Patents by Inventor Ifay Chang

Ifay Chang 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: 4155030
    Abstract: The disclosure utilizes a memory electroluminescent (EL) layer which has brightness-voltage (B-V) characteristics with multistable hysteresis loops of one color emission. Another EL layer of second color emission is incorporated therewith for a multicolor display device. The device comprises the two EL layers fabricated in sandwich form separated from each and from the electrodes by insulating layers which are inserted for breakdown protection and isolation of the two EL layers. Certain insulating layers may be omitted if the two EL layers are made of compatible materials and the hysteresis characteristics are not effected. In steady operation, an AC voltage signal is applied to the sandwiched device to maintain a display characteristic. A superposed switching voltage or electron beam or light beam is used to trigger a desired display. The displayed image may be erased by reducing sustaining AC voltage below threshold value.
    Type: Grant
    Filed: December 19, 1977
    Date of Patent: May 15, 1979
    Assignee: International Business Machines Corporation
    Inventor: Ifay Chang