Abstract:
A process for manufacturing a multi-layer printed wire board, also referred to as a multilayer, comprising at least two electrically insulating substrates with electrically conductive traces or layers provided on at least three surfaces thereof, in which process, by means of lamination under pressure, a cured basic substrate based on a UD-reinforced synthetic material, provided on either side with traces, is combined with and bonded to a back-up substrate, wherein during the laminating process the back-up substrate is added to the basic substrate, the back-up substrate comprising a UD-reinforced cured core layer provided at least on the side facing the conducting traces of the basic substrate with a still plastically deformable (flowable) adhesive layer, and such a pressure is exerted on the laminate as to bring said cured core layer of the back-up substrate into contact or practically into contact with the conducting traces of the basic substrate, and the space between these traces is filled with the adhesive material, so bonding the basic substrate and the back-up substrate.
Abstract:
A warp-free laminate is produced by winding a first set of strands or filaments about a flat mandrel with a second set of strands being wound transverse to the first set. The two sets may be perpendicular to each other. The filaments are maintained under a controlled tension while being impregnated with a resin and during subsequent cure of the resin. In order to permit the formation of a warp-free product, the winding pattern is such that it forms a mirror image about a neutral axis or plane of symmetry. The winding pattern may be chosen to provide interstices in a predetermined pattern determining punching out or high speed drilling of hole openings for subsequent printed circuit applications.
Abstract:
A circuit board having multiple layers of a dielectric material, multiple layers of a conductive metal and multiple layers of graphite bonded together to form a composite multilayer printed circuit board having a desired coefficient of expansion and having strip and microstrip transmission lines for electrically connecting very high frequency electronic components mounted on the circuit board. The multiple layers of graphite are positioned in a symmetrical manner with respect to the thickness of the circuit board and selected in number to provide the circuit board with a desired coefficient of expansion. In addition, at least some of the layers of graphite are positioned in close proximity to some of the layers of conductive metal to provide enhanced thermal conduction from the mounted components.
Abstract:
Prepregs (124), laminates (120, 122), printed wiring board structures and processes for constructing materials and printed wiring boards that enable the construction of printed wiring boards with improved thermal properties. In one embodiment, the prepregs include substrates impregnated with electrically and thermally conductive resins (132). In other embodiments, the prepregs have substrate materials that include carbon. In other embodiments, the prepregs include substrates impregnated with thermally conductive resins. In other embodiments, the printed wiring board structures include electrically and thermally conductive laminates that can act as ground and/or power planes.
Abstract:
The present invention provides a method of forming unidirectional laminate prepreg, comprising the steps of: providing a support table; advancing a plurality of strands oriented generally parallel to each other along at least a portion of the table; positioning a removable carrier material between the strands and the table to support and move with the strands along at least a portion of the table; coating at least a portion of the strands with a resin matrix material to form a pre-cured prepreg; establishing a uniform thickness for the pre-cured prepreg; at least partially curing the matrix material of the pre-cured prepeg to form an at least partially cured prepreg; and accumulating the at least partially cured prepreg. In one nonlimiting embodiment of the invention, the strands comprise a plurality of glass fibers, the carrier material is plastic, the removing step includes the step of positioning an edge of a doctor blade in contact with an upper surface of the pre-cured prepreg to establish the thickness of the pre-cure prepreg, and the at least partially curing step includes the step of passing the pre-cured prepreg through at least one curing and drying oven.
Abstract:
A rigid flex printed circuit board wherein the flex section of said board comprises a basestock composite with edges, formed by laminating a conductive layer (56) to a flexible insulator layer (60), the conductor layer containing at least one conductive pathway (50) and the flexible insulator layer comprises fibers (48) dispersed in a matrix polymer. The fibers are oriented with respect to the conductive pathway so that the conductive pathway is substantially non-aligned with said fibers, substantially along an entirety of the conductive pathway in the flex section, so as to be flexible.
Abstract:
A description is provided of laminates for printed circuits using unidirectinal glass fabric produced with continuous yarn which is twisted, has a low number of twists or zero twisting turns with different gramme weights, interlaced warpwise with a leno interwoven binding using glass yarns of 5.5 to 22 Tex at a spacing of up to 20 cm. The application of these laminates to the manufacture of printed circuits offers advantages in terms of surface roughness and waviness, dimensional stability, evenness and perforability.
Abstract:
The present invention relates to a unidirectional glass fabric produced with continuous yarn (2, 3) which is twisted, plied or has zero twisting turns, with different gram weights and interlaced with thin glass yarns (3) as a stabilizing binding, use thereof in the manufacture of printed circuits and in numerous other industrial applications, and a method for the manufacture thereof.
Abstract:
The invention relates to a method of making a composite laminate comprising the steps of providing unidirectionally oriented parallel fibres (UD filaments) (3) with a resin matrix to form a composite UD layer and laminating a plurality of UD layers to form a UD crossply laminate (18). In the method of the invention, the UD filaments are impregnated with a melt of a resin which in the uncured form solidifies below a certain temperature (Tm). Thereupon the UD filaments-containing resin is cooled to a temperature below Tm to produce said composite UD layer. The produced composite UD layer is irreversibly cured before or after lamination. Notably latent curing resins are suitable. The impregnation is preferably conducted by coating a process belt (8) with solid resin (6), laying the UD filaments onto the resin, and heating the resin so as to form the resin melt. The heating of the resin is preferably conducted by means of IR irradiation (11).