Display Sub-Pixel Trenches Prevent Leakage Current
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Solution Overview
Problem
High-resolution light emitting display apparatuses face challenges in maintaining image quality due to shadow defects and leakage current issues, particularly in head-mounted displays, where precise alignment of fine metal masks is difficult, leading to mixed color emission and decreased display quality.
Innovation Solution
The solution involves forming first and second trenches and fences between sub-pixels to prevent leakage current and mixed color emission, using a substrate with adjacent sub-pixels and electrodes, and a light emitting layer disposed over the trenches, which helps in reducing shadow defects and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the spacing between sub-pixels is narrowed to achieve high resolution, then the resolution is improved, but unintended light emission occurs due to leakage current from adjacent sub-pixels
Solution Approach 1:
The patent divides the display structure into isolated sub-pixel units by introducing trenches between adjacent sub-pixels. This segmentation physically separates the sub-pixels, preventing leakage current from spreading to adjacent sub-pixels while maintaining narrow spacing for high resolution.
Solution Approach 2:
The patent introduces an intermediary structure (trench filled with insulating material) between adjacent sub-pixels to block the harmful leakage current. This intermediary layer acts as a barrier that prevents electrical interference between sub-pixels without affecting the overall compact structure.
2Manufacturing precision
If a fine metal mask is used to deposit light emitting layer for each sub-pixel, then the color precision is improved, but the display apparatus may be damaged due to contact with the mask
Solution Approach 1:
The patent performs preliminary patterning of the light emitting layer material before final deposition. By pre-forming patterns and using transfer printing techniques, the need for direct contact with fine metal masks during deposition is eliminated, preventing device damage while maintaining precise color placement.
Solution Approach 2:
The patent replaces the mechanical contact-based fine metal mask deposition system with a contactless deposition method. This substitution eliminates the mechanical interaction that causes device damage while achieving the same precision in light emitting layer placement for accurate color rendering.
3Ease of operation
If the gap between mask and substrate is large, then the mask can be easily positioned, but the light emitting layer material is deposited over a larger area causing shadow defects
Solution Approach 1:
The patent performs preliminary patterning and material preparation steps that allow for larger mask-substrate gaps during deposition. By pre-forming patterns and using transfer techniques, the system can tolerate larger gaps without compromising deposition accuracy, as the material is transferred rather than directly deposited from a close-proximity mask.
Solution Approach 2:
The patent introduces an intermediary transfer layer or mechanism between the mask and substrate that enables material transfer over larger gaps. This intermediary system decouples the positioning ease of large gaps from the deposition precision requirement, allowing both conditions to be satisfied 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
This configuration effectively reduces display quality degradation by preventing leakage current and mixed color emission, enhancing the brightness and resolution of the display apparatus, especially in high-resolution applications like head-mounted displays.
Implementation Method 1
a light emitting display apparatus (LED) has a structure in which a light emitting layer is formed between an anode electrode and a cathode electrode, and displays an image by emitting light due to an electric field between the two electrodes
Implementation Method 2
The light emitting layer may be made of an organic material or inorganic material that generates excitons by combining electrons and holes, and emits light when the generated excitons fall from the excited state to the ground state
Data Source
AI summary
A display apparatus includes a substrate including a first sub-pixel and a second sub-pixel disposed adjacent to each other; a first electrode disposed in each of the first sub-pixel and the second sub-pixel on the substrate; a first light emitting layer on the first electrode in the first sub-pixel and a second light emitting layer on the first electrode in the second sub-pixel; a first trench formed between the first electrode of the first sub-pixel and the first electrode of the second sub-pixel; and a second trench formed between the first electrode of the first sub-pixel and the first trench, wherein the first light emitting layer and the second light emitting layer are disposed over the first trench.