Mold assembly for optical lens

Claim 1

A MOULD ASSEMBLY FOR USE IN HOT PRESSING A POWDERED COMPOUND TO FORM A SOLID, POLYCRYSTALLINE OPTICAL ELEMENT, COMPRISING A PAIR OF OPPOSED ANVIL BLOCKS, AND A POWDER CONTAINER OF METAL LOCATED FOR COMPRESSION BETWEEN THE BLOCKS AND INCLUDING A ONE-PIECE METAL RING AND A METAL CLOSURE ENGAGING ONE END OF THE RING AND SPACED FROM THE ANVIL BLOCK AT THE OTHR END OF THE RING SO AS TO BE BODILY MOVABLE TOWARDS SAID ANVIL BLOCK, THE RING AND CLOSURE BEING COMPOSED OF METAL WHICH UNDER HOT PRESSING CONDITIONS IS CAPABLE OF PLASTIC DEFORMATION WHEREBY DURING HOT PRESSING OF THE MASS OF POWDER PACKED INTO THE METAL CONTAINER THE CLOSURE BEDS SEALINGLY AGAINST THE RING END SO THAT THE PACKED POWDER IS SEALED WITHIN THE METAL CONTAINER THROUGHOUT THE COMPRESSION OF THE MASS OF POWDER, AND IN THE EVENT OF VARIATIONS IN DENSITY THROUGHOUT THE PACKED MASS OF POWDER THE METAL CONTAINER DEFORMS IN ACCORDANCE WITH SAID VARIATIONS, WITHOUT LOSS OF SEAL, TO ENSURE SUBSTANTIALLY UNIFORM DISTRIBUTION OF PRESSURE THROUGHOUT THE MASS OF POWDER.