Abstract:
A method and system for attaching LEDs to circuitry which would protect the LEDs from heat damage and allows for individual LEDs to be replace when a LED fails, without a significant increase in manufacturing cost.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable  
       BACKGROUND OF INVENTION  
       [0004]     In the past LEDs were mainly use as status indicator lights in electronics, but with the vast improvements in technology—increasing the efficiency and the lifespan while reducing cost—LEDs have been put to many more uses. Multiple LEDs can easily be assembled together into an array, by soldering the LEDs together into a circuit, which can then be use to replace fluorescent lights and incandescent light bulbs, as respectively shown by U.S. Pat. No. 6,762,562 “Tubular housing with light emitting diodes” and U.S. Pat. No. 6,580,228 “Flexible substrate mounted solid-state light sources for use in line current lamp sockets”. LED arrays can be put to multitude of lighting uses given the major advantage of the long life span of LEDs and the minimal shift in color temperature thru the life of the LEDs. The LEDs currently available usually have a lifespan of 50,000 hours and some with a lifespan well over 100,000 hours.  
         [0005]     There is little doubt that the lifespan and efficacy of LEDs will only increase as the technology improves. Unfortunately there is no guarantee that every LED is manufactured flawlessly and assembled without damage into a circuit such as the light array. LEDs may fail prematurely largely due to damage caused during the soldering process used to attach most LEDs to circuitry, because of the LED being sensitive to the heat needed to liquefy the solder. A solution to prevent the heat damage would be to use a mechanical process to attach the LEDs such as clamping the leads to the circuitry. However this clamping method of attachment will make production of these LED arrays more complex due to clamping forces required, the small size of the LEDs and tight packing of the LEDs needed to achieve a sufficient light output by the array. Some mechanical methods are taught in U.S. Pat. No. 5,404,282 “Multiple Light Emitting Diode Module” but the spacing between the adjacent LEDs is fairly large due to the clearance needed for the mechanical methods of attachment. The tight packing needed to produce a high light output will not be possible with the mechanical methods. Also the LEDs are permanently attached to its circuitry. This need for a high density of LEDs in combination with the shape of the array can even make soldering a difficult process as seen in the methods utilized in U.S. Pat. No. 6,762,562 and U.S. Pat. No. 6,580,228 Both patents teach of soldering LEDs onto a flexible flat circuit board/substrate and then bending the circuit board/substrate with the attached LEDs into its final desired shape. The need for the flexible circuit board/substrate is due to the tight spacing of the final shape, making it impossible to solder the LEDs on to a circuit already in the final shape. Unfortunately the flexible circuit board/substrate would be very fragile due to thinness of the circuit board needed to achieve the flexibility. The handling and process of bending the array into the final shape can easily break the electrical circuit, solder joins or LEDs given the thin circuit board/substrate and the heavier bulk of the attached LEDs and solder. The thinness of the electrical circuit would also have a higher resistance hence heating up and along with the heat generated by the LEDs can cause the electrical circuit attached to the bent substrate to expand at different rates, hence pulling it apart. This heating cause by the circuit and LEDs through normal usage and cooling when the array is off can greatly reduce the life of the light array, warping the shape and stressing the circuitry. The flexible circuit board/substrate may also delaminate and crack due to the characteristic differences of the materials and the constant stress caused by the bending. Also the risk of heat damage to LEDs during the soldering process is still not eliminated. The LED assembly process currently known in the art is very limiting in what can be constructed and the arrays that can be constructed may not be very sturdy.  
         [0006]     Yet another problem is when a single LED does fail in a light array—due to heat damage during assembly or production flaw in the LED package—there is currently no easy way to replace just that single defective LED. This usually meant putting up with having one or more blacked out spots in the light array until there are enough individual LED failures to warrant replacing the entire array. This problem with the LED array is neither pleasing to look at, nor very cost effective given the remaining unused lifespan of the still functional LEDs within the array that must be discarded if the array is to be replaced. These reasons and the difficulty of manufacturing the arrays has hampered the wide spread use of LED array based lighting by consumers. Hence a need has been recognized for a method to simplify and improve the process of attaching LEDs to circuitry and allows for easy replacement of faulty LEDs, or other small high efficiency lights, such as OLEDs, PLEDs, etc which hence fore will be referred to as a LED. One can try simply plugging the LED leads in to a breadboard type circuit but the leads need to be sufficiently long to ensure good contact for electrical and thermal conduction. Unfortunately long LED leads are easily bent and will be difficult to insert into the breadboard. The breadboard itself is also costly to manufacture due to the complex circuitry and contacts, and is of limited life as the insertion and removal can wear and loosen the contacts in the breadboard. Hence to ensure a good electrical contact and good heat dissipation the LEDs leads are currently still mostly solder or mechanically clamped permanently to its power circuitry due the small surface area of the leads and difficultly of maintaining a good contact between the lead and the circuit. Another solution currently being used is to assemble a couple of LEDs which maybe of several colors in to a single smaller module, which is then assembled into larger arrays. The modules are replaceable, but not the individual LEDs within the modules. Unfortunately these units are relatively costly to manufacture, cannot achieve the same density of LEDs as with the array of individual LEDs and are still susceptible to the damage cause during assembly of the LEDs into the module circuit. Also the discarding of perfectly functional LEDs within a flawed module when being replace is still not avoided, wasting perfectly usable LEDs. A better solution for attachment and connection of LEDs to circuits, which would enable replacement of individual broken LEDs, while minimizing cost is still needed.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     I propose utilizing the LED leads themselves to create a pair of prongs with a spring-mechanism allowing for easy attachment and removal of the LED from circuitry and a method to increase the contact area of these prongs. The invention involves modifying the leads of the LED itself such as bending and folding or flattening and folding the leads. Hence increasing the usability of the LEDs by making them easier to attach to circuitry while minimizing the increase in manufacturing cost. The current LED-manufacturing process would remain unchanged unlike that of U.S. Pat. No. 6,541,800, which also teaches of a method of heatless attachment. The method shown in U.S. Pat. No. 6,541,800 utilizes a “RCA-type plug” that involves a whole new manufacturing process, which would involve major retooling of current manufacturing lines and render useless current manufacturing capacities. The primary embodiment of the present invention would involve simple subsequent modification of the leads of the LEDs to create a pair of prongs with a spring mechanism and then adding some type of encasement to better secure the contact prongs from forces caused during insertion and unplugging of the LED to its circuitry. Hence current LED-manufacturing capacities can still be utilized.  
         [0008]     A benefit of the present invention is that the LED array circuitry can be kept very simple involving one or more pairs of parallel electrical and thermal conductive channels, which may hold multiple LEDs. Whereas the circuitry of U.S. Pat. No. 6,541,800 would be more complex due to the “RCA-type plug”, where the anode surrounds the cathode making a flat single layer circuit layout impossible, since the electrical paths will have to overlap to make a connection with the cathode that&#39;s encircled by the anode.  
         [0009]     Besides the benefits described above, several objects and advantages of the present invention are specifically:  
         [0010]     Low cost modification without the need to change existing manufacturing processes, since no new parts are introduced, so existing production facilities can be used.  
         [0011]     This method of attachment to circuitry eliminates the chance of heat damage to the LED that can occur when the LED are soldered.  
         [0012]     Reduced cost of replacement since just those non-functional LEDs are replaced instead of an entire array of LEDs.  
         [0013]     A very flexible design of this invention allows the user to easily alter the lighting array color by swapping in different color LEDs without the need of any specialized tools.  
         [0014]     The invention would also allow consumers to configure the LED lighting array as illuminated signs by removing and rearranging the LEDs to create an image.  
         [0015]     LEDs have been around for decades but haven&#39;t really taken off in the consumer market. The present invention will hopefully help expand the use of LEDs to replace other lighting. LED save energy compared with incandescent and protect the environment compared with fluorescent, which contain mercury. Further objects and advantage of my invention will become apparent from a consideration of the diagrams and ensuing description. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0016]      FIG. 1  shows an isometric view of a LED before modification.  
         [0017]      FIG. 2   a,    2   b,  and  2   c  shows isometric views of some stages involved in manufacturing the LED of the first embodiment.  
         [0018]      FIG. 2   d  shows a cross section of the LED and its base socket in the first embodiment and how the LED attaches to its socket.  
         [0019]      FIG. 3   a  and  3   b  shows isometric views of some stages involved in manufacturing the LED of the second embodiment.  
         [0020]      FIG. 3   c  shows a cross section of the LED and its base socket in the second embodiment and how the LED attaches to its socket.  
         [0021]      FIG. 4   a  and  4   b  shows isometric views of some alternative embodiments.  
         [0022]      FIG. 4   c  shows a cross section of an alternative embodiment with LED&#39;s leads modified before manufacture.  
         [0023]      FIG. 5  shows an isometric view of another type of LED package and stages involved in this alternative embodiment.  
         [0024]      FIG. 5   y  shows two orthographic views of another type of LED package. The top view shows the original LED and the bottom view shows the modified LED according the present invention.  
         [0025]      FIG. 5   z  shows two orthographic views of yet another type of LED package. The top view shows the original LED and the bottom view shows the modified LED according the present invention.  
         [0026]      FIG. 6  shows an exploded isometric view of a LED base socket rotated 180 degrees from that of the cross section in  FIG. 3   c    
         [0027]      FIG. 7  shows an isometric view of an alternative LED base socket with separated individual contact channels.  
         [0028]      FIG. 8  shows an isometric view of an alternative LED base socket shape and layout.  
         [0029]      FIG. 9  shows an isometric view of another alternative LED socket shape and layout.  
         [0030]      FIG. 10  shows an isometric view of a conventional circuit board modified for attachment of the LED of this invention.  
         [0031]      FIG. 11  shows an electrical bridge that can be used to connect portions of the circuit.  
         [0032]      FIG. 12  shows a light array utilizing LEDs. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     A common LED is shown in  FIG. 1  before any modification with a pair of leads both an anode and a cathode denoted by  102  and a LED package denoted by  101 . In the preferred embodiment the LED  101  has both its leads  102  flattened to increase its surface area as shown by  FIG. 2   a  both the flattened anode and cathode leads are denoted by  202   a.  The leads are then folded as denoted by  202  in  FIG. 2   b  to form a pair of spring prongs. The folds in prongs  202  allows for some give or compression that helps ensure sufficient contact with a corresponding socket without having to manufacture the prongs nor its corresponding socket to very tight tolerances hence minimizing the cost of manufacturing and assembly. The pair of prongs  202  can then be further secured by adding some type of encasement denoted by  203  right below the base as in  FIG. 2   c  the entire finished LED is denoted by  200 . The encasement  203  can be mold on using plastic, resin, or other materials or pre-made in halves and snapped or glued into placed. A notch can be molded into encasement  203 , as better shown in  FIG. 2   d  a cross section of encasement  203 . The notch in  203  can be used to distinguish the polarity. Still referring to  FIG. 2   d  it can be seen that the pair of prongs  202  has also been bent outward to increase the space between the two prongs. Also shown in  FIG. 2   d  is a portion of the corresponding base socket denoted by  211  that can be form from plastic or a ceramic that provides better thermal conduction while electrically insulating. The pair of electrically conductive u-channels denoted by  212  forms the sockets, which the pair of spring prongs  202  plugs into. The pair of u-channels  212  can be static given that the pair of spring prongs  202  will compress to fit into the u-channels  212 , so that the fit of one LED  200  will not affect the fit of an adjacent LED  200  even if the LEDs  200  or base socket  211  are not manufactured perfectly to precise tolerances. If a spring or clamping mechanism for LED attachments were put into the base socket in place of the pair of spring prongs  202 , a much more complex and expensive base socket  211  would be needed to achieve the same fit tolerances as the LED of the present invention. A polarity alignment tab as denoted by  213  in  FIG. 2   d  matches up with the notch in encasement  203  to ensure that the LED prongs  202  can only be plugged in to the base socket  211  one way. Further more a locking mechanism can be implemented through the addition of a ridge denoted by  204  in  FIG. 2   d  that fits into groove denoted by  205  when the LED  200  is mated with the base socket  211 . Hence the LED  200  will simply snap securely into place when plugged into the base socket  211  making the assembly process very easy.  
         [0034]     An alternative embodiment would not involve flattening the leads but requires multiple bends in order to increase the contact surface area as shown in  FIG. 3   a.  The leads have multiple folds to create a pair of spring prongs denoted by  302 . The prongs  302  are folded in such a manner to increase the surface area in the contact planes while reducing the length of the prongs to an optimal size, so that the prongs won&#39;t be easily damaged—such as accidentally being bent—when being inserted or removed. This embodiment also uses an encasement denoted by  303  in  FIG. 3   b  and  FIG. 3   c.  Encasement  303  serves the same function as encasement  203  in the previous embodiment to make the pair of spring prongs  302  sturdier. The whole LED is denoted by  300 .  FIG. 3   c  shows the cross section of this embodiment and a portion of its corresponding base socket  311 , which contains a pair of conductive u-channels denoted by  312  that fits with the pair of spring prongs  302  and a polarity alignment tab denoted by  313  that matches up with the notch in encasement  303 . An alternative to the notch in encasement  303  and polarity alignment tab  313  the anode prong and cathode prong themselves can also be made to different thicknesses along with their corresponding sockets, so that it is easy to distinguish between the anode and cathode, although not drawn it is easily understood by anyone skilled in the art.  
         [0035]     Some other embodiments are shown in  FIG. 4   a,    FIG. 4   b,  and  FIG. 4   c.  The pair of spring prongs denoted by  402   a  of  FIG. 4   a  are similar to the pair of prongs  202  of the first embodiment, but has only the outer sides of the leads flatten in so that the inner surface of the two prongs  402   a  are flush, whereas prongs  202  in the first embodiment has uneven inner surfaces. The pair of spring prongs denoted by  402   b  in  FIG. 4   b  are similar to the prongs  302  of the second embodiment but has fewer bends, which makes the fabrication simpler therefore reducing the cost of manufacturing. Both  402   a  and  402   b  can also be secured further by encasing the prongs partially in the same way as  203  and  303  in the first and second embodiments.  FIG. 4   c  shows a cross section of alternative embodiment where the LED leads are modified as denoted by  402   c  similar to prongs  402   a  before the production of the LED. The modified leads  402   c  are used in the manufacture of the LED, where by the LED manufacturing process secures prongs  402   c  without the need for the additional encasement  203  of the first embodiment. However this would involve the retooling of the LED production line itself, although relatively minor as compared with U.S. Pat. No. 6,541,800, since only the dimension of the lower portion of the leads  102  are modified leaving the rest of the LED the same. The benefit of this is lower long run production cost, but higher initial cost due to retooling. This would be the preferred embodiment if production volume were large enough to justify the retooling. As with most new technology initial volume will be low and gradually increase so a lower starting cost would be desirable as with the post-modification of the first embodiment. However as volume increase to a critical level it would better and cheaper on the long run to modify the lead before manufacture of the LEDs. The leads both the anode and cathode could also be manufactured with thicker material and bent similar to prongs  402   c  if the retooling route is chosen. The benefit of thicker leads is better heat dissipation, which wasn&#39;t possible previously because the attachment process would have damaged the LED die if a thicker lead is soldered, transferring a lot more heat to the LED die.  
         [0036]     Other LED packages can also be modified to be used in the same way.  FIG. 5  shows some steps in creating spring prongs using a different LED package. The original LED is denoted by  502   a.  The flattening of the leads as denoted by  502   b  is done to lengthen the leads so that the leads can then be bent down as denoted by  502   c  to create a sufficiently long prong. The pair of leads is then folded over to create a spring mechanism forming a pair of spring prongs as denoted by  502   d  that can be plugged into a socket similar to the preceding embodiments.  FIG. 5   y  shows two orthographic views of another LED package the upper view is the original LED and the lower view shows how the LED has been modified in the practice of the present invention.  FIG. 5   z  shows another two orthographic views of yet another possible LED package to be used in the practice of the present invention the upper view is the original LED and the lower view shows the modified LED. The position at which the leads are folded and the direction—the ends folded towards the center or away from the center—should not be construed as limiting the present invention. Other LED packages can also be modified to be used in the practice of the present invention and the type of LED is not to be limited to only those shown.  
         [0037]     An exploded isometric view is shown in  FIG. 6  of a portion of the base socket  311  and the pair of electrically conductive u-channels  312  one positive and the other negative into which prongs  302  are inserted. Multiple LEDs can be install in the pair of u-channels  312  and multiple pairs of u-channels  312  can be used utilized to form the entire base socket. A base socket  1211  with multiple pairs of u-channels and multiple LEDs  200  installed in those u-channels is shown fully assembled in  FIG. 12 . Shown in  FIG. 7  is a base socket  711  with a polarity alignment tab denoted by  713  and separated individually addressable u-channels/socket pairs denoted by  712 . The base sockets  311  shown above has parallel channels able to hold multiple LEDs in parallel to keep the base circuitry simple, but the LED of the invention can also be used with an array base sockets where each socket pair holds a single LED or group of LEDs where each socket pair is individually addressable like that of socket pairs  712 . The individualized socket pairs  712  would allow for individual LEDs to be turn on or off independent of the other LEDs in the array.  
         [0038]     A full circular base socket denoted by  811  is shown in  FIG. 8  without the polarity alignment tab. The base socket  811  has three pairs of electrical u-channels or tracks denoted by  812  laid out concentrically. The voltage and amps used by this base socket  811  can be manipulated by how the three pairs of u-channels  812  are wired—in parallel or series—and by the LED voltage and current requirements. The u-channels  812  can be laid out more tightly than illustrated in the base socket  811 , and the electrical circuitry is kept very simple in the base socket  811  due to the attachment mechanism being in the prongs of the LED instead of the base circuitry. Yet another base socket is shown in  FIG. 9  this base socket denoted by  911  is a cylinder with three pairs of electrical u-channels/tracks denoted by  912  going around the cylinder. The u-channels  912  can also be laid out closer than illustrated and the cylinder of any diameter or length. The base socket can be created in any shape and size and wired in many ways not to be limited to the ones shown.  
         [0039]     The present invention would greatly simplify the construction of LED arrays of any shape and size not to be limited to those described above. For example the base circuit socket  91   1 , which will hold an array of LEDs, can be easily constructed. A mold of the desired shape will be needed in this case a hollow cylinder. The electrically conductive u-channel  912  will be shaped accordingly (rings) and laid out within the mold and wired into a circuit. The mold will be then injected with plastic or some other electrically insulating material, which will solidify and give structure to the circuitry laid out within the mold. Then the LEDs of this invention would be simply inserted into the finished base circuit socket thus minimizing the assembly operation and handling and hence the chances for damage of the LEDs during the manufacturing process. It would also be possible to have the desired shape machine milled or molded alone with paths for the u-channels and circuitry that will be added afterwards to the finished shape, but this method would be more labor intensive requiring that the electrically conductive u-channel be fitted into the corresponding milled/molded trough and the wired together to form a circuit. The base socket if machine milled can be made of any material, such as synthetics, glass and even metal, but with metal proper electrical insulation must be applied between the electrical u-channel and the metal base.  
         [0040]      FIG. 10  show of a conventional circuit board denoted by  1011  with pairs of electrically conductive rectangular grommet denoted by  1012  fitted into holes within the circuit board  1011  and solder to the circuitry. The pair of grommets  1012  allows for the LED  200  of the first embodiment to be attached and used with and conventional circuit board, while protecting the LED  200  from damage, since only the grommets  1012  are soldered and exposed to heat.  
         [0041]     The multiple pairs of u-channels  312  in the base socket  311  do not have to be electrically hard wire to each other into a circuit. Electrically conductive jumper/bridges denoted by  1118  in  FIG. 11  can be plugged into the u-channels  312  to form complete circuits between multiple pairs of u-channels  312 . In  FIG. 11 a  cross sectional view shows two separate jumpers  1118  connecting the three separate pairs of u-channels  312 . When a power source is connected to the left most and right most tracks with the LEDs  300  plugged into the pairs of u-channels  312  a completed circuit is formed with the jumpers  1118 . The benefit of this is that the circuit can easily be reconfigured. The jumpers  1118  can be a simple electrical conductor or contain some electrical regulating circuit such as a resistor to adjust for difference in power required between different pairs of u-channels  312 . A jumper utilizing a resistor is denoted by  1100 , although jumper  1100  is a different size than jumper  1118  they can be constructed with a resistor in the same way. Jumper  1100  contains a pair of electrically conductive spring prongs denoted by  1112  mounted on a non-conductive base denoted by  1111 . A resistor denoted by  1110  is soldered to the pair of prongs  1112  connecting the two prongs  1112  electrically. A single jumper  1100  can be used in place of a single LED  300  consuming the same electricity as LED  300  would, so that the array can contain lit and unlit area allowing patterns or images to be displayed while maintaining the electrical levels between multiple pairs of u-channels  312 . Thus allowing the consumer to create their own custom illuminated signs by rearranging the LEDs  300  within the base socket  311  and using the jumpers  1118  and resistor modules denoted by  1100  to regulate the electricity. Furthermore a flexible translucent tube sheathing clear or colored can be used to cover sets of LEDs to create lines to produce the effects of a neon signs.  
         [0042]     Although only a couple types of LED packages, methods of LED leads modification and array shapes have been described in detail above, it will be understood to those skilled in the art that, the present invention can be used with many different types of LED packages and that, the fabrication of the spring prongs can be done in many other ways too numerous go into detail. The shape of the base socket is also as numerous as whatever one can imagine. Many modifications and substitution not detailed in specification can be made without departing from the spirit and the scope of the invention.