Vapor Deposition Mask Alignment Marks for Display Manufacturing
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Solution Overview
Problem
The challenge in manufacturing vapor deposition masks for high-definition organic electroluminescent (EL) display devices is accurately joining an intermediate to a support to enhance strength, while maintaining positional accuracy and preventing misregistration due to thermal expansion coefficient differences between mask components and the substrate.
Innovation Solution
A vapor deposition mask design featuring a mask main body with a first alignment mark and a support with a second alignment mark, where the alignment marks overlap in plan view, with the support being larger, ensures accurate positioning and alignment, allowing for precise deposition of vapor materials onto the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an intermediate is stacked on a support to reinforce the vapor deposition mask, then strength is enhanced, but joining accuracy between the intermediate and support deteriorates
Solution Approach 1:
Alignment marks are formed on both the intermediate and support before the joining process. These pre-formed marks serve as guides during assembly, enabling accurate alignment and joining of the intermediate to the support, thus resolving the contradiction between enhanced strength through stacking and maintaining joining accuracy.
2Ease of manufacture
If alignment marks of equal size are used, then positioning is simplified, but misregistration occurs due to thermal expansion coefficient differences
Solution Approach 1:
The alignment mark on the intermediate is designed to be larger than the alignment mark on the support. This asymmetric design compensates for thermal expansion differences between the intermediate and support during vapor deposition, preventing misregistration while maintaining positioning accuracy.
3Productivity
If the vapor deposition mask is made thinner for high-definition display, then pixel density increases, but mask strength deteriorates
Solution Approach 1:
The vapor deposition mask is divided into two separate components: a thin intermediate containing the through-holes for high pixel density, and a separate support providing mechanical strength. This segmentation allows the intermediate to be made thinner for high-definition display while the support compensates for strength requirements.
Solution Approach 2:
The thin intermediate and the strong support are joined together through alignment marks to form a composite vapor deposition mask structure. This merging combines the advantages of both components: the thin intermediate enables high pixel density while the support provides necessary strength.
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 design enhances the positional accuracy of vapor deposition, preventing luminance unevenness and non-lighting issues in organic EL substrates by ensuring accurate alignment and adherence of the mask components, thereby improving the manufacturing process for high-definition displays.
Implementation Method 1
the first alignment mark and the second alignment mark are provided at such positions as to overlap with each other in plan view
Implementation Method 2
vapor-depositing an organic material onto the organic EL substrate
Data Source
AI summary
A vapor deposition mask includes a mask main body and a support joined to the mask main body. The mask main body has a first alignment mark whereas the support has a second alignment mark. The first alignment mark and the second alignment are provided at such positions as to overlap with each other in plan view, and either one of the alignment marks is larger than the other of the alignment marks.