Display Apparatus Tapered Insulating Layers
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Solution Overview
Problem
Current display apparatuses face challenges in achieving high-resolution, high-definition, and highly reliable displays, particularly in manufacturing processes that require precise patterning of light-emitting layers without shadow masks, which can lead to deviations in shape and position, reduced thickness variations, and lower manufacturing yield.
Innovation Solution
The display apparatus incorporates a method using photolithography without a shadow mask to form island-shaped light-emitting layers, with insulating layers covering side surfaces to prevent short circuits and damage, and a common electrode shared by light-emitting devices of different colors, allowing for precise control of layer thickness and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow masks are used to pattern light-emitting layers, then manufacturing process is simpler, but positioning accuracy deteriorates and shape deviation increases
Solution Approach 1:
The invention extracts and removes the shadow mask from the manufacturing process entirely. Instead of using a shadow mask to define patterns, the method forms light-emitting layers directly on pixel electrodes through selective deposition or solution processing, eliminating the shadow mask and its associated positioning errors while simplifying the overall manufacturing process.
Solution Approach 2:
The invention introduces insulating layers as intermediary structures between the pixel electrode and light-emitting layer. These insulating layers with tapered side surfaces act as self-aligned masks and protective barriers, enabling precise patterning without external shadow masks while preventing short circuits and material damage during fabrication.
2Reliability
If insulating layers with vertical side surfaces are used, then short circuit prevention is adequate, but layer thickness uniformity deteriorates and manufacturing yield decreases
Solution Approach 1:
The invention employs insulating layers with asymmetric tapered side surfaces instead of vertical walls. The tapered geometry (with side wall angles between 45-85 degrees) creates self-aligning features that guide subsequent material deposition and patterning processes, improving thickness uniformity and positioning accuracy while maintaining effective short circuit prevention through the insulating barrier.
3Reliability
If separate electrodes are used for each light-emitting device, then device independence is ensured, but manufacturing complexity increases and yield decreases
Solution Approach 1:
The invention merges multiple individual electrode structures into a single shared common electrode that serves multiple light-emitting devices. This common electrode is positioned beneath the insulating layers and light-emitting layers, providing electrical connection to multiple emitters simultaneously. The approach maintains device independence through insulating layer separation while achieving economies of scale in manufacturing and improving overall yield.
Solution Approach 2:
The common electrode serves multiple functions: it acts as the cathode (or anode) for multiple light-emitting devices, provides a shared electrical connection point, and serves as a structural base layer for the entire display structure. This multi-functional design reduces the total number of electrode components and simplifies the manufacturing process while maintaining reliable operation of individual devices.
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
This approach enables the production of high-resolution display apparatuses with improved aperture ratios, reduced manufacturing defects, and increased reliability, achieving higher display quality and longer device lifetime.
Implementation Method 1
Light-emitting devices (also referred to as EL devices or EL elements) utilizing electroluminescence (hereinafter referred to as EL)
Data Source
AI summary
A display apparatus with high display quality is provided. The display apparatus includes a first light-emitting device, a second light-emitting device, a first insulating layer, and a second insulating layer. The first light-emitting device includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, and a common electrode over the first light-emitting layer. The second light-emitting device includes a second pixel electrode, a second light-emitting layer over the second pixel electrode, and the common electrode over the second light-emitting layer. The first insulating layer covers a side surface and part of a top surface of the first light-emitting layer and a side surface and part of a top surface of the second light-emitting layer. The second insulating layer overlaps with the side surface and the part of the top surface of the first light-emitting layer and the side surface and the part of the top surface of the second light-emitting layer with the first insulating layer therebetween. The common electrode covers the second insulating layer. In a cross-sectional view, an end portion of the second insulating layer has a tapered shape with a taper angle less than 90°. The second insulating layer covers at least part of a side surface of the first insulating layer.