Illuminating device with reflector portions and voids opposite thereof

A luminaire has a spherical or ovoid reflector formed with asymmetrical voids that allow beams from the lightbulb in the reflector to emerge side-by-side through the voids in opposite directions after reflection from opposite internal surfaces of the reflector.

The present invention relates in general to illuminating and more 
particularly concerns novel apparatus and techniques for providing a light 
reflector for providing two beams in opposite directions with a reflector 
that is relatively inexpensive, relatively easy to manufacture and capable 
of operating for a relatively long time. 
In the design of conventional street lights a single optical system is used 
which sends out strong beams of light in nearly opposite directions, one 
each in the two street directions extending away from the location of the 
light. The light intensity projected directly below the light is less than 
that of the two generally oppositely directed main beams. 
In most street lights the optics are symmetrical on either side of the 
centerline of the luminaire. The optics are so designed that as much of 
the reflected light as possible from one side of the reflector is 
projected at as high an angle as possible without being intercepted by the 
other side of the reflector. This seriously limits the quantity of light 
that can be projected in the two main opposite beams. 
In order to overcome this difficulty, many luminaries are designed with 
refracting transparent fittings extending below the edges of the 
reflector. Where these are used, the reflector is designed to project more 
powerful beams at lower vertical angles than otherwise acceptable, and the 
prismatic patterns of the refractors then lift the two main opposing beams 
to the desired angle. By the use of this optical principle the required 
beam strength is achieved, but at the substantial expense of providing the 
additional refracting accessory. 
It is an object of the present invention to obviate the need for the 
expensive, superfluous refracting accessory by a novel design of the 
reflector, which is made asymmetric in such manner that fully adequate 
beam strengths are realized in the two opposite roadway directions. 
According to the invention, a lighting device for producing at least two 
major beams of light in substantially different directions includes a 
light source within a reflector of generally spherical or ovoid form. The 
reflector surface is formed with voids to allow each major beam to bypass 
each other and provide illumination along a respective direction. This 
reflector has depending first and second side portions on opposite sides 
of the reflector lengthwise axis. These side portions are relatively 
displaced in a direction generally parallel to the lengthwise axis to 
create first and second voids. A light source is supported inside the 
reflector so that the reflector may direct light energy from the light 
source into at least first and second major beams of light in 
substantially different first and second directions respectively after 
reflection from the first and second side portions respectively with each 
of the first and second major beams bypassing each other and emerging from 
the reflector through the voids beside the second and first side portions 
respectively. According to a specific form of the invention two portions 
of the generally ovoid reflector are positioned to project bypassing main 
beams along substantially opposed directions passing through voids of the 
reflector opposite the main reflecting areas to allow transmission of two 
main beams through the respective voids. More specifically, the voids are 
located in two diagonally opposite portions of the lower reflector 
surface. In a specific form the voids are on the right side of the lower 
reflector body when viewed from either side of the reflector. The lighting 
device may be divided lengthwise into four asymmetric sections with a void 
being formed in one of the two upper sections and a second void in the 
diagonally opposite lower section, whereby the remaining sections are 
enabled to project main beams in generally opposite directions through 
respective ones of the voids. According to still another feature of the 
invention, the main reflecting areas may be detachably secured to the 
reflector to permit conversion from bidirectional to monodirectional 
operation by removing one of the two main reflecting areas and adding 
another main reflecting area adjacent to and supplementing the remaining 
main reflector section so that both voids are on the same side of the 
reflector.

With reference now to the drawing and more particularly FIGS. 1A, 1B and 1C 
thereof, there are shown end, side and bottom views, respectively, of an 
embodiment of the invention. These views show a generally ovoid reflector 
form 21 with the entire bottom most portion removed as indicated below 
numerals 1,2,4,5. In addition two other unsymmetrical sections are removed 
from the lower edge, as indicated by 1,2,3 and 4,5,6. 
When viewing the reflector 21 from the side, the cutaway section 1,2,3 
permits the far side of the interior of the reflector to be seen. This 
permits the light from bulb 22 reflected from said far side of the 
interior to emerge from the reflector without interference or conflict 
with the near side of the reflector as would occur in conventional street 
light reflectors having both sides symmetrical. This construction permits 
a design of the reflecting surfaces to be so shaped that there is no limit 
to the quantity of reflected light that can be projected at the desired 
high angles, such as 65, 70, or 75 degrees above nadir. When looking at 
the side view of FIG. 1B, the light reflected from area 2,4,6 is generally 
directed toward the viewer and the light reflected from area 1,3,5 is 
generally directed away from the viewer. 
The geometric shape of the reflector is susceptible to various forms, 
depending upon the height of mounting, the width of the street, and the 
constraints of manufacturing technology. The preferred form is one in 
which the main reflecting areas are made generally paraboloidal, with the 
major axis of the paraboloid extending from the reflector to a specified 
distant point on the street surface, and said surfaces may be provided 
with generally vertical flutings so designed as to spread the reflected 
beam across the width of the street laterally. Other treatments of the 
surface contours are considered within the scope of the invention, such as 
peens, dents, and such other patternings as may be specified by the 
reflector designer to suit the particular street geometry to be 
illuminated. 
Another form of the reflector here contemplated is one in which the major 
patterned reflecting sections 21A,21B,21C,21D are made detachable. The 
luminaire can then be converted from a bidirectional unit to a 
monodirectional unit by removing one appropriate major reflecting section 
and adding another appropriately shaped reflecting section to the opposite 
side, thus making one side of the reflector complete and leaving the other 
side completely open, as shown in FIG. 2. 
The advantages of the invention are, (1) the cost and weight of refracting 
glass or plastic components of the luminaire are saved, (2) the loss of 
light flux in passing through a refracting element is eliminated, (3) the 
danger of falling shards of glass or plastic elements is eliminated, (4) 
collection of rain water, as in completely enclosed refractors is 
eliminated and (5) the expense of periodic cleaning and occasional 
replacement of broken glassware is saved. 
FIG. 3 shows a plan view of a short stretch of roadway illuminated by the 
luminaire of FIGS. 1A-C. The geometric configuration of the luminaire can 
be symmetrical fore and aft about the midsection 3,1,4,6, making the 
luminaire suitable for mounting directly over the centerline of the 
roadway as indicated by 7 in FIG. 3. In this case the reflecting area 
2,4,6 will project its high beam toward a point 8 on the street surface 
and the reflecting area 1,3,5 will project its opposite high beam toward 
point 9 on said surface. 
Many streets are too wide for center-street mounting of the luminaire as 
this would require an impractically long arm overhanging the street. In 
such cases the luminaire is mounted offcenter nearer to the supporting 
pole as shown by 10 in FIG. 3. In this case the reflector designer has the 
option of making the optics asymmetric about said centerline, in which 
case he may prefer to project the high beam from area 2,4,6 toward point 
11 on the street surface and the opposite high beam from area 1,3,5 toward 
point 12 on said surface. It will be seen that this arrangement of the 
optics minimizes the possibility that light from the inner vertical edge 
of one reflecting section will be obstructed by the corresponding inner 
edge of the opposite reflecting section. 
Those skilled in the art may use numerous optical arrangements within the 
principles of the invention. An important feature of the invention is the 
asymmetry of the reflector which permits the escape of ample quantities of 
light in two nearly opposite directions without mutual interference of the 
opposing edges as in conventional street lighting reflectors. 
An advantageous feature of the invention is that the lower edges 2,4 and 
1,5 of the reflector can be extended down lower than is possible with 
conventional reflectors, permitting the acceptance of more light flux from 
the light source 22 to be usefully redirected, and also, providing more 
protection to the fragile glass light source 23 within the reflector from 
missiles and from weather. Should it be found by experience in certain 
unfavorable locations that excessive lamp losses are experienced from 
missiles, clear relatively inexpensive transparent sections can be 
provided to fill in the openings 1,2,3 and 4,5,6. Such sections would be 
shaped with curvatures matching those of the reflector. 
A further advantage of the invention is that the very substantially lower 
cost of the luminaire that is realized by eliminating the heavy, 
expensive, fragile prismatic refractors commonly used with most street 
lights, will permit the reflector to be made larger in size without undue 
increase in luminaire cost. The prevailing use of refracting enclosures in 
current American luminaire designs has forced the use of small luminaire 
sizes which in turn has caused modern street lights to be excessively 
glaring. By enlarging the luminaries the unit brightness can be reduced 
and American street lighting can be made less glaring and night driving 
made more comfortable for the public. The glare from street lights has 
been a traditional concern to the technical bodies concerned with street 
lighting. This invention can make the first substantial breakthrough in 
solving this hitherto unsurmountable difficulty. 
Although the ribbing, fluting, patterning or peening such as shown in the 
drawing is generally preferred because the brightness of the active 
reflecting surface is reduced and made more uniform thereby, these 
treatments are not always necessary and the use of smooth surfaces is 
within the concept of the invention. Whether or not fluting or other 
patterning of the main reflecting surface is used could depend upon the 
kind of lamp used in the luminaire. Fluting could be desirable in order to 
obtain lateral coverage of the street if the lamp is of the type with 
concentrated filament. But many modern lamps using gaseous conductors are 
burned horizontally, causing the actual light source to be very wide. The 
reflected beam from such a lamp would be spread widely on the street 
surface even if the main reflector areas are left smooth. 
Another form of the invention is shown in FIG. 4. In this form the 
asymmetry is vertical instead of horizontal. With the generally ovoid 
reflector form divided generally into upper halves, and these halves again 
subdivided into lengthwise quarters, one upper quarter is removed and an 
opposite lower quarter is also removed. Thus in FIG. 4 upper quarter 13 
and lower quarter 15 are removed, permitting light from upper quarter 12 
and lower quarter 14 to emerge respectively from the luminaire without 
obstruction by the opposite wall of the ovoid. 
In certain applications of the FIG. 4 form of the invention it may be 
advisable to cover either one or both of the openings with clear 
transparent covers conforming to the shape of the luminaire. Transparent 
cover 13', for example, may be needed in locations where heavy snowfall is 
experienced, and similar covers (13' and 15') may be necessary in 
locations where vandalism or smoky atmospheres are excessive. 
It should be understood that the scope of this invention is not limited to 
main beams of equal size. It is anticipated that some task configurations 
may require more illumination intensity in one of the directions than in 
another of the directions. In such case the relative areas of the main 
reflecting sections will differ. 
It should be further understood that the use of this invention is not 
limited to the illumination of roadways. The luminaires may be mounted 
vertically to illuminate long walls or the sides of long low buildings, or 
may even be tipped sideways if necessary to illuminate towers or tall 
buildings, for example, from a high point on an adjacent building or 
structure. 
Referring again to the variety of this invention shown in FIG. 4, it will 
be observed that some of the direct light from the light source will 
emerge at high angles through the clear area 13. In street lighting 
applications this would be wasteful and a source of inefficiency. 
Accordingly a visor 16 can be added to the luminarire to reclaim this lost 
light and redirect it downward toward the roadway where it will be 
utilized. 
There has been described novel apparatus and techniques for illuminating. 
It is evident that those skilled in the art may now make numerous uses and 
modifications of and departures from the specific embodiments described 
herein without departing from the inventive concepts. Consequently, the 
invention is to be construed as embracing each and every novel feature and 
novel combination of features present in or possessed by the apparatus and 
techniques herein disclosed and limited solely by the spirit and scope of 
the appended claims: