UV Sensor In-Situ Calibration via Periodic Shutter Control
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Solution Overview
Problem
Conventional UV sensor calibration methods in UV irradiation apparatuses are inefficient due to external calibration processes, which lead to inaccuracies and reduced productivity, as the built-in UV sensors degrade over time and require frequent external calibration using a separate UV sensor exposed to different environments.
Innovation Solution
An in-situ calibration method where a second UV sensor, exposed less frequently to UV light, calibrates the built-in UV sensor within the UV unit, eliminating external calibration errors and allowing for simultaneous measurement, thereby improving accuracy and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external calibration is used with a separate UV sensor, then calibration can be performed, but measurement accuracy deteriorates due to environmental differences and sensor degradation
Solution Approach 1:
The patent merges the calibration sensor and the feedback sensor into a single sensor unit, eliminating the need for external calibration equipment. This unified sensor performs both real-time feedback measurement and periodic calibration functions, ensuring that both measurements are taken under identical environmental conditions and by the same sensor, thereby eliminating calibration accuracy deterioration.
Solution Approach 2:
The patent implements periodic calibration by controlling the shutter to expose the sensor to calibration light at predetermined intervals during substrate processing. This periodic exposure allows the sensor to self-calibrate using an internal standard light source while maintaining continuous monitoring capabilities, addressing sensor degradation through regular recalibration without stopping production.
2Measurement precision
If external calibration is performed by detaching the UV unit, then sensor calibration can be conducted, but productivity decreases due to processing time loss
Solution Approach 1:
The patent enables the sensor to perform self-calibration by incorporating an internal standard light source and control mechanism. The sensor automatically calibrates itself during substrate processing by comparing measurements taken with the shutter closed (reference measurement) versus shutter open (actual UV light measurement), eliminating the need for external calibration equipment and manual intervention, thereby maintaining high productivity.
Solution Approach 2:
The patent maintains continuous substrate processing while performing calibration operations. The periodic calibration is integrated into the normal processing cycle, allowing calibration to occur without stopping the UV irradiation process or removing substrates, thus ensuring continuous productive operation while maintaining measurement accuracy.
3Ease of operation
If the built-in UV sensor is exposed to UV light continuously for feedback, then real-time monitoring is achieved, but sensor degradation accelerates
Solution Approach 1:
The patent uses periodic shutter control to limit the feedback sensor's exposure to UV light. The shutter remains closed during most of the processing time and only opens periodically to allow calibration measurements. This periodic exposure maintains real-time monitoring capability through the control system while significantly reducing cumulative UV damage to the sensor, extending its operational lifespan.
4Reliability
If a shutter is added to control UV exposure, then sensor degradation is reduced, but device complexity increases
Solution Approach 1:
The patent designs the shutter mechanism to serve multiple functions: it controls UV light exposure to the feedback sensor during normal operation, enables periodic calibration by exposing the calibration sensor, and acts as a reference measurement chamber when closed. This multi-functionality justifies the added complexity by eliminating the need for separate calibration equipment and reducing sensor degradation, providing net system simplification.
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
The in-situ calibration method significantly reduces sensor degradation, enhances calibration accuracy, and automates the process, allowing for extended operation without recalibration, thereby improving the operational rate and reducing downtime.
Implementation Method 1
a UV sensor 33 adapted to detect UV light emitted by the UV lamp 107
Implementation Method 2
a silicon photodiode 44 which receives the filtered light having wavelengths for measuring the illuminance and converts a signal to photoelectric current
Data Source
AI summary
A method for managing UV irradiation for treating substrates in the course of treating multiple substrates consecutively with UV light, includes: exposing a first UV sensor to the UV light at first intervals to measure illumination intensity of the UV light so as to adjust the illumination intensity to a desired level based on the measured illumination intensity; and exposing a second UV sensor to the UV light at second intervals to measure illumination intensity of the UV light so as to calibrate the first UV sensor by equalizing the illumination intensity measured by the first UV sensor substantially with the illumination intensity measured by the second UV sensor, wherein each second interval is longer than each first interval.