Method for producing single microlenses or an array of microlenses

A method for producing single microlenses or an array of microlenses composed of a glass material, the method comprising:

• providing a first substrate with a surface containing impressions over which a second substrate composed of a glass material is placed at least partially overlapping it and is joined therewith, with a gaseous medium being enclosed in the impressions between the first and said second substrate and
• tempering the substrate composite in such a manner that the second substrate softens and is displaced by the gaseous medium expanding in the area of the impressions thereby structuring the side of the second substrate facing away from the first substrate to form at least one convex microlens surface,
• wherein the first substrate is provided having a first impression which encloses with the second substrate a first cavity with the second substrate in which the gaseous medium is enclosed which expands during tempering and displaces the softened glass material to form a convex surface contour on a microlens surface lying opposite the first substrate, and
• wherein on the first substrate at least one second impression is provided separated by an intermediate fillet next to the first impression, the at least one second impression enclosing with the second substrate a second cavity in which the gaseous medium is enclosed which expands during tempering and displaces the softened glass material to form a curvature, which can be prescribed, of the microlens surface at least in a subdomain of the convex surface contour.