Display Substrate Alignment via Fiducial Mark Expansion Detection
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Solution Overview
Problem
The challenge in manufacturing display elements, such as organic electroluminescence (EL) and liquid crystal display elements, lies in accurately aligning and processing flexible sheet substrates that undergo expansion and contraction during the manufacturing process, affecting product yield due to issues like heat-induced deformation and sliding between transport rollers.
Innovation Solution
A manufacturing apparatus and method that utilize a first and second alignment system to detect fiducial marks, calculate substrate expansion/contraction, and adjust processing accordingly, ensuring precise positioning and transport speed control to maintain accurate alignment and coating positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image recognition cameras are used to align the flexible sheet substrate and mask, then alignment capability is provided, but the system complexity increases and cannot fully compensate for substrate expansion/contraction
Solution Approach 1:
The patent changes the measurement parameters by detecting substrate expansion and contraction rates through multiple alignment marks and camera systems. By monitoring positional changes of fiducial marks before and after substrate processing, the system calculates expansion/contraction parameters and uses this data to correct alignment positions, thereby improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The patent implements a feedback mechanism where the positions of alignment marks are continuously detected by camera systems, expansion/contraction rates are calculated from these detections, and correction values are fed back to adjust the alignment between substrate and mask. This closed-loop feedback system enables dynamic compensation for substrate deformation, maintaining high alignment accuracy
2Ease of manufacture
If the substrate is processed without considering expansion and contraction, then the manufacturing process is simpler, but the positioning accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting and calculating substrate expansion and contraction rates before the actual coating or processing step. Alignment marks are positioned and measured in advance, allowing the system to pre-correct alignment data based on predicted substrate deformation. This enables simple processing steps to achieve high precision by preparing correction data beforehand
Solution Approach 2:
The patent introduces alignment marks as intermediary reference elements that mediate between the substrate and the measurement system. These fiducial marks serve as intermediaries to detect substrate deformation without interfering with the actual substrate processing. The marks translate complex substrate expansion/contraction into measurable positional changes that can be compensated through calculation
3Measurement precision
If multiple alignment systems are arrayed to detect expansion and contraction, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The patent segments the measurement function by distributing multiple alignment marks across the substrate surface and using separate camera systems to detect each mark's position. Rather than using one complex high-resolution system, multiple simpler detection points work together to provide comprehensive expansion/contraction measurement. This segmentation allows accurate detection of non-uniform substrate deformation while keeping individual detection components relatively simple
Data Source
AI summary
The display element manufacturing apparatus has a transporting part, which transports a substrate in a first direction, a first alignment system, which detects fiducial marks, a second alignment system, which is arranged at a prescribed distance from the first alignment system in the first direction and detects fiducial marks, calculating parts, which detect the fiducial marks and calculate the expansion/contraction of the substrate in the first direction or the transport speed of the substrate, and a processing part, which processes a prescribed position of the substrate based on at least one of the expansion/contraction of the substrate in the first direction or the transport speed of the substrate and the fiducial marks.