Czochralski Crystal Pulling Apparatus Neck Support Latches
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Solution Overview
Problem
Existing crystal pulling apparatuses using the Czochralski method face challenges in supporting heavy crystals due to the neck's inability to absorb the weight, leading to structural defects and impurities from complex and prone-to-failure actuation mechanisms in support devices.
Innovation Solution
A simplified support device with swivellable latches actuated by external mechanical means, allowing them to automatically transition from a resting to an operating position without contacting the crystal, distributing the load through synchronized lifting and rotating devices to prevent neck damage and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a support device with complex actuation means (hydraulic cylinders, elastic counterbearings) is used to support heavy crystals, then the crystal weight can be distributed, but the device complexity increases and reliability decreases due to high temperature environment
Solution Approach 1:
The patent removes the complex actuation means (hydraulic cylinders, elastic counterbearings) from the support device, extracting only the essential functional elements (latches and base body) needed to support the crystal weight. This simplifies the device while maintaining the load-bearing capability.
Solution Approach 2:
The latches are designed to automatically transition between operational states based on the crystal weight and position, eliminating the need for external actuation systems. The support device serves itself by using the crystal's own weight and position to trigger the latch mechanism, rather than requiring complex external control systems.
2Device complexity
If simple fork-like latches are used that slide along the crystal enlargement during lowering, then the device complexity is reduced, but harmful factors increase due to abrasion particles and crystal vibrations
Solution Approach 1:
The latches are pre-positioned in a retracted state before the base body is lowered, ensuring they do not contact the crystal enlargement during the lowering process. This preliminary positioning prevents abrasion and particle generation before the support function is actually needed.
Solution Approach 2:
The patent introduces an intermediary mechanism (the controlled transition of latches from retracted to engaged position) that mediates between the base body movement and crystal contact. This ensures the latches only contact the crystal when necessary for support, minimizing harmful interactions.
3Manufacturing precision
If the neck is kept thin for growth technology reasons, then the crystal quality is improved, but the neck can no longer absorb the weight of large diameter crystals
Solution Approach 1:
The patent segments the load-bearing function from the growth function by introducing a separate support device that independently carries the crystal weight. This allows the neck to remain thin for quality purposes while the support device handles the mechanical load, separating these two conflicting requirements.
Solution Approach 2:
The support device acts as an intermediary between the thin neck and the heavy crystal body, transferring the load away from the neck. This mediator enables the neck to maintain its thin, quality-optimized dimensions while still supporting the overall crystal structure through the intermediate support mechanism.
Data Source
AI summary
A pulling apparatus and a method with which especially heavy crystals (5) can be pulled using the Czochralski method utilizing the pulling apparatus. For this purpose the neck (4) of the crystal (5) has an enlargement (10) beneath which extends the support device. This device includes latches (7), which are moved from a resting position into an operating position in which the latches (7) extend beneath the enlargement (10). Each latch (7) is supported on the base body such that it is swivellable about a pivot axis (8) and can assume two stable positions, namely the resting position and the operating position. Each of these positions is defined by a stop on the base body. When the latch rests on the one stop, its center of gravity, viewed from the neck (4), is located on the other side of the pivot axis (8). When the latch rests on the other stop, the center of gravity is located on this side of the pivot axis (8). The actuation of the latches (7) takes place with actuation means disposed stationarily in the apparatus.