Patent Publication Number: US-8967837-B2

Title: Solid state light with features for controlling light distribution and air cooling channels

Description:
BACKGROUND 
     The energy efficiency of lighting has become an important consideration in industrial, consumer, and architectural lighting applications. With the advances in solid state light technology, light emitting diodes (LEDs) have become more energy efficient than fluorescent lights. Further, the marketplace has a large established fixture base for Edison, fluorescent and high intensity discharge lights. These types of applications present a significant technical challenge for LEDs due to their inherent point source nature, and the need to operate the LEDs at relatively low temperatures. Today there are many solutions addressing these issues, including fans, thermal sinks, heat pipes and the like. However, these approaches limit the applications by adding complexity, cost, efficiency loss, added failure modes, an undesirable form factor, and light distribution. The need remains to find a solution that can provide optical and electrical efficiency benefits, at attractive manufacturing costs and design. 
     SUMMARY 
     A first solid state light, consistent with the present invention, includes a shell having an interior volume and surface texture, a light section coupled to the shell, and a light source board coupled to the light section. At least one solid state light source is on the light source board and transmits light into the interior volume. At least a portion of the light exits from the shell and is redirected by the texture. 
     A second solid state light, consistent with the present invention, includes a shell having an interior volume and surface texture, a light section coupled to the shell, and a light source board coupled to the light section. At least one solid state light source is on the light source board at an edge of the shell. The light source transmits light into the edge and into the interior volume. At least a portion of the light exits from the shell and is redirected by the texture. 
     A third solid state light, consistent with the present invention, includes a shell having an interior volume, a light section coupled to the shell, and a light source board coupled to the light section. A first solid state light source is on the light source board at an edge of the shell, and a second solid state light source is on the light source board within or adjacent the interior volume. The first light source transmits light into the edge, the second light source transmits light into the interior volume, and at least a portion of the light from the first and second light sources exits from the shell. 
     A fourth solid state light, consistent with the present invention, includes a shell having an interior volume and surface texture, a light section coupled to the shell, a light source board coupled to the light section, and a pedestal heat sink on the light source board. At least one solid state light source is on the pedestal heat sink and transmits light into the interior volume. At least a portion of the light exits from the shell and is redirected by the texture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, explain the advantages and principles of the invention. In the drawings, 
         FIG. 1  is an exploded perspective view of a first embodiment of a solid state light having a light source board with vents; 
         FIG. 2  is a side sectional view of the first embodiment; 
         FIG. 3  is an exploded perspective view of a second embodiment of a solid state light having a light source board without vents; 
         FIG. 4  is a side sectional view of the second embodiment; 
         FIG. 5  is an exploded perspective view of a third embodiment of a solid state light having an alternative light source board; 
         FIG. 6  is a side sectional view of the third embodiment; 
         FIG. 7  is an exploded perspective view of a fourth embodiment of a solid state light using light transport through the shell edge and interior volume to distribute light; 
         FIG. 8  is a side sectional view of the fourth embodiment; 
         FIG. 9  is an exploded perspective view of a fifth embodiment of a solid state light having a pedestal heat sink for light sources; 
         FIG. 10  is a side sectional view of the fifth embodiment; 
         FIG. 11  is a perspective view of a pedestal heat sink having a conical shape; 
         FIG. 12  is a perspective view of a pedestal heat sink having an inverted conical shape; 
         FIG. 13  is a perspective view of a pedestal heat sink having two conical shapes; 
         FIG. 14  is a perspective view of another pedestal heat sink having two conical shapes; 
         FIG. 15  is a side sectional view of a solid state light shell having texture on an inner surface; 
         FIG. 16  is a side sectional view of a solid state light shell having texture on an outer surface; 
         FIG. 17  is a side sectional view of a solid state light shell having texture on inner and outer surfaces; 
         FIG. 18  is a side sectional view of a solid state light shell having a transflective film on an inner surface; 
         FIG. 19  is a diagram illustrating redirection of light by texture on a light shell; and 
         FIG. 20  is another diagram illustrating redirection of light by texture on a light shell. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention include an LED light bulb having advanced bulb shells, small-size heat sinks, and various configurations of LEDs or other solid state light sources. The advanced bulb shells can contain surface texture or optical transflective films to control the light distribution from the bulb. The light bulb is equipped with cooling air channels that aid in the dissipation of the heat. The LED light sources can be configured in various ways, and the lights can include various features, to optimize the performance and light distribution curve of the light bulb. 
     Examples of solid state lights are described in the following, all of which are incorporated herein by reference as if fully set forth: U.S. Pat. No. 8,487,518; and U.S. Patent Applications Publication Nos. 2012/0194054 and 2011/0032708. 
       FIGS. 1 and 2  are exploded perspective and side sectional views, respectively, of a first embodiment of a solid state light  10  having a light source board with vents. Light  10  includes a shell having an upper portion  12  and a lower portion  14 . Upper portion  12  has one or more apertures (vents)  13 . The shell has a first surface  11  and a second surface  15  opposite first surface  11  and an edge between the surfaces. Second surface  15  forms an interior volume of the shell. 
     A light section  16  includes a ridge  17 , a ridge  18 , and one or more apertures (vents)  19 . Ridge  17  provides support for the shell at the edge formed by first and second surfaces  11  and  15  when upper and lower portions  12  and  14  are mated together. Ridge  18  provides support for a light source board  22 . Light section  16  also includes a base portion  20 . A base  21  is attached to base portion  20  and provides for connection to a power source. 
     Light source board  22  includes solid state light sources  25  and a driver  24  for controlling the light sources. Light source board  22  also includes one or more apertures (vents)  26 , which provide for air flow between light section  16  and the interior volume of the shell when light source board  22  is mounted on ridge  18 . Apertures  26  also provide for air flow between apertures  13  and  19  such that air flow is provided through the light for cooling the light. Air flow is also provided through the light by apertures  13  providing for air flow into and out of the interior volume of the shell and apertures  19  providing for air flow into and out of light section  16 . Light sources  25  transmit light into the interior volume of the shell and through the shell such that at least a portion of the light is distributed from the first surface to provide for illumination from the light. 
     Light  10  can optionally include a light mixing chamber  27  over light sources  25 . For example, light mixing chamber  27  can be implemented with a transparent or translucent dome-shaped covering over light sources  25  to provide light mixing before the light from light sources  25  is transmitted through the interior volume to the shell. Light mixing chamber  27  can include texture on its inner surface, outer surface, or both inner and outer surfaces. Examples of texture are provided below. 
       FIGS. 3 and 4  are exploded perspective and side sectional views, respectively, of a second embodiment of a solid state light  30  having a light source board without vents. Light  30  includes a shell having an upper portion  32  and a lower portion  34 . Upper portion  32  has one or more apertures (vents)  33 . The shell has a first surface  31  and a second surface  35  opposite first surface  31  and an edge between the surfaces. Second surface  35  forms an interior volume of the shell. 
     A light section  36  includes a ridge  37 , a ridge  38 , and one or more apertures (vents)  39 . Ridge  37  provides support for the shell at the edge formed by first and second surfaces  31  and  35  when upper and lower portions  32  and  34  are mated together. Ridge  38  provides support for a light source board  42 . Light section  36  also includes a base portion  40 . A base  41  is attached to base portion  40  and provides for connection to a power source. 
     Light source board  42  includes solid state light sources  45  and a driver  44  for controlling the light sources. Light source board  42  does not include apertures and thus does not allow air flow between light section  36  and the interior volume of the shell when light source board  42  is mounted on ridge  38 . Air flow is provided through the light for cooling the light by apertures  33  providing for air flow into and out of the interior volume of the shell and apertures  39  providing for air flow into and out of light section  36 . Light sources  45  transmit light into the interior volume of the shell and through the shell such that at least a portion of the light is distributed from the first surface to provide for illumination from the light. 
       FIGS. 5 and 6  are exploded perspective and side sectional views, respectively, of a third embodiment of a solid state light  50  having an alternative light source board. Light  50  includes a shell having an upper portion  52  and a lower portion  54 . Upper portion  52  has one or more apertures (vents)  53 . The shell has a first surface  51  and a second surface  55  opposite first surface  51  and an edge between the surfaces. Second surface  55  forms an interior volume of the shell. 
     A light section  56  includes a ridge  57 , a ridge  58 , and one or more apertures (vents)  59 . Ridge  57  provides support for the shell at the edge formed by first and second surfaces  51  and  55  when upper and lower portions  52  and  54  are mated together. Ridge  58  provides support for a light source board  62 . Light section  56  also includes a base portion  60 . A base  61  is attached to base portion  60  and provides for connection to a power source. 
     Light source board  62  includes solid state light sources  65  and a driver  64  for controlling the light sources. Light source board  62  also includes a center opening, which provides for air flow between light section  56  and the interior volume of the shell when light source board  62  is mounted on ridge  58 . The opening in light source board  62  also provides for air flow between apertures  53  and  59  such that air flow is provided through the light for cooling the light. Air flow is also provided through the light by apertures  53  providing for air flow into and out of the interior volume of the shell and apertures  59  providing for air flow into and out of light section  56 . Light source board  62  can have a ring shape, as shown, or other shapes depending upon the shape of light section  56 . 
     Light sources  65  are located at least partially at the edge of the shell formed by first and second surfaces  51  and  55 . An optional gap can exist between light sources  65  and the edge. Some light from light sources  65  is transmitted and optically coupled into the shell at the edge, and transmitted through the shell, for example by total internal reflection, until the light exits from first surface  51  or second surface  55 . Some light from light sources  65  is transmitted into the interior volume of the shell. At least a portion of the light transmitted into the edge and the interior volume is distributed from the first surface to provide for illumination from the light. 
       FIGS. 7 and 8  are exploded perspective and side sectional views, respectively, of a fourth embodiment of a solid state light  70  using light transport through the shell edge and interior volume to distribute light. Light  70  includes a shell having an upper portion  72  and a lower portion  74 . Upper portion  72  has one or more apertures (vents)  73 . The shell has a first surface  71  and a second surface  75  opposite first surface  71  and an edge between the surfaces. Second surface  75  forms an interior volume of the shell. 
     A light section  76  includes a ridge  77 , a ridge  78 , and one or more apertures (vents)  79 . Ridge  77  provides support for the shell at the edge formed by first and second surfaces  71  and  75  when upper and lower portions  72  and  74  are mated together. Ridge  78  provides support for a light source board  82 . Light section  76  also includes a base portion  80 . A base  81  is attached to base portion  80  and provides for connection to a power source. 
     Light source board  82  includes solid state light sources  86  and  87 , and a driver  84  for controlling the light sources. Light source board  82  also includes one or more apertures (vents)  85 , which provide for air flow between light section  76  and the interior volume of the shell when light source board  82  is mounted on ridge  78 . Apertures  85  also provide for air flow between apertures  73  and  79  such that air flow is provided through the light for cooling the light. Air flow is also provided through the light by apertures  73  providing for air flow into and out of the interior volume of the shell and apertures  79  providing for air flow into and out of light section  76 . 
     Light sources  86  are located at the edge of the shell optionally with a gap between the light sources and the edge. Light sources  86  transmit light into the shell at the edge. The light from light sources  86  is optically coupled into the shell at the edge and transported within the shell, for example by total internal reflection, until the light exits from first surface  71  or second surface  75 . Light sources  87  are located adjacent or within the interior volume of the shell. Light from light sources  87  is transmitted into the interior volume and through the shell. An optional reflective material  88 , for example a metal ring or reflective film, can be located between light sources  86  and  87 . An example of a reflective film is the Enhanced Specular Reflective (ESR) film product from 3M Company, St. Paul, Minn. At least a portion of the light transmitted into the edge and the interior volume is distributed from the first surface to provide for illumination from the light. 
       FIGS. 9 and 10  are exploded perspective and side sectional views, respectively, of a fifth embodiment of a solid state light  90  having a pedestal heat sink for light sources. Light  90  includes a shell having an upper portion  92  and a lower portion  94 . Upper portion  92  has one or more apertures (vents)  93 . The shell has a first surface  91  and a second surface  95  opposite first surface  91  and an edge between the surfaces. Second surface  95  forms an interior volume of the shell. 
     A light section  96  includes a ridge  97 , a ridge  98 , and one or more apertures (vents)  99 . Ridge  97  provides support for the shell at the edge formed by first and second surfaces  91  and  95  when upper and lower portions  92  and  94  are mated together. Ridge  98  provides support for a light source board  102 . Light section  96  also includes a base portion  100 . A base  101  is attached to base portion  100  and provides for connection to a power source. 
     Light source board  102  includes solid state light sources  107  on a pedestal heat sink  106  and a driver  104  for controlling the light sources. Light source board  102  also includes one or more apertures (vents)  105 , which provide for air flow between light section  96  and the interior volume of the shell when light source board  102  is mounted on ridge  98 . Apertures  105  also provide for air flow between apertures  93  and  99  such that air flow is provided through the light for cooling the light. Air flow is also provided through the light by apertures  93  providing for air flow into and out of the interior volume of the shell and apertures  99  providing for air flow into and out of light section  96 . Light sources  107  transmit light from the interior volume of the shell through the shell such that at least a portion of the light is distributed from the first surface to provide for illumination from the light. 
     Pedestal heat sink  106  is in sufficient contact, directly or indirectly, with solid state light sources  107  in order to conduct and dissipate heat from the solid state light sources. Heat sink  106  can be directly in physical contact with solid state light sources  107  or indirectly in contact with them such as through other components. Heat sink  106  can be implemented with a metal material such as aluminum. The heat sink can also be implemented with other metal materials, ceramic materials, or combinations of metals and ceramics. The heat sink can be hollow, as shown, in order to provide a space for driver circuit  104  and a cap over the driver circuit. Alternatively, if the driver circuit is located elsewhere, the heat sink can be composed of a solid material. 
       FIGS. 11-14  are perspective views illustrating examples of various shapes of pedestal heat sink  106  for the fifth embodiment shown in  FIGS. 9 and 10 . The pedestal heat sink can be shaped in order to direct light from the solid state light sources in a particular direction to the shell within the interior volume. For example, the pedestal heat sink can be shaped to direct light from the light sources to the shell for substantially uniform distribution of light from outer surface of the shell.  FIG. 11  illustrates a pedestal heat sink  110  having a truncated cone shape with solid state light sources  111  on the sides and top of the heat sink.  FIG. 12  illustrates a pedestal heat sink  112  having an inverted truncated cone shape with solid state light sources  113  on the sides and top of the heat sink.  FIG. 13  illustrates a pedestal heat sink  114  having two truncated cone shapes with solid state light sources  115  on the sides and top of the heat sink.  FIG. 14  illustrates a pedestal heat sink  116  also having two truncated cone shapes with solid state light sources  117  on the sides and top of the heat sink. The pedestal heat sink can also be shaped to direct light from the light sources in particular directions by being on a contoured board such as flexible board. 
       FIGS. 15-17  are side sectional views illustrating surface texture on a solid state light shell.  FIG. 15  illustrates texture  121  on the inner surface of a shell  120 .  FIG. 16  illustrates texture  123  on the outer surface of a shell  122 . A layer  127  such as a transparent thin film can optionally be included over texture  123  with an air gap between layer  127  and texture  123 , or layer  127  can be implemented with a low index material applied over texture  123 . Layer  127  can be used over texture  123  to provide the shell with, for example, an outer surface having a smooth appearance and feel.  FIG. 17  illustrates texture  125  and  126  on the inner and outer surfaces, respectively, of a shell  124 . The shell can thus have texture on the first (outer) surface only, the second (inner) surface only, or on both the outer and inner surfaces. Also, the shell can have texture on the entire outer and inner surfaces or have texture on only portions of the outer and inner surfaces. 
     The texture on the shell preferably protrudes from a surface of the shell and is located on the first (outer) surface of the shell. Alternatively, the texture can be indented into the shell. The texture can be, for example, molded into the shell during formation of it or applied to the shell after it is formed. The texture can include, for example, pyramids, ribs, prisms, cones, half-circles, or other shapes. The pyramids can have, for example, a 90° (or 105° or 60° or other angles) pyramid pattern. The texture redirects light at an angle, and the individual texture features can thus be tailored for overall light redirection from the shell. In particular, the shape, density, and placement of the texture features can be varied to achieve a various light distribution curves or appearances of the light when the light sources are on. For example, the texture can be tailored such that the light distribution curve of the solid state light achieves light distribution properties resembling those properties of an incandescent light bulb. The texture can optionally reflect some light in addition to redirecting and transmitting light. 
       FIG. 18  is a side sectional view of a portion of a solid state light shell  128  having a transflective film  129  on an inner surface. The transflective film can cover the entire inner surface of the shell or only a portion of the inner surface. As with texture, the transflective film can be used to achieve various light distribution curves of the light. The reflectance of the film can be varied based upon the shape of the shell. The transflective film can be on the surface of the shell by being directly on it (in physical contact), separated by an air gap, or separated by other components such as an adhesive or another film. An example of a transflective film is the 3M VIKUITI DBEF-Q Film product from 3M Company, St. Paul, Minn. The shell can alternatively include both surface texture and transflective film. 
       FIGS. 19 and 20  are diagrams illustrating redirection of light by surface texture on a solid state light shell.  FIG. 19  illustrates a texture feature  130  providing for redirection of light as represented by line  131 .  FIG. 20  illustrates another texture feature  132  providing for redirection of light as represented by line  133 . The x- and y-axes in  FIGS. 19 and 20  indicate the size of the features in arbitrary units. Texture features  130  and  132  can be implemented with, for example, prisms or pyramids protruding from the outer surface of the shell. By varying the shape of the texture features, for example the angles within prisms or pyramids, and the location of the texture features on the shell, the texture features can be tailored to redirect light in various ways across the shell. 
     The following are exemplary materials, components, and configurations for the solid state lights described herein. 
     The light sources can be implemented with LEDs, organic LEDs (OLEDS), or other solid state light sources. The lights can include one light source or multiple light sources. The light sources can be located in different zones on the light source board, for example in a central area and a perimeter as shown in  FIGS. 7 and 8 , in order to optimize the performance and light distribution curve of the light or achieve a particular appearance of the light when the light sources are on. 
     The light section can be implemented with, for example, a metal material such as aluminum and with an insulator for the base portion inside the base. The light section can also be implemented with other metal materials or ceramic materials. The light section can function as a heat sink, and a size of the light section can be adjusted to dissipate a particular amount of heat from the light. The light section can have a round or circular shape, as shown, or other shapes depending upon the shape of the shell, for example. 
     The base can be implemented with, for example, an Edison base for use with conventional light bulb sockets or a base configured for connection to other types of light fixture connections. 
     The light source boards, including alternative light source boards, can be implemented with a material providing sufficient mechanical support for the light sources and optionally conducting heat from the light sources for use in dissipating the heat. Examples of light source boards include the SMJE-2V12W2P4 (Acrich2) product from Seoul Semiconductor Co., Ltd. The light source boards would have electrical connections with the base and the light sources in order to receive power from the base when connected to a power source and drive the light sources. The light source board in some embodiments has at least one aperture when coupled to the light section, which may be accomplished by the light source board forming an aperture with the light section or having a complete aperture. The light source boards can be coupled to the light section by, for example, being supported by a ridge or other component, or being adhered to a ridge or other component with an adhesive, fasteners, or in other ways. 
     The driver can be implemented with one or more integrated circuit chips, or other circuit components, having an LED driver or other solid state light source driver. The drivers can be located on the light source board, as shown, or elsewhere on a separate board. Examples of such LED drivers include the driver circuits available from Seoul Semiconductor Co., Ltd.; JMK Optoelectronic Co., Ltd.; and InterLight Optotech Corporation. 
     The shells can be implemented with, for example, a transparent or translucent material capable of receiving light from the one or more solid state light sources and emitting the light. For example, the shells can be made of an optically suitable material such as acrylic, polycarbonate, polyacrylates such as polymethyl methacrylate, polystyrene, glass, or any number of different plastic materials having sufficiently high refractive indexes. The material can be cast or molded, for example, to form the shells. The surfaces of the shells can optionally be polished. The shells can optionally include bulk scatter elements, such as particles within the shells, to provide for a soft glow appearance when the shells are illuminated by the solid state light sources. Based upon a placement of the light sources, the shells can function as a light guide to transmit light within them, for example by total internal reflection, and can transmit light through the shells, for example from the interior volume through the inner surface and exiting from the outer surface. 
     The shells can have a single aperture or multiple apertures. Although the lights described above only have apertures in the upper portion, the shells can also or alternatively have apertures in the lower portion. The apertures can have various shapes. For example, the apertures can be in the shape of narrow slits as shown in the lights described above or can be in other shapes such as circles, triangles, or squares. 
     The top and bottom portions of the shells can be adhered together with an adhesive, for example, or they can otherwise be removably attached together. The shells can have a bulb shape, as shown, or other shapes such as a cylinder or cone. The shells can be composed of multiple sections joined together, for example the upper and lower portions shown, or a single unitary piece of material. The shells can be coupled to the light section by, for example, being supported by a ridge or other component, or being adhered to a ridge or other component with an adhesive, fasteners, or in other ways.