Transparent Substrate Coating Control for Drift Compensation
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Solution Overview
Problem
Existing feedback methods in coating processes for transparent substrates fail to manage accuracy and precision drifts in measuring instruments, are ineffective against environmental changes, and can be trapped in local optimal solutions, leading to out-of-specification products.
Innovation Solution
A method utilizing multiple mathematical prediction models trained on manufacturing history data to adjust coating process parameters, allowing for real-time compensation of drifts and environmental changes, and optimizing parameters simultaneously to achieve targeted quality functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional feedback methods are used to control coating parameters, then real-time monitoring is achieved, but accuracy and precision drifts in measuring instruments cannot be managed
Solution Approach 1:
The patent implements a feedback mechanism where measured optical properties are continuously compared against target values, and coating parameters are adjusted based on the deviations. This closed-loop control system compensates for measuring instrument drifts by using the feedback information to correct both the measurement references and the coating process parameters simultaneously
Solution Approach 2:
The system changes multiple coating parameters simultaneously based on measured deviations, rather than adjusting single parameters sequentially. This multi-parameter adjustment approach allows the system to compensate for measurement drifts by finding optimal parameter combinations that account for instrument accuracy changes
2Ease of operation
If single parameter adjustment is used in feedback control, then simple control logic is maintained, but local optimal solutions are trapped and specification compliance is reduced
Solution Approach 1:
The patent transitions from single-parameter adjustment to multi-parameter simultaneous adjustment, adding dimensional complexity to the control space. By adjusting multiple coating parameters concurrently based on measured deviations, the system explores a higher-dimensional solution space that avoids local optima while maintaining specification compliance
3Reliability
If extensive measuring devices are deployed for real-time monitoring, then continuous quality control is achieved, but system complexity and costs increase rapidly
Solution Approach 1:
The system uses a universal feedback mechanism that can operate with various types of measuring devices and coating processes. The feedback control algorithm is designed to be adaptable to different measurement instruments and coating methods, reducing the need for specialized complex systems for each application
4Measurement precision
If off-process measurements are performed on collected samples, then quality verification is achieved, but production time and disruption increase
Solution Approach 1:
The system implements continuous in-process measurements during the coating operation, allowing quality verification to occur without interrupting the coating process. The feedback control operates continuously, adjusting parameters in real-time while the coating is being applied, thereby maintaining both quality verification and production continuity
Data Source
AI summary
A method for adjusting at least two parameters of a coating process to manufacture a coated transparent substrate including a multi-layered coating according to a targeted value for at least one quality function for the coated transparent substrate. The method relies on a set of different mathematical prediction models in the training procedure, which, once trained, when they are used either sequentially, alternatively or in parallel, during the prediction procedure, allow to counteract or counterbalance drifts that may potentially occur from one of them. Outstanding benefits are that misbehaviours of current feedback methods may be prevented, that changes in the local atmosphere of deposit cells, and in turn in the chemistry of coated layers, which may occur from temperature and/or humidity variation, may be compensated, and that more than one coating process parameters may be adjusted at the same time.