Fudan University

Xiaoli Zhou

Muqing Liu

Chuan Yuan

Wenyi Li

Hai Ping Shen

Wanlu Zhang

The present invention relates to the technical field of measuring light source, specifically, to the method for measuring the luminous flux of LED. In the present invention, a reflecting cup is used as a collector of the luminous flux of LED. The collector has two sectional openings in the direction perpendicular to the symmetric axis thereof, which are positioned in the front and in the rear respectively, one of them positioned at the bottom end of the collector and having a smaller radius is used to input the light emitted by LED to be measured, the other positioned in the front end of the collector and having a larger radius is used to output the light to the detector placed in this position. Specifically, LED is fixed at the bottom end of the collector with a fixture, the light emitted by LED is directed toward the large opening of the collector, and the photometer is fixed closely at the large opening of the collector to receive light signals. LED is driven with a constant current power supply, and the total luminous flux emitted by LED is concentrated by the collector, collected and measured by the detector, then corrected by using a calibrating coefficient, in order to achieve the numerical readings of the value of the total luminous flux. The method of the present invention is simple and has a high measuring accuracy.

Method using concentrator for measuring luminous flux of LED

This invention belongs to the luminous flux measurement field, and especially relates to the equipment and method for LED's total luminous flux measurement with a narrow beam standard light source. The system for LED's total luminous flux measurement with a narrow beam standard light source in this invention comprises an integrating sphere, the light source, a narrow aperture fiber, a spectrometer and a driver for the light source. The light source is lighted by the driver. The narrow beam standard light source (both luminous flux standard and spectrum standard) is placed on the interior surface of integrating sphere, there is not any baffle in the sphere, and a narrow aperture fiber transfers the light to a multi-channel spectrometer which measures the spectrum distribution of LED and calculates its total luminous flux. The equipment in this invention is easy to use, has small error and low cost, and can achieve accurate results for LED's total luminous flux.

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Shanghai, China

Xiaoli Zhou