Fluorescent lamp with shielded electrodes

Claim 1

In a fluorescent lamp of the type comprising a sealed, elongated tubular light-conducting envelope containing an arcconducting gas, a light-emitting phosphor coating on the inside of the envelope and electron-emitting electrodes at each end of the envelope electrically connected to conductors extending through the ends of the envelope, shielding means for preventing emission outside the walls of the envelope of radiation generated in the electrode area of the lamp, said shielding means comprising: a shielding member mounted on said lamp envelope outside the path of the arc discharge between the lamp electrodes and arranged to extend around the electrode area of the lamp envelope, said shielding member being constructed of a material having a high atomic number and density, which will absorb radiation such as X-rays, said material having sufficient thickness and axial length to absorb substantially all of the radiation emanating from the electrode area of the lamp around which it extends, which radiation would otherwise pass through the lamp envelope into the area illuminated by the lamp.