Area lighting device using discrete light sources, such as LEDs

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG.
1, an LED cluster 2 is disclosed, comprising a plurality of individual LEDs (light emitting diodes) 4 disposed along a number of rows and columns on a circuit board 6 that may include heat transfer surfaces, such as that disclosed in U.
S.
Pat.
No.
5,857,767.
The LEDs may be white or red or green or blue, a mixture of these wavelengths or other individual or mix of wavelengths, visible or otherwise.
Typical LEDs exhibit angularities between 4.
degree.
-30.
degree.
, meaning that the light generated is mostly contained within a cone of angles ranging 4.
degree.
-30.
degree.
, with the vertex originating at the LED, the side of the axis of the cone representing maximum light intensity and the side of the cone representing 50% light intensity.
The cone angle is also referred to as a primary angle.
An example of an EL (electroluminescent) panel is disclosed in U.
S.
Pat.
No.
4,482,580.
To obtain more light than an LED cluster or an EL panel can provide and stay within the 10 ft.
sup.
2 projected area dictated by existing pole design for wind load, a hollow light box 8 having interconnected side walls 10, a top wall 12 and open bottom 14 is formed, where one or more of the side walls or top wall 12 is comprised of the LED cluster 2 and/or EL panel, as best shown in FIG.
2.
The lighted side of the LED cluster or EL panel faces into the interior of the light box and the light collected within exits through the bottom opening 14.
The light box 8 provides greater surface area for discrete light and/or other radiation sources without increasing a predetermined projected area, which is the area projected by the panel unto a plane perpendicular to the plane of the opening 14.
Specific panels can be assigned to different wavelength-specific light emitting sources which can be independently controlled for light output.
Individual panels may also provide for more than one type of light source and wavelength.
For example, each of the three primary colors can be assigned on the inner surface of the light box 8