Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-07-27
2004-03-16
Edmondson, L. (Department: 1725)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S767000, C361S770000, C174S261000, C439S038000, C228S175000
Reexamination Certificate
active
06707683
ABSTRACT:
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.
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Bravek Eric S.
Uehran Randy S.
Daktronics, Inc.
Edmondson L.
Jaeger Hugh D.
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