1. Field of the Invention
The present invention relates to a method for manufacturing an electroluminescence display. More specifically, it relates to a method for manufacturing an electroluminescence display apparatus wherein a substrate onto which an electroluminescence element is formed is sealed using a sealing substrate.
2. Description of the Related Art
In recent years, display apparatuses employing electroluminescence (EL: Electroluminescence) elements have received widespread attention.
A typical EL element is configured by sequentially laminating, for example, an anode comprising a transparent electrode such as ITO (Indium Tin Oxide), a hole transporting layer, an emissive layer and a cathode on a transparent substrate. In such an EL element, holes injected from the anode and electrons injected from the cathode are recombined in the emissive layer so that organic molecules contained therein are excited and then excitons are generated. Subsequently, the emissive layer emits light in the deactivation process of the excitons and the light is emitted from the transparent anode to the outside through the transparent substrate.
A typical display apparatus using an EL element as described above has a sealing substrate to seal the transparent element substrate onto which the EL element is formed in order to prevent degradation of the characteristics of the EL element due to moisture in the EL element. More specifically, in such display apparatus, degradation in characteristics of the EL element due to moisture in the EL element is avoided by bonding an element surface of the transparent element substrate having the above-described element formed thereon with the sealing substrate made of, for example, metal. When these substrates are bonded, a sealing resin, for example, a resin in which are mixed bead-shaped glass fibers to create a spacer, is used to define a gap between the sealing substrate and the transparent element substrate onto which the EL element is formed. However, because the heat resistance of typical EL element materials is low, it is not possible to ensure that quality of an EL display apparatus will be maintained when a sealing resin requiring a high-temperature heat treatment is used to bond the transparent element substrate with the sealing substrate.
In order to resolve this problem, it can be conceived to adopt a method for applying a sealing resin cured with ultraviolet light between the transparent element substrate and the sealing substrate, and the sealing resin is irradiated with the ultraviolet light transmitted through the sealing substrate to bond the transparent element substrate and the sealing substrate. The use of the sealing resin cured with ultraviolet light or the like allows the transparent element substrate to be bonded with the sealing substrate without exposing the EL element to elevated temperatures. Accordingly, it becomes possible to maintain adequate quality for an EL display apparatus.
Here it should be noted that because the sealing resin is irradiated with light emitted from a UV lamp on the transparent element substrate side of the device, not just the sealing resin, but also the EL element and other components are exposed to the ultraviolet light during the curing process. Therefore, although degradation in EL element characteristics resulting from exposure to elevated temperatures can be prevented, there remains a possibility that characteristics can be degraded due to short-time exposure to the ultraviolet irradiation.