CPC B32B 3/263 (2013.01) [B32B 3/02 (2013.01); B32B 3/26 (2013.01); B32B 3/30 (2013.01); B32B 17/10036 (2013.01); B32B 17/10045 (2013.01); B32B 17/10119 (2013.01); B32B 17/10137 (2013.01); C03B 17/064 (2013.01); C03B 18/02 (2013.01); C03B 23/023 (2013.01); C03C 3/083 (2013.01); C03C 3/087 (2013.01); C03C 3/093 (2013.01); C03C 21/002 (2013.01); B32B 2315/08 (2013.01); B32B 2329/04 (2013.01); B32B 2329/06 (2013.01); B32B 2551/00 (2013.01); B32B 2571/00 (2013.01); B32B 2605/006 (2013.01); Y10T 428/24777 (2015.01)] | 12 Claims |
1. A method for producing a glass substrate, comprising:
melting glass components to form a glass melt;
adjusting a viscosity (η) of the glass melt upstream of a throughput control component or tweel by cooling;
adjusting a viscosity η1 of the glass melt at a distance y1 that is less than or equal to 1.5 m from a location immediately downstream of the throughput control component or tweel, by cooling and according to the following equation:
lgη1(y1)/dPa·s=(lgη01/dPa·s+a1(y1))
where η01 is a value of glass viscosity at y=0 m and lg η01 is a logarithm of the glass viscosity η1 at y=0 m,
0 m≤y1≤1.5 m being a distance of the location immediately downstream of the flow rate control component that is located at y=0 m,
3.75≤lg η01/dPa·s≤4.5 being the range of viscosities to be adjusted at y=0 m, and
a1(y1)=1.00/m*y1, being a positive change in the range of viscosities to be adjusted over 0 m≤y1≤1.5 m;
delivering the glass melt to a forming device; and
forming the glass melt to form the glass substrate by a forming process that comprises a drawing process that causes a formation of drawing streaks on a main surface of the glass substrate,
wherein the drawing streaks comprise elevations that rise in a normal direction, have a longitudinal extent that is greater than two times a transverse extent of the elevations, and have a mean height that is less than 100 nm.
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