Abstract:
A circuit board having improved soldering characteristics having raised structure consisting of spacer pads arranged to provide for vertical distancing of electrical or electronic components from the component side planar surface of the circuit board. Such spacing is complementary to top vented soldering stations where the spacing allows solder process gases to flow unimpeded from the soldering stations through the spacing to atmosphere.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     None. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is for a circuit board, and more particularly, is for a circuit board having improved soldering characteristics with respect to components which can be secured to a circuit board such as by soldering. 
     2. Description of the Prior Art 
     Prior art circuit boards often utilize wave soldering techniques to flow liquidized solder at a raised temperature along one surface or more of a circuit board to effect multiple solder joints between the soldering pads of the circuit board and the leads of one or more electrical or electronic components such as, but not limited to, a light emitting diode. Maintaining the quality of a suitable solder joint can be problematic in that a cold solder joint may be produced when solder cannot flow fully into the region of intended solder flow. Such a problem can be caused due to limited or non-existent gas flow and breathing within or above the region of intended solder flow, such as caused by the region of intended solder flow being a closed space having a pneumatic-like seal whereby solder flow cannot reach the region of intended solder flow, or if the solder does reach the region of intended solder flow, the heat is dissipated due to slow movement of the solder before sufficient heating of the solder joint takes place. Additionally, air or other gases trapped in the upper region of intended solder flow cannot be displaced by the solder flow, and a back pressure may build to impede the flow of solder therein. Clearly what is needed is a region of improved solder flow between a component lead and a circuit board to improve the quality of a solder joint such as is provided by the instant invention. 
     SUMMARY OF THE INVENTION 
     The general purpose of the present invention is to provide a circuit board having improved soldering characteristics. 
     According to one embodiment of the present invention, there is provided a circuit board having improved soldering characteristics having raised structure consisting of spacer pads arranged to provide for vertical distancing of electrical or electronic components from the component side planar surface of the circuit board to create a vented space between the planar surface of the circuit board and the body of an electronic component as well as a slightly increased size space at the solder station(s). The spacer pads, which can be of different forms, are located in close proximity about the regions where the components are to be located on the component side of the circuit board. One form of a spacer pad can be a stand alone spacer pad and another form can be a spacer pad juxtaposing a solder station, referred to as a terminal spacer pad because of its near location to the solder station or “terminal.” Regardless of the form of spacer pad, whether a stand alone spacer pad or a terminal spacer pad, the upper surface of each spacer pad projects a like distance above the planar surface of the circuit board to provide for component spacing from the planar surface of the circuit board. More importantly, such spacer pads raise the lower surface of the component above the levels of the solder stations so that venting is allowed and provided extending upwardly through the circuit board at the upper region of the circuit board at the solder stations. Such venting allows for escaping of gases through the upper regions of the solder stations to negate a vapor lock, thus allowing unimpeded flow of molten solder therein in a timely fashion to effect a proper solder joint. 
     One significant aspect and feature of the present invention is a circuit board having improved soldering characteristics. 
     Another significant aspect and feature of the present invention is a circuit board having spacer pads which are stand alone pads or terminal spacer pads juxtaposing solder stations. 
     Still another significant aspect and feature of the present invention is the use of spacer pads to provide a clear area at the upper region of the solder station for the clear passage release and unrestricted flow of gases upwardly during the soldering process, thus allowing solder flow unimpeded therein to effect a proper solder joint. 
     Yet another significant aspect and feature of the present invention is the spacing of components above the circuit board to increase cooling airflow around the undersides of the components. 
     Having thus described embodiments of the present invention, it is the principal object of the present invention to provide a circuit board having improved soldering characteristics. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
     FIG. 1 illustrates an isometric view of a circuit board having improved soldering characteristics, the present invention; 
     FIG. 2 illustrates a cross section view of the circuit board having improved soldering characteristics along line  2 — 2  of FIG. 1; 
     FIG. 3 illustrates a cross section view of a component soldered to the circuit board having improved soldering characteristics; 
     FIG. 4 illustrates a close cross sectional view of FIG. 3 along line  4 — 4  of FIG. 3; and, 
     FIG. 5, an alternate embodiment, illustrates a cross section view of a circuit board having improved soldering characteristics, having modified solder stations. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates an isometric view of a circuit board having improved soldering characteristics  10 , the present invention, also referred herein as the circuit board  10 . Clearly and readily viewable components or features of the circuit board  10 , shown in the illustration, include a substrate  12 , opposing stand alone spacer pads  14  and  16 , a terminal spacer pad  18  juxtaposing a solder station  20 , and a terminal spacer pad  22  juxtaposing a solder station  24 . An upper plastic mask  26  is applied to the upper surface of the substrate  12  and also overlies and forms the upper regions of the stand alone spacer pads  14  and  16  and the terminal spacer pads  18  and  22 , as later described and shown in detail. 
     FIG. 2 illustrates a cross section view of the circuit board having improved soldering characteristics  10  along line  2 — 2  of FIG.  1 . Stand alone spacer pad  14  is formed on the upper surface of the substrate  12  by an elongated foil member  28   a  such as an elongated circle or other suitably shaped form and an overlying raised plastic mask portion  26   a  of the upper plastic mask  26  having an upper surface  30  being above the upper surface of the general layer upper plastic mask  26 , that surface  30  upon which a lower surface of an electrical or electronic component can rest and be spaced. The stand alone spacer pad  16  of FIG. 1, having the same functionality as that of the stand alone spacer pad  14 , is formed in the same manner and fashion and is not described for purposes of brevity. The terminal spacer pad  18  is formed in the same manner as described for the stand alone spacer  14  on the upper surface of the substrate  12  by a truncated and suitably shaped elongated foil member  28   b  and an overlying raised plastic mask portion  26   b  of the upper plastic mask  26  having an upper surface  34  being above that of the general layer of the upper plastic mask  26 , that surface  34  upon which a lower surface of a component can rest and be spaced. The terminal spacer pad  18  juxtaposingly aligns to the upper region of the solder station  20 , generally referring to the solder station  20  being the region above, about and below a hole  38  extending vertically through the substrate  12 , and including hole  38 . The foil member  28   b  is partially devoid of any plastic mask material  26   b  in the upper region of the solder station  20  and extends about the upper region of and about the hole  38 . The solder station  20  also includes a barrel  40  aligned within hole  38  and includes an upper tinned layer  42  extending between and connecting the upper region of the barrel  40  and the heretofore previously exposed portion of the foil member  28   b . The upper surface  54  of the tinned layer  42  is located at a level beneath that of the upper surface  34  of the raised plastic mask portion  26   b  to partially form a horizontally aligned space  55  adjoining the upper region of a vertically aligned passage  56 , as also shown in FIGS. 3 and 4. 
     A connecting foil member  44  on the lower surface of the substrate  12  leads to the lower region of the solder station  20  and is covered by a lower plastic mask  46 . One end of the connecting foil member  44  is devoid of any plastic mask material  46  and extends about the lower region of and about the hole  38  and includes a lower tinned layer  48 . The lower tinned layer  48  extends as shown to bridge and connect the foil member  44  to the lower region of the barrel  40 . Terminal spacer pad  22  and the solder station  24  are constructed in a manner consistent with that of the terminal spacer pad  18  and solder station  20 , respectively, and are not described for purposes of brevity. 
     FIG. 3 illustrates the cross section view of the circuit board having improved soldering characteristics  10  of FIG. 2, including an electrical or electronic component represented by an LED  50  soldered into the soldering stations  20  and  24 . The bottom-surface  52  of the LED  50  is supported by the terminal spacer pads  18  and  22  and by the stand alone spacer pads  14  and  16  (FIG. 1) to space the bottom surface  52  of the LED  50  from the general level of the upper plastic mask  26  and to space the bottom surface  52  of the LED  50  from the upper regions of the solder stations  20  and  24 . Space  55 , which vents to atmosphere, is located at the upper region of the solder station  20  just above the upper tinned layer  42  and adjoining and in common with the upper portion of the passage  56 . The passage  56 , which can be annular and which extends upwardly for the release of soldering process gases and which connects with the space  55 , is maintained as a passage between the lead  58  of the LED  50  and the barrel  40 , as shown. Solder  60  as applied by known wave soldering processes connects the lower tinned layer  48  of the lower foil member  44  to the lead  58  of the LED  50 . 
     MODE OF OPERATION 
     FIG. 4 illustrates a close cross sectional view of FIG. 3 along line  4 — 4  of FIG.  3 . Solder  60  is applied by wave soldering techniques to flow liquidized solder into solder stations such as solder station  20 . Gases  62  given off by the soldering process rise vertically and unimpeded through the passage  56  and then travel horizontally and unimpeded along the space  55  which connects to the passage  56  and thence along the bottom surface  52  of the LED  50  and then outwardly to atmosphere, as shown in the illustration. Such paths of gaseous flow are shown by arrows  64   a - 64   n  in FIG. 1 where the gaseous flow rises vertically and then horizontally through and about and along the solder stations  20  and  24  and beneath the spaced electronic component (not shown) and thence to atmosphere. 
     FIG. 5, an alternate embodiment, illustrates a cross section view of a circuit board having improved soldering characteristics  10   a , including much of the structure of the previously described embodiment, having modified solder stations  20   a  and  24   a  which do not include a barrel  40  or an upper tinned layer  42  connecting the barrel  40  to the foil member  28   b . Hole  38  may be resized downwardly and the foil members  28   b  and  44  extended as required to juxtapose the upper region of a resized hole  38   a . A horizontally aligned space  55   a  surrounding the upper region of the hole  38   a  aligns and connects to the passage  56   a  which can be annular and which extends upwardly for the release of soldering process gases, as previously described. The circuit board having improved soldering characteristics  10   a  functions much the same as the previously described circuit board having improved soldering characteristics  10  but is of fewer components and thus more economical to produce. 
     Various modifications can be made to the present invention without departing from the apparent scope hereof. 
     CIRCUIT BOARD HAVING IMPROVED SOLDERING CHARACTERISTICS 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10 
                 circuit board having improved soldering characteristics 
               
               
                   
                 10a 
                 circuit board having improved soldering characteristics 
               
               
                   
                 12 
                 substrate 
               
               
                   
                 14 
                 stand alone spacer pad 
               
               
                   
                 16 
                 stand alone spacer pad 
               
               
                   
                 18 
                 terminal spacer pad 
               
               
                   
                 20 
                 solder station 
               
               
                   
                 20a 
                 solder station 
               
               
                   
                 22 
                 terminal spacer pad 
               
               
                   
                 24 
                 solder station 
               
               
                   
                 24a 
                 solder station 
               
               
                   
                 26 
                 upper plastic mask 
               
               
                   
                 26a-b 
                 raised plastic mask portions 
               
               
                   
                 28a-b 
                 foil members 
               
               
                   
                 30 
                 upper surface 
               
               
                   
                 34 
                 upper surface 
               
               
                   
                 38 
                 hole 
               
               
                   
                 38a 
                 hole 
               
               
                   
                 40 
                 barrel 
               
               
                   
                 42 
                 upper tinned layer 
               
               
                   
                 44 
                 foil member 
               
               
                   
                 46 
                 lower plastic mask 
               
               
                   
                 48 
                 lower tinned layer 
               
               
                   
                 50 
                 LED 
               
               
                   
                 52 
                 bottom surface 
               
               
                   
                 54 
                 upper surface 
               
               
                   
                 55 
                 space 
               
               
                   
                 55a 
                 space 
               
               
                   
                 56 
                 passage 
               
               
                   
                 56a 
                 passage 
               
               
                   
                 58 
                 lead 
               
               
                   
                 60 
                 solder 
               
               
                   
                 62 
                 gases 
               
               
                   
                 64a-n 
                 arrows