Patent Publication Number: US-2003223210-A1

Title: Modular LED circuit board

Description:
FIELD OF THE INVENTION  
       [0001] The invention relates generally to modular LED circuit boards for use in constructing LED signs and displays and general illumination.  
       BACKGROUND OF THE INVENTION  
       [0002] LED displays are finding application in a variety of products. Display signs, advertising signs and lighting fixtures are a few examples. A majority of these LED displays use a plurality of LEDs mounted on a circuit board. For a majority of applications, each LED display requires a custom LED circuit board. As can be appreciated, the costs of manufacturing custom circuit boards can be quite high. To overcome the high cost of manufacturing custom LED boards, one approach has been to build LED displays from a plurality of modular LED boards. This approach does reduce the cost of manufacturing a LED display; however, this still requires the step of assembling a plurality of smaller LED boards to form a display. In some cases, the cost of assembling a suitable frame to mount the smaller LED boards may be as great as manufacturing a custom board. A modular LED board which is more versatile is therefore required.  
       SUMMARY OF THE INVENTION  
       [0003] In accordance with the present invention, there is provided a modular LED circuit board consisting of a circuit board being frangible along a first and second set of intersecting fragmentation lines, the fragmentation lines dividing the circuit board into a plurality of sections. A plurality of LEDs are mounted to the circuit board, at least one LED being mounted to each section, each section having a sub-circuit operatively coupled to the LED, each sub-circuit having a positive and negative lead.  
       [0004] With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the preferred typical embodiment of the principles of the present invention. 
     
    
    
     DESCRIPTION OF THE DRAWINGS  
     [0005]FIG. 1. is a perspective view of a circuit board made in accordance with the invention.  
     [0006]FIG. 2. is a perspective view of the circuit board shown in FIG. 1 which has been fragmented into several fragments in accordance with the invention.  
     [0007]FIG. 3. is a top view of a circuit board made in accordance with the invention.  
     [0008]FIG. 4. is a top view of a fragment of the circuit board shown in FIG. 3.  
     [0009]FIG. 5. is a top view of a section of the fragment shown in FIG. 4 showing the sub-circuit.  
     [0010]FIG. 6. is a side view of the section shown in FIG. 5.  
     [0011]FIG. 7. is a schematic view of the circuit of the circuit board shown in FIG. 3. 
    
    
     [0012] In the drawings like characters of reference indicate corresponding parts in the different figures.  
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] Referring firstly to FIGS. 1 and 2, the present invention is a modular LED circuit board, shown generally as item  10  which consists of a circuit board  12  which is frangible along intersecting fragmentation lines  14  and  16 . Fragmentation lines  14  and  16  divide circuit board  12  into a plurality of modules  18 . Each module  18  has LED&#39;s  20  mounted thereto. Preferably, circuit board  12  comprises a standard pre-printed circuit board. Fragmentation lines  14  and  16  may be either deep score lines or perforation lines.  
     [0014] Preferably, fragmentation lines  14  and  16  are arranged at right angles to each other such that modules  18  are rectangular. By arranging fragmentation lines  14  and  16  in a grid, board  12  may be broken into smaller fragments of various sizes and shapes. In the example illustrated in FIG. 2, board  12  has been broken into fragments  22 ,  24 ,  26 ,  28 ,  30 ,  32 ,  34  and  36  by breaking the board along the fragmentation lines. The smallest of these fragments,  26 , is only the size of one module  18 . Each of these fragments will have at least one LED mounted thereon.  
     [0015] While the particular arrangement of fragmentation lines illustrated in the drawings results in rectangular modules, it will be appreciated that any pattern of intersecting fragmentation lines may be used depending on the desired shape of the resulting modules. By selecting an appropriate pattern of intersecting fragmentation lines, square and even triangular modules may be created.  
     [0016] Referring now to FIG. 3, each module  18  has two LED&#39;s  20  mounted thereon. Any suitable LED or LED die may be used, however, surface mount LEDs are particularly useful. Each module  18  has a sub-circuit (see FIG. 5) operatively coupled to LED&#39;s  20 . The sub-circuit has positive leads  40  and negative leads  42 . Supplying a suitable electric current to leads  40  and  42  will cause LED&#39;s  20  to glow. Leads  40  and  42  of adjacent modules  18  are operatively coupled to each other such that when a suitable electric current is supplied to any pair of leads  40  and  42 , all of the LED&#39;s on board  12  will glow.  
     [0017] Referring now to FIG. 4, a board fragment  13  is shown having a plurality of rectangular module  18 . Each section  18  is rectangular and has opposite ends  44  and opposite sides  46  formed by fragmentation lines  16  and  14 , respectively. The corners of sections  18  are formed from cross shaped apertures  48 . Fragmentation lines  14  are basically perforated lines formed of apertures  50  and apertures  48 . Likewise, fragmentation lines  16  are formed from apertures  52  and apertures  48 . Adjacent sections  18  are connected together along opposite sides  46  by bridges  54 . Likewise, adjacent modules  18  are connected together along opposite ends  44  by bridges  56 . Each module  18  is provided with at least one positive lead  40  positioned at each end  44  and each side  46 . Likewise, each module  18  is provided with at least one negative lead  42  positioned at each end  44  and each side  46 . Hence, each module  18  will have four positive and four negative terminals. Providing four positive and negative terminals on each module greatly increases the flexibility of each module, since it can be supplied with electrical power from any side or end.  
     [0018] Leads  40  and  42  extend across bridges  54  and  56  such that the leads of adjacent modules  18  are electrically coupled to each other. Hence, suppling any positive and negative lead on board fragment  13  with an appropriate current will cause all of the LED&#39;s on the fragment to light. Board fragment  13  can be broken into still smaller fragments by breaking the board along one or more fragmentation lines. When fragment  13  is broken along a fragmentation line, the bridges linking adjacent rectangular modules  18  are broken, and the leads which cross those bridges are separated. For example, if sections  19 ,  21  and  23  are to be broken off to form a separate fragment, fragment  13  is broken along fragmentation line  16 A to break bridges  56 . Sections  19 ,  21  and  23  forming the smaller fragment will still be linked together by bridges  54 . Since bridges  54  will be intact, supplying power to any negative terminal  42  on fragment  23  and any positive terminal  40  on fragment  19  will cause all the LED in the smaller fragment to light up.  
     [0019] Apertures  48  are dimensioned and configured to receive a mounting screw (not shown) to permit the fragment to be easily mounted to a suitable housing by attaching the fragment to the housing via a plurality of mounting screws. Fragment  13  also has apertures  73  positioned between adjacent modules  18  and apertures  71  positioned at the center of each module. Apertures  73  and  71  are likewise dimensioned to receive a mounting screw. Apertures  48  are positioned along fragmentation lines  16  and  16 A while apertures  73  are positioned along fragmentation lines  14 . Hence apertures  48  and  73  act as both a mounting mechanism and also as part of the fragmentation lines.  
     [0020] Referring now to FIGS. 5 and 6, each rectangular module  18  will have a sub-circuit  58  printed onto board material  12 . Sub-circuit  58  will generally comprise conductors  60  and  62  which are part of a layer of conductive material embedded in board material  12  which was etched with a suitable circuit pattern. Conductor  60  is laid out such that it electrically couples all of the positive leads  40  together. Conductor  60  also connects to the positive sides of both LEDs  20 . Likewise, conductor  62  is laid out such that it electrically couples all of the negative leads  42  together and the negative sides of both LEDs  20 . Preferably, conductors  60  and  62  are made as thick as possible in order to act as a heat sink for LED&#39;s  20 . A resistor element  64  may be incorporated into circuit  58  in order to limit the current flowing through LED&#39;s  20 . A suitable resistor can be selected depending on the current and voltage rating of the LEDs  20  and the desired amount of luminous flux. Each module  18  will be provided with aperture  71 , which is dimensioned and configure to receive a mounting screw or bolt. Aperture  71  ensures that each module  18  can be easily mounted to what ever housing is desired.  
     [0021] As mentioned previously, preferably, sections  18  are electrically coupled to each other in a parallel circuit such that supplying all the LEDs with current can be achieved by supplying current to any pair of positive and negative leads. A suitable circuit diagram is shown in FIG. 7. Each section  18  has a sub-circuit  66 . Sub-circuits  66  of adjacent sections  18  are electrically coupled together in parallel to from a larger circuit  68 . Larger circuit  68  may be supplied with electrical power via terminals  70 . It will be appreciated that FIG. 7 represents a schematic representation of the entire circuit of LED&#39;s on board  12 . Terminal  70  corresponds to terminals  40  and  42  of each module  18  (see FIG. 6).  
     [0022] Referring back to FIGS. 1 and 2, a user can start with LED circuit board  12  to form numerous circuit board fragments of useful size and shape. For example, if the user wishes to create an “L” shaped LED circuit board in order to manufacture a portion of an advertising display sign, the user can simply break board  12  along fragmentation lines  14  and  16  to create fragment  22  having the desired shape. Various sizes and shapes of circuit board fragments can be created simply by breaking the circuit board along the appropriate fragmentation lines. Each of the resulting fragments can be easily wired up to a suitable power source to form a functioning LED module. The current and voltage will depend on the number of LEDs on the fragment.  
     [0023] A specific embodiment of the present invention has been disclosed; however, several variations of the disclosed embodiment could be envisioned as within the scope of this invention. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.