Abstract:
The invention provides in preferred aspects architectural lighting structures that comprise a plurality of tubular elements at least partially embedded into an at least substantially transparent lens structure of a lighting fixture. The lighting fixture is typically a device employed for interior use, particularly residential buildings or commercial buildings such as office buildings. By partially embedding the array or plurality of tubular elements into the transparent lens structure, the fixture can appear as if it is substantially a part of the surrounding surface when the lighting fixture is turned off. Nevertheless, when the light is turned on, light coming from the fixture can still be directed or modified in an appropriate manner, e.g. without detrimental light output reductions), and without the need of an expensive, sophisticated reflector or any necessity of the fixture extending beyond the surrounding surface as has been utilized in certain prior attempts to mask architectural lighting fixtures. Still further, while the light fixture is turned on, an unsightly bulb or glaring reflector can be masked from a viewer&#39;s eye as a result of the partially embedded tubular elements.

Description:
INTRODUCTION  
         [0001]    This invention relates generally to techniques for concentrating or directing the output from lighting fixtures and modifying the fixtures&#39; appearance in the off and/or the on state.  
         BACKGROUND OF THE INVENTION  
         [0002]    Lighting fixtures, e.g. the recessed “can lights” used in architectural lighting, have traditionally used a variety of techniques to efficiently direct or otherwise manipulate their light output. For example, the fixtures may be designed to be recessed into a wall or ceiling, may incorporate reflectors or lenses or may incorporate baffles or shields.  
           [0003]    However, manipulation of the light output or increase efficiency often comes at the price of a less pleasing appearance when the lighting fixture is turned off or on. Recessed “can lights” for example, look like holes in the ceiling plane when they are off; “wall washer” fixtures, i.e. fixtures set into a ceiling and configured to throw light onto an adjacent wall, often project below the surface of the ceiling and are often of low efficiency; reflectors used to direct light downwards can create glare to a viewer&#39;s eye.  
           [0004]    The problem of unattractive lighting fixtures has become worse with the advent of high-efficiency, compact fluorescent bulbs replacing simple incandescent bulbs in many lighting fixtures. These compact fluorescent bulbs, with their large, twisted glass tubes, are unpleasing to the eyes, and since they are much less of a point source than incandescent bulbs, do not lend themselves to simple, efficient reflector design.  
           [0005]    At present, the practical solutions to the above problems are limited. For example, certain grids of vanes have been placed in front of the light source to shield a viewer&#39;s eyes from glare coming from the bulb or its reflector or to make a light look like less of a hole in the ceiling. Sophisticated and precisely shaped reflectors can be incorporated into a compact fluorescent lamp&#39;s fixture to try to direct light from the bulb efficiently in the desired pattern. PAR-type lamps can be mounted at an angle inside a recessed fixture to wash a wall with light without a bulb or fixture hanging below the plane of the ceiling.  
           [0006]    Those approaches each suffer from significant disadvantages. Current grids of shielding vanes can reduce the efficiency or restrict the angle of illumination of a fixture. Sophisticated and precisely shaped reflectors are expensive to manufacture. PAR-type lamps are substantially more expensive than standard-type bulbs.  
           [0007]    Accordingly, it would be highly desirable to have other techniques to manage the light output from a lighting fixture as well as provide an aesthetically pleasing appearance when the fixture is in the either on or off state.  
         SUMMARY OF THE INVENTION  
         [0008]    The invention provides a lighting structure that comprises a plurality of tubular elements at least partially embedded into an at least substantially transparent lens structure of a lighting fixture. The lighting fixture is typically a device employed for interior use, particularly interior commercial or residential buildings. The lens structure may be of any of a number of materials that are employed to disperse or enhance light produced by and/or shield the light producing element(s) of the lighting fixture. For example, the lens structure may be a standard lens element, or may contain a plurality of lens-like or other light modifying elements positioned at the front of a lighting fixture. The lens or lens-like elements direct light coming from the fixture&#39;s light source and reflector outward through the tubular elements.  
           [0009]    By partially embedding the array or plurality of tubular elements into the transparent lens structure, the fixture can appear as if it is substantially a part of the surrounding surface when the lighting fixture is turned off (i.e. light bulb or other light producing elements not emitting light). Nevertheless, when the light is turned on (i.e. light bulb or other light producing elements emitting light) light coming from the fixture can still be directed or modified in an appropriate manner, e.g. without detrimental light output reductions), and without the need of an expensive, sophisticated reflector or any necessity of the fixture extending beyond the surrounding surface as has been utilized in certain prior attempts to mask architectural lighting fixtures. Still further, while the light fixture is turned on, an unsightly bulb or glaring reflector can be masked from a viewer&#39;s eye as a result of the partially embedded tubular elements.  
           [0010]    The invention also includes methods for manufacturing lighting devices of the invention. Those methods comprise in general steps of heating a lens material to at least its glass transition temperature; at least partially embedding an array of tubular elements into the heated lens material; and cooling the lens material with tubular elements embedded therein whereby lens elements form around and/or between the tubular elements.  
           [0011]    Other aspects of the invention are disclosed infra. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 depicts diagrammatically the geometry of a typical situation in which glare to a viewer from an incandescent recessed lighting fixture can occur;  
         [0013]    [0013]FIG. 2 diagrammatically illustrates how a typical recessed lighting fixture can look like a hole in a ceiling&#39;s surface when in the off condition;  
         [0014]    [0014]FIG. 3 depicts diagrammatically the geometry of a typical situation where an observer outside the main area of illumination of a typical compact fluorescent recessed lighting fixture can be exposed to glare and also how an observer inside the main area of illumination can easily see the complex and unattractive bulb;  
         [0015]    [0015]FIG. 4 depicts diagrammatically the geometry of a typical situation in which a grid of tubes installed in front part of a lighting fixture to shield an observer from glare can also reduce the output of the fixture and restrict its angle of illuminating;  
         [0016]    [0016]FIG. 5 depicts a particular embodiment of a structure in accordance with the invention for use in improving lighting fixtures;  
         [0017]    [0017]FIG. 6 diagrammatically illustrates a section through the embodiment of FIG. 5 and is useful in explaining the concept of embedding a grid of tubes into a lens structure;  
         [0018]    [0018]FIG. 7 diagrammatically illustrates how the structure in accordance with the invention is placed in front of a lighting fixture;  
         [0019]    [0019]FIG. 8 diagrammatically illustrates how a lens element embedded into a grid of tubes can collect light coming from one side that would normally hit a grid of tubes alone and that with a single grid without lens element would direct this light downwards through the tubes;  
         [0020]    [0020]FIG. 9 diagrammatically illustrates how a lens structure embedded with a grid of tubes can widen the angle of illumination of light coming from a fixture while still shielding an observer from a direct view of the interior of the fixture;  
         [0021]    [0021]FIG. 10 diagrammatically illustrates how a structure in accordance with the invention can spread essentially collimated light coming from a lighting fixture;  
         [0022]    [0022]FIG. 11 depicts diagrammatically the geometry of a typical “wall washer” type lighting fixture;  
         [0023]    [0023]FIG. 12 diagrammatically illustrates how lens elements embedded with a tilted grid of tubes can direct light to “wash a wall” with light, while at the same time shielding the view of an observer from glare or a view of the interior of the fixture;  
         [0024]    [0024]FIG. 13 diagrammatically illustrates how a lighting fixture incorporating a structure in accordance with the invention can wash a wall with light without extending below the ceiling plane, can make the light look like part of the ceiling and can shield a view or from glare;  
         [0025]    [0025]FIG. 14 diagrammatically illustrates, with a section through the long axis of a compact fluorescent bulb fixture with an inexpensive reflector, how a structures in accordance with the invention can help manage the light output of a fixture that does not have an efficient reflector/bulb combination, while at the same time hiding a direct view of the unsightly interior;  
         [0026]    [0026]FIG. 15 depicts an alternative embodiment of the lens/tube structure;  
         [0027]    [0027]FIGS. 16, 17,  18 , and  19  depict still further alternative embodiments of lens/tube structures;  
         [0028]    [0028]FIG. 20 diagrammatically illustrates how lens elements embedded into a grid of tubes can be stepped in the fashion of a fresnel lens to mimic the effect of a much thicker and more a steeply curved lens;  
         [0029]    [0029]FIG. 21 diagrammatically illustrates how lens elements embedded into a grid of tubes can each have a different purpose than its neighbor;  
         [0030]    [0030]FIG. 22 diagrammatically illustrates how lens elements embedded into a grid of tubes can spread essentially collimated light to illuminate a wider angle without having large amounts of the light blocked by the tubes;  
         [0031]    [0031]FIG. 23 depicts an alternative embodiment for the gathering of the tubes into a grid;  
         [0032]    [0032]FIGS. 24 and 25 depict still further alternative embodiments for the gathering of the tubes into a grid;  
         [0033]    [0033]FIGS. 26, 27 and  28  are useful in explaining the concept of pre-forming the shape of lens structure so that when a grid of tubes is pressed into it, material flowing away from the tube walls will form the desired final lens shape; and  
         [0034]    [0034]FIG. 29 depicts a still further embodiment for use with a skylight in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]    Referring now to the Drawings, as can be seen in FIG. 1, a typical lamp fixture  32  (shown here as a recessed into a ceiling  34 ) projects light from a bulb  36  reflector  30  outward in a zone  38  to illuminate a desired area. Although the bulk of the light, as shown by exemplary rays  40 , may stay within the desired illumination zone of an angular spread α some light, as shown by exemplary ray  42 , can cause glare for an viewer  37 .  
         [0036]    As can be seen in FIG. 2, another problem that can occur with a lighting fixture  32  that is recessed into a surface, such as a ceiling  34 , is that in the off state, it can look unpleasingly like a hole in the plane of the ceiling  48  to an viewer  37 .  
         [0037]    As FIG. 3 illustrates, the aesthetic problems of recessed lights  32  has become worse with the advent of energy efficient compact bulbs  46 . The bulbs  46  themselves are often in the form of large, twisted tubes  48  that present an unpleasing aspect to a viewer  50 . In addition, the large bulbs  48  are less of a point source than incandescent bulbs and thus require expensive, carefully shaped reflectors  30  to effectively obtain an illumination pattern (as shown by exemplary rays  40 ) over a desired zone  38  of angle θ. In spite of expensive reflectors  30 , such fixtures are often even more prone to glare (as shown by exemplary ray  42  to a viewer  37 ).  
         [0038]    [0038]FIG. 4 shows a proposed technique for preventing glare by the use of a grid of tubes  52  positioned in front of a fixture  32 . This grid  52  shields a viewer  37  from glare by blocking off-axis light as shown by exemplary ray  42 . In addition, when the lighting fixture is in the off state, the grid helps keep the fixture from looking like a hole in the plane of the ceiling. However, the grid also reduces the efficiency of the fixture by blocking light, as shown by exemplary rays  54 , that would otherwise be part of the output as shown by exemplary rays  40 . Thus the illumination zone  38  is reduced to angle β.  
         [0039]    [0039]FIG. 5 shows one preferred embodiment of a structure in accordance with the invention for improving lighting fixtures. As seen therein, a grid of tubes  56  is partially embedded into the a lens plate  58 , having a configuration which permits the structure to be attached, in a suitable manner which would be well known to the art, at the front of a lighting fixture  32  (not shown). FIG. 6 shows a section through this embodiment, detailing how the grid of tubes  56  is embedded into the lens material  58  with lenslettes  70 , which will be discussed below. FIG. 7 shows how the structure  60  is places n front of fixture  11 . Suitable grid of tubes are described herein and have been described in U.S. Pat. No. 4,929,055 and PCT/US93/11459.  
         [0040]    As seen in FIG. 8, a section through the structure of one preferred embodiment, by refracting light that strikes it from one side (as shown by exemplary ray  62 ), a suitable lens plate  58  can direct light that would normally be blocked (as shown by exemplary ray  54 ) by the grid of tubes  56  downwards through the tubes (as shown by exemplary ray  64 ), thus increasing the amount of light  40  that is passed out of the lighting fixture.  
         [0041]    Thus, as can be seen in FIG. 9, when a structure of a preferred embodiment  60  is placed in front of a fixture  32 , the fixture can maintain the desired illumination zone of an angular spread α that it had without a grid of tubes, as shown in FIG. 1, while at the same time passing a larger amount of light  40  than a fixture  32  (as shown in FIG. 4) with only a grid of tubes  52 . Also, the structure  60  will shield a viewer  37  from glare, and when the fixture is in an off condition, the grid of tubes  56  will keep the fixture from looking like a hole in the ceiling  34 .  
         [0042]    [0042]FIG. 10 shows another preferred embodiment of the structure used with a fixture  32  that has a parabolic reflector  66 . The light coming from the fixture (as shown by exemplary rays  68 ) are essentially collimated, and the lenslettes  70  of the lens plate  58  refract this light outward in a spreading pattern (as shown by exemplary rays  40 ) over an illumination angle.  
         [0043]    [0043]FIG. 11 shows a proposed technique of the prior art for a lighting fixture  32  that functions as a “wall washer.” This kind of fixture is generally recessed into a ceiling  34  and uses a small, angled surface  72  to reflect light (as shown by exemplary ray  40 ) from a bulb  36  onto an adjacent wall  74  to illuminate it. This type of fixture has a number of problems: for example, more than half of the light from the bulb  36  (as shown by exemplary rays  76 ) are simply absorbed by the inside of the fixture&#39;s housing  58  and not projected outward to light the wall  74 . Moreover, these fixtures typically physically extend a distance  80  below the plane  82  of the ceiling  34 . Furthermore, when in the off state, these fixtures typically look like a hole in the ceiling.  
         [0044]    Another preferred embodiment of the invention can solve these problems with existing “wall washer” type light fixtures. FIG. 12 shows a section of a structure  60  where the grid of tubes  56  is embedded into the lens plate  58  at an angle λ to the axis  84  of the lighting fixture  32 . With a suitable lenslette shape  74 , which would be well known to the art, essentially collimated light coming from the bulb and reflector (as shown by exemplary ray  40 ) will be refracted off at an angle μ.  
         [0045]    [0045]FIG. 13 shows an overall view of one preferred embodiment of a “wall washer” type lighting fixture  32  in accordance with the invention. The structure  60  is placed at the front of the fixture and takes light coming from the bulb  36  and off the reflector  30  (as shown by exemplary rays  40 ) and refracts it so that the light  40  is directed at the wall  74 . A lighting fixture such as  32  is relatively simple to fabricate, and therefore less expensive than existing “wall washer” type fixtures as shown in FIG. 11. In addition, it should be more efficient than the type of fixture shown in FIG. 11, since a large portion of the light is not simply absorbed by the housing as it is in FIG. 11. Furthermore, because the grid of tubes  56  are at an angle to a viewer  44 , the viewer will see the fixture as part of the ceiling plane  82  when the light is in both the on and the off state, and therefore the fixture will not appear as a hole in the ceiling  34 .  
         [0046]    With a lighting fixture using an energy efficient compact fluorescent bulb as shown in FIG. 14 (a sectional view perpendicular to the long axis of the bulb  46 ), one preferred embodiment of a structure  60  in accordance with the invention can be figured such that the lenslettes  70  at the edge of the fixture are shaped such that the light (as shown by exemplary rays  42 ) coming at an angle from the bulb  46  which lies in the center of tubes, a maximum amount of the light being directed into a preferred illumination zone  38  (as shown by exemplary rays  40 ). In this way, a less expensive reflector  30  can be used while still maintaining good efficiency. The structure  52  also shields the viewer  44  from an unpleasant direct view of the interior of the fixture when the fixture is in the off or on state.  
         [0047]    In one embodiment of the present invention, as shown in detail in FIG. 15, the lenslettes  70  that make up the structure  60  have a convex outer surface  86  and a planar inner surface  88 .  
         [0048]    In a further embodiment as shown in detail in FIG. 16, the lenslettes that make up the structure  60  have a planar outer surface  86  and a convex inner surface  88 .  
         [0049]    In a further embodiment as shown in detail in FIG. 17, the lenslettes that make up the structure  60  have convex outer  86  and inner  88  surfaces.  
         [0050]    In a further embodiment as shown in detail in FIG. 18, the lenslettes that make up the structure  60  have concave outer  86  and inner  88  surfaces.  
         [0051]    In a further embodiment as shown in detail in FIG. 19, the lenslettes that make up the structure  60  have concave outer  86  and a convex inner  88  surfaces.  
         [0052]    In yet a further embodiment, FIG. 20 shows a lens structure  60  where the lenslettes  70  are stepped, in the manner of a fresnel lens, so that the lens plate structure  60  can mimic the performance of a much thicker and more steeply curved, lens  90 .  
         [0053]    In a yet a further embodiments, FIG. 21 shows a lens structure  50  where each of the lenslettes  70  can have a different purpose or configuration than its neighbor, to produce varied lighting effects.  
         [0054]    As seen in FIG. 22, a section through the structure of yet another embodiment, the lenslette  70  has a short focal length f such that light coming from the bulb and reflector of the fixture (as shown by exemplary rays  40 ) in an essentially collimated manner can be brought to a focal point  92  inside the embedded tube  56  and then made to spread out widely (as shown by exemplary rays  40 ). In this way the structure  60  can shield the view of the inside of the fixture  32  and also keep the fixture  32  from looking like a hole when it is in the off state, while still giving the fixture  32  a wide angle of illumination υ.  
         [0055]    As used herein, the term grid of tubes is deemed to mean an element of generally tubular configuration having any selected geometrical cross-sectional shape. Thus, the tubular elements  57  in FIG. 5 are shown as being square in cross-section, although other shapes can be used, e.g., other rectangular configurations, a triangular configuration, a hexagonal configuration, etc., such elements capable of being suitably nested to form a substantially unifonn honeycomb or grid-like overall structure. Suitable grid of tubes or tubular elements are also disclosed in U.S. Pat. No. 4,929,055 and PCT/US93/11459, both incorporated herein by reference. Also, references herein to a grid of tubes or tubular elements being partially embedded in a lens indicate that the tubular elements extend to within the lens substrate as exemplified in FIG. 26, rather than merely abutting the lens surface.  
         [0056]    The tubes that make up the grid  56  can have a number of different configurations, though the cross sectional shape of the tubes would generally be selected to that they could be nested into a honeycomb type arrangement. FIG. 23 shows another preferred embodiment of a tubular grid structure  56  with tubes of a rectangular cross section  96 . In yet another embodiment, FIG. 24 shows a structure  60  within an arrangement of concentric tubes  57  held in position by horizontal and vertical vanes  98 . In yet another embodiment, FIG. 25 shows a structure  60  with tubes  57  of a hexagonal cross section.  
         [0057]    One method of embedding the grid of tubes  56  into the lens plate  58  would be to heat the lens plate  58  to its state-change temperature (Tg) and then pressing the grid of tubes  56  into the lens. The problem with this method when seeking to form lenses is that the material displaced by the encroaching grid  56  can deform the pre-molded lenslette shapes on the lens plate. FIG. 26 shows, a desired final form of a structure  60  incorporates a lens plate  58  with an embedded grid  56  the lenslette  70  having the desired final form.  
         [0058]    According to an example manufacturing method of the invention, as exemplified in FIG. 27 when there is a lens plate  58  that is to have a grid of tubes  56  embedded into it, the lenslettes  70  can be formed with a lenslette shape  100  such that when, as shown in FIG. 28, a grid  56  is pushed into the lens plate  58  heated to its glass transition temperature (Tg) or somewhat in excess thereof, the material displaced  102  by the grid will flow back and fill in the designed final form of the lenslette shape  100 .  
         [0059]    The structure  60  also can be placed in a ceiling  34  as shown for example in FIG. 29. In that Figure, room  104  is below a skylight  106  (a type of lighting fixture). During the night, when a skylight normally looks black or dark, the structure  60  will look light and essentially part of the ceiling. During the day, light rays  108  from the sun  110  can be spread through a wider angle of rays  112  to make a light source that will be more pleasing and more evenly illuminate a room  104  than an unmodified skylight would.  
         [0060]    Structures in accordance with the invention can be relatively easily fabricated for use on many different types of lighting fixtures. In addition to interior architectural lighting applications such as residential or commercial buildings, the lighting fixtures of the invention can be used in theatrical lighting or the like.  
         [0061]    Other modifications of the invention will occur to those in the art within the spirit and scope of the invention. Hence, the invention is not to be considered as limited to the particular embodiments discussed and shown in the figures, except as defined by the appended claims.