fire having a display in accordance with the first aspect of the invention.

According to a third aspect of the invention we provide a method of imitating a flame effect comprising providing a plurality of light sources, and controlling the light sources so as to cause them to go on/go off in such a sequence as to reproduce a flickering flame.

The method preferably comprises controlling the light sources in groups and/or providing a diffuser screen. Different light sources preferably generate light of a different colour.

According to a fourth aspect of the invention we provide a fuel effect display comprising a representation of fuel lit from behind by a plurality of electrically powered light sources, the current to the light sources being controlled so as to cause the light sources to come on and go off in such a sequence as to reproduce pulsating, brightening and dimming, fuel.

Thus we reproduce the visual appearance of hot coal, logs, or the like by positively controlling the light sources, rather than simply having randomly flickering sources.

The representation of fuel is preferably three-dimensional, and may be a moulding.

According to a fifth aspect of the invention we provide a fire having a display in accordance with the fourth aspect of the invention.

According to a sixth aspect of the invention we provide a method of imitating burning fuel of a fire comprising providing a plurality of light sources behind a representation of fuel, and controlling the light sources so as to cause them to go on/go off in such a manner as to reproduce the visual effect of fuel glowing brighter and later dimming.

The fourth to sixth aspects of the invention may be used independently of the first to third aspects of the invention, or with them. The same electronic controller may control the light sources of the flames and of the fuel. Alternatively separate controllers may be provided.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings of which: Figure 1 schematically represents an electric fire having an electric flame effect display; Figure 2 illustrates schematically the layout of LED's on a display panel of the fire of Figure 1, showing the LED's in different groups; Figure 3 is similar to Figure 2, but shows the colours of the LED's; Figure 4 is a circuit diagram for the display of the fire of Figure 1, and Figure 5 schematically represents an alternative electric fire having an electric flame effect display An electric fire 20 is shown in Figure 1 and has a heating element (not shown), a coal-effect moulding 21, a flame-effect display 22, and a power supply 23 for the display 22.The display 22 comprises a printed circuit board 24 carrying a controller 25 and eighty LED's 26 and a diffuser screen 27.

The LED's 26 are laid out in the shape of five flames 28a to 28e and are controlled in twelve groups 1 to 12 as shown in Figures 2 and 4. The number of LED's in each of the groups 1 to 12 is shown in Figure 2.

LED'S of the groups 1 to 7, and 12, are present in more than one flame 28. LED's of the groups 8 to 11 are present in respective single flames only. Each LED 26 of a particular group is controlled by the controller 25 in the same way. It will be seen that many of the groups of LED's are interwoven on the display.

The controller 25 controls the LED's of groups 1 to 8 so as to change the light output from them relatively gradually (fade them in and out), but groups 9 to 12 are arranged to be switched on and off abruptly. This abrupt, sharp, switching simulates brief flickering or shooting, usually associated with the tops of flames. The more gradual changes of the heart of the fire are reproduced by groups 1 to 8.

Figure 3 shows the colours of the LED's 26. The LED's are, of course, represented by crosses and the colours by the letters 0 (Orange), R (Red), and Y (Yellow). The colours are predominantly in three horizontal bands, red, orange, and yellow as the height of the flame increases. There are exceptions to this general rule, such as the LED referred as 29 in Figure 3. It will be noted that some groups have LED's of more than one colour. For example, group 4 has seven red LED's and three orange LED's, and group 9 had three yellow LED's and two orange LED's.

Figure 4 shows the electronic circuit for the printed circuit board 24.

A mains transformer 30' steps the mains supply down to about 15.5V AC. The mains transformer is included in the power supply 23. A bridge rectifier 31' and smoothing capacitor 32 produce a fairly smooth DC voltage of about 15 volts to supply the LED's 26. A dropper resistor 33 and zener diode 34 provide a 5V rail for a microcontroller 35. This is smoothed by a capacitor 36 and protected against noise by a further capacitor 37.

The microcontroller 35 has a conventional reset circuit 38 and with protection against residual voltage on the capacitor being provided by a diode 39. A clock is provided by the RC circuit 40. The resistor of the RC circuit 40 could be replace by a potentiometer to give some speed variation of the flame effect. This speed variation could be manually controllable by the end user, or could be set upon manufacture of the fire.

Driver circuits 41 and 42 are used to provide increased voltage and current levels to the LED's. The LED's are supplied in fives, each set of five having a current limiting resistor 43. These sets of five are driven by the microcontroller. The resistors 43 need not all be the same, different value resistors can give different sets of LED's different intensities.

It will be appreciated that in the specific example described the groups 1-12 contain a integral number of sets of five LED'S.

The power supply 23 generates a 15.5v supply and may be mounted on the circuit board 24 if desired.

In operation, the controller 25 (comprising the microprocessor 35 and its associated driver circuits 41 and 42) switches on groups of LED's either individually or as combinations of more than one group. The described features are blended by the manufacturer through experimentation to combine to give the desired visual effect. The sequence of operation of the LED's can be quite long and complex and as such can mimic the variable intensity and vertical, and possibly horizontal, movement of a flame.

The precise switching details for the groups 1-12 are not central to the invention since deciding upon the group switching frequencies and order is a subjective exercise well within the capabilities of the skilled practitioner: what looks attractive to one man may not be quite right for another. However, the present invention allows us to mimic a real flame in that the apparent size of our flames 28a to 28e can be varied by turning on only the LED's at their lower, central, or upper regions, and their apparent intensity as seen by the user can be varied by having more or fewer of spatially adjacent groups of LED'S in a flame on simultaneously. For example, flame 28d will appear wider and brighter if groups 5, 8 and 10 are on, whereas if group 8 is off it will appear dimmer.

The diffuser assists this effect, and indeed the diffuser makes the fire look far more realistic than if we were to have the LED's viewed directly.

The flame-effect display 22 is mounted in the upper portion of the electric fire 20. The diffuser 27 is mounted to face generally downwards, towards a fuel display 30.

The fuel display 30 is in the lower portion of the electric fire 20 and is provided adjacent the moulding 21. A sheet of glass 19 is inclined at an angle in front of the moulding 21, and this sheet faces generally towards the flame effect display 22. The display 30 has an array of light sources 31, which may be LED's, but which are in this case light bulbs. The bulbs 31 are controlled by the controller 25 (or a separate controller) so as to come on and go off, and possibly to be at varying levels of brightness, so as to give the effect of the coals of the moulding 21 glowing more or less brightly. Different regions of the coals will, of course, glow more brightly than other regions at any one particular time, but at another moment the relative intensity of the two coal regions could be completely different, possibly even reversed.

The changes in the glowing "coals" may be arranged to be associated with corresponding changes in the flames of the display 22. For example, a particular coal may appear to glow brightly when a "shooting" flame appears above or near it.

When the two displays are in operation, an observer will be able to see clearly the moulding 21 through the sheet 19. The glowing "coals" will be visible. In addition the flame-effect produced by display 22 will be reflected to the observer by the sheet 19 and it will appear as though flames are dancing over the "coals" themselves. In this arrangement the flame-effect appears realistic.

The displays 22 and 30 may be separate integral units with their own electronic controllers so that a range of fuel displays and a range of flame displays could be used in a wide variety of combinations.

Figure 5 shows an alternative electric fire 20' which is similar to that of Figure 1 and similar structures have been given similar reference numerals.

The fire 20' has a fuel effect moulding 21' which is not covered by a sheet of glass and can be observed directly. A flame effect display 22' extends generally upwards from the rear of the moulding 21' so that flames can be seen above the moulding 21'. A diffuser 27' extends through, or is received in, a hole 21a in the moulding 21'. An observer of the fire 20' will see glowing coals provided by the fuel effect 30' with a flickering flame effect above the coals. It will be appreciated that the circuit board 24' and the arrangement of LED's 26' is as shown in Figures 2 to 4.

The fuel effect display 30' has an array of light sources 31', which may be LED's but which are in this case light bulbs. The bulbs 31' are controlled by the controller 23' (or a separate controller) so as to come on and go off, and possibly to be at varying levels of brightness, so as to give the effect of the coals of the moulding 21' glowing more or less brightly.

Different regions of the coals will, of course, glow more brightly than other regions at any one particular time, but at another moment the relative intensity of the two coal regions could be completely different, possibly even reversed. The changes in the glowing "coals" may be arranged to be associated with corresponding changes in the flames of the flame effect display 22'. For example, a particular coal may appear to glow brightly when a "shooting" flame appears above or near it.

The displays 22' and 30' may be separate integral units with their own electronic controllers so that a range of fuel displays and a range of flame displays could be used in a wide variety of combinations.

An example of the way that the control software (or hardware) for the flame effect could operate in either of the fires shown in Figure 1 or Figure 5 is as follows: The groups of LED's may have a main sequence cycle of about 250 (say 248) on/off patterns or states which the controller 25 cycles them through. A counter (not shown) counts down from 25 (giving 24 cycles to zero) and then introduces a "lull" in which the tips of some of the flames, say groups 8, 9 and 7, are not illuminated during the next cycle. The counter then resets to 25 and counts down again. Upon initial power up the counter is set to 2.

The controller 25 may include a test function to test that the board 24 is fully operative. This would be useful during the manufacture of the fire.

The fade feature described earlier can be achieved by transferring the on/off state data for some groups of LED (say groups 1 to 8) to one of a number (say 8) of registers. As a new illumination pattern is reached in the LED lamp sequence table it is fed into the first register, registers 2 to 8 holding the previous pattern. The controller controls the LED's to show the patterns of registers 1 to 8 in sequence for a time, so that the new pattern is shown initially for 1/8 of the time, and the old pattern for 7/8 of the time. Each time that the sequence 1 to 8 of the fade registers is complete the controller rolls the contents of the registers down one, so that on the second pass the ratio of new pattern to old pattern is 2: 6, on the third 3: 5, and so on.

The fade routine is used each time an LED in the group 1 to 8 changes from ON to OFF or OFF to ON producing a softening or glimmering effect.

There is, of course, a delay routine between execution of successive LED lamp patterns, so that the LED's stay fixed in a particular pattern for a predetermined time.

Claims

1. A flame effect display comprising a plurality of electrically powered light sources, the current to the light sources being controlled so as to cause the light sources to come on and go off in such a sequence as to reproduce a flickering flame.

2. A display according to claim 1 in which the light sources are arranged in the shape of at least one flame.

3. A display according to claim 2 in which the light sources are controllable so as to make the flame or flames increase or decrease in size.

4. A display according to any preceding claim which is provided with a diffuser screen in front of the light sources.

5. A display according to any preceding claim in which the light sources comprise one or more light sources of a first colour and one or more of a second colour.

6. A display according to claim 5 in which light sources of further colours are provided.

7. A display according to any preceding claim in which the light sources are controlled in a plurality of groups.

8. A display according to claim 7 in which one or more groups of the light sources are arranged to be switched on and off sharply and one or more other groups are controlled so as to fade on and off more gradually.

9. A display according to any preceding claim which is controlled by an electronic controller which causes the display to reproduce all or part of a life-cycle of a fire, from initial kindling to full burning to dying away to small flames or embers.

10. A display according to any preceding claim in which a fuel effect representation is provided adjacent the display.

11. A display according to claim 10 in which the display extends upwardly from the fuel effect representation.

12. A display according to claim 10 or claim 11 in which a reflective member substantially covers the fuel effect and is adapted to reflect light from the flame display towards a viewer.

13. A display according to claim 12 in which the reflective sheet is partially transparent to enable a viewer of the fire to see the fuel effect.

14. A display substantially as described herein with reference to Figures 1, 2, 3 and 5 of the accompanying drawings.

15. A fire having a display in accordance with any one of the preceding claims.

16. A fire substantially as described herein with reference to Figures 1, 2, 3 and 5 of the accompanying drawings.

17. A method of imitating a flame effect comprising providing a plurality of light sources, and controlling the light sources so as to cause them to go on/go off in such a sequence as to reproduce a flickering flame.

18. A method of imitating a flame effect according to claim 17 in which the light sources are adapted to be controlled in groups.

19. A method substantially as described herein with reference to Figures 2, 3 and 4 of the accompanying drawings.