A LIGHTING ARMATURE

Abstract: The invention relates to a lighting armature provided with a light source (2), which is disposed within a reflector (1) having an elongated shape. Two boundary edges (8) of the reflector bound an elongated opening, whereby an elongated element (9) of light-transmitting material, which closes the greater part of said opening, is disposed near said opening. A boundary surface of the elongated element (9) that faces the light source (2) extends substantially between the boundary edges (8) of the opening. Further boundary surfaces (11, 12) extending in a direction away from the light source (8) and towards each other join the longitudinal edges of the boundary surface (10) facing the light source (2) of the element of light-transmitting material.

Description: A 1 ighting armature. The invention relates to a lighting armature provided with a light source, which is disposed within a reflector having an elongated shape, of which two boundary edges bound an elongated opening, whereby an elongated element of light-transmitting material, which closes the greater part of said opening, is disposed near said opening, and whereby a boundary surface of said elongated element that faces said light source extends substantially between said boundary edges of said opening. Lighting armatures of this kind, which accommodate one or more light sources, usually in the form of TL-tubes, and which may be provided with a thin glass plate disposed at the level of the opening bounded by the boundary edges of the reflector, are generally known. In many cases such lighting armatures are fitted in ceilings, whereby said opening is usually located at the same level as the underside of the ceiling. With these known lighting armatures the surface area lighted by the light source is to a large degree determined by the width of the opening bounded by the edges of the reflector and the interior height of the reflector or by the width and height of a box accommodating the light source. All this frequently has an adverse effect on the evenness of the lighting in a particular room. The object of the invention is to obtain a lighting armature of the above kind, which makes it possible to achieve a satisfactory, even lighting. According to the invention this objective can be accomplished in that further boundary surfaces extending in a direction away from the light source and towards each other join the longitudinal edges of the boundary surface facing the light source of the element of light-transmitting material. By using a lighting armature according to the invention substantially the greater part of the light emitted by the light source(s) will travel through the interior of the element via the boundary surface facing the light source of the element of light-transmitting material, whereby the light beams are refracted in the interior of the element and the light is emitted towards the outside by said further boundary surfaces of said element of light-transmitting material, which project under said reflector. In practice it has become apparent that in this manner a very even lighting can be achieved, whilst the occurrence of objectionable luminance appears to have been greatly reduced in comparison with known constructions. Another advantage is the fact that the light source(s) are fully hidden from view by the reflecting surfaces of the element of light-transmitting material, so that the light source or light sources do not stand out in an objectionable manner and an aesthetically attractive appearance of the light-emitting element is obtained. Furthermore it is possible to effect a desired refraction of the light in the longitudinal and transverse directions of the armature with the element of light-transmitting material, so that it will not be necessary to use cross lamellae in the armature. It is noted that from DE-U-8515067 (Figure 2) a 1 ighting armature is known wherein a light-guiding element extending in the longitudinal direction of the reflector and having a trapezoidal section is disposed under the reflector. The width of this element is considerably less than the width of the opening between the boundary edges of the reflector. The purpose of using this element is that the upwardly sloping lateral boundary surfaces of the element, which extend towards each other, reflect the light from the light source in the direction of the ceiling. From EP-A-0369338 a lighting armature is furthermore known wherein an optical element having light-refracting properties is provided in the interior of the reflector and above cross lamellae present in the reflector. Said optical element functions to refract the light beams falling onto the optical element and to deflect at least part of said light beams in the direction of parts of the reflector positioned below said optical element, from where the light is subsequently beamed into the room. These known constructions are different from the construction according to the invention, therefore, and in this known construction a large part of the light emitted by the light source finds its way into the room by travelling along the elements of light- transmitting material, this in contrast to the construction according to the invention. A particularly optimal util ization of the 1 ight emitted by the light source can be achieved when an elongated element having a V-shaped section, of which at least the side facing the light source is reflective, is disposed between the light source and the upper part of the reflector, in such a manner that the part of the elongated element extending in the longitudinal direction of the reflector that is located furthest away from the elongated opening of the reflector is made up of the top of said element, which top is positioned in the longitudinal central plane of the reflector, whilst slots are provided in wall parts of the elongated element extending from the top of said elongated element in a direction away from each other, whereby the slots provided in one wall part are staggered with respect to the slots provided in the other wall part, seen in the longitudinal direction of the elongated element. When this embodiment of the construction according to the invention is used, light emitted in upward direction from the light source will fall on the wall parts of the elongated element having a V- shaped section, whereby light falling onto one wall part will be reflected in the direction of the reflector through the slots in the other wall part, and from there in the direction of the elongated element of light- transmitting material again. In practice it has become apparent that in this manner a particularly favourable utilization of the light emitted by the light source can be realized, whilst achieving an even lighting of the room to be lighted. It is noted that the term V-shaped should be given a broad interpretation, it is also meant to include constructions having a curved or a more or less U-shaped section. The invention will be explained in more detail hereafter with reference to embodiments of the construction according to the invention, which are diagrammatically illustrated in the accompanying Figures. Figure 1 is a diagrammatic, cross-sectional view of a part of a lighting armature according to the invention. Figure 2 shows several other possible embodiments of elements consisting of light-transmitting material in cross-sectional view. Figure 3 is a diagrammatic, perspective view of one end of another embodiment of a lighting armature according to the invention. Figure 4 is a cross-sectional view of the lighting armature of Figure 3. Figure 5 is a perspective view of a part of an elongated element having a V-shaped section. Figure 1 is a cross-sectional view of a part of a lighting armature provided with a reflector 1, which extends in the longitudinal direction of the armature, perpendicularly to the plane of the drawing, and which surrounds part of the circumference of a light source 2, usually a TL-tube. In the illustrated embodiment reflector 1 comprises a curved central part 3, which blends near its boundary edges into connecting parts 4 extending in a direction away from the light source, which connect central part 3 of the reflector to further curved reflector parts 5. At their ends facing away from connecting parts 4 said reflector parts 5 blend into connecting parts 6 likewise extending in a direction away from the light source 2, which connect reflector parts 5 to further curved reflector parts 7. The lower boundary edges 8 of said reflector parts 7 bound an opening, near which an element 9, which may or may not be concave, of light-transmitting material is disposed. In the embodiment shown in Figure 1 the elongated element extending perpendicularly to the plane of the drawing has a triangular section and comprises a boundary surface 10 facing the light source, which lies at least substantially in one plane with the boundary edges 8 of reflector 1, and two boundary surfaces 11 and 12 extending in a direction away from the light source and towards each other, all this in such a manner that element 9 has a triangular cross-section. As is indicated by light beams A, a large part of the light emitted by the light source 2 will fall onto the interior of reflector 3 and be reflected from there to the boundary surface 10 of element 9 facing the light source. Part of the emitted light, indicated by light beam B, will fall directly onto said surface 10. The light falling onto boundary surface 10 of the element facing the light source will travel through the element 9 consisting of light-transmitting material, for example glass or plastic material, whereby the light beams will be refracted near the boundary surfaces upon entering and exiting the element. Preferably the reflector 1 is selected to have a configuration such that at least the greater part of the light falling onto the part of the reflector that is located on one side of the plane of symmetry S-S of the armature will fall onto a part of surface 10 that is located on the other side of said plane of symmetry S-S. During use the element 9 projecting under said reflector has the appearance of an element emitting evenly shining light, which, as has become apparent in practice, will result in a very even lighting of a comparatively large area with hardly any objectionable luminance, which is in particular important when lighting rooms in which people frequently work with display screens. The angle at which the light is emitted is determined by the light refraction effects of the light-transmitting element, and consequently is no longer dependent on the height and width of the armature, more in particular of the reflector. This makes it possible to use armatures having a small width and height, so that said armatures do not require a great deal of fitting space, whilst an efficient and satisfactory lighting of the room to be lighted can still be effected by means of elongated element 9, whereby it is possible in many cases to space the armatures further apart than has been usual so far, partly due to the smaller-width construction of the armature. Furthermore it is no longer necessary for the reflector to be provided with cross lamellae. In principle the boundary surface 10 may extend to near the boundary edges 8 of the reflector. In the illustrated embodiment, however, slots 13 extending in the longitudinal direction of the armature are present between the ends of boundary surface 10 of element 9 and the boundary edges 8 of the reflector, in which slots decorative elements of a desired colour, which may or may not transmit light, may be disposed. The manner of light diffusion by means of elongated element 9 can be influenced not only by varying the top angle between the two boundary surfaces 11 and 12 and/or the refraction index of the material used for forming said element, but also by varying the configuration of the various boundary surfaces; several possible configuratons are shown in Figure 2. In Figure 2a the boundary surface 10 facing the light source is slightly curved, whereby the centre of curvature of said curved surface is located on the side of surface 10 that faces away from the light source. Figure 2b likewise shows a curved configuration of the boundary surface 10 facing the light source, in this embodiment the centre of curvature of said curved boundary surface is located on the same side of boundary surface 10 as the light source. In the embodiment shown in Figure 2c the boundary surface facing the light source is built up of two curved portions 10a and 10b, which are positioned symmetrically with respect to the plane through the intersection of boundary surfaces 11 and 12, which divides element 9 in two. The centres of curvature of said curved portions are thereby located on the side of element 9 that faces the light source. Figure 2d shows an embodiment wherein the surface facing the light source is likewise built up of two curved portions 10a' and 10b ' , whose centres of curvature are located on the side of said boundary surface that faces away from the light source, however. Figure 2e shows an embodiment corresponding with Figure 2d, wherein the boundary surfaces 10a ' and 10b ' exhibit a more pronounced curvature. Figures 2f-2i show various embodiments, wherein the boundary surface 10 facing the light source is toothed to a smaller or larger degree, in order to effect a stronger diffusion of the light beams in the interior of element 9. Figure 2j shows an embodiment wherein the boundary surface 10 facing the light source has a configuration similar to that of the embodiment shown in Figure 2b. The two boundary surfaces 11 and 12 are likewise curved and blend evenly together. It will be apparent that further embodiments of the element of light-transmitting material are conceivable, which embodiments may be formed by combinations of the various embodiments shown in Figure 2. Although the above description relates to armatures to be fitted in a ceiling, it will be apparent that such an armature may also be used in different manners, for example as suspended lamps or as elongated "spotlights" for illuminating objects. Also the configuration of the reflector may be different from the embodiment that has been illustrated and described, partly depending on the light situation. The lighting armature shown in Figures 3 and 4 largely corresponds with the lighting armature shown in Figure 1. Parts that correspond with each other are indicated by the same numerals, therefore, and will not be discussed anew. As is shown in Figures 3 and 4, said further embodiment comprises an elongated element 14 disposed between the upper side of light source 2 and the curved central portion 3 of reflector 1, which element extends in the longitudinal direction of reflector 1. Elongated element 14 has a U-shaped or a V-shaped section and is thereby disposed in such a manner that the top of said section lies in the longitudinal central plane S-S of reflector 1, whilst the two wall parts 15 and 16 of elongated element 14 extending in a direction away from each other extend from the top towards the light source and towards element 9 respectively. At least the side of elongated element 14 that faces light source 2 will be made of reflective material; preferably both sides will be reflective, however. As will be apparent in particular from Figure 3, elongated slots 17 and 18 are furthermore provided in wall parts 15 and 16 respectively, in such a manner that said slots extend perpendicularly to the longitudinal direction of the elongated element. The construction is thereby such that, seen in the longitudinal direction of elongated element 14, the slots 17 provided in wall part 15 are staggered with respect to slots 18 formed in wall part 16 of elongated element 14. A large part of the light emitted by light source 2 will fall onto the interior of reflector 1, as is indicated by light beam A, and be reflected from there to the boundary surface 10 of element 9 that faces the light source. Furthermore another part of the emitted light, indicated by light beam B, will fall directly onto said plane 10. Yet another part of the light will finally fall onto wall parts 15 and 16 of elongated element 14. For example, light falling onto wall part 15, as indicated by light beam C in Figure 2, will be reflected by slots 18 formed in wall part 16 of elongated element 14 and will subsequently fall onto reflector 1 again and be reflected from there onto the upper surface 10 of element 9. In a similar manner light falling onto wall part 16 through the slots in wall part 15 (arrow D in Figure 3) will be reflected onto the interior of reflector 1, and from there onto upper surface 10 of element 9. By using elongated element 14 at least a large part of the light emitted from light source 2 in the direction of the central portion 3 of reflector 1 is received and reflected in such a manner that a very favourable utilization of the light emitted by the light source will be achieved. Light beams entering element 14 through slots 17 and 18 can be reflected, at least partially so, in the direction of the slots 13 positioned beside surface 10 of element 9, and illuminate decorative elements that may be present at that location, as is indicated by light beam E. Although the combination of the reflector 1 as described and illustrated with elongated element 14 is particularly efficient, it will be conceivable to use elongated element also in combination with reflectors having different sectional configurations. Furthermore it will be apparent that the lighting armature can be used not only for interior lighting but also for exterior 1 ighting.

Claims: CLAIMS 1. A 1 ighting armature provided with a light source, which is disposed within a reflector having an elongated shape, of which two boundary edges bound an elongated opening, whereby an elongated element of light-transmitting material, which closes the greater part of said opening, is disposed near said opening, and whereby a boundary surface of said elongated element that faces said light source extends substantially between said boundary edges of said opening, characterized in that further boundary surfaces extending in a direction away from the light source and towards each other join the longitudinal edges of the boundary surface facing the light source of the element of light- transmitting material. 2. A 1 ighting armature according to cl aim 1 , characterized in that an elongated element having a V-shaped section, of which at least the side facing the light source is reflective, is disposed between the light source and the upper part of the reflector, in such a manner that the part of the elongated element extending in the longitudinal direction of the reflector that is located furthest away from the elongated opening of the reflector is made up of the top of said element, which top is positioned in the longitudinal central plane of the reflector, whilst slots are provided in wall parts of the elongated element extending from the top of said elongated element in a direction away from each other, whereby the slots provided in one wall part are staggered with respect to the slots provided in the other wall part, seen in the longitudinal direction of the elongated element. 3. A lighting armature according to claim 1 or 2, characterized in that the reflector is configured such that, seen in the longitudinal direction of the reflector, light falling onto the reflector on one side of a plane of symmetry of the armature that extends through said reflector and said element is reflected to a boundary surface of the element of light-transmitting material that faces the light source, which boundary surface is located on the other side of said plane of symmetry. 4. A lighting armature according to any one of the preceding claims, characterized in that said element of light-transmitting material has a substantially triangular cross-section. 5. A lighting armature according to any one of the preceding claims, characterized in that the boundary surface of said element that faces the light source has a slightly curved configuration, when seen in sectional view. 6. A lighting armature according to any one of the preceding claims 1 - 4, characterized in that, seen in sectional view, the boundary surface of said element of light-transmitting material that faces the light source is built up of two parts having a curved configuration. 7. A lighting armature according to claim 5 or 6, characterized in that the centre of curvature of a part having a curved configuration of the boundary surface facing the light source is located on the same side of the boundary surface facing the light source as said light source. 8. A lighting armature according to claim 5 or 6, characterized in that the centre of curvature of a part having a curved configuration of the boundary surface facing the light source is located on the side of the boundary surface facing the light source that faces away from said light source. 9. A lighting armature according to any one of the preceding claims 1 - 4, characterized in that the boundary surface of said element of light-transmitting material that faces the light source is toothed when seen in sectional view. 10. A lighting armature according to any one of the preceding claims, characterized in that the boundary surfaces which extend from the boundary surface of the element that faces said light source in a direction away from the light source have a rectilinear configuration, when seen in sectional view. 11. A lighting armature according to any one of the preceding claims 1 - 9, characterized in that the boundary surfaces which extend from the boundary surface of the element that faces said light source in a direction away from the light source have a curved configuration and blend evenly into each other. 12. A lighting armature according to any one of the preceding claims, characterized in that, seen in sectional view, the reflector is built up of a few curved parts, which are provided near their ends with connecting parts extending transversely to said curved parts. 13. A lighting armature according to any one of the preceding claims, characterized in that the reflector is provided in its longitudinal central plane, on the side of the elongated element that faces away from the light source, with a part having an angular section and being symmetric with respect to said longitudinal central plane. 14. A lighting armature according to any one of the preceding claims, characterized in that said element of light-transmitting material is concave.

Inventors: VAN PUTTEN SIMON CORNELIS, VAN PUTTEN, SIMON, CORNELIS
Applicants: PUTTEN SIMON CORNELIS VAN, VAN PUTTEN, SIMON, CORNELIS
Application year: 1997
Main classification: F21V11
IPC codes: F21S8, F21V8, F21V11, F21V13