Metal Plate Flatness Control for Accurate Metal Mask Through-Holes
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Solution Overview
Problem
The wavy shape of metal plates used in manufacturing metal masks for high-definition organic EL display devices leads to variations in through-hole positioning accuracy, affecting the precision of pixel formation.
Innovation Solution
A metal plate with controlled differential expansion rate, where the maximum inclination in the central portion is 1.8 × 10^-3/m or less, and the central portion occupies 80% of the width direction, is used to manufacture metal masks with improved positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the metal plate is rolled more thinly to improve through-hole dimensional accuracy, then the dimensional accuracy of through-holes is improved, but a wavy shape appears in the metal plate
Solution Approach 1:
The invention changes the physical parameters of the metal plate by controlling the differential expansion rate E to be 1.8×10^-3/m or less in the central portion. This parameter control prevents the wavy shape that normally occurs when rolling thin metal plates, while maintaining the dimensional accuracy of through-holes. The differential expansion rate serves as a key parameter that links the rolling process outcomes.
2Manufacturing precision
If the metal plate is made flat to improve positional accuracy, then the positional accuracy of through-holes is improved, but the manufacturing complexity increases due to additional processing steps
Solution Approach 1:
The invention performs the flattening action preliminarily during the rolling process itself by controlling the differential expansion rate E. Instead of adding separate flattening steps after rolling, the invention incorporates the flatness control into the rolling process parameters, thereby achieving the desired flatness without increasing manufacturing process complexity.
Data Source
Figure 1A
Figure 1B(a)~1B(d)
Figure 1C
AI summary
Provided is a metal plate to be used for manufacturing a metal mask. In a graph in which an arbitrary position n in a width direction of the metal plate is plotted on a horizontal axis and in which a differential expansion rate En in a unit length L0 in a longitudinal direction is plotted on a vertical axis, a maximum inclination of the differential expansion rate E in a central portion in the width direction is 1.8 × 10-3/m or less, and the central portion is a portion that occupies 80% in the width direction excluding both side portions that each occupy 10% in the width direction.