The present invention relates to a flexible glass element and to a stack assembly comprising the glass element. The invention also relates to a method of producing the glass element or stack assembly comprising the same.

A glass manufacturing apparatus includes a delivery apparatus defining an upstream portion of a ribbon travel path extending in a first travel direction. The glass manufacturing apparatus includes a forming roll extending along an axis parallel to the travel path and perpendicular to the first travel direction. The forming roll includes a recess that imparts a protrusion to a ribbon traveling along the ribbon travel path in the first travel direction. The forming roll includes a first surface defining the recess and a first surface characteristic. The forming roll includes a second surface defining an area surrounding the recess and including a second surface characteristic. The first surface characteristic is different than the second surface characteristic. During a cooling period of time, the first surface cools at a faster rate than the second surface. Methods of manufacturing a ribbon are provided.

A window manufacturing device may include a melting unit configured to supply molten glass and a shape processing unit disposed adjacent to the melting unit in a direction in which the molten glass is discharged from the melting unit. The window manufacturing device may include a protruding portion that forms a groove in the preliminary glass discharged from the melting unit so that glass manufacturing and shape processing can be continuously performed, thereby improving the process quality of a manufactured window and increasing process economy.