Curved Mirror Laser Liquid Level Detection for Molten Silicon
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid level detection methods for melted silicon in single crystal furnaces suffer from low resolution and accuracy due to the small distance between the laser incident point and photodetector, and the large vertical distance between the laser incident plane and the liquid surface, resulting in insufficient magnification of slight changes in the liquid level.
Innovation Solution
A device and method utilizing a curved mirror with a concave reflective surface, integrated with a CCD detecting device and signal processing units, to linearly magnify the displacement of the laser spot on the sensor, allowing for improved detection accuracy by mapping the laser path and calculating a polynomial curve function for the mirror's surface to enhance the detection range and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat mirror is used to change the light path, then the device structure is simple, but the liquid level change cannot be magnified resulting in low detection accuracy
Solution Approach 1:
The patent replaces the flat mirror with a curved mirror (specifically a concave mirror) to change the light path. The curvature of the mirror surface provides magnification of the liquid level changes, transforming the small displacement of the laser spot into a larger displacement on the detector, thereby improving detection accuracy while maintaining structural simplicity.
2Measurement precision
If a cylindrical mirror is used to magnify the liquid level change, then the detection sensitivity is improved, but the magnification is nonlinear making the spot position unable to directly reflect the liquid surface position
Solution Approach 1:
The patent changes the mirror shape parameter from cylindrical to a specific curved surface (concave mirror with particular radius of curvature). This parameter change ensures that the magnification is linear, allowing the spot position on the detector to directly and linearly reflect the liquid surface position, simplifying the relationship between measured quantity and physical quantity.
3Adaptability or versatility
If the distance between laser incident point and photodetector is small, then the device fits the furnace structure, but the displacement change on sensor is small resulting in low resolution
Solution Approach 1:
The patent introduces a curved mirror as an intermediary optical element between the laser incident point and the photodetector. This intermediary component magnifies the small displacement caused by liquid level changes, converting it into a larger displacement on the detector, thereby improving detection resolution without requiring a larger distance between the incident point and detector.
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 solution enables real-time detection of the liquid surface with high accuracy, facilitating easy installation and operation, and providing linear magnification of slight changes in the liquid level, thus improving detection precision and reducing failure rates.
Implementation Method 1
a curved mirror having a concave reflective surface disposed within the detecting device housing, wherein the reflective surface of the curved mirror is disposed obliquely, the reflective surface faces the optical filter and the CCD sensor
Data Source
AI summary
A laser liquid level detection device is provided with linear optical magnification of a curved minor. The device includes a laser device, a CCD detecting device having a curved mirror and a CCD sensor and signal processing devices disposed in the laser device and the CCD detecting device. The laser device emits a laser beam to a surface level of a liquid, which reflects the beam to the CCD detecting device, and the curved mirror directs the reflected beam onto the CCD sensor. The shape of the curved mirror is determined by a polynomial curve function so as to linearly magnify a change in a height of the surface when the bounced beam reaches the CCD sensor. The liquid level detection device enables the position of the surface level of the liquid to be detectable in real time with high accuracy.