Особливості електричних, світлотехнічних та експлуатаційних характеристик напівпровідникових джерел світла

Abstract

На основі аналізу та узагальнення отриманих експериментальних даних побудовано алгебраїчну математичну модель електричних та світлотехнічних параметрів напівпровідникових джерел світла. Встановлено, що світловипромінюючі діоди є єдиним з існуючих джерел світла, в яких у процесі перехідного процесу розгорання відбувається падіння як світлового потоку, так і світлової віддачі, а при діміруванні – зростання світлової віддачі.

Basing on the analysis and generalization of the obtained and published experimental data there has been constructed an algebraic mathematical model of semiconductor light sources’ electrical and lighting parameters in the form of five interrelated equations. It has been established that light emitting diodes are the only existing light sources, in which a decrease in both the luminous flux and luminous efficacy takes place during the transition process of glow, while under that of dimming – an increase of the light output. It has been proved that the dynamics of the transition process of the decrease of the luminous flux of semiconductor light sources from the moment of switching to the moment of transition into a steady state regime (with accuracy sufficient for practical purposes) is described by the difference of decreasing and increasing exponential functions of constants of time and integration of various magnitude, which make possible to evaluate the contribution of each transient thermal resistance (the base of light emitting diode-radiator, radiator- environment) to the process of the excessive heat transfer from a driver and LEDs to the environment. It has been proved, that the decrease of the luminous flux during the transition process from the moment of switching to the transition into the steady state regime within 10% range testifies the fact, that under this condition of thermal regime of a lighting product the average duration of the light emitting diode glow will be close to the nominal value claimed in the specifications and technical documentation. The 10% value excess of the luminous flux decrease indicates the light emitting diodes’ p-n junction overheating above the allowable level, at which both the luminous efficiency and average duration of glow will be lower than stated. There has been developed a method of determining an optimal value of nominal current generated on the basis of LED lighting products in terms of providing the necessary magnitude of an average duration of glow based on the investigation of dependence of the relative decrease of their luminous flux on the current from the moment of switching to the transition into the steady state regime, which make impossible to develop and produce substandard products.