Sealing Layer Oxygen Gradient for Organic EL Adhesion
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Solution Overview
Problem
The adhesiveness between inorganic material films and resin material layers in organic EL display devices is low, leading to a decrease in mechanical strength.
Innovation Solution
A sealing layer structure comprising a first inorganic material film, a second inorganic material film with higher oxygen content, a resin material layer, and a third inorganic material film is used, where the second inorganic material film is in contact with the resin material layer, enhancing the adhesiveness and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing layer is formed using a combination of inorganic material film and resin material layer, then the light emitting element is protected from moisture, but the adhesiveness between the inorganic material film and resin material layer is low, leading to decreased mechanical strength
Solution Approach 1:
A third inorganic material film with intermediate oxygen content is introduced between the first inorganic material film (lower oxygen content) and the resin material layer. This intermediate film serves as a mediator that improves the adhesiveness between the inorganic material film and the resin material layer, thereby enhancing the mechanical strength of the sealing layer while maintaining the moisture protection function.
Solution Approach 2:
The oxygen content of the inorganic material films is systematically varied to optimize adhesion. The first inorganic material film has a lower oxygen content, the third inorganic material film has an intermediate oxygen content, and the second inorganic material film has a higher oxygen content. This parameter change in oxygen content creates a gradient structure that improves interfacial adhesion between different materials in the sealing layer.
2Reliability
If a sealing layer is formed using a combination of inorganic material film and resin material layer, then the light emitting element is protected from moisture, but the adhesiveness between the inorganic material film and resin material layer is low
Solution Approach 1:
The third inorganic material film acts as an intermediary layer between the first inorganic material film and the resin material layer. This intermediate film with intermediate oxygen content facilitates better bonding between the inorganic material film and the resin material layer, eliminating the harmful effect of low adhesiveness while preserving the moisture barrier function.
Solution Approach 2:
The sealing layer is designed as a composite structure comprising multiple inorganic material films with different oxygen contents and a resin material layer. This composite structure leverages the complementary properties of different materials to achieve both effective moisture protection and high adhesiveness, resolving the contradiction between these two requirements.
Data Source
AI summary
A display device according to an embodiment of the present invention includes: a substrate having a display region for displaying an image; a plurality of pixels located in the display region of the substrate; and a sealing layer covering the plurality of pixels, wherein the sealing layer includes a first inorganic material film, a second inorganic material film, a resin material layer, and a third inorganic material film in this order from the side where the pixels are arranged, and the second inorganic material film is in contact with the resin material layer, has a composition different from that of the first inorganic material film, and has a higher oxygen content than the first inorganic material film.