Patents Assigned to Sigma Technologies International, Inc.
  • Patent number: 6649433
    Abstract: A heterogeneous blend of small electron-donor organic molecules and polymerizable monomers is flash evaporated to provide a molecular-level vapor-phase mixture, which is then condensed and cured in-line as a homogeneous liquid layer on a flexible web containing an anodic layer. The procedure is repeated with an electron-acceptor organic substance, which is deposited over the electron-donor layer. A metallic cathode is then deposited over the electron-acceptor layer and the composite OLED product is packaged. The electrical characteristics and the thickness of the metallic cathode and the composition of the polymer layers are selected such as to produce the gasification of elemental carbon generated by dielectric breakdowns and the oxidation of any exposed cathodic surface, thereby providing a built-in mechanism to prevent the propagation of the damage caused by electrical shorts.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: November 18, 2003
    Assignee: Sigma Technologies International, Inc.
    Inventors: Michael G. Mikhael, Angelo Yializis
  • Patent number: 6468595
    Abstract: A thermally-stable cationic photoinitiator capable of flash vaporization under vacuum and temperature conditions of an available flash-evaporation chamber is selected. The photoinitiator is mixed with a cation-polymerizable monomer and/or oligomer of interest and the mixture is flash evaporated and condensed in conventional manner as a film on a cold substrate. The resulting vacuum-deposited, homogeneous layer is cured with a high-energy radiation source that causes the cationic photoinitiator to liberate acidic species that catalyze the crosslinking of the monomer/oligomer compounds in its deposited film form. As a result of the homogeneous, pinhole-free nature of the vacuum deposition process, the thin-film polymer product does not suffer from the disadvantages attendant to prior-art atmospheric processes for cationically-cured polymers.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: October 22, 2002
    Assignee: Sigma Technologies International, Inc.
    Inventors: Michael G. Mikhael, Angelo Yializis
  • Patent number: 6447553
    Abstract: A radiation curable monomer and a dystuff are mixed in a curable formulation and fed into a hot evaporator under vacuum. The blend is flash evaporated through a nozzle and recondensed onto a moving substrate in contact with a temperature-controlled rotating drum. The condensed film is then crosslinked with a high-energy ultraviolet or electron-beam radiation source to effect cross-linking of the monomer. The resulting product consists of a crosslinked polymer matrix incorporating dyestuff molecules within its structure, which dramatically enhances the durability, solvent resistance, heat stability and migration fastness of the product. These properties can be further improved by chemically bonding the dyestuff molecules with the crosslinked polymer network, which can be accomplished by judiciously functionalizing the dyestuff with appropriate functional groups designed to polymerize or to react with the curable monomer.
    Type: Grant
    Filed: October 24, 2000
    Date of Patent: September 10, 2002
    Assignee: Sigma Technologies International, Inc.
    Inventors: Michael G. Mikhael, Angelo Yializis
  • Patent number: 6441553
    Abstract: A porous metallic layer is incorporated in one of the electrodes of a plasma treatment system. A plasma gas is injected into the electrode at substantially atmospheric pressure and allowed to diffuse through the porous layer, thereby forming a uniform glow-discharge plasma. The film material to be treated is exposed to the plasma created between this electrode and a second electrode covered by a dielectric layer. Because of the micron size of the pores of the porous metal, each pore also produces a hollow cathode effect that facilitates the ionization of the plasma gas. As a result, a steady-state glow-discharge plasma is produced at atmospheric pressure and at power frequencies as low as 60 Hz. According to another aspect of the invention, vapor deposition is carried out in combination with plasma treatment by vaporizing a substance of interest, mixing it with the plasma gas, and diffusing the mixture through the porous electrode.
    Type: Grant
    Filed: September 12, 2000
    Date of Patent: August 27, 2002
    Assignee: Sigma Technologies International, Inc.
    Inventors: Angelo Yializis, Wolfgang Decker, Michael G. Mikhael, Shahid A. Pirzada
  • Patent number: 6270841
    Abstract: A monomer is selected to produce a polymeric film having desirable characteristics for a particular application. The monomer is polymerized under controlled conditions to produce a solid oligomer having those characteristics at a molecular weight suitable for evaporation under vacuum at a temperature lower than its thermal decomposition temperature. The process of polymerization to produce the oligomer is carried out under conditions that yield a finite molecular-chain length with no residual reactive groups. The solid oligomer so produced is liquefied and extruded as a film onto a revolving drum in the evaporation section of a conventional vapor deposition chamber, and it is then cryocondensed on a cold substrate to form a solid thin film having the same desirable characteristic selected in the solid oligomer constituting the starting material.
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: August 7, 2001
    Assignee: Sigma Technologies International, Inc.
    Inventors: Michael G. Mikhael, Angelo Yializis
  • Patent number: 6118218
    Abstract: A plasma treater incorporates a porous metallic layer in one of the electrodes. The porous layer is selected with pores of average size within one order of magnitude of the mean free path of the plasma gas at atmospheric pressure. The plasma gas is injected into the electrode at substantially atmospheric pressure and allowed to diffuse through the porous layer, thereby forming a uniform glow-discharge plasma. The film material to be treated is exposed to the plasma created between this electrode and a second electrode covered by a dielectric layer. Because of the micron size of the pores of the porous metal, each pore also produces a hollow cathode effect that facilitates the ionization of the plasma gas. As a result, a steady-state glow-discharge plasma is produced at atmospheric pressure and at power frequencies as low as 60 Hz.
    Type: Grant
    Filed: February 1, 1999
    Date of Patent: September 12, 2000
    Assignee: Sigma Technologies International, Inc.
    Inventors: Angelo Yializis, Shahid A. Pirzada, Wolfgang Decker