Device for non-contact measurement of junction temperature of white LED by use of peak wavelength displacement method

Abstract

The invention discloses a device for fast non -contact measurement of junction temperature of white LED by use of a peak wavelength displacement method. The device includes a measurement system and a calibration system. The measurement system includes a white LED light source (1) to be measured, a spectrometer (2) used for specifically measuring blue wavelength displacement and a computer (3). The spectrometer is composed of a spherical mirror (10), an entrance slit (11), a plane grating (12), an exit slit (13), a CCD (14) and a drive circuit (15). The measurement system is characterized in that a measuring wavelength range is from 440nm to 480nm and the accuracy is better than 0.02nm. The calibration system comprises a temperature controller (4), a thermostat (5), a calibration LED (6), an LED lamp holder (7), a pulsed current source (8), a spectrometer (2) and a computer (3). Through calibration of a peak wavelength-junction temperature coefficient K of the high-power white LED, displacement amount of the peak wavelength when the LED actually works is measured, and the junction temperature under working conditions of the white LED light source to be measured is thus obtained with an accuracy of the junction temperature up to 0.1 DEG C.

Description

technical field [0001] The invention relates to a detection technology of a semiconductor light-emitting diode (LED), in particular to an instrument for measuring the inner junction temperature of an LED chip. Background technique [0002] The emergence of high-brightness LED has epoch-making significance. It will be one of the greatest inventions of human beings after Edison invented the incandescent light bulb. It is called the fourth-generation lighting source or green light source. Compared with traditional light sources, it has many advantages: Light High efficiency, mercury-free environmental protection, long life, small size, etc., have been widely used in various special lighting fields such as indications, displays, decorations, backlights, and urban night scenes. At present, the luminous rate of LED can only reach 10%-30%, and at the same time, 70%-90% of the energy is converted into heat energy. The improvement of optical performance and reliability of high-perfo...

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Problems solved by technology

However, due to the increase in junction temperature, the peak wavelength drift is not large. When the temperature rises by 10°C, the peak wavelength will change by about 1.4nm, which will definitely bring a lot of error to the test results. If a conventional high-precision spectrometer is used , it will greatly increase the test cost

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