Infrared Substrate Distance Detection in Coating Chambers
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Solution Overview
Problem
Existing coating processes face challenges in precisely detecting the distance between substrates during in-line coating under vacuum, especially when optical sensors require display windows that become opaque due to coating, leading to inefficient evaporation and increased maintenance costs.
Innovation Solution
A coating chamber equipped with a gas-tight unit having two windows for infrared (IR) radiation, allowing IR radiation from a limited area to be detected, and a processor to determine substrate distance based on IR radiation intensity differences between substrates and surroundings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors with display windows are used to detect substrate position, then measurement precision is improved, but the display windows become opaque due to coating deposition, causing loss of measurement function
Solution Approach 1:
The patent changes the wavelength parameter of the detection radiation from visible light to infrared radiation. Coating materials that are opaque to visible light are often transparent to infrared radiation, allowing the display window to remain functional for detection purposes even after coating deposition, thus maintaining measurement precision and reliability
Solution Approach 2:
The patent introduces an infrared-transparent window material as an intermediary between the coating area and the detector. This window material allows infrared radiation to pass through while blocking visible light, enabling continuous substrate position detection without the window becoming opaque due to coating material deposition
2Productivity
If substrates are transported closer together to improve evaporation efficiency, then productivity is improved, but the risk of substrate collisions increases under thermal expansion conditions
Solution Approach 1:
The patent implements a feedback control system where the infrared detector continuously monitors substrate position and provides real-time data to the control unit. The control unit adjusts transport parameters based on detected position and temperature data, enabling safe operation at reduced substrate spacing while preventing collisions through active monitoring and control
Solution Approach 2:
The patent performs preliminary detection of substrate position and temperature before potential collision scenarios occur. By continuously monitoring substrate locations and thermal expansion, the system can take preventive actions to maintain safe spacing while maximizing evaporation efficiency
3Reliability
If display windows are heated to high temperatures to prevent coating material condensation, then measurement function is maintained, but energy consumption increases and thermal damage risk increases
Solution Approach 1:
The patent changes the operational temperature parameter of the display window by using infrared radiation detection instead of visible light detection. This eliminates the need to heat the window to high temperatures, as infrared detection can function at lower temperatures, thereby reducing energy consumption and thermal damage risk while maintaining measurement reliability
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
Enables precise and reliable detection of substrate distance with minimal maintenance, improving evaporation efficiency and preventing substrate collisions, even under conditions of thermal expansion and high-temperature coating materials.
Implementation Method 1
a detector for IR radiation, which is arranged in such a way that IR radiation from the coating area can impinge on the detector through the windows of the gas-tight unit
Implementation Method 2
The first chamber wall comprises a gas-tight unit with a first window for infrared radiation (IR radiation)
Data Source
AI summary
The present invention relates to a coating plant and a method for coating substrates with distance detection for the substrates.