Patents by Inventor Karuppiah Chandrasekaran

Karuppiah Chandrasekaran has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Ink jet heads having photoresist layer containing poly (amic acid)
    Patent number: 6364465
    Abstract: The durability of ink jet print heads is improved when the intermediate photoresist layer contains a poly(amic acid) prepared from at least one dianhydride and at least one aliphatic diamine.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: April 2, 2002
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: Karuppiah Chandrasekaran
  • Ink jet print head photoresist layer having durable adhesion characteristics
    Patent number: 5557308
    Abstract: The ink jet print head has a sandwich structure of a top plate, a bottom plate, and a dry film photoresist intermediate layer that defines liquid pathways and discharge orifices. The photoresist layer contains a phosphorus compound having substituted or unsubstituted alkyl or aryl groups having 6 to 10 carbons. The ink jet print head photoresist layers containing these phosphorus compounds exhibit durable bonds to the top and bottom plates of the print head and excellent ink resistance.
    Type: Grant
    Filed: July 8, 1994
    Date of Patent: September 17, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Karuppiah Chandrasekaran
  • Aqueous processable, multilayer, photoimageable permanent coatings for printed circuits
    Patent number: 5405731
    Abstract: The use of a two layer photoimageable, aqueous processable, resist with a hydrophic binder in the outermost layer provides a permanent coating highly resistant to printed circuit processing chemicals. This resistance results in levels of adsorbed or absorbed ionic contamination less than 14 micrograms per square inch.
    Type: Grant
    Filed: December 22, 1992
    Date of Patent: April 11, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Karuppiah Chandrasekaran, Mark R. McKeever, James W. O'Neil
  • Aqueous processable, multilayer, photoimageable permanent coatings for printed circuits
    Patent number: 5288589
    Abstract: The use of a two layer photoimageable, aqueous processable, resist with an amphoteric binder in the layer laminated directly to a printed circuit board provides a permanent coating with improved adhesion throughout the lamination process while maintaining other desirable properties such as storage stability and circuit encapsulation.
    Type: Grant
    Filed: December 3, 1992
    Date of Patent: February 22, 1994
    Inventors: Mark R. McKeever, Karuppiah Chandrasekaran