Study fluorescent lamp with

(1)

Study on the fluorescent lamp electrode concerned with the discharge phenomena

2000

Katsuhide Misono

The present thesis is subjected to the problems on the fluorescent lamp electrode concerned with the discharge phenomena operated under high frequency lamp voltage. The aim of the present study is to improve the lifetime of the electrodes

^so

that the auxiliary electrodes hearing have been deeply investigated though the establishment of the electrode model for the numerical analysis, verified well by the experiment. As

a

result, the most appropriate condition for the electrodes temperature to make the emitter consumption minimum

has been

found

At first, a simple method to measure the plasma density and electron temperature has been developed by a search coil inductively coupled with

a

plasma. This method was applied throughout the present study.

Next, the numerical analysis presumed that the breakdown voltage of the lamp

has

remarkably

decreased

at the appropriate preheating current

because

effective 7 is largely increased due to the thermionic electron current. It was found that the light intensity emitted from barium atoms and ions at the begining of the discharge became minimum against the average electrode temperature of 700-900C. The lamp switching test

^has

confirmed that the wall blackening of the lamp was greatly reduced under the present condition. The barium emission intensity together with the temperature of the bright spot on the electrode, anode oscillation on the lamp voltage and the electron density were measured

^{as a}

function of the lamp operation frequency. It was clarified that the barium released from the electrode was due to sputtering, which was increased with the frequency of the lamp voltage increasing.

Finally, the experimental results have

been used

to consider the condition of the auxiliary electrode heating to

^suppress

the emitter consumption to a

_Ereat

Study fluorescent lamp with

Study on the fluorescent lamp electrode concerned with the discharge phenomena

2000

Katsuhide Misono

The present thesis is subjected to the problems on the fluorescent lamp electrode concerned with the discharge phenomena operated under high frequency lamp voltage. The aim of the present study is to improve the lifetime of the electrodes

that the auxiliary electrodes hearing have been deeply investigated though the establishment of the electrode model for the numerical analysis, verified well by the experiment. As

result, the most appropriate condition for the electrodes temperature to make the emitter consumption minimum

found

At first, a simple method to measure the plasma density and electron temperature has been developed by a search coil inductively coupled with

plasma. This method was applied throughout the present study.

Next, the numerical analysis presumed that the breakdown voltage of the lamp

remarkably

at the appropriate preheating current

effective 7 is largely increased due to the thermionic electron current. It was found that the light intensity emitted from barium atoms and ions at the begining of the discharge became minimum against the average electrode temperature of 700-900C. The lamp switching test

confirmed that the wall blackening of the lamp was greatly reduced under the present condition. The barium emission intensity together with the temperature of the bright spot on the electrode, anode oscillation on the lamp voltage and the electron density were measured

function of the lamp operation frequency. It was clarified that the barium released from the electrode was due to sputtering, which was increased with the frequency of the lamp voltage increasing.

Finally, the experimental results have

to consider the condition of the auxiliary electrode heating to

the emitter consumption to a

extent. The numerical analysis of the electrodes by the model qualitatively agreed with the experimental results.

The results obtained

to develop novel fluorescent lamp

for high frequency operation.

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