Sporting field illuminating lighting fixtures having improved light distribution

Information

  • Patent Grant
  • 6190023
  • Patent Number
    6,190,023
  • Date Filed
    Monday, April 7, 1997
    27 years ago
  • Date Issued
    Tuesday, February 20, 2001
    23 years ago
Abstract
Luminaires intended to deliver maximal light flux to a playing field with improved uniformity, the invention provides primary reflector structures having shaped facets, the several reflectors being capable of maximizing lumen delivery onto the playing field when considered relative to economy of manufacture. In certain embodiments of the invention, a shielding device or flux manager is employed for producing target extinctions by management of flux to precisely pass flux nearby original arc and through a second bounce off the reflector structure to direct that flux back into the beam. A virtual arc is thus produced in proximity to the original arc with the virtual arc acting as a second source. The flux manager acts to reduce glare and “spill” light. Performance optimization is further provided in embodiments using the flux manager through additional use of a multi-faceted reflector insert which re-aims light which would have been incident on portions of the reflector structure and which light is blocked by the flux manager. The improved light distribution provided by the luminaires of the invention allow use of fewer luminaires for a given playing field lighting performance.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The invention relates generally to the lighting of stadia, playing fields and similar areas and particularly to lighting fixtures intended for such lighting applications and which utilize reflective surfaces in combination with illumination sources to produce desired work plane illumination levels.




2. Description of the Prior Art




The field of sports lighting has evolved over time into a form of outdoor lighting having characteristics similar to outdoor area lighting yet peculiar to those requirements which come into play when lighting athletic playing fields. Uniformity of illuminance is of critical importance as is illumination level per se with these factors being joined by the everpresent need for optimum performance at the lowest possible cost. Advances in the art thus occur at least in part through development of luminaire configurations which effectively deliver a maximal amount of flux onto a playing area. In the sports light field in particular both vertical and horizontal illuminances must also be addressed as must illumination levels required for optimum video camera operation inter alia. Luminaire design also typically takes into account conventional arrangements of pole locations, mounting heights and aiming angles. Other objectives include consistent overlap of beam patterns in order to maximize system performance while minimizing costly applications engineering efforts usually associated with sports lighting systems. The prior art has long encompassed the mounting of discrete clusters of sportslighting luminaires at periodic locations about the perimeter of a playing area. Within these conventional system constraints, luminaire performance is evaluated not only as a single unit but also within these discrete clusters, the net distribution of each cluster being necessarily considered in performance evaluation. As is therefore to be appreciated, luminaire design in the sportslighting field is a complex matter dependent upon a variety of factors not the least of which is total system cost.




When considering cost, operational costs cannot be dismissed as inconsequential. Prior sportslighting systems which utilize less efficient light sources such as incandescent and mercury vapor must be improved in order to gain the benefits of greater efficiency with comparable light levels and desirable light quality which are to be gained from sources such as high pressure sodium and metal halide, as example Greatest luminaire flexibility is attained through luminaire design capable of using the widest variety of illumination sources to include high pressure sodium and metal halide and the like.




Examples of prior art lighting designed for the purposes to which the present invention are directed are disclosed by Lemons et al in U.S. Pat. Nos. 4,864,476 and 5,313,379 and by Tickner in U.S. Pat. Nos. 5,355,290 and 5,377,086. As is conventional in the art, these patents disclose the use of reflector structures intended to provide desired illumination levels on a work plane. Sportslighting luminaires of the prior art can also be seen in the TV Sportslighting luminaire manufactured by Lithonia Lighting, a division of National Service Industries, Inc. of Atlanta, Ga., this luminaire including in its optical structure an anodized aluminum reflector capable of a range of beam spreads. The TV luminaire further includes a horizontal degree aiming scale and repositioning locator as well as a vertical aiming adjustment mechanism complete with degree aiming scale and a repositioning stop. While sportslighting luminaire devices such as the TV luminaire of Lithonia Lighting provide lighting capabilities of substantial utility and while other luminaire devices of the prior art also provide capabilities desirably useful in the sportslighting field, a need exists in the art for sportslighting luminaires capable of improved cost and energy efficiencies and which particularly provide performance capabilities allowing use of fewer luminaires within a given system arrangement.




SUMMARY OF THE INVENTION




The invention provides luminaire structures intended for illumination of stadia, playing fields and similar areas and which are particularly adapted to mounting in discrete clusters on poles or the like at locations about the perimeter of a playing area which is to be illuminated. The luminaire structures of the invention are particularly improved in the several embodiments of the invention by reflectors which usually include a faceted reflector body with individual facets being arranged in a manner intended to optimize performance. In the several embodiments of the invention, improved principal reflectors are used in combination with an illumination source to provide an improved luminaire useful in sportslighting applications. In certain embodiments of the invention, faceted reflectors are combined according to the invention with a shielding device or flux manager and a reflector insert for optimization of light uniformity and reduction of glare and “spill” light. The flux manager structures of the invention produce target extinctions by management of flux to precisely pass flux nearby original arc and through a second bounce off of the principal reflector to direct that flux back into the beam. A virtual arc is produced in proximity to the original arc with the virtual arc acting as a second source. The reflector insert is a multi-faceted reflector with aimed facets which re-direct light which would have been incident on the flux manager. One embodiment of the invention is comprised of a principal reflector having individual facets aimed in a manner to optimize uniformity of light distribution with reduced glare and light “spill” without the need for a flux manager and reflector insert. The several embodiments of the invention provide improved light distributions and performance of a magnitude which allows use of fewer luminaires for a given playing field configuration.




The luminaire structures of the invention typically include a ballast and junction box housing assembly having mounting trunnion arrangements with a horizontal degree aiming scale and a respositioning locator. Vertical aiming adjustment is also provided to include a degree aiming scale and a repositioning stop. Mounted to the housing assembly is one of the primary reflectors of the invention, the reflectors being sealed by a hinged lens formed of heavy-duty thermal-resistant, shock-resistant and impact-resistant tempered glass. An illumination source such as a standard BT-56 jacketed lamp is mounted within the principal reflector by a porcelain mogul-base socket in a fixed relation to the reflective surfaces of the principal reflector. The luminaire structures of the invention typically utilize high pressure sodium or metal halide lamps of wattages within the range of 400 watts to 1500 watts. A range of beam spreads are provided by the luminaire structures of the invention.




Accordingly, it is an object of the invention to provide luminaire structures capable of efficiently illuminating stadia, playing fields and similar areas with light of improved uniformity.




It is another object of the invention to provide luminaire structures intended for sportslighting applications and having improved principal reflectors formed with facets intended to optimize performance, the principal reflectors being useful with conventional illumination sources and being improved in certain embodiments to reduce light “spillage” by the addition of a flux manager intended to produce desired target extinctions, the flux manager creating precise redirection of flux around original arc with the redirected flux being reflected by the principal reflector into the beam, the principal reflectors used with a flux manager further being optimized by addition of a reflector insert having aimed facets which re-direct light blocked by the flux manager.




It is a further object of the invention to provide luminaire structures having improved principal reflectors and/or improved reflector assemblies capable of sufficient improvement of illumination on the work plane of a playing field to allow use of fewer luminaires for a given playing field configuration.




Other objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a perspective view of a first embodiment of a luminaire apparatus of the invention, and having a principal reflector configured with annular facets, a flux manager and a reflector insert;





FIG. 2

is a side elevational view of the luminaire apparatus of

FIG. 1

;





FIG. 3

is a plan view of the luminaire apparatus of

FIG. 1

;





FIG. 4

is an exploded view in perspective of the principal reflector of

FIG. 1

configured as a portion of a reflector assembly forming a portion of a luminaire apparatus having a flux manager and a reflector insert disposed within sealed optics of said luminaire apparatus;





FIG. 5A

is a side elevational view in section of one-half of the principal reflector of

FIGS. 1 through 4

;





FIG. 5B

is a front elevational view of the principal reflector of

FIG. 5A

;





FIG. 5C

is a detail view in section of a rim portion of the principal reflector of

FIGS. 5A and 5B

;





FIGS. 6A through 6E

are elevational views of a shielding device or flux manager useful according to the invention;





FIGS. 7A through 7C

are elevational views of a reflector insert useful according to the invention;





FIG. 8

is a diagram illustrating the geometrical configuration of a flux manager conformed according to the invention;





FIG. 9

is a diagram illustrating the geometrical configuration of an involute;





FIG. 10

is a perspective view of a principal reflector of the invention having annular facets in the manner of

FIGS. 5A and 5B

and having a lens mounted thereto;





FIG. 11

is a side elevational view of an embodiment of the invention using the principal reflector assembly of

FIG. 10

on the optical structure of the luminaire as shown;





FIG. 12

is a plan view of the luminaire of

FIG. 11

;





FIG. 13

is a front elevational view of a principal reflector of the invention having multiple regularly-arranged facets;





FIG. 14

is a perspective view of the principal reflector of

FIG. 13

;





FIG. 15

is a front elevation view of a multi-faceted principal reflector of the invention having all facets thereof aimed to create a desired light distribution;





FIG. 16

is a perspective view of the principal reflector of

FIG. 15

;





FIG. 17A

is a diagram illustrating lune segments of the principal reflector of

FIG. 15

;





FIG. 17B

is a diagram of the numbered lune segments forming the reflector of

FIGS. 15 and 16

;





FIGS. 18A through 18U

are diagrams illustrating respectively lines


1


through


21


of the reflector of

FIGS. 15 and 16

;





FIG. 19A

is a diagram illustrating the ideal vertical candela trace of the principal reflectors of the invention;





FIG. 19B

is a diagram illustrating the ideal horizontal candela trace of the principal reflectors of the invention, and;





FIG. 20

is a schematic illustrating an ideal illuminance distribution such as is intended to be produced according to the invention.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




Referring now to the drawings and particularly to

FIGS. 1 through 4

, a luminaire assembly


10


configured according to a preferred embodiment of the invention is seen to include a substantially weatherproof housing


12


formed of a ballast box


14


and a junction box


16


, the luminaire assembly


10


further including a reflector assembly


18


sealed by means of glass lens


20


mounted to the substantially circular periphery of principal reflector


22


. The reflector assembly


18


is sealed to prevent entrance of contaminants into an optical chamber


24


defined by the reflector


22


. Since the luminaire assembly


10


is intended for outdoor use, it is necessary to seal the reflector assembly


18


by means of the glass lens


20


in a manner which will be described in detail hereinafter. Similarly, in order to house electronics (not shown) including ballast (not shown) and the like within the housing


12


, the ballast box


14


and the junction box


16


must seal together in a weatherproof manner and the housing


12


generally must be weatherproof. It is to be understood, however, that the luminaire assembly


12


can be used indoors such as in indoor stadia or the like. Even in an indoor environment, the luminaire assembly


10


is intended to retain weatherproof capabilities in order to positively seal electronics and the like within the housing


12


and to further seal the optical chamber


24


of the reflector assembly


18


in order to prevent degradation of the functioning of electronics within the housing


12


or degradation of the optical operation of the reflector assembly


18


which can be caused by miscellaneous contaminants including water and the like. Accordingly, even though the luminaire assembly


10


may be referred to herein as being an “outdoor” luminaire, it is to be understood that the luminaire assembly


10


can function in both indoor and outdoor environments.




The principal reflector


22


is formed of a heavy-gauge anodized aluminum material, inner wall surfaces of the reflector


22


primarily defining the optical chamber


24


sealed by means of the glass lens


20


. The reflector


22


, which is also seen in

FIGS. 5A through 5C

, has a thickness sufficient to provide the strength and rigidity necessary for functioning of the reflector


22


as the housing for the optical chamber


24


including mounting of the glass lens


20


about the periphery thereof and the supporting of structure including lamping which must be carried by the reflector


22


. Further, the reflector


22


must be sufficiently rugged to withstand winds and the like in a use enviroment. It should be understood that the light reflective inner wall surfaces of the reflector


22


could be formed on a backing of other material with that backing (not shown) being sufficiently rigid and having sufficient strength to accomplish the intended purpose. The housing


12


is preferably formed of die-cast aluminum, the electrical components (not shown) contained within the housing


12


being thermally isolated from the reflector


22


and the interior of the optical chamber


24


as well as thermally isolated from socketry and lamping which will be described hereinafter.




Lamping preferably takes the form of a standard BT56 jacketed metal halide lamp for wattages of 1000 and 1500 watts, an ED37 being usable for 400W. A 750 watt high pressure sodium lamp may also be employed. The lamp is referred to herein as lamp


40


but can take several forms and wattages such as are conventionally manufactured by OSRAM, Phillips, General Electric and Venture inter alia. The lamp


40


is mounted transversely within the optical chamber


24


as will be described hereinafter, the transverse orientation of the lamp


40


creating a small extinction angle when spill light control is desired. This orientation of the lamp


40


maximizes the average tilt factor through typical aiming angles.




The luminaire assembly


10


is further seen to include a trunnion


26


which mounts the housing


12


for pivotal movement necessary for aiming of the luminaire assembly


10


, the trunnion


26


further being seen to mount to a bracket


28


for mounting to cooperating structure (not shown) on a pole (not shown) or other structure intended for mounting of the luminaire assembly


10


in an elevated position about the periphery of an athletic field or the like. Although not shown in the drawings, a horizontal aiming scale is typically provided between the trunnion


26


and the bracket


28


to facilitate aiming of the luminaire assembly


10


. Further, a vertical aiming scale


30


is seen to be located at the connection of the housing


12


and the trunnion


26


for aiming of the luminaire assembly


10


. A socket arm


32


connects to and extends from the junction box


16


of the housing


12


to mount a socket bracket


34


which in turn mounts mogul socket


36


, the socket


36


extending through opening


38


into the interior of the reflector assembly


18


to mount the lamp


40


. Edge surfaces of the socket arm


32


which contact exterior surfaces of the reflector assembly


18


are flanged (not seen in the drawings) and shaped to conform to outer surfaces of the reflector


22


. The socket arm


32


also covers the opening


38


and effectively provides a sealing function with an appropriate gasket (not shown) in the area of the aforesaid flanged portions of the socket arm


32


. The socket arm


32


is essentially hollow interiorly and houses electrical connectors, wiring and the like (not shown) which connect to the socket


36


from the interior of the junction box


16


through the socket arm


32


. Reinforcing strips


39


disposed on inner wall surfaces of the reflector


22


facilitate mounting of the socket arm


32


to the reflector


22


through use of screws


41


. The socket arm


32


thus mounts the lamp


40


with the lamp


40


being disposed in a fixed location transversely within the optical chamber


24


in a predetermined relationship to the reflector


22


and to other portions of the reflector assembly


18


which will be described in detail hereinafter.




While the luminaire assembly


10


includes other functional elements of structure particularly including structure associated with and/or contained within the housing


12


, the primary advance in the art afforded by the invention relates to the reflector assembly


18


and thus those remaining portions of structure not described or shown involving the housing


12


including details of the boxes


14


,


16


and components associated therewith or contained therein will not be described further herein. It is to be understood that ballast devices (not shown) suitable for operation of the luminaire assembly


12


are known in the art and are devised to be housed by the ballast box


14


, for example, and structure such as gaskets (not shown) necessary for sealing of the ballast box


14


to the junction box


16


, for example, are also seen to be conventional in the art.




Considering now with continuing reference to

FIGS. 1 through 4

and with additional reference to

FIGS. 5A through 5C

, the reflector assembly


18


is also seen to include a shielding device known herein as a flux manager


42


which is mounted within the optical chamber


24


by means of brackets


44


and


46


respectively substantially at the periphery of the reflector


22


defined by reflector rim


48


. A detailed view of the reflector rim


48


is seen in

FIG. 5C

, the rim


48


including an annular trough


50


defined distally by annular flange


52


having an outwardly turned-up annular edge


54


. The glass lens


20


is mounted to the reflector rim


48


by means of a lens ring


56


which is substantially circular in conformation and which is split at one location thereof with riveted screw brackets


58


being located at the free ends of the ring


56


for receipt of a screw


60


which is tightened by torque nut


62


in a conventional manner to mount the glass lens


20


. The lens ring


56


is formed either of galvanized material or stainless steel. A lens gasket


64


is disposed about the periphery of the lens


20


and held thereon by the lens ring


56


, also in a conventional manner. The lens ring


56


can be provided with spaced slots


65


which receive a portion of a lens ring latch clip


66


, the latch clips


66


being regularly disposed about the lens ring


56


as is also conventional in the art. A hinge bracket


68


mounts to the exterior of the reflector assembly


18


by means of a rivet


70


and washer


72


, a portion of the hinge bracket


68


fitting between and aligning with portions of the brackets


58


disposed on the lens ring


56


to receive the screw


60


to provide a positive mounting of the lens


20


to the reflector


22


.




Centrally of the body of the reflector


22


, a flat


74


is formed, the flat having an aperture


76


formed therein for receiving a fastener such as a screw which in combination with fastening structure (not shown) attaches the reflector assembly


18


to the housing


12


. Interiorly of the optical chamber


24


and bounding the flat


74


, a semi-circular plate-like flat


78


having apertures


80


formed therein mounts a reflector insert


82


by means of pop rivets


84


which are received within aligned apertures


86


formed in the reflector insert


82


and further into the apertures


80


of the flat


78


. The reflector insert


82


is mounted in spaced relation to the flat


78


and to inner wall surfaces of the reflector


22


.




The flux manager


42


is mounted above a horizontal center line of the reflector


22


by the brackets


44


and


46


referred to hereinabove. The bracket


44


is substantially semi-circular in conformation and mounts immediately inside of the lens


20


, the bracket


44


having apertures


88


formed one each at each end thereof, which apertures


88


align with apertures


90


formed at each end of the bracket


46


, pop rivets


92


being received through the aligned pairs of apertures


88


,


90


to mount the bracket


46


in a location extending substantially across the reflector


22


. The bracket


46


effectively lies along the horizontal diameter of the reflector


22


, the flux manager


42


being mounted by clips


94


which attach to the flux manager


42


and to the bracket


46


by means of pop rivets


96


. The bracket


46


is provided with a central plate


98


having apertures


100


formed near either end thereof to receive the pop rivets


96


for mounting of the flux manager


42


, the plate


98


having an arcuate cutout


102


extending over central portions thereof to conform to the shape of adjacent portions of the flux manager


42


.




Referring particularly to

FIGS. 4

,


5


A and


5


B, the reflector


22


is seen to be provided with annular facets


104


through


118


which are essentially concentric. The facets


104


through


118


are defined by segments of the reflector


22


identified as segments


120


through


134


, these segments defining the reflector


22


and essentially comprising frusto-conical sections joined at annular perimeters thereof to form the reflector


22


, each of the segments


120


through


134


essentially having a linear cross section as is seen in FIG.


5


A.

FIG. 5A

further provides relative dimensions of the segments


120


through


134


for a reflector


22


having a diameter of essentially


24


inches.

FIG. 5A

also shows the angle of each of the annular facets


104


through


118


relative to a reference line


136


, these angles being chosen for optimization of the total reflector output with respect to a desired light distribution. It is to be understood that the relative sizes of the facets


104


through


118


and the angles of the facets


104


through


118


relative to a reference could be produced by formation of a reflector body having outer surfaces which do not take the particular shapes of the segments


120


through


134


but could effectively comprise another shape within which the facets


104


through


118


are formed. However, for ease of manufacture, the segments


120


through


134


comprise exterior surfaces of the reflector


22


and are relatively defined by the vertical and horizontal dimensions in x and y planes as can be inferred from the measurements provided in FIG.


5


A. In order that the thickness of the material forming the reflector


22


does not alter the optical characteristics of the reflector


22


, the dimensions given are to the inside surfaces of the reflector


22


.




Given the optical characteristics of the reflector


22


as provided by the annular facets


104


through


118


, it is seen that a shielding device capable of producing a target extinction is desirable and can be provided by the flux manager


42


, the flux manager


42


blocking light which would otherwise leave the lamp


40


and produce glare or “spill”. In luminaire structures of the prior art, this light is either absorbed by a low reflectance surface or redirected by a diffusing surface. In the present invention, the flux manager


42


optimizes performance of the principal reflector


22


. The flux manager


42


is provided with an involute conformation which precisely redirects the light which is blocked as aforesaid and redirects that light past the original arc provided by the lamp


40


to form a second image, this flux then being reflected by the principal reflector


22


into the beam which is directed onto the surface which is to be illuminated. The shape of the flux manager


42


acts to define an extinction angle which begins blocking the arc at 6.25° above center beam and completely blocks the arc at 11°. In other words, the flux manager


42


produces a beam which begins extinguishing at just above 6° above the aiming angle and is totally extinguished at 11°. The flux manager


42


therefore acts as a shielding device which redirects light, which would otherwise be glare, into the beam, thus optimizing light directed onto a playing field or the like by the principal reflector


22


. The flux manager


42


essentially produces a virtual arc which is close to the original arc, the virtual arc acting due to the provision of the flux manager


42


as a second source.




The particular conformation of the flux manager


42


is seen in

FIGS. 6A through 6D

and which is more appreciated by reference to

FIGS. 8 and 9

. The flux manager


42


takes the shape of an involute having the following equation as derived in FIG.


9


:








x=a


cos ∅+


a


∅ sin ∅ and










y=a


sin ∅−


a


∅ cos ∅






as related to Cartesian coordinates where BP={circumflex over (BA)}. As seen in

FIG. 9

, “a” is taken to be the radius of arc tube


41


of the lamp


40


, the arc tube


41


being centered in the optical chamber


24


. Referring to

FIG. 8

, the shape of the flux manager


42


is derived in x, y and z with 0, 0, 0 being the center of the arc tube


41


of the lamp


40


with the center of a circular section being taken as a point on that circle forming the arc tube of the lamp at (0.1381,0.0920) with the radius being taken as (3.6504) for formation of a circular curve. For the dimensions required, an angle of 75.8361° from the y axis is subtended with an angle of 10.9082° being subtracted therefrom, the involute lying there-between. As might be generally described, the involute which is the flux manager


42


has an arcuate central body portion


138


which is partially defined by a lowermost edge


140


which is substantially a straight line and which is located just above the horizontal centerline of the reflector


22


. At either end of the central body portion


138


, the flux manager


42


curves outwardly in two directions to form end portions


142


which are nearly spherical sections. The edge


140


of the flux manager


42


curves outwardly to form arcuate edges


144


. In essence, the involute which is the flux manager


42


is symmetrical about a line bisecting the lower-most edge


140


and uppermost edge


146


. The uppermost edge


146


also is linear and curves near either end thereof to form arcuate edges


148


. The arcuate edges


144


and the arcuate edges


148


intersect at outermost ends of the flux manager


42


thus terminating the involute at either end of the flux manager


42


. The flux manager


42


is preferably generated as a surface of revolution constructed of an involute in the vertical dimension and an empirical line having an arc at either end in the horizontal direction.




In those embodiments of the invention which utilize the flux manager


42


, the reflector insert


82


is also utilized, the structure of the reflector insert


82


being best seen in

FIGS. 7A through 7C

. The reflector


82


is seen to be comprised of a multiplicity of facets


150


which re-aim light which would have been incident on portions of the reflective surface of the principal reflector


22


and which then would be blocked by the flux manager


42


. In essence, the reflector insert


82


causes the flux which would have been impingent on the flux manager


42


to be redirected to exit the optical chamber


24


at the highest possible angle below center beam without striking the flux manager or being incident with the arc of the lamp


40


. As an alternative, some light can pass over and some light can pass under. The reflector insert is symmetrical about a centerline except that five facets are removed from one side thereof for mechanical convenience. A principal reflector such as the reflector


22


fitted with the reflector insert


82


and having a diameter of nominally


24


inches would have a reflector insert


82


having a length of approximately


13


inches. The facets


150


are empirically sized and shaped to direct flux incident thereon as aforesaid.




The reflector assembly


18


seen in

FIGS. 1 through 4

utilizes the principal reflector


22


having the annular facets


104


-


118


as particularly shown in FIG.


5


A. The reflector assembly


18


of

FIGS. 1 through 4

is provided with the flux manager


42


and the reflector insert


82


to provide the functions described herein. However, the principal reflector


22


can be utilized as seen in

FIG. 10

without the addition thereto of the flux manager


42


and the reflector insert


82


. In essence, the principal reflector


22


can be sealed by means of the glass lens


20


and the lens ring


56


inter alia with the principal reflector


22


being mounted to a housing such as the housing


12


of

FIG. 1

inter alia, thereby providing a reflector assembly


160


. For ease of illustration, the reflector assembly


160


is shown without the complication of a housing such as the housing


12


of

FIG. 1

inter alia. The reflector assembly


160


provides a desirable distribution of light to a playing field or the like albeit with some loss of lamp lumen output to glare or “spill”.





FIGS. 11 and 12

illustrate a luminaire assembly


170


having lamp


176


mounted transversely within optical chamber


174


defined by principal reflector


176


and sealed by lens


178


as afore-said relative to the mounting of the lens


20


to the principal reflector


22


. The lamp


172


is seen to be mounted by socket


180


which is a porcelain mogul base socket having a copper alloy nickel plates screw shell and center contact (not shown), the socket


180


being listed for up to 1500 watts at 600 volts and rated for 5KV pulses. The socket


180


essentially takes the same form as the mogul socket


36


described herein relative to the luminaire assembly


10


. The luminaire assembly


170


is illustrated in order to not only show in a simplified illustration the mounting of the lamp


172


by means of the socket


180


carried by diecast aluminum socket arm


182


, but also to point out that the several principal reflectors described herein can be utilized in a luminaire assembly such as the luminaire assembly


170


which does not utilize a shielded device such as the flux manager


42


or an internal reflector such as the reflector insert


82


. In essence, the luminaire assembly


170


could take the form of the principal reflector


22


having the annular facets


104


-


118


or could take the form of principal reflector


190


of

FIGS. 13 and 14

or principal reflector


200


of

FIGS. 15 and 16

inter alia, the principal reflectors


190


and


200


being described hereinafter.




Referring now to

FIGS. 13 and 14

, the principal reflector


190


is seen to be formed with annular concentric arrays


192


of facets


194


, each array


192


corresponding to the similarly located segments


120


through


134


of FIG.


5


A. Each array


192


is broken down into the facets


194


of each array by virtue of forty radial lune segments


196


which extend from the geometric center of the principal reflector


190


to cause each of the annular concentric arrays


192


to comprise forty of the facets


194


. A differing number of the lune segments


196


could be employed, the number chosen being suitable for manufacturing convenience and reflector performance. As is readily appreciated from a consideration of

FIGS. 13 and 14

, the facets


194


on the outermost array


192


have a different area and configuration relative to the facets


194


on those arrays


192


located progressively inwardly of the principal reflector


190


. For simplicity of illustration, only the principal reflector


190


is shown in

FIGS. 13 and 14

. As aforesaid, the principal reflector


190


can be placed into the luminaire assembly


170


of

FIGS. 11 and 12

in order to form a luminaire assembly utilizing the principal reflector


190


. Similarly, the principal reflector


190


can substitute for the principal reflector


22


in the luminaire assembly


10


and thus be utilized in combination with the flux manager


42


and the reflector insert


82


. The facets


194


are each essentially planar.




Referring now to

FIGS. 15 and 16

, the principal reflector


200


is seen to be formed of a multiplicity of facets


222


which are of irregular configuration and formed as will be described hereinafter. Essentially, each facet


222


of the principal reflector


200


is aimed in order to provide a desired light distribution and performance. The aiming of each of the facets


222


obviates the need for the use of a shielding device such as the flux manager


42


described above and also obviates the need for the use of the reflector insert


82


as also described herein. The principal reflector


200


shown in

FIGS. 15 and 16

can substitute for the reflector of

FIGS. 11 and 12

to form a luminaire assembly as aforesaid. The facets


222


of the principal reflector


190


are defined by twenty-one lune segments identified as lune segments


201


,


202


. . .


221


as identified in

FIGS. 17A and 17B

. The lune segments


201


through


221


essentially having the conformation suggested in FIG.


17


A and being fully defined in

FIGS. 18A through 18U

which provide the shape of each of the twenty-one lune segments. The shape of each of the lune segments


201


through


221


is provided by definition of points as Cartesian coordinates in x and y as shown in

FIGS. 18A through 18U

, the points being connected to form the lune segments


201


through


221


and then cross-connected to define inner reflective surfaces, that is, the facets


222


of the principal reflector


200


for one-half of the inner reflective surfaces of said reflector


200


. The other half of the reflector


200


are formed according to the lune segments


201


through


221


on an opposite half of the reflector


200


across a vertical centerline. In essence, the inner reflective surfaces of the reflector


200


are mirror images across the vertical centerline.




As noted above,

FIGS. 18A through 18U

are diagrams illustrating the cross-sectional shapes of each of the lune segments


201


through


221


in x and y coordinates with x and y dimensions being provided by relative reference in the following Tables I through XXI which correspond respectively to lune segments


201


through


221


.












TABLE I











Lune segment 201














X




Y











11.328




0.000







9.641




2.717







9.107




2.782







7.691




4.573







7.394




4.547







6.159




5.784







5.977




5.728







4.873




6.602







4.758




6.538







3.751




7.161







3.665




7.086







2.728




7.521







2.681




7.459







1.796




7.751







1.776




7.709







0.919




7.883







0.914




7.859







0.070




7.929







0.000




7.931























TABLE II











Lune segment 202














X




Y











11.328




0.000







9.641




2.717







9.107




2.782







7.689




4.573







7.394




4.547







6.158




5.783







5.977




5.728







4.872




6.601







4.758




6.538







3.749




7.160







3.665




7.086







2.728




7.521







2.681




7.459







1.795




7.750







1.776




7.709







0.919




7.881







0.914




7.859







0.070




7.929







0.000




7.931























TABLE III











Lune segment 203














X




Y











11.328




0.000







9.635




2.717







9.107




2.782







7.684




4.573







7.394




4.547







6.157




5.783







5.977




5.728







4.872




6.601







4.758




6.538







3.747




7.157







3.665




7.086







2.727




7.519







2.681




7.459







1.795




7.749







1.776




7.709







0.919




7.881







0.914




7.859







0.070




7.929







0.000




7.931























TABLE IV











Lune segment 204














X




Y











11.328




0.000







9.725




2.706







9.107




2.782







7.742




4.578







7.394




4.547







6.189




5.793







5.977




5.728







4.894




6.613







4.758




6.538







3.760




7.169







3.665




7.086







2.733




7.527







2.681




7.459







1.797




7.754







1.776




7.709







0.920




7.884







0.914




7.859







0.070




7.929







0.000




7.931























TABLE V











Lune segment 205














X




Y











11.328




0.000







9.812




2.696







9.107




2.782







7.795




4.583







7.394




4.547







6.227




5.804







5.977




5.728







4.913




6.624







4.758




6.538







3.772




7.179







3.665




7.086







2.739




7.535







2.681




7.459







1.799




7.758







1.776




7.709







0.920




7.886







0.914




7.859







0.070




7.930







0.000




7.931























TABLE VI











Lune segment 206














X




Y











11.328




0.000







9.894




2.686







9.107




2.782







7.855




4.588







7.394




4.547







6.265




5.816







5.977




5.728







4.936




6.637







4.758




6.538







3.779




7.186







3.665




7.086







2.740




7.537







2.681




7.459







1.799




7.758







1.776




7.709







0.920




7.888







0.914




7.859







0.070




7.929







0.000




7.931























TABLE VII











Lune segment 207














X




Y











11.328




0.000







9.933




2.681







9.107




2.782







7.880




4.590







7.394




4.547







6.260




5.814







5.977




5.728







4.897




6.615







4.758




6.538







3.754




7.164







3.665




7.086







2.728




7.521







2.681




7.459







1.795




7.749







1.776




7.709







0.919




7.881







0.914




7.859







0.070




7.928







0.000




7.931























TABLE VIII











Lune segment 208














X




Y











11.328




0.000







9.378




2.749







9.107




2.782







7.543




4.560







7.394




4.547







6.076




5.758







5.977




5.728







4.819




6.572







4.758




6.538







3.721




7.135







3.665




7.086







2.713




7.501







2.681




7.459







1.788




7.734







1.776




7.709







0.917




7.873







0.914




7.859







0.070




7.925







0.000




7.931























TABLE IX











Lune segment 209














X




Y











11.328




0.000







9.368




2.750







9.107




2.782







7.506




4.557







7.394




4.547







6.068




5.756







5.977




5.728







4.819




6.572







4.758




6.538







3.720




7.134







3.665




7.086







2.713




7.501







2.681




7.459







1.787




7.733







1.776




7.709







0.917




7.873







0.914




7.859







0.070




7.923







0.000




7.931























TABLE X











Lune segment 210














X




Y











11.328




0.000







9.230




2.767







9.107




2.782







7.522




4.559







7.394




4.547







6.150




5.781







5.977




5.728







4.822




6.574







4.758




6.538







3.723




7.137







3.665




7.086







2.713




7.501







2.681




7.459







1.788




7.736







1.776




7.709







0.917




7.873







0.914




7.859







0.070




7.925







0.000




7.931























TABLE XI











Lune segment 211














X




Y











11.328




0.000







9.334




2.754







9.107




2.782







7.506




4.557







7.394




4.547







6.068




5.756







5.977




5.728







4.814




6.569







4.758




6.538







3.715




7.130







3.665




7.086







2.710




7.497







2.681




7.459







1.787




7.733







1.776




7.709







0.917




7.871







0.914




7.859







0.070




7.923







0.000




7.931























TABLE XII











Lune segment 212














X




Y











11.328




0.000







9.340




2.754







9.107




2.782







7.506




4.557







7.394




4.547







6.043




5.748







5.977




5.728







4.807




6.565







4.758




6.538







3.709




7.125







3.665




7.086







2.707




7.493







2.681




7.459







1.786




7.730







1.776




7.709







0.916




7.869







0.914




7.859







0.070




7.922







0.000




7.931























TABLE XIII











Lune segment 213














X




Y











11.328




0.000







9.339




2.754







9.107




2.782







7.516




4.558







7.394




4.547







6.043




5.748







5.977




5.728







4.807




6.565







4.758




6.538







3.713




7.128







3.665




7.086







2.707




7.493







2.681




7.459







1.787




7.732







1.776




7.709







0.916




7.869







0.914




7.859







0.070




7.922







0.000




7.931























TABLE XIV











Lune segment 214














X




Y











11.328




0.000







9.340




2.754







9.107




2.782







7.514




4.558







7.394




4.547







6.043




5.748







5.977




5.728







4.807




6.565







4.758




6.538







3.708




7.124







3.665




7.086







2.707




7.493







2.681




7.459







1.785




7.729







1.776




7.709







0.916




7.869







0.914




7.859







0.070




7.922







0.000




7.931























TABLE XV











Lune segment 215














X




Y











11.328




0.000







9.361




2.751







9.107




2.782







7.516




4.558







7.394




4.547







6.051




5.750







5.977




5.728







4.807




6.565







4.758




6.538







3.710




7.126







3.665




7.086







2.707




7.493







2.681




7.459







1.785




7.729







1.776




7.709







0.916




7.868







0.914




7.859







0.070




7.922







0.000




7.931























TABLE XVI











Lune Segment 216














X




Y











11.328




0.000







9.380




2.749







9.107




2.782







7.528




4.559







7.394




4.547







6.060




5.753







5.977




5.728







4.808




6.566







4.758




6.538







3.714




7.129







3.665




7.086







2.707




7.493







2.681




7.459







1.786




7.731







1.776




7.709







0.916




7.868







0.914




7.859







0.070




7.922







0.000




7.931























TABLE XVII











Lune Segment 217














X




Y











11.328




0.000







9.546




2.728







9.107




2.782







7.605




4.566







7.394




4.547







6.098




5.765







5.977




5.728







4.832




6.579







4.758




6.538







3.723




7.137







3.665




7.086







2.713




7.501







2.681




7.459







1.787




7.733







1.776




7.709







0.917




7.873







0.914




7.859







0.070




7.926







0.000




7.931























TABLE XVIII











Lune Segment 218














X




Y











11.328




0.000







9.983




2.675







9.107




2.782







7.891




4.591







7.394




4.547







6.249




5.811







5.977




5.728







4.899




6.616







4.758




6.538







3.755




7.165







3.665




7.086







2.727




7.520







2.681




7.459







1.794




7.747







1.776




7.709







0.918




7.878







0.914




7.859







0.070




7.927







0.000




7.931























TABLE XIX











Lune Segment 219














X




Y











11.328




0.000







9.993




2.673







9.107




2.782







7.914




4.593







7.394




4.547







6.298




5.826







5.977




5.728







4.944




6.641







4.758




6.538







3.779




7.186







3.665




7.086







2.739




7.536







2.681




7.459







1.798




7.757







1.776




7.709







0.920




7.884







0.914




7.859







0.070




7.929







0.000




7.931























TABLE XX











Lune Segment 220














X




Y











11.328




0.000







9.641




2.717







9.107




2.782







7.693




4.574







7.394




4.547







6.165




5.785







5.977




5.728







4.875




6.603







4.758




6.538







3.752




7.162







3.665




7.086







2.729




7.522







2.681




7.459







1.796




7.751







1.776




7.709







0.919




7.883







0.914




7.859







0.070




7.928







0.000




7.931























TABLE XXI











Lune Segment 221














X




Y











11.328




0.000







9.996




2.673







9.107




2.782







7.918




4.593







7.394




4.547







6.306




5.828







5.977




5.728







4.960




6.650







4.758




6.538







3.795




7.199







3.665




7.086







2.748




7.548







2.681




7.459







1.802




7.765







1.776




7.709







0.921




7.890







0.914




7.859







0.070




7.934







0.000




7.931















Referring now to

FIG. 19A

, a vertical candela trace is seen which is characteristic of the principal reflectors of the invention and particularly of the principal reflector


200


with the principal reflectors


22


and


190


approximating the vertical candela trace as seen in FIG.


19


A. Use of the principal reflector


22


and


190


with shielding devices such as the flux manager


42


and further with the reflector insert


82


causes said principal reflectors


22


and


190


to more closely approximate the vertical candela trace seen in FIG.


19


A. In the vertical candela trace of

FIG. 19A

, the bottom side of the beam is to the right, the candela distribution being arranged so that the maximum candela will occur at center beam. The vertical candela trace of

FIG. 19A

is essentially the same regardless of set back and mounting height assumptions and are essentially asymmetric with the majority of flux being directed below center beam. A very sharp, nearly linear cutoff occurs above center beam and an exponential behavior is exhibited between center beam and the lower extinction angle. A horizontal candela trace is seen in FIG.


19


B and illustrates that the linear behavior required on either side of the illuminance pattern results in a linear and symmetric illuminance trace with respect to horizontal angle. Differing set back and mounting height assumptions essentially result in distributions with similar occurrence with the beam being linear and symmetric even though maximum value differs as does angular extent from left to right.




The optics of the luminaire assemblies described herein are intended to produce a unique distribution of light characterised by a linear sloping to the front of the luminaire assembly and to the sides with each luminaire providing an illuminance distribution shaped as is seen in

FIG. 20

, a plurality of the luminaire assemblies of the invention in a cluster acting to produce essentially half of a flat cone with the distribution of

FIG. 20

forming a section thereof which is perpendicular to the base of the cone which “halves” the cone with these distributions overlapping to some degree at edges thereof to produce the unique distribution of light provided by the present luminaire assemblies of the invention. It is to be understood relative to

FIGS. 19A

,


19


B and


20


that these figures define ideal distributions for all of the primary reflector assemblies of the invention.




While the invention has been described in light of explicit embodiments thereof, it is to be understood that the invention can be embodied other than as explicitly described and shown herein, the scope of the invention being defined by the recitations of the appended claims.



Claims
  • 1. A reflector assembly for illuminating an area, the reflector assembly comprising a primary reflector having reflective facets which direct light from a lamp onto the area, at least a portion of the light generated by the lamp being directly radiated to the area, the reflector defining an optical chamber, and shielding means mounted within the optical chamber to the primary reflector for blocking that portion of the light from the lamp which otherwise would produce glare and redirecting that light past lamp arc and against surfaces of the reflector and back into a beam directed onto said area.
  • 2. The reflector assembly of claim 1 wherein the lamp is transversely mounted within the optical chamber in a horizontal attitude when the assembly is oriented for operational use.
  • 3. The reflector assembly of claim 1 wherein the shielding means is involutely shaped.
  • 4. The reflector assembly of claim 1 wherein the shielding means is shaped as an involute curve capped by revolving the curve to form a surface of revolution.
  • 5. The reflector assembly of claim 1 wherein the shielding means is shaped as an involute curve and has the equationx=a cos Φ+aΦ sin Φ and y=a sin Φ−aΦ cos Φwhere x and y are variables identifying each locus of the involute curve on a Cartesian coordinate system having the arc of the lamp being placed at x,y=zero; a is a line coincident with a radius of a circle centered at x,y=zero the circle corresponding to a circumference of the lamp; Φ is the angle between the x-axis and the line a; B is a point on the circle at the intersection of the circle and the line a, a tangent to the circle at the point B intersecting the involute curve at a point P, the length of the line BP being equal to the arc length of an arc of the circle from the point B to a point A at the intersection of the arc BA with the x-axis.
  • 6. The reflector assembly of claim 1 wherein the shielding means is disposed above a horizontal centerline of the optical chamber.
  • 7. The reflector assembly of claim 1 and further comprising secondary reflector means disposed within the optical chamber and between the shielding means and reflective inner wall surfaces of the reflector for redirecting flux which would impinge the shielding means to cause the maximum possible flux to exit the reflector assembly at the highest possible angle below center beam without striking the shielding means and without being incident on lamp arc.
  • 8. The reflector assembly of claim 7 wherein the secondary reflector means comprises a plurality of reflective facets, each of the facets being aimed to redirect flux incident thereon.
  • 9. The reflector assembly of claim 1 and further comprising secondary reflector means disposed within the optical chamber and between the shielding means and the reflective inner wall surfaces of the reflector for re-aiming flux blocked by the shielding means to cause the blocked flux to exit the reflector assembly without striking the shielding means and without being incident on lamp arc.
  • 10. The reflector assembly of claim 9 wherein the secondary reflector means comprise a plurality of reflective facets, each of the facets being aimed to redirect flux incident thereon.
  • 11. The reflector assembly of claim 1 wherein the reflective facets are concentric annular facets.
  • 12. The reflector assembly of claim 1 wherein the reflective facets are planar facets formed in concentric annular arrays of facets.
  • 13. The reflector assembly of claim 1 wherein each reflective facet is planar and is aimed to direct light from the lamp into a beam illuminating the area.
  • 14. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector having reflective inner walls and at least partially defining an optical chamber; a lamp mounted within the optical chamber to produce light, at least portion of the light generated by the lamp being directly radiated to the area; and, shielding means mounted within the optical chamber for blocking that portion of the light from the lamp which would exit the reflector assembly as spill light and redirecting the spill light past lamp arc and back into a beam directed onto said area.
  • 15. The reflector assembly of claim 14 wherein the lamp is transversely mounted within the optical chamber.
  • 16. The reflector assembly of claim 14 wherein the shielding means is involutely shaped.
  • 17. The reflector assembly of claim 14 wherein the inner walls of the reflector are formed as annular facets.
  • 18. The reflector assembly of claim 14 and further comprising secondary reflector means disposed within the optical chamber for redirecting light blocked by the shielding means to cause the blocked light to exit the reflector assembly without striking the shielding means and without being incident on lamp arc.
  • 19. The reflector assembly of claim 14 wherein the shielding means is shaped with a section similar to or identical to a circular arc.
  • 20. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector; a lamp mounted in association with the primary reflector, the reflector directing light from the lamp onto the area, portions of the light generated by the lamp being directly radiated to the area; and, means for distributing light from the lamp onto the area in a distribution characterized by an illuminance slope having a greatest illuminance forwardly of the assembly from a highest elevation at a point on the illuminated area nearmost the assembly and downwardly from said highest elevation to each side of the assembly.
  • 21. The reflector assembly of claim 20 wherein the light distributing means comprise reflective facets formed on the primary reflector.
  • 22. The reflector assembly of claim 21 wherein the reflective facets are concentric annular facets.
  • 23. The reflector assembly of claim 21 wherein the reflective facets are planar facets formed in concentric annular arrays of facets.
  • 24. The reflector assembly of claim 21 wherein each reflective facet is planar and is aimed to direct light from the lamp into a beam illuminating the area.
  • 25. The reflector assembly of claim 21 wherein each reflective facet is aimed to direct light from the lamp into a beam illuminating the area.
  • 26. The reflector assembly of claim 20 wherein the light distributing means comprise shielding means mounted within the optical chamber for blocking light from the lamp which otherwise would produce glare and redirecting that light past lamp arc and against surfaces of the reflector and back into a beam directed onto said area.
  • 27. The reflector assembly of claim 26 wherein the shielding means is involutely shaped.
  • 28. The reflector assembly of claim 26 wherein the shielding means is shaped as an involute curve capped by revolving the curve to form a surface of revolution.
  • 29. The reflector assembly of claim 26 wherein the shielding means is shaped as an involute curve and has the equationx=a cos Φ+aΦ sin Φ and x=a sin Φ−aΦ cos Φwhere x and y are variables identifying each locus of the involute curve on a Cartesian coordinate system having the arc of the lamp being placed at x,y=zero; a is a line coincident with a radius of a circle centered at x,y=zero, the circle corresponding to a circumference of the lamp; Φ is the angle between the x-axis and the line a; B is a point on the circle at the intersection of the circle and the line a, a tangent to the circle at the point B intersecting the involute curve at a point P, the length of the line BP being equal to the arc length of an arc of the circle from the point B to a point A at the intersection of the arc BA with the x-axis.
  • 30. The reflector assembly of claim 26 wherein the shielding means is disposed above a horizontal centerline of the optical chamber.
  • 31. The reflector assembly of claim 26 and further comprising secondary reflector means disposed within the optical chamber and between the shielding means and reflective inner wall surfaces of the reflector for redirecting flux which would impinge the shielding means to cause the maximum possible flux to exit the reflector assembly at the highest possible angle below center beam without striking the shielding means and without being incident on lamp arc.
  • 32. The reflector assembly of claim 31 wherein the secondary reflector means comprises a plurality of reflective facets, each of the facets being aimed to redirect flux incident thereon.
  • 33. The reflector assembly of claim 26 and further comprising secondary reflector means disposed within the optical chamber and between the shielding means and the reflective inner wall surfaces of the reflector for reaiming flux blocked by the shielding means to cause the blocked flux to exit the reflector assembly without striking the shielding means and without being incident on lamp arc.
  • 34. The reflector assembly of claim 33 wherein the secondary reflector means comprise a plurality of reflective facets, each of the facets being aimed to redirect flux incident thereon.
  • 35. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector having reflective inner walls and at least partially defining an optical chamber; a lamp mounted within the optical chamber to produce light, at least a portion of the light generated by the lamp being directly radiated to the area; and, shielding means mounted to the primary reflector and spaced from the lamp for blocking that portion of the light from the lamp which would exit the reflector assembly as spill light and redirecting the spill light past lamp arc and back into a beam directed onto said area.
  • 36. The reflector assembly of claim 35 wherein the lamp is transversely mounted within the optical chamber in a horizontal attitude when the assembly is oriented for operational use.
  • 37. The reflector assembly of claim 35 wherein the shielding means is involutely shaped.
  • 38. The reflector assembly of claim 35 wherein the inner walls of the reflector are formed as annular facets.
  • 39. The reflector assembly of claim 35 and further comprising secondary reflector means disposed within the optical chamber for redirecting light blocked by the shielding means to cause the blocked light to exit the reflector assembly without striking the shielding means and without being incident on lamp arc.
  • 40. The reflector assembly of claim 35 wherein the shielding means is shaped with a section similar to or identical to a circular arc.
  • 41. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector; a lamp mounted in association with the primary reflector, the reflector directing light from the lamp onto the area; and, means for distributing light from the lamp onto the area in a distribution characterized by an illuminance slope having a greatest illuminance forwardly of the assembly from a highest elevation at a point on the illuminated area nearmost the assembly and downwardly from said highest elevation to each side of the assembly, the light distributing means comprising reflective facets formed on the primary reflector, the reflective facets being planar facets formed in concentric annular arrays of facets.
  • 42. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector; a lamp mounted in association with the primary reflector, the reflector directing light from the lamp onto the area; and, means for distributing light from the lamp onto the area in a distribution characterized by an illuminance slope having a greatest illuminance forwardly of the assembly from a highest elevation at a point on the illuminated area nearmost the assembly and downwardly from said highest elevation to each side of the assembly, the light distributing means comprising reflective facets formed on the primary reflector, each reflective facet being planar and being aimed to direct light from the lamp into a beam illuminating the area.
  • 43. A reflector assembly for illuminating an area, the reflector assembly comprising:a primary reflector; a lamp mounted in association with the primary reflector, the reflector directing light from the lamp onto the area; and, means for distributing light from the lamp onto the area in a distribution characterized by an illuminance slope having a greatest illuminance forwardly of the assembly from a highest elevation at a point on the illuminated area nearmost the assembly and downwardly from said highest elevation to each side of the assembly, the light distributing means comprising shielding means mounted within the optical chamber for blocking light from the lamp which otherwise would produce glare and redirecting all of that light past lamp arc and against surfaces of the reflector and back into a beam directed onto said area.
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