a long , tubular incandescent lamp has incorporated therein a filament formed by coupling light emitting segments and non - light - emitting segments alternately with each other . each of the light emitting segments is composed of a light emitting coil and a coil - like coupling member of a larger pitch than the light emitting coil . each of the non - light - emitting segments is composed of a bar formed to have a straight short - circuit part , bent portions at both ends thereof and supports respectively extending from the bent portions . the short - circuit part is inserted into the coil - like coupling member and these elements are then welded to each other to obtain the filament of alternately coupled light emitting and non - light - emitting segments . the composite filament is subsequently sealed in a long , tubular bulb . thus , the resulting incandescent lamp is easily assembled , simple in structure , and highly shock resistant .