Method for measuring integral light decay property of LED (light emitting diode) lamp

Abstract

The invention discloses a method for measuring the integral light decay property of an LED (light emitting diode) lamp. The method comprises the following steps: firstly, selecting an LED lamp bead in the LED lamp as a to-be-tested device, secondly, putting the LED lamp into an incubator, disconnecting a circuit line between a driving power output and an LED array, connecting an ammeter in the circuit in series, and connecting a voltmeter to two sides of the to-be-tested device, thirdly, stabilizing the testing temperature in the incubator, taking the testing temperature as initial temperature T1, fourthly, turning on the LED lamp, and recording working voltage V1 and series current I1, fifthly, recording working voltage V2 and series current I2 at a stable thermal equilibrium state, sixthly, obtaining forward voltage difference Delta Vf, which is equal to V2 minus V1, seventhly, obtaining junction temperature difference Delta t, which is equal to Delta Vf / K, eighthly, obtaining junction temperature value T2, which is equal to T1 plus Delta t, and ninthly, looking up the light decay curve of an LED device, taking a cross axis reading in a position where a corresponding T2 decline curve and 70 percent of a normal axis are intersected as the service life of LED and also as the service life of the LED lamp at 70 percent of light decay.

Description

technical field [0001] The invention provides a method for measuring the overall light attenuation characteristics of LED lamps. Background technique [0002] LED lamps have the characteristics of low energy consumption and long life, but this needs to be based on the temperature environment in a specific area where the internal LED can work stably. In fact, the light decay factor of LED depends on its junction temperature. There are very mature methods for measuring the light attenuation characteristics of a single LED, but there is no simple, practical, fast and accurate method for measuring the overall light attenuation after the LED lamp is assembled, except for the Lm80 solution recommended by DOE. If there is no effective method to test the junction temperature of the LED inside the lamp, the lifespan can only be judged by directly measuring the natural attenuation value of the light intensity of the LED lamp over time. Although the result is credible, it is time-consu...

AI Technical Summary

Problems solved by technology

There are many and complicated factors that affect the junction temperature of LED devices. There are many ways to measure the junction temperature of LEDs in lamps with current technological means, but the results are not accurate enough.

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