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US 8,137,469 B2Granted
Method and apparatus for making fused silica
AssigneeCorning Incorporated
InventorsDaniel Warren Hawtof, Michael T Kelley, John Stephen Rosettie, Andrew Paul Schermerhorn, Kashyap H Shah, John Stone, III, Pushkar Tandon
Life of this patent
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Abstract
Disclosed are process and apparatus for making high purity fused silica glass materials. The process involves depositing soot particles onto an essentially planar deposition supporting surface and modulation of motion of the soot-generating device relative to the deposition supporting surface to result in a low local soot density variation. The apparatus is designed to implement the planar deposition process. The invention makes it possible to produce fused silica glass without the use of potentially contaminating refractory bricks.
Claims59
A process for making doped or undoped silica glass material, comprising the following steps:
- (I) providing at least one stream of glass soot particles comprising silica via a soot-generating device;
- and
- (II) directing the at least one stream of glass soot particles to an essentially planar deposition supporting surface of a deposition substrate rotatable about a rotation axis, such that at least one layer of glass soot is deposited on the deposition supporting surface to form a soot preform, said layer having an area A1 and a thickness T1;
- wherein in step (II), the deposition supporting surface has an essentially uniform temperature such that the temperature of the deposition support surface is within ±25° C. of an average temperature and wherein the deposition supporting surface is heated to a temperature of between 500° C. and 1000° C. by an active heating source adjacent to a side of the substrate opposite the deposition supporting surface and having controllable heating power, wherein the active heating source is a planar susceptor of an induction heating system and has a surface that forms a flat plane free of an opening or aperture and is adjacent to the side of the deposition support surface, wherein a layer of refractory felt is disposed between the substrate and the active heating component, and wherein the soot-generating device is allowed to move relative to the deposition supporting surface, and the velocity of the soot-generating device relative to the deposition supporting surface is modulated such that in at least half of the area of the layer of glass soot deposited and through at least the center half thickness, local soot density variation is low.
1 more element
A process for making doped or undoped silica glass material, comprising the following steps:
- (I) providing at least one stream of glass soot particles comprising silica via a soot-generating device;
- and
- (II) directing the at least one stream of glass soot particles to an essentially planar deposition supporting surface of a deposition substrate rotatable about a rotation axis, such that at least one layer of glass soot is deposited on the deposition supporting surface to form a soot preform, said layer comprising a cylinder having a diameter of at least 5 cm and a height of at least 5 mm;
- wherein in step (II), the deposition supporting surface has an essentially uniform temperature such that the temperature of the deposition support surface is within ±25° C. of an average temperature of between about 500-1000° C., and wherein the deposition supporting surface is heated by an active heating source located adjacent to a side of the deposition substrate opposite the deposition supporting surface and having controllable heating power, wherein a layer of refractory felt is disposed between the substrate and the active heating component, and wherein the active heating source is a planar susceptor of an induction heating system and has a surface that forms a flat plane free of an opening or aperture and is adjacent to the side of the deposition support surface, and wherein the soot-generating device is allowed to move relative to the deposition supporting surface, and the velocity of the soot-generating device relative to the deposition supporting surface is modulated such that in the identified cylinder, local soot density variation measured in a plane parallel to the bottom surface of the cylinder is low.
1 more element
An apparatus for making silica glass material from glass soot particles, comprising the following components:
- (A) a soot deposition substrate having an essentially planar deposition supporting surface on which soot particles are to be deposited and capable of rotating about a rotation axis;
- (B) an active heating source located adjacent to a side of the substrate opposite the deposition support surface and having controllable heating power for heating the soot deposition substrate such that the deposition supporting surface has an essentially uniform temperature, further comprising a layer of refractory felt disposed between the substrate and the active heating component, wherein the temperature of the deposition support surface at different locations is within ±25° C. of an average temperature of between about 500-1000° C., wherein the active heating source is a planar susceptor of an induction heating system, and wherein the active heating source has a surface that forms a flat plane free of an opening or aperture and is adjacent to the side of the deposition support surface;
- (C) a glass soot-generating device located adjacent to the deposition support surface of the substrate, wherein the glass soot-generating device is (i) capable of providing at least one stream of glass soot particles and directing the stream of glass soot particles to the deposition supporting surface of the soot deposition substrate and (ii) movable horizontally and/or vertically relative to the deposition supporting surface of the soot deposition substrate;
- and
- (D) a system for controlling and driving the motion of the soot-generating device relative to the deposition supporting surface of the soot deposition substrate.
2 more elements
Dependencies are inferred from the claim text.