Block Piece for Holding an Optical Workpiece, in Particular a Spectacle Lens, for Processing Thereof, and Method for Manufacturing Spectacle Lenses According to a Prescription

A method for manufacturing spectacle lenses according to a prescription, comprising the steps of:

• (i) blocking a lens blank with a blocking face on a workpiece mounting face portion of a basic body of a block piece with the aid of a blocking material, the lens blank having a second face, opposite said blocking face, and an edge between said blocking face and said second face, said basic body further comprising a clamping portion via which the workpiece blocked on said basic body can be fixed in a machine or apparatus for processing of the workpiece;
• said basic body being substantially made from one of mineral glass or a plastic material that has a water absorption of less than 1% at saturation, measured in accordance with DIN EN ISO 62:1999-08, method 1, so that the block piece is useable in thin film coating processes;
• (ii) processing the blocked lens blank on said second face and optionally said edge to obtain a processed lens while on said block piece, and
• (iii) deblocking the processed lens from said block piece.

A block piece for holding an optical workpiece for processing thereof, comprising:

• a basic body having a workpiece mounting face portion against which the workpiece can be blocked by a blocking material and a clamping portion via which the workpiece blocked on said basic body can be fixed in a machine or apparatus for processing of the workpiece;
• said clamping portion being constructed to be clamped by clamping forces that are directed essentially in one of a circumferential direction with respect to a central axis of said basic body and a tangential direction at a distance with respect to the central axis of said basic body;
• and
• said clamping portion of said basic body has at least one radially extending clamping protrusion that has two opposed side faces each facing in the circumferential direction, for application of said clamping forces.