EP0219255B1

EP0219255B1 - Improvements in luminaires

Info

Publication number: EP0219255B1
Application number: EP86307440A
Authority: EP
Inventors: Brian Morgan
Original assignee: WHITECROFT PLC
Current assignee: WHITECROFT PLC
Priority date: 1985-10-08
Filing date: 1986-09-29
Publication date: 1993-02-03
Anticipated expiration: 2006-09-29
Also published as: EP0219255A3; DE3687685T2; ATE85413T1; EP0219255A2; DE3687685D1

Abstract

A luminaire using a reflector system comprises a first reflective upper region (4) which is designed to reflect light from a light tube (2) and a second reflective lower region (6) having lower luminance than the upper region. The upper and lower regions are interconnected by an intermediate region (5) having a reflecting surface which has an effective luminance between the luminance of the said upper and lower regions. The upper, intermediate and lower regions (4, 5, 6) may be provided on a pair of reflector strips which are installed in a housing (1) containing the light tube (2), the strips extending substantially the length of the light tube. The intermediate region (5) of each strip may be provided by forming this section of each strip with a wider angle to the vertical than either the upper region (4) or the lower region (6). Alternatively, the intermediate region (6) may be formed by providing this section of each strip with a colouring effect which is between the colouring effects of the upper and lower regions in order to achieve the intermediate luminance. Each strip is desirably made of aluminium or an aluminium alloy, the upper region (4) and the inner surface (3) of the housing (1) being painted white and the lower region (6) being left uncoloured. The intermediate region (5) may be painted white, grey or with various pattern effects to achieve the desired intermediate luminance.

Description

This invention relates to light fittings and is particularly concerned with luminaires using reflector systems which incorporate one or more fluorescent lighting tubes. Such a luminaire has for instance been disclosed in US-A-4.536.830.
A current trend is to design overhead fluorescent luminaires with a reflector system to obtain the highest possible direct ratio in pursuit of maximum energy effectiveness. By "direct ratio" is meant the proportion of light directly reaching the working plane to the total emitted by the luminaires.
The reflectors are generally of specular (mirror finish) electro-brightened aluminium and often wrap completely around the tube. Crossblades to give axial light control used to be made of a specially extruded aluminium section designed to have a low brightness. Today an increasing number of reflectors have fabricated curved wedge-shaped crossblades of reflector material. These crossblades ensure a low brightness view from all directions around the luminaire.
The use of specular reflector material gives the luminaire a "dark hole" appearance from distant viewing angles: indeed the luminaire does not appear to be lit at all. An alternative is to use more commercial grades of reflector material which have brushed or lustre finishes. This type of finish gives the luminaire some luminosity so that the luminaire appears to be lit. It is said that room users prefer to see where the lighting actually comes from, so the lustre material would seem to be a better choice.
Regardless of the type of reflector material, the modern luminaire has a wide light distribution and a sharp cut-off. The sharp cut-off prevents a direct view of the tube at long viewing angles and theoretically gives a good control of glare. Indeed, these luminaires are often referred to as "low brightness".
The wider distribution is necessary to ensure adequate vertical illuminance which gives better modelling and better inter-reflection of light around the space - to give the space the appearance of being properly illuminated. However to achieve this the room reflecting surfaces must be light.
The modern reflector luminaire has serous faults which are generally ignored if the design criteria of high direct ratio and energy effectiveness have been achieved. The use of computers and VDU's in offices has further complicated the situation but provided that the luminaire conforms with the cut-off recommendations of current lighting codes such as the CIBSE memorandum TM6 entitled "Lighting for Visual Display Units" the specifier is satisfied.
The introduction of the T8 tube has made matters worse. With this tube it is easier to direct light but reflector contours are now much more critical and small changes of contour or of tube position produce large changes in light distribution. Distributions are more peaky, particularly if they are "batwing". The result is a distribution that is so strongly directional that modelling is over-emphasised and very strong. Much higher tube luminance strengthens the modelling, but also ensures that reflected highlights in the space (sparkle) are now over bright, if not glaring.
The strong modelling and contrasts and the dark shadows and over bright highlights result in the lighting being very hard, harsh and unflattering. If the room surface reflectances are low, not only will the "low brightness" luminaire glare because the ceiling will be rather dark, but the interior will be uncomfortable and unpleasant to work in.
There are other defects. If, when we raise our eyes from a desk to rest them and gaze at the horizon, we can see in the periphery of our vision the reflector flash at the angle of peak intensity, we experience what has been termed "nose glare". The effect is worse when seated with a modern reflector luminaire at right angles to the direction of gaze and slightly ahead of the viewer's position. Often one senses energy rather than light being radiated to one's forehead but either way the effect is rather uncomfortable and is certainly disturbing.
Moving one's gaze above the horizontal can be equally uncomfortable. If one casually glances into a modern reflector luminaire the high brightness "flashed" reflector areas will be seen adjacent to dark unflashed areas or against a dark ceiling. The contract will be high and the flashed area will appear excessively bright and glaring. If the bare tube is also visible against an unlit background, as it would be with a double or wrap-around reflector system, the discomfort will be much worse. Looking into a reflector luminaire is not usually a deliberate act; it is usually casual. Often, like "nose glare" one is conscious of the high brightness in the periphery of one's vision.
The sharp cut-off itself can be very annoying. In installations with low ceiling heights and with luminaires at maximum centres (whilst the illuminance at working plane level will be designed to be even) the illuminance at higher levels will vary. Because the cut-off is sharp and the lighting strongly directional, a person walking through the space will find the lighting very odd, for he will experience alternate zones of light and shadow whilst the floor will appear evenly lit.
Then there is the ladder effect. In wedge-shaped crossbladed luminaires, irrespective of whether the top of each blade is open or closed, the illuminated top and inside of the wedge-shaped crossblades will be reflected in the side reflector at angles above the cut-off angle. These reflection will appear as a series of bright vertical bars forming a ladder lying on its side. The wider the reflector and the shallower the edge-shaped crossblades, the worse the effect, which is very annoying and often downright disturbing. In any event the high brightness flash is visible above the declared cut-off angle. The defect can be avoided by special blade design, but all too often the user has to put up with the fault in the interests of lower costs.
Finally, there is the simplistic acceptance that screen reflection is a problem to be solved with VDU lighting. This has led to a collapse of the wide distribution of modern luminaires and all other considerations of good lighting are ignored. Modern VDU luminaires look distinctly similar to the high direction ratio "low glare" luminaires of 20 years ago. The distribution is similar, the modelling and highlights are much stronger, inter-reflection is poor and horizontal surfaces still tend to glare.
The modern reflector luminaire needs a complete re-design to eliminate the defects. The distribution needs to be broad and without significant peaks. It should be softer, more diffuse, with controlled light at higher angles. The cut-off should be less pronounced which will improve the visual appearance of the space. There should be more inter-reflection of light within the space and highlights should be reduced so that contrasts will be softer and the hard appearance of the lighting will have gone.
The present invention therefore aims to provide a luminaire for a reflector system which eliminates the above-mentioned defects of existing luminaires.
According to the invention, there is provided a luminaire with a reflector system which is designed to reflect light from a light tube and which extends substantially the length of the light tube, the reflector system comprising two reflector parts at both sides of the tube and each part comprising a first reflective upper region beside the tube and a second reflective lower region having lower luminance than the upper region, wherein the said upper and lower regions are interconnected by an intermediate region having a reflecting surface which has an effective luminance between the luminance of the upper and lower regions.
The upper region of the reflector should desirably be located above and to one side of the light tube.
The luminaire according to the invention may comprise a housing containing the light tube and two strips arranged to be located on either side of the light tube, the strips extending substantially the length of the light tube and each strip comprising an upper region and a lower region interconnected by an intermediate region having intermediate luminance. The upper region, intermediate region and lower region of each strip may be provided on a single integral component which may take the form of an arcuate strip.
Alternatively, the luminaire according to the invention may comprise a housing containing the light tube but in which at least the said upper region constitutes part of the housing, the lower region being provided on two strips arranged in the housing and extending substantially the length of the light tube, each strip being connected to the housing and spaced from the upper region by said intermediate region having intermediate luminance.
In either case, the upper region and intermediate region may be formed as an integral component and the lower region formed as a separate strip.
Alternatively, the lower region and intermediate region may be formed on a single strip as an integral component which is secured to the housing.
As a further alternative, the upper region, intermediate region and lower region are formed as separate components, each connected to the housing.
According to one embodiment of the invention, the said upper and lower regions are interconnected by an intermediate region having a reflecting surface which extends outwardly from the first upper region at a shallower angle so that its effective luminance is between the luminance of the said upper and lower regions. The upper region is desirably inclined at an angle of between 40° and 45° to the vertical, the lower region desirably extends at a narrower angle to the vertical than the upper region, preferably less than 20°, and the intermediate region desirably extends at a wider angle to the vertical than the upper region, preferably about 65°.
The strips may be interconnected, at intervals, by crossblades, which are preferably wedge-shaped.
Preferably, the upper region is white while the lower region is desirably made of aluminium or an aluminium alloy which is uncoloured.
In the case in which the intermediate region extends at a shallower angle to the vertical than the upper region, the intermediate region may also be coloured white. However, in all cases, the intermediate region may be partially coloured white and the white colouring may take the form of spots or lines or a zig-zag formation. Where spots or lines are used, these preferably increase in size and/or number from the lower region towards the upper region. As a further alternative, the intermediate zone may be coloured grey, the grey colouring, which may be paint, preferably getting progressively darker from the upper region to the lower region.
By using a white reflector behind and to the side of the light tube, the tube is not visible against a dark unflashed reflector but it blends into the background and is more comfortable to look at. However, if there were a simple direct transition between the highly reflective upper region and lower reflective lower region, as disclosed for example in the already mentioned US-A-4536830, the view of the reflector at long viewing angles would be glaring because the upper region would be seen adjacent to the much darker lower region with a luminance ratio of over 25:1. By providing the intermediate region of intermediate luminance to give a so-called intermediate brightness zone, the glaring contrast between the light and dark regions of the reflector is reduced and a casual view inside the reflector is now very comfortable.
The luminance of the crossblades and of the lower regions of the reflector strips is preferably of the order of 200 cd/m² and the luminance of the intermediate region is desirably arranged to be midway between this luminance and the luminance of the upper region of the reflector. With this arrangement, the long angle view of the luminaire, all round, is low brightness and less than 200 cd/m² luminance.
The invention will now be further described, by way of example, with reference to the drawings, in which:-

Fig. 1 is a perspective view of one end of a luminaire having a reflector according to the invention.
Fig. 2 is a diagrammatic cross-section through the luminaire shown in Fig. 1 to illustrate more clearly the angles of the various regions or zones of the reflector;
Fig. 3 is a diagrammatic cross-section through the right half of a luminaire according to the invention showing a modification;
Fig. 4 is a diagrammatic cross-section through the left half of another modification of a luminaire according to the invention;
Fig. 5 is a diagrammatic cross-section through the right half of a luminaire showing a modification of the example illustrated in Fig. 4;
Fig. 6 is a diagrammatic cross-section through the left half of a luminaire showing a further modification of the examples illustrated in Figs. 4 and 5;
Fig. 7 is a diagrammatic cross-section through the right half of a luminaire showing a still further modification of the example illustrated in Fig. 6;
Fig. 8 is a diagrammatic cross-section through the left half of another embodiment of a luminaire according to the invention.
Fig. 9 is a diagrammatic cross-section through the right half of a modification of the luminaire shown in Fig. 8;
Fig. 10 is a diagrammatic cross-section through the left half of a still further embodiment of a luminaire according to the invention.;
Fig. 11 is a diagrammatic cross-section through the right half of a modified form of the luminaire shown in Fig. 10;
Fig. 12 is a perspective view of one end of a luminaire according to the invention having yet another embodiment of reflector system;
Fig. 13 is a perspective view similar to Fig. 12 but showing a still further embodiment of reflector system;
Fig. 14 is a perspective view similar to Figs. 12 and 13 but showing a further embodiment of reflector system;
Fig. 15 is a perspective view similar to Figs. 12 to 14 but showing another embodiment of reflector system;
Fig. 16 is a perspective view similar to Figs. 12 to 15 but showing yet another embodiment of reflector system;
Fig. 17 is a perspective view similar to Figs. 12 to 16 but showing a still further embodiment of reflector system;
Fig. 18 is a diagrammatic section through any of the luminaires shown in Figs. 12 to 17 to illustrate more clearly the disposition and shape of the reflector;
Fig 19 is a diagrammatic section of the right half of a luminaire, corresponding to Fig. 18, but showing a modification of the reflector strip;
Fig. 20 is a diagrammatic section through the left half of a luminaire showing a modification of the reflector strip shown in Fig. 19;
Fig. 21 is a diagrammatic section through the right half of a luminaire but showing a further modification of the reflector strip shown in Fig. 20;
Fig. 22 is a diagrammatic section through the left half of a luminaire showing a still further modification of the example illustrated in Fig. 20:
Fig. 23 is a diagrammatic section through the right half of a luminaire showing another modification of the example illustrated in Fig. 22;
Fig. 24 is a diagrammatic section through the left half of still another embodiment of a luminaire according to the invention;
Fig. 25 is a diagrammatic section through the right half of a modification of the luminaire shown in Fig. 25;
Fig. 26 is a diagrammatic section through the left half of a further modification of the luminaire shown in Fig. 25; and
Fig. 27 is a diagrammatic section through the right half of a modification of the luminaire shown in Fig. 26.

In the drawings, like parts are denoted by like reference numerals.
Reference will first be made to Figs. 1 and 2 of the drawings in which the luminaire comprises a body or housing 1 which is adapted to be fitted to a ceiling by suitable means (not shown). The body 1 is of channel section and is provided with suitable mountings (not shown) for receiving and holding a fluorescent light tube 2. The surface 3 of the body 1 is preferably painted white to serve as a reflective surface. Mounted on each side of the body 1, within the channel, is a respective reflector strip, each strip comprising an upper region 4, a lower region 6 and an intermediate region or zone 5.
As can be seen more clearly from Fig. 2, the upper region 4 of each reflector strip is inclined to the vertical at an angle of about 40°, the lower region 6 is inclined to the vertical at a smaller angle of less than 20° and the intermediate zone 5 is inclined to the vertical at a wider angle of about 65°.
The two reflector strips are interconnected, at spaced intervals, by wedge-shaped crossblades 7 each of which is secured, at its ends, to the lower regions 6 of the respective reflector strips. The reflector strips may be secured to the housing 1 by any suitable means known in the art.
The upper regions 4 and the intermediate zones 5 of the reflector strips are provided with a highly reflective white coating - preferably white gloss paint. The lower regions 6 and the crossblades 7 are desirably made of aluminium or aluminium alloy which is unpainted. Each reflector strip may therefore be made from a length of extruded aluminium or aluminium alloy which is painted white in the areas which will form the upper region and intermediate zone and then cut to the desired length for use with a light tube for which the reflector is intended.
Fig. 3 shows a modification in which the lower region 6a is made from a first strip of unpainted aluminium or aluminium alloy and the upper region 4a and intermediate region 5a are made from a second strip which is painted white and which is made of aluminium, aluminium alloy or other suitable metal. This second strip has a further section 8 extending at substantially the same angle as the lower region 6a. The first strip can thus be secured by suitable means (not shown) to the section 8 of the second strip.
In the modification shown in Fig. 4, the lower region 6b is again made from a separate strip but in this case, instead of being secured to a strip carrying the intermediate and upper regions, the strip, which is provided with an L-sectioned flange 9, is simply secured by means of this flange to a side wall 10 of the housing 1. The upper region 4b and intermediate region 5b are provided on a strip having a section 11 which is secured to the surface 3 of the housing 1 by suitable means (not shown). In this case, the section 11 will be painted white so as to form a substantially continuous reflective surface with the surface 3.
Fig. 5 shows a similar arrangement to that of Fig. 4 but in this case the upper region 4c and intermediate region 5c are provided on a strip having an L-shaped section 12 which is secured to a side wall 10 of the housing 1, the section 11 being omitted. With this arrangement, wiring 13 may be carried in the housing above the section 12.
Fig. 6 shows a further modified arrangement which is similar to the arrangements shown in Figs. 4 and 5 except that in this case the upper region 4d is provided on a separate strip having a section 11 which is secured to the surface 3 of the housing 1 and the intermediate region 5d is provided on a further separate strip having an L-shaped section 12 which is secured to the side wall 10 of the housing.
A further modification is shown in Fig. 7 in which the intermediate region 5e is provided on a separate strip as in Fig. 6 but in this case the region 5e extends to the side wall 10 of the housing 1 and is secured to the said side wall by a section 14 of the strip which is inclined at an angle to the region 5e and extends substantially parallel to the side wall 10.
The luminaire shown in Fig. 8 differs from the previous examples in that, in this case, the housing 1 is provided with inclined walls 15, the inner surface of which constitutes the upper reflective region 4e. The intermediate region 5f and the lower region 6c are provided on a single strip provided with an L-sectioned flange 9 by means of which the strip is secured to the side wall 10 of the housing 1.
Fig. 9 shows a modification of the example shown in Fig. 8 in which the intermediate region 5g and the lower region 6b are provided on separate strips, the strip having the intermediate region 5g being provided with a section 16 by means of which the strip is secured to the strip having the lower region 6b.
A further embodiment of a luminaire is shown in Fig. 10 of the drawings in which, in addition to having inclined walls 15, the housing 1 is provided with further inclined walls 17. The walls 17 extend at a shallower angle than the walls 15 and their inner surfaces constitute the intermediate region 5h while the inner surfaces of the walls 15 constitute the upper reflective region 4e. The lower region 6b is provided on a separate strip which is secured to the side wall 10 of the housing 1 by the section 9 as before.
The luminaire shown in Fig. 11 is similar to that shown in Fig. 10, merely differing in the shape of the housing.
The luminaire shown in Figs. 12 to 18 of the drawings is similar to the previous embodiment in that it comprises a body 1 which is adapted to be fitted to a ceiling by suitable means (not shown), is of channel section and is provided with suitable mountings (not shown) for receiving and holding a fluorescent light tube 2. The surface of the body 1 is preferably painted white to serve as a reflective surface. Mounted on each side of the body 1, within the channel, is a respective reflector strip 18 which comprises an upper region 4, a lower region 6 and an intermediate region or zone 5. In the case of Figs. 12 to 18 however, the reflector strips are arcuate.
The two reflector strips are interconnected, at spaced intervals, by wedge-shaped crossblades 7 each of which is secured, at its ends, to the lower regions 6 of the respective reflector strips.
The upper regions 4 and the intermediate zones 5 of the reflector strips are provided with a highly reflective white coating - preferably white gloss paint - which may be applied by a screen-printing process although any other suitable process may be employed if desired. The lower regions 6 and the cross blades 7 are desirably made of aluminium or aluminium alloy which is unpainted. Each reflector strip may therefor be made from a length of extruded aluminium or aluminium alloy which is painted white in the areas which will form the upper region and intermediate zone and then cut to the desired length for use with a light tube for which the reflector is intended.
The reflector strips may be secured to the body 1 by any suitable means (not shown) known in the art.
The intermediate zone 5 of each reflector strip may be created by the application of white paint in various forms. In the embodiments shown in Figs. 12 and 13 a series of spots or dots are painted onto the reflector strip. In Fig. 12, the spots or dots are arranged in rows and increase in size from the lower region 6 to the upper region 4 of the reflector strip whereas in Fig. 13 the spots or dots are all of the same size but are spaced relatively far apart in a row adjacent to the lower region 6 and are spaced progressively closer together in adjacent rows in a direction towards the upper region 4 of the reflector strip.
In the embodiments shown in Figs. 14 and 15, a series of substantially parallel lines are painted onto the reflector strip. In Fig. 14, the width of the lines and the spacing between them is progressively reduced from the lower region 6 to the upper region 4 of the reflector strip whereas in Fig. 15 the width of all of the white lines is substantially the same but the spacing between them is progressively reduced from the lower region 6 to the upper region 4 of the reflector strip.
In the embodiment shown in Fig. 16 of the drawings, a series of wedges are painted onto the reflector strip at the intermediate zone 5 to form a zig-zag formation at said zone.
In the embodiment shown in Fig. 17, the intermediate zone 5 consists of a single band of lower luminance than the upper region 4 of such a colour or texture that it has a luminance which is between that of the higher luminance region 4 and the lower luminance region 6.
The reflector strips 18 may each consists of a single arcuate component as shown in Fig. 18 of the drawings. Modifications are, however, possible within the scope of the invention and the strip 18 need not be arcuate. One such modification is shown in Fig. 19 in which the reflector strip consists of a single planar strip 19.
Fig. 20 shows a further modification in which the reflector strip consists of a first strip 21 on which the upper region 4 and intermediate region 5 are provided and a second strip 22 on which the lower region 6 is provided. The strip 21 is provided with a section 11 by means of which it can be secured to the surface 3 of the housing 1 and the strip 22 is provided with an L-sectioned flange 9 by means of which it is secured to a side wall 10 of the housing. In this case, the section 11 will be painted white so as to form a substantially continuous reflective surface with the surface 3.
Fig. 21 shows a similar modification but in this case the upper strip 21 is provided with an L-shaped section 12 instead of the section 11 by means of which the strip 21 is secured to a side wall 10 of the housing 1. Wiring 13 can be carried in the housing above the section 12.
A still further modification is shown in Fig. 22 in which the lower region 6, the intermediate region 5 and the upper region 4 are provided, respectively, on separate strips 22, 23 and 24. The upper strip 24 has a section 11 for securing it to the surface 3 of the housing 1 and the intermediate strip 23 has an L-shaped section 25 for securing it to the side wall 10 of the housing. Again, wiring 13 may be carried in the housing above the section 25.
The modification shown in Fig. 23 is similar to that shown in Fig. 22 except that in this case, the upper strip 24 is provided with an L-shaped section 12 instead of the section 11 and further wiring 26 can be carried in the housing above this section.
The luminaires shown in Figs. 24 to 27 differ from the previous examples in that, in this case, the housing 1 is provided with inclined walls 27, the inner surface of which constitutes the upper reflective region 4. In Fig. 24, the intermediate region 5 and lower region 6 are provided on a strip 28 which has an L-shaped section 9 by means of which it is secured to a side wall 10 of the housing. In Fig. 25, the intermediate region 5 is provided on a separate strip 29 which is secured to the strip 28. This embodiment is otherwise similar in every respect to the embodiment shown in Fig. 24.
In the embodiment shown in Fig. 26, the intermediate region 5 is also provided on the inner surface of the inclined walls 27 and a separate strip 22 on which the lower region 6 is provided is secured to a side wall 10 of the housing 1 as in the embodiments shown in Figs. 20 to 23. The embodiment shown in Fig. 27 is similar to the embodiment shown in Fig. 26 except that in this case the intermediate region 5 is provided on a separate strip 30 which is secured to the lower portion of the inclined side wall 26.
It will now be found that a luminaire fitted with any one of the above-described reflectors according to the invention will provide soft lighting and even distribution without glare and will have a pleasing appearance when viewed from all distances and angles.
The invention is not restricted to the above-described embodiments but variation and modification may be made without departing from the scope of the claims. For example, a reflector may be provided with a transverse cut-off of 45° to the light tube in order to satisfy the cut-off recommendations of the CIBSE memorandum TM6 which may be needed in large open plan spaces with a large number of VDU's. Further, the upper regions and intermediate zones of the reflector strips need not be painted but may be provided with any suitable coating provided that it is highly reflective. Moreover, in the embodiments shown in Fig. 1 to 11 of the drawings, a strip of plastics material may be applied to a substantially planar reflector strip to achieve the shallower-angled intermediate region. The intermediate region of these embodiments may also be provided with a graduated colouring effect as in one or more of the embodiments shown in Figs. 12 to 17 of the drawings if desired.

Claims

A luminaire with a reflector system which is designed to reflect light from a light tube and which extends substantially the length of the light tube, the reflector system comprising two reflector parts at both sides of the tube and each part comprising a first reflective upper region beside the tube and a second reflective lower region having lower luminance than the upper region, wherein the said upper and lower regions are interconnected by an intermediate region having a reflecting surface which has an effective luminance between the luminance of the said upper and lower regions.
A luminaire according to claim 1, wherein the upper region of each reflector part is located above and to one side of the light tube.
A luminaire according to claim 1 or claim 2, wherein it comprises a housing containing the light tube and two strips arranged to be located on either side of the light tube, the strips extending substantially the length of the light tube and each strip comprising an upper region and a lower region interconnected by an intermediate region having intermediate luminance.
A luminaire according to claim 1 or claim 2, wherein it comprises a housing containing the light tube and wherein at least the said upper region constitutes part of said housing, the lower region being provided on two strips arranged in the housing and extending substantially the length of the light tube, each strip being connected to the housing and spaced from the upper region by said intermediate region having intermediate luminance.
A luminaire according to claim 3, wherein the upper region, intermediate region and lower region of each strip are provided on a single integral component.
A luminaire according to claim 3 or claim 4, wherein the upper region and intermediate region are formed as an integral component and the lower region is formed on a separate strip.
A luminaire according to claim 3 or claim 4, wherein the lower region and intermediate region are formed on a single strip as an integral component which is secured to the housing.
A luminaire according to claim 3 or claim 4, wherein the upper region, intermediate region and lower region are formed as separate components each connected to the housing.
A luminaire according to any preceding claim, wherein the said upper and lower regions are interconnected by an intermediate region having a reflecting surface which extends outwardly from the first upper region at a shallower angle so that its effective luminance is between the luminance of the said upper and lower regions.
A luminaire according to claim 9, wherein the upper region is inclined at an angle of between 40° and 45° to the vertical, the lower region extends at a narrower angle to the vertical than the upper region, preferably less than 20°, and the intermediate region extends at a wider angle to the vertical than the upper region, preferably about 65°.
A luminaire according to claim 5, wherein the strip on which the upper, lower and intermediate regions are provided is arcuate.
A luminaire according to any one of claims 5 to 11, wherein the strips are interconected, at intervals, by crossblades, which are preferably wedge-shaped.
A luminaire according to any preceding claim, wherein the upper region is white.
A luminaire according to any preceding claim, wherein the lower region is made of aluminium or an aluminium alloy which is uncoloured.
A luminaire according to claim 9 or claim 10, wherein the intermediate zone is coloured white.
A luminaire according to any preceding claim, wherein the intermediate zone is partially coloured white, the white colouring taking the form of spots or lines or a zig-zag formation.
A luminaire according to claim 16, wherein the white colouring of the intermediate zone comprises spots or lines which increase in size and/or number from the lower region towards the upper region.
A luminaire according to any one of claims 1 to 14, wherein the intermediate zone is coloured grey, the grey colouring preferably getting progressively darker from the upper region to the lower region.