LED Transfer Donor Substrate With Stable Alignment Marks
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Solution Overview
Problem
The existing donor substrates used in LED transfer processes face challenges with alignment mark identification due to unclear edges and deformation caused by external impacts and resin layer stretching, leading to increased process time and potential alignment errors.
Innovation Solution
A donor substrate with a base substrate, a resin layer, and alignment marks formed directly on the substrate surface, which are easily identifiable and less prone to deformation, along with first and second protrusions to support LED transfer and reduce damage from external impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If alignment protrusions are formed using PDMS coating and curing process, then the donor substrate can be reused in primary and secondary transfer processes, but the edge of the alignment protrusion becomes rounded and unclear, making it difficult to identify
Solution Approach 1:
The alignment mark is formed with a different material having distinct optical properties (different refractive index or color) from the surrounding PDMS resin layer. This creates a clear visual contrast that enables easy identification of the alignment mark position, resolving the issue of rounded and unclear edges while maintaining the reusability of the donor substrate.
2Productivity
If the donor substrate is continuously used in primary and secondary transfer processes, then productivity is improved, but the alignment key may be damaged or its position may be deformed due to external impact and friction
Solution Approach 1:
The alignment mark is formed using a material with different mechanical properties (higher hardness or elasticity) than the surrounding PDMS resin layer. This localized difference in material properties allows the alignment mark to resist damage and positional deformation from external impacts and friction during repeated use, while the rest of the soft PDMS substrate maintains its flexibility and transfer functionality.
3Ease of manufacture
If alignment protrusions are formed from the same material as the resin layer, then the manufacturing process is simplified, but the contrast ratio between alignment marks and surrounding components is reduced
Solution Approach 1:
A material with distinct optical properties is used to form the alignment mark, creating a clear visual contrast against the PDMS resin layer. This enables easy identification of the alignment mark position during alignment processes, resolving the visibility issue while maintaining manufacturing simplicity through direct coating or printing methods.
Data Source
AI summary
A donor substrate according to an exemplary embodiment of the present disclosure comprises a base substrate, a resin layer disposed on one surface of the base substrate, a plurality of first protrusions disposed on the resin layer, and an alignment mark disposed on the base substrate. Therefore, as the alignment mark is disposed on the surface of the base substrate, it is possible to reduce a change in position of the alignment mark caused by the resin layer.