Abstract:
According to some embodiments, a light source assembly includes an at least partially transparent or translucent housing; a base plate disposed within the housing, the base plate supporting a plurality of annularly arranged light-emitting units; and a reflector, coupled to the base plate, the reflector having a substantially-annular discontinuous surface, wherein an exterior surface of the reflector is operative to reflect light emitted from the light-emitting units. Numerous other aspects are provided.

Description:
FIELD OF THE INVENTION 
       [0001]    Embodiments of the present invention generally relate to light sources using a reflector that reflects light. 
       BACKGROUND OF THE INVENTION 
       [0002]    Incandescent lamps or light sources commonly provide an illumination pattern in all directions (“omni-directional”). In contrast, light-emitting diodes (LEDs) provide illumination in primarily one direction. Omni-directional LEDs refer to light source products whereby a plurality of LEDs are housed in a bulb or diffuser that may include a reflector, and the LEDs are arranged to provide an illumination pattern in many directions. However, the reflector in conventional omni-directional LEDs may result in a shadow and/or abrupt edge being visible on the housing, which may be undesirable. 
         [0003]    Accordingly, the present inventors have recognized that a need exists for an improved, dependable omni-directional light emitting light source. 
       SUMMARY OF THE INVENTION 
       [0004]    In one embodiment, a light source assembly includes an at least partially transparent or translucent housing; a base plate disposed within the housing, the base plate supporting a plurality of annularly arranged light-emitting units; and a reflector, coupled to the base plate, the reflector having a substantially-annular discontinuous surface, wherein an exterior surface of the reflector is operative to reflect light emitted from the light-emitting units. 
         [0005]    In another embodiment a reflector for use in a light source includes a plurality of annular sections, wherein two adjacent annular sections are connected by one or more connectors, and each section is separated from an adjacent section by a gap, wherein the plurality of sections are operative to reflect light. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Aspects and/or features of the invention and many of their attendant benefits and/or advantages will become more readily apparent and appreciated by reference to the detailed description when taken in conjunction with the accompanying drawings, which drawings may not be drawn to scale. 
           [0007]      FIG. 1  illustrates an omni-directional lamp in a base-up position; 
           [0008]      FIG. 2  is a cross-sectional view of an assembled lamp including a reflector in accordance with some embodiments of the disclosure; and 
           [0009]      FIGS. 3A and 3B  are an enlarged cross-sectional view of a portion of a lamp light reflector having one and two gaps, respectively, according to some embodiments of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Some embodiments may include a light source that includes a reflector having a discontinuous surface. In some embodiments, the reflector may include a plurality of ring-shaped sections with gaps between the sections. Light emitted from light emitting units may be reflected by a reflective ring-shaped surface, and may pass through the gaps between the sections. The combination of reflective surfaces and gaps may reduce the shadow produced by conventional omni-directional light products. 
         [0011]    Another consideration addressed by one or more embodiments is energy efficiency. An international standard for energy efficient consumer products is Energy Star SM . Devices carrying the Energy Star mark, such as light sources, have met certain Energy Star requirements and may use 20-30% less energy than required by federal standards. Regarding Energy Star requirements for light sources, and in particular for ENERGY STAR Lamps V1.1, for an omni distribution luminous intensity (candelas (cd)) may be measured within each vertical plane at a 5° vertical angle increment (maximum) from 0° to 135°. The measurements may be repeated in the vertical planes about the lamp (polar) axis in maximum increments of 22.5°, from 0° to 180°. In particular, to qualify for an Energy Star rating, lamp luminous intensity distribution may emulate that of a reference incandescent lamp as follows: 90% of the luminous intensity measured values (candelas) shall vary by no more than 25% from the average of all measured values in all planes; all measured values (candelas) shall vary by no more than 50% from the average of all measured values. Additionally, the light distribution zone may be vertically axially asymmetrical, where at least 5% of the flux (lumens) may be emitted in the 135° to 180° zone, as illustrated by the omni-directional light source  100  in  FIG. 1 . 
         [0012]    To meet Energy Star requirements, conventional omni-directional LEDs typically include a particular ratio of LEDs positioned central to a reflector and around an exterior of the reflector. While some conventional omni-directional LEDs have not included centrally positioned LEDs, to reduce LED counts and thereby reduce costs, for example, the shadow in these light sources may increase and optical efficiency may decrease compared to conventional omni-directional LEDs including interior and exterior LEDs. 
         [0013]      FIG. 2  is a cross-sectional view of an assembled lamp or light source  200  including a housing  202 , a reflector  204 , a plurality of light emitting units  206  and a base plate  208  according to some embodiments. In one or more embodiments, the light source  200  may qualify for an Energy Star rating. 
         [0014]    The housing  202  may be coupled to a lamp base  212 . The housing  202  may have an A-line shape, such as that depicted in  FIG. 2 , or may be any other suitable shape for directing and diffusing light from light emitting units  206 . In some embodiments, the housing  202  may be transparent to all light. In some embodiments, the housing  202  may include particles that scatter light with a translucent appearance. An open end  214  of the housing may be selectively coupled to the lamp base  212 . While the lamp base  212  shown in  FIG. 2  includes a recess  216  to receive a portion of the housing  202 , any other suitable coupling methods may be used. 
         [0015]    The lamp base  212  may include the base plate  208 . While the base plate  208  shown herein is substantially circular-shaped, any other suitable shape may be used. When assembled, the base plate  208  is positioned within the housing  202  of the light source  200 . The base plate  208  may be one of coupled to the lamp base  212  (e.g., via a mounting hole (not shown) engageable with a screw or fastener, for example) and integrally formed with the lamp base  212 . The base plate  208  may include a central hole  211  that may provide a path for wires to connect a driver to the light emitting units  206 , or may provide a space for push-in connectors that may mount to a circuit board. The base plate  208  may include a top surface  218  and bottom surface  220  that are planar and parallel to each other. In one or more embodiments, the plurality of light emitting units  206  may be mounted to the top surface  218  of the base plate  208 . The base plate  208  may be a circuit board connected electrically to the light emitting units  206  to provide power to the light emitting units  206 . The light emitting units  206  may be light-emitting diodes (LEDs) or any other suitable light source. In one or more embodiments, the light emitting units  206  may be annularly arranged around the base plate  208 . In one or more embodiments, the base plate  208  may include a base plate opening  224  that may correspond with a lamp base opening  226 . While the base plate opening  224  and lamp base opening  226  are annularly shaped, as shown in  FIG. 2 , the openings  224 ,  226  may be any suitable shape. 
         [0016]    The reflector  204  may include a reflector base  228 . As shown in  FIG. 2 , the reflector  204  may be selectively coupled to the light source  200  whereby the reflector base  228  may be first received by the base plate opening  224  and then by the lamp base opening  226 . In one or more embodiments, the reflector base  228  may be secured in the openings  224 ,  226  via any suitable securing means (e.g., adhesive, pressure-fit, etc.). In one or more embodiments, the reflector base  228  may include a mounting hole  230 . The mounting hole  230  may extend through the reflector base  228 . The mounting hole  230  may be configured to provide clearance for a screw or fastener to secure the reflector  204  to the base plate  208 . In one or more embodiments, the mounting hole  230  may be configured to engage with a screw or fastener to secure the reflector  204  to the base plate  208 . In some embodiments, the reflector  204  may include a groove  231  proximate the mounting hole  230  to allow clearance for a tool to secure the reflector  204  to the base plate  208 . In one or more embodiments, the base plate  208  may include a recess instead of the opening  224  to receive the reflector base  228 . In one or more embodiments, the reflector  204  may be integrally formed with the base plate  208  or may be secured to the base plate  208  via any suitable securing means (e.g., fastening means, screws, adhesives, etc.). 
         [0017]    The reflector  204  may include an interior surface  232  and an exterior surface  234 . The interior  232  and exterior  234  surfaces may be reflective and may be made from the same or different materials. In one or more embodiments, the reflector  204  may be made from a reflective material or may be coated with a reflective material. In one or more embodiments, the reflector  204  may be mounted to the base plate  208  such that the light emitting units  206  are arranged circumferentially between an exterior surface  234  of the reflector  204  and an edge  235  of the base plate  208 . In one or more embodiments, an arrangement of light emitting units  206  on the base plate  208  within the interior surface  232  of the reflector  204  may be avoided to provide for more efficient thermal usage and reduced heatsink designs, while the reflector  204  provides a reduced shadow compared to conventional omni-directional light sources, as further described below. While the reflector  204  shown herein may be substantially funnel- or annularly-shaped, having a cross-section that gradually decreases in a direction towards the reflector base  228 , any suitable shaped reflector may be used. 
         [0018]    In one or more embodiments, the reflector  204  may be discontinuous and include a bottom section  236  and one or more upper sections  238 , whereby each adjacent section  236 ,  238  is separated by at least one gap  240 . As described further below, the discontinuous aspect of the reflector  204  (e.g., split into two or more sections) may allow precisely targeted or directed light to pass through the gap(s) in the reflector  204 . Of note, the precisely targeted light may reduce and/or eliminate the abrupt shadow edge provided with conventional omni-directional LEDs. Additionally, by precisely targeting the light, Energy Star requirements may be met for a variety of light emitting unit distributions, including a distribution with no centrally located light emitting unit. In one or more embodiments, a gap width may be 5% to 20% of the overall height of the reflector  204 , but other suitable gap widths may be used. In one or more embodiments, the gap width may be approximately 12% of the overall height of the reflector  204 . In one or more embodiments, the gap width may be based on the placement of the light emitting units  206  relative to the exterior surface  234  of the reflector  204 . For example, as the distance between the light emitting units  206  and the exterior surface  234  of the reflector  204  increases, the size of the gap may increase such that a suitable amount of light may be precisely targeted to meet Energy Star requirements, for example. In one or more embodiments, the reflector  204  may be formed as a single article and the sections  236 ,  238  may be formed by removing at least a portion of the reflector  204 , such that the sections  236  may be connected to each other via one or more connectors  239 , (e.g., the remaining portion of the reflector) integrally formed with the reflector  204 . In other embodiments, the sections  236  and  238  may be separately formed and coupled together by one or more connectors  239 . The bottom section  236  may be integrally formed with the reflector base  228 . In one or more embodiments, the exterior surface of the bottom section  236  may be perpendicular to the top surface  218  of the base plate  208 . In one or more embodiments, the exterior surface of the bottom section  236  may be curved. In one or more embodiments, the exterior surface  234  of the upper section  238  may be curved or arc-shaped. In one or more embodiments, the curve of the upper section  238  may extend outward from a bottom edge  242  of the upper section  238  towards a top edge  244  of the upper section  238  such that a circumference of the top edge  244  is greater than a circumference of the bottom edge  242 . In one or more embodiments, the curve of the upper section  238  may be such that the top edge  244  of the upper section  238  is vertically aligned with at least one of the base plate edge  235  and an outer edge  246  of the light emitting unit  206  positioned closest to the base plate edge  235 , such that at least a portion of the upper section  238  is located over the light emitting unit  206 . In one or more embodiments, a point on an outer edge  246  of a light emitting unit  206  is positioned in a plane which is substantially perpendicular to the base plate  208 , and wherein at least one section of the reflector  204  intersects that plane. 
         [0019]    In operation, as the plurality of light emitting units  206  emit light in substantially the same direction, the reflector  204  guides the light emitted by the light emitting units  206 , as indicated by the light traveling paths in  FIGS. 3A and 3B . Specifically, in both  FIGS. 3A and 3B , light ray L 2  and L 3  emitted from one of the light emitting units  206  are reflected by the reflective surface of the bottom/lower section  236  of the reflector  204  and upper section  238  of the reflector  204 , respectively, towards a region of the housing  202  which is closer to the base plate than to the zenith of the housing. In addition to a light ray L 1  emitted from the light emitting unit  206  passing through the gap  240 , the reflector  204  reflects the incident light rays L 2  and L 3  to expand the illumination angle. The gaps  240  may provide for the uplight (e.g., light emitted between 18 degrees and 38.5 degrees) to be targeted, as opposed to a fixed central LED output, for example. In one or more embodiments, multiple gaps  240  ( FIG. 3B ), may provide for additional opportunities to direct the uplight (e.g., L 1  and L 4 ), and generally provide better light control. One of the benefits of targeting the uplight is that the light rays may be directed to reduce the appearance of a shadow edge that may otherwise be apparent in gap-less reflectors. As described above, the interior surface  232  of the reflector may be reflective and reflect light incident thereon, in one or more embodiments. For example, in one or more embodiments, a portion of the light that contacts the housing  202  may be reflected and may then contact the interior surface  232  of the reflector  204  and be further reflected. As another example, a portion of the light may directly contact the interior surface  232  of the reflector as it passes through the gap. A benefit of the reflective interior surface  232  of the reflector is that a reflective interior surface  232  may reduce light loss. 
         [0020]    The above descriptions and/or the accompanying drawings are not meant to imply a fixed order or sequence of steps for any process referred to herein; rather any process may be performed in any order that is practicable, including but not limited to simultaneous performance of steps indicated as sequential. 
         [0021]    Although the present invention has been described in connection with specific exemplary embodiments, it should be understood that various changes, substitutions, and alterations apparent to those skilled in the art can be made to the disclosed embodiments without departing from the spirit and scope of the invention as set forth in the appended claims.