Vacuum Coating Sensor Emission Rate Control
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Solution Overview
Problem
The service life of sensors in vacuum coating systems is limited due to coating material accumulation, leading to frequent sensor replacements and interruptions in the coating process, which reduces the efficiency and duration of uninterrupted production.
Innovation Solution
The method involves determining the actual emission rate of the coating material by taking sensor responses before and after exposure to the coating material, eliminating the need for waiting for thermal equilibrium, thereby reducing measurement time and extending the sensor's operational life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is exposed to coating material for measurement, then the emission rate can be determined, but the sensor accumulates coating material which limits its service life
Solution Approach 1:
The sensor is exposed to the coating material in periodic measurement cycles rather than continuously. Between measurements, the sensor is protected from coating material exposure. This periodic exposure allows the sensor to perform measurements while limiting cumulative coating accumulation, thereby extending service life while maintaining measurement capability.
Solution Approach 2:
The measurement function is extracted from continuous operation and performed only during specific measurement cycles. The sensor is removed from the coating material stream during non-measurement periods, separating the measurement function from continuous exposure and reducing coating accumulation.
2Measurement precision
If the sensor waits for thermal equilibrium before measurement, then measurement accuracy improves, but measurement time increases reducing productivity
Solution Approach 1:
The sensor is pre-heated to the target temperature before entering the coating material stream for measurement. This preliminary heating action ensures the sensor reaches thermal equilibrium quickly during the measurement cycle, eliminating the need for extended waiting time and allowing faster measurements while maintaining accuracy.
Solution Approach 2:
The thermal parameters of the sensor are changed by pre-heating it to the desired operating temperature before measurement. This parameter change (temperature) is performed in advance, allowing the sensor to maintain thermal equilibrium throughout the measurement process without requiring extended measurement time.
3Measurement precision
If the sensor is frequently replaced due to coating accumulation, then measurement accuracy is maintained, but production interruptions increase
Solution Approach 1:
The sensor operates in periodic measurement cycles with protection phases in between, which slows down coating accumulation. This extends the interval between sensor replacements, reducing production interruptions while maintaining measurement accuracy during each measurement cycle.
Solution Approach 2:
The patent accepts that sensors have limited service lives due to coating accumulation, but by using periodic measurement and protection strategies, the effective service life is extended. When replacement is necessary, it causes minimal production disruption because the extended service life reduces replacement frequency.
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 approach significantly extends the service life of the vacuum coating system by allowing multiple measurements within a given time frame, reducing downtime, and improving the efficiency of the coating process.
Implementation Method 1
a sensor such as an oscillating quartz (e.g. in combination with an associated oscillator) may be used, which is exposed to the emitted coating material. For example, a resonant frequency of the quartz oscillator changes depending on the mass of the coating material with which the sensor is coated.
Implementation Method 2
coating may be carried out, for example, by chemical vapor deposition or by physical vapor deposition, e.g. within a vacuum chamber
Data Source
AI summary
Disclosed herein are devices, systems, and methods for coating a substrate. The method includes determining a data variable representing an actual state of a rate at which a coating material is emitted based on: a first response of a sensor before the sensor is exposed to the coating material and preferably heated thereby. The data variable is also determined based on a second response of the sensor after the sensor has been exposed to the coating material and preferably cools. The method also includes controlling a control element configured to affect the rate based on the data variable.