EP1350061A2 - Luminaire comprenant une source lumineuse allongee et un retroreflecteur - Google Patents

Luminaire comprenant une source lumineuse allongee et un retroreflecteur

Info

Publication number
EP1350061A2
EP1350061A2 EP01987284A EP01987284A EP1350061A2 EP 1350061 A2 EP1350061 A2 EP 1350061A2 EP 01987284 A EP01987284 A EP 01987284A EP 01987284 A EP01987284 A EP 01987284A EP 1350061 A2 EP1350061 A2 EP 1350061A2
Authority
EP
European Patent Office
Prior art keywords
luminaire
reflector
light
light source
cavity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01987284A
Other languages
German (de)
English (en)
Inventor
Michael C. Lea
John C. Wright
Andrew M. Hicks
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Innovative Properties Co
Original Assignee
3M Innovative Properties Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 3M Innovative Properties Co filed Critical 3M Innovative Properties Co
Publication of EP1350061A2 publication Critical patent/EP1350061A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—Reflecting element, sheet or layer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V13/00—Producing particular characteristics or distribution of the light emitted by means of a combination of elements specified in two or more of main groups F21V1/00 - F21V11/00
    • F21V13/02—Combinations of only two kinds of elements
    • F21V13/04—Combinations of only two kinds of elements the elements being reflectors and refractors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
    • F21V17/04—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages the fastening being onto or by the light source
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V19/00—Fastening of light sources or lamp holders
    • F21V19/0075—Fastening of light sources or lamp holders of tubular light sources, e.g. ring-shaped fluorescent light sources
    • F21V19/008—Fastening of light sources or lamp holders of tubular light sources, e.g. ring-shaped fluorescent light sources of straight tubular light sources, e.g. straight fluorescent tubes, soffit lamps
    • F21V19/009—Fastening of light sources or lamp holders of tubular light sources, e.g. ring-shaped fluorescent light sources of straight tubular light sources, e.g. straight fluorescent tubes, soffit lamps the support means engaging the vessel of the source
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/005—Reflectors for light sources with an elongated shape to cooperate with linear light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/22—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
    • F21V7/24—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors characterised by the material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/22—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
    • F21V7/28—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors characterised by coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2103/00—Elongate light sources, e.g. fluorescent tubes

Definitions

  • the present invention relates to luminaires of the type comprising an elongate light source and a back reflector.
  • the invention is especially, but not exclusively, applicable to luminaires employing fluorescent tubes as light sources.
  • Elongate light sources in the form of fluorescent tubes are widely used in luminaires for space lighting, both indoors and outdoors. They also have many other uses, for example in shelf lighting and in display lighting, including not only commercial and emergency signs but also electronic displays.
  • the distribution of light required from a luminaire depends on the use for which the luminaire is intended. For example, in the case of ceiling-mounted luminaires employing fluorescent tubes for general space lighting, a light output having a wide angle transverse distribution of the so-called "batwing” type is often preferred because that enables a relatively uniform level of illumination at floor level to be achieved even when the luminaires are comparatively widely spaced. If the space to be illuminated is one in which computer display screens are used, the "batwing" distribution preferably exhibits a cut-off at about 60° on either side of the downward vertical to reduce the amount of glare from the display screens experienced by the users.
  • the light output of the luminaire should have a narrow transverse distribution so that as much light as possible is injected into the guide.
  • a fluorescent tube will normally emit light generally uniformly in all directions around its axis and, in a luminaire, it is often provided with a back reflector for re-directing rearwardly-emitted light in a forwards direction.
  • Spaced back reflectors are widely used with fluorescent tubes for space lighting, and are also frequently used with fluorescent tubes in backlights for electronic displays, and they can result in luminaires that are very efficient in their use of energy.
  • the back reflectors are, however, often very bulky in comparison with the light sources, and not always suitable for use in confined spaces.
  • front diffusers are often also required to provide a uniform level of illumination at floor level and add further to the bulkiness of the construction.
  • Examples of luminaires comprising a linear light source provided with a spaced back reflector are described in US-A-4 642 741, US-A-4 514 793 and US-A-3 654 471.
  • the back reflector can be wrapped around the linear light source for shipment and handling.
  • aperture lamps As an alternative to luminaires comprising fluorescent tubes with spaced back reflectors, so-called “aperture lamps” have been developed.
  • a reflective material closely surrounds (or is integral with) part of the circumference of the fluorescent tube leaving an elongate aperture through which the light (including light reflected by the reflective material) can emerge.
  • the reflective material can be a sheet material or a coating applied directly to the inside or the outside of the fluorescent tube, oiapplied to the inside or outside of a protective sheath that completely surrounds the tube.
  • the aperture can exhibit high levels of surface luminance but does not always provide a controlled light distribution.
  • back reflectors have been used that engage closely around a lighting tube.
  • a lighting tube with a spaced back reflector requires more space, it will generally be more energy-efficient than a comparable aperture lamp, because light will undergo fewer reflections before being emitted in the forwards direction so that the amount of light lost on reflection is reduced.
  • US-A-4 933 821 and US-A-5 414 604 describe luminaires comprising spaced back reflectors that are shaped to ensure that some of the light from a fluorescent tube leaves the luminaire at a sharp angle to the remainder of the light.
  • the luminaire described in US-A-4 933 021 that is achieved by shaping the edge of the reflector.
  • US-A-4 418 378 the output of a fluorescent tube used in a light box is modified by providing the tube with an apertured sleeve with cut-away ends.
  • the problem with which the present invention is concerned is that of providing, for an elongate light source in a luminaire, a reflector that is comparatively compact and will not only re-direct light in a required direction but will also enable the distribution of the light from a luminaire to be tailored to meet the requirements of particular situations in which the luminaire is to be used.
  • the present invention provides a luminaire comprising a reflector that defines an elongate concave cavity in which an elongate light source is located in spaced relationship to the reflector whereby the latter surrounds the light source on its rearward side to reflect light from the source and cause it to be emitted from the cavity in a generally-forwards direction; the reflector being provided with a prismatic structure upstanding from its imier surface to intercept and deviate light that is emitted, in the generally-forwards direction, from the space in the cavity between the light source and the reflector.
  • the present invention also provides a luminaire comprising a reflector that defines an elongate concave cavity in which an elongate light source is located in spaced relationship to the reflector whereby the latter surrounds the light source on its rearward side to reflect light from the source and cause it to be emitted from the cavity in a generally-forwards direction; the reflector being provided, on opposite sides of the cavity, with a respective prismatic structure upstanding from its inner surface to intercept and deviate light that is emitted, in the generally-forwards direction, from the space in the cavity between the light source and the reflector.
  • the elongate light source of a luminaire in accordance with the invention should be one that will not completely absorb light that is returned to it by the reflector and will preferably absorb substantially none of that light.
  • a suitable light source is a fluorescent tube.
  • light refers to electromagnetic radiation in the ultraviolet, visible and/or infrared regions of the electromagnetic spectrum.
  • prismatic structure normally refers to a structure whose two ends are similar, equal and parallel rectilinear figures, and whose sides are parallelograms.
  • a prismatic structure has a triangular cross-section.
  • the term extends to structures having cross-sections with more than three sides and also to the limiting case in which the structure has a cross-section with a multiplicity of sides to the extent that at least some of those sides form a curve.
  • Fig. 1 is an exploded perspective view of a luminaire in accordance with the present invention
  • Fig. 2 is a perspective view of the luminaire of Fig.1, in an assembled condition
  • Fig. 3 shows a transverse cross-section through the luminaire of Fig. 2;
  • Fig. 3 A illustrates the output light distribution of the luminaire in the plane of Fig. 3;
  • Figs. 4, 5, 6 and 7 show transverse cross-sections through respective luminaires in accordance with the invention;
  • Figs. 4A, 5 A and 6A illustrate the output light distributions of the luminaires of Figs. 4, 5 and 6 respectively in the planes of those Figures;
  • Fig. 8 is a diagrammatic illustration of a backlighting system incorporating a luminaire in accordance with the invention.
  • the luminaire shown in an exploded condition in Fig. 1 and in an assembled condition in Fig. 2, comprises a linear fluorescent tube and a reflector 3.
  • the reflector 3 is of elongate form and, as shown in Fig. 3, has a generally-concave transverse cross-section that defines a cavity 4 in which the light source 2 is located so that it is partially surrounded, on one side, by the reflector.
  • the reflector 3 forms the rear of the luminaire which, in use, is intended to emit light in a forwards direction, out of the cavity 4 (that is, away from the reflector).
  • the reflector 3 comprises an elongate shell 5 with a transverse cross-section that is approximately semi-circular, and three upstanding longitudinally-extending ribs 6, 7 on its inner surface. Two of the upstanding ribs, indicated by the reference 6, are located at the longitudinal edges of the shell 5, and the third upstanding rib 7 is located at the centre.
  • the reflector 3, comprising the shell 5 and the ribs 6, 7, is formed from an optically- transparent (preferably polymeric) material and is preferably a moulded or extruded component.
  • a suitable material for the reflector 3 is polycarbonate but it could, alternatively, be formed from an acrylic material.
  • the ribs 6, 7 contact the envelope of the fluorescent tube 2 and serve to space the shell 5 from the latter and, in the case of the ribs 6, to modify the distribution of the light leaving the luminaire 1 as will be described in greater detail later.
  • a highly-efficient specularly-reflecting layer 8 is formed on the outer surface of the shell 5 (including, as shown, the edge portions opposite the bases of the ribs
  • the reflector 3 may be mounted on, or form a part of, a fitting for receiving the fluorescent tube 2. Alternatively, it may be mounted directly on the envelope of the tube 2, in a manner that permits it to be removed and, possibly, adjusted relative to the tube as required. In a preferred arrangement, the reflector 3 extends around the fluorescent tube 2 to an extent that enables it to be retained on the tube solely by the action of the ribs 6, it being necessary only to provide some means for securing the reflector relative to the tube in the desired circumferential location. In that case, the shell 5 of the reflector 3 must be sufficiently flexible to permit insertion and removal of the tube 2 when required.
  • the luminaire 1 functions generally as follows.
  • the fluorescent tube 2 will emit light generally uniformly in all directions around its longitudinal axis.
  • Light that is emitted in the rearwards direction, i.e. towards the reflector 3, will pass through the shell 5 and be reflected by the layer 8 back towards the fluorescent tube 2, where it may be reflected again and returned to the layer 8.
  • Light may, in fact, undergo multiple reflections in the cavity 4, in the space between the fluorescent tube 2 and the shell 5, before it is finally able to leave the cavity 4 (travelling in the forwards direction) through either the tube 2 or one of the ribs 6.
  • the reflector 3 functions in a conventional manner.
  • the layer 8 should have a reflectivity of at least 90%, preferably at least 98%, facing into the cavity 4.
  • the layer 8 may comprise a reflective film that is laminated to the outer surface of the shell 5, in which case a preferred reflective film is a multi-layer optical film of the type described in US-A-5 882 774 and WO 97/01774.
  • a suitable alternative film is available, under the trade designation "Miro", from Alanod of Ennepetal, Germany.
  • the layer 8 could be a vapour-deposited layer.
  • the layer 8 may be primarily a diffusely-reflecting material although strips of specularly- reflecting material would be required opposite the bases of the ribs 6.
  • the reflective layer 8 is transferred to the inner surface of the shell 5, although strips of specularly-reflective material are retained on the outer surface opposite the bases of the ribs 6.
  • Each of the ribs 6 is in the form of a prism having a triangular cross-section, the base of the prism being a continuation of the outer surface of the shell 5 of the reflector 3 and the apex of the prism being adjacent the envelope of the fluorescent tube 2.
  • the two prisms 6 have identical cross-sections in the form of an isosceles triangle and are positioned and oriented symmetrically relative to the tube 2. Light that passes through one of the prisms 6 as it leaves the cavity 4 will be deviated by the prism and, through an appropriate orientation of the prism and selection of the prism angle, it is possible to control the direction in which that light will leave the luminaire. It is further possible to adjust the amount of light that passes through the prisms 6 by altering the extent to which the reflector 3 wraps around the fluorescent tube 2.
  • the extent of the reflector 3 (measured as the distance between the apexes of the prisms 6) is such that the reflector wraps around 55% of the circumference of the tube 2.
  • the prisms 6 have a prism angle ⁇ of 76°and each is oriented so that the outer face of the prism is at an angle ⁇ of 68° to the plane containing the prism apexes with the result that the prism apexes are directed into the cavity 4.
  • Fig 3 A illustrates the effect of the reflector 3 on the angular distribution of light from a luminaire of this construction, in the plane of Fig. 3 (i.e. transverse to the length of the tube 2).
  • Fig 3 A shows that, in this plane, the light has an intensity peak in the forwards direction (0° in Fig. 3 A) and declines to zero on each side of the forwards direction more rapidly than would the light from a Lambertian source.
  • the light In the orthogonal plane (i.e. along the length of the tube 2), the light also has an intensity peak in the forwards direction but the effect of the reflector 3 is less apparent.
  • Fig. 4 is similar to Fig. 3 and illustrates a luminaire in which the prisms 6 are oriented so that the outer face of each prism is at an angle ⁇ of 8° to the plane containing the prism apexes, with the result that the apex of each prism is directed out of the cavity 4.
  • Fig 4 A is similar to Fig. 3 A and illustrates the effect of the reflector 3 on the angular distribution, in the plane of Fig. 4, of the light from a luminaire of this construction. It will be seen that, in this plane, the light again has an intensity peak in the forwards direction (0° in Fig. 4).
  • the light In the orthogonal plane (i.e. along the length of the tube 2), the light also has an intensity peak in the forwards direction but the effect of the reflector 3 is less apparent.
  • Luminaires of the type shown in Figs. 3 and 4 which provide a beam of light with an intensity peak in the forwards direction, are particularly suitable for edge illumination of light guides because they will enable a comparatively high level of light to be injected into the guide thereby enabling the efficiency of the system to be increased.
  • the light guides can have various uses, for example, as electronic displays or edge-lit signs or may, themselves, also function as luminaires.
  • Luminaires of the type shown in Figs. 3 and 4 are also suitable for use in "wall-washing" lighting systems for illuminating surfaces (e.g. sign faces) and for illuminating merchandise in retail locations.
  • they are particularly suitable for installation above the aisles between storage racks in warehouses to illuminate the racks effectively without hindering the mobility of forklift trucks.
  • Fig. 5 is a similar view to those of Figs. 3 and 4 but illustrates a luminaire that will provide a completely different light distribution. In this case, the extent of the reflector 3
  • Fig 5A illustrates the effect of the reflector 3 on the angular distribution, in the plane of Fig. 5, of the light from a luminaire of this construction.
  • the distribution has a so-called "batwing” form, in which the light intensity has two peaks, one on each side of the forwards direction (in this case, at an angle of about 40°) and then declines to zero following a Lambertian distribution as the angle widens.
  • the orthogonal plane i.e. along the length of the tube 2
  • the effect of the reflector 3 on the angular distribution of the light is less apparent.
  • Fig. 6 illustrates a modification of the construction shown in Fig. 5.
  • the principal modification comprises continuing the reflector 3 beyond the prisms 6 to form similar outwardly-inclined extensions 9 along each edge of the curved shell 5 of the reflector.
  • a highly-efficient specularly-reflecting layer 10, similar to the layer 8, is formed on the outer surface of each extension 9.
  • the extensions 9 function to intercept light that would otherwise leave the luminaire 1 at a comparatively wide angle (including, in each case, some light from the prism 6 on the other side of the reflector), and cause it to be emitted in a more forwards direction.
  • Fig 6 A illustrates the angular distribution, in the plane of Fig.
  • Luminaires of the type shown in Figs. 5, providing a wide-angle "batwing” distribution are particularly suitable for general space lighting applications. It is already known, when a plurality of ceiling-mounted luminaires is used to illuminate a floor space, that luminaires providing a "batwing” distribution are most efficient in that they can be spaced more widely apart without compromising the uniformity of the illumination provided. Luminaires of the type shown in Fig. 6 are preferred for lighting spaces, such as offices, in which computer display screens are used. In that case, because the light emitted by each luminaire is contained within an angle of about 60° around the downward vertical, the glare from the display screens will be much less troublesome to the users. It will be appreciated that, for ceiling mounting, the luminaires of Figs. 5 A and 6A would be oriented so that the emitted light is directed downwards towards the floor area of the space to be illuminated.
  • the orientation of the prisms 6 can all be altered to modify the distribution of the emitted light.
  • the orientation of the prisms 6 has the greatest effect on the light distribution.
  • Increasing the extent of the reflector 3 (measured between the apexes of the prisms 6), and hence the degree to which the light source 2 is surrounded, will reduce the efficiency of the luminaire since less light will be emitted but will also reduce the amount of light that is emitted in an uncontrolled manner.
  • a luminaire with a "batwing" light distribution as in Figs.
  • the reflector 3 (measured between the apexes of the prisms 6) preferably surrounds about 75% of the circumference of the light source 2 although anything between 55% and 85% is satisfactory.
  • a smaller proportion of the light source 2 would normally be surrounded by the reflector 3.
  • consideration may need to be given to the mechanism used for maintaining the position of the reflector relative to the light source.
  • One preferred construction for providing a batwing light distribution which is of the type shown in Fig.
  • the sixth uses a fluorescent tube 2 having a diameter of 25mm and the distance between the apexes of the two prisms 6 of the reflector 3 is sufficient to surround about 75% of the circumference of the tube.
  • the length of the prism sides, between the base and the apex, is 10mm; the prism apex angle ⁇ is 74°; and the prisms are oriented so that the outer face of each prism is at an angle ⁇ of 40° to the plane containing the prism apexes.
  • the extensions 9 have a width of 20mm and are inclined outwards at an angle of 100° to the plane containing the apexes of the prisms 6.
  • the reflectors 3 of the luminaires of Figs. 3 to 6 have a controlling effect on the distribution of light in planes transverse to the length of the fluorescent tubes 2. If additional control of the light output of any one of those luminaires is required in the orthogonal plane, this can be achieved by, for example, providing louvres on the forward side of the tube 2 arranged to run across the tube.
  • the luminaires of Figs. 3 to 6 can be provided with any appropriate additional features known to be suitable for use with fluorescent tubes.
  • a loaded polymer material may be provided as described in EP-A-0 811 305 behind the polymeric reflecting film to assist in starting and regulating the fluorescent tube.
  • the rib 7 at the rear of the fluorescent tube 2 serves only to maintain the space between the tube and the reflector shell 5. It does not contribute to the distribution of the light from the luminaire, and could be omitted if some alternative mechanism were provided for maintaining the space between the light source and the reflector.
  • a particular practical advantage of the luminaire constructions illustrated in Figs. 3 to 6 is that the space between the fluorescent tube 2 and the back reflector 3 is closed, along the length of the tube, by the prisms 6 and will consequently remain much cleaner than in a conventional arrangement.
  • the prismatic ribs 6 of the reflectors 3 of Figs. 3 to 6 all have cross-sections in the form of isosceles triangles, other forms of prisms could be employed to vary the distribution of the light from the luminaire.
  • the modifications that may be made to the prisms 6 include, for example, the provision of rounded sides, microstructured surfaces, and an asymmetric cross-section.
  • the prisms 6 of any one reflector need not have the same shape and, depending on the light distribution required, one of the prisms may be omitted.
  • Fig. 7 shows a luminaire with a reflector 3 similar to that of Fig. 5 except that the rib 7 is shortened so that the space between the reflector and the tube at the rear of the latter is decreased. Generally, however, a wider space between the tube 2 and the reflector 3 is preferred because light will then undergo fewer reflections before emerging from the luminaire cavity 4.
  • the shape of the back reflector 3 can also be modified from the generally semi-circular form shown in Figs. 3 to 6.
  • the reflector 3 may, for example, have a parabolic form or comprise flat surfaces.
  • the ribs 6, 7 may be formed in one piece with the reflector shell 5, that is also not essential.
  • the shell 5 could, for example, be formed in metal (which may, in itself, be sufficiently reflective), with the ribs 6, 7 being attached to it. In such a construction, the prismatic ribs 6 would, of course, be formed from an optically-transparent material.
  • Figs. 1 to 7 utilise fluorescent tubes as the light sources, they could use any alternative form of elongate light source provided that this does not completely absorb light that is returned to it by the reflector 3.
  • the light source absorbs none, or substantially none, of the light that is returned to it by the reflector 3.
  • Suitable alternative light sources include large diameter optical fibres and light guides.
  • Fig. 8 is a cross-sectional schematic view illustrating a backlight system 20 that includes a luminaire 11 in accordance with the invention, and a solid light guide 12.
  • the light guide 12 is shown as having a rectangular cross-section, with the elongated luminaire positioned along one edge 12A.
  • the use of a rectangular light guide is not essential, however, and a light guide of any other suitable shape could be used.
  • the reflector 13 of the luminaire is selected so that the output of the luminaire is a narrow, forwardly-directed beam as illustrated in Figs 3 A and 4A, thereby ensuring that as much of the light as possible will enter the light guide 12 through the adjacent edge 12 A.
  • the light guide 12 which may be solid or hollow, has a front surface 14 and a back surface 15.
  • a component such as a polarizer, diffuser, liquid crystal display panel, graphics film or print may be placed above the front surface
  • the light guide 12 further includes some form of light extraction mechanism to direct light from within the guide out through the front surface 14. Examples of known extraction mechanisms include diffusing dots on, or channels in, the back surface 15 of the guide.
  • a particularly advantageous feature of luminaires constructed as illustrated in Figs. 3 to 7 is that they can be very compact in comparison with conventional luminaires employing fluorescent tubes, but will nevertheless provide effective illumination in a wide variety of locations.
  • Luminaires that require less space offer greater design freedom in many areas including, for example, building construction, interior design and electronic displays.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

L'invention concerne un luminaire (1) comprenant un réflecteur (3) définissant une cavité concave allongée dans laquelle se trouve une source lumineuse allongée (2), par exemple un tube fluorescent, en relation espacée avec le réflecteur, ce dernier entourant la source lumineuse sur sa face arrière, afin de réfléchir la lumière provenant de la source et de la faire émettre à partir de la cavité dans une direction dirigée de manière générale vers l'avant. Pour parvenir à une diffusion de la lumière à partir du luminaire (1) à personnaliser afin de satisfaire aux exigences de la situation dans laquelle ledit luminaire doit s'utiliser, le réflecteur (3) comporte, sur des faces opposées de la cavité, une structure prismatique (6) respective, faisant saillie de sa surface intérieure afin d'intercepter et de dévier la lumière émise, de manière générale dans une direction allant vers l'avant, depuis l'espace situé dans la cavité entre la source lumineuse (2) et le réflecteur (3).
EP01987284A 2000-12-11 2001-12-06 Luminaire comprenant une source lumineuse allongee et un retroreflecteur Withdrawn EP1350061A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB0030150.7A GB0030150D0 (en) 2000-12-11 2000-12-11 Luminaire comprising an elongate light source and a back reflector
GB0030150 2000-12-11
PCT/US2001/046583 WO2002048606A2 (fr) 2000-12-11 2001-12-06 Luminaire comprenant une source lumineuse allongee et un retroreflecteur

Publications (1)

Publication Number Publication Date
EP1350061A2 true EP1350061A2 (fr) 2003-10-08

Family

ID=9904831

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01987284A Withdrawn EP1350061A2 (fr) 2000-12-11 2001-12-06 Luminaire comprenant une source lumineuse allongee et un retroreflecteur

Country Status (7)

Country Link
EP (1) EP1350061A2 (fr)
JP (1) JP2004533085A (fr)
CN (1) CN1479849A (fr)
AU (1) AU2002239518A1 (fr)
CA (1) CA2428127A1 (fr)
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WO (1) WO2002048606A2 (fr)

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JP4594158B2 (ja) * 2005-04-25 2010-12-08 株式会社エス・テー・アイ・ジャパン 光源用反射体、光源装置及び照明装置
JP2009545488A (ja) * 2006-08-01 2009-12-24 スリーエム イノベイティブ プロパティズ カンパニー 照明装置
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JP5903950B2 (ja) * 2012-03-14 2016-04-13 三菱電機株式会社 画像読み取り用ライン光源
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GB0030150D0 (en) 2001-01-24
WO2002048606A2 (fr) 2002-06-20
CA2428127A1 (fr) 2002-06-20
JP2004533085A (ja) 2004-10-28
CN1479849A (zh) 2004-03-03
AU2002239518A1 (en) 2002-06-24
WO2002048606A3 (fr) 2003-02-27

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