Multi-Layer Zinc Bank Structure for Maskless Display Pixel Formation
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Solution Overview
Problem
The challenge lies in creating a display device for glasses-type virtual and augmented reality applications that can achieve high pixel integration density without the need for a mask process, while minimizing damage to pixel electrodes during plasma exposure and etching processes.
Innovation Solution
A display device structure is proposed with a first pixel electrode, an inorganic insulating layer, a light emitting layer, and bank layers made of zinc-containing materials, where the side surfaces of the bank layers are strategically designed to protrude, allowing for the formation of light emitting elements in each emission area without a mask process and reducing damage during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the display device is implemented in a very small size with high pixel integration degree, then the resolution is improved, but the area of emission areas is reduced making it difficult to form light emitting elements separated through mask process
Solution Approach 1:
The bank structure is divided into multiple layers (first bank layer, second bank layer, third bank layer) with progressively protruding side surfaces. This segmentation allows each layer to perform specific functions: the first bank layer defines emission area boundaries, while the second and third bank layers with protruding side surfaces create physical separation between adjacent light emitting elements, enabling element formation without mask processes.
Solution Approach 2:
The solution transitions from a two-dimensional planar mask process to a three-dimensional bank structure with protruding side surfaces. The multi-layered bank structure extends vertically and horizontally, using the protruding side surfaces to define separation regions between light emitting elements, thereby eliminating the need for mask processes while maintaining high pixel integration density.
2Ease of manufacture
If plasma exposure or etching processes are performed during manufacturing, then the light emitting elements can be formed, but damage to pixel electrodes occurs
Solution Approach 1:
The inorganic insulating layer serves as an intermediary protective barrier between the pixel electrode and the plasma exposure/etching processes. This layer shields the pixel electrode from direct exposure to harmful plasma and etchants while allowing the formation of light emitting elements in the emission areas through controlled etching of the bank structure.
Solution Approach 2:
The bank structure with protruding side surfaces is formed in advance to create physical separation and protective overhangs. These protruding structures prevent plasma and etchants from directly reaching the pixel electrodes during the light emitting element formation process, thereby preemptively protecting against electrode damage before the actual etching occurs.
3Ease of manufacture
If the side surfaces of bank layers are designed to protrude, then light emitting elements can be formed without mask process, but the manufacturing process complexity increases
Solution Approach 1:
Multiple bank layers (first, second, and third bank layers) are merged into a single integrated bank structure with progressively protruding side surfaces. This unified structure performs multiple functions simultaneously: defining emission area boundaries, creating physical separation between light emitting elements, and providing protective overhangs. The merging of these functions into one structure reduces overall manufacturing complexity compared to using separate components for each function.
Data Source
AI summary
A display device includes an emission area including a pixel electrode, an inorganic layer exposing the pixel electrode to outside the inorganic layer, a light emitting layer and a common electrode, and a bank layer on the inorganic layer and in which an opening is defined corresponding to the emission area. The bank layer includes a first bank layer including zinc, a second bank layer on the first bank layer, a third bank layer on the second bank layer, each of the first bank layer, the second bank layer and the third bank layer including a side surface which defines a portion of the opening in the bank layer; the side surface of the first bank layer recessed from the side surface of the second bank layer in a direction away from the first emission area; and the side surface of the second bank layer recessed from the side surface of the first bank layer in a direction away from the emission area.