Heraeus Quarzglas Gmbh & Co Kg

Stefan Hengster

Martin Trommer

Walter Lehmann

Michael Hünermann

Jan Vydra

Andreas Langner

Stephan Thomas

Klaus Becker

Michael Huenermann

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

Method for homogenizing glass

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. To enable a radial mixing within the shear zone in addition to the tangential mixing with the lowest possible time and energy input, starting from this method, cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being temporarily non-coaxial with each other.

A known method for homogenizing glass includes the following steps: providing a cylindrical blank composed of the glass, having a cylindrical outer surface which extends between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and moving the shear zone along the longitudinal axis of the blank. To reduce the risk of cracks and fractures during homogenizing, it is proposed that a thermal radiation dissipator is used that at least partially surrounds the shear zone, the lateral dimension of which in the direction of the longitudinal axis of the blank is greater than the shear zone and smaller than the length of the blank, the thermal radiation dissipator being moved synchronously with the shear zone along the longitudinal axis of the blank.

Method and device for homogenizing glass

To produce a meniscus lens from synthetic quartz glass for use in a microlithography apparatus, which lens has a first optical surface () and a second optical surface () with the same direction of curvature as the first optical surface (), SiO2 particles are formed by oxidation or flame hydrolysis of a silicon-containing starting compound and deposited layer by layer on a substrate to form a cylindrical SiO2 blank which contains layers with a surface normal extending in the direction of growth. To allow such layers, which have however the least possible adverse effect on optical or mechanical properties, it is proposed according to the invention that the blank is plastically worked in a hot forming process under the effect of a deforming force to form a preform (), which has at least the first curved surface () and in which the layers are curved in the direction of curvature, and that the meniscus lens is obtained from the preform.

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Schaafheim, Germany

Stefan Hengster