Abstract:
A ceiling mount lighting fixture includes a channel, a channel cover, and a light source including a plurality of light-emitting diodes. The channel cover includes two sides that intersect in a V-shaped base, with light-emitting diodes mounted on each side. The light-emitting diodes emit light at cone angles that overlap at the base of the channel cover. The fixture may include a diffuser and an end cap positioned on each end of the channel, each end cap including a groove. A plurality of strips may be located on the diffuser, each strip moveable from a first position on the diffuser a distance from the end caps to a second position in which the strip engages the groove on one of the end caps, thereby serving as a light trap to block light from exiting gaps between the diffuser and end caps.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional application No. 61/708,272, filed Oct. 1, 2012, entitled “Ceiling mount fixture,” the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to light fixtures, and in particular to ceiling mount fixtures for light-emitting diode (“LED”), fluorescent or other luminaires. 
     BACKGROUND 
     Ceiling mount lighting fixtures for use in LED, fluorescent and other lighting applications are known. In a typical configuration, a ceiling mount fixture includes a channel, a channel cover, a light source (e.g., fluorescent bulbs or LEDs), a diffuser and end caps. In ceiling mount fixtures, the channel is mounted on the ceiling. The channel cover is positioned within the channel, and a power source (such as a ballast for a fluorescent light) and wiring is contained between the channel and the channel cover. In a traditional fluorescent ceiling mount fixture, fluorescent lamps are mounted on lamp sockets located at each end of the fixture so as to extend along the length of the fixture. A diffuser is positioned over the channel, and light from the light source passes through the diffuser and into the area to be illuminated. End caps are provided to enclose the ends of the fixture and impart a polished appearance to it. 
     There continues to be a need to facilitate assembly of and access to the various components of these light fixtures as well as better capture and distribution of the light emitted by the light sources in these fixtures. 
     SUMMARY 
     The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this patent, all drawings and each claim. 
     In one embodiment, a ceiling mount lighting fixture includes a channel, a channel cover and a light source including a plurality of light-emitting diodes. The channel includes a first side and a second side that intersect in a V-shaped base, wherein at least one of the plurality of light-emitting diodes is mounted on the first side of the channel cover and at least another of the plurality of light-emitting diodes is mounted on the second side of the channel cover. The plurality of light-emitting diodes mounted on the channel cover emit light at cone angles that overlap at the base of the channel cover. 
     In an embodiment, the plurality of light-emitting diodes emit light at a cone angle of approximately 120 degrees. 
     In certain embodiments, the V-shaped base includes an internal angle defined by an angle between the first side and second side, and the internal angle is from about 170 to about 100 degrees. In other embodiments, the internal angle is from about 150 degrees to about 140 degrees. 
     In some embodiments, the ceiling mount fixture includes a diffuser having a first diffuser end plate located on a first end of the diffuser and a second diffuser end plate located on a second end of the diffuser opposite the first end, and a first end cap mounted on a first end of the channel and a second end cap mounted on a second end of the channel opposite the first end. One of the first diffuser end plate and the first end cap includes at least one pin and the other of the first diffuser end plate and the first end cap includes at least one hook-like structure that engages the at least one pin of the one of the first diffuser end plate and the first end cap. 
     In other embodiments one of the second diffuser end plate and the second end cap includes at least one pin and the other of the second diffuser end plate and the second end cap includes at least one hook-like structure that engages the at least one pin of the one of the second diffuser end plate and the second end cap. 
     In yet other embodiments, a diffuser includes a first diffuser end plate located on a first end of the diffuser, a second diffuser end plate located on a second end of the diffuser opposite the first end, a first end cap mounted on a first end of the channel and a second end cap mounted on a second end of the channel opposite the first end. The first diffuser end plate includes a first hook-like structure, the second diffuser end plate includes a second hook-like structure, the first end cap includes a first pin and the second end cap includes a second pin. The first pin on the first end cap engages the first hook-like structure on the first diffuser end plate, and the second pin on the second end cap engages the second hook-like structure on the second diffuser end plate, such that the diffuser is retained by the channel and rotatable about the first pin and second pin. 
     In some embodiments, one of the channel cover and channel includes at least one tab extending therefrom, wherein the tab comprises a distal portion and a proximal portion narrower than the distal portion, and the other of the channel and channel cover includes at least one T-slot for receiving the tab, wherein the T-slot comprises a wider portion and a narrower portion. The tab is movable within the T-slot from a first position in which the distal portion of the tab may pass through the wider portion of the T-slot to a second position in which the tab is retained in the T-slot by the narrower portion of the T-slot, such that the channel cover is retained by the channel. 
     In an embodiment, a ceiling mount lighting fixture includes a channel having two ends, a light source, a diffuser, an end cap positioned on each end of the channel, wherein each end cap includes a groove, and a plurality of strips located on the diffuser, each strip moveable from a first position on the diffuser a distance from the end caps to a second position in which the strip engages the groove on one of the end caps. 
     In some embodiments, methods are described for assembling the fixture, and in particular for installing the channel cover over the channel, for installing the diffuser and diffuser end plates to the channel and end caps, and for installing the strips over gaps between the diffuser and diffuser end plates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the present invention are described in detail below with reference to the following drawing figures: 
         FIG. 1  is a bottom perspective view of one embodiment of a light fixture. 
         FIG. 2  is an exploded view of a fluorescent light fixture according to one embodiment with Detail A and Detail B showing features of the invention. 
         FIG. 3  is an exploded view of an LED light fixture according to one embodiment, with Detail A and Detail B showing certain features of the invention. 
         FIG. 4  is bottom perspective view of an embodiment according to  FIG. 3  with Detail A showing certain features of the invention. 
         FIG. 5  is a top perspective view of an embodiment with Detail A showing certain features of the invention. 
         FIG. 6  is partial bottom perspective view of one embodiment of the invention. 
         FIG. 7  is an end cross-section view of an embodiment of the invention. 
         FIG. 8  is a top partial perspective view of one embodiment of the invention. 
         FIG. 9  is a top partial perspective view of an embodiment of the invention. 
         FIG. 10  is a bottom partial perspective view of one embodiment of the invention. 
         FIG. 11  is a top partial perspective view of an embodiment of the invention. 
         FIG. 12  is an end cross-section view of one embodiment of the invention. 
         FIG. 13  is a bottom perspective view of an embodiment of the invention. 
         FIG. 14  is a bottom partial perspective view of one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. 
     With reference to  FIGS. 1-5 , embodiments of the present invention include a ceiling mount fixture  100  having a channel  110 , a channel cover  150  mounted to the channel  110 , a light source such as a plurality of fluorescent lamps  120  (see  FIG. 2 ) or a plurality of LEDs  125  (see  FIG. 3 ), a diffuser  130  and end caps  140 . While embodiments of the invention are described as including fluorescent lamps  120  and LEDs  125 , other light sources are also contemplated herein. In ceiling mount fixtures, the channel  110  is mounted on the ceiling, although it is certainly contemplated that such would not always be the case. The channel cover  150  is positioned over the channel  110  so that a power source such as a ballast for a fluorescent bulb or a driver for LEDs and associated wiring (not shown) are contained between the channel  110  and the channel cover  150 . As shown in Detail A and Detail B of  FIG. 2 , the channel cover  150  may include a plurality of notches  152  that engage a plurality of humps  154  on the channel  110  so as to facilitate alignment of the channel  110  over the channel cover. 
     The channel  110 , channel cover  150  and end caps  140  may independently be formed from known lighting fixture materials, including but not limited to aluminum, steel, non-ferrous metal and polymeric materials. 
     In one embodiment, the channel cover  150  is positioned and retained on the channel  110  through the use of a notched tab. With reference to  FIG. 3  (Detail A and Detail B),  FIG. 4  (Detail A) and  FIG. 5  (Detail A), in certain embodiments, at least one notched tab  190  extends from one side of the channel cover  150  and a corresponding T-slot  200  is provided in the sides of the channel  110 . The T-slot  200  has a wider part  205  and a narrower part  210  (which is narrower than the wider part  205 ). The at least one tab  190  is notched such that the portion of the tab closest (proximal) the channel cover (denoted as proximal portion  192 ) is narrower than the portion of the tab distal from the channel cover (denoted as distal portion  194 ). The distal portion  194  of the tab  190  engages the wider part  205  of the T-slot  200 . Once the tab  190  is inserted into the T-slot  200  it is pushed back along the narrower part  210  of the T-slot  200  so that it cannot disengage from the T-slot  200 . The width of the proximal portion  192  of the tab  190  may be approximately the same, or less than, the width of the narrower part  210  of the T-slot  200 . The width of the distal portion  194  of the tab  190  may be approximately the same, or less than, the width of the wider part  205  of the T-slot  200 . It will be recognized, however, that the width of the distal portion  194  of the tab  190  should be greater than the width of the narrower part  210  of the T-slot  200 , or the tab  190  can disengage from the T-slot  200 . 
     Lances  215  may be provided in the channel  110  to retain the tab  190  within the narrower part  210  of the T-slot  200  and thereby prevent the tab  190  from moving back towards the wider part  205  of the T-slot  200  where it could disengage from the channel  110 . Once the at least one tab  190  is positioned in the T-slot  200 , the channel cover  150  is rotated to cover the channel  110 . The other side of the channel cover  150  may be secured to the channel  110  with screws or another type of fastener. 
     It will be recognized that the tab  190  need not necessarily be located on the channel cover  150  with the T-slot  200  located on the channel  110 . Thus, in certain embodiments (not shown), the T-slot  200  is located on the channel cover  150  and the tab  190  is located on the channel  110 . The tab  190  engages the T-slot  200  as described above. 
     In a traditional fluorescent ceiling mount fixture, fluorescent lamps  120  are mounted on lamp sockets  122  located at each end of the channel  110  so as to extend along the length of the fixture  100  adjacent the channel cover. In one embodiment, LEDs are used instead of fluorescent lamps. In such embodiments where the light source for the fixture  100  includes LEDs  125 , the channel cover  150  may have a “V” or other similar shape, as illustrated in  FIGS. 3 ,  6  and  7 . The base  165  of the “V” may be located at the center of the channel cover  150  as shown, or in other configurations if desired for alternative light distribution schemes. For example, the base  165  of the “V” may be skewed towards one side of the channel cover  150 , so that one side of the channel cover  150  is longer than the other, which would move the centerline of the LEDs, and the concentration of light emitted by the LEDs, away from the actual center of the channel cover  150 . 
     The LEDs  125  and associated printed circuit boards (PCBs)  170  may be mounted to the channel cover  150  on each side of the “V”. The “V” shaped configuration thus allows for LEDs  125  on opposite sides of the “V” to have overlapping cone angles β of light emitted from the LEDs  125 .  FIG. 7  illustrates an exemplary overlap of LED  125  cone angles β, with each LED having a cone angle β of approximately 120 degrees that overlap in the center of the diffuser  130  to prevent a dark shadow from arising along the center of the diffuser. It will be recognized that the LED  125  cone angle β may be adjusted by selecting different LED configurations, such that the LED  125  cone angle β may vary from a very narrow angle (e.g., almost zero degrees or a point source of light) to a very large angle (e.g., up to approximately 200 degrees). 
       FIG. 7  shows the “V” of the channel cover  150  having an internal angle Θ of approximately 150 degrees, such that each side of the “V” is approximately 15 degrees from the horizontal. The “V” may incorporate other angles, however, as desired for alternative light distribution schemes. In some embodiments, each side of the “V” may be from about 5 to about 40 degrees from horizontal (i.e., the “V” has an internal angle Θ of about 170 degrees to about 100 degrees). In other embodiments, each side of the “V” may be from about 10 to about 30 degrees from horizontal (i.e., the “V” has an internal angle Θ of about 160 degrees to about 120 degrees). In certain embodiments, each side of the “V” may be from about 15 to about 20 degrees from horizontal (i.e., the “V” has an internal angle Θ of about 150 degrees to about 140 degrees). 
     With reference to  FIGS. 2 ,  3  and  8 - 12 , a diffuser  130  is positioned over the channel  110 , and light from the light source (fluorescent lamps  120  or LEDs  125 ) passes through the diffuser  130  and into the area to be illuminated. End caps  140  are provided to enclose the ends of the fixture  100  and impart a polished appearance to it. 
     The diffuser  130  may be formed of a translucent material such as a polymeric material. In certain embodiments, such as when used in LED fixtures, the diffuser may include a diffusing film applied to the diffuser to soften the light from the LEDs. Exemplary, though not limiting, types of diffusers include prismatic, smooth and frosted diffusers. In some embodiments, the diffuser  130  is retained on the fixture  100  by diffuser end plates  135  (located on each end of the diffuser  130 ) engaging end caps  140 , as discussed below. In some embodiments, the diffuser end plates  135  are provided only on the ends of the diffuser  130  (i.e., they do not extend along the entire length of the diffuser). In one embodiment illustrated in  FIG. 9 , the diffuser  130  is curved, and the diffuser end plates  135  are similarly curved to conform to the shape of the end of the diffuser  130 . 
     The diffuser end plate  135  may be formed from known lighting fixture materials, including but not limited to a polymeric, aluminum, steel or non-ferrous metal material. The diffuser end plates  135  may be connected to the diffuser  130  by known methods, including but not limited to sonic welding and adhesives. The diffuser end plates  135  may also be integrally formed with the diffuser  130 . In the embodiment shown in  FIGS. 8-12 , the diffuser end plate  135  is a polymeric material and is sonically welded to the diffuser  130 . In other embodiments, the diffuser end plate may snap onto the diffuser or be otherwise configured to attach to the diffuser  130 . 
     As mentioned, the diffuser  130  (and diffuser end plates  135  connected thereto) are retained on the fixture by end caps  140 . An exemplary end cap  140  and its interaction with a diffuser end plate  135  is shown in FIGS.  8  and  10 - 12 . The end cap  140  is typically affixed to an end panel  115  connected to the channel  110  with one or more fasteners, such a screw  142 . In one embodiment, a pin  144  is provided on each side of each end cap  140 . A hook-like structure  137  is similarly provided on each side of each diffuser end plate  135 . 
     To install the diffuser end plates  135 —and the diffuser  130  which is attached thereto—to the end caps  140 , the hook-like structure  137  provided on one side of each diffuser end plate  135  is positioned on the pin  144  on one side of each end cap  140 . The diffuser  130  is then rotated towards the other side of the fixture  100  and the hook-like structure  137  on the opposing side of each diffuser end plate  135  is hooked on the other pin  144  on each of the end caps  140 . In other words, the diffuser end plates  135  are snapped onto the end caps  140  of the fixture  100  via hook and pin engagement to thereby retain the diffuser  130  on the fixture  100 . The diffuser  130  is thus attached to the fixture  100  at the ends of the diffuser  130 . Moreover, the hook-like structure  137  on either side of the diffuser end plate  135  may be disengaged from its associated pin  144  thereby creating a bi-direction hinge in that the diffuser  130  may be disengaged and rotated about the pins  144  on either side of the diffuser end plates  135  for easy access into the fixture. 
     Although the diffuser end plate  135  is shown in the figures as having two hook-like structures  137  and the end cap  140  as having two pins  144 , in certain embodiments each diffuser end plate may have only one hook-like structure and its associated end cap may have only one pin for engaging the hook-like structure. In such embodiments, one side of the diffuser end plate may be screwed, bolted or otherwise attached a side of the end cap, while the other side of the diffuser end plate may include the hook-like structure for engaging a pin on the end cap. It will be recognized that in such an embodiment, the diffuser would only hinge in one direction, and only by removing the screw/bolt/etc. from the side of the diffuser end plate. 
     It will be recognized that the pins  144  need not necessarily be located on the end caps  140 ; rather, the pins  144  may be configured to extend directly from the channel  110  and engage the hook-like structures  137  on the diffuser end plate  135 . In such an embodiment (not shown), the diffuser end plate would thus be directly connected to the channel  110 . 
     In other embodiments (not shown), the location of the hook-like structures  137  and pins  144  can be reversed such that the hook-like structures  137  are located on the end caps  140  (or channel  110  as described above) and the pins  144  are located on the diffuser end plate  135 . In such embodiments, the diffuser  130  could still hinge relative to the channel, with the pins on the diffuser end plate  135  rotating within the hook-like structures  144  located on the end cap  140  or channel  110 . 
     With reference to  FIGS. 13 and 14 , in some embodiments strips  180  of material are positioned around the diffuser  130 . The strip  180  may be formed of any suitable material, including polymeric materials such as acrylic. In other embodiments the strip may be formed from steel or aluminum. The strips  180  are moveable along the length of the diffuser  130 . Once the end caps  140  are positioned on the ends of the fixture  100 , and the diffuser  130  is installed, each strip  180  of material is slid towards, and partially received in, one of the end caps  140 . Specifically, the end caps  140  may include a groove  146  into which the strip  180  may slide. In this way, the strips  180  span the gap  185  between the diffuser  130  and the end cap  140 , thereby preventing light from escaping through the gap  185  (i.e., serving as a light trap) and also helping to prevent the diffuser  130  from disengaging from the fixture  100  (i.e., serving as an additional support to hold the diffuser  130  within the groove  146  of the end cap  140 ). 
     In certain embodiments, the strip  180 , as installed on the diffuser  130 , may have a smaller radius than the diffuser  130 , resulting in a tight fit between the strip  180  and the diffuser  130 . In this manner, the strip  180  remains securely installed on the diffuser  130  with the ability to slide along the length of the diffuser  130 . With the diffuser  130  installed and the strip  180  properly seated within the groove  146  in the end cap  140 , length changes of the diffuser  130  due to normal temperature variations should not be great enough for the strip  180  to fully disengage from the groove  146  in the end cap  140 , maintaining the light-trapping and securing properties discussed above. The strip  180  thus compensates for manufacturing tolerances and normal thermal expansion of the diffuser  130 . 
     Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.