Donor Mask Light-to-Heat Conversion for OLED Deposition
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Solution Overview
Problem
Existing methods for manufacturing organic light-emitting display apparatuses often result in non-uniform quality and high defect rates due to variations in substrate alignment and deposition processes.
Innovation Solution
A donor mask with a base substrate, a light-to-heat conversion layer, a reflective layer, and a transferring layer is used, where the light-to-heat conversion layer and reflective layer are patterned with through holes, and a heat insulating layer is included to ensure precise alignment and uniform deposition of the emissive layer onto pixel electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form the emissive layer, then the manufacturing process is simple, but the quality is non-uniform and defect rates are high due to alignment variations
Solution Approach 1:
The emissive layer is pre-formed on the donor mask in a separate preparation step before the actual deposition onto the pixel electrodes. This preliminary formation allows for controlled transfer of the emissive layer material, ensuring uniform deposition and high manufacturing precision while managing the complexity through a staged process approach
Solution Approach 2:
The donor mask serves as an intermediary carrier that holds the pre-formed emissive layer. This intermediary structure enables precise alignment and controlled transfer of the emissive material to the pixel electrodes, resolving the contradiction between deposition uniformity and process complexity by decoupling the emissive layer formation from the final deposition step
2Productivity
If flash lamp light or laser beam is used to evaporate the transferring layer, then the emissive layer is transferred efficiently, but heat-induced defects may occur
Solution Approach 1:
The light-to-heat conversion layer is selectively positioned only in regions where emissive layer transfer is required, rather than uniformly across the entire donor mask. This localized configuration enables efficient evaporative transfer through flash lamp or laser irradiation while minimizing unnecessary heat exposure to surrounding areas, thereby preventing heat-induced defects
Solution Approach 2:
The conventional mechanical or thermal evaporation methods are replaced with optical field-based evaporation using flash lamp light or laser beams. This substitution allows for rapid, controlled evaporative transfer of the emissive layer with high productivity, while the brief duration and targeted nature of optical irradiation reduces the risk of heat-induced defects compared to sustained thermal processing
3Loss of substance
If the light-to-heat conversion layer is applied only on display transferring areas, then material wastage is minimized, but alignment precision may be compromised
Solution Approach 1:
The light-to-heat conversion layer is applied selectively only on the display transferring areas of the donor mask where emissive layer transfer is needed. This localized application minimizes material wastage by avoiding deposition on non-functional areas, while the precise definition of transfer boundaries and use of through holes maintain the required alignment precision
Solution Approach 2:
The donor mask is segmented into distinct functional regions: display transferring areas with the light-to-heat conversion layer, groove areas without the layer, and through hole regions. This segmentation allows material to be applied only where needed for transfer, reducing wastage while the through holes provide alignment references that maintain manufacturing precision
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 allows for the simultaneous manufacturing of organic light-emitting display apparatuses with reduced defect rates and uniform quality by ensuring consistent transfer of the emissive layer across multiple display areas, minimizing material wastage, and preventing heat-induced defects.
Implementation Method 1
a light-to-heat conversion layer on the base substrate... irradiating flash lamp light or a laser beam onto the base substrate of the donor mask, and evaporating, vaporizing, or sublimating at least a portion of the irradiated transferring layer
Implementation Method 2
a reflective layer between the base substrate and the light-to-heat conversion layer, the reflective layer being patterned to include a plurality of through holes in each of the plurality of display transferring areas
Implementation Method 3
evaporating, vaporizing, or sublimating at least a portion of the irradiated transferring layer
Implementation Method 4
evaporating, vaporizing, or sublimating at least a portion of the irradiated transferring layer
Data Source
AI summary
A method of manufacturing an organic light-emitting display apparatus including preparing a mother substrate that includes a plurality of display areas; forming a plurality of pixel electrodes on each of the display areas of the mother substrate; preparing a donor mask that includes a base substrate having a plurality of display transferring areas corresponding to the plurality of display areas, the base substrate including a groove between the display transferring areas, a light-to-heat conversion layer on the base substrate, and a reflective layer between the base substrate and the light-to-heat conversion layer and being patterned to include through holes in each of the display transferring areas; depositing a transferring layer on the light-to-heat conversion layer of the donor mask; aligning the mother substrate and the donor mask; and transferring portions of the transferring layer that overlie the through holes onto the pixel electrodes on the mother substrate.