This invention claims the benefit of the Provisional Patent Application No. 60/880,393 filed with the U.S. Patent and Trademark Office on Jan. 16, 2007, which is hereby incorporated by reference in its entirety. 


   BACKGROUND OF THE INVENTION 
   The embodiments of the invention relate to a light emitting diode (LED) lighting device and more particularly, to an LED lighting device for a recessed can lighting system. Although embodiments of the invention are suitable for a wide scope of applications, they are particularly suitable for a light emitting diode panel in a recessed can. 
   Various lighting devices are used to illuminate interior spaces. These include candelabras, chandeliers, track lighting and recessed cans. The latter are used when the lighting devices are to be hidden from view and otherwise unobtrusive. Most commonly, incandescent lighting is used in recessed cans. 
   A recent trend in interior lighting is to replace incandescent bulbs with fluorescent bulbs. Fluorescent bulbs are advantageous over incandescent bulbs primarily because of their greater longevity and higher efficiency. In many cases, fluorescent bulbs can increase operating efficiencies several-fold without substantially sacrificing brightness, lighting quality or color. Fluorescent bulbs are used in recessed lighting devices as well with the same advantages. 
   Interior lighting based on the use of light emitting diode (LED) technology is still relatively new. Light emitting diode technology provides lighting capabilities at far greater efficiency than are even provided by fluorescent bulbs. Recent improvements have raised the brightness and lighting quality of light emitting diode light fixtures up to the standards of incandescent bulbs. However, light emitting diodes in the light emitting diode lighting panels used in lighting devices of various types are susceptible to overheating. When overheating occurs, the efficiency and lifetime of the light emitting diodes is decreased. In some cases, overheating may lead to either catastrophic failure in the LEDs and/or create safety hazards. 
   SUMMARY OF THE INVENTION 
   Accordingly, embodiments of the invention are directed to an LED lighting device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
   An object of embodiments of the invention is to provide an LED lighting device with light emitting diodes arranged at the periphery of the LED lighting device. 
   Another object of embodiments of the invention is to provide an LED lighting device with a flexible attachment piece that attaches the LED lighting device to a power supply. 
   Another object of embodiments of the invention is to provide an LED lighting device for insertion into a can wherein the light emitting diode panel of the LED lighting device is positioned outside of the can when the LED lighting device has been inserted into a recessed can. 
   Additional features and advantages of embodiments of the invention will be set forth in the description which follows, and in part will be apparent from the description, or is learned by practice of embodiments of the invention. The objectives and other advantages of the embodiments of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, the lighting device includes: a light emitting diode lighting panel having first and second opposing surfaces; light emitting diodes at a periphery of light emitting diode lighting panel for emitting light through the first surface; a reflective surface at the second surface of the light emitting diode lighting panel; and a power supply unit connected to the light emitting diode panel, the power supply having first and second ends, and electrical circuitry for converting alternating current to direct current between the first and second ends, wherein the first end is for insertion into the a socket. 
   In another aspect, the lighting device includes: a light emitting diode lighting panel having first and second opposing surfaces; light emitting diodes arranged at a periphery of the light emitting diode lighting panel for emitting light through the first surface; a reflective surface on the second surface of the light emitting diode lighting panel; a power supply unit for the light emitting diode panel containing electrical circuitry for converting alternating current to direct current, and the power supply unit having first and second ends; and a flexible attachment piece attached to the second end of the power supply for redirecting the light emitting diode lighting panel. 
   In another aspect, the lighting device includes: a light emitting diode lighting panel having first and second opposing surfaces; light emitting diodes arranged at a periphery of the first surface of the light emitting diode lighting panel for emitting light through the first surface; a reflective surface on the second surface of the light emitting diode lighting panel; and a power supply unit for the light emitting diode panel containing electrical circuitry to convert alternating current to direct current, and the power supply unit having first and second ends, wherein: the first end of the power supply has a first cross-sectional width and fits into a socket for one of an incandescent and fluorescent light bulb, and the light emitting diode panel has a second width greater than four times the first cross-sectional width of the first end of the power supply. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of embodiments of the invention as claimed. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of embodiments of the invention. 
       FIG. 1   a  shows a bottom view of a circular LED panel light; 
       FIG. 1   b  shows a side view of the circular LED panel light of  FIG. 1   a;    
       FIG. 1   c  shows a side view of the circular LED panel light of  FIG. 1   a  with a lens; 
       FIG. 2   a  shows the assembly of a circular LED panel of  FIG. 1   a  and a power supply; 
       FIG. 2   b  shows an assembled view of the circular LED panel and power supply of  FIG. 2   a;    
       FIG. 3   a  shows the assembly of the circular LED panel of  FIG. 1   a  and a power supply with a flexible attachment piece; 
       FIG. 3   b  shows an assembled view of the circular LED panel and power supply of  FIG. 3   a;    
       FIG. 3   c  shows clockwise redirection of the assembled circular LED panel and power supply of  FIG. 3   a;    
       FIG. 3   d  shows counter clockwise redirection of the assembled circular LED panel and power supply of  FIG. 3   a;    
       FIG. 4   a  shows the assembly of an oversized circular LED panel and a power supply for a recessed lighting can; 
       FIG. 4   b  shows an assembled view of the oversized circular LED panel, power supply and for a recessed lighting can of  FIG. 4   a;    
       FIG. 5   a  shows the assembly of an oversized, convex circular LED panel and a power supply; 
       FIG. 5   b  shows an assembled view of the oversized, convex circular LED panel and power supply of  FIG. 5   a;    
       FIG. 6  shows an assembled view of an oversized circular LED panel and power supply with a flexible attachment piece; 
       FIG. 7   a  shows a front and a side view of a first step in the assembly of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply; 
       FIG. 7   b  shows a front and a side view of a second step in the assembly of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply; 
       FIG. 7   c  shows a front and a side view of a third step in the assembly of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply; 
       FIG. 8   a  shows a first step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; 
       FIG. 8   b  shows a second step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; 
       FIG. 8   c  shows a third step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; 
       FIG. 8   d  shows a fourth step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; 
       FIG. 8   e  shows a fifth step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; 
       FIG. 8   f  shows a sixth step in the installation and an example height adjustment of an adjustable height circular LED panel light and power supply; and 
       FIG. 9  shows a comparison between two different settings of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply. 
   


   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. It will be apparent to those skilled in the art that various modifications and variations is made in the embodiments of the invention, the recessed can lighting device, without departing from its spirit or scope. Thus, it is intended that embodiments of the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals in the drawings denote like elements. 
   Installation of light emitting diode panels in recessed lighting devices typically requires for either redesign and modification of existing fixtures or the design of entirely new fixtures. Thus, a recessed lighting device with a light emitting diode panel that operates in recessed lighting devices made for incandescent or fluorescent bulbs without excessive modification to the fixtures is an easier alternative. A recessed lighting device having a light emitting diode panel that allows sufficient ventilation for the light emitting diodes of the panel and the circuitry that regulates the power delivered to the light emitting diodes extends the operational life of the light emitting diode. 
     FIG. 1   a  shows a bottom view of a circular LED panel light.  FIG. 1   b  shows a side view of the circular LED panel light of  FIG. 1   a . The circular LED panel  10  is circular or disk shaped, as shown in  FIG. 1   a , or is one of a number of other shapes, such as that of an ellipse, polygon or annulus and has a top surface  10   a . The circular LED panel  10  of  FIG. 1   a  is created by wrapping a disk-shaped light guide panel  2  with a strip  10   b  of light emitting diodes  1 . Alternatively, the circular LED panel  10  and light emitting diodes  1  may be one monolithic piece (not shown). 
   The light guide panel  2  is made from one of transparent and partially transparent polymers. As shown in  FIG. 1   a  and  FIG. 1   b , the light emitting diodes  1  emit light L 1  that enters the light guide panel  2  at its edge  2   a  in a radially inward direction. 
   As shown in  FIG. 1   b , a top surface  10   a  of the circular LED panel  10  has a mirrored edge  3  that reflects light L 1  emitted by the light emitting diodes  1  of the circular LED panel  10 . The mirrored edge  3  is a metallic or reflective layer that is separate from the light guide panel  2 . Alternatively, the mirrored edge  3  is a coating of the light guide panel  2  with a reflective material such as a metal. The mirrored edge  3  is completely opaque and reflective to the light L emitted by the light emitting diodes  1 . Alternatively, the mirrored edge  3  is partially transmissive and partially reflective to the light L 1  emitted by the light emitting diodes  1 . As shown in  FIG. 1   b , light L 1  emitted by the light emitting diodes  1  is reflected from the mirrored edge  3  leaves the circular LED panel  10  through the bottom surface  10   b  of the circular LED panel  10  to provide light L 2  below the circular LED panel  10 . 
   As shown in  FIG. 1   b , the circular LED panel  10  has connectors  4  and  5  for connecting the circular LED panel  10  to a power source (not shown). The circular LED panel  10  may have two connectors  4  and  5 , as shown in  FIG. 1   b , or it may have one, three or more connectors. The connectors  4  and  5  of the circular LED panel  10  are connected to the circular LED panel  10  via a flexible wire as shown in  FIG. 1   b , or the connectors  4  and  5  of the circular LED panel  10  are connected to the circular LED panel  10  via another type of interconnection, such as an inflexible wire, flexible or inflexible ribbon, flexible or inflexible post (not shown). As shown in  FIG. 1   b , the circular LED panel  10  may also have a lip  6  for snap attaching the circular LED panel  10  to another device. 
     FIG. 1   c  shows a side view of the circular LED panel of  FIG. 1   a  with a lens. The lens  7  disperses the light L 2  exiting the circular LED panel  10  as it exits the circular LED panel through the bottom surface  10   b  of the circular LED panel  10 . The lens  7  distributes the light L 2  emitted by the circular LED panel  10  to light interior spaces more efficiently. In the alternative, the lens  7  also includes reflective surfaces to increase the refraction of redirected light, or to redirect light to specific targets. In another alternative, the lens  7  has more than one lens for both focusing and dispersion of the light created by the circular LED panel  10 . In yet another alternative, the lens  7  further includes one or several optical elements (not shown), such as light guide panels, convex or concave lenses, filters, parabolic, flat mirrors, shaped-mirrors, polarizers or light blocking devices (not shown). 
     FIG. 2   a  shows the assembly of a circular LED panel of  FIG. 1   a  and a power supply.  FIG. 2   b  shows an assembled view of the circular LED panel and power supply of  FIG. 2   a . The power supply  20  has an input end  22 , a main body  30  and output end  24  having connectors  25  and  26 . As shown in  FIG. 2   a , the power supply  20  has an input end  22  for insertion into a socket, (not shown) which also accepts a fluorescent or an incandescent light bulb. Alternatively, the input end  22  of the power supply  20  may contain wires or connectors (not shown) enabling it to connect directly to a power line. Alternatively, the input end  22  of the power supply  20  may contain one of a number of other types of connectors, such as alligator clips, pins or snap fasteners (not shown), that enable the power supply  20  to draw power from external sources such as an outlet or a main power line. 
   The main body  31  of the power supply  30  contains an AC/DC converter  23 , a transformer (not shown) and other power conversion devices (not shown). The AC/DC converter  23  is one of a number of different circuits including a diode bridge, bridge rectifier, as shown in  FIG. 2   a , or other power control circuitry. The AC/DC converter  23  may also contain other elements and circuits (not shown) for power regulation, heat dissipation or other uses. 
   The connectors  4  and  5  of the circular LED panel  10  and the connectors  25  and  26  of the power supply  20  are reversibly connectable, as shown in  FIG. 2   a . Alternatively, the connectors  4  and  5  of the circular LED panel  10  and the connectors  25  and  26  of the power supply  20  are permanently connected. The connectors  4  and  5  of the circular LED panel  10  and the connectors  25  and  26  of the power supply  20  are reversibly connectable using a plug and a socket, as shown in  FIG. 2   a , or pins and sockets, tabs and slits and other types of reversible connectors (not shown). The connectors  25  and  26  of the power supply  20  are connected to the power supply  20  via a flexible wire as shown in  FIG. 2   a , or in the alternative, the connectors  25  and  26  of the power supply  20  are connected to the power supply  20  via another type of interconnection, such as an inflexible wire, flexible or inflexible ribbon, flexible or inflexible post (not shown). 
   Because the connectors  4  and  5  of the circular LED panel  10  and the connector  25  and  26  of the power supply  20  are reversibly connectable, either component is independently replaceable. In particular, disconnecting the connectors  25  and  26  from the connectors  4  and  5  allows one of the circular LED panel  10  and the power supply  20  to be removed without having to remove the other component. This is useful since the lifetimes of the circular LED panel  10  and the power supply  20  differ so as to result in the need to replace one of these components more often than the other. For example, the electronics associated with the power supply  20  could be more prone to overheating and subject to short circuiting and burn-out. Reversibility of the connectors  25  and  26  from the connectors  4  and  5  allows the replacement of either the circular LED panel  10  or the power supply  20  as needed. Additionally, the reversibility of connectors  25  and  26  from the connectors  4  and  5  allows quick removal and repair of either the power supply  20  or the circular LED panel  10 . 
   As shown in  FIG. 2   b , assembling the circular LED panel  10  to the power supply  20  hides the connectors  4 ,  5 ,  25  and  26  from view by covering them with the exterior of the power supply  20 . Alternatively, the connectors  4 ,  5 ,  25  and  26  are exposed after the circular LED panel  10  has been assembled to the power supply  20  or the connectors  4 ,  5 ,  25  and  26  fit in a depression or recessed portion (not shown) of the circular LED panel  10 . 
   As shown in  FIGS. 2   a  and  2   b , the circular LED panel  10  also has a lip  6  and the power supply  20  has a corresponding lip receiving portion  27  both of which are used to attach the circular LED panel  10  to the power supply  20 . As shown in  FIG. 2   a , in assembly the circular LED panel  10  is attached to the power supply  20  by placing the lip  6  of the circular LED panel  10  inside the lip receiving portion  27  of the power supply  20 . Upon assembly, as shown in  FIG. 2   b , the lip  6  of the circular LED panel  10  is contained within the lip accepting portion  27  of the power supply  20 . The lip  6  of the circular LED panel  10  may snap-fasten to the lip receiving portion  27  of the power supply  20 . Alternatively, the lip  6  of the circular LED panel  10  and the lip receiving portion  27  of the power supply  20  may be threaded (not shown) such that the lip  6  and the lip receiving portion  27  are placed into contact and rotated until the circular LED panel  10  is attached to the power supply  20 . Alternatively, the circular LED panel  10  is attached to the power supply  20  by one of a number of other methods that include pins, pinch pins, clasps, tabs, bolts or other attaching mechanisms (not shown). 
     FIG. 3   a  shows the assembly of the circular LED panel of  FIG. 1   a  and a power supply with a flexible attachment piece.  FIG. 3   b  shows an assembled view of the circular LED panel and power supply of  FIG. 3   a.    
   The power supply  30  has an input end  32 , a main body  31  and an output end  33  having connectors  34  and  35  extending through a flexible attachment piece  36 . As shown in  FIG. 3   a , the power supply  30  has a main body portion  31  that is attached to an end  32 . The end  32  of the power supply  30  for insertion into a socket (not shown) that also accepts a fluorescent or an incandescent light bulb. Alternatively, the end  32  of the power supply  30  can contain wires or connectors (not shown) enabling it to connect directly to a power line. In another alternative, the end  32  of the power supply  30  contains one of a number of other connectors, such as alligator clips, pins or snap fasteners (not shown), that enable the power supply  30  to draw power from external sources, such as an outlet or a main power line. 
   The main body  31  of the power supply  30  contains an AC/DC converter (not shown), a transformer (not shown) and other power conversion devices (not shown). The AC/DC converter is one of a number of different circuits including a diode bridge, bridge rectifier or other types of power control circuitry. The AC/DC converter may also contain other elements and circuits (not shown) for power regulation, heat dissipation or other uses. 
   The connectors  4  and  5  of the circular LED panel  10  and the connectors  34  and  35  of the power supply  30  are reversibly connectable, as shown in  FIG. 3   a . Alternatively, the connectors  4  and  5  of the circular LED panel  10  and the connectors  34  and  35  of the power supply  30  are permanently connected. The connectors  4  and  5  of the circular LED panel  10  and the connectors  34  and  35  of the power supply  30  are reversibly connectable using a plug and a socket, as shown in  FIG. 3   a , or pins and sockets, tabs and slits and other types of reversible connectors (not shown). The connectors  34  and  35  of the power supply  30  are connected to the power supply  30  via a flexible wire as shown in  FIG. 3   a , or in the alternative, the connectors  34  and  35  of the power supply  30  are connected to the power supply  30  via another type of interconnection, such as an inflexible wire, flexible or inflexible ribbon, flexible or inflexible post (not shown). 
   Because the connectors  4  and  5  of the circular LED panel  10  and the connector  34  and  35  of the power supply  30  are reversibly connectable, either component is independently replaceable. In particular, disconnecting the connectors  34  and  35  from the connectors  4  and  5  allows one of the circular LED panel  10  and the power supply  30  to be removed without having to remove the other component. This is useful since the lifetimes of the circular LED panel  10  and the power supply  20  differ so as to result in the need to replace one of these components more often than the other. For example, the electronics associated with the power supply  30  could be more prone to overheating and subject to short circuiting and burn-out. Reversibility of the connectors  34  and  35  from the connectors  4  and  5  allows the replacement of either the circular LED panel  10  or the power supply  30  as needed. Additionally, the reversibility of connectors  34  and  35  from the connectors  4  and  5  allows quick removal and repair of either the power supply  30  or the circular LED panel  10 . 
   As shown in  FIG. 3   a , the output end  33  of the power supply  30  has a flexible attachment piece  36  with a lip receiving portion  36   a  and the circular LED panel  10  has a corresponding lip  6  which are used to attach the circular LED panel  10  to the power supply  30 . As shown in  FIG. 3   b , in assembling the circular LED panel  10  to the power supply  30  the flexible attachment piece  36  is slipped over the connectors  4 ,  5 ,  34  and  35  such that the connectors  4 ,  5 ,  34  and  35  are covered by flexible attachment piece  36  and hidden from view. Alternatively, the connectors  4 ,  5 ,  34  and  35  fit in a depression or recessed portion (not shown) of the circular LED panel  10 . 
   As shown in  FIGS. 3   a  and  3   b , during assembly the circular LED panel  10  is attached to the power supply  30  by placing the lip  6  of the circular LED panel  10  inside the lip receiving portion  36   a  of the flexible attachment piece  36  of the power supply  30 . Once assembled, the lip  6  of the circular LED panel  10  is contained within the lip accepting portion  36   a  of the power supply  30 . The lip  6  of the circular LED panel  10  may snap-fasten to the lip receiving portion  36  of the power supply  20 . Alternatively, the lip  6  of the circular LED panel  10  and the lip receiving portion  36   a  of the power supply  30  may be threaded (not shown) such that the lip  6  and the lip receiving portion  36   a  are placed into contact and rotated until the circular LED panel  10  is attached to the power supply  30 . Alternatively, the circular LED panel  10  is attached to the power supply  20  by one of a number of other methods that include pins, pinch pins, clasps, tabs, bolts or other attaching mechanisms (not shown). 
     FIG. 3   c  shows clockwise redirection of the assembled circular LED panel and power supply of  FIG. 3   a .  FIG. 3   d  shows counter clockwise redirection of the assembled circular LED panel and power supply of  FIG. 3   a . The flexibility of the flexible attachment piece  36  allows the swiveling motion shown in  FIG. 3   a  and  FIG. 3   b . The bottom surface  10   b  of the circular LED panel  10  is swiveled in a CW direction shown in  FIG. 3   c  of more than 45 degrees from its position shown in  FIG. 3   b . Similarly, the bottom surface  10   b  of the circular LED panel  10  is swiveled in a CCW direction shown in  FIG. 3   d  of more than 45 degrees from its position shown in  FIG. 3   b . Swiveling along either the CW direction shown in  FIG. 3   c  or the CCW direction shown in  FIG. 3   d  allows the light L 2  emitted through the bottom surface  10   b  of the circular LED panel  10  to be redirected as needed. 
   For example, light L 2  emitted through the bottom surface  10   b  of the circular LED panel  10  that has been redirected using the flexible attachment piece  36 , as shown in  FIG. 3   c  or  FIG. 3   d , is directed to provide supplemental illumination objects on display such as paintings, sculpture or photographs. Light L 2  emitted through the bottom surface  10   b  of the circular LED panel  10  that has been redirected using the flexible attachment piece  36  can also be directed to provide supplemental illumination to fixtures such as doorways, fireplaces and footpaths. Light L 2  emitted through the bottom surface  10   b  of the circular LED panel  10  that has been redirected using the flexible attachment piece  36  can also be directed to provide supplemental illumination to a study or work area. Light L 2  emitted through the bottom surface  10   b  of a series of circular LED panels  10  and power supplies  30  may also be redirected using the flexible attachment pieces  36  associated with each power supply  30  to provide supplemental illumination as needed. 
     FIG. 4   a  shows the assembly of an oversized circular LED panel and a power supply for a recessed lighting can.  FIG. 4   b  shows an assembled view of the oversized circular LED panel, power supply and for a recessed lighting can of  FIG. 4   a . As shown in  FIG. 4   a , the width W 1  of the oversized circular LED panel  40  is larger than the width W 2  of the can  48 . The width W 2  of the oversized circular LED panel is four or more times larger than the width W 3  of the input end  22 . 
   The oversized circular LED panel  40  is circular or disk shaped, as shown in  FIG. 4   a  and  FIG. 4   b , or it may have one of a number of other shapes such as that of an ellipse, polygon or annulus. The circumference of the oversized circular LED panel  40  is lined with light emitting diodes  41   a  and  41   b  and other light emitting diodes  41  (not shown), while the interior of the oversized circular LED panel  40  contains a light guide panel  52 . The light guide panel  42  is made from of transparent and partially transparent polymers. As shown in  FIG. 4   a  and  FIG. 4   b , the light emitting diodes  41  emit light L 1  that enters the light guide panel  42  at its edge  42   a  in a radially inward direction. 
   As shown in  FIG. 4   a  and  FIG. 4   b , a top surface  40   a  of the oversized circular LED panel  40  has a mirrored edge  43  that reflects light L 1  emitted by the light emitting diodes  41   a  and  41   b , and other light emitting diodes  41  (not shown) of the oversized circular LED panel  40 . The mirrored edge  43  is a metallic or reflective layer that is separate from the light guide panel  42 . Alternatively, the mirrored edge  43  is a coating of the light guide panel  42  with a reflective material such as a metal. The mirrored edge  43  is completely opaque and reflective to the light L 1  emitted by the light emitting diodes  41   a ,  41   b  and other light emitting diodes  41  (not shown). Alternatively, the mirrored edge  3  is partially transmissive to the light L 1  emitted by the light emitting diodes  41   a  and  41   b , and other light emitting diodes  41  (not shown). As shown in  FIG. 4   a  and  FIG. 4   b , light L 1  emitted by the light emitting diodes  41   a  and  41   b , and other light emitting diodes  41  (not shown) and reflected from the mirrored edge  43  leaves the oversized circular LED panel  40  through the bottom surface  40   b  of the oversized circular LED panel  40  to provide light L 2  below the oversized circular LED panel  40 . 
   As shown in  FIG. 4   a , the oversized circular LED panel  40  has connectors  44  and  45  for connecting the oversized circular LED panel  40  to a power source. The oversized circular LED panel  40  may have two connectors  44  and  45 , as shown in  FIG. 4   a , or it may have one, three or more connectors. The connectors  44  and  45  of the oversized circular LED panel  40  are connected to the oversized circular LED panel  40  via a flexible wire as shown in  FIG. 4   a , or the connectors  4  and  5  of the oversized circular LED panel  40  are connected to the oversized circular LED panel  40  via another type of interconnection, such as an inflexible wire, flexible or inflexible ribbon, flexible or inflexible post (not shown). As shown in  FIG. 4   a , the oversized circular LED panel  40  can also have a lip  46  for snap attaching the oversized circular LED panel  40  to another device. 
   The can  48  is affixed to the ceiling  47  using one of a number of methods that include the use of affixing tabs (not shown). The can  47  is cylindrically shaped, as shown in  FIG. 4   a  and  FIG. 4   b . Alternatively, the can  47  has one of a number of different shapes including that of a rectangular prism or a prism with a triangular cross section. Alternatively, the can  47  has a spherical, semi-spherical, a shape with a circular cross section or other shape. The can  47  is made from metal, plastic or a combination thereof. The can  47  is solid and seamless. Alternatively, the can  31  can has seams, holes or ancillary cavities (not shown). 
   The can  48  includes a socket  49  for supplying power to the oversized circular LED panel  40  through the power supply  20  received into the socket  49 . The socket  49  may alternatively receive an incandescent light bulb (not shown) or a fluorescent light bulb (not shown). The power supply  20  is electrically connected to the socket  49  by inserting it into the socket  49  as shown in  FIG. 4   a  and  FIG. 4   b . The oversized circular LED panel  40  is connected to the power supply  20  by connecting the connectors  44  and  55  of the oversized circular LED panel  40  to the connectors  24  and  25  of the power supply  20 . The connectors  44  and  55  of the oversized circular LED panel  40  and the connector  24  and  25  of the power supply  20  are reversibly connectable, as shown in  FIG. 4   a . Alternatively, the connectors  44  and  55  of the oversized circular LED panel  40  and the connector  24  and  25  of the power supply  20  are permanently connected. 
   When the oversized circular LED panel  40  and power supply  20  are not installed in the can  48 , a light bulb (not shown) could be inserted into the socket  49  so as to provide electrical power to the light bulb (not shown). The socket  49  is typically either a single bulb socket, as shown in  FIG. 4   a , or is a multiple socket for multiple bulbs (not shown). In another alternative, the socket  49  has other features, such as an outlet (not shown), for supplying power to electronic devices (not shown) or additional connections, including wires (not shown), additional sockets (not shown) or pin connects (not shown). 
   The width W 1  of the oversized circular LED panel  40  is large enough to provide sufficient distance between light emitting diodes  41   a  and  41   b , and other light emitting diodes (not shown), on opposite edges of the oversized circular LED panel  40  from causing each other to overheat. In other words, the width W 1  of the oversized circular LED panel  40  is large enough to prevent convection or thermal radiation from light emitting diodes  41   a  and  41   b  on opposite edges of the oversized circular LED panel  40  from reaching each other. Keeping the light emitting diodes  41   a  and  41   b  on opposite edges of the oversized circular LED panel  40  relatively cool increases the lifetime of each of the light emitting diodes  41   a ,  41   b  and other light emitting diodes  41  (not shown) of the oversized circular LED panel  40 . Further, the width W 1  of the oversized circular LED panel  40  is large enough to prevent convection or thermal radiation from light emitting diodes  41  from entering the interior  48   a  of the can  48 . 
   Ventilation from the air passages  47   a  between the oversized circular LED panel  40  and the ceiling  47  cools the light emitting diodes  41   a ,  41   b  and other light emitting diodes  41  (not shown) and keeps the heat given off by the light emitting diodes  41   a ,  41   b  and other light emitting diodes  41  (not shown) from affecting the power supply  20 . Both the oversized circular LED panel  40  and the power supply  20  can heat, during normal operation, to temperatures that could degrade the operating efficiency or the lifetime of the power supply  20  and oversized circular LED panel  40 . Cooling due to ventilation created by air passages  47   a  prolongs the lifetime of the power supply  20  and the oversized circular LED panel  40 . 
     FIG. 5   a  shows the assembly of an oversized convex circular LED panel and a power supply.  FIG. 5   b  shows an assembled view of the oversized convex circular LED panel and power supply of  FIG. 5   a.    
   The oversized convex circular LED panel  50  is circular or disk shaped, as shown in  FIG. 5   a  and  FIG. 5   b , or it may have one of a number of other shapes, such as that of an ellipse, polygon or annulus. The circumference of the oversized convex circular LED panel  50  is lined with light emitting diodes  51   a ,  51   b  and other light emitting diodes  51  (not shown) while the interior of the oversized convex circular LED panel  50  contains a light guide panel  52 . The light guide panel  52  is made from of transparent and partially transparent polymers. As shown in  FIG. 5   a  and  FIG. 5   b , the light emitting diodes  51   a ,  51   b  and other light emitting diodes  51  (not shown) emit light L 1  that enters the light guide panel  52  at its edge  52   a  in a radially inward direction. 
   As shown in  FIG. 5   a  and  FIG. 5   b , a top surface  50   a  of the oversized convex circular LED panel  50  has a mirrored edge  53  that reflects light L emitted by the light emitting diodes  51   a  and  51   b , and other light emitting diodes  51  (not shown) of the oversized convex circular LED panel  50 . The mirrored edge  53  is a metallic or reflective layer that is separate from the light guide panel  52 . Alternatively, the mirrored edge  53  is a coating of the light guide panel  52  with a reflective material, such as a metal. The mirrored edge  53  is completely opaque and reflective to the light L emitted by the light emitting diodes  51   a  and  51   b , and other light emitting diodes  51  (not shown). Alternatively, the mirrored edge  53  is partially transmissive to the light L emitted by the light emitting diodes  51   a ,  51   b  and other light emitting diodes  51  (not shown). As shown in  FIG. 5   a  and  FIG. 5   b , light L 1  emitted by the light emitting diodes  51   a  and  51   b , and other light emitting diodes  51  (not shown) and reflected from the mirrored edge  53  leaves the oversized convex circular LED panel  50  through the bottom surface  50   b  of the oversized convex circular LED panel  50  to provide light L 2  below the oversized convex circular LED panel  50 . 
   As shown in  FIG. 5   a , the bottom edge  50   b  of the oversized convex circular LED panel  50  has a convex shape. The convex shape of the bottom edge  50   b  of the oversized convex circular LED panel  50  tends to cause dispersion of the light L 2  exiting the oversized convex circular LED panel  50  from the bottom edge  50   b , as shown in  FIG. 5   b . Dispersing the light L 2  exiting the bottom edge  50   b  of the oversized convex circular LED panel  50 , as shown in  FIG. 5   a  and  FIG. 5   b , provides more diffuse and pleasant lighting. Further, using the oversized convex circular LED panel  50  provides more even lighting to larger spaces, such as rooms or entry ways. In addition, the oversized convex circular LED panel  50  has a lighting effect closer to that of an incandescent bulb. 
   As shown in  FIG. 5   a , the oversized convex circular LED panel  50  has connectors  54  and  55  for connecting the oversized convex circular LED panel  50  to a power source. The oversized convex circular LED panel  50  may have two connectors  54  and  55 , as shown in  FIG. 5   a , or it may have one, three or more connectors. The connectors  54  and  55  of the oversized convex circular LED panel  50  are connected to the oversized convex circular LED panel  50  via a flexible wire as shown in  FIG. 5   a , or the connectors  4  and  5  of the oversized convex circular LED panel  50  are connected to the oversized convex circular LED panel  50  via another type of interconnection, such as an inflexible wire, flexible or inflexible ribbon, flexible or inflexible post (not shown). As shown in  FIG. 5   a , the oversized convex circular LED panel  50  may also have a lip  56  for snap attaching the oversized convex circular LED panel  50  to another device. 
   The can  48  is affixed to the ceiling  47  using one of a number of methods that include the use of affixing tabs (not shown). The can  47  is cylindrically shaped, as shown in  FIG. 5   a  and  FIG. 5   b . Alternatively, the can  47  has one of a number of different shapes including that of a rectangular prism or a prism with a triangular cross section. Alternatively, the can  47  has a spherical, semi-spherical, a shape with a circular cross section or other shape. The can  47  is made from metal, plastic or a combination thereof. The can  47  is solid and seamless. Alternatively, the can  31  can has seams, holes or ancillary cavities (not shown). 
   The can  48  includes a socket  49  for supplying power to the oversized convex circular LED panel  50  through the power supply  20 . The socket  49  may alternatively receive an incandescent light bulb (not shown) or a fluorescent light bulb (not shown). The power supply  20  is electrically connected to the socket  49  by inserting it into the socket  49  as shown in  FIG. 5   a  and  FIG. 5   b . The oversized convex circular LED panel  50  is connected to the power supply  20  by connecting the connectors  54  and  55  of the oversized convex circular LED panel  50  to the connectors  24  and  25  of the power supply  20 . The connectors  44  and  55  of the oversized convex circular LED panel  50  and the connector  24  and  25  of the power supply  20  are reversibly connectable, as shown in  FIG. 5   a . Alternatively, the connectors  44  and  55  of the oversized convex circular LED panel  50  and the connector  24  and  25  of the power supply  20  are permanently connected. 
   When the oversized convex circular LED panel  50  and power supply  20  are not installed in the can  48 , a light bulb (not shown) could be inserted into the socket  49  so as to provide electrical power to the light bulb (not shown). The socket  49  is typically either a single bulb socket, as shown in  FIG. 5   a , or is a multiple socket for multiple bulbs (not shown). In another alternative, the socket  49  has other features such as an outlet (not shown) for supplying power to electronic devices (not shown) or additional connections including wires (not shown), additional sockets (not shown) or pin connects (not shown). 
   As shown in  FIG. 5   a , the width W 1  of the oversized convex circular LED panel  50  is larger than the width W 2  of the can  48 . The width W 1  of the oversized convex circular LED panel  50  is large enough to provide sufficient distance between light emitting diodes  51   a  and  51   b , and other light emitting diodes  51  (not shown), on opposite edges of the oversized convex circular LED panel  50  from causing each other to overheat. In other words, the width W 1  of the oversized convex circular LED panel  50  is large enough to prevent convection or thermal radiation from light emitting diodes  51   a  and  51   b , and other light emitting diodes  51  (not shown), on opposite edges of the oversized convex circular LED panel  50  from reaching each other. Keeping the light emitting diodes  51   a  and  51   b , other light emitting diodes  51  (not shown), on opposite edges of the oversized convex circular LED panel  50  relatively cool increases the lifetime of each light emitting diodes  51   a ,  51   b  and other light emitting diodes  51  (not shown) of the oversized convex circular LED panel  50 . Further, the width W 1  of the oversized convex circular LED panel  50  is large enough to prevent convection or thermal radiation from light emitting diodes  51  from entering the interior  48   a  of the can  48 . 
   Ventilation from the air passages  47   a  between the oversized convex circular LED panel  50  and the ceiling  47  cools the light emitting diodes  51  and keeps the heat given off by the light emitting diodes  51  from affecting the power supply  20 . Both the oversized convex circular LED panel  50  and the power supply  20  can heat, during normal operation, to temperatures that could degrade the operating efficiency or the lifetime of the power supply  20  and oversized convex circular LED panel  50 . Cooling due to ventilation created by air passages  47   a  prolongs the lifetime of the power supply  20  and the oversized convex circular LED panel  50 . 
     FIG. 6  shows an assembled view of an oversized circular LED panel and power supply with a flexible attachment piece. The can  61  is affixed to the ceiling  47  using one of a number of methods that include the use of affixing tabs (not shown). The can  61  is cylindrically shaped, as shown in  FIG. 6 . Alternatively, the can  61  has one of a number of different shapes including that of a rectangular prism or a prism with a triangular cross section. Alternatively, the can  61  has a spherical, semi-spherical, a shape with a circular cross section or other shape. The can  61  is made from metal, plastic or a combination thereof. The can  61  is solid and seamless. Alternatively, the can  61  may have seams, holes or ancillary cavities (not shown). 
   The can  61  includes a socket  63  for supplying power to the oversized circular LED panel  60  through the power supply  30  received into the socket  63 . The socket  63  may alternatively receive an incandescent light bulb (not shown) or a fluorescent light bulb (not shown). The power supply  30  is electrically connected to the socket  63  by inserting the input end  32  of the power supply  30  into the socket  63  as shown in  FIG. 6 . The oversized circular LED panel  40  is connected to the power supply  30  by connecting the connectors  44  and  45 , shown in  FIG. 4   a , of the oversized circular LED panel  40  to the connectors  34  and  35 , shown in  FIG. 3   a , of the power supply  30 . The connectors  44  and  45  of the oversized circular LED panel  40  and the connectors  34  and  35  of the power supply  30  are reversibly connectable. Alternatively, the connectors  44  and  45  of the oversized circular LED panel  40  and the connector  34  and  35  of the power supply  30  are permanently connected. Wires  64  connect the socket  63  to an external circuit. 
   Ventilation from the air passages  47   a  between the oversized circular LED panel  60  and the ceiling  47  cools the light emitting diodes  61 , and keeps the heat given off by the light emitting diodes  61  from affecting the power supply  30 . Both the oversized circular LED panel  60  and the power supply  30  can heat, during normal operation, to temperatures that could degrade the operating efficiency or the lifetime of the power supply  30  and oversized circular LED panel  60 . Cooling due to ventilation created by air passages  47   a  prolongs the lifetime of the power supply  30  and the oversized circular LED panel  60 . 
   As shown in  FIG. 6 , the power supply  30  also has a flexible attachment piece  36  that is attached to the oversized circular LED panel  60 . In assembling the oversized circular LED panel  60  to the power supply  30 , the flexible attachment piece  36  is slipped over the connectors  44 ,  45 ,  34  and  35  such that the connectors  44 ,  45 ,  34  and  35  are covered by flexible attachment piece  36  and hidden from view. Alternatively, the connectors  44 ,  45 ,  34  and  35  fit in a depression or recessed portion (not shown) of the oversized circular LED panel  60 . 
   When the oversized circular LED panel  60  and power supply  30  are not installed in the can  61 , a light bulb (not shown) could be inserted into the socket  63  so as to provide electrical power to the light bulb (not shown). The socket  63  is typically either a single bulb socket, as shown in  FIG. 6 , or is a multiple socket for multiple bulbs (not shown). In another alternative, the socket  63  has other features, such as an outlet (not shown), for supplying power to electronic devices (not shown) or additional connections, including wires (not shown), additional sockets (not shown) or pin connects (not shown). 
   The springs  62   a  and  62   b  allow the oversized circular LED panel  60  to be temporarily displaced from the can  61  in a direction away from the socket  63 , when the oversized circular LED panel  60  is pulled in that direction by the user. Once the user ceases to pull on the oversized circular LED panel  60 , the springs  62   a  and  62   b  cause the oversized circular LED panel  60  to return to the original configuration shown in  FIG. 6 . The displacement of the oversized circular LED panel  60  from the can  61  allowed by the spring enables the removal and replacement of the oversized circular LED panel  60  and the replacement of the power supply  30 . Typically, the oversized circular LED panel  60  covers the bottom edge  61   b  of the can  61 , as shown in  FIG. 6 . Alternatively, portions of the oversized circular LED panel  60  do not cover some portions of the bottom edge  61   b  of the can  61 . 
   When the can  61  is fixed in place with the springs  62   a  and  62   b , light L 2  from the oversized circular LED panel  60  the flexible attachment piece  36  is in the un-extended position shown in  FIG. 6 . In this case, light L 2  from the oversized circular LED panel  60  is directed downward. However, when the springs  62   a  and  62   b  are removed from the oversized circular LED panel  60 , the oversized circular LED panel  60  with the flexible attachment piece  36  is released. In this case, the flexible attachment piece  36  may be adjusted (as illustrated in  FIGS. 3   c  and  3   d ) to redirect the light L 2  from the oversized circular LED panel  60  as needed. 
     FIGS. 7   a - 7   c  show front and side views of steps in the assembly of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply. As shown in  FIG. 7   a , the adjustable height circular LED panel light  70  includes light emitting diodes  71   a  placed around its circumference in the same manner as the circular LED panel light  10  of  FIGS. 1   a - 1   c . Unlike the circular LED panel light  10  of  FIGS. 1   a - 1   c , however, the adjustable height circular LED panel light  70  includes a post  70   b  with a knob  70   c  for insertion into the adjustable height circular LED panel light accepting power supply  76 . The adjustable height circular LED panel light  70  has a connector  74  that is inserted into a corresponding connector  77  in the adjustable height circular LED panel light accepting power supply  76  for supplying power to the light emitting diodes  71   a.    
   As shown in  FIG. 7   a , the adjustable height circular LED panel light accepting power supply  76  has an input end  76   a  for insertion into a socket, (not shown). As also shown in  FIG. 7   a , the adjustable height circular LED panel light accepting power supply  76  has a knob accepting groove  78  that accepts the knob  70   c . The knob accepting groove  78  of the adjustable height circular LED panel light accepting power supply  76  contains several rest positions  78   a - 78   d  for holding the knob  70   c . Although four rest positions  78   a - 78   d  are shown in  FIGS. 7   a - 7   c , there may be two, three, four or more rest positions. The adjustable height circular LED panel light accepting power supply  76  also has a post accepting hole  76   b  for accepting the post  70   b  of the adjustable height circular LED panel light  70 . As illustrated in the side view of  FIG. 7   a , the post accepting hole  76   b  and the rest positions  78   a - 78   d  are connected and form one continuous hole in the interior of the adjustable height circular LED panel light accepting power supply  76 . 
   In the first step in the assembly of an adjustable height circular LED panel light  70  to an adjustable height circular LED panel light accepting power supply  76 , the connector  74  of the adjustable height circular LED panel light  70  is inserted into the corresponding connector  77  in the adjustable height circular LED panel light accepting power supply  76  (insertion not shown). Then, as shown in  FIG. 7   a , the post  70   b  of the adjustable height circular LED panel light  70  is inserted into the post accepting hole  76   b  of the adjustable height circular LED panel light accepting power supply  76 . Simultaneously, the knob  70   c  of the adjustable height circular LED panel light  70  is slid into the knob accepting groove  78  of the adjustable height circular LED panel light accepting power supply  76 , as shown in the Front View of  FIG. 7   a.    
   The adjustable height circular LED panel light  70  is pushed upward, as shown in  FIG. 7   a , until the knob  70   c  is parallel with the rest position  78   a - 78   d  corresponding to the desired height of the adjustable height circular LED panel light  70 .  FIG. 7   b  shows the knob  70   c  parallel with the rest position  78   c . Once the knob  70   c  is parallel to the desired rest position, one of the adjustable height circular LED panel light  70  and the adjustable height circular LED panel light accepting power supply  76  is rotated relative to other, as shown in  FIG. 7   b , until the knob is located within the desired rest position,  78   c . Then, as shown in  FIG. 7   c , the knob  70   c  is fixed in the desired rest position  78   c  by displacing the adjustable height circular LED panel light  70  downward slightly with respect to the adjustable height circular LED panel light accepting power supply  76 . This locks in the desired height of the adjustable height circular LED panel light  70  corresponding to the desired rest position  78   c , as shown in  FIG. 7   c.    
     FIGS. 8   a - 8   f  show steps in the installation and example height adjustment of an adjustable height circular LED panel light and power supply. As shown in  FIG. 8   a , the adjustable height circular LED panel light  70  and adjustable height circular LED panel light accepting power supply  76 , after being assembled as shown in  FIGS. 7   a - 7   c , are partially inserted into the interior  48   a  of the can  48 . Then, as shown in  FIG. 8   b , the input end  76   a  of the adjustable height circular LED panel light accepting power supply  76  is placed into the socket  49  and screwed so as to tighten the connection between the input end  76   a  of the adjustable height circular LED panel light accepting power supply  76  and the socket  49 . 
   If a height readjustment is desired, the adjustable height circular LED panel light  70  is displaced upward and rotated with respect to the adjustable height circular LED panel light accepting power supply  76 , as shown in  FIG. 8   c . The upward displacement and rotation shown in  FIG. 8   c , unlocks the knob  70   c  from the rest position  78   c  and moves the knob  70   c  to vertical portion  78   e  of the knob accepting groove  78 . The knob  70   c  is shown in the vertical portion  78   e  of the knob accepting groove  78  in  FIG. 8   d . Subsequently, while the knob  70   c  remains in the vertical portion  78   e  of the knob accepting groove  78 , the adjustable height circular LED panel light  70  is displaced either upward or downward with respect to the adjustable height circular LED panel light accepting power supply  76  so as to reposition the knob  70   c  and adjust the height of the adjustable height circular LED panel light  70 . For example,  FIG. 8   d  shows displacing the adjustable height circular LED panel light  70  upwardly to increase the height of the adjustable height circular LED panel light  70  relative to the ceiling  47 . In the example, the knob  70   c  is adjusted to the desired height of rest position  78   a , as shown in  FIG. 8   e.    
   Then, the adjustable height circular LED panel light  70  is rotated as shown in  FIG. 8   e . The rotation shown in  FIG. 8   e  brings the knob  70   c  to the rest position  78   a . Subsequently, the adjustable height circular LED panel light  70  is displaced downward, as shown in  FIG. 8   f , and the knob  70   c  is locked into place in the desired rest position  78   a . Displacing the adjustable height circular LED panel light  70  downward also locks the height adjustment of the adjustable height circular LED panel light  70 , as shown in  FIG. 8   f.    
     FIG. 9  shows a comparison between two different settings of an adjustable height circular LED panel light to an adjustable height circular LED panel light accepting power supply.  FIG. 9  shows an adjustable height circular LED panel light  90  with its knob  90   c  set in the rest position  98   a  of the corresponding adjustable height circular LED panel light accepting power supply  96 .  FIG. 9  also shows another adjustable height circular LED panel light  100  with its knob  100   c  set in the rest position  108   d  of the corresponding adjustable height circular LED panel light accepting power supply  106 . ΔH, as further shown in  FIG. 9 , is the height difference between adjustable height circular LED panel lights  90  and  100  as a result of the different positions of knobs  90   c  and  100   c , respectively. 
   It will be apparent to those skilled in the art that various modifications and variations is made in the recessed can lighting device of embodiments of the invention without departing from the spirit or scope of the invention. Thus, it is intended that embodiments of the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
A lighting device comprising: a light emitting diode lighting panel having first and second opposing surfaces; light emitting diodes at a periphery of light emitting diode lighting panel for emitting light through the first surface; a reflective surface at the second surface of the light emitting diode lighting panel; and a power supply unit connected to the light emitting diode panel, the power supply having first and second ends, and electrical circuitry for converting alternating current to direct current between the first and second ends, wherein the first end is for insertion into the a socket.