Illumination – Light source and modifier – Louvered or grid type modifier
Reexamination Certificate
2001-05-08
2002-10-01
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Louvered or grid type modifier
C362S354000, C362S291000
Reexamination Certificate
active
06457844
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The invention relates to a light distributor for a lighting device and a lighting device having at least one light distributor.
The lighting device may consist, for example, of a light, such as, for example, a pendant, built-in, standard or wall light, which has, as a light source, at least one electric lamp, for example at least one tubular and/or U-shaped fluorescent lamp. The lighting device may, however, also be in the form of a luminous-band lighting device which has a rail and at least one row of lamps which follow one another along said rail and, for example, in turn consist of tubular and/or U-shaped fluorescent lamps. The lighting device is intended in particular for use in a room, for example a large office, in which at least one person works at a screen.
2. Description of the prior art
Lighting devices disclosed in EP 0 235 652 A have a light source with a fluorescent lamp and a light distributor arranged under the light source and having a distributor element which consists of a flat sheet-metal piece with a number of holes for the passage of light. In some variants, the sheet-metal piece is provided with downward-projecting collars. The holes for the passage of light are either completely or for the most part cylindrical and, in the latter case, have a section tapering downward from the upper end. The ratio of the lengths to the cross-sectional dimensions of the holes is established so that the light transmitted directly through the holes for the passage of light makes, with a horizontal plane, an angle at least equal to a predetermined stopping angle. If the bounding surfaces of the holes for the passage of light are at least to some extent light-reflecting, light generated by the light source in such a lighting device can, however, be radiated, after being reflected once or several times by the bounding surfaces of the holes for the passage of light, also in “flat”, i.e. almost horizontal, directions through the holes of the distributor element into the room containing the lighting device and directly onto a screen arranged in this room. Such light can moreover be reflected by the screen into the eyes of a person working at said screen and can dazzle said person. Thus, if said bounding surfaces are to some extent light-reflecting, the known lighting devices cannot truly avoid dazzling. If, on the other hand, the bounding surfaces of the holes for the passage of light were to completely absorb the light incident on them, there would be only a low yield of the light generated by the light source.
Other known light distributors have a grid of lamellae which serve as a distributor element and have two edge strips parallel to one another or a frame having four edge strips and a number of lamellae fastened to the edge strips and/or possibly to one another. The edge strips and lamellae consist of thin, light-reflecting sheet-metal pieces. The lamellae are usually a few centimeters apart. Furthermore, the edge strips and lamellae are usually a few centimeters high. Such light distributors therefore have the disadvantage that the grids of lamellae occupy a relatively large height of, for example, at least or about 2 centimeters, which is often undesired. Furthermore, a large number of individual lamellae has to be produced and in particular individually fastened. The production and the assembly of a grid of lamellae are therefore very expensive.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a light distributor which eliminates disadvantages of the known light distributors. The light distributor should in particular make it possible to suppress direct light radiation in undesired directions and nevertheless occupy only a little space, especially only a small height region. The light distributor should furthermore be economical to produce and permit a high light yield.
This object is achieved, according to the invention, by a light distributor for a lighting device, comprising an integral distributor element which has an extensive main section with an incidence side intended for turning toward a light source, a radiation side facing away from said incidence side and a number of holes for the passage of light, wherein each hole has a bounding surface and wherein the holes widen from the incidence side to the radiation side, at least for the greatest part of their bounding surface.
The invention furthermore relates to a lighting device having at least one light distributor, comprising an integral distributor element which has an extensive main section with an incidence side intended for turning toward a light source, a radiation side facing away from said incidence side and a number of holes for the passage of light, wherein each hole has a bounding surface, wherein the holes widen from the incidence side to the radiation side, at least for the greatest part of their bounding surface, and wherein said lighting device has at least one lamp holder for holding at least one electric lamp in such a way that it radiates light to the light distributor during operation.
The invention also relates to a use of the lighting device having at least one light distributor, comprising an integral distributor element which has an extensive main section with an incidence side intended for turning toward a light source, a radiation side facing away from said incidence side and a number of holes for the passage of light, wherein each hole has a bounding surface, wherein the holes widen from the incidence side to the radiation side, at least for the greatest part of their bounding surface, wherein said lighting device has at least one lamp holder for holding at least one electric lamp in such a way that it radiates light to the light distributor during operation and wherein the lighting device is arranged in such a way that all light radiated through the light distributor and out of it makes an angle with a horizontal plane.
REFERENCES:
patent: 2996417 (1961-08-01), Wilson
patent: 3368070 (1968-02-01), Schwartz et al.
patent: 4748547 (1988-05-01), Baker
patent: 4896656 (1990-01-01), Johnson
patent: 6059426 (2000-05-01), Lavy
patent: 36 32912 (1987-04-01), None
patent: 0 235 652 (1987-09-01), None
patent: 0 870 977 (1998-10-01), None
Kunitz Norman N.
O'Shea Sandra
Regent Beleuchtungskoerper AG
Truong Bao
Venable
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