Display Device Second EL Layer Electron Injection Optimization
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Solution Overview
Problem
Current display technologies face challenges in achieving high resolution, high display quality, and high contrast while maintaining a reliable manufacturing process, particularly in devices like smartphones, tablets, and virtual/augmented reality systems.
Innovation Solution
A display device with a novel structure incorporating a light-emitting element and a connection portion, where the second EL layer has a specific thickness and area of overlap, and contains a substance with high electron-injection properties, allowing for fine patterning without shadow masks, enabling high-resolution and high-aperture ratio displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing processes are used for display devices, then manufacturing reliability is maintained, but achieving high resolution and high aperture ratio becomes difficult
Solution Approach 1:
The patent extracts and removes the shadow mask component from the manufacturing process entirely. Instead of using shadow masks to define pixel patterns, the invention forms electrodes and EL layers directly in their final positions through selective deposition and formation processes, eliminating the need for mask alignment and removal steps.
Solution Approach 2:
The patent performs preliminary patterning actions during the deposition process itself. Electrodes and EL layers are formed with precise spatial distribution from the beginning through controlled deposition on patterned substrates, rather than requiring subsequent patterning steps after full-layer deposition.
2Manufacturing precision
If shadow masks are used for patterning, then manufacturing process is simpler, but resolution and aperture ratio are limited
Solution Approach 1:
The shadow mask is completely extracted from the system. The patent achieves patterning through direct selective deposition and formation processes where materials are deposited only in required locations from the start, eliminating mask-related complexity and enabling higher resolution without sacrificing manufacturing simplicity.
Solution Approach 2:
The mechanical shadow mask system is replaced with a field-based selective deposition approach. Instead of physically blocking deposition with a mask, the patent uses electric field control and patterned substrate preparation to guide material deposition precisely where needed, achieving superior pattern precision.
3Reliability
If the second EL layer is made thinner to improve electron injection, then electron-injection property improves, but layer stability may be compromised
Solution Approach 1:
The patent optimizes the thickness parameter of the second EL layer to a specific range (0.5-1.5 nm) that balances electron injection performance with structural stability. This precise parameter control allows the thin layer to provide sufficient electron injection while maintaining adequate mechanical and electrical stability for reliable device operation.
Solution Approach 2:
The patent uses composite material structures in the EL layers, combining organic compounds with specific molecular characteristics that provide both high electron mobility for injection and structural integrity. The multi-component organic materials deliver dual functionality of electron transport and layer stability simultaneously.
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 enables the production of display devices with high resolution, high display quality, and high contrast, while simplifying the manufacturing process and reducing the area of non-light-emitting regions, thus achieving a highly reliable and efficient display solution.
Implementation Method 1
The second EL layer contains a substance with a high electron-injection property
Implementation Method 2
By applying a voltage to this element, light emission can be obtained from the light-emitting organic compound
Data Source
AI summary
A display device with both high display quality and high resolution is provided. The display device includes a light-emitting element and a connection portion. The connection portion is provided along an outer periphery of a display region where the light-emitting element is provided. The light-emitting element includes a pixel electrode, a first EL layer over the pixel electrode, a second EL layer over the first EL layer, and a common electrode over the second EL layer. The connection portion includes a connection electrode, a second EL layer over the connection electrode, and the common electrode over the second EL layer. The second EL layer includes a first region in contact with the connection electrode and a second region in contact with the common electrode. The area of a region where the first region and the second region overlap with each other in a top view is greater than or equal to 40000 square micrometers. The second EL layer includes a region where the film thickness is greater than or equal to 0.5 nm and less than or equal to 1.5 nm. The second EL layer contains a substance with a high electron-injection property.