Patents by Inventor Ramanujan Srinivasa

Ramanujan Srinivasa 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).

  • Patent number: 7294290
    Abstract: The invention relates to novel photochromic composition for controlling the transmission of light comprising an organic polymer, photochromic dye, photosensitizer and an electron acceptor. The invention also includes a method for preparing photochromic films.
    Type: Grant
    Filed: June 17, 2004
    Date of Patent: November 13, 2007
    Assignee: NGX, Inc.
    Inventor: Ramanujan Srinivasa
  • Publication number: 20060014880
    Abstract: The invention describes a novel polymer composite comprising nano-talc characterized by an isoelectric point of about 2.5 to about 3.5, a specific surface area greater than about 70 m2/g, and surface hydroxy groups with corresponding hydroxy equivalent weight of about 210 to about 560; and a polymer phase. Specific composites include polyurethane composites prepared from aqueous nano-talc slurries and aqueous dispersible isocyanate terminated polyurethane prepolymers. The invention further embodies a polyurethane composite composition that is a primer coat, base coat or clear top coat for automobiles and metal articles.
    Type: Application
    Filed: April 11, 2005
    Publication date: January 19, 2006
    Inventors: Qiping Zhong, Mei Li, Ramanujan Srinivasa, Jianhong He
  • Publication number: 20050026072
    Abstract: The invention relates to novel photochromic composition for controlling the transmission of light comprising an organic polymer, photochromic dye, photosensitizer and an electron acceptor. The invention also includes a method for preparing photochromic films.
    Type: Application
    Filed: June 17, 2004
    Publication date: February 3, 2005
    Inventor: Ramanujan Srinivasa
  • Patent number: 6193912
    Abstract: Electrochromic compounds capable of reversibly attenuating the transmittance of the near infrared portion of the electromagnetic spectrum are provided. These compounds exhibit an energy difference between the singly occupied molecular orbital (SOMO) energy and the highest doubly occupied molecular orbital (HDOMO) energy (ESOMO−EHDOMO) of less than about 3.6 eV. In addition, these compounds have a transition moment of the configuration made up of the HDOMO and SOMO that is “long axis polarized”.
    Type: Grant
    Filed: March 3, 1998
    Date of Patent: February 27, 2001
    Assignee: Gentex Corporation
    Inventors: Dave Thieste, Harlan J. Byker, Kelvin Baumann, Ramanujan Srinivasa
  • Patent number: 6037471
    Abstract: An improved electrochromic device, the device incorporating an electrochromic medium that comprises at least three electroactive materials having absorption spectra that add together such that the color of the electrochromic medium can be pre-selected by individually choosing the concentrations of the at least three electroactive materials. The electrochromic medium generally maintains the pre-selected perceived color throughout its normal range of voltages when used in an electrochromic device. The at least three electroactive materials include at least one electrochemically reducible material (cathodic material), at least one electrochemically oxidizable material (anodic material) and at least one additional electroactive material which may be either an anodic or cathodic material. Thus, there are always three electroactive materials present in the medium, with at least two either being anodic or cathodic materials.
    Type: Grant
    Filed: August 26, 1998
    Date of Patent: March 14, 2000
    Assignee: Gentex Corporation
    Inventors: Ramanujan Srinivasa, Darla J. French, Rongguang Lin, Thomas F. Guarr, Harlan J. Byker, Kelvin L. Baumann, David A. Theiste
  • Patent number: 5998617
    Abstract: An improved electrochromic device, the device incorporating an electrochromic medium that comprises at least three electroactive materials having absorption spectra that add together such that the color of the electrochromic medium can be pre-selected by individually choosing the concentrations of the at least three electroactive materials. The electrochromic medium generally maintains the pre-selected perceived color throughout its normal range of voltages when used in an electrochromic device. The at least three electroactive materials include at least one electrochemically reducible material (cathodic material), at least one electrochemically oxidizable material (anodic material) and at least one additional electroactive material which may be either an anodic or cathodic material. Thus, there are always three electroactive materials present in the medium, with at least two either being anodic or cathodic materials.
    Type: Grant
    Filed: April 2, 1997
    Date of Patent: December 7, 1999
    Assignee: Gentex Corporation
    Inventors: Ramanujan Srinivasa, Darla J. French, Rongguang Lin, Thomas F. Guarr, Harlan J. Byker, Kelvin L. Baumann, David A. Theiste
  • Patent number: 5770114
    Abstract: The present invention concerns compositions, which comprise an aprotic polar solvent, at least one electrochromic compound, and a compound of the formula I ##STR1## wherein R.sub.1 is, for example, tert-butyl, and R.sub.2 is, for example, --CH.sub.2 --CH.sub.2 --COO--R.sub.7 --, where R.sub.7 is n-butyl or n-pentyl. Among embodiments of the invention are compositions used as media of variable transmittance in electrochromic devices, especially single-compartment, self-erasing, solution-phase electrochromic devices. The compounds of Formula I have increased solubility in aprotic polar solvents used in electrochromic devices and are effective in stabilizing compositions, which comprise at least one electrochromic compound and are useful as media of variable transmittance in electrochromic devices, against degradation due to exposure to UV-radiation.
    Type: Grant
    Filed: August 6, 1997
    Date of Patent: June 23, 1998
    Assignee: Gentex Corporation
    Inventors: Harlan J. Byker, Ramanujan Srinivasa