Light Flicker-Factor as a Diagnostic Quantity for the Evaluation of Discharge Instabilities in HID Lamps

Abstract

There are some phenomena in High Intensity Discharge (HID) lamps which have the potential to make the discharge unstable. Discharge instability, can lead to some transients in light intensity or in its periodic form, to annoying light flickering. Instabilities appear in a vast range. Depending on the strength of the source of instability, it varies from a very slight deflection of sodium sheath to extreme deviations of conducting channel from its normal position which can extinguish the lamp as well. In order to detect the existence of such phenomena and predict their potential power, their effects and consequences on the light intensity can be analyzed. This has been done by using a tuned model of the human eye-brain system, to predict the perceptibility of the transient changes of light. The purpose of this paper is to introduce the ‘light flicker factor’ based on eye-brain model as a measure of discharge instabilities. The implementing method of the model and a proper measuring system for light flicker factor is being discussed. Some laboratory experiments to support this method of measurement are presented.

Keywords:

• HID lamps
• flicker
• evaluation