Lighting fixture and method for operating same

A luminary for fluorescent tubes, the luminary comprising:

• one or more fluorescent tubes that contain mercury vapor gas and at least one electrode located at ends of the fluorescent tubes, each of the electrodes includes heating filament cathodes;
• a fixture at each end of the tube fluorescent tubes that comprises holding and connection devices for the fluorescent tubes, each of the fixtures being configured to short cut the filament cathodes of the electrodes of the fluorescent tubes respectively, to cancel current through the electrodes, and to thus avoid the losses in voltage;
• and
• a ballast for driving the fluorescent tubes, the ballast being configured to generate voltage pulses applied to the electrodes for exciting the mercury vapor gas, the pulses consisting of non-periodic voltage levels separated by variable duration dead times being of alternative form including amplitudes of equal values but of positive and negative polarity;
• wherein the dead times are maintained as long as a resonance effect in the mercury vapor gas maintains light emission, wherein the resonance effect is determined from real time samplings of the current crossing the one or more fluorescent tubes.

A method of operating a fluorescent tube for reducing an operating temperature the fluorescent tube and improving electronic ballast reliability, said method comprising the steps of:

• providing at least one fluorescent tube containing a mercury vapor gas, at least one electrode including at least one heating filament cathode located at each end of the fluorescent tube, a fixture that comprises holding and connection devices for the fluorescent tube at each end, and a ballast for driving the fluorescent tube;
• producing non periodic voltage pulses from the ballast;
• applying the non-periodic voltage pulses to the electrodes for exciting the mercury vapor gas, the non-periodic pulses are separated by variable duration dead times being of alternative form including amplitudes of equal values but of positive and negative polarity;
• igniting conduction through the mercury vapor gas of the fluorescent tube by the temporary connection of a capacitor in parallel with the fluorescent tube making it possible to increase tension between the electrodes of the fluorescent tube;
• disconnecting the capacitor when conduction is obtained;
• controlling a pre-heating of the cathodes of the electrodes until a predetermined optimal operation is reached due to a controlled and specific excitation during the igniting conduction through the mercury vapor gas indifferent to temperature in the fluorescent tube;
• monitoring current flowing through the fluorescent tube for determining a resonance effect, thereby allowing the ballast to monitor a voltage waveform of the fluorescent tube in real time;
• regulating the dead time according to at least one programmed function that supervises the conditions and physical parameters coupling voltage variations and collision rate between electrons and mercury atoms;
• allowing the igniting conduction to continue until a predetermined nominal running mode is reached;
• allowing the current crossing the fluorescent tube and emission of light from the fluorescent tube to increase by successive steps;
• allowing the current to decrease until a phenomenon of resonance is stable according to environmental conditions, the phenomenon of resonance being a resonance effect in the mercury vapor gas that increases a number of collisions between the electrons and the mercury atoms;
• and
• increasing the number of collisions between electrons and mercury atoms by depending current intensity on the resonance effect in the mercury vapor gas.