Luminaire for Roadway and Area Lighting

The present invention relates to a novel roadway luminaire which is useful in that it may be adjusted to conform to a particular standard of illumination.

Luminaires which are employed in earlier lighting system are generally of the "box cut-off" and "prismatic lens" types. The "prismatic lens" type luminaire relies on refraction of light rays from the source lamp to direct light to the high angle zone generally defined between 65 and 75 degrees in relation to a line projected downwardly from the luminaire which is perpendicular to the ground surface. The "prismatic lens" system has a tendency to produce light at higher than normal viewing angles (generally above 75 degrees) which are undesirable and often termed as "glare" within the normal angles of vision of a motorist.

The "box cut-off" luminaire such as the type shown in the U.S. Pat. No. 4,053,766 greatly reduces glare at normal viewing angels while still producing a broad distribution of light similar to that of "prismatic lens" type luminaire. However, the "box cut-off" luminaire suffers restrictions in that the portion of the reflector directing light to the high angles of emission is quite small, about a 30 degree sector around the light source. Thus, the remaining reflectors are restricted to directing light to the lower angles of emission which may produce an undesirable result, by creating disuniform levels of illumination on the ground surface ("hot spots").

Moreover, the standard for roadway and area lighting may be described by the "illuminance" system or the "luminance" system. The former systems depends on the amounts of light falling on a ground surface and the latter depends on the he light reflected by the ground toward the viewer. As may be apparent, the "luminance" standard thus takes into consideration the different levels of specularity of the road surface. For example, a diffuse surface tends to reflect light in all directions and requires a pattern of distribution from a lighting system which is very much like the one for the "illuminance" system. On the other hand, a highly specular roadway surface, one which tends to reflect light outwardly from the source must be reinforced on the downstream side of the luminaire and diminished on the upstream side of the luminaire to produce a more uniform luminance on the surface, as viewed by a motorist driving in that direction.

A roadway luminaire which addresses and solves these problems encountered in the lighting field would be a great advance therein.

In accordance with the present invention a novel and useful roadway luminaire usable under illuminance or luminance standards of illumination is provided.

The roadway luminaire of the present invention utilizes a source of light which may be mounted in a housing. The housing may include a bottom opening and a side opening positioned at a selected angle in relation to the bottom opening. Both the bottom and side openings would permit the passage of light from the source. Lenses may be supported by the housing across the bottom and side openings.

The invention also provides for a first reflector supported by a housing a certain distance from the source light. The first reflector would include a reflecting or specular surface which would direct light from the source and away from the luminaire through the bottom opening. The first reflector may include means for adjusting the direction of the light reflected therefrom.

A second reflector is also provided and supported adjacent the first reflector. The second reflector possesses a second surface for reflecting light away from the source of light to one side of the same. Thus, means for adjusting the direction of light emanating from the first reflector maybe employed to reflect light in relation to the light coming from the second reflector. The second reflector would reflect light to one side of the source of light and through the side opening of the housing.

The luminaire of the present invention may also embrace the use of a third reflector such that the first reflector is positioned between the second and third reflectors. The third reflector would also have a reflecting surface for reflecting light from the source to another side of the source of light and through the side opening of housing. The means for adjusting the direction of the light reflected from the first reflector may also serve to block light from the source to the third reflector.

In many cases a fourth reflector may be employed in the luminaire of the present invention. The fourth reflector is located on the one and another side of the source of light and is displaced from the second and third reflectors toward the bottom opening of the housing. The fourth reflector, again, has a specular surface for directing light from the source to the one and another side of the source of light. Such light would pass through the bottom opening of the housing.

For area lighting uses the second reflector may surround the light source and the first reflector. In such a situation the second reflector would reflect light outwardly through a 360.degree. arc.

It may be apparent that a novel and useful roadway luminaire has been described. It is therefore an object of the present invention to provide a roadway luminaire which is an improvement of the conventional box cut-off type luminaires which delivers higher levels of illumination at high angels of emission.

It is another object of the present invention to provide a roadway luminaire which possesses a great energy efficiency, thus permitting wider spacing between a plurality of such luminaires in a particular area being lighted.

It is yet another object of the present invention to provide a roadway luminaire which possesses an increased zone of reflection of light directed at high angels of emission.

It is another object of the present invention to provide a roadway luminaire which is usable under the "illuminance" or "luminance" standards of illumination, since light may be adjustably reflected in the upstream or downstream areas in relation to a moving vehicle.

It is further object of the present invention to provide a roadway luminaire which produces very low glare from all normal viewing angles.

Another object of the present invention is to provide a luminaire suitable for area illumination which produces intense light projected at high angles of emission with minimal glare.

It is a further object of the present invention to provide luminaire which produces a symmetrical pattern of light distribution through a 360.degree. arc.

The invention possesses other objects and advantages especially as concerns particular characteristics and features thereof which will become apparent as the specification continues.

FIG. 1 is a side elevational view of the luminaire of the present invention in use.

FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.

FIG. 4 is a bottom plan view of the luminaire of the present invention shown in FIGS. 1-3.

FIG. 5 is a partial bottom plan view of the upper reflector section of the luminaire of the present invention having the lamp, lenses, and lower reflector sections removed.

FIG. 6 is a sectional view of another embodiment of the luminaire of the present invention.

FIG. 7 is a side elevational view of the luminaire of the present invention in use with a moving vehicle.

FIG. 8 is a bottom right perspective view of the reflector system of the luminaire of the present invention.

FIG. 9 is a sectional view similar to FIGS. 2 and 6 depicting another embodiment of the present invention.

FIG. 10 is a bottom perspective view of the embodiment of the present invention shown in FIG. 9.

FIG. 10A is a bottom perspective view of an embodiment of the split first reflector.

FIG. 10B is a bottom perspective view of another embodiment of the split first reflector.

FIG. 11 is a schematic plan view of one-way roadway with luminaires of the present invention in place.

FIG. 12 is a schematic plan view of a narrow two-way roadway with luminaires of the present invention in place.

FIG. 13 is a schematic plan view of a wide two-way roadway with the luminaire of the present invention in place.

FIG. 14 is a bottom plan view of another embodiment of the present invention employed for area lumination.

FIG. 15 is a sectional view taken along line 15--15 of FIG. 14.

FIG. 16 is a bottom plan view of the upper reflector system of the embodiment of the present invention shown in FIGS. 14 and 15.

FIG. 17 is a schematic view showing the approximate patter of light distribution pattern of the embodiment of the present invention shown in FIGS. 14-16.

For a better understanding of the invention reference is made to the following detailed description of the preferred embodiments thereof which will become apparent as the specification continues.

Various aspects of the present invention will evolve from the following detailed description of the preferred embodiments which should be referenced to the hereinabove described drawings.

The invention as a whole is shown in the drawings by reference character 10 and includes as one of its elements a source of light 12. Light source 12 includes an arc tube 14 which extends along axis 16, best shown in FIG. 2. A clear envelope enclosing arc tube 14 is preferred. Source of light 12 is supported within a housing 18, FIGS. 2, 3 and 6, which has top portion 20, bottom portion 22, and side portion 24. Bottom portion 22 and side portion 24 include openings 26 and 28 having lenses 30 and 32 thereacross. source of light or lamp 12 fits into socket 34 mounted within socket bracket 36 which is held to housing partition 38. Electrical conductors 40 electrically link lamp 12 and socket 34 through the appropriate ballast, electronics, and the like which are found within box 42 at the top of housing 18, FIGS. 2, 3 and 6. For example, ballast and starter mechanism serial number 123-93-509 manufactured by Universal Transformer Company in Patterson, N.J. would suffice. Bracket 38 serves as the floor to the box 42. A gasket 44 surrounds the top 20 and forms a seal between the same and side lens 32. Flange 46 connected to partition 38 partially surrounds gasket 34 to the rear of lamp 12, FIG. 2. Latch 48 fastened to mounting member 50 engages side lens 32 and holds the same in place. Mounting member 50 would connect to pole 52 by any suitable means in the known art. Side lens 32 pivots about hinge pin 52 when latch 48 is released. In addition, partition 38 would also hinge downwardly about hinge pin 54 when latch 48 is released. Thus, access is gained to the lamp 12 and the ballast and associated electronics within box 42. Of course, conductors 40 which are held to partition 38 by grommet 56 would not hinder a rotation of side lens 32, socket 36, and partition 38, since a slack length of conductor 40 would be provided above partition 38 within box 42.

Side lens 32 is constructed with a rim 58 which supports bottom lens 30 as well as lower reflector system 60, FIG. 2. Rotation of side lens 32 downwardly about hinge pin 52 would also permit access to bottom lens 30 and lower reflector system 60 for maintenance purposes.

With reference to FIGS. 2, 3 and 4, lower reflector system 60 includes reflecting surfaces 62, 64 and 66 on either side and generally to the rear of arc tube 14. Reflector surfaces 68 and 70 are found forward of arc tube 14; reflector surface 70 being stepped to prevent light from returning to the rear portion of lamp 12, often referred to as the "house side" 72 of luminaire 10. Likewise, the area to the front of lamp 12 is generally referred to as "street side" 74 of luminaire 10.

Returning to FIG. 3 it may be seen that light emanating from arc tube 14 and ultimately reflected by lower reflector systems 60, would lie in a sector having an angle A. Angle A has been found to be generally a maximum of 30 degrees. The light reflected within the annular sector of angle A would generally be "high" angles of emission, generally between 65 degrees and 75 degrees in relation to vertical plane 76. Rays 72 and 74 represent such light reflected from lower reflector system 60.

Luminaire 10 also is constructed with an upper reflector system 78. Upper reflector system 78 entails a first reflector 80 which is positioned generally above arc tube 14. Second reflector 82 and third reflector 84 flank first reflector 80. First reflector 80 includes a bracket 86 which is fastened to ribs 88 and 90 which depend from top 20.

Again referring to FIG. 3 it may be seen that light passes from source 12 through a gap 92 formed between lower reflector system 60 and upper reflector system 78. Specifically, light emanates in an annular sector generated by angle B. Light passing through gap 92 is reflected from upper reflectors 82 and 84 at high angles of emission. this reflected light, shown by rays 94 and 96, strike side lens 32 at angles which are close to a perpendicular angle. It has been found that the loss of light through reflection from side lens 32 is less than ten percent, a far better result than is achieved by passing all light through lens 30. Thus, the light directed outwardly by reflectors 82 and 84 are used to reinforce light reflected by lower reflector system 60, i.e. at high angles of emission. It should be noted that top 20 includes a flange 98 which may serve as a weather shield.

Looking at FIGS. 2 and 5, 7 and 8 upper reflector system 78 also includes reflectors 100, 102 and 104 which also reflect light outwardly and toward the street side of luminaire 10 at generally high angles of emission. As FIG. 5 depicts, reflectors 100, 102 and 104 are fastened by fastening means, such as set screws, to top 20. Rear reflectors 106, 108 and 110 are fastened to partition 38 via fastening means 112. These rear reflectors generally direct light upwardly toward the upper reflector system 78, thus, controlling the light shining to the house side of luminaire 10.

With reference to FIG. 1 it may be seen that light is distributed by luminaire 10 to a zone 114 which is the heretofore described high angle zone of emission. Light is also distributed to zone 116 at lower angles of emission. Zone 118 represents the glare zone i.e. light having an angle of emission generally above 75 degrees. It has been found that the candle power of luminaire 10 peaks at an angle of emission of as much as 75 degrees and gradually diminishes as the angle of emission decreases, FIG. 3. The arrangement of upper reflector system 78 and lower reflector system 60 around light source 12, also serves as a glare cut-off system , i.e. the light emanating from luminaire 10 greatly decreases above approximately 75 degrees.

Luminaire 10 may have application to roadway lighting using the "illuminance" system or the "luminance" system. The former includes a basis which simply measures the horizontal foot-candle level on the lighted surface at each point. On the other hand the latter measures the amount of light reflected from the surface to the observer's line of sight. Consequently, the reflectance characteristics of the road surface and the direction of travel of the observer relative to the direction of travel of the observer relative to the luminaire must all be taken into account. Where a roadway surface is highly diffuse the required patterns of distribution in the "luminance" standard is very much like the one for the "illuminance" system. However, where a roadway surface is highly specular, light directed toward an observer in motor vehicle 120 "upstream" will be highly visible. Meanwhile, light directed downstream from motor vehicle 120 will largely reflect away from the motorist and appear greatly diminished in intensity. Therefore the light directed downstream must be reinforced significantly to produce a more uniform luminance on roadway surface 122 which is highly specular. Luminaire 10 may include means 124 for adjusting the direction of light reflected from reflector 80 in relation to the light reflected from the reflecting surface 82. Means 124 may take the form of replacing reflector 80 with a reflector 80A, FIG. 6. Also, bracket 86 would be replaced by a new bracket 86A resulting in a cutoff or blocking of light to reflector 84. In addition, the light reflected from reflector 80A would include high angle light represented by ray 156. Rays 126, 127 and 129 represent light thrown at proper downstream angles causing the proper distribution of light on the surface 122 such that the peak intensity occurs about 60 degrees from pole 52. Reflector 84 could be removed in this embodiment.

Turning to FIG. 7 it may be seen that the downstream light from the FIG. 6 luminaire reinforced as required by highly specular surface 122 under the luminance standard. it has been determined with luminaire 10 of FIG. 6 that the upstream peak diminishes as required from the embodiment shown in FIG. 3, but peaks at close to 75 degrees. Also, the downstream candle power has been reinforced up to approximately 68 degrees from the vertical plane 76. In FIGS. 6 and 7 it should be noted that reflector 82 of FIG. 3 has also been replaced by reflector 80A.

In summary, the above described changes constituting means 124 for adjusting the direction of light reflected for first reflector 80 may be easily accomplished without affecting the structure of luminaire 10. In other words, the specularity of the reflectors and the shielding of the lamp remain the same in both configurations shown in FIGS. 3 and 6.

It should be noted that luminaire 10 is anticipated for use with similar luminaires along a roadway on either side of the same. In the case where luminaires are staggered along a roadway, reflector 80A may be alternated from the configuration shown in FIG. 6, to an opposite configuration which blocks the light to reflector 82A.

With reference to FIGS. 9, 10, 10A and 10 B luminaire 130 (FIGS. 9 and 10) is shown as a different embodiment of the present invention. Reflector 80A ("luminance" standard) of FIG. 6 has been split into a pair of reflector sections 126 and 128, FIGS. 9 and 10, which reflect light to opposite sides of light source 12. FIG. 10A depicts reflector sections 126 and 128 in a substantially parallel orientation. In FIG. 10B reflector section 129 of the illuminance standard, has been substituted for reflector section 128. Section 129 corresponds to the general contours of reflector 80 of FIG. 3.

Turning to FIGS. 11-13, it may be observed that various luminaires having reflectors as above described possess separate applications in relation to roadways. For example, in FIG. 11, luminaires 132, 134, 1236 and 138 include reflectors 126 and 128 of FIGS. 9 and 10 but are oriented same way, lying substantially parallel to one another, FIGS. 10A, to reinforce downstream light according to arrows 126A and 128A. The arrows 126A and 128A of luminaires 132, 134, 136 and 138 bear the same reference character plus the letter "A" as the reflectors shown in FIGS. 9-10. FIG. 11 illustrates the use of the luminaire of the present invention on one-way roads 140 and 142 with the luminaires 132, 134, 136 and 138 mounted on either side of roadways 140 and 142.

FIG. 12, in contrast, utilizes the exact configuration of reflectors 126 and 128 of FIGS. 9 and 10 i.e. oppositely oriented, on a narrow two-way road 144.

The FIG. 13 application employs a reflector 126 oriented as shown in FIGS. 9 and 10 and an illuminance type reflector 129 (FIG. 10B) having the configuration of reflector 80, FIG. 3. Luminaires 146, 148 and 150 are on a wide two-way road 152. The directional arrows in FIG. 13 represent the light reinforcement for both the "luminance" and "illuminance" systems.

Moreover, it has been found that at a typical mounting height of 30 feet, luminaire 10 may be laterally spaced at approximately 61/4 mounting heights. This compares favorably to five mounting heights of the prior art devices. Thus, with wider spacing capabilities fewer luminaires of the type show in the present invention are required to light a surface.

FIGS. 14-17 illustrate another embodiment of the present invention where a luminaire 210 includes a light source 212. Said 212 possess an arc tube 214 which extends along 216. Arc source 12 is mounted within housing 218 having top portion 220, bottom portion 222, and side portion 224. Bottom portion 222 and side portion 224 include openings 226 and 228 spanned by lenses 230 and 232, respectively. Lamp 212 fits into socket 234 and bracketed to partition 238 in the same manner as luminaire 10, FIGS. 2 and 3. The ballast mechanism, electronics, and conductors are normally found within box 242 at the top of housing 218. A gasket 244 surrounds the top 220 of housing 218 and forms a seal between the same and side lens 232. Latch 248 and mounting member 250 would connect to a pole as is the case with luminaire 10. Side lens 232 is constructed with a rim 252 which supports bottom lens 230 as well as a lower reflector system 254. Side lens 232 frictionally engages gasket 44 within glare flange 256 and may be hingedly attached in the same manner as luminaire 10, best shown in FIG. 10.

Lower reflector sytem 254 includes reflecting surfaces 258, 260 and 262 which extend about axis 264. With reference to FIG. 14 it may be seen that axis 216 and axis 266, perpendicular to axis 216, extended to the periphery of luminaire 210 form quardrants 268, 270, 272, and 274 moving clockwise around the depiction of luminaire 210. Lower reflector system 254 is symmetrical about axis 264 to produce a symmetrical light distribution generally shown in FIG. 17 by plurality of ray arrows 276. Dashed line 278 represent a line of equal illumination of ground surface 280 below luminaire 210.

Luminaire 210 also includes an upper reflector system 282. Upper reflector system 282 is constructed with a faceted first reflector 284 which is positioned generally above arc tube 214. Second reflector 288 includes sections 286, 288, 290 and 292 of upper reflector system 282 surround first reflector 284. With reference to FIG. 16. Thus, reflector sections 286, 288, 290, and 292 surround light source 212 and direct light into quardrants 268, 270, 272 and 274, respectively. Reflector sections 286 and 288 are fastened to ribs 294 and 296 which depend from top portion 220. Reflectors 290 and 292 are also fastened to ribs which depend from top portion 20 (not shown). It should be noted that first reflector 284 includes a central portion 298 which is generally in the shape of pyramid having facets 302, 304, 306 and 308.

Light emanating from source 212 passes through gap 300 between lower reflector system 254 and upper reflector system 282 at high angles, in manner similar to luminaire 10. Unlike luminaire 10 light is evenly distributed in each of the quadrants 268, 270, 272, and 274, FIG. 17. In this regard first reflector 284 and second reflector 285 may be constructed with a smooth surface i.e. without facets.

While in the foregoing embodiments of the present invention have been set forth in considerable detail for the purpose of making a complete disclosure of the invention, it may be apparent to those of skill in the art that numerous changes may be made in such detail without departing from the spirit and principles of the invention.