Display Insulating Layer Depressed Portion for Film Adhesion
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Solution Overview
Problem
Display apparatuses face issues with adhesion between layers, leading to film separation and reduced yield and reliability, especially in high-resolution and high-definition applications.
Innovation Solution
A display apparatus design incorporating a first and second light-emitting element with specific insulating layers, where the second insulating layer has a depressed portion to alleviate stress and prevent film separation, and a method for manufacturing involving photolithography and etching treatments to form island-shaped light-emitting layers and functional layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If stress is applied to a layer included in a display apparatus, then the layer can be maintained in a flexible state, but the adhesion between films is decreased, leading to film separation
Solution Approach 1:
The second insulating layer is divided into a first region and a second region with different stress states. The depressed portion creates a clear segmentation between the high-stress first region and the low-stress second region, allowing the structure to maintain flexibility while protecting adhesion in critical areas.
Solution Approach 2:
Different regions of the second insulating layer are given different properties: the first region has high stress to maintain flexibility, while the second region has low stress to preserve adhesion. The depressed portion locally modifies the stress distribution to achieve this differentiated quality.
2Reliability
If the insulating layer is made thicker to improve coverage, then the adhesion is improved, but the stress applied to underlying layers increases, causing film separation
Solution Approach 1:
The second insulating layer is segmented into regions with different thicknesses and stress levels. The depressed portion creates a thinner second region that reduces stress on underlying layers, while the first region maintains sufficient thickness for adhesion.
Solution Approach 2:
The insulating layer exhibits local quality variations where the first region has greater thickness and stress for adhesion, while the second region has reduced thickness and stress to protect underlying layers from film separation.
3Area of moving object
If the display apparatus is designed for high resolution, then the aperture ratio can be increased, but the manufacturing precision requirements increase, reducing yield
Solution Approach 1:
The depressed portion is formed in the second insulating layer before subsequent manufacturing steps. This preliminary structural feature serves as a reference that facilitates precise alignment of the common electrode and other layers, thereby improving manufacturing precision and yield.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the reliability and yield of display apparatuses by improving adhesion and reducing stress, enabling high-resolution and high-definition displays with increased aperture ratio and extended lifetime.
Implementation Method 1
a photosensitive resin layer is formed over the EL layer; a mask is formed over the photosensitive resin layer; a first light exposure is performed on the photosensitive resin layer with the mask thereon; a first development is performed on the photosensitive resin layer to form an insulating layer
Implementation Method 2
The second insulating layer includes a depressed portion in a position overlapping with the region. The common electrode is provided over the second insulating layer
Data Source
AI summary
A highly reliable display apparatus is provided. The display apparatus includes a first light-emitting element, a second light-emitting element, a first insulating layer, and a second insulating layer. The first light-emitting element includes a first pixel electrode, a first EL layer over the first pixel electrode, and a common electrode over the first EL layer. The second light-emitting element includes a second pixel electrode, a second EL layer over the second pixel electrode, and the common electrode over the second EL layer. The first insulating layer covers the side surface and part of the top surface of the first EL layer and the side surface and part of the top surface of the second EL layer. The second insulating layer overlaps with part of the top surface of the first EL layer and part of the top surface of the second EL layer with the first insulating layer therebetween, includes a region positioned between the side surface of the first EL layer and the side surface of the second EL layer, and includes a depressed portion in a position overlapping with the region. The common electrode is provided over the second insulating layer.