GB2306636A

GB2306636A - Controlled Operation of Lamps

Info

Publication number: GB2306636A
Application number: GB9621710A
Authority: GB
Inventors: George Arthur Lapinski; David Anthony Hart
Original assignee: Ashley and Rock Ltd
Current assignee: Ashley and Rock Ltd
Priority date: 1995-10-20
Filing date: 1996-10-18
Publication date: 1997-05-07
Also published as: GB9621710D0; GB9521527D0

Abstract

There is disclosed a system for controlling two or more lamps to effect a desired illumination comprising a control device connected to each of the lamps to control them according to a control scheme stored in the control device, and a setting device connectable to the control device to predetermine the scheme to be stored in the control device and operable when so connected to control the lamps to vary the illumination to enable a desired illumination to be selected.

Description

CONTROLLING LAMPS This invention relates to controlling lamps and particularly, but not exclusively, to controlling the colour ofthe illumination of a scene, for example a display such as a shop window or interior display or for theatre, television or film set lighting.

Colour is conventionally controlled in such situations by mounting colour filters, usually gelatine filters, in front of white lamps, the filter colour being selected from a range of available filters to meet the requirements of the scene.

While this is a fairly straightforward approach, it requires, for reasonable flexibility, that a reasonably wide range of filters is available. The selection of the appropriate filter is usually a matter oftrial and error, which can be time consuming and, indeed, arduous when the filter has to be changed repeatedly on overhead lighting.

Moreover, particularly in regard to shop window illumination, ambient lighting can vary considerably - indeed from full sunlight to total darkness or street lighting - and the window lighting scheme for full sunlight will not be correct for overcast, dusk or dark conditions.

The present invention provides a system for controlling lamps that can be readily adapted to simplify considerably the setting up of a lighting scheme and also to vary the lighting either according to a predetermined regime or in accordance with changing ambient conditions.

The invention comprises a system for controlling two or more lamps to effect a desired illumination comprising a control device connected to each of the lamps to control them according to a control scheme stored in the control device, and a setting device connectable to the control device to predetermine the scheme to be stored in the control device and operable when so connected to control the lamps to vary the illumination to enable a desired illumination to be selected.

The system may be adapted for controlling the relative brightness of the lamps and in particular may be adapted for controlling the relative brightnesses of lamps of different colour.

The control scheme may be a static scheme. The control device may store a plurality of schemes, and may have a selector mechanism by which a control scheme may be selected from a plurality of stored schemes.

The control scheme may be a dynamic scheme in which the desired illumination varies over time - this may involve switching between static control schemes, or it may, of course, involve a single continuously variable control scheme operative in the time domain.

Control schemes, whether static or dynamic, may be stored as coded signals in programmable read only memory (PROM) - usually, of course, this is electronically programmable, erasable memory (EPROM).

The setting device may comprise ajoystick arranged to control the lamps, and may be operable to create a control scheme, store the control scheme in the control device and select which of a plurality of control schemes stored in the control device will be operative. The setting device may have a numeric keypad operable to assign codes to control schemes, and may have a visual display unit (VDU), which may comprise a numeric or alphanumeric display and/or a graphics display, which may be a liquid crystal display.

The setting device may be operable to adjust the control scheme according to a selected one of a plurality of algorithms.

The setting device may be operable to adjust the control schemes according to a linear algorithm by which relative adjustment between any two or more lamps is such that the sum oftheir intensities is constant. The setting device may, on the other hand, be operable to adjust the control scheme according to a Pythagorean algorithm, by which relative adjustment between any two lamps is such that the sum ofthe squares of their intensities is a constant.

In what is expected to be the usual form ofthe system, three lamps will be used, one of each of the three primary colours red, green and blue. These may be arranged, in relation to a joystick or like controller that they emulate the familiar CIE chart, with green at the top, blue bottom left and red bottom right of a triangular configuration, that is to say, moving the joystick northwards intensifies green, south westwards intensifies blue and south eastwards intensifies red.

The setting device may be operable to adjust the control scheme according to a linear algorithm by which the relative adjustment between any two or more lamps is such, for a linear movement of the joystick, that the sum of their intensities is constant.

Or it may be operable to adjust the control scheme according to a Pythagorean algorithm by which the relative adjustment between any two lamps is such for a linear movement of the joystick that the sum of the squares of their intensities is constant. In such an arrangement, a linear relationship (i.e. constant intensities sum) can be achieved but by a curvilinear joystick motion with increased sensitivity towards the middle of the simulated CIE chart.

While three primary colours for the lamps will be a normal arrangement (except, clearly, for special purpose arrangements in which a restricted colour range is all that will be required) it may also be quite usual to have an additional white light which will more easily give pastel hues. The white light can be independently adjustable.

In addition to colour control, of course, the intensities of all of the lights can be commonly adjusted to vary total light intensity, and this can be effected while maintaining the same colour balance. Particularly in that regard, it is of interest to note that the relationship between a lamp's output intensity and its controlling signal may not be linear - this is clearly the case in voltage control of an incandescent lamp, and a transfer function may be incorporated that linearises the response of one or more of the lamps. Any suitable form of control may be used, for example rapid pulsing with control of mark/space ratio, especially in the case of laser lights.

The control unit may have an ambient light sensor and control the lamps in accordance with ambient light - this may be a simple accommodation control to maintain a desired colour balance - the brighter the ambient light, the brighter the lamps, for example, - or it might be compensating- the darker the ambient conditions the brighter the lamps - or it might be adaptive, for example changing the colour control scheme when ambient changes from daylight to, for instance, sodium or mercury vapour street lighting, to keep a constant appearance.

The control unit may of course have a timer, as well as a fade control, with controllable fade rate, for cycling between colour schemes in a desired way.

For a window or in-store lighting arrangement, three lamps, which may be quaaa:-haiogen low voltage lamps fitted with dichroic filters, may be installed in a "tower" with an optional white lamp. A connection port will be provided for a flying lead from a setting device. For a stage lighting system a bank of three (RBG) or four (RBG + white) lamps may be left more or less permanently in place, perhaps with a remote directional controller, and a radio or infra red link to a setting device or even be set through signals from a setting device sent as pulse codes along the power cabling to the lighting bank - a single setting device could serve all the theatre lighting, by each lighting bank having an address code.

Embodiments of systems for controlling lamps according to the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a lighting "tower" suitable for use a shop window or in-store lighting; Figure 2 is a diagrammatic illustration of a lighting bank for a theatre or a television or cine film set; Figure 3 is a view of a setting device for use with the lighting tower or lighting bank of Figures 1 and 2.

The drawings illustrate systems for controlling lamps 11 to effect desired illumination. Figure 1 illustrates a lamp "tower" 12, which might be, say, a metre of so high and be suitable as a shop window or in-store lighting unit intended to show off products in, literally, the best possible light.

The colour temperature ofillumination is of great importance in the display of goods for sale, particularly textiles, whether clothing or household fabrics, and foodstuffs. Illumination with a selected colour balance can create effects ranging from restful to dramatic. The tower 12 of Figure 1 is capable of providing a complete range of lighting effects and, together with the complementary parts of the system described below, of rapidly establishing the optimum lighting for any situation and of maintaining lighting at its optimum, through various changes in ambient conditions.

Likewise the theatre, television or film set lighting bank 13 of Figure 2 is capable of providing a full range of effect lighting, and, again, in combination with other parts of the system, of enabling the lighting director to establish readily the optimum lighting specification for any desired theatrical effect and to reproduce the same once established and even to vary the same to compensate for ambient conditions or for colour balance drift in video and broadcast equipment.

Any other kind of controllable light can be used, such as flourescent tubes..

If a lamp is inherently uncontrollable, control can always be effected mechanically as by a variable aperture diaphragm or "barn doors".

The lamps 11 are, in each case, four in number, comprising green 11G, blue, 1 1B, red 1 1R and white 11W lamps, the colours deriving, in Figure 1 from dichroic filters 14 in front of low voltage quartz halogen lamps and, in Figure 2, from gelatine filters.

The lamps 11 of Figure 1 are mounted in eyeball mounts for manual pointing, although they could clearly be fitted with directional controls in a more comprehensively controlled arrangement, or, for certain less critical requirements, simply be fixed floodlights.

Each lamp 11 is controlled as to its intensity or brightness by a controller 15, these being labelled 15G, 15B, 15R and 15W corresponding to the lamps.

The controllers 15 are pulsing controllers pulsing the d.c. driving current to the lamps 11, varying the intensity or brightness thereof by varying the mark/space ratio of the pulsing. Of course, any other arrangement - a simple rheostat control arrangement, for example - could be used instead, but that would be less efficient and generate more waste heat.

The controllers 15 are, in their turn, controlled by a control device 16, which would normally comprise a programmable or instructable microprocessor and which contains the basic instructions for controlling the controllers 15. In fact, the control device 16 can hold in memory (which for practical purposes is going to be nonvolatile memory such as EPROM or battery-backed RAM) a whole set of control schemes from which any one, or any sequence, which may be a looping sequence, can be selected to operate.

Just as a simple example of what is meant by a control scheme may be mentioned that the lamps 11 operate with relative intensities as follows: llG 0.4 liB 0.25 11 R 0.31 11W 0.14 which will give a predominantly green cast to any scheme that is so illuminated.

The control device 16 may hold many such sets of ratios in memory and any one may be selected to instruct the controllers 15 at any time to control the lights 11 to produce the corresponding illumination. Such selection may be effected by a switch or keypad selector 17 connected to the control device 16 or by an internal clock in the device 16 when that device is suitable programmed or instructed, or by an ambient light monitor 18 (set so as not to be affected by the light emitted by the lamps 11) or by a feedback mechanism which involves red blue and green sensors 19 sensing the effect, for example on a shop window display, of the illumination provided by the lamps 11.

Information input to the control device 16 is via a port 21.

Figure 2 illustrates a theatre lighting bank 13 of the kind which is carried high above the stage or set. In general, from a control point of view, it is similar to the lighting tower 12 of Figure 1 in having a control device 16. In addition, however, it also has remote movement control, for example by an on-board electric motor 22 for tilt in yolk 23 for tilt, and also for panning about a suspension axis 24 by means of another motor 25. Both motors 22 and 25 can be controlled from the setting device to be described below with reference to Figure 3 which, however, is primarily for controlling the colour ofthe illumination provided either by the tower 12 of Figure 1 or the lighting bank 13 of Figure 2.

The setting device 31 of Figure 3 is connectible by flying lead 32 to the port 21 ofthe tower 12 of Figure 1. Similar connection can be made to a lighting bank 13 as illustrated in Figure 2 but it is probably more practical to have a wireless e.g. radio or IR connection or to send coded pulse signals electronically via the electric power cabling.

The setting device 31 comprises a casing affording a setting console sporting a joystick 33 and a numeric keypad 34 as well as an on/off switch 35 and a visual display unit (VDU) 36.

The keypad 34 is used for a number of purposes, as will be presently explained.

The joystick 33, which could, of course be substituted by any comparatively functional device (for example, a set of directional keys of the kind used for cursor control in computer key boards) is primarily used to control the lamps 11 when connected to the tower 12 or bank 13.

As indicated on Figure 3, while the joystick 33 has all the usual joystick movements, movement in a northwards direction increases the "G" or green intensity, movement in a south westerly direction increases "B" or blue intensity, while movement in a south easterly direction increases "R" or red intensity. This arrangement mimics the CIE colour chart and intermediate positions of the joystick 33 corresponds to relative intensities of the lamps 15G, 15B and 15R which will yield the colours of the chart.

With the setting device connected to the lamps 11, the joystick 33 can be adjusted until a desired effect is produced by the lamps 11.

The keypad 35 then comes into play to a) establish (e.g. by pressing "11") a "store" mode and b) assign a memory address, by pressing two further numbers (e.g.

"36"), in the control device 16 whereupon in that address the coordinates specifying the joystick position are stored, which coordinates correspond to signals setting up a particular relative intensity of"R", "B" and "G" light.

Further the keypad or a separate slide switch can be used to control the level of white light from lamp 11W, and this valve may also be stored in the control device 16.

The VDU can indicate the values and/or effects of keypad operations and can also give a graphical representation of the position of the joystick 33.

In this way, the system can be used to establish and record a number of control schemes, and record them in the control device 16. Such schemes may be static schemes, corresponding to a single position of the joystick, but may also be dynamic schemes. For example, the joystick may be moved around over a period of time, its movements digitised and stored as a sequence of instructions representing a smoothly varying colour sequence from e.g. red to green to blue to green to red and so forth.

Thejoystick movements may have different effects according to a selection of operational modes ofthe system. For example, a simple operational mode would have the intensity of each lamp linearily dependent on the coordinates of the joystick. Thus, if the joystick were placed as far north as it would go, the green light 116 would be extinguished and the blue and red lights 11B, 11R would be lit in proportion to the position of the joystick between the southwest and southeast extreme positions.

Such a regime would effectively keep total illumination intensity constant, though the relative intensities of each colour would vary according to the position of the joystick.

Another modus operandi uses a Pythagorean algorithm in which the intensity of each lamp depends on the square of the distance of the joystick from a null (or equal) position which may be central, but does not have to be. The same, or essentially the same effect will be obtained, namely that the intensity of the lamps will vary as the joystick is moved, but the sensitivity ofthe joystick will be affected and may be enhanced in certain areas of its movements, and the total intensity may also change, all depending upon the parameters attached to the algorithm.

Lamps, especially incandescent lamps, may be responsive non-linearly to driving voltage or even to mark/space control pulsing, and may need to be linearised by the use of a transfer fimction modifying the signal from the joystick.

Fade, rate of fade, cycling and many other features can be built, whether in hardware, firmware or software, into the system.

Although primarily described with particular reference to the colour, the invention could also be used in connection with radiation out with the visible spectrum, for example IR or UV radiation and, while reference has been made primarily to colour in the context of commerce - window dressing - and entertainment, it is clear that there would be opportunities to utilise the underlying principles in other fields of endeavour.

Whilst we have described a dedicated setting device it will be understood that such might be programmed and comprised by a computer suitably controlled with ajoystick, mouse or cursor keys.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof.

Claims

1. A system for controlling two or more lamps to effect a desired illumination comprising a control device connected to each ofthe lamps to control them according to a control scheme stored in the control device, and a setting device connectable to the control device to predetennine the scheme to be stored in the control device and operable when so connected to control the lamps to vary the illumination to enable a desired illumination to be selected.

2. A system according to claim 2, adapted for controlling the relative brightnesses ofthe lamps.

3. A system according to claim 1 or claim 2, adapted for controlling the relative brightnesses of lamps of different colour.

4. A system according to any one of claims 1 to 3, in which the control scheme is a static scheme.

5. A system according to any one of claims 1 to 4, in which the control device stores a plurality of control schemes.

6. A system according to claim 5, in which the control device has a selector mechanism by which a control scheme may be selected from the said plurality of stored schemes.

7. A system according to any one of claims 1 to 6, in which the control scheme is a dynamic scheme in which the desired illumination varies over time.

8. A system according to claim 6, in which the dynamic control scheme involves switching between static control schemes.

9. A system according to any one of claims 1 to 7, in which the control schemes are stored as coded signals in programmable read only memory (PROM).

10. A system according to any one of claims 1 to 8, in which the setting device comprises ajoystick arranged to control the lamps.

11. A system according to any one of claims 1 to 9, in which the setting device is operable to create a control scheme, store the control scheme in the control device and select which of a plurality of control schemes stored in the control device will be operative.

12. A system according to any one of claims 1 to 11, in which the setting device has a numeric keypad operable to assign codes to control schemes.

13. A system according to any one of claims 1 to 12, in which the setting device has a visual display unit (VDU).

14. A system according to claim 13, in which the VDU comprises a numeric or alphanumeric display.

15. A system according to claim 13 or claim 14, in which the VDU comprises a graphics display.

16. A system according to any one of claims 1 to 15, in which the setting device is operable to adjust the control scheme according to a selected one of a plurality of algorithms.

17. A systems according to any one of claims 1 to 16, in which the setting device is operable to adjust the control scheme according to a linear algorithm by which relative adjustment between any two or more lamps is such that the sum of their intensities is constant.

18. A system according to any one of claims 1 to 17, in which the setting device is operable to adjust the control scheme according to a Pythagoras algorithm by which relative adjustment between any two lamps is such that the sum ofthe squares of their intensities is constant.

19. A system according to any one of claims 1 to 18, in which three lamps are used, one of each of the three primary colours.

20. A system according to any one of claims 1 to 19, in which a white light is used in addition to at least one coloured light.

21. A system according to any one of claims 1 to 20, in which the intensities of all the lamps can be ramped up and down together.

22. A system according to any one of claims 1 to 21, in which a transfer function linearwise the response of any one or more lamps.

23. A system according to any one of claims 1 to 22, in which the control unit has an ambient light sensor and controls the lamps in accordance with ambient light.

24. A system according to any one claims 1 to 23, having a fade control.

25. A system according to claim 24, in which fade rate is controllable.