Optical Sensor Window Cleaning With Atomized Fluid
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Solution Overview
Problem
Optical sensors face challenges in maintaining accurate measurements due to the deposition of fluid components on the optical window, which affects light transmission and leads to erroneous readings, particularly in high-accuracy applications like semiconductor manufacturing.
Innovation Solution
A sensor system with a nozzle that discharges an atomized fluid containing a liquid and gas to impact the optical window, removing deposited material through cavitation and shear force, thereby maintaining window cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to measure fluid properties, then measurement capability is provided, but deposition of fluid components on the optical window occurs which degrades measurement accuracy
Solution Approach 1:
The patent applies preliminary action by implementing a cleaning system that proactively removes deposits from the optical window before they can significantly degrade measurement accuracy. The cleaning mechanism is integrated into the sensor system and operates periodically or continuously to maintain the optical window surface, preventing the accumulation of fluid components that would otherwise scatter light and cause erroneous readings.
Solution Approach 2:
The patent implements self-service by designing an autonomous cleaning system that is integrated into the sensor assembly itself. The cleaning mechanism, which may include ultrasonic vibration, pneumatic blasting, or liquid flow, is self-contained and does not require external intervention or disassembly of the sensor. This allows the optical window to clean itself during operation, maintaining measurement accuracy without manual intervention.
2Object-affected harmful factors
If cleaning mechanisms are added to remove deposited material, then optical window cleanliness is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by integrating the cleaning mechanism directly into the sensor assembly, combining the measurement function and cleaning function into a single unified structure. The cleaning components (such as ultrasonic transducers, pneumatic nozzles, or liquid delivery systems) are embedded within or adjacent to the optical window housing, allowing both sensing and cleaning operations to occur through a single integrated unit rather than separate systems.
Solution Approach 2:
The patent utilizes pneumatic and hydraulic principles by employing gas or liquid flow to remove deposited material from the optical window. A pneumatic blast system directs high-velocity gas through nozzles onto the optical window surface to dislodge deposits, while a hydraulic cleaning system uses liquid flow to wash away contaminants. These fluid-based cleaning mechanisms are relatively simple to implement and integrate into the sensor assembly without requiring complex mechanical moving parts.
3Object-affected harmful factors
If strong cleaning forces are applied to remove all deposits, then cleaning effectiveness is improved, but risk of damaging the optical window increases
Solution Approach 1:
The patent applies mechanical vibration by using ultrasonic frequency vibrations to remove deposited material from the optical window surface. Ultrasonic transducers generate high-frequency mechanical vibrations that create cavitation bubbles and intense shear forces at the deposit-interface, effectively loosening and removing contaminants. The vibration frequency and amplitude are controlled to be sufficient for cleaning while remaining below the threshold that would cause structural damage to the optical window substrate.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the cleaning intensity parameters (such as gas pressure, liquid flow rate, ultrasonic power, or vibration amplitude) based on the level of contamination detected. The system may monitor measurement quality or deposit accumulation and modulate the cleaning force accordingly, applying stronger cleaning only when necessary and using gentler modes during normal operation to preserve the optical window while still maintaining cleanliness.
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
Effectively removes most to all deposited material from the optical window, ensuring accurate optical property measurements by preventing reattachment of debris and enhancing sensor performance.
Implementation Method 1
The light can be refracted at the boundary between the window and the fluid. Optical sensors can determine a refractive index of the fluid by detecting an amount, an angle, or an amount and an angle of the light refracted by the fluid.
Implementation Method 2
removing deposited material through cavitation and shear force
Implementation Method 3
removing deposited material through cavitation and shear force
Data Source
AI summary
A sensor assembly includes a passageway for a process fluid, an optical window, an optical sensor, and a nozzle. The optical sensor configured to detect an optical property of the process fluid. The optical window includes an inner surface. The nozzle configured discharge an atomized fluid in a discharge direction that intersects the inner surface of the optical window. A sensor system includes a sensor assembly and conduits for supplying a gas and a liquid to a nozzle of the sensor assembly. A method of cleaning an optical window in a sensor assembly includes forming an atomized fluid and discharging the atomized fluid in a discharge direction that intersects the optical window.