Petrol Car LED lights refer to lamps that use LED technology for both exterior and interior lighting as light sources inside and outside the vehicle. Exterior lighting is about thermal limits and EMC. Use Petrol Car LED lights to create the interior environment of the car. The service life is 50,000 hours. The LED structure is solid and not easily affected by vibration. The light output brightness will not drop significantly during use.
Compared with traditional light sources, the physical size, luminous flux, spectrum and spatial distribution of light intensity of LED light sources are very different. Therefore, LED detection cannot copy the standards and methods of traditional light source detection. The editor is here to introduce to you the detection techniques of commonly used Petrol Car LED lights.
Electrical parameters mainly include forward voltage, reverse voltage and reverse current, which are related to whether the LED lights of Volkswagen Car can work normally and are one of the basis for judging the basic performance of LED lights of Volkswagen Car. There are two methods for measuring the electrical parameters of Petrol Car LED lights: one is to test the voltage parameters when the current is constant; when the voltage is constant, the current parameters are tested. The specific methods are as follows:
(1) DC voltage. When a forward current is applied to the LED lamp of a Petrol Car to be detected, a voltage drop will occur at both ends. Adjust the power supply determined by the current value and record the relevant reading on the DC voltmeter, which is the DC voltage of the LED light of the Petrol Car. According to common sense, when the LED is forward-conducting, the resistance is small, and it is more accurate to use an external ammeter.
(2) Reverse current. Add reverse voltage to the LED lamp of the Petrol Car under test, and after adjusting the regulated power supply, the ammeter reading is the reverse current of the LED lamp of the Petrol Car under test. As with direct voltage measurement, the LED is internally connected to an ammeter due to the higher resistance in reverse conduction.
2. Thermal characteristic test
The thermal characteristics of LEDs have an important impact on the photoelectric characteristics of LEDs. 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 surface of the housing, that is, the ratio of the temperature difference along the heat flow channel to the power dissipated on the channel. The junction temperature refers to the temperature of the LEDpn junction.
Methods for measuring LED junction temperature and thermal resistance generally include: infrared microphotography, spectroscopy, electrical parameter method, photothermal resistance scanning method, etc. Since the junction temperature of LED is not accurate enough, use an infrared temperature measurement microscope or a micro thermocouple to measure the surface temperature of the LED chip. The currently commonly used electrical parameter method is to use the linear relationship between the LED PN junction forward voltage drop and the PN junction temperature to obtain the LED junction temperature by measuring the forward voltage drop difference at different temperatures.