Display Device Photolithography Maskless Island Patterning
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Solution Overview
Problem
Existing display devices face challenges in achieving high display quality, high resolution, high definition, and high reliability, particularly in manufacturing methods that result in low yield and poor accuracy due to the use of metal masks in forming island-shaped light-emitting layers.
Innovation Solution
The display device incorporates a manufacturing method that uses a photolithography process without a shadow mask, forming pixel electrodes independently for subpixels and processing the light-emitting layer into an island shape. This method includes the use of sacrificial layers and insulating layers to protect the light-emitting layers and reduce damage during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal masks are used in forming island-shaped light-emitting layers, then manufacturing process is simplified, but manufacturing precision and yield deteriorate
Solution Approach 1:
The patent replaces the mechanical shadow mask system with a photolithography-based chemical patterning system. Instead of using physical masks to define patterns, the invention uses photoresist coatings that are exposed to light through photomasks, followed by chemical development processes to form the island-shaped light-emitting layers. This substitution enables higher precision pattern formation while maintaining ease of manufacture through established semiconductor fabrication processes.
2Device complexity
If metal masks are used in forming island-shaped light-emitting layers, then device complexity is reduced, but manufacturing yield deteriorates
Solution Approach 1:
The invention replaces mechanical shadow mask alignment and attachment processes with a photolithography workflow that involves photoresist coating, UV exposure through photomasks, and chemical development. This approach eliminates mechanical mask handling errors and improves manufacturing yield through more reliable pattern transfer, while the overall process complexity remains manageable due to the maturity of photolithography techniques in semiconductor manufacturing.
3Manufacturing precision
If photolithography process without shadow mask is used, then manufacturing precision and yield improve, but device complexity increases
Solution Approach 1:
The patent replaces simple mechanical shadow mask deposition with a multi-step photolithography process including photoresist coating, UV exposure, chemical development, and etching. While this increases process steps, each step uses well-established semiconductor fabrication techniques that are highly controlled and repeatable, thereby achieving superior pattern formation accuracy without unmanageable complexity.
Solution Approach 2:
The invention introduces photoresist as an intermediary material that mediates between the photomask pattern and the final light-emitting layer structure. The photoresist absorbs UV light in exposed regions, undergoes chemical changes during development, and serves as a temporary mask during etching processes. This intermediary enables precise pattern transfer while keeping the overall process manageable through chemical rather than mechanical means.
4Productivity
If photolithography process without shadow mask is used, then manufacturing yield improves, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces simple mechanical shadow mask deposition with a multi-step photolithography process including photoresist coating, UV exposure, chemical development, and etching. While this increases process steps, each step uses well-established semiconductor fabrication techniques that are highly controlled and repeatable, thereby achieving superior pattern formation accuracy without unmanageable complexity.
Data Source
AI summary
A display device with high display quality is provided. The display device includes a first light-emitting device, a second light-emitting device placed adjacent to the first light-emitting device, and a first insulating layer. 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 a side surface of the first EL layer and part of a side surface of the second EL layer are placed to face each other. Part of the first insulating layer is placed 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 insulating layer is in contact with part of the top surface of the first EL layer and part of the top surface of the second EL layer.