Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp

A forward voltage, relationship curve technology, used in lamp testing, single semiconductor device testing, etc., can solve the problem of inability to measure PN junction junction temperature, etc., to achieve practical junction temperature and thermal resistance, high measurement accuracy, and can not solve the problem. The effect of accurate measurement

Active Publication Date: 2013-10-09
SHANGHAI ALPHA LIGHTING EQUIP TESTING +3
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

However, after the LED is installed in the lamp, it is impossible to measure its PN junction temperature with the traditional contact method and thermal radiation method.

Method used

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  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp
  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp
  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp

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Experimental program
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Embodiment Construction

[0014] Put the LED matrix in the luminaire using LED (see Figure 1a ) in a series LED group in the middle of a tested LED at or near the middle, that is, the two connecting wires of LED-2 in the figure are cut off, and connected by three 2-pole 2-throw switching relays to form a Figure 1b , so that the LED under test is connected to the disconnected part or the constant current source of the above-mentioned series LED group through the three 2-pole 2-throw switching relays. When the measured LED is connected to the disconnected part of the above-mentioned series LED group, it is the working position , when the LED under test is connected to the constant current source, it is the measurement position, first adjust the three 2-pole 2-throw switching relays to the measurement position. At the heat sink of the LED (the LED comes with a small heat sink), glue a thermoelectric corner and connect the thermoelectric corner to the thermometer. Figure 1b 1 is the constant current sou...

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Abstract

The invention discloses a method for measuring a relation curve of a forward voltage and a junction temperature of an LED (Light Emitting Diode) in a lamp. In the invention, the method comprises the steps of obtaining a dropping amount of the forward voltage under a set measuring current within a unit measuring time; correcting the forward voltage drop of the measured LED by using the dropping amount of the forward voltage drop within the unit measuring time and an actual measuring time so as to improve the measuring accuracies of the forward voltage drop and the corresponding junction temperature of the measured LED; and measuring the forward voltage drop of the measured LED and figuring out the forward voltage drop of the measured LED at the moment of disconnecting the working current when the continuous working temperature of the LED lamp reaches heat balance. By using the method disclosed by the invention, the situation that the junction temperature of the measured LED obviously biases from a correct value due to the disconnection of the working current of the measured LED and fast dropping of the junction temperature of the LED can be effectively eliminated. The method disclosed by the invention has the advantages of convenience in use and high measuring accuracy; and the difficulty that the actual working junction temperature and the heat resistance of the LED in the traditional lamp cannot be accurately measured is solved.

Description

technical field [0001] The utility model relates to the field of lighting lamps, in particular to a method for measuring the relationship curve between the forward voltage of LEDs in the lamp and the junction temperature. Background technique [0002] When LEDs are used in lighting fixtures, because the service life of LEDs is generally very long, about tens of thousands of hours, it is necessary to measure the light attenuation and lifespan of lighting fixtures using LEDs. According to the LM80 requirements of the US DOE, it often takes more than 300 days. (6000h), but if two quantitative indicators, the PN junction junction temperature of the LED in the lamp and the thermal resistance from the PN junction to a specified point of the radiator, can be accurately measured, it can not only measure the advantages and disadvantages of the heat dissipation characteristics of the LED lamps and lanterns It can also qualitatively know the service life of various similar lamps that u...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/26G01R31/44
Inventor 刘尔立杨樾施晓红汪钢黄习德俞安琪强耀根陈大国
Owner SHANGHAI ALPHA LIGHTING EQUIP TESTING
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