Abstract:
An article of manufacture includes a jig including a flat surface with a curved groove therein; a light guide located within the curved groove, the light guide including an internal groove; and a bend-aid located in the internal groove of the light guide.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to methods and apparatuses for bending light guides for guiding light emitted by light emitting diodes (LEDs). 
         [0003]    2. Description of the Related Art 
         [0004]    Glass tubes filled with neon gas have been used to provide decorative, colored lights. For example, U.S. Pat. No. 5,001,613 describes a housing to protect neon tube lights. This is necessary because the glass tubes are fragile. Further, neon tube lights are difficult and costly to manufacture. Finally, neon tube lights consume a significant amount of power, and thus are costly to keep lit. Accordingly, alternative decorative lighting devices were desired. 
         [0005]    The invention of LEDs allowed a low cost alternative to neon lighting. With regard to the power consumed, LEDs consume only 10% or less of a comparable neon tube light. However, the light from an LED needs to pass through a light guide to provide the same effect as a neon tube. To provide the same versatility as neon tubes, the light guides need to be able to be formed into a plurality of shapes, especially lettering. Conventionally, this has been done by heating a plastic light guide with a heat gun and then bending the hot light guide. However, this process is time consuming, difficult to repeat, and cannot provide light guides with a radius of curvature comparable to neon tubes. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention broadly comprises a method and apparatuses for bending LED light guides. In one embodiment, an article of manufacture includes a jig including a flat surface with a curved groove therein; a light guide located within the curved groove, the light guide including an internal groove; and a bend-aid located in the internal groove of the light guide. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
           [0008]      FIG. 1  shows a desired pattern for a lighting unit including LED light guides according to the present invention; 
           [0009]      FIG. 2  shows a jig used to bend LED light guides; 
           [0010]      FIG. 3  shows a bend-aid being inserted into a light guide according to the present invention; 
           [0011]      FIG. 4  shows the cross sections of an exemplary bend-aid and light guide; 
           [0012]      FIG. 5  shows the combined bend-aid and light guide being heated in an oven; 
           [0013]      FIG. 6  shows the heated combined bend-aid and light guide being inserted in grooves of the jig; 
           [0014]      FIG. 7  shows the bend-aid being removed from the light guide while the light guide remains in the jig; 
           [0015]      FIG. 8  shows an LED being inserted into the light guide; 
           [0016]      FIG. 9  shows the completed lighting unit; 
           [0017]      FIG. 10  shows a perspective view of an oven according to one embodiment of the present invention; 
           [0018]      FIG. 11  shows a top view of an oven according to one embodiment of the present invention; 
           [0019]      FIG. 12  shows a front view of an oven according to one embodiment of the present invention; and 
           [0020]      FIG. 13  shows a side view of an oven according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. 
         [0022]    The present invention includes a method and apparatuses for bending LED light guides. An exemplary method for bending LED light guides will now be explained with reference to  FIGS. 1-9 . 
         [0023]      FIG. 1  shows a pattern  10  for a desired lighting unit. The pattern includes lighting portions  12  which will be made of LED light guides with LEDs installed therein. Based on the pattern, a jig  20 , shown in  FIG. 2 , is created. Jig  20  includes grooves  22  which correspond to the lighting portions  12  of the pattern  10 . In one embodiment, grooves  22  are cut with a router in a surface such as a 0.75 inch thick board, and have a width slightly greater than the desired LED light guide. In one embodiment, the LED light guides are 19/32  inches wide. 
         [0024]    The LED light guides are cut to be the same length as grooves  22 . According to the present invention, grooves  22  may have a radius of curvature as small as 5/8  inches. In contrast, using a heat gun can only achieve a minimum radius of curvature of 1.25 inches. This allows light guides in the shapes of letters or numbers having a font size of approximately 10 inches tall to be created in accordance with the present invention. This is a dramatic improvement over letters or numbers made with a heat gun, which need to be at least 18-20 inches tall due to the greater minimum radius of curvature. 
         [0025]    As shown in  FIG. 3 , bend-aid  32  is inserted into the internal groove in LED light guide  34 . As shown in  FIG. 4 , bend-aid  32  is approximately the size of the groove in LED light guide  34 . In one embodiment, bend-aid  32  is 13/32  inches wide and 7/16  inches tall. In this embodiment, the groove in LED light guide  34  has these same dimensions. The bend-aid  32  may have the same length as LED light guide  34 , or may include multiple bend-aids  32  such that substantially the entire groove in LED light guide  34  is occupied by a bend-aid  32 . 
         [0026]    As shown in  FIG. 4 , LED light guide  34  has a U-shape. In the embodiment shown in  FIG. 4 , the thickness of a bottom portion of the U is greater than the thickness of the arms of the U. In one embodiment, the thickness of the bottom portion of the U is 17/64  inches and the thickness of the arms of the U is 3/32  inches. Also as shown in  FIG. 4 , in some embodiments the bottom portion of the light guide  34  is curved. In other embodiments, the bottom may be flat. 
         [0027]    Also, in some embodiments the light guide  34  is made of plastic and the bend-aid  32  is made of silicone. The bend-aid  32  provides support to the walls of light guide  34  when the light guide is being bent so that the internal groove of the light guide does not deform or collapse due to the bending. 
         [0028]    As noted above, bend-aid  32  is inserted into the groove in light guide  34  such that substantially the entire groove is filled with bend-aid  32  to form a combined bending element  42 . As shown in  FIG. 5 , combined bending element  42  is then placed in an oven  100 . In one embodiment, oven  100  is maintained at 325° F., and combined bending element  42  is heated in the oven for 15 minutes. In the embodiment shown in  FIG. 5 , the flat portion of the combined bending element  42  is placed down, such that the bend-aid  32  is facing the shelf of the oven  100 . 
         [0029]    After combined bending element  42  is heated for a sufficient period of time, it is removed from oven  100 . As shown in  FIG. 6 , combined bending element  42  is then placed into groove  22  of jig  20 . In the embodiment shown in  FIG. 6 , combined bending element  42  is inserted such that the flat portion of the combined bending element  42  is facing up. After combined bending element  42  cools for a period of time, bend-aid  32  is removed from the groove in light guide  34 , as shown in  FIG. 7 . Light guide  34  is not removed from groove  22  at this time. After a further cooling time, light guide  34  is removed from groove  22 . 
         [0030]    As shown in  FIG. 8 , LED  52  is then inserted into the groove in light guide  34  to create lighting element  90 . As shown in  FIG. 9 , lighting element  90  is then installed onto the lighting fixture. 
         [0031]      FIGS. 10-13  illustrate an oven  100  used with the invention. Oven  100  includes a door  130 , shelves  120  to support the combined bending elements  42 , and control electronics  110 . The control electronics  110  may include a proportional/integral/derivative (PID) controller to maintain the oven temperature at a set level. As noted above, in one embodiment the temperature is set at 325° F. Oven  100  also extends a length much greater than its width or height. In one embodiment, oven  100  is 8.5 feet long. In this exemplary embodiment, an upper shelf is 4 11/16  inches wide and a lower shelf is 3.5 inches wide. The upper shelf is set 2.125 inches from the bottom of the oven in the lower shelf is set 1 inch from the bottom of the oven. The oven has a circular cross-section with a diameter of 4.625 inches. 
         [0032]    Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.