The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 15, 1979
Filed:
Dec. 19, 1977
Ifay Chang, Mahopac, NY (US);
International Business Machines Corporation, Armonk, NY (US);
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. The principle of this disclosure may be generalized to three or more layers so that greater flexibility of color choice is obtainable.