Patent Publication Number: US-7594737-B2

Title: Garage light luminaire with circular compact fluorescent emergency lighting optics

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of application Ser. No. 11/535,138, filed Sep. 26, 2006, which will issue under U.S. Pat. No. 7,374,310 on May 20, 2008, which is a continuation of application Ser. No. 10/865,301, filed Jun. 10, 2004, now U.S. Pat. No. 7,121,684, the disclosure of which is hereby incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to the lighting arts, and in particular to an electronic auxiliary lighting system for a high intensity discharge lamp. More particularly, the auxiliary lighting system of the present invention uses as a light source a high output compact fluorescent lamp. 
   2. Description of Related Art 
   A high-intensity discharge (HID) lamp will extinguish when power to the HID lamp is interrupted. Momentary power interruptions, such as a lightning strike or someone inadvertently hitting the on/off switch, will cause the HID lamp to extinguish. An extinguished HID lamp will not immediately re-ignite upon the restoration of power to the HID lamp because gases within the HID lamp must be cooled before the HID lamp will re-ignite. With the power restored, restarting a hot HID lamp can take several minutes. Even when they are cool, and easy to start, HID lamps still take up to 2 minutes to come to full bright after they are ignited. 
   The garage building industry puts a great deal of stock in emergency lighting standards. The industry likes to see a certain minimum amount of light along path of egress in their structures during power interruptions. Accordingly, auxiliary lighting control circuitry has been used for automatically lighting an auxiliary light source, such as an incandescent lamp, following a brief power interruption of a HID lamp. It is known in the art to use quartz lamps to meet these emergency lighting requirements. Round and square garage lights having a HID lamp as a primary light source and a quartz auxiliary lamp have been used for many years. The premise is that when the HID lamp, located at the center of the fixture, is not on the quartz lamp, which is typically a smaller cylindrical incandescent lamp mounted to the side of the HID lamp, is lit to provide emergency illumination. However, there are inherent problems with these current practices of providing auxiliary light to garage lighting systems. 
   The quartz lamps that are typically used as auxiliary lamps are short lived and are very inefficient in converting electric power into lumens. This causes problems with continued reliability, maintenance, and the ability to meet auxiliary lighting needs. A significant problem associated with these current practices is that the quartz lamps are not located at the photometric center of the fixture. This causes the pattern of light projected from the auxiliary lamp to lack uniformity and thus portions of the lighted area are only dimly lit. Additionally, during normal operation the quartz lamp mounted on one side of the fixture blocks or refracts light from the HID lamp located at the center of the fixture. This causes the quartz lamp, during normal operation of the HID lamp, to form a shadow on the area being lit. It has also been found that emergency incandescent lamp sources are inherently glary and consistently mounted off of the centerline of the fixture, causing the luminaire to be aesthetically unappealing. 
   What is needed in the garage lighting industry is an auxiliary lamp system that provides emergency light without the problems found in the current systems. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a luminaire having both a main lamp and an auxiliary lamp where the auxiliary lamp efficiently and reliably provides illumination when the main lamp fails to provide adequate illumination. 
   Another object of the present invention is to provide a luminaire having an auxiliary and a main lamp that provide uniform illumination without asymmetries to the area below. 
   A further object of the present invention is to provide a luminaire that has a main lamp and an auxiliary lamp where neither the main lamp or the auxiliary lamp cause shadowing. 
   It is yet another objective of the present invention to provide a luminaire having a main lamp and an auxiliary lamp so that the luminaire is aesthetically appealing. 
   These objects and others are accomplished according to the present invention by providing a luminaire for illuminating a wide area and having an auxiliary lamp that reliably emits adequate light efficiently and uniformly without causing shadowing of the light emitted from the main lamp and is aesthetically appealing. 
   The luminaire of the present invention includes a housing having a lower lamp mounting surface. This housing may becircular, square, or even irregular in shape. The lamp mounting surface may be reflective and may have prisms to increase the efficiency of the luminaire in lighting a desired area. A main light source, preferably a high intensity discharge (HID) lamp, is centrally mounted onto the lamp mounting surface and extends downward. This vertical arrangement provides for optimum illumination efficiency and life of the HID lamp. An auxiliary lamp is also mounted onto the lamp mounting surface. This auxiliary lamp may be a high output compact fluorescent circular lamp and located centrally about the lamp mounting surface surrounding a portion of the HID lamp. The auxiliary lamp surrounds, substantially at its center, a portion of the combination of the main lamp socket and main lamp and may have a light emitting portion closer to the lamp mounting surface of the housing than the light emitting portion of the main lamp. A lamp&#39;s light emitting portion is typically a filament or gaseous volume where light is generated within the lamp. Additionally, the luminaire optionally may have a main barrel shaped reflector surrounding a light emitting portion of the main lamp and mounted at a distance from the lamp mounting surface so that a large portion of the light being emitted from the auxiliary lamp is reflected to the area below by the barrel reflector. A downward portion of the light being emitted from the auxiliary lamp and much of the light reflected from the lamp mounting surface is redirected by the barrel reflector to provide an illumination pattern similar to the pattern created by the normal operation of the HID lamp. The luminaire may also have a lamp cover attached to the housing enclosing the auxiliary lamp, main lamp, lamp mounting surface, and optionally a barrel reflector. This lamp cover may have prisms forming a lens that spreads the light being emitted from the auxiliary lamp, main lamp, and light reflected from the lamp mounting surface and optional barrel reflector to desired areas to be illuminated. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an embodiment of the luminaire of the present invention showing the high output compact fluorescent circular auxiliary lamp, main HID lamp, housing, lamp mounting surface, and their placement within the luminaire. 
       FIG. 2  is a lower perspective view of the luminaire in  FIG. 1  showing an embodiment having a barrel reflector and its location within the luminaire. 
       FIG. 3  is an exploded view of the luminaire in  FIG. 2  showing the relationship of the components of the luminaire. 
       FIG. 4  is a view of the high output compact fluorescent circular auxiliary lamp, socket, and mounting brackets of the present invention. 
       FIG. 5  is a side view of an embodiment of the garage light of the present invention having a lamp cover. 
       FIG. 6  is a perspective view of an alternative embodiment of the garage light of the present invention having an alternative embodiment of a lamp cover. 
       FIG. 7  is a photometric comparison of light levels achieved by the auxiliary lamps in the prior art and the light levels achieved by the auxiliary lamp of the present invention. 
       FIG. 8  is the photometric data of light levels achieved by the auxiliary lamps in the prior art. 
       FIG. 9  is the photometric data of light levels achieved by the auxiliary lamp in the present invention. 
       FIG. 10  is a perspective view of an embodiment of the luminaire of the present invention wherein the luminaire has a square shape. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention may best be understood by reference to the following description taken in conjunction with the accompanying figures. The figures illustrate specific embodiments in which the invention may be practiced and it is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention. 
     FIG. 1  is a perspective view of the garage luminaire  10  of the present invention showing the high output compact fluorescent circular auxiliary lamp  13 , main HID lamp  14 , housing  11 , lamp mounting surface  12 , and their placement within luminaire  10 . In this embodiment of luminaire  10  the housing  11  is round or circular in shape. It is to be understood that housing  11  may be round, square, rectangular, oval or even irregular in shape and be within the scope of the present invention. 
   The housing  11  may hold the wiring, ballasts, auxiliary light switch, battery, and any other electrical equipment that may be associated with the main lamp  14  and auxiliary lamp  13 . On the bottom of housing  11  is a lamp mounting surface  12 . This lamp mounting surface  12  in this embodiment is round and covers most of the lower portion of housing  11  and may serve as the lower wall of housing  11 . Lamp mounting surface  12  may have an anodized reflective surface, and as shown in the embodiment in the figures, may have ridges and troughs forming facets that reflect the light from the main lamp  14  and auxiliary lamp  13  to the desired areas. 
   Main lamp  14  is a HID lamp that is mounted into HID lamp socket  15  which is centrally located within lamp mounting surface  12 . Lamp socket  15  is attached to lamp mounting surface  12  at a recessed center of lamp mounting surface  12  so that light emitted from lamp  14  is at a specific predetermined distance from lamp mounting surface  12 . 
   Auxiliary lamp  13 , a high output compact fluorescent circular lamp, is mounted annularly around lamp socket  15  and main lamp  14 . Auxiliary lamp  13  is mounted to lamp mounting surface  12  with circular lamp socket  16  and lamp mounting brackets  401 . Circular lamp socket  16  is attached near the outer edge of lamp mounting surface  12  at a non-recessed portion at a specific predetermined distance from lamp mounting surface  12  and provides an electrical connection to the lamp  13  electrodes and power supply, not shown. 
   Main lamp  14  extends downwardly from lamp mounting surface  12  while auxiliary lamp  13  is a circular lamp that has its light emitting portion closer to lamp mounting surface  12 . This configuration allows main lamp  14  to project its light downwardly and radially with the aid of lamp mounting surface  12  and optionally barrel reflector  201  without having shadowing or refraction from auxiliary lamp  13  since main lamp  14  has its light emitting portion below auxiliary lamp  13 . Additionally, both auxiliary lamp  13  and main lamp  14  have light emitting portion centrally located with lamp mounting surface  12 . This configuration provides symmetry to the luminaire  10  which improves the consistency in the direction and pattern of light being emitted from the luminaire  10  when the source of light is changed between HID lamp  14  and auxiliary lamp  13 . The symmetry of lamp  14  and lamp  13  also improves the aesthetics of the luminaire  10 . 
     FIG. 2  is a perspective view of the luminaire  10  of the present invention showing the placement of an optional barrel reflector  201  within the luminaire  10 . Barrel reflector  201  has an inner reflective surface and surrounds a portion of main lamp  14 . Barrel reflector  201  reflects a portion of the radial light being emitted from main lamp  14  to the desired area below. In the embodiment of the barrel reflector  201  shown, the inner reflective surface has facets to disperse the light within the desired area to be lit. Barrel reflector  201  has mounting flanges  202  that hold barrel reflector  201  to a lamp cover  501 . Barrel reflector  201  is typically frustospherical in shape and is mounted at a specific distance from lamp mounting surface  12  so that a large portion of light emitted from main lamp  14 , auxiliary lamp  13 , and reflected by lamp mounting surface  12  encounters the inner reflective surface of barrel reflector  201  and is reflected to the desired area below. Therefore, operation of either HID lamp  14  or auxiliary lamp  13  enables the luminaire  10  to produce a consistent and even light pattern on the area below. 
     FIG. 3  is an exploded view of the luminaire  10  of the present invention showing the relationship of the components of the luminaire  10 . Housing  11  and lamp mounting surface  12  are shown as being joined to form an enclosure. In this embodiment, lamp mounting surface  12  is a reflective bottom surface of housing  11 . It should be understood that housing  11  may have a bottom surface to which a reflective lamp mounting surface  12  may be attached. This exploded view also shows auxiliary lamp  13  and main lamp  14  in a spatial relationship where it can be seen that the light being emitted from main lamp  14  is not impeded or refracted by auxiliary lamp  13  and hence does not create a shadow on the area to be lit. Additionally, barrel reflector retaining tabs  301  are shown here. In this embodiment, barrel reflector  201  is made up of a plurality of facets having slots and retaining tabs  301 . Retaining tabs  301  aid in holding barrel reflector  201  together and providing strength to the frustospherical structure of barrel reflector  201 . 
     FIG. 4  is a view of the high output compact fluorescent circular auxiliary lamp  13 , socket  16 , and mounting brackets  401 . In this embodiment, mounting brackets  401  and auxiliary socket  16  are arranged at 120° intervals about the circular auxiliary lamp  13 . 
     FIGS. 5 and 6  are views of the luminaire  10  of the present invention having alternative embodiments of a lamp cover ( 201  and  601 ). Specifically,  FIG. 5  shows a side view of an embodiment of the garage light of the present invention having a lamp cover  501 . Lamp cover  501  has prisms  502  on an inner surface located forming a lens located above barrel reflector  201 . These prisms  502  are vertically extending ridges having sides at about 45° toward the optical center of the luminaire  10 . In another embodiment, not shown, the ridge sides vary in angle toward the optical center of the luminaire so that light is focused toward alternative areas. These prisms  502  spread the light laterally causing the upper part of cover  501  to glow and reduce the glare that is associated with the garage luminaires in the prior art. Also shown in  FIG. 5  is a gap  503  between barrel reflector  201  and auxiliary lamp  13 . Gap  503  represents the distance between the light emitting portion of auxiliary lamp  13  and barrel reflector  201 . In the embodiment not having barrel reflector  201 , gap  503  represents a distance between the auxiliary lamp  13  and the light emitting portion of lamp  14 . This embodiment of lamp cover  501  has a lower smooth surface that covers the bottom of barrel reflector  201 . Also shown here is the location of flange  202  on lamp cover  501  which supports the barrel reflector  201  within luminaire  10 .  FIG. 6  shows perspective view of the round garage light of the present invention having lamp cover  601 . Lamp cover  601  may have prismatic surfaces on exterior and/or interior side to direct light emitted from the lamps  13  and  14  and reflective surface  12 . Incorporation of prismatic surfaces on lamp cover  601  typically causes the lamp cover to glow and directs the light to desired areas, thus eliminating the need for barrel reflector  201 . These prismatic surfaces on lens  601  may be vertical, horizontal, rounded, square, or other configuration or shape as desired to refract the light being emitted from luminaire  10  to the desired locations. Additionally, the prismatic surfaces increase the aestethics of luminaire  10 . 
     FIG. 7  is a photometric comparison of light levels achieved by the auxiliary lamps in the prior art  701  and the light levels achieved by the auxiliary lamp of the present invention  702 . Photometric tests were performed to verify symmetric distribution of light from the auxiliary or emergency lamp  13 . These lighting patterns were generated by having the luminaires ten feet from the floor area below. The dark circle in the prior art light distribution  701  and the light distribution found in the present invention  702  designate the location of the luminaire above the light pattern. The light pattern of the prior art  701  is asymmetrical since the quartz auxiliary lamps are not centrally located about the photometric center of the luminaire. Additionally, the main HID lamp and socket shadow a portion of light being emitted from the quartz auxiliary lamp of the prior art. Conversely, the light pattern  702  emitted from the auxiliary lamp  13  of the present invention is symmetrical and has no shadowing from HID lamp  14  or socket  15 . The barrel reflector  201  and lamp mounting surface  12  reflect the light emitted from auxiliary lamp  13  evenly onto the surface below. 
     FIGS. 8 and 9  are isofootcandle representations of the comparison of light levels achieved by the auxiliary lamps in the prior art  FIG. 8  and the light levels achieved by the auxiliary lamp of the present invention as shown in  FIG. 9 . The grid lines in these figures represent ten square feet of floor area while the isofootcandle lines represent footcandles of illumination of the lighting patterns in  FIG. 7 . This numeric representation of the photometric data of light levels achieved by the quartz auxiliary lamps of the prior art in  FIG. 8  and the photometric data of light levels achieved by the auxiliary lamp  13  of the present invention as shown in  FIG. 9  clearly shows the symmetrical illumination of the present invention as compared to the asymmetrical illumination of the prior art. The illumination pattern of the prior art  FIG. 8  has areas of intense illumination (&gt;6 footcandles) and areas of almost no illumination (&lt;125 footcandles) below the fixture. The illumination pattern of the present invention  FIG. 9  is symmetrical and void of the bright and dark areas found in the prior art  FIG. 8 . 
   FIG  10  is aperspective view of an embodiment of the luminaire of  FIG. 1  wherein the luminaire  10  has a square shaped housing  110 . Additionally, shown here is a square lamp mounting surface  112  having kick reflectors  111  attached to the corners of lamp mounting surface  112  for redirecting light from the corner of the luminaire toward desired areas of illumination. 
   The Garage Light Luminaire With Circular Compact Fluorescent Emergency Lighting Optics of the present invention is an aesthetically appealing luminaire that has both a main lamp and an auxiliary lamp where the auxiliary lamp efficiently and reliably provides uniform illumination without asymmetries or shadows to the area below. The luminaire of the present invention meets the objectives previously set forth by having a high output compact fluorescent auxiliary lamp, HID main lamp, optional barrel reflector, and optional prismatic lenses within a lamp cover symmetrically located within the luminaire. The horizontal placement of the high output compact fluorescent auxiliary lamp, HID main lamp, optional barrel reflector and lens, in relation to the reflective lamp mounting surface provides for an efficient and consistent distribution of light to the area below.