Device and method for detecting liquid level of molten silicon using laser reflected from curved mirror

A device to detect a liquid level of molten silicon, comprising:

• a charged-coupled device (CCD) detector comprising
• a housing,
• an optical filter horizontally disposed at a bottom of the housing,
• a driving board vertically disposed at an inner wall of the housing,
• a CCD sensor vertically disposed at an inner side of the driving board,
• a curved mirror having a concave reflective surface disposed within the housing, and
• a connector disposed at a top of the housing, wherein the reflective surface of the curved mirror is disposed obliquely, and the reflective surface faces the optical filter and the CCD sensor, wherein the curved mirror is configured to bounce an input laser beam from a surface of molten silicon onto the CCD sensor so that a change in a height of the surface and a corresponding incident point on the CCD sensor have a linear relationship;
• a signal processing device disposed within the CCD detector;
• openings disposed at a top of a crystal furnace;
• gold-plated quartz glasses disposed at the openings;
• and
• a laser device and a CCD detecting device respectively disposed at the openings.