Forming a thin-film EL element
AssigneeKomatsu Ltd.
InventorsTakashi Nire, Atsushi Miyakoshi
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Abstract
A thin-film EL element which does not permit the color of the emitted light to change irrespective of a change in the voltage, which remains chemically stable and which emits light of high brightness even on a low voltage. The element comprises two or more polycrystalline thin light emitting layers (4, 5, 6) and one or more thin insulating layers (3, 7). The interface between a thin film and a thin film constituting a light emitting layer is formed by epitaxial growth, and the electrical characteristics of the element are equivalent to those of a single circuit which includes two Zener diodes (12, 13) connected in series, a capacitor (14) connected in parallel with the serially connected Zener diodes, and a capacitor (15) connected to one end of the capacitor (14).
Claims13
A process for forming a thin-film EL element which comprises:
- forming a first electrode layer on a substrate,
- forming a first insulator layer on said first electrode layer, thereby forming an initial laminate,
- utilizing one of a Multi-Source Deposition Method and a Chemical Vapor Deposition Method to expose a surface of said first insulator layer of said initial laminate in a vacuum chamber to vapors of chemical elements to be chemically bonded to said surface of said first insulator layer to form a first polycrystalline light emitting layer, and
- utilizing one of a Multi-Source Deposition Method and a Chemical Vapor Deposition Method to supply onto a surface of said first light emitting layer, while said surface of said first light emitting layer is exposed in a vacuum chamber, vapors of chemical elements to be chemically bonded to said surface of said first light emitting layer to form a second polycrystalline light emitting layer by epitaxial growth on said surface of said first light emitting layer,
- wherein each of said first and second polycrystalline light emitting layers comprises a base material and is capable of emitting light, with the base material of said first polycrystalline light emitting layer being different from the base material of said second polycrystalline light emitting layer and with the color of light emitted by said first polycrystalline light emitting layer being different from the color of light emitted by said second polycrystalline light emitting layer;
- wherein the step of supplying vapors of chemical elements onto a surface of said first insulator layer comprises supplying vapors of Zn and S, and wherein the step of supplying vapors of chemical elements onto a surface of said first polycrystalline light emitting layer comprises supplying vapors of Ba, Sr, and S.
Dependencies are inferred from the claim text.