LED lamps work on the basis of current. Electrical parameters mainly include forward voltage, reverse voltage and reverse current, which are related to whether LED lamps can work normally. It is one of the bases to judge the basic performance of LED lamps. So what are the basic performance measurement methods of LED lamps?
The thermal characteristics of LED have an important influence on the optical and electrical characteristics of LED. Thermal resistance and junction temperature are the main thermal characteristics of LED2. Thermal resistance refers to the thermal resistance between the PN junction and the shell surface, that is, the ratio of the temperature difference along the heat flow channel to the power dissipated on the channel. Junction temperature refers to the temperature of the LED PN junction.
The methods to measure the junction temperature and thermal resistance of LED are: infrared micro imager method, spectrum method, electrical parameter method, photo thermal resistance scanning method, etc. The surface temperature of LED chip measured by infrared temperature measuring microscope or micro thermocouple is not accurate enough as the junction temperature of LED.
At present, the commonly used electric parameter method is to use the linear relationship between the forward voltage drop of ledpn junction and the temperature of PN junction. The junction temperature of LED is obtained by measuring the forward voltage drop difference under different temperatures.