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Characteristics of the Electrodes of T5 Fluorescent Lamps and Development of a Lamp Life Model

Project Team at Lighting Laboratory
Project Objectives

The objectives of the research are to study the temperature and the parameters affecting on the  loss of the emissive coating of the electrodes of T5-lamps and to develop a model for the prediction of the lamp life. The main reason of a fluorescent lamp failure is the deterioration of the lamp electrodes to a level, where they are no longer electron-emissive. The hypothesis is that there is an optimum temperature for the electrode on which the loss of the emissive coating is as small as possible.

The electrode and the loss of the emissive coating is studied with infra-red camera, microscope and electrical measurements. The loss of emissive coating and the temperature of the electrode is controlled by adjusting the heating current through the electrode when lamps are dimmed. Some of the lamps are special lamps, made especially for this study, in these there are no fluorescent powder in the end of the lamp near the electrode.

Lamp life is studied with a lamp life test. According to results of the measurements and lamp life test, the lamp life is predicted. Model describes how the lamp life is affected by the different parameters.

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