Floating sheet measurement apparatus and method
View Patent ↗A sheet measurement apparatus has a sheet disposed in a melt. The measurement system uses a beam to determine a dimension of the sheet. This dimension may be, for example, height or width. The beam may be, for example, collimated light, a laser, x-rays, or gamma rays. The production of the sheet may be altered based on the measurements.
1. A sheet measurement apparatus comprising:
a melt of a material;
a sheet of said material that floats on a surface of said melt;
a pump configured to cause said melt to flow;
a cooling plate configured to use radiation cooling disposed a distance from said sheet; and
a measurement system that uses a beam to determine a dimension of said sheet.
2. The sheet measurement apparatus of claim 1 , wherein said beam is selected from the group consisting of collimated light, a laser, and x-rays.
3. The sheet measurement apparatus of claim 1 , wherein said beam is a gamma ray.
4. The sheet measurement apparatus of claim 1 , wherein said dimension is selected from the group consisting of height and width.
5. The sheet measurement apparatus of claim 1 , wherein said measurement system comprises a plurality of measurement units.
6. The sheet measurement apparatus of claim 1 , wherein said measurement system comprises at least one measurement unit, said measurement unit configured to determine a height of said sheet above a surface of said melt.
7. The sheet measurement apparatus of claim 6 , further comprising a control system, said control system configured to calculate a total height of said sheet based on said height of said sheet above said surface of said melt, a density of said sheet, and a density of said melt.
8. The sheet measurement apparatus of claim 1 , wherein said material comprises silicon or silicon and germanium.
9. A sheet measurement method comprising:
freezing a sheet of a material in a melt of said material by radiation cooling;
transporting said sheet floating on a surface of said melt wherein said sheet and said melt flow at approximately an equal speed; and
measuring a width of said sheet across said melt using a beam.
10. The sheet measurement method of claim 9 , wherein said beam is selected from the group consisting of collimated light, a laser, and x-rays.
11. The sheet measurement method of claim 9 , wherein said beam is a gamma ray.
12. The sheet measurement method of claim 9 , wherein said dimension width of said sheet is measured over time.
13. The sheet measurement method of claim 9 , wherein said measuring determines a gowth rate of said sheet.
14. The sheet measurement method of claim 9 , further comprising monitoring a consistency of said width over time.
15. The sheet measurement method of claim 9 , further comprising adjusting a parameter of said freezing or said transporting based on said measuring.
16. The sheet measurement method of claim 9 , further comprising adjusting a parameter of said freezing or said transporting using a feedback loop.
17. A sheet measurement method comprising:
flowing a melt of a material through a channel;
cooling said melt by radiation cooling;
forming a sheet of said material that floats on a surface of said melt;
flowing said sheet and said melt;
measuring a height of said sheet above said surface of said melt using a beam with a first intensity, wherein a first portion of said beam is completely blocked by said sheet and a second portion of said beam not blocked by said sheet is used for said measuring, wherein said second portion has said first intensity and is projected above a surface of said sheet; and
separating said sheet from said melt.
18. The sheet measurement method of claim 17 , further comprising calculating a total height of said sheet based on said height of said sheet above said surface of said melt, a density of said sheet, and a density of said melt.
19. The sheet measurement method of claim 17 , wherein said height of said sheet is measured over time.
20. The sheet measurement method of claim 17 , further comprising adjusting a parameter of said cooling or said flowing based on said measuring.