Sealed electric lamp having envelope with light diffusing and focusing characteristics

Claim 1

A LAMP STRUCTURE, COMPRISING A FILAMENT ADAPTED TO EMIT LIGHT WHEN RENDERED INCANDESCENT, A FLARING HOLLOW ONE-PIECE GLASS ENVELOPE HAVING A WIDE END AND A NARROW NECK END, SAID ENVELOPE BEING GENERALLY PARABOLIC IN SECTION, SAID FILAMENT BEING LOCATED AT THE FOCUS OF THE ENVELOPE, AN OUTWARDLY CONVEX, CIRCULAR END FACE INTEGRAL WITH THE WIDE END OF THE ENVELOPE, SAID FACE HAVING ITS OUTER SIDE FORMED WITH A PLURALITY OF SMALL CONVEX PROJECTIONS DEFINING INDIVIDUAL LENSES, SAID PROJECTIONS BEING DISPOSED IN AN ANNULAR ARRAY EXTENDING FROM THE PERIPHERY OF SAID FACE RADIALLY INWARDLY THEREOF TO A CENTRAL CLEAR FOCAL AREA OF THE FACE, A CLOSURE FOR SAID NECK FUSED THERETO, A PAIR OF CONDUCTIVE STEMS FUSED IN SAID CLOSURE AND SUPPORTING SAID FILAMENT AND EXTENDING OUTWARDLY OF THE ENVELOPE, AND MEANS CONNECTING SAID STEMS TO AN EXTERNAL POWER SUPPLY FOR ENERGIZING SAID FILAMENT, SAID CENTRAL CLEAR FOCAL AREA BEING FORMED WITH A CONVEX PORTION HAVING A RADIUS OF CURVATURE LARGER THAN THE RADIUS OF CURVATURE OF THE INDIVIDUAL SMALL LENSES, WHEREBY SAID CONVEX PORTION SERVES TO PROJECT A CONVERGING SPOT OF LIGHT CENTRALLY OF SAID END FACE, WHILE SAID SMALL LENSES DIFFUSE LIGHT PASSING THERETHROUGH.