Abstract:
Disclosed is a light emitting diode bulb having a base member having a first surface and a second surface, an electrical connector at the first surface of the base member, a plurality of light emitting diode modules stacked on the second surface and along an axis line, a region defined by two radii extending from the axis and an outer periphery of the plurality of light emitting diodes modules, and a plurality of side-emitting light emitting diodes on each of the plurality of light emitting diode modules wherein the plurality of side-emitting light emitting diodes is within the region.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The embodiments of the invention relate to a light emitting diode (hereinafter “LED”) bulb, and more particularly, to a LED bulb with modules having side-emitting LEDs. Although embodiments of the invention are suitable for a wide scope of applications, they are particularly suitable for lighting applications that can otherwise use compact fluorescent bulbs or incandescent bulbs. 
         [0003]    2. Discussion of the Related Art 
         [0004]    In general, the LED bulb is more energy efficient than either an incandescent bulb or a compact fluorescent bulb. An incandescent bulb converts about 3% of the supplied power into light at about 14-16 lumens/watt. A compact fluorescent bulb converts about 12% of the supplied power into light at about 60-72 lumens/watt. An LED bulb converts about 18% of the supplied power into light at about 93-95 lumens/watt. The rest of the supplied power for each of the incandescent bulb, the compact fluorescent bulb and the LED bulb is usually expended as heat. 
         [0005]    An incandescent bulb uses a filament to create light. A compact fluorescent bulb uses a gas excited by an electric field to create light. An LED bulb uses one or more LEDs in which each of the LEDs uses a semiconductor chip to create light. Because the LED bulb uses a semiconductor chip, the LED bulb can have a much longer life term than either an incandescent bulb or a compact fluorescent bulb. 
         [0006]    The light produced by traditional incandescent and florescent bulbs is largely omni-directional. Light emerges from the light source and radiates in all directions. However, in some applications, it is unnecessary to have light radiating in such a manner. Often illumination is only needed in a particular area or a single direction. For example, the purpose of a recessed ceiling light fixture is to radiate light downwards on to the objects below the fixture. There is no need to have light projected up and into the ceiling fixture. However, due to the nature of traditional bulbs, light is none the less radiated omni-directionally. Some of the energy used to create the light is wasted by unnecessarily illuminating unintended areas. 
         [0007]    Many lighting fixtures utilizing traditional bulbs are designed with reflectors which reflect light radiating in the wrong direction in a direction toward the intended area. While reflectors increase the amount of usable light from a fixture, such designs are not completely efficient and some of the light energy is lost. Additionally, because reflectors must surround the bulb, cooling of the fixture can be inhibited so as to shorten the life of the bulb. 
         [0008]    Incandescent bulbs come in different light output capabilities, different shapes, different sizes and different types of electrical connections. Although a compact fluorescent bulb is a completely different light technology than the incandescent bulb, compact fluorescent bulbs have been manufactured to have many of the same light output capacities as well as the same size, shape and screw-in type electrical connections as incandescent bulbs. Attempts have been made to achieve the same with LED bulbs but the need for heatsinks has made such previously attempted LED bulbs unsightly or unworkable. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, embodiments of the invention are directed to an LED bulb with modules having side-emitting LEDs that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
         [0010]    An object of embodiments of the invention is to provide an LED bulb that only radiates light throughout a particular angular range. 
         [0011]    Another object of embodiments of the invention is to provide an LED bulb with a light source that rotates on the base that connects to a light fixture. 
         [0012]    Another object of embodiments of the invention is to provide the number of LEDs required to achieve illumination comparable with incandescent and florescent bulbs for a predetermined area. 
         [0013]    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 may be 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. 
         [0014]    To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a light emitting diode bulb includes: a base member having a first surface and a second surface, an electrical connector at the first surface of the base member, a plurality of light emitting diode modules stacked on the second surface and along an axis line, a region defined by two radii extending from the axis and an outer periphery of the plurality of light emitting diodes modules, and a plurality of side-emitting light emitting diodes on each of the plurality of light emitting diode modules wherein the plurality of side-emitting light emitting diodes is within the region. 
         [0015]    In another aspect, the light emitting diode bulb includes: a base member having a first surface and a second surface, an electrical connector at the first surface of the base member, a pillar rotatably connected to the second surface of the base member, a plurality of light emitting diode modules stacked on the pillar, and a plurality of side-emitting light emitting diodes on each of the plurality of light emitting diode modules. 
         [0016]    In yet another aspect, a light emitting diode bulb includes: a base member having a first surface and a second surface, an electrical connector at the first surface of the base member, a pillar rotatably connected to the second surface of the base member, a plurality of light emitting diode modules connected to the pillar, a region defined by two radii extending from the pillar and an outer periphery of the plurality of light emitting diodes, and a plurality of side-emitting light emitting diodes on each of the plurality of light emitting diode modules wherein the plurality of side-emitting light emitting diodes exist in the region. 
         [0017]    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 
         [0018]    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. 
           [0019]      FIG. 1  is an assembly view of an LED bulb according to a first exemplary embodiment of the invention; 
           [0020]      FIG. 2   a  is a top view of an LED module according to an embodiment of the invention; 
           [0021]      FIG. 2   b  is a side view of the LED module in  FIG. 2   a;    
           [0022]      FIG. 2   c  is an assembly view of the LED module in  FIG. 2   b;    
           [0023]      FIG. 3   a  is a top view of a circuit board with parallel connected LEDs; 
           [0024]      FIG. 3   b  is a bottom view of a circuit board with parallel connected LEDs; 
           [0025]      FIG. 4  is a top view of an LED module having a 90° arc; 
           [0026]      FIG. 5  is a top view of an LED module having a 270° arc; 
           [0027]      FIG. 6  is a top view of an LED module having two 90° arcs; 
           [0028]      FIG. 7  is a cross-sectional view of the LED bulb of  FIG. 1  showing air flow; 
           [0029]      FIG. 8  is an isometric view of an LED bulb according to another exemplary embodiment of the invention; 
           [0030]      FIG. 9  is an isometric view of an LED bulb according to another exemplary embodiment of the invention; 
           [0031]      FIG. 10  is a side view of an LED bulb according to an exemplary embodiment of the invention in an exemplary environment; and 
           [0032]      FIG. 11  is a side view of an LED bulb according to an exemplary embodiment of the invention in an exemplary environment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals in the drawings denote like elements. 
         [0034]      FIG. 1  is an assembly view of an LED bulb according to an exemplary embodiment of the invention. As shown in  FIG. 1 , an LED bulb  100  has a base  110  with a first surface  120  and a second surface  130 . An electrical connector  125  is located on the first surface  120 . A plurality of LED modules  140  are stacked on the second surface  130 . Each of the LED modules  140  is populated with a plurality of side-emitting LEDs  150 . Heat sinks  160  are used to facilitate heat transfer from LED modules and maintain spacing between the LED module. Light diffusers  170  cover the LED modules  140  to diffuse the light from the plurality of LEDs  150 . More specifically, each of the light diffusers  170  surrounds a pair of the plurality of side-emitting LEDs  150 . In this embodiment, a pillar  135  is attached to the second surface  130 . The pillar  135  can serve as an attachment point and stabilization structure for the plurality LED modules  140 . The pillar  135  can also serve as a chimney for heat generated by the LED bulb  100  by removing heat from the heat sinks through the wall of the pillar  135 . A cap  180  secures the LED modules, diffusers, and heat sinks onto the pillar  135 . The assembled LED bulb  100  can be somewhat similar in size and shape to a typical incandescent bulb or a typical compact fluorescent bulb. 
         [0035]      FIG. 2   a  is a top view of an LED module having a 180° arc and  FIG. 2   b  is a side view of the same. As shown in  FIG. 2   a , an LED module  140  includes a circuit board  141  with electrical traces  142 , side-emitting LEDs  143  mounted on the circuit board at one end of the electrical traces  142 , and interboard connector  144  at the other end of the electrical traces  142 . 
         [0036]    The side-emitting LEDs  143  are provided in a region  145  of the LED module  140  bounded by a periphery  145  of the LED module and two radii  147   a  and  147   b  of the LED module. The side-emitting LEDs  143  can be oriented substantially radially such that the light emitted projects outwards from the center point  147   c  between the two radii  147   a  and  147   b . The side-emitting LEDs  143  can be arranged on a periphery  148  of the LED module  140 . The side-emitting LEDs  143  can be arranged on a curve so as to have an arc  146 . The angle of the arc  146  shown in  FIG. 2   a  measures 180°. 
         [0037]    Embodiments of the invention are not limited to arcs of 180°. For example, arcs of 90° and 270° are also contemplated as well as embodiments having multiple arcs. 
         [0038]    An LED module according to the above disclosed embodiment specifically provides light radiation to predefined areas. An LED module having side-emitting LEDs in a 180° arc radiates light in substantially a 180° field. Other areas beyond such a 180° field are not illuminated by the LED bulb. Selective illumination affords users of LED light bulbs lighting options and configurations not available with traditional omni-directional bulbs. Additionally, energy is saved and operating heat is reduced by only illuminating in a predefined direction. 
         [0039]    Heat generated by the side-emitting LEDs  143  can be transferred through the electrical traces  142  to the interboard connector  144 . Further, heat being transferred into the electrical traces  142  from the side-emitting LEDs can be radiated into the air by the electrical traces  142 . Furthermore, heat from the electrical traces  142  can be transferred into the heatsinks  160  through the circuit board  141 . 
         [0040]    The side-emitting LEDs  143  are electrically connected to the electrical traces  142 . The interboard connector  144  has conductors (not shown) that connect to the electrical traces  142  and run to the upper and lower surfaces of the interboard connector  144  such that direct current voltage can be supplied to the side-emitting LEDs  143  of an LED module  140  from an adjoining interboard connector or a power converter (not shown). Thus, the conductors (not shown) of the interboard connector  144  are configured such that a plurality of LED modules can be stacked upon each other and adjoining interboard connectors will provide direct current voltage to all of the side-emitting LEDs  143  in the stack of LED modules  140 . 
         [0041]    As shown in  FIG. 2   b , the interboard connector  144  extends above and below the circuit board  141  of the LED module  140 . Upon stacking a plurality of LED modules  140 , only the interboard connector  144  of each LED module  140  contacts the interboard connector  144  of another LED module  140 . Thus, the interboard connector  144  provides a spacing or gap between the circuit boards  141  and the side-emitting LEDs  143  of adjacent LED modules. 
         [0042]      FIG. 2   c  is an assembly view of the LED module shown in  FIG. 2   b . As shown in  FIG. 2   c , an interboard connector  144  can have a lower portion  144   a  and a top portion  144   b  that are joined together onto the electrical traces  142  of the circuit board  141 . By assembling the lower and upper portions  144   a  and  144   b  of the interboard connector  144  onto the circuit board  141 , the interboard connector  144  can provide spacing between LED modules  140 , power to the side-emitting LEDs  143  of the modules  140  through the electrical traces  142  and receive heat from the side-emitting LEDs  143  through the electrical traces  142 . 
         [0043]      FIG. 3   a  is a top view of a circuit board with parallel connected LEDs and  FIG. 3   b  is a bottom view of a circuit board with parallel connected LEDs. As shown in  FIG. 3   a , a circuit board  141  has an inner periphery IP and an outer periphery OP. Electrical traces  142  on the circuit board  141  have a radial pattern running from the inner periphery IP to the outer periphery OP of the circuit board  141 . The electrical traces  142  are relatively wide such that heat from the side-emitting LEDs  143  transferred into the electrical traces  142  can be radiated into the air. As shown in  FIG. 3   b , a backplane electrode  145  covers most of the side of the circuit board  141  opposite to the side having the radial electrical traces  142 . 
         [0044]    The LEDs  143  at the outer periphery of the circuit board  141  are side-emitting LEDs in that light generally emanates from the side-emitting LEDs  143  in the same radial direction as the electrical trace on which an LED is mounted. The light of the side-emitting LEDs  143  is directed outward away from the circuit board  141  such that light is not directed at another circuit board when modules including the circuit boards are stacked, as shown in  FIG. 1 . By using side-emitting LEDs  143 , which generally emit light in radial direction away from the circuit board  141 , light efficiency is improved since all light is generally emitted in direction away from the infrastructure of the LED bulb  100  when modules including the circuit boards  141  are stacked, as shown in  FIG. 1 . 
         [0045]    The side-emitting LEDs  143  are two terminal devices in which one terminal of each of the side-emitting LEDs  143  is connected one of the electrical traces  142 . The other terminal of each of the side-emitting LEDs  143  is connected to the backplane electrode  145  on the other side of the circuit board  141 , as shown in  FIG. 3   a . Because the side-emitting LEDs  143  are respectively connected to the electrical traces  142  and commonly connected to the backplane electrode  145 , the side-emitting LEDs  143  can be supplied direct current voltage in parallel to each other. An electrical failure in one LED on the circuit board  141  of parallel connected LEDs will not effect the operation of the other LEDs on the circuit board  141 . 
         [0046]    The electrical traces  142  and the backplane electrode  145  are formed of a metal or a metal alloy, such as aluminum or a copper alloy. The metal or metal alloy dissipates heat from the side-emitting LEDs  143  and transfers heat from the side-emitting LEDs  143  to the interboard connector  144 . Although the backplane electrode  145  does not directly receive heat transfer from the side-emitting LEDs  143 , the backplane electrode  145  can absorb heat through the circuit board  141  and radiate that heat into the heatsink. 
         [0047]    Heatsinks can be made from a material that is not electrically conductive to prevent electrical continuity between adjacent LED modules through the heatsink. Alternatively, a heatsink can be made from an electrically conductive material such as copper, aluminum, or steel that is then sheathed in a thin layer of thermally conductive but not electrically conductive material as mica or aluminum nitride. Heatsinks can conduct heat from the LED modules by direct contact with the LED modules. Alternatively, heatsinks and LED modules can be joined using thermal paste to increase the thermally conductive surface area. Thermal paste can contain thermally conductive ceramic compounds such as beryllium oxide, aluminium nitride, aluminum oxide, zinc oxide, or silicon dioxide. Thermal paste can also contain thermally conductive metal or carbon compounds such as silver, aluminum, liquid gallium, diamond powder, or carbon fibers. The thermal paste can use silicone as a medium to suspend the thermally conductive materials. 
         [0048]      FIG. 4  is a top view of an LED module having a 90° arc and As shown in  FIG. 4 , a LED module  240  includes a circuit board  241  with electrical traces  242 , side-emitting LEDs  243  mounted on the circuit board at one end of the electrical traces  242 , and interboard connector  244  at the other end of the electrical traces  242 . 
         [0049]    The side-emitting LEDs  243  are provided in a region  245  of the LED module  240  bounded by a peripheral  245  of the LED module and two radii  247   a  and  247   b  of the LED module. The side-emitting LEDs  243  can be oriented substantially radially such that the light emitted projects outwards from the center point  247   c  between the two radii  247   a  and  247   b . The side-emitting LEDs  243  can be arranged on a periphery  248  of the LED module  240 . The side-emitting LEDs  243  can be arranged on a curve so as to have an arc  246 . The angle of the arc  246  shown in  FIG. 4  measures 90°. 
         [0050]      FIG. 5  is a top view of an LED module having a 270° arc. As shown in  FIG. 5 , a LED module  340  includes a circuit board  341  with electrical traces  342 , side-emitting LEDs  343  mounted on the circuit board at one end of the electrical traces  342 , and interboard connector  344  at the other end of the electrical traces  342 . 
         [0051]    The side-emitting LEDs  343  are provided in a region  345  of the LED module  340  bounded by a peripheral  345  of the LED module and two radii  347   a  and  347   b  of the LED module. The side-emitting LEDs  343  can be oriented substantially radially such that the light emitted projects outwards from the center point  347   c  between the two radii  347   a  and  347   b . The side-emitting LEDs  343  can be arranged on a periphery  348  of the LED module  340 . The side-emitting LEDs  343  can be arranged on a curve so as to have an arc  346 . The angle of the arc  346  shown in  FIG. 5  measures 270°. 
         [0052]      FIG. 6  is a top view of an LED module having two 90° arcs. As shown in  FIG. 6 , an LED module  440  includes a circuit board  441  with electrical traces  442 , side-emitting LEDs  443  mounted on the circuit board at one end of the electrical traces  442 , and interboard connector  444  at the other end of the electrical traces  442 . 
         [0053]    The side-emitting LEDs  443  exist in two regions  445   a  and  445   b  of the LED module. Region  145   a  is bounded by the periphery  448   a  of the LED module  440  and two radii  447   a  and  447   b  of the LED module  440 . Region  445   b  has an arc  446   b  between the two radii  447   d  and  447   e . The side-emitting LEDs  443  can be oriented substantially radially such that the light emitted projects outwards from the center point  447   c  between the two radii  447   a  and  447   b  and between the two radii  447   d  and  447   e . The side-emitting LEDs  443  can be arranged on a periphery  448   a / 448   b  of the LED module  440 . The side-emitting LEDs  443  can be arranged on a curve so as to have an arc  446   a / 446   b . Each of the two arcs  446   a  and  446   b  shown in  FIG. 6  have and angle measuring 90° and are offset by from each other 90°. 
         [0054]    The configuration of the LED module shown in  FIG. 5  is useful for illuminating two discrete areas using a single LED bulb and electrical connector such as illuminating towards both ends of a hallway using an existing light fixture in the middle of the hallway. While such a configuration has been shown and described, LED light modules with multiple arcs of varying sizes and varying offsets can also be implemented. 
         [0055]      FIG. 7  is a cross-sectional view of an LED bulb according to the first exemplary embodiment of the invention. As shown in  FIG. 7 , an LED bulb  600  has a base  610  with a first surface  620  and a second surface  630 . An electrical connector  625  is located on the first surface  620 . A plurality of LED modules  640  are stacked on the second surface  630 . Each of the LED modules  640  is populated with a plurality of side-emitting LEDs  650 . Heat sinks  660  are used to facilitate heat transfer from LED modules and maintain spacing between the LED modules. Light diffusers  670  cover the LED modules  640  to diffuse the light from the plurality of LEDs  650 . More specifically, each of the light diffusers  670  surrounds a pair of the plurality of LEDs modules  640 . In this embodiment, a pillar  635  is attached to the second surface  630 . The pillar  635  serves as an attachment and stabilization structure for the plurality LED modules  640 . The pillar  635  can also serve as a chimney for heat generated by the LED bulb  600  by removing heat from the heatsinks though the wall of the pillar  635 . The electrical connector  625  can be a screw-in type electrical connector such as an Edison E27 screw-in type connector. The base  610  has openings  615  in the sides of the base  610  between the pillar  635  and the electrical connector  625 . 
         [0056]    The diffuser  670  can be either translucent or transparent. For example, a translucent diffuser can have a diffusion coating on the inside surface and/or outside surface of the cover to diffuse the light emitted from the side-emitting LEDs of the LED modules  640 . In another example, a translucent cover can have a phosphor coating on the inside surface and/or outside surface of the cover to convert ultraviolet light emitted from the side-emitting LEDs of the LED modules  640  into visible light. 
         [0057]    As shown in  FIG. 7 , all of the LED modules  640  in the first exemplary embodiment have the same diameter and the same number of side-emitting LEDs on each of the LED modules  640 . However, embodiments of the invention can contain a plurality of modules in which at least some the LED modules have different diameters and a different number of side-emitting LEDs. For example, an LED bulb may first have six modules that are about three inches wide with twenty-four side-emitting LEDs and modules with successively decreasing numbers of side-emitting LEDs and successively decreasing diameters down to an LED module that is about one inch wide with six side-emitting LEDs. 
         [0058]      FIG. 7  also shows air flow in an exemplary embodiment of the invention. As shown in  FIG. 7 , the openings  615  in the base  610  allow air movement through the base  610  and through the pillar  635  such that the LED modules  640  can be cooled. Although the air flow is shown going through the base  610  and then into the LED module area of the LED bulb  600  shown in  FIG. 7 , the air flow would be reversed if the LED bulb  600  is implemented upside down due to the convection current nature of heated air. 
         [0059]      FIG. 8  shows an isometric view of an LED bulb according to an embodiment of the invention. As shown in  FIG. 8 , an LED bulb  700  has a base  710  with a first surface  720  and a second surface  730 . An electrical connector  725  is located on the first surface  720 . A plurality of LED modules  740  are stacked on the second surface  730 . Each of the LED modules  740  is populated with a plurality of side-emitting LEDs  750 . Heat sinks (not shown) and diffusers (not shown) have been omitted for clarity. In this embodiment, a pillar  735  is attached to the second surface  730 . The pillar  735  serves as an attachment and stabilization structure for the plurality LED modules  740 . The pillar  735  can also serve as a chimney for heat generated by the LED bulb  700  by removing heat from the heatsinks through the wall of the pillar  735 . The electrical connector  725  can be a screw-in type electrical connector, such as an Edison E27 screw-in type connector. The base  710  has openings  715  in the sides of the base  710  between the pillar  735  and the electrical connector  725 . 
         [0060]    When the LED bulb is connected to an electrical appliance via the electrical connector  725 , the position of the LED modules  740  is often dictated by the geometry of the electrical connector  725  and the socket to which it connects. Because the LED bulb in this embodiment is a directional light source, repositioning of the LED modules is desirable. Thus, in an exemplary embodiment of the invention, the pillar  735  can be rotatably connected to the second surface  730  of the base  710 . The pillar  735  can rotate in a plane substantially parallel to the second surface  730  by rotating on an axis  790  that is substantially perpendicular to the second surface  730  as shown in  FIG. 8 . This rotating embodiment facilitates adjustment of the LED modules  740  after the LED bulb  700  has been installed. 
         [0061]      FIG. 9  shows an isometric view of an LED bulb according to an embodiment of the invention. As shown in  FIG. 9 , an LED bulb  800  has a base  810  with a first surface  820  and a second surface  830 . An electrical connector  825  is located on the first surface  820 . A plurality of LED modules  840  are stacked on the second surface  830 . Each of the LED modules  840  is populated with a plurality of side-emitting LEDs  850 . Heat sinks (not shown) and diffusers (not shown) have been omitted for clarity. In this embodiment, a pillar  835  is attached to the second surface  830 . The pillar  835  serves as an attachment and stabilization structure for the plurality LED modules  840 . The pillar  835  can also serve as a chimney for heat generated by the LED bulb  800  by removing heat from the heatsinks through the wall of the pillar  835 . The electrical connector  825  can be a screw-in type electrical connector, such as an Edison E27 screw-in type connector. The base  810  has openings  815  in the sides of the base  810  between the pillar  835  and the electrical connector  825 . 
         [0062]    When the LED bulb is connected to an electrical appliance via the electrical connector  825 , the position of the LED modules  840  is often dictated by the geometry of the electrical connector  825  and the socket to which it connects. Because the LED bulb in this embodiment is a directional light source, repositioning of the LED modules is desirable. Thus, in an exemplary embodiment of the invention, the LED modules  840  can be rotatably connected to the pillar  835 . The LED modules  840  can rotate in a plane substantially parallel to the second surface  830  by rotating on an axis  890  that is substantially perpendicular to the second surface  830  as shown in  FIG. 9 . This rotating embodiment facilitates adjustment of the LED modules  840  after the LED bulb  800  has been installed. 
         [0063]      FIG. 10 . shows an exemplary application of an LED bulb according to an embodiment of the invention. As shown in  FIG. 10 , The environment includes a wall  900 , a wall-mounted light fixture  910  (enlarged to show detail), and objects  920  attached to the wall  900 . The light fixture  910  includes a mounting arm  911 , a shade  912 , and an electrical socket  913 . An LED bulb  100  according to an embodiment of the invention is connected to the electrical socket  913  of the light fixture  910 . Exemplary light rays  930  illustrating light radiating from the LED bulb  900  illuminate the objects  920  attached to the wall  900 . The objects  920  attached to the wall  900  can be pictures, paintings or other decorative furnishings. 
         [0064]    In such an environment, it can be desirable to illuminate only the objects  920  and minimize light emanated into other areas of the environment. An LED bulb according to an embodiment of the invention can be utilized to efficiently achieve the desired lighting effect. No light is wasted by needlessly illuminating other areas of the environment. 
         [0065]      FIG. 11  shows an exemplary application of an LED bulb according to an embodiment of the invention. As shown in  FIG. 11 , the environment includes a ceiling  1050 , a recessed lighting fixture  1010 , and objects  1020  in the environment. The light fixture  1010  includes a housing  1012 , and an electrical socket  1013 . An LED bulb  100  according to an embodiment of the invention is connected to the electrical socket  1013  of the light fixture  1010 . Exemplary light rays  1030  illustrating light radiating from the LED bulb  100  illuminate the objects  1020  in the environment. The objects  1020  can be home or office furnishings including desks, couches, and tables. 
         [0066]    In such an environment, it can be desirable to illuminate only the objects  1020  and minimize light emanated into other areas of the environment. In this application it is unnecessary to have light emanated up and into the lighting fixture as this light would be wasted. An LED bulb according to an embodiment of the invention can be utilized to efficiently achieve the desired lighting effect. No light is wasted by needlessly illuminating the undesired areas. 
         [0067]    The LED bulb  100  in  FIG. 11  connects to the light fixture using an Edison style E27 screw-type electrical connector. The LED bulb  100  is installed by screwing the LED bulb  100 , into the electrical socket  1013  of the recessed lighting fixture  1010 . Generally, Edison-style E27 screw-type electrical connector is not a precision piece of engineering and the socket depth and thread start position will vary between light fixtures. Due to the imprecise nature of the Edison-style E27 screw-type electrical socket and connector, the LED modules of the LED bulb  100  may not be optimally oriented after installation. For example, the LED modules may be facing sideways, or upwards into the light fixture rather than downwards on to the objects  1020 . Accordingly, an embodiment of the invention allows the LED modules to be manually rotated to achieve an optimal orientation. 
         [0068]    Although the preferred embodiments are disclosed having discrete LED layouts and methods of rotation, embodiments of the invention can include multiple LED layouts and other methods of rotation. It will be apparent to those skilled in the art that other various modifications and variations can be made in 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.