Abstract:
A method and apparatus is provided that enables the rotational adjustment of a non rotationally-symmetrical optical element in order to change the direction of the emitted light from an LED emitter of a lighting unit or to change the overall luminous distribution pattern in a luminaire including a plurality of LED emitters and optical elements. The apparatus enables simple and accurate rotational adjustment, while providing for the retaining of the selected rotational position of the optical element. The adjustment can be made before or after the installation of the lighting unit or luminaire, and can be accomplished without requiring tools and expert personnel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application represents a National Stage application of PCT/US2014/014147 entitled “Method and Apparatus for Rotational Adjustment of Optics” filed Jan. 31, 2014 which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/759,019 entitled “Method and Apparatus for Rotational Adjustment of Optics” filed Jan. 31, 2013. The entire content of this application is  incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention is related generally to the field of lighting, and in particular to the rotational adjustment of non rotationally-symmetrical optical elements in LED emitter lamped luminaires. 
     Asymmetrical or otherwise non rotationally-symmetrical light distribution is a frequently utilized feature in LED luminaires, such as in luminaires for the lighting of highways, roadways and walkways, parking garage luminaires, gas station luminaires, certain floodlights, downlights, aisle lighters in supermarkets and warehouses, tunnel lights, and the like. Particular distribution patterns are typically produced by dedicated optical elements, or made adjustable through various mechanical features of the luminaire, which typically involve the tilting and/or rotating of the LED emitter together with the optical element. Incorporation of these types of adjustable features may impact on various luminaire functions, including the thermal management of the luminaire. Adjustment of the features typically requires tools. 
     In certain applications, the rotational adjustment of non rotationally-symmetrical optics might be a viable method for modifying the luminaire&#39;s default luminous distribution pattern. Rotational adjustability of non rotationally-symmetrical optics can simplify luminaire design, and can significantly broaden luminaire functionality. Simple, tool-less adjustability provides practical and economic benefits, and adjustment-aiding graphic features provide for accuracy. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide for adjustability of the luminous distribution pattern of luminaires and thereby enabling post manufacturing, and post-installation change of the luminous distribution pattern in accordance with a broad variety of needs. 
     Another object of this invention is to provide a simple method of adjustability that in some cases does not require expert personnel. 
     Another object of this invention is to provide a rotatably adjustable apparatus, which can be adjusted without tools. 
     Another object if this invention is to provide for accuracy of the adjustment by incorporating adjustment aiding graphic features. 
     It is another object of this invention to provide an apparatus that retains the optical element in the adjusted position by mechanical means, and maintains the desired setting under expected operating conditions. 
     Further object of this invention is to enable manufacturers to simplify luminaire design, and achieve different light distribution patterns with fewer components which are adjustable, instead of utilizing a plurality of dedicated, non-adjustable components. 
     These and other objects of the invention are achieved by providing an optical element, either in a lighting unit having a single optical element or a luminaire including multiple optical elements, which can be selectively, rotationally adjusted, without the need for tools, in order to alter the direction of the light for the lighting unit or alter the light distribution or dispersion pattern associated with the luminaire in a convenient manner. More specifically, a method and apparatus are provided that enables the rotational adjustment of a non rotationally-symmetrical optical element in order to change the direction of the emitted light from an LED emitter of a lighting unit or to change the overall luminous distribution pattern in luminaires having a plurality of LED emitters and optical elements. The invention enables simple and accurate rotational adjustment, while providing for the retaining of the selected rotational position of the optical element. The adjustment can be made before or after the installation, and can be accomplished without requiring tools and expert personnel. 
     Additional features and advantages of the invention will become more readily apparent from the following detailed description of the invention with reference to the accompanying drawings wherein like reference numerals refer to corresponding parts in the several views. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view illustration of the optical element and the apparatus that provides for the rotational adjustment of the optical element in a preferred embodiment. 
         FIG. 2  is a cross-sectional view of a schematic representation of the optical element and the apparatus that provides for the rotational adjustment of the optical element. 
         FIG. 3  is a partial plan view illustration of the mechanical engagement between a spring projection of the wreath and a recess on the gear feature of the bezel. 
         FIGS. 4A-4D  illustrate different potential positions for rotationally adjustable optical elements to establish different dispersion patterns for a luminaire in accordance with the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For the purposes of this invention, “LED emitter” is a COB (chip-on-board) type LED module, a single SMD (surface mounted device) type LED, or an array comprising a plurality thereof, and the like. In addition, as used herein, “optical element” is a non rotationally-symmetrical or asymmetrical optic that is a spun, stamped, or fabricated metal reflector, an injection molded plastic reflector, a TIR (Total Internal Reflection) type optic, glass or plastic lens type optic, a Fresnel lens type optic, a light shaping diffuser, an otherwise symmetrical optic or light filter with non rotationally-symmetrical color features, and the like. 
     This invention is concerned with the luminaire-integration and functionality of non rotationally-symmetrical optical elements, in that it provides for rotational adjustment of the optical elements. The rotatable mode of the rotational adjustment can be multi-click type in predetermined intervals, or smooth, without pre-determined intervals. 
     With initial reference to  FIGS. 1 and 2 , there is shown a lighting unit  10  including an LED emitter  12  configured to be rigidly attached to a luminaire housing or to a heat-sink (not shown in these figures). In the embodiment shown, lighting unit  10  also includes a ring  14  having a zero-position indicating feature  16 , a separate wreath  18 , a bezel  20 , a position indicating dial  22  and a non rotationally-symmetrical optical element  24 . At this point, it should be noted that each of ring  14 , wreath  18  and bezel  20  can be made of various suitable materials including, but not limited to, metal or plastic material. More importantly, as will be detailed fully below, the invention allows for rotational adjustment of non rotationally-symmetrical or asymmetric optical element  24 . 
     In the preferred embodiment shown in these figures, optical element  24  is rigidly attached to bezel  20 . On the other hand, bezel  20  is mounted for rotation relative to ring  14 , which is rigidly attached directly to a luminaire housing or to a heat-sink, or indirectly attached to the housing or heat-sink through attachment features that may be provided on an LED emitter, or on a luminaire-integrating interface of the LED emitter or emitter module. In any case, the ring  14  and bezel  20  are concentrically positioned around a central axis, which is centered on and perpendicular to the light emitting surface of the LED emitter  12 . Therefore, the axis of rotation of bezel  20  is also the axis of the emitting surface of LED emitter  12 . Most preferably, rotatable adjustment of bezel  20  facilitates angular, i.e., up to 360 degree rotational, adjustment of optical element  24  relative to the permanently stationary position of LED emitter  12  and ring  14 . 
     In the preferred embodiment of this invention, lighting unit  10  also incorporates mechanical features and components which allow for rotatable, elastic engagement between adjustable bezel  20  and the rigidly attached ring  14  in predetermined, rotation-angular intervals. In a preferred embodiment shown in  FIG. 3 , the ring-facing side of bezel  20  includes an inward-facing gear feature of recesses and projections (not separately labeled) at predetermined regular angular intervals. The gear feature is concentric with bezel  20  and is preferably an integral feature of bezel  20 , i.e., is formed as part of bezel  20 . 
     Wreath  18  is rigidly attached to the bezel-facing side of ring  14  and includes an outward-cantilevered spring projection (sprung tooth or pawl), or preferably a plurality thereof as illustrated in  FIG. 3  but not separately labeled. The spring projection, or the plurality thereof, function to elastically bend in the direction of the rotation when engaged by the projections of the inward-facing gear feature of the rotating bezel  20 . When released, the spring projections elastically extend into the recesses of the gear feature, thereby retaining the position of bezel  20 . In this sense, a detent mechanism is provided to enable various rotational positions to be established for bezel  20  and to retain bezel  20  in any select one of these rotational positions such that, under expected operating conditions, the selected rotational position of bezel  20  is maintained until a further deliberate adjustment is made. Actually, the rotatable adjustment of bezel  20  can be of the ratchet-type such that bezel  20  can be rotated uni-directionally for adjustment purposes, or bi-directional rotation can be provided to allow both clockwise and counter-clockwise adjustment. 
     In the embodiment shown, repeated elastic engagement between the spring projections of wreath  18  and the position retaining recesses of the gear feature of bezel  20  preferably imparts a click-type feedback upon the adjusting person. The click-type feedback is both audible and tactile. The number of projections and recesses of the gear feature determines the degree of the intervals in which bezel  20  engages wreath  18  and ring  14 . For example, a circular division into sixty projections and recesses establishes adjustability in six degree intervals, while a division into thirty projections and recesses establishes adjustability in twelve degree intervals. While the above describes particular constructions and methods for achieving elastic engagement, it is to be understood that alternative arrangements and methods that yield elastic engagement can also be employed and are included within the scope of the present invention, with the alternative structure and methods resulting in similar, intervallic adjustment, or smooth adjustment without predetermined intervals. 
     In the depicted embodiment, position indicating dial  22  is rigidly attached to the visible face of bezel  20 . The dial  22  comprises graphic markings that display apparatus specific, intervallic rotation-angular divisions, starting with a clearly indicated zero degree marking. In addition, ring  14  includes the zero-position indicating feature  16 , which can be rigidly attached to ring  14  or constituted by a contiguous part thereof. In simplest form, the zero-position indicating feature  16  comprises a single graphic marking that clearly denotes the zero-position. In the zero-position setting, a zero degree marking of dial  22  lines up with the graphic marking on the zero-position indicating feature  16  of ring  14 . 
     The zero-position of optical element  24  in lighting unit  10  is determined by the overall design, with the manufacturer installing optical element  24  in bezel  20 , and the overall assembly in the lighting unit  10  in accordance with the design. Therefore, the zero-position setting of optical element  24  is the default position for the lighting unit  10 , with this positioning being adjustable on an as-needed basis, prior to, and/or following installation in accordance with the invention. When rotating bezel  20 , dial  22  also rotates, and the position of the graphic markings thereof relative to the marking on the zero-position indicating feature  16  of ring  14  provides a simple graphic indication of the degree of rotational departure from the default zero-position. 
     With the above construction, optical element  24  can be rotatably adjusted, particularly manually without the need for tools, to conveniently alter the direction of the light emitted from lighting unit  10 . In addition, a luminaire can be constructed to incorporate a plurality of lighting units  10 , with one or a plurality of optical elements  24  being individually rotatably adjusted to alter the overall light dispersion or distribution pattern of the luminaire. To further emphasize this aspect of the invention,  FIGS. 4A-4D  illustrate a luminaire  30  including a housing  35  supported a pair of adjacent or side-by-side, adjustable optical elements  24 A and  24 B. Here, housing  35  is shown to be ceiling mounted and the illustrated light patterns are established on a floor beneath luminaire  30 . As can be seen, one or more of optical elements  24 A and  24 B can be adjusted to alter the overall light dispersion pattern for the luminaire  30 . More specifically, by way of example,  FIG. 4A  illustrates the default position for both optical elements  24 A and  24 B, wherein asymmetric optical element  24 A has a 60 degree beam spread, providing a 15 degree (from the vertical) light throw on the left or shortened side as viewed in this figure and a 45 degree (from the vertical) light throw on the right or elongated side. On the other hand, optical element  24 B presents basically a mirror image, thereby having a 45 degree left side throw and a 15 degree right side throw, both relative to vertical, to establish a certain light pattern  50 A, such as on a floor beneath luminaire  30 .  FIG. 4B  has optical elements  24 A and  24 B rotated by 180 degrees relative to the default position such that the inner light throws are at 15 degrees and the outer throws are at 45 degrees relative to vertical, thereby creating a different light pattern  50 B.  FIG. 4C  has optical element  24 A in the default position and optical element  24 B rotated by 180 degrees to establish a light pattern  50 C which is essentially elongated in one direction.  FIG. 4D  has both optical elements  24 A and  24 B rotated 90 degrees counterclockwise from the default position to establish pattern  50 D. In any case, it should be readily apparent from these exemplary arrangements that, by adjusting the aim of one or more of the asymmetrical optical elements  24 A and  24 B, different light dispersion or distribution patterns can be readily achieved. Of course, in accordance with the invention, the optical elements  24 A and  24 B are maintained in these established positions until repositioning is desired, with either an incremental or smooth adjustment being available and the adjustments can result in a broad variety of light distribution patterns for luminaire  30 . 
     Based on the above, it should be readily apparent that the principles of the invention have been shown and described herein in connection with specific embodiments, but it is to be understood that such embodiments are by way of example, and are not limiting. For instance, although the drawings do not illustrate fasteners, or indicate the means of fastening, it is to be understood that the LED emitter is typically rigidly attached to the luminaire housing or a heat-sink. In embodiments where optics are dedicated to the apparatus described herein, the bezel can be a contiguous part of the optical element, and can be formed together with the optical element. This can be a highly advantageous feature in case the optical element is made of plastic material, and is injection molded. In addition, the position-indicating graphics might also be an integral feature of the bezel-comprising optical element, or can be provided as a separate dial. Furthermore, although examples are set forth with a luminaire including a pair of optical elements, it should be understood that there would typically be more than two optical elements in a given luminaire, with one or more of these optical elements being adjustable through the various features of the lighting unit. The various optical elements can assume various configurations. For instance, the various optical elements can be lined up along a straight line, extend along two or more parallel lines, provided around the circumference of a circle, arranged at points of a polygon, or positioned in many other arrangements. In particular, a single luminaire with a plurality of the lighting units, for example ranging from six to ten, can be adjusted to selectively create a wide range of distribution patterns commonly employed in various fields, such as outdoor lighting distribution patterns I-V as established by the IESNA (Illuminating Engineering Society of North America). Regardless, the invention provides for one or more optical elements of a luminaire to be asymmetrical and rotationally adjustable, specifically manually, in a simple and accurate manner, without the need for tools.