Based on the LM-79 standard, how to use the integrating spheres and spectrophotometers to test the LED luminaire

The electro-optical test methods allowed by IESNA Solid State Lighting Products, specifically referred to as LM-79, are jointly developed by IESN and the ANSI Solid State Lighting Committee, and the main contents include:

1.  Cover luminaires including light sources and light sources used as luminaires (such as LED update products)

2. The optical test method adopts the relative measurement method of the integrating sphere, the absolute measurement method of the spectrophotometer and the spectroscopic radiation test method

The main function of the integrating sphere in the light source test process is to be used as a light collector, which is an important component of the photometric measurement system. The integrating sphere is a hollow sphere, the shell is generally made of sheet metal shard welding or integral rotary pressing, and the inner wall is sprayed with reflective paint. According to the different photometric equipment, the integrating sphere measurement system is divided into two categories: integrating sphere photometer measurement system and integrating sphere spectral analysis system. The former uses a photometric probe as a detector, and cooperates with a photometer to measure light parameters; The latter uses optical fibers to collect the light from the wall of the ball and uses a spectrometer to measure parameters such as luminosity, color, and radioactivity.

The spectrophotometer is the main measuring device for the light distribution performance test of lamps and lanterns, which can be used to measure the spatial luminous intensity, distributed total luminous flux and luminaire efficiency of lamps or light sources. The composition of the meter system includes: precision turntable and control system, spectral analysis system, standard lamp, alignment system, computer processing system and other parts.
Distributed luminosity of parameters such as total luminous flux and luminaire efficiency. The composition of the meter system includes: precision turntable and control system, spectral analysis system, standard lamp, alignment system, computer processing system and other parts.

3. Optical information tests include: total luminous flux (lumens), luminous brightness (Canterra) ( one direction or multiple directions), chromaticity coordinates, color temperature ( CCT), and color rendering index ( CRI)

Here we take the luminous flux (lumens) as an example, one is the integration method using an integrating sphere plus photometer or spectral radiometer test

This is the total luminous flux relative measurement method; the principle of integral method to test the total luminous flux is calibrated by the luminous flux standard. Since it is calibrated with a standard lamp, it is not necessary to know the spectral output of the sphere, and the luminous flux of the LED lamp product under test is calculated compared with the standard lamp. Generally speaking, the integration method is suitable for small integrated LED lamps and relatively small LED light sources to test the total luminous flux and color parameters, which is the relative test method of the total luminous flux, the integration method has the advantages of fast measurement speed and no anechoic chamber, usually the smaller the volume, the closer to the point light source The more accurate the lamp test results.

The other is the photometric method using a distributed photometer

This is an absolute measure of total luminous flux. The use of photometric test total luminous flux is the use of distributed luminous timing, its total luminous flux test limitations are very small, photometric test total luminous flux principle is distributed photometer in many different directions of the light source to measure the light source or in a given distance of the light source illuminance of the light intensity of the equipment, through the light intensity data in each direction to calculate the total luminous flux.

The measurement principles of integrating spheres and distributed photometers are different in terms of environment and test method, and the measurement results of the two are not comparable. We can choose the right way to test according to different standards and different requirements.

4. Electrical information test includes: current, voltage, power

5. The product must be stable and achieve thermal equilibrium before testing

As mentioned above, for the content of the LM-79 standard, LISUN GROUP launched the best-selling models

LPCE-3 series LED spectrometer integrating sphere integrated system, specialized in measuring instruments for photometric parameters, chromaticity parameters and electrical parameters of single LED and LED luminaires. The measured data complied with the measurement requirements in CIE177, CIE-13.3, CIE-84, ANSI-C78.377, (EU) 2019/2015, GB/T24824, IESNA-LM-63-2, Optical-Engineering-49-3-033602, LM-80 and LM-79.

LPCE-3_ CCD Spectroradiometer Integrating Sphere Compact System

LSG-6000 LM-79 Moving Detector Goniophotometer (Mirror Type C) fully meets the requirements of LM-79-19, EN13032-1 Clause 6.1.1.3 Spectrophotometer Type 4 Requirements, CIE S025, SASO2902, IS16106 and GB on optical parameter testing. LSG-6000 should be the latest upgrade of the LM-79-19 standard requirements, can automatically test the light intensity distribution curve of the 3D system, the test distance requirements range from 5 to 30 meters, can meet the test requirements of various light sources, such as LED light sources, plant lighting, HID light sources, indoor and outdoor lighting, street lights and floodlights and other lighting fixtures. Measurement parameters: Luminous intensity, Luminous intensity distribution, Regional luminous flux, Luminous efficiency, Luminance distribution, Utilization coefficient, Brightness limit curve, Glare grade, Maximum allowable distance height ratio, Isoinum illuminance graph, Up-emitting luminous flux, Down-emitting luminous flux, Isoless Illuminance Curve, Isoluminous Intensity Curve, Effective Luminous Angle, EEI, UGR, etc.

LM-79 Moving Detector Goniophotometer (Mirror Type C)

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