Abstract:
A lighting device includes a housing, a light emitting device, and an optical array. The housing has a base and the light emitting device is connected to the base for producing a light output. The optical array includes a lens and removably connects to the base. The optical array is repositionable on the base to modify the light output.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. § 119 (e) of U.S. Provisional Application Ser. No. 62/054,750, filed Sep. 24, 2014, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    Various embodiments disclosed herein generally relate to the field of lighting and luminaires utilizing light emitting diodes (LEDs) to facilitate desired illumination. More particularly, embodiments provide optical components for use with one or more LED light sources, or arrays of such LED light sources, and luminaires incorporating such optical components and LED light sources. Further embodiments include methods of illumination where the configuration of respective optical components is field-adjustable to facilitate different desired light patterns emitted from the luminaire. 
       BACKGROUND 
       [0003]    Recently, commercial, as well as residential, lighting applications have been transitioning to the use of LEDs where arrays of LEDs and LED modules provide illumination in applications such as street lighting, office building lighting, and many other outdoor and indoor applications. 
         [0004]    LEDs perform well in the industry, but there are often problems related to aiming the light output from LEDs in a desired direction and pattern to illuminate a particular desired object or area. In general, LEDs emit light in all directions, away from the circuit board on which the LEDs typically reside. As a result, a significant amount of the emitted light is often times not directed towards the specific desired area of illumination. 
       SUMMARY 
       [0005]    According to an exemplary embodiment, a lighting device includes a housing, a light emitting device, and an optical array. The housing has a base and the light emitting device is connected to the base for producing a light output. The optical array has a lens and removably connects to the base. The optical array is repositionable on the base to modify the light output. 
         [0006]    According to another exemplary embodiment, an optical array includes a body portion and a plurality of lenses extending from the body portion. Each lens has a cavity for receiving a light emitter. The plurality of lenses combine to produce an asymmetric light output and the body portion is capable of being rotated to change the direction of the light output. 
         [0007]    A further exemplary embodiment includes A method for altering the light emission pattern of an LED luminaire. An optical array is loosened from a housing of a luminaire. The luminaire has a light emitter with a first LED and a second LED. The optical array has a lens associated with the first LED. The optical array is rotated relative to the first and second LEDs. The first lens aligns with the second LED after the optical array is rotated. The optical array is connected to the housing. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    The aspects and features of various exemplary embodiments will be more apparent from the description of those exemplary embodiments taken with reference to the accompanying drawings, in which: 
           [0009]      FIG. 1  is a bottom view of a lighting device including a rotatable optical array in accordance with an exemplary embodiment; 
           [0010]      FIG. 2  is a bottom perspective view of the lighting device shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a bottom perspective view of the lighting device shown in  FIG. 1  with the rotatable optical array removed; 
           [0012]      FIG. 4  is a top view of an optical array in accordance with an exemplary embodiment; 
           [0013]      FIG. 5  is a side elevation view of the exemplary optical array of  FIG. 4 ; 
           [0014]      FIG. 6  is a front elevation view of the exemplary optical array of  FIG. 4 ; 
           [0015]      FIG. 7  is a bottom perspective view of the exemplary optical array of  FIG. 4 ; 
           [0016]      FIG. 8  is a side elevation view of the exemplary optical array of  FIG. 4 ; 
           [0017]      FIG. 9  is a bottom view of the exemplary optical array of  FIG. 4 ; 
           [0018]      FIG. 10  is a sectional view of the optical array of  FIG. 4  taken along line  10 - 10 ; 
           [0019]      FIG. 11  is a sectional view of the optical array of  FIG. 4  taken along line  11 - 11 ; 
           [0020]      FIG. 12  is a diagram illustrating an outdoor luminaire emitting a symmetric illumination pattern; 
           [0021]      FIG. 13  is a diagram illustrating an outdoor luminaire emitting an asymmetric illumination pattern; 
           [0022]      FIG. 14  is a top perspective view of another optical array in accordance with an exemplary embodiment; 
           [0023]      FIG. 15  is a bottom perspective view of the exemplary optical array of  FIG. 14 ; 
           [0024]      FIG. 16  is an exploded view of the exemplary optical array of  FIG. 14 ; and 
           [0025]      FIG. 17  is an enlarged, sectional view of the exemplary optical array of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0026]    Referring to an exemplary embodiment shown in  FIG. 1  a lighting device, or luminaire  10  includes a round light housing  12  having an upper portion made of heat conductive material such as aluminum or other appropriate material. A base  14  is connected to the upper portion by a fastener or other attachment mechanism, for example by two screws  16 . In an exemplary embodiment the base  14  is a heat sink made of an appropriate heat conductive material sufficient to convey heat generated by LEDs  18  disposed on a printed circuit board under an optical array  20 . The exemplary lighting device  10  is suitable for outdoor lighting applications where the luminaire can be mounted, for example, to a pole, the side of a building, or other structure, although features described herein can be incorporated into other types of lighting devices. 
         [0027]    According to various exemplary embodiments, a secondary optic (not shown) could be installed to housing  12  by a fastener or other attachment mechanism. For example, three holes  21  are provided in housing  12  for receiving corresponding screws to attach a secondary optic, such as a diffuser, etc. Such a secondary optic also operates as a protection mechanism to protect the LEDs and optical array from damage caused by the environment. 
         [0028]    The optical array  20  is connected to the base  14  by a fastener or other attachment mechanism, for example screws  22 . As shown in the exemplary embodiment of  FIG. 1 , optical array  20  is formed as a unitary piece of material, such as acrylic or some other appropriate optic material. Lenses  24  are integrally formed with the body of the optical array  20  and each lens  24  corresponds to a respective LED  18 . More particularly, each lens  24  directs the light generated by its corresponding LED  18  in a predetermined light pattern based on the specific design of the lens  24 . An overall light pattern is then generated by the composite of all individual light patterns generated by the LEDs  18  and their respective lenses  24 . The optical array  20  and integral lenses  24  can be made from a substantially clear or translucent material. The exemplary embodiment of  FIGS. 1-11  show an optical array  20  with a substantially square configuration utilizing nine lenses  24 . Other embodiments can utilize different sizes, shapes, and configurations of an optical array  20  having any number of lenses  24 . 
         [0029]      FIG. 3  shows the housing  12  with the optical array  20  removed, exposing the light emitting device  26 . In this exemplary embodiment, the light emitting device  26  is a plurality of LEDs  18  mounting on a printed circuit board (PCB)  28 . The PCB  28  is mounted to the base  14  base by one or more mechanical fasteners, for example four screws  30 . Heat generated by LEDs  18  is conducted to the base  14  and housing  12  where it is dissipated. As best shown in  FIGS. 2 and 3 , the housing  12  includes heat fins, or other structures,  32  which increase the surface area of the housing and provide effective heat dissipation by allowing air to pass through and around the fins  32 . Dashed line  34  represents the outline of where optical array  20  would be mounted. Holes in the base  14  receive screws  22  when optical array  18  is installed. 
         [0030]      FIGS. 4-11  show a rotatable optical array  20  in accordance with an exemplary embodiment. The optical array  20  includes nine lenses  24  arranged in a symmetrical 3×3 array of three rows and three columns. The optical array  20  also includes one or more clearance portions  36 . Each clearance portion  36  encloses a respective area in which electrical wires, connections, or other components can reside without interfering with the bottom surface of the optical array  20 . In an exemplary embodiment, the number of clearance portions  36  are equal to the number of sides of the optical array  20 . 
         [0031]    According to a further embodiment, an orientation marker  38  is provided on the face of optical array  20  to indicate a given initial orientation of the optical array when installed in a luminaire. For example, in the embodiment shown each lens  24  is formed such that the light emitted from the respective LEDs is directed generally towards, or in the same direction as, the orientation marker  38 . Each lens  24  is also formed to spread the emitted light in an asymmetric pattern, discussed further below. 
         [0032]    Under certain circumstances it may become desirable to modify the light pattern emitted from the luminaire  10 . For example, a user could desire to change the positioning or direction of the emitted light without reconfiguring or removing the luminaire  10  or the light emitting device  24  which can include complicated structural and electrical modifications. According to various exemplary embodiments, the optical array  20  can be rotated on the base  14  to allow a user to easily modify the light output. 
         [0033]    To rotate the light pattern, optical array  20  is adjusted within or removed from the luminaire  10 , for example, by unscrewing screws  22  which are securing the optical array  20  to the base  14 , and rotating the optical array by 90 degrees. Indexing posts  40  align with corresponding holes  41  in the PCB  28  to assist in aligning the optical array  20  to the PCB  28 . For example, when indexing posts  40  mate with the corresponding indexing holes  41 , each lens  24  aligns with a corresponding LED  16 . Because the optical array  20  produces an asymmetric distribution, when the array is rotated, the light pattern also rotates. 
         [0034]      FIGS. 7-9  illustrate the underside of the optical array  20  in accordance with an exemplary embodiment. As shown, a groove  42  is formed around the perimeter of optical array  20 . A gasket made of rubber or other appropriate pliable material is placed within groove  42 . When the underside of optical array  20  is placed in contact with the heat sink  14  and screws  22  are secured, a tight seal is formed by the gasket, resisting penetration of water and other foreign material within the area bounded by the gasket. 
         [0035]      FIGS. 10  and ii illustrate a cross-section of the optical array  20 . As shown, each lens  24  includes a cavity  44  in which a corresponding LED  18  is accommodated. Further, clearance portions  36  are formed as embossments and each creates a bubble-like enclosure in which wires, connectors, or other electrical components can reside when optical array  20  is installed. According to the embodiment shown, the bottom side of optical array  20  contacts the upper side of PCB  28  when optical array  20  is installed. It is noted that according to one or more embodiments the pressure exerted by optical array  20  on PCB  28  when screws  22  are secured is sufficient to maintain adequate contact between the PCB  28  and base  14 . That is, in certain embodiments a cavity in the underside of optical array  20  is sized such that PCB  28  fits snugly into the cavity and when screws  22  are fastened to base  14  the PCB  28  is forced into contact with the base and adequate heat transfer therebetween is enabled. 
         [0036]    LEDs emit light in all directions. When no optical array or secondary optic is provided that alters the emitted light pattern from the LEDs, or when spherical lenses are used in the optical array, a symmetric light pattern is emitted from a luminaire housing.  FIG. 12  illustrates such a symmetric light pattern  50  emitted from a luminaire  52 . In the embodiment shown in  FIG. 12 , a secondary optic is provided primarily to protect the LED light source from the exterior environment and does not alter the shape of the emitted light pattern. Thus, very little, if any, alteration to the light pattern emitted from the LEDs occurs. As a result, light is emitted downward from the luminaire  52  to create alight pattern  50  which is essentially circular in shape centered about an axis originating at the center of luminaire  52  and directed straight down to the ground. The circular light pattern  50  illuminates the ground equally in all directions, e.g., approximately a 20 foot radius from the axis in  FIG. 12 . 
         [0037]      FIG. 13  shows a luminaire  60  that utilizes an optical array  20  to emit a rectangular pattern of light  62  on the ground. It may become desired, however, to rotate the emitted light pattern  62  by 90 degrees without reconfiguring or moving the luminaire  60  or the light source. That is, making the emitted light pattern longer in the direction in front of and away from the luminaire  60  as opposed to longer in the direction on either side of luminaire  60 , as shown in  FIG. 13 . Movement and rotation of the optical array  20  by 90 degrees would rotate light pattern  62  by 90 degrees. 
         [0038]    For the various exemplary embodiments shown, the lenses  24  of the optical array  20  are all identical, that is, they each direct light in precisely the same manner. In alternative embodiments, there are no limitations on the similarity or difference between the individual lenses  24 . Every individual lens  24  on a given optical array  20  can have a different shape and direct light in a different pattern or direction, and every lens  24  can be identically shaped, or any combination thereof, where some lenses  24  are the same and other lenses  24  are different. Furthermore, the optical array  20  itself is not limited to any particular shape, including round, oval, rectangular, polygonal, etc. As long as one or more lenses  24  align with corresponding one or more LEDs when the optical array is rotated the desired amount, the shape of the optical array is not limited. 
         [0039]    According to the embodiments shown, optical array  20  is formed as a substantially square device which can be rotated easily in 90 degree increments to provide 4 independent light distributions from an array of LEDs  18 . It is noted, however, that other configurations of the optical array and sizes of the array are also contemplated. 
         [0040]    For example, an octagonal optical arrray, i.e., having eight sides, can be provided where instead of 90 degree increments, the optical device can be rotated in 45 degree increments to provide eight different light pattern formations without the need to move the luminaire or adjust the light source. It is known that LED luminaire design and manufacturing often requires intense thermal management design where thermal grease and other conductive materials and devices are carefully designed and placed within the luminaire to ensure proper heat dissipation. It is, thus, undesirable to disconnect or even adjust various heat conducting components after the luminaire is built and installed. By merely rotating the optical array  20 , in accordance with embodiments of the present invention, the light distribution can be adjusted without interfering with the thermal management system in place. 
         [0041]    Additionally, various numbers of LEDs  18  can be used. For example, any equal number of rows and columns can be used, such as, 3×3, as discussed above, 4×4, 5×5, etc. The arrangement of LEDs  18  should allow for the rotation of the optical array  20  to permit each respective lens  24  to mate with a corresponding LED  18 . 
         [0042]      FIGS. 14-17  depict another exemplary optical array  80  that includes a body  82  having a plurality of openings  84 . Separate lenses  86  and plugs  88  can be installed in the array  80  as needed. According to this embodiment, any number of independent lenses  86  can be incorporated into the optical array  80  to generate a desired light pattern. The lenses can have any type of size, shape, and configuration to create a desired light output. The plugs  88  are connected to openings that would not include a lens  86 . A best shown in  FIG. 17 , the bottom of the base includes a ridge  90  for receiving a gasket  92 .  FIG. 17  also shows an alternative type of spherical lens  94  that can be used in various exemplary embodiments. The lenses  86 ,  94  and plugs  88  can be connected to the base  82  by any suitable manner, for example sonic welding. 
         [0043]    In an exemplary embodiment, the base  82  and the plugs  86  are substantially opaque, allowing the light emitted from the LEDs  18  to be focused solely by the lenses  86 . Different types of lenses can be used and in different patterns and orientations to provide a desired light output. This versatility can provide an advantage over a single-piece optical array and lens assembly, which require a separate molded part to create certain light out puts as opposed to a single base  82  that can be used with different lenses  86 . 
         [0044]    As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the exemplary embodiments of the present invention, and are not intended to limit the structure of the exemplary embodiments of the present invention to any particular position or orientation. Terms of degree, such as “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of the given value, for example, general tolerances associated with manufacturing, assembly, and use of the described embodiments.