Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Patent
1990-01-11
1992-03-24
Nimmo, Morris H.
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
29846, 106 20, 118411, 118412, 118415, 264 407, 264104, 264254, 425114, 4251331, 425145, 425150, H05K 100, B28B 722, B23B 1900
Patent
active
050990900
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention pertains to the production of circuit boards; in particular the apparatus, methods, and materials for forming conductive circuitry between points on such boards by extrusion; and boards produced by such apparatus.
BACKGROUND OF THE INVENTION
For at least the past twenty-five years, there has been in the U.S. and around the world a rapidly growing electronics industry in which an integral and important part has been the development and manufacture of printed circuit boards. These printed circuit boards are typically formed of electrically conductive traces supported by nonconductive substrates (i.e. boards) in such a manner that electrical and electronic components, for example resistors, capacitors, integrated circuits, and transistors, may be mounted so that the result is an electrical circuit incorporating these components. The electrically conductive traces are the "wires" of the circuit, and the board provides structural integrity, facility for mounting to chassis frames, and support for interconnection to other circuitry. Printed circuit boards are an integral part of almost every electronic product and are often the most complicated and expensive parts of the entire device. All of the working parts and electronic memory of many computers, for example, are implemented on one or more printed circuit boards.
The desktop computer is a good example of a product that makes extensive use of printed circuit boards. The development of integrated circuits has been instrumental in the development of desktop computers, which are based on powerful central processing units (CPUs) and memory chips capable of storing large amounts of digital information. The motivation for more and more processing power, such as sophisticated graphics generation and display, has led to miniaturization techniques to put more and more devices on a single integrated circuit chip. By the same motivation, larger numbers of memory chips and processors have been brought into action in limited space environments, such as the chassis of a desktop computer, by innovative techniques for increasing the density of printed circuits.
Just as in the development of any product, certain techniques have emerged over the years for producing printed circuit boards that have proven to be useful and effective, and have come to be used by many manufacturers. According to one such process, as described in the Handbook of Printed Circuit Manufacturing, by Raymond N. Clark, published in 1985 by Van Nostrand, a typical printed circuit board begins with a sheet of nonconductive polymer material, such as fiberglass reinforced epoxy. The material that will eventually form the traces is copper foil, and a thin sheet of the foil is mounted to one or both sides of the fiberglass sheet, typically with epoxy resin as an adhesive to form a blank. Holes are usually drilled into the laminated blank. Some holes are for such purposes as registration, alignment and mounting of the board to other elements of an assembly, many are for accepting wire leads of electrical components to be finally mounted to the finished board, and many are to provide for electrical contact through the laminate between the eventual traces on one side and the traces on the other.
After holes are drilled, electroless plating operations are used in those cases where needed to plate conductive metal, usually copper, through the holes. Imaging techniques are subsequently used to lay a pattern over the copper foil defining the circuit traces to be formed. The two commonly used techniques are silk screening and dry film photoresist. In each of these, the pattern, called artwork, has to be separately determined and rendered in masks as part of the process. In the silkscreening process, plating resist material is applied to the foil through openings in the mask. In the dry film photoresist process the entire copper foil area is coated, then a pattern is cured through a mask by radiation, such as ultraviolet light. The uncured resist is then washed away. In
REFERENCES:
patent: Re30274 (1980-05-01), Bolon et al.
patent: 3240624 (1966-03-01), Beck
patent: 3892339 (1975-07-01), Idler
patent: 4075301 (1978-02-01), Oswald
patent: 4094852 (1978-06-01), Sundermann et al.
patent: 4187339 (1980-02-01), Cayrol
patent: 4237606 (1980-12-01), Niwa et al.
patent: 4291642 (1981-09-01), Kolc
patent: 4402135 (1983-09-01), Schweingruber et al.
patent: 4557860 (1985-12-01), DiSalvo et al.
patent: 4564410 (1986-01-01), Clitheros et al.
patent: 4568592 (1986-02-01), Kawaguchi et al.
patent: 4652398 (1987-03-01), Goswami et al.
patent: 4694138 (1987-09-01), Oodaira
patent: 4696764 (1987-09-01), Yamazaki
patent: 4720914 (1988-01-01), Maeda et al.
patent: 4743465 (1988-05-01), Saeki et al.
patent: 4748068 (1988-05-01), Fahner et al.
patent: 4749347 (1988-06-01), Valavaara
patent: 4755123 (1988-07-01), Otake
patent: 4775573 (1988-10-01), Turek
patent: 4818437 (1989-04-01), Wiley
patent: 4842504 (1989-06-01), Bentivoglio et al.
patent: 4872417 (1989-10-01), Kuwabara et al.
patent: 4874548 (1989-10-01), Hajovsky
patent: 4911629 (1990-03-01), Fujita
patent: 4913638 (1990-04-01), Buja
patent: 4946356 (1990-08-01), Kumazaki
patent: 4952364 (1990-08-01), Matsuda et al.
patent: 4961965 (1990-10-01), Dietz
Delio, R., Extrusion Printing, IBM Technical Disclosure Bulletin, vol. 15, No. 10, Mar. 1973, pp. 3029 and 3030.
Allan G. Graham
Bates Kenneth N.
DeBardi Gary A.
Erley Robert B.
Hamade Ramzi F.
Ariel Electronics, Inc.
Nimmo Morris H.
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