FIELD

[0001] This invention relates to the field of lighting. More particularly, this invention relates to a low-profile LED light fixture. BACKGROUND

[0002] Generally there are four basic types of chicken houses. A broiler house houses chicks from one day old through seven weeks, where they are fed and then processed for meat. A pullet house houses chicks from three days old until they begin laying eggs, after which they are delivered to breeders. A breeder house is where mature chickens lay eggs to supply chicks for the broiler houses. A layer house is where mature chickens lay eggs for consumption.

[0003] Lighting has been a constant challenge in chicken houses. Dust, moisture, and chemical exposure affect the consistency of light and the life of bulbs. Chicken houses are typically cooled by large fans that create excessive amounts of dust. Dust on light sources causes a decrease in light intensity on the ground surface. Growers using bulb- type lighting must spend resources to manually clean bulbs at the end of each grow-out cycle. Also, light levels need to be consistently varied at different times during the day and throughout the life cycle to reduce stress levels, thereby controlling the chicken's attitude and appetite which enhances their growth. [0004] LED light bulbs have been used recently in chicken houses to save energy and improve light conditions. However, there are unique problems with LED bulbs, including flicker during the dimming process, moisture incursion, collection of dust, fragility, and high turnover rates.

[0005] What is needed, therefore, is a reliable, flicker-free, waterproof, and robust LED lighting fixture for use in chicken houses. SUMMARY

[0006] The above and other needs are met by a light fixture configured for attachment to a standard ceiling fixture junction box. The light fixture includes a metal base having a hole pattern that matches a mounting screw hole pattern of the standard ceiling fixture junction box. A printed circuit board is attached to a bottom surface the metal base, and a circular array of LEDs is attached to an outer perimeter of the printed circuit board. A domed cover is attached to the bottom surface of the metal base that covers the printed circuit board and the circular array of LEDs. The domed cover is molded from clear plastic through which light from the LEDs may pass. [0007] In some preferred embodiments, the light fixture includes power terminal wires extending from the top surface of the metal base that connect to standard AC power cable wires.

[0008] In some preferred embodiments, the domed cover includes apertures that are aligned with the hole pattern in the metal base. The apertures receive mounting screws that attach the light fixture to the standard ceiling fixture junction box.

[0009] In some preferred embodiments, the domed cover includes a translucent ring portion disposed over the circular array of LEDs for providing improved dispersal of light from the LEDs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other embodiments of the invention will become apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:

[0011] FIGS. 1-4 depict a low-profile light fixture according to an embodiment of the invention; [0012] FIG. 5 depicts a domed cover of the low-profile light fixture that is removed from the fixture;

[0013] FIG. 6 depicts a printed circuit board and array of LEDs of the low-profile light fixture with the domed cover removed; and [0014] FIGS. 7-9 depict a low-profile light fixture according to a preferred embodiment. DETAILED DESCRIPTION

[0015] The figures depict an LED light fixture 10 designed to be installed to a standard ceiling light fixture junction box. The light fixture replaces standard fixtures that receive screw-in bulbs, thereby lowering the overall profile. The low-profile fixture 10 is waterproof, dustproof and chemical-proof. The low-profile aspect of the fixture provides for low levels of dust collection and easy cleaning. The fixture 10 includes two or four mounting holes 20 to match mounting screw hole patterns of standard ceiling junction boxes. A preferred embodiment includes two mounting holes 20 for attaching to the most common hole pattern for ceiling junction boxes. [0016] Preferred embodiments of the fixture include a large aluminum base 12 on which a printed circuit board (PCB) 16 is mounted. While also serving as a mounting structure, the base 12 dissipates heat away from the PCB, thereby extending the life of the LEDs. As shown in FIG. 8, preferred embodiments include a UL-listed EPDM rubber washer 26 on the top surface of the base 12 to provide a water-tight seal between the base 12 and the junction box to which it attaches. In various embodiments, the outer perimeter of the base 12 is octagonal or circular, and is preferably circular to maximize the heat dissipation area.

[0017] The LEDs are preferably arranged on the PCB 16 in a circular array 18. In one embodiment of the fixture 10, there are fifty-six LEDs in the array 18. A driver-on-board (DOB) control circuit on the PCB 16 controls the operation of the LEDs. The LED array preferably comprises surface mounted diode (SMD) LED chips having model number SMD 2835. Although the array of LEDs 18 is circular in a preferred embodiment, other geometries for the array could be used, such as rectangular or octagonal.

[0018] Due to the brightness of these LEDs, each fixture 10 can provide up to five foot candles at ground level over a 400 square foot area, or ten foot candles over a 200 square foot area, and dimmable to zero foot/candles. Thus, the fixtures 10 can be placed on 20- foot centers on the ceiling of the chicken house, each having a 30-foot wide footprint, thereby providing wall-to-wall lighting coverage over 360 degrees with substantially no shadows. By comparison, standard LED bulbs must be placed on 10-foot centers.

[0019] A domed cover 14 is attached to the bottom surface of the base 12 and covers the PCB 16 and the circular array 18 of LEDs. The domed cover 14 is preferably molded from clear plastic through which light from the LEDs may pass. A plurality of screws, such as three or six, may be used to fasten the domed cover 14 to the base 12. To provide a waterproof and dustproof seal, an annular waterproof gasket 28 is disposed between the domed cover 14 and the base 12, as shown in FIG. 7. In preferred embodiments, the domed cover includes a translucent ring portion 22 disposed over the circular array 18 of LEDs for providing improved dispersal of light from the LEDs.

[0020] Preferred embodiments of the fixture have the following features: 25 Watt power consumption Operable with dimmer switches with no flicker 3000K color temperature 2125 lumens - 120V/ AC supply voltage

5 foot candles at ground level, dimmable to less than 0.25 foot candles 10 year expected lifetime

[0021] In a preferred embodiment, power terminal wires 24 extend through an aperture in the top surface of the metal base 12 for connecting to standard AC power cable wires in a ceiling junction box (FIG. 2). As shown in FIG. 8, to provide an environmental seal, the power terminal wires 24 are preferably disposed in a dust-tight and waterproof wire harness 30 (TP65 rated). In a preferred embodiment, the wire harness 30 includes a quick-disconnect connector 32 as shown in FIGS. 8 and 9, so that the light fixture 10 can be easily removed and replaced by a non-electrician. Preferred embodiments also include a ground wire 34 for Energy Star certification.

[0022] The foregoing description of preferred embodiments for this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.