Patent Application
20090161367
The present invention relates generally to luminaires and, more particularly, to three dimensional reflectors for luminaires that more efficiently produce a desired light distribution pattern on a surrounding surface.
Luminaires are designed to produce a predetermined light distribution pattern in an area to be illuminated, such as in parking lots, along roadways, or in other areas requiring broad or focused illumination of a surface. Luminaires generally include a housing or enclosure that supports a lamp socket, a high-intensity lamp source mounted in the lamp socket, a light reflector mounted behind and/or around the lamp source, and other electrical hardware necessary to energize the lamp source. The illumination pattern created by the luminaire is generally defined by the shape of the light reflector mounted in the luminaire, as well as the position of the light source relative to the reflector. The reflector can form a partial enclosure about the source of light so that the inner surfaces of the reflector direct reflected light through an opening formed in a lower portion of the luminaire housing.
In the past, one-piece reflectors have been fabricated by molding or otherwise forming a flat piece of metal or other suitable reflective material into a desired reflector shape. The reflector can be made by forming a sheet of reflective material between male and female dies that have cooperating three-dimensional surfaces defining the reflector shape. Alternatively, the reflector may be formed by hydroforming the sheet of reflective material over a three-dimensional male form that defines the reflector shape. In another method, the reflector may be spun by contouring a sheet of reflective material over a revolving male mandrel with a pressure tool to conform the sheet to the shape of the mandrel. In yet another method of fabricating reflectors, the sheet of reflective material may be formed using a press brake or other forming machine that successively bends the sheet along predetermined fold lines into a series of planar facets that approximate a desired curved surface of the reflector.
Reflectors have also been fabricated from multiple sheets of reflective material that have been individually formed and then assembled together to produce a desired reflector shape. The individual parts of the multi-component reflector have either been joined together through fastening hardware, or other suitable structures, prior to mounting the assembled reflector in a luminaire housing, or the reflector components have been mounted individually within the luminaire housing to form the three-dimensional reflector shape within the housing.
More recently, as described in U.S. Pat. No. 6,464,378, reflectors have been fabricated from a single sheet of reflective material that has been punched out in a single hit die press, or other cutting operation, to form a series of integral reflective panels. The reflective panels are adapted to be joined together so that each of the panels can be folded by hand into an edge-abutting relationship with an adjacent panel to form a predetermined three-dimensional reflector shape. The sheet of material is relatively thin to allow one or more of the panels to be curved by hand to define curved reflective surfaces, which can be joined to adjacent panels through perforated fold lines. These reflectors are efficient to make and store, and can be easily assembled into a three-dimensional shape at an assembly site or in the field.
In most outdoor lighting installations, a plurality of luminaires are mounted onto light poles of generally standard height to provide a particular ground illumination pattern. The illumination needs of a particular parking lot, roadway or other outdoor area are met by positioning the plurality of mounted luminaires in a spaced relationship about the surface to be illuminated. Oftentimes, in a lighting installation, the spacing of the mounting poles may cause the luminaires to throw light beyond the area of need, and/or produce an uneven illumination of the ground, road or parking area. This is particularly the case with traditional IESNA Type V luminaire reflectors which produce a circular symmetrical light distribution pattern. When a plurality of luminaires having these conventional reflectors are used to illuminate a large surface area, such as a parking lot, dark areas, or corners, are formed between the illumination areas of adjacent luminaires. In many applications, a higher intensity or higher wattage light source is required to compensate for the loss of light in these dark areas, or because of uneven lighting between the luminaires. Alternatively, additional luminaires and mounting poles may be required to eliminate the “dark areas” and provide adequate, uniform lighting to all of the surface area.
Accordingly, it is desirable to have a luminaire assembly that provides a more even and effective distribution of a majority of the light that is emitted from a lamp to light particular outdoor areas. Additionally, it is desirable to have a luminaire reflector that provides a larger, more effective, light distribution pattern without increasing the lumens or wattage of the light source. Further, it is desirable to have a luminaire reflector that provides a square light distribution pattern in order to eliminate dark corners within the illumination area. Furthermore, it is desirable to have a luminaire reflector that provides a more efficient light distribution pattern while also minimizing the glare produced by the luminaire. Still further, it is desirable to have a high efficiency luminaire reflector that can be rapidly and consistently formed from one or more sheets of reflective material. Additionally, it is desirable to have a high efficiency luminaire reflector that allows greater spacing between adjacent light poles while maintaining the same level of illumination or, alternatively, that provides an equal level of illumination with existing light pole spacing but using lower wattage light sources to reduce the overall energy consumption.
In response to these needs, the present invention provides a reflector for a luminaire in which the reflective panels are configured to provide greater, more uniform illumination from a designated wattage lamp source. In particular, the present invention provides a reflector for a luminaire that has a light source securable therein. The reflector comprises a plurality of reflective panels retained in a three-dimensional concave reflector shape. The reflector shape defines a first opening for the light source and a second opening for emitting light in a predetermined distribution pattern. Each of the reflective panels has an inwardly-facing, smooth and continuous reflective surface between the light source opening and the light emitting opening. The plane of the light emitting opening is perpendicular to nadir. The reflective panels are curved inward in the direction of nadir adjacent to the light emitting opening to increase the distance of the reflected light beam.
Additionally, the present invention provides a luminaire assembly comprising a luminaire housing and a reflector mounted within the luminaire housing. The reflector comprises a plurality of reflective panels retained in a three-dimensional concave reflector shape that defines a light source opening and a light emitting opening for emitting light in a predetermined distribution pattern. The light emitting opening occupies a plane perpendicular to nadir. The reflective panels are curved in the direction of nadir to form a reduced diameter at the light emitting opening. The luminaire assembly may also include a light source socket mounted to the reflector. A light source is attached within the socket for emitting light upon energizing the source. The lamp socket is mounted so as to position the light source within the apex of the reflector.
The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.
Referring now to the drawing figures, in which like numerals indicate like elements throughout the views,
Reflector 22 is positioned about lamp 32 to direct or reflect light in a predetermined light distribution pattern through reflector opening 34. As those of ordinary skill in the art will appreciate, luminaire housing 24 can be formed in a variety of shapes and sizes depending upon the particular lighting application or need. Luminaire 20 is typically mounted on a pole or other supporting structure to raise the luminaire assembly sufficiently above the surrounding surface to provide a broad light distribution pattern on the surface. It will be appreciated that luminaire 20 can also include a transformer and other electrical hardware for connecting the luminaire to a source of power and for energizing lamp 32 via suitable wiring connected to socket 26. A typical luminaire assembly is described in U.S. Pat. No. 6,464,378, which is hereby incorporated herein by reference.
Luminaire reflector 22 is formed from a unitary sheet of reflective material in a laser cutting operation, or other similar type of cutting method known in the art. The sheet of reflective material may be polished, anodized aluminum (also known as “specular aluminum”) semi-specular aluminum, or another type of reflective material that has the desired reflective and other structural properties for a reflector. A preferred material for the reflective sheet is Alanod Miro-4, a highly specular anodized aluminum having a minimum 95% reflectance, which is available from ALANOD Aluminum-Veredlung GmbH & Co. KG. The reflective sheet preferably has a thickness of approximately 0.02 inch to enable the sheet to be folded and curved by hand, or a manually-operated tool, into a desired three-dimensional reflector shape. To form a reflector, the sheet of reflective material is cut into a desired pattern in a single dimension. Following the cutting operation, multiple, unassembled reflectors may be stacked and stored easily in the single dimension configuration.
As shown in
Panels 44, mounting flanges 50, center support ring 46 and collar segments 48 generally lie in a common plane after the reflector pattern is cut from the reflective sheet. In the illustrated embodiment, panels 44 are configured in different widths along the base (the portion proximate the mounting flanges), depending upon the light-reflecting performance desired from the panel. Each panel 44 is formed with a pair of spaced, elongated, non-linear free edges 60 that are adapted to abut the non-linear free edges 60 of adjacent panels when the panels are folded to form the assembled reflector 22 shown in
In addition to the locking members on panels 44, mounting flanges 50 include tabs 70 and notches 72 to hold the mounting flanges together within the assembled reflector. A tab 70 and notch 72 is formed in a spaced relationship along the outer edge of each of the flanges 50b-50o to allow the tab from one flange to mate with the notch of the adjacent flange when the flanges are brought together during folding. Mounting flange 50a is the initial flange that is bent during folding of the reflective sheet into an assembled reflector. As such, mounting flange 50a includes a pair of notches 72 that are spaced apart along the outer edge of the mounting flange, so that the notches may be brought into engagement with tabs from both adjacent mounting flanges (50b and 50p) during folding, to lock the adjacent flanges to the initial flange 50a. Similarly, mounting flange 50p has a pair of tabs 70 that are spaced apart along the outer edge of the mounting flange. Mounting flange 50p is the last flange to be folded during the reflector assembly. The additional tab 70 on the outer edge of mounting flange 50p enables the flange to be joined to notches 72 on both of the adjacent flanges, i.e. the immediately prior folded mounting flange 50o and the initially folded mounting flange 50a.
To assemble a three-dimensional reflector 22, a first panel 44a of the reflective sheet shown in
As panel 44b is folded and shaped, the panel is brought into an edge abutting relationship with the adjacent first panel 44a. The positioning tabs 62 along the free edges of the panels 44a and 44b are brought together so that the positioning tabs of each curved panel overlie the abutting marginal edge of the adjacent curved panel to hold the free edges of the panels together in an abutting relationship. Additionally, a locking tab 64 on one of the panel edges 60 is brought into engagement with, and bent into and through a slot 66 on the adjacent panel edge to further lock the abutting panels together. In the embodiment shown in
Following joining of panels 44a and 44b, mounting flange 50b is folded outward along fold line 84 into a mounting flange forming position substantially coplanar with the first mounting flange 50a. When fully folded, a side edge of mounting flange 50b overlies an adjacent side edge of mounting flange 50a, as shown in
Following the folding of second panel 44b and mounting flange 50b, the next adjacent panel 44c is similarly shaped and folded so that a free edge of the panel abuts and is secured to the free edge of the previous panel 44b through positioning tabs 62 and tab/slot pairs 64, 66. Similarly, the mounting flange 50c is folded to overlie the previous mounting flange 50b with the locking tab 70 on flange 50c registering with the locking notch 72 on flange 50b. In this position, the locking tab is bent around and through the locking notch to secure the mounting flanges 50b, 50c together.
The remaining panels 44d- 44p are similarly folded and shaped in a continuously curving manner, moving in a counter-clockwise direction, to form the three-dimensional reflector shape. As each of the remaining planar panels 44d-44p is folded into an edge abutting relationship with the previous panel, the panel is shaped, in the manner described above, to form a smooth, continuously-curved, inward concave reflective contour from the collar 46 to the mounting flange 50. After each panel is folded and shaped, the panel is secured to the next previous panel through positioning tabs 62 and locking tabs and slots 64, 66. Similarly, the remaining mounting flanges 50d-50o are each folded outwardly, following the shaping of the attached panel, to engage and lock onto the adjacent mounting flange. Mounting flange 50p of panel 44p is the last flange folded, with the final locking tabs 70 (on mounting flange 50p) registering with the adjacent locking notches 72 on the initial mounting flange 50a and the next previous mounting flange 50o.
It can be appreciated that the panel and flange securement means described herein cooperate upon assembly of reflector 22 to retain a self-standing three-dimensional reflector shape. Those of ordinary skill in the art will appreciate that other locking structures and folding configurations are possible to form and retain the reflector 22 in its self-standing reflector shape without departing from the spirit and scope of the present invention. Likewise, the order in which the panels are folded and secured together can be varied without departing from the scope of the invention. Following the folding and securing together of panels 44a-44p and mounting flange 50a-50p, collar segments 48 are folded along the fold lines formed by slots 56, into the interior of the assembled reflector 22. Preferably, segments 48 are folded back towards the panels 44 at approximately a 135° angle. When folded into the interior of the reflector, segments 48 form a plurality of light diffusing surfaces about the perimeter of light source opening 30. Collar segments 48 prevent light from reflecting from the apex of the reflector straight down through opening 34 and forming hot spots or striations of light on the surface below.
Traditionally, IESNA Type V luminaire reflectors have been designed such that the diameter of the reflector, taken along a line perpendicular to nadir, increases in the direction of the light emitting opening. Typically, as shown in
In the reflector of the present invention, however, the lower edge of the reflective panels is curved inwardly towards nadir, in order to reduce the diameter of the reflector at the light emitting opening, and create a secondary reflective surface within the reflector. This secondary reflective surface reflects light that has been initially reflected from the smooth, continuously-curved surfaces in the apex of the reflector, as well as directly reflects light emitted towards the bottom of the reflector, as shown in
In the present invention, greater control and redirection of the emitted light is also achieved by raising the level of the light source within the reflector. Raising the light source within the apex of the reflector enables additional light to be reflected off of both the upper, apex reflecting surfaces, as well as the lower, secondary reflective surface, as indicated by the light ray lines in
As shown in
The luminaire reflector embodiment described above has energy efficiencies over luminaires using conventional Type V reflectors due to the increased spread of the reflected light and the reflection of light into corners to produce a substantially square illumination pattern. Accordingly, the present inventive reflector can be used to obtain an increased area of illumination as from a conventional reflector that produces a circular illumination pattern, while using substantially the same power wattage. Alternatively, the present inventive reflector can be used to illuminate approximately the same size area as a conventional IESNA Type V reflector, while using approximately 33% less power. The energy saving advantages of the present inventive reflector can be observed through comparison of iso-footcandle plots for luminaires using the present inventive reflector and a typical, conventional, IESNA Type V reflector. The iso-footcandle plots in this example were both made using a 120,000 lumen HID lamp in a luminaire assembly mounted at a height of 42 feet.
The pattern in
While the present invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. The size of the reflector, as well as the placement of the light source within the reflector, may be varied depending upon the particular lighting level and illumination pattern sought to be achieved. Furthermore, the reflector has been described as having 16 planar reflective panels. However, many of the features of the present invention can be achieved with a reflector having a different number of panels. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broadest aspects is, therefore, not limited to the specific details, representative apparatus and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.
