Low-pressure electric discharge lamp with internal elongated structure that modifiesthe diffusion length of the discharge and improves the lamp performance

Claim 1

A FLUORESCENT LAMP COMPRISING, A TUBULAR LIGHTTRANSMITTING ENVELOPE OF SUBSTANTIALLY UNIFORM DIAMETER, A QUANTITY OF MERCURY AND AN INERT IONIZABLE GASEOUS MEDIUM CONTAINED BY SAID ENVELOPE, A THERMIONIC ELECTRODE SEALED INTO EACH END OF SAID ENVELOPE, AND AN COATING ON THE INNER SURFACE OF SAID ENVELOPE, AND AN ELONGATED STRUCTURE IN AND EXTENDING LONGITUDINALLY ALONG THE DISCHARGE SPACE BETWEEN SAID ELECTRODES, SAID STRUCTURE HAVING AN ELECTRICALLY NON-CONDUCTIVE SURFACE AND BEING SO ORIENTED THAT AT LEAST A PORTION OF THE STRUCTURE EXTENDS ALONG SUBSTANTIALLY THE CENTER OF THE DISCHARGE SPACE, THE CONFIGURATION AND DIMENSIONS OF SAID STRUCTURE RELATIVE TO THOSE OF SAID ENVELOPE BEING SO CORRELATED THAT THE DISCHARGE SPACE IS OF SUBSTANTIALLY THE SAME SIZE THROUGHOUT ITS LENGTH AND SAID ENVELOPE DEFINES A SINGLE SUBSTANTIALLY UNOBSTRUCTED DISCHARGE CHAMBER, THE SURFACE AREA OF SAID STRUCTURE BEING OF SUCH MAGNITUDE THAT IT PROVIDES A NON-CONDUCTIVE RECOMBINATION SURFACE IN THE DISCHARGE SPACE THAT DECREASES THE DIFFUSION LENGTH OF THE DISCHARGE AND THUS INCREASES THE LIGHT OUTPUT OF SAID LAMP.