Abstract:
A method and apparatus for directing light from a light source along a trajectory to avoid particular obstacles and provide uniform illumination of a surface having a particular geometry such as a cylindrical geometry is described. The surface may enclose components such as PCBs that provide particular functionality that operate as obstacles to a light beam.

Description:
BACKGROUND 
       [0001]    Illumination systems are critical for many devices including computer displays, televisions and for entertainment purposes. Devices may utilize lighting for practical purposes to provide communication of various events or for aesthetic or decorative purposes. As many devices utilize complex geometries and may incorporate many functional components serving as obstacles such as electronics in printed circuit boards (“PCBs”), directing light to traverse a particular path while avoiding these obstacles becomes a challenging problem. The directing of light along a particular path in such a device may be complicated by practical design requirements, which may require for example a power source such as a battery pack to be placed inside the device or a switch to be positioned in a particular position. All of these functional components may generate obstacles for the desired transmission of light along a particular trajectory. 
         [0002]    It is often desirable to provide uniform lighting of a device or object having a particular geometry such as a cylinder. In industrial design, an object may have a particular function that may require other components that may complicate the uniform lighting of an enclosing geometry such as a cylinder. For example, a device may require electronic components for particular functionality. The electronic components may be enclosed in a case having a particular geometry such as a cylindrical geometry. The electronic components or other hardware required for the functioning of the device may create particular challenges for uniform illumination of the enclosing case due to scattering of the light off of the components. 
         [0003]    The use of an optical waveguide for the directing of light along a particular trajectory is well known. Optical waveguides may operate by capitalizing on a phenomenon known as total internal reflection wherein the index of refraction of the material forming the waveguide in relationship to the index refraction of a surrounding medium such as air is arranged to achieve a particular critical angle. Light rays arriving at the critical angle or greater at the surface between the two materials are refracted along the boundary. 
         [0004]    Methods for uniform illumination of planar flat panel displays such as transreflective liquid crystal displays (“LCDs”) are also known. For example, light emitting diodes (“LEDs”) may be used to produce uniform illumination for liquid crystal displays by converting an LED&#39;s output flux distribution to a uniform one with plastic, injection-molded light pipes. In particular, an aspheric light pipe may be used as a wavequide. 
         [0005]    The use of smooth sides in a wave guide parallel to the direction of propagation of light but utilizing a diffused exit end with random critical angles to allow a high probability that light rays can escape is also known. In addition, light guides may be bent to go around corners. Wedge light guides having either a planar surface or a curved surface may also be used, the former of which may be utilized to backlight transreflective LCD displays is also known. 
         [0006]    However, apparatus for bending light around an obstacle are not well known. And, in particular, the bending of light around an obstacle such as a PCB for illumination of a particular surface geometry such as a cylinder is not known. Thus, there is a need for a method and apparatus for directing light around an obstacle such as electronic components, so that the light may provide maximum illumination of a particular surface geometry such as a cylindrical geometry. 
       SUMMARY 
       [0007]    A method and apparatus for directing light from a light source along a trajectory to avoid particular obstacles and provide uniform illumination of a surface having a particular geometry such as a cylindrical geometry is described. The surface may enclose components such as PCBs that provide particular functionality that operate as obstacles to a light beam. 
         [0008]    According to one embodiment, a first clear cylindrical surface may be enclosed by a second opaque cylindrical surface. At least one portion of the opaque cylindrical surface may be removed to create respective windows allowing the escaping of light. 
         [0009]    According to another embodiment, an optical waveguide may be arranged in an aspherical configuration and directly coupled to a light source such as an LED light source. The optical wave guide may comprise an inner portion comprised of a material having a first index of refraction and a textured outer portion having a second index of refraction. The optical wave guide may comprise polycarbonate material and may be further configured in an aspherical form. 
         [0010]    This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The illustrative embodiments will be better understood after reading the following detailed description with reference to the appended drawings, in which: 
           [0012]      FIG. 1   a  is a block diagram of a lighted device. 
           [0013]      FIGS. 1   b  and  1   c  depict a schematic representations of an exemplary devices. 
           [0014]      FIG. 2  depicts an interior portion of an exemplary device that includes an optical waveguide for directing light around internal components and to provide uniform illumination of a cylindrical surface housing the device. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The inventive subject matter is described with specificity to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, it is contemplated that the claimed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. 
         [0016]      FIG. 1   a  is a block diagram of an exemplary lighted device. As will become evident below, an exemplary lighted device having the structural aspects depicted in  FIG. 1   a  may comprise a particular geometry that may require the transmission of light around various obstacles or obstructions in order to illuminate a surface or other are of the device. 
         [0017]    Device  102  may processor  150 , power supply  158 , RF transmitter/receiver  152 , antenna  154  and light source  156 . Power supply  158  may provide power for processor  150 , RF transmitter/receiver  152 , light source  156  and any other electronic components that may be installed on device not shown in  FIG. 1   a.  Device  102  may transmit information regarding game play with video game console  160  via RF transmitter/receiver  152  and antenna  154 . Light source  156  may provide aesthetic as well as communicative lighting of device  102 . Light source  156  may be a light emitting diode (“LED”) or other light source. In other words, light source  156  may provide lighting of device  102  in order to enhance game play as well as to communicate various messages or information regarding game play for titles running on video game console  160 . For example, as discussed herein according to one embodiment device  102  is configured as a wand in a cylindrical shape and it is desired that light source  156  be configured to transmit light to illuminate a cylindrical surface of device  102 . 
         [0018]    Processor  150  may perform various functions on device  102  for control of the device and may also control the exchange of information with video game console  160 . Device  102  may also include a printed circuit board (“PCB”), which may include circuitry for performing various functions such as control of light source  156  based on commands from processor  150 . The PCB may also provide other functionality relating to powering the device In particular, received RF signals from an video game console  160  may be received by device  102 , the signals processed by the processor  150  on device  102  and the processor may then control the light source of device  102  as a function of the received signals. 
         [0019]    As device  102  may require many electronic or structural components such as a PCB, a battery compartment for housing batteries needed to power device  102 , light generated by light source  156  may be blocked or otherwise impeded impeding the usefulness and drama provided by the light source  156 . Typically the geometry of various functional and structural components such as a PCB or power supply  156  is not easily controllable and thus there may exist significant potential for these components to serve as obstacles for transmission of light via light source  156 . 
         [0020]      FIG. 1   b  depicts a schematic representation of an exemplary device. Device  102  may include cylindrical surface  105 , which may include one or more windows  110 . Each window  110  may allow emission of light either for aesthetic purposes to alert a user of device  102  regarding some event or situation (e.g., relating to game play). Cylindrical surface  105  may comprise a tapered cylindrical sleeve or a uniform cylindrical sleeve. According to one embodiment, it is desirable to provide uniform illumination of cylindrical surface  105  in such a manner to allow light to escape through one or more windows  110 . Thus, it is desirable to direct as much light as possible to cylindrical surface  105  to obtain maximum light emitted via windows  110 .  110 . Although the cylindrical surface  105  includes one or more windows, it should be understood that any type of surface may be utilized and may not include windows. 
         [0021]    However, as noted previously, device  102  may include functional or structural components such as PCBs that may impede light generated by a light source. For example,  FIG. 1   c  depicts a portion of a device  102  including the portion shown in  FIG. 1   b  but also including battery compartment  115 , which houses batteries. The batteries may power a light source such as an LED (“Light Emitting Diode”) not shown in  FIG. 1   b  or electronic components, on a PCB for example, that perform some functions on device  102  such as control of the LED or entertainment functions. The device may further include switch  120  to control powering of lighted device  102 . 
         [0022]    Although a PCB obstruction has been described, it should be understood that the structures and methods described herein may be utilized to provide for the propagation of light around any type of obstacle or obstruction regardless of character, composition or shape and thereby provide uniform illumination of a cavity such as a cylindrical cavity. 
         [0023]      FIG. 2  depicts an interior portion of an exemplary device that includes an optical waveguide for directing light around internal components and to provide uniform illumination of a cylindrical surface housing the device. In particular,  FIG. 2   a  shows a portion of device  102  with cylindrical surface  105  removed.  FIG. 2   a  thus shows battery compartment  115 , PCB  220 , LED  205 ( 1 ), LED  205 ( 2 ), LED leads  210 ( 1 ), LED leads  210 ( 2 ) and optical waveguide  215 . 
         [0024]    Battery compartment  115  may house batteries for providing power to device  102  such as LED  205 ( 1 ), LED  205 ( 2 ) and PCB  220 . Leads  210 ( 1 ) and  210 ( 2 ) may provide power respectively to LED  210 ( 1 ) and LED  210 ( 2 ) as well as controlling the functions of those LEDs. LED  205 ( 1 ) may be directly coupled to optical waveguide  215  for directing light for uniform illumination of cylindrical shell Although  FIG. 2   a  only shows a single optical waveguide  215  for receiving light generated by LED  205 ( 1 ), it is understood that device  102  may include a second optical waveguide  205 ( 2 ) for receiving light from LEDs  205 ( 2 ). 
         [0025]    According to one embodiment, optical waveguide  215  is configured in an aspherical shape. Further, according to this embodiment, optical waveguide may include a first and second layer comprising an internal and external layer. The internal and external layers may be composed of any materials allowing high transmission materials. For example, according to one embodiment, the internal layer may comprise a smooth layer of polycarbonate. The external layer may also comprise a rough layer of polycarbonate to allow light propagating from the internal layer to escape through the cylindrical surface  105  via windows (e.g.,  110  in  FIG. 1   a ). As noted, optical wave guide  215  may be composed of polycarbonate material. However, other materials such as acrylic plastic materials are possible. 
         [0026]    According to one embodiment, the optical waveguide may be treated with colorants and/or diffusers. For example, diffusers may be utilized in order to provide more uniform lighting. 
         [0027]    A direct input coupling geometry may be used for coupling respective LEDs  205 ( 1 ) and  205 ( 2 ) to optical waveguides  215 . A direct input coupling geometry couples light directly from a light source such as an LED by placing an emitting surface of the light source (e.g., LED) as close to the input surface of the light pipe as practically possible while avoiding any intermediate steps. 
         [0028]    Although the subject matter has been described in language specific to the structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features or acts described above are disclosed as example forms of implementing the claims.