Dual CCD Parallax Detection for Czochralski Melt Solidification
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Solution Overview
Problem
Conventional methods for detecting solidification and melting completion in single crystal production by the Czochralski method are inaccurate and labor-intensive, often leading to excessive crucible damage and reduced productivity due to incomplete detection of solidification and melting states.
Innovation Solution
A method using two CCD cameras to photograph the surface of the raw material melt simultaneously from different directions, analyzing parallax data to automatically detect solidification and melting completion, thereby reducing operator workload and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a visual sensor for diameter control is used to detect solidification, then the diameter of the crystal can be detected, but the solidification state throughout the crucible cannot be grasped and detection precision is insufficient
Solution Approach 1:
The patent transitions from one-dimensional diameter detection to two-dimensional surface state detection by using two CCD cameras positioned at different angles. This dimensional change enables comprehensive observation of the melt surface and solidification patterns throughout the crucible, resolving the limitation of single-point diameter measurement.
Solution Approach 2:
The patent introduces parallax data as an intermediary parameter that mediates between the visual images captured by two cameras and the solidification state detection. By analyzing the parallax (difference in position of the same point in two images), the system can detect solidification without direct contact, enabling precise and comprehensive monitoring.
2Extent of automation
If image processing with binarization is used to detect melting completion, then automated detection is achieved, but detection accuracy is insufficient leading to delayed discovery of melting completion
Solution Approach 1:
The patent implements a feedback mechanism where the detection system continuously monitors the melt surface and provides real-time information on solidification and melting completion. The system adjusts heating power and processing timing based on this feedback, enabling precise and automated control of the melting process.
Solution Approach 2:
The patent replaces manual visual inspection with an automated optical detection system using two CCD cameras. This substitution of mechanical/manual observation with optical automation enables continuous, precise, and objective monitoring of melting completion, eliminating the delays and subjectivity of manual checks.
3Ease of operation
If visual observation by operator is used to detect solidification and melting completion, then flexibility is maintained, but operator workload increases and productivity decreases
Solution Approach 1:
The patent implements self-service detection where the system automatically monitors and detects solidification and melting completion without requiring operator intervention. The dual-CCD camera system continuously captures images, processes parallax data, and provides automatic alerts, enabling the system to monitor itself and eliminate the need for manual checking.
Solution Approach 2:
The patent ensures continuous monitoring of the melt surface through uninterrupted image capture by two CCD cameras. This continuous action eliminates the intermittent nature of manual checks, maintaining constant surveillance of solidification and melting states, thereby improving productivity while keeping operations simple and flexible.
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 allows for precise and automatic detection of solidification and melting completion, preventing crucible damage and enhancing single crystal productivity by simplifying the detection process and reducing operator reliance on visual checks.
Implementation Method 1
photographing a predetermined same test region of the surface of the raw material melt in the quartz crucible simultaneously in different directions with two CCD cameras to obtain measurement images of the test region
Implementation Method 2
a raw material contained in the quartz crucible is melted with a heater
Data Source
AI summary
A method for detecting a surface state of a raw material melt in a crucible in single crystal production by a CZ method in which a single crystal is pulled from the raw material melt in the crucible including: photographing a predetermined same test region of the surface of the raw material melt in the crucible simultaneously in different directions with two CCD cameras to obtain measurement images; and automatically detecting, using parallax data of the measurement images from the two CCD cameras, one or more of the following: solidification timing when a state in which the raw material is completely melted becomes a state in which solidification is formed on the surface of the raw material melt; and melting complication timing when a state in which the raw material melt has solidification on the surface of the raw material melt becomes a completely melted state.