Patent Abstract:
A fluorescent light fixture comprises a substantially rectangular housing, a ballast located in the housing, a fluorescent lamp for emitting light in response to a first signal received from the ballast, a reflector made as a unitary structure for focusing the emitted light onto a pre-selected area, and a sensor for detecting an activity or inactivity, such that a second signal is transmitted to the ballast for triggering the first signal.

Full Description:
BACKGROUND OF THE INVENTION 
   The present invention is related to light fixtures. More specifically, the present invention is related to a fluorescent light fixture having an all-aluminum housing for lightweight construction, a uniquely-shaped reflector for reflecting light in a downward direction for maximum intensity and for optimizing the light ray pattern to achieve high efficiency, and a motion sensor uniquely situated on the fixture. 
   Light fixtures with fluorescent lamps are widely used in commercial buildings, such as warehouses, manufacturing facilities, etc. These types of light fixtures, however, are also used in residential environment, such as kitchens, garages, etc. Optical and functional efficiency, among other things, contributes to the widespread use of such light fixtures in those aforementioned areas. 
   A fluorescent light fixture typically has an elongated housing for holding, among other things, a ballast, long tubular lamps, and a reflector. The ballast provides power to the lamps from the conventional AC source. The reflector is provided for concentrating and directing the emitted light in a downward direction. 
   As known to those skilled in the art, fluorescent lighting is advantageous in energy efficiency over incandescent lighting. According to some tests, fluorescent lights produce 50–100 lumens/watt compared to approximately 15 lumens/watt for incandescent bulbs. 
   Even though fluorescent lights are more efficient than incandescent bulbs, they are harder to control. The electrical discharge that excites the mercury vapor has to be started quickly and reliably, and then the current must be controlled from continuing to rise until it burns out the tube. The starting and control function is handled by a ballast. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a fluorescent light fixture, which is, among other things, lightweight and efficient. 
   The above and other objects are achieved by a fluorescent light fixture. According to one embodiment of the present invention, a fluorescent light fixture comprises a substantially rectangular housing, a ballast located in the housing, a fluorescent lamp for emitting light in response to a first signal received from the ballast, a reflector made as a unitary structure for focusing the emitted light onto a pre-selected area, and a sensor for detecting an activity or inactivity, such that a second signal is transmitted to the ballast for triggering the first signal. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, and in which like reference characters refer to like or corresponding parts: 
       FIG. 1  shows one embodiment of the fluorescent light fixture in accordance with the present invention; 
       FIG. 2  shows in detail a housing for one embodiment of the fluorescent light fixture in accordance with the present invention; 
       FIG. 3  shows in detail a reflector for one embodiment of the fluorescent light fixture in accordance with the present invention; 
       FIG. 4  shows dimensions of the reflector for one embodiment of the fluorescent light fixture in accordance with the present invention; and 
       FIGS. 5A ,  5 B and  5 C are a set comprising various parts of a photometric test report for one embodiment of the light fixture according to the present invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  displays one embodiment of the present invention, presenting a general overall structure of the inventive fluorescent light fixture according to this embodiment, as incorporated into a commercially successful product. As illustrated in this figure to provide a general overview of the inventive device, the fluorescent light fixture includes an elongated, substantially rectangular housing  10 . Housing  10  supports reflector  14 , which is not shown in this figure, but illustrated and fully described in detail hereinbelow. Shown in this figure are a number of long tubular fluorescent lamps  12  supported by reflector  14 . In this particular embodiment, reflector  14  has capacity for six lamps. Lamps  12  are shown inserted into sockets  16 , which are described and shown hereinbelow. Sockets  16  are electrically connected to wires  22  for carrying current from a power source to the lamps. As known to those skilled in the art, the lamp is a long narrow glass tube with two electrical connections on each of the metal caps. The caps seal the ends of the tube filled with such noble gases as argon, neon, etc. Mercury is also deposited into the tube. When AC power is supplied to the ballast, an electric discharge is established in the tube, which produces ultraviolet radiation. To produce light in the visible range, the inside wall of the tube is coated with phosphor. When the ultraviolet light strikes the inside wall, it produces excitations of the phosphor electrons and causes the phosphor coating to fluoresce with a bright glow. 
   Continuing with the general overall description of the embodiment of the present invention, housing  10  also includes ballast  18  (not shown in  FIG. 1 ) for supplying power to the lamps  12 . High-frequency electronic ballast  18  converts the power from the conventional AC source in order to provide high luminous efficiency, as known to those skilled in the art. 
   Housing  10  further comprises sensor  20 . In one embodiment of the present invention, sensor  20  is a motion detector for detecting any motion or absence thereof within a pre-selected 2-dimensional area or 3-dimensional space. A signal is then sent to turn the light fixture on or off depending on the selected function and a predetermined period of time. 
     FIG. 2  shows in more detail one embodiment of the fluorescent light fixture according to the present invention. Referring to  FIG. 2 , housing  10  comprises sockets  16  at both ends of the substantially rectangular structure. Wires  22  provide electrical connection between each socket  16  and ballast  18 . 
   Also connected to ballast  18  is sensor  20  via wires  24 , as shown in  FIG. 2 . In one embodiment of the present invention, sensor  20  detects any motion or absence thereof within a pre-selected 2-dimensional area or 3-dimensional space. If after a predetermined period of time and within the pre-selected area, the motion or absence thereof is detected by sensor  20 , a signal is transmitted to ballast  18  via wires  24  to activate or de-activate the lamps. It will be appreciated that sensor  20  is attached to housing  10  via two stems  26  and  28 . Connecting stems  26  and  28  is knob  30 , which provides rotational movement of sensor  20  in 2 planes, vertical and horizontal. The sensor is thus adjustable in 2 planes for better detection. It will be further appreciated that sensor  20  is positioned slightly off-center with respect to a hypothetical axis running parallel to the shorter sides  32  of housing  10  and dividing housing  10  into two equally measured parts. Such location of sensor  20  on housing  10  allows the inventive light fixture to be placed on a ceiling in such a way as to avoid pipes, heavy-duty cables, railings and other obstructions, which might interfere with the positioned light fixture. It will be appreciated even further that housing  10  comprises additional alternative three locations  34 , as shown in  FIG. 2 , which might be used to re-position and attach sensor  20 , if needed or desired for getting around obstructions when mounting the light fixture. It will be appreciated still further that housing  10  is substantially an all-aluminum structure to provide lightweight and corrosion resistance to the inventive light fixture. 
     FIG. 3  illustrates in more detail a reflector in one embodiment of the fluorescent light fixture according to the present invention. In particular, reflector  14  is a single piece. Its unitary structure is made substantially entirely of aluminum. As the result, the inventive light fixture is lightweight and corrosion-free. 
     FIG. 4  shows representative dimensions of the reflector in one embodiment of the fluorescent light fixture according to the present invention. According to this embodiment of the present invention, reflector  14  includes four channels for fluorescent lamps. The configuration of reflector  14 , as shown in  FIG. 4 , achieves optimization of the reflected light pattern and efficiency equal to or greater than 92%. 
     FIGS. 5A ,  5 B and  5 C are a set comprising various parts of a photometric test report for one embodiment of the light fixture according to the present invention. The test was performed for the four-lamp fixture of the present invention. 
   The fluorescent light fixture according to the present invention is typically mounted on a ceiling. One of the inventive features of the present invention is transverse mounting. In particular, the inventive light fixture according to the present invention is mounted in such a way that its housing major axis is perpendicular to an isle in order to illuminate it, for example. This unique mounting provides better light concentration and focus than traditional mounting. 
   It is understood that sensor  20  in the fluorescent light fixture according to the present invention is not limited to motion detection and may be detecting other events, such as ambient light, etc. 
   It is further understood that the fluorescent light fixture according to the present invention is not limited to 4 lamps and may contain 1, 2, 3, 6 or 8 lamps. 
   It is still further understood that the fluorescent light fixture according to the present invention is not limited to one ballast and may comprise multiple ballasts. 
   While the invention has been described and illustrated in connection with preferred embodiments, many variations and modifications as will be evident to those skilled in this art may be made without departing from the spirit and scope of the invention, and the invention is thus not to be limited to the precise details of methodology or construction set forth above as such variations and modification are intended to be included within the scope of the invention.

Technology Classification (CPC): 5