Method of making glass clad glass lenses

Claim 1

THE METHOD OF MAKING A GLASS CLAD OPHTHALMIC LENS COMPRISING THE STEPS OF: FORMING A FIRST THICK LAYER OF GLASS OF THE TYPE DESIRED OF THE MAJOR PORTION OF SAID LENS, SAID GLASS HAVING A PREDETERMINED INDEX OF REFRACTION AND COEFFICIENT OF EXPANSION AND SAID LAYER BEING OF AT LEAST THE LENGTH, WIDTH AND THICKNESS DESIRED OF SAID LENS, COVERING AT LEAST ON SIDE OF SAID FIRST LAYER OF GLASS WITH A SECOND RELATIVELY THIN LAYER OF A SECOND GLASS HAVING AN APPRECIABLY LOWER COEFFICIENT OF EXPANSION THAN THAT OF SAID FIRST LAYER GLASS, COVERING SAID SECOND LAYER OF GLASS WITH A THIRD LAYER OF A REMOVABLE PROTECTIVE GLASS, FUSING WITH THE APPLICATION OF HEAT AND FIRST, SECOND AND THIRD LAYERS OF GLASS INTERFACIALLY TO ONE ANOTHER AT ONE STAGE OF THE FORMATION OF THE COMBINATION THEREOF, SAID HEAT PLACING SAID FIRST LAYER OF GLASS IN TENSION AND SAID SECOND LAYER GLASS OF LOWER COEFFICIENT OF EXPANSION IN COMPRESSION, THE FUSED COMBINATION COMPRISING A PREFORM OF SAID LENS, FLATTENING SAID PREFORM TO A DEGREE OF PRECISION PRODUCING A FINISH OF OPHTHALMIC QUALITY UPON SAID SECOND LAYER OF GLASS ADJACENT SAID THIRD LAYER, SHAPING AT LEAST A PORTION OF SAID PREFORM TO AT LEAST APPROXIMATELY THE SHAPE DESIRED OF SAID LENS, AND REMOVING SAID THIRD LAYER OF PROTECTIVE GLASS FROM SAID SHAPED PORTION OF SAID PREFORM TO EXPOSE THE UNDERLYING SURFACE OF SAID SECOND LAYER OF GLASS, SAID UNDERLYING SURFACE THUS CONSTITUTING A FINISHED SURFACE OF SAID LENS WITH SAID SECOND LAYER OF GLASS BEING IN COMPRESSION AND SAID FIRST LAYER OF GLASS UNDER TENSION WHEREBY SAID RESULTING LENS IS RENDERED HIGHLY RESISTANT TO DAMAGE BY IMPACT.

Claim 2

THE METHOD OF MAKING A GLASS CLAD OPHTHALMIC LENS COMPRISING THE STEPS OF: FORMING A FIRST THICK LAYER OF GLASS OF THE TYPE DESIRED OF THE MAJOR PORTION OF SAID LENS, SAID GLASS HAVING A PREDETERMINED INDEX OF REFRACTION AND COEFFICIENT OF EXPANSION AND SAID LAYER BEING OF AT LEAST THE LENGTH, WIDTH AND THICKNESS DESIRED OF SAID LENS, COVERING AT LEAST ON SIDE OF SAID FIRST LAYER OF GLASS WITH A SECOND RELATIVELY THIN LAYER OF A SECOND GLASS HAVING AN APPRECIABLY LOWER COEFFICIENT OF EXPANSION THAN THAT OF SAID FIRST LAYER GLASS, COVERING SAID SECOND LAYER OF GLASS WITH A THIRD LAYER OF A REMOVABLE PROTECTIVE GLASS, FUSING WITH THE APPLICATION OF HEAT AND FIRST, SECOND AND THIRD LAYERS OF GLASS INTERFACIALLY TO ONE ANOTHER AT ONE STAGE OF THE FORMATION OF THE COMBINATION THEREOF, SAID HEAT PLACING SAID FIRST LAYER OF GLASS IN TENSION AND SAID SECOND LAYER GLASS OF LOWER COEFFICIENT OF EXPANSION IN COMPRESSION, THE FUSED COMBINATION COMPRISING A PREFORM OF SAID LENS, FLATTENING SAID PREFORM TO A DEGREE OF PRECISION PRODUCING A FINISH OF OPHTHALMIC QUALITY UPON SAID SECOND LAYER OF GLASS ADJACENT SAID THIRD LAYER, SHAPING AT LEAST A PORTION OF SAID PREFORM TO AT LEAST APPROXIMATELY THE SHAPE DESIRED OF SAID LENS, AND REMOVING SAID THIRD LAYER OF PROTECTIVE GLASS FROM SAID SHAPED PORTION OF SAID PREFORM TO EXPOSE THE UNDERLYING SURFACE OF SAID SECOND LAYER OF GLASS, SAID UNDERLYING SURFACE THUS CONSTITUTING A FINISHED SURFACE OF SAID LENS WITH SAID SECOND LAYER OF GLASS BEING IN COMPRESSION AND SAID FIRST LAYER OF GLASS UNDER TENSION WHEREBY SAID RESULTING LENS IS RENDERED HIGHLY RESISTANT TO DAMAGE BY IMPACT.