Patents by Inventor Tung F. Yeh

Tung F. Yeh 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).

  • Heat and radiation-sensitive imaging medium, and processes for use thereof
    Patent number: 6258505
    Abstract: An imaging medium comprises a substrate carrying a color-change layer. This color-change layer comprises two layers or phases comprising two color-forming reagents which react upon heating to cause a change in the color of the layer. The color-change layer is deactivated by exposure to actinic radiation such that after deactivation it no longer undergoes its thermal color-change. The color-change layer is detachable from the substrate by heating to a temperature lower than required to cause the color change, so that upon contact of the imaging medium with a receiving sheet each individual pixel of the color-change layer may be left attached to the substrate, transferred to the receiving sheet but left uncolored, or transferred to the receiving sheet and colored to a color level determined by the energy used in the associated thermal print head element.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: July 10, 2001
    Assignee: Polaroid Corporation
    Inventors: Jayprakash C. Bhatt, Daoshen Bi, F. Richard Cottrell, Rong C. Liang, William C. Schwarzel, Tung F. Yeh
  • Heat and radiation-sensitive imaging medium, and processes for use thereof
    Patent number: 6054246
    Abstract: An imaging medium comprises a substrate carrying a color-change layer. This color-change layer comprises two layers or phases comprising two color-forming reagents which react upon heating to cause a change in the color of the layer. The color-change layer is deactivated by exposure to actinic radiation such that after deactivation it no longer undergoes its thermal color-change. The color-change layer is detachable from the substrate by heating to a temperature lower than required to cause the color change, so that upon contact of the imaging medium with a receiving sheet each individual pixel of the color-change layer may be left attached to the substrate, transferred to the receiving sheet but left uncolored, or transferred to the receiving sheet and colored to a color level determined by the energy used in the associated thermal print head element.
    Type: Grant
    Filed: July 1, 1998
    Date of Patent: April 25, 2000
    Assignee: Polaroid Corporation
    Inventors: Jayprakash C. Bhatt, Daoshen Bi, F. Richard Cottrell, Rong C. Liang, William C. Schwarzel, Tung F. Yeh