LAMPE ELECTRIQUE PRESENTANT UN RAPPORT DETERMINE ELEVE DES EPAISSEURS DE L'AMPOULE EXTERIEURE ET DE L'AMPOULE INTERIEURE

An electric lamp having a relatively high outer-envelope to inner-envelope wall-thickness ratio whereby the risk of a containment failure of the lamp is substantially eliminated. In an alternate embodiment, the outer envelope has a concave top. In another embodiment, the neck of the outer envelope has a relatively thick wall. Lamps having a wall-thickness ratio falling within the prescribed range, i.e., approximately equal to or greater than 3, have the property that the outer envelope will contain shards of the inner light-source capsule in the unlikely event such inner capsule should burst.