The present invention relates to the general field of lighting systems, and in particular, to large area lighting systems.
Large area lighting systems provide various levels of illumination for a variety of applications while minimizing ground level obstructions. Large area lighting systems are often used to illuminate large areas such as highways and stadiums. In densely populated areas, such large area lighting systems tend to “spill” light into nearby residential areas and thus create a nuisance for the residents. Light spillage also contributes to other problems, such as increased light pollution and sky glow. As a result, many jurisdictions have enacted laws preventing the installation of large area lighting systems in close proximity to residential areas.
There have been several unsuccessful attempts by those skilled in the art to address the light spillage issues referenced above. For example, prior art efforts have addressed light spillage problems by placing shields directly on individual lighting fixtures, see for example
Others have addressed the light spillage problem by placing shields inside the lighting fixtures. For example, some prior art luminaires are fitted with internal shields which supposedly control the emission of light only at certain specified angles. Although internal shields generally assist in directing light in a particular direction and help reduce some glare, internal shields fail to control light spillage adequately, and are not adjustable to control the amount of spillage. Internally shielded fixtures have large cut-offs and thus complicate the photometrics used in designing lighting systems. Moreover, fixtures outfitted with internal shields generally increase the expense of lighting fixtures. These fixtures often times deteriorate the light quality provided at the subject location and ultimately focus the light as a spotlight rather than an area light. Light fixtures with internal cut-off shields thus defeat the purpose of large area lighting systems.
Others in the art have fitted various types of external shields onto lighting fixtures. Although some external shields appear to provide adequate cut-off levels, they are often bulky and need to be excessively large to provide acceptable cut-off levels. Thus, prior art externally shielded lighting systems may have high EPA levels and project light similar to that found in spotlights. Thus, fitting lighting fixtures with such external shields reduces the effective and desired lighting area dramatically.
Accordingly, there is a continuing need for an effective and efficient lighting system to provide sufficient light to large areas, such as highways, while eliminating light spillage into adjacent areas, such as residential neighborhoods. What is also needed is a large area lighting system which reduces light pollution and sky glow. What is further needed is a system of maintaining area lighting capabilities at a subject site while achieving very low cut-off. What is still further needed is a system to provide effective light shielding to a plurality of light fixtures while maintaining a reduced EPA level.
The present invention provides an improved large area lighting system. In a preferred embodiment light spillage is minimized or eliminated for an entire lighting unit, rather than just individual fixtures. The improved lighting system provides a light baffle designed to block light spillage from the entire light fixture and maintains a very low effective projected area (EPA) level.
In accordance with an important aspect of the invention, a ‘slat’ style light baffle is provided. The slats are preferably positioned to extend horizontally, thus providing, for example, the best combination of sufficient light delivery, effective light shielding and low EPA. One preferred embodiment provides, for example, a light baffle which may be adjusted in different orientations to increase light delivery to a subject lighting area while minimizing light spillage into a protected area, decreasing light pollution, eliminating unnecessary sky glow and maintaining a low EPA. The orientation of the slat type baffles allows light to selectively pass through or be diffused by the light baffle to the subject lighting area. Conversely, unwanted light cannot directly pass between the light baffle to the protected area, such as a residential area.
In accordance with another aspect of the invention, a preferred embodiment is fully customizable and may be retrofitted into existing lighting systems. Different lengths of slats may be provided to increase light delivery to the subject lighting area or, for example, decrease or eliminate light delivery to the protected area. Slats may be easily exchanged, added on to or removed from the light baffle. In addition, a preferred embodiment may be configured to remotely orient the slats for accurate on-site installation or for routine maintenance as desired. The light baffle of the invention is virtually maintenance free and minimizes the lighting system's overall wind resistance. Thus, the preferred embodiments exhibit a very low EPA level. To further minimize indirect light spillage and enhance lighting capabilities, the slats may be subjected to different surface treatments. For example, the slats may be anodized to provide a flat black surface to lower the reflectivity of the surface. The slats may also be treated with a mirror finish in applications requiring enhanced lighting, such as in stadium lighting.
Still further, a preferred embodiment of the invention provides a large area lighting system comprising a light source and one or more slats configured to control light emitting from the one or more light sources. The large area lighting system may have a plurality of adjustable light sources arranged in various configurations including one or more rectangular rows, one or more circular configurations, one or more semi-circular configurations, one or more arched configurations, one or more staggered formations, and combinations thereof. The slats may be optionally treated to provide a flat black or a mirrored finish depending on the application. Preferably the light baffle slats may be configured to minimize sky glare or glow, the effective projected area and light delivery to a protected area. The light baffle may include a rigid link extending between sets of slats; axles supporting each of the slats; a motor configured to move the rigid link and a remote control configured to control the orientation of the slats.
While the construction and use of preferred embodiments is discussed in detail below, it will be appreciated that the specific embodiments described do not limit the scope of the invention.
As mentioned earlier, large area lighting systems known in the art “spill” light into protected areas such as residential areas. For example, prior art lighting systems, such as lighting system 10, depicted in
A preferred embodiment of the present invention addresses the numerous deficiencies found in prior art lighting systems and provides further advantages. Preferably, a large area lighting system 18,
Lighting system 18 shown is adapted for a high mast type support and is shown supported on and is compatible with a high mast type pole 20. However, system 18 may, for example, be supported on simple industrial and street lighting columns, other high mast structures, hydraulic-based hinged columns and poles with top or bottom latching lifting mechanisms. In the example depicted in,
Lighting system 18, as shown in
Referring now to
The rows of fixture 26 and 28 include frames characterized by spaced apart rectangular so-called ladder type rack assemblies 34 mounted, respectively, on ring assembly 22 at respective brackets 30 and 31,
Referring further to
The number and length of the slats 40 can easily be changed to accommodate the desired lighting. Each slat 40 is preferably oriented to achieve the desired illumination of a subject lighting area while shielding light from the protected area and minimizing EPA. For example, the back-side row of fixtures 28 may be oriented to reduce the light escaping from its light baffles 42 and 42a. Thus, light cannot physically pass between the lamps 32 and a protected area on one side of the baffles 42 and 42a. This is especially important in situations such as in the highway application example, where the highway may run adjacent to residential areas. The light baffles 42 and 42a may be angled in such a manner to block the light and minimize a direct light path to the residential area, while still providing adequate lighting to the highway. In addition, different lengths of slats 40 may be used at different locations to increase or decrease the protection area and/or subject lighting area. The slats 40 of baffles 42 and 42a are preferably positioned horizontally, as shown in
Referring to
Now referring to
It may be important to perform the above-mentioned customizable adjustments to large area lighting system 18 remotely. For example, in the highway application example, a preferred embodiment may have the optional capability to remotely adjust the large area lighting system 18, including minimizing (and possibly eliminating) any light spillage into that residential area. These adjustments to the large area lighting system 18 may be accomplished by employing several different methods including, for example, radio-controlled mechanisms or by hardwiring controls to a ground-accessible service box (not depicted) for pole 20. It should be understood by those skilled in the art that there are a number of other methods to accomplish adjustments to the light baffle 42 and 42a remotely, including, for example, the aforementioned wireless remote control systems.
As shown in
While slat position is important, each slat 40 may be treated to effectuate maximum lighting specifications. For example, the surface of each slat 40 may be treated to reduce glare from the lamps 32 or, conversely provide maximum lighting to the subject lighting area. For example, the surfaces of the slats 40, may be anodized a flat black to lower reflectivity and reduce the glare from the lanterns 32. In other situations, such as in stadium lighting, it may be advantageous to reflect more light from the fixtures (26, 28). Accordingly, in stadium lighting applications and the like, the slats 40 may be highly polished, perhaps even given a mirrored finish. Thus, the highly polished slats 40 reflect more or all of the light to the subject lighting area while minimizing light spillage to surrounding areas outlying the stadium. It should be understood by those skilled in the art, one or selective surfaces of certain slats 40 or all surfaces of the slats may be treated to achieve a desired effect. It should also be understood that slats 40 may undergo other surface treatments not described herein.
As an example of lighting applications other than highway lighting applications,
A preferred embodiment thus provides a versatile large area lighting system 18 in which the orientation and physical properties of the slats 40 control the amount and intensity of the light passing between the lamps 32 and to the subject lighting area. In addition, the large area lighting system 18 controls the amount and intensity of the light passing to any area adjacent to the subject lighting area, thus minimizing any indirect light spillage and reducing light pollution and sky glow while adding only a minimal amount of EPA to the lighting system 18. In addition, a preferred embodiment advantageously is maintenance free and is readily adaptable to meet the lighting design specifications of virtually any application.
Although preferred embodiments of large area lighting systems have been described in detail herein, it will be appreciated that while the description has principally referenced a system for use with a typical large area lighting system, it is to be understood that systems 18 and 54 may be utilized for other large area lighting employing simple industrial and street lighting columns, high mast lighting systems, hydraulic-based hinged columns and poles with top or bottom latching lifting mechanisms.
The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention. For example, the description has principally referenced large area lighting system 18 used in conjunction with highways, however it should be understood that a preferred embodiment may be used in a variety of other large area applications such as those employed in stadiums, power plants, airports, shopping centers, parks, railroad yards, coal mines, commercial parking lots, ports and the like. Those skilled in the art will recognize that various substitutions and modifications may be made to the invention without departing from the scope and spirit of the appended claims.
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