Catoptrical-dioptrical device for electric lighting

Claim 1

A CATOPTRICAL-DIOPTRICAL DEVICE HAVING A LAMP BULB, A SUPPORT FOR SAID BULB, AND AN ENCLOSURE FOR SAID BULB OF TRANSPARENT MATERIAL COMPRISING A SYSTEM OF STEPPED PRISMS ARRANGED IN PARALLEL PLANES TO THAT OF THE EQUATORIAL PLANE OF SAID BULB CONSISTING OF A PLURALITY OF INTERCOUPLED MOULDED PRISMS LOCATED IN CONTIGUOUS ZONES TO SAID EQUATORIAL PLANE, THE INNER SECTIONAL SURFACES OF SAID PRISMS ON WHICH THE LUMINOUS RAYS FROM SAID BULB FALL HAVING A STRAIGHT GENERATRIX AND BEING ESSENTIALLY PARALLEL TO THE VERTICAL AXIS OF SAID BULB, THE OUTER UPPER SURFACES OF SAID PRISMS FROM WHICH THE LUMINOUS RAYS ARE TOTALLY REFLECTED BEING FLAT AND INCLINED TO THE VERTICAL, AND THE OUTER LOWER SURFACES OF SAID PRISMS BEING OF CONVEX FORMATION, SO THAT THE RAYS REFLECTED FROM SAID UPPER SURFACES EMERGE FROM SAID LOWER SURFACES TO CROSS ONE ANOTHER AND DEVIATE FROM THE LONGITUDINAL AXIS OF SAID BULB WITHOUT INCIDENCE ON SAID PRISMS LOCATED ON A LOWER PLANE, THE LOWEST PART OF SAID ENCLOSURE FORMING AN ANNULAR BODY OF SUBSTANTIALLY CONCAVE FORM COMPRISING TWO SUPERIMPOSED ZONES, THE UPPER ZONE OF SAID ZONES BEING A SINGLE PRISM WHOSE INNER SECTIONAL SURFACE CONSTITUTES A SURFACE RECORDING A STRAIGHT GENERATRIX INCLINED TO THE VERTICAL AND WHOSE OUTER UPPER SURFACE IS STRAIGHT AND INCLINED TO THE VERTICAL, AND THE OUTER LOWER SURFACE OF SAID SINGLE PRISM FOLLOWS A PARTIALLY STRAIGHT AND PARTIALLY CONCAVE GENERATRIX, FROM WHICH THE RAYS EMERGE TO THE EXTERIOR IN DIVERGENT DIRECTIONS, THE LOWER ZONE OF SAID ZONES HAVING A SLIGHTLY SINUOUS INNER SURFACE AND ITS OUTER SURFACE COMPRISING A GROUP OF SMALL PARALLEL AND SUCCESSIVE PRISMS THROUGH WHICH THE LUMINOUS RAYS ARE REFRACTED TO FORM A DIVERGENT BEAM.