Dual-Panel OELD Shadow Mask Dummy Pattern Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production yield of organic electroluminescent display (OELD) devices is reduced due to defects in the array elements and organic luminescent diodes formed on a single substrate, and the use of a shadow mask with uneven blocking portions affects the uniformity of the organic luminescent layer, leading to deteriorated displaying quality, especially in chip on glass (COG) type devices with limited space for dummy patterns.
Innovation Solution
A dual-panel type OELD device is fabricated using a shadow mask with a specific configuration where the dummy patterns are optimized to improve the uniformity of the normal patterns, allowing for a more uniform organic luminescent layer formation, and the substrates are arranged such that the power supply region has sufficient dummy patterns to enhance the displaying quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If both array elements and organic luminescent diodes are formed on a single substrate, then device integration is achieved, but production yield decreases due to defects in either component
Solution Approach 1:
The invention divides the device into two separate substrates: one substrate for array elements (TFTs) and another substrate for organic luminescent diodes. This segmentation allows independent fabrication and quality control of each component, preventing defects in one component from rendering the entire device defective, thereby improving production yield while maintaining device integration through subsequent assembly.
2Manufacturing precision
If dummy patterns are added to the shadow mask to improve uniformity of normal patterns, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The invention creates a copy of the pixel region pattern as dummy patterns around the periphery of the shadow mask. These dummy patterns replicate the same structural features as the normal patterns, allowing the etching process to maintain consistent conditions across all patterns. This copying approach improves manufacturing precision by ensuring uniform pattern formation while keeping the shadow mask design relatively simple and systematic.
3Manufacturing precision
If the shadow mask has sufficient dummy patterns, then uniformity of normal patterns improves, but the space required increases which is limited in COG type devices
Solution Approach 1:
The invention strategically places dummy patterns with different characteristics in different local regions of the shadow mask. Normal patterns in the pixel region have specific dimensions for functional pixels, while dummy patterns in peripheral regions are designed with matching structural features to maintain etching uniformity. This local quality differentiation allows the shadow mask to achieve pattern uniformity without requiring excessive space, as each region's patterns are optimized for its specific function.
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 improved uniformity of the organic luminescent layer leads to high-quality image display, increasing production yield and addressing the limitations of the COG type devices by ensuring sufficient dummy patterns for better pattern uniformity and reduced defects.
Implementation Method 1
an organic luminescent layer is formed using a shadow mask having a stripe pattern
Data Source
AI summary
An organic electroluminescent display (OELD) device comprises a first electrode on a first substrate having an active region and a non-active region at periphery of the active region, the active region including a plurality of pixel regions and the non-active region including a power supply region; an organic luminescent layer on the first electrode in the plurality of pixel regions; a first organic layer on the first electrode in the power supply region; a second organic layer on the first substrate in an outer region of the power supply region; a second electrode on the organic luminescent layer; a driving thin film transistor connected to the second electrode and formed on a second substrate; and a power supply terminal connected to the first organic layer and formed on the second substrate, wherein the first organic layer has substantially the same shape as the organic luminescent layer, and the second organic layer has substantially a different shape from the organic luminescent layer.