Display Device Light-Emitting Layers Photolithography Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in achieving high reliability, high resolution, and high display quality, particularly in manufacturing processes that require precise patterning of light-emitting layers without using fine metal masks.
Innovation Solution
The display device employs a method where light-emitting devices of different colors are formed using a photolithography process without a shadow mask, incorporating a sacrificial layer to protect the light-emitting layer and reduce damage during manufacturing. This approach allows for precise island-shaped light-emitting layers to be formed, enhancing resolution and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fine metal masks are used for patterning light-emitting layers, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the fine metal mask from the manufacturing process entirely. Instead of using a mask for patterning, the light-emitting layer is formed directly on the pixel electrode through sequential deposition, and the bank structure is formed afterward to define the light-emitting region boundaries. This extraction eliminates the complexity associated with mask fabrication, alignment, and handling while maintaining patterning precision.
Solution Approach 2:
The pixel electrode is formed with a predetermined pattern before the light-emitting layer is deposited. The bank structure is formed after the light-emitting layer deposition but before final assembly. These preliminary actions establish the patterning framework without requiring a fine metal mask during the critical light-emitting layer formation step.
2Area of stationary object
If the distance between adjacent light-emitting devices is reduced to increase aperture ratio, then display quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The pixel electrode is formed with a predetermined pattern that defines the future light-emitting device boundaries. This preliminary patterning establishes precise spacing between adjacent devices before the light-emitting layer is deposited, enabling reduced pitch without requiring high-precision mask alignment. The bank structure is subsequently formed to further define and protect these closely-spaced regions.
Solution Approach 2:
The bank structure serves as an intermediary element that physically separates adjacent light-emitting devices. This bank acts as a protective barrier and structural intermediary that maintains precise spacing between devices, allowing the aperture ratio to be increased while the bank itself absorbs the manufacturing tolerance requirements rather than requiring direct precision between the light-emitting layers of adjacent devices.
3Ease of manufacture
If photolithography without shadow mask is used, then ease of manufacture is improved, but manufacturing precision may deteriorate
Solution Approach 1:
The shadow mask is completely removed from the manufacturing process. The light-emitting layer is deposited directly onto the pixel electrode through sequential deposition without requiring a shadow mask to define the pattern. This extraction dramatically simplifies the manufacturing process while the predetermined pixel electrode pattern and subsequent bank formation maintain the necessary patterning precision.
Solution Approach 2:
The mechanical shadow mask system is replaced with a sequential deposition process combined with bank structure formation. Instead of using a physical mask to block deposition material, the patent uses controlled sequential deposition followed by bank formation to define patterns, substituting a simpler mechanical process for the complex mask-based system.
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 method enables the production of highly reliable display devices with high resolution and high display quality, improving manufacturing yield and reducing the distance between adjacent light-emitting devices to achieve a high aperture ratio.
Implementation Method 1
a photolithography process without a shadow mask
Implementation Method 2
Light-emitting devices (also referred to as EL devices or EL elements) utilizing electroluminescence (hereinafter referred to as EL)
Data Source
AI summary
A highly reliable display device is provided. A first light-emitting device, a second light-emitting device positioned adjacent to the first light-emitting device, and a first insulating layer are included; the first light-emitting device 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 device includes a second pixel electrode, a second EL layer over the second pixel electrode, and the common electrode over the second EL layer; part of the first insulating layer is positioned at a position interposed between a side end portion of the first EL layer and a side end portion of the second EL layer; the first light-emitting device emits blue light; the second light-emitting device emits light of a color different from that from the first light-emitting device; the first EL layer includes a first light-emitting unit over the first pixel electrode, a first charge-generation layer over the first light-emitting unit, and a second light-emitting unit over the first charge-generation layer; and the second EL layer includes a third light-emitting unit over the second pixel electrode.