DAVID DURAND
Water and Wastewater in Providence, RI

5180513, Jan 19, 1993

Jan 30, 1990

7/472634

David Durand - Providence RI

Key-Tech, Inc. - Cranston RI

B32B 300

252 6255

A shielded plastic enclosure for housing electronic equipment is provided, on at least one interior surface thereof, with a layer of shielding composition which is a suspension of silver-coated magnetite particles in a U. V. cured cycloaliphatic epoxy resin. The layer of this shielding composition has a thickness sufficient to effectively shield against electromagnetic interference, radio frequency interference and electrostatic discharge.

5183593, Feb 2, 1993

Jun 4, 1990

7/533682

David Durand - Providence RI
David P. Vieau - East Greenwich RI
Tai S. Wei - Warwick RI

Poly-Flex Circuits, Inc. - Cranston RI

H01B 102

252514

An electrically conductive cement which when used to bond electrically conductive mating surfaces provides substantially stable conductivity characteristics under high humidity conditions; comprised of a carrier that provides a volumetric shrinkage of more than about 6. 8% (vol. ) and a conductive filler including agglomerates, particles, powders, flakes, coated nickel particles, and coated glass spheres, having size and surface characteristics that maintain stable electrical contact by forming a moisture resistant contact with an electrical component lead. The carrier having a volumetric shrinkage between the uncured and cured states of greater than about 6. 8% (vol) appears to effect a compaction of the filler particles causing the particles to be forced into enhanced electrical contact with the surfaces to be connected and to provide a measure of compaction between the particles themselves to enhance particle-to-particle conduction. The shrinkage of the polymeric carrier during curing places the interior particles under compression with sufficient force to urge the particles into engagement with one another as well as to cause the particles to penetrate non-conductive oxides that may be present on a component lead.

5180523, Jan 19, 1993

Nov 14, 1989

7/436199

David Durand - Providence RI
David P. Vieau - East Greenwich RI

Poly-Flex Circuits, Inc. - Cranston RI

H01B 122

252512

An electrically conductive cement having substantially stable conductivity and resistance characteristics under high humidity conditions comprises a mixture of two epoxy resins with the proportion of each epoxy resin adjusted to provide a volumetric shrinkage in the mixture in the 4 to 16% and a conductive silver particular filler including agglomerates having size and surface characteristics that maintain stable electrical contact with an electrical component lead. The epoxy mixture is preferably a combination of a high-shrinkage epoxy resin and a lower-shrinkage epoxy resin in the appropriate amounts of each so as to produce the desired volumetric shrinkage characteristic. The conductive particle filler is preferably an admixture of silver flakes, silver powder, and an effective amount of silver agglomerates. The agglomerates are irregularly shaped particles having multiple surface indentations and recesses to produce many rough-edged salients or ridges and having a particle length, width, and thickness aspect ratio of about 1:1:1. An effective amount of such agglomerates appears to effect penetration of surface oxides when establishing the cemented connection as a result of the volumetric shrinkage of the polymeric carrier upon curing.

5326636, Jul 5, 1994

Sep 29, 1992

7/953609

David Durand - Providence RI
David P. Vieau - East Greenwich RI
Tai S. Wei - Warwick RI

Poly-Flex Circuits, Inc. - Cranston RI

B32B 900

428323

An electrically conductive cement having substantially stable conductivity and resistance characteristics under high humidity conditions comprises a mixture of two epoxy resins with the proportion of each epoxy resin adjusted to provide a volumetric shrinkage in the mixture in the 4 to 16% and a conductive silver particular filler including agglomerates having size and surface characteristics that maintain stable electrical contact with an electrical component lead. The epoxy mixture is preferably a combination of a high-shrinkage epoxy resin and a lower-shrinkage epoxy resin in the appropriate amounts of each so as to produce the desired volumetric shrinkage characteristic. The conductive particle filler is preferably an admixture of silver flakes, silver powder, and an effective amount of silver agglomerates. The agglomerates are irregularly shaped particles having multiple surface indentations and recesses to produce many rough-edged salients or ridges and having a particle length, width, and thickness aspect ratio of about 1:1:1. An effective amount of such agglomerates appears to effect penetration of surface oxides when establishing the cemented connection as a result of the volumetric shringage of the polymeric carrier upon curing.

4960614, Oct 2, 1990

Jun 14, 1989

7/365712

David Durand - Providence RI

Key-Tech, Inc. - Cranston RI

B05D 306

427 541

A method for producing a circuit board involves printing a U. V. curable ink onto a substrate in a desired circuit pattern and curing the ink by exposing it to a pulsed U. V. source having an output in the region between 360 nm and 420 nm in a pulsing manner consisting of 5 to 8 one-half second exposure periods where each exposure period is followed by a non-exposure period of about 2 to 3 seconds.

5531020, Jul 2, 1996

Aug 27, 1993

8/112225

David Durand - Providence RI
Roger A. Iannetta - Warwick RI

Poly Flex Circuits, Inc. - Cranston RI

H05K 334

29840

A method of making a planar, subsurface electronic circuit having at least one electronic circuit component assembled therewith is disclosed. First, three dimensional, essentially square channels interspersed with lands are formed within a dielectric material on a substrate. The channels are then filled in one pass with a curable polymeric material containing a conductive metal filler so that the upper surfaces of the circuit trace formed by this conductive material are at essentially the same level as the upper surface of the lands. Circuit components are place to engage the conductive material. The curable material is then cured after placing the electronic component(s).

5061551, Oct 29, 1991

Jan 30, 1990

7/472194

David Durand - Providence RI

Key-Tech, Inc. - Cranston RI

B32B 900

428209

A method for producing a circuit board involves printing a U. V. curable ink onto a substrate in a desired circuit pattern and curing the ink by exposing it to a pulsed U. V. source or subjecting the circuit pattern prepared from a U. V. curable ink containing magnetite particles to a magnetic field to move the magnetite particles to the upper surface of the U. V. curable ink. Other embodiments include circuit boards made in accordance with these methods and the use of the U. V. curable ink as a shielding composition for enclosures housing electronic equipment.

5006397, Apr 9, 1991

Jan 30, 1990

7/472310

David Durand - Providence RI

Key-Tech, Inc. - Cranston RI

B32B 900

428209

A method for producing a circuit board involves printing a U. V. curable ink onto a substrate in a desired cirucit pattern and curing the ink by exposing it to a pulsed U. V. source or subjecting the circuit pattern prepared from a U. V. curable ink containing magnetite particles to a magnetic field to move the magnetite particles to the upper surface of the U. V. curable ink. Other embodiments include circuit boards made in accordance with these methods and the use of the U. V. curable ink as a shielding composition for enclosures housing electronic equipment.

5455394, Oct 3, 1995

Aug 27, 1993

8/112226

David Durand - Providence RI
Chon M. Wong - Lincoln RI
Roger A. Iannetta - Warwick RI

Poly-Flex Circuits, Inc. - Cranston RI

H05K 118

174261

A polymer lead frame is made from a flexible substrate with flexible conductive traces. The generally square lead frame has diagonal cutouts partially extending from the corners towards the center, as well as a central hole that lies within a footprint of the die. The die is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive. The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterized by a non-planar, non-bump-like surface with concavities having depths of at least about one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.