Based on LM-79 standard how to use integrating sphere and goniophotometer to test LED lamps

The permitted electro-optical test method for IESNA solid-state lighting products, specifically LM-79, is jointly developed by IESN and the ANSI Solid-State Lighting Committee, and the main contents include：：

1. Covering lamps including light sources and light sources used as lamps (such as LED renewal products)

2. The optical test method adopts the relative measurement method of integrating sphere, the absolute measurement method of goniophotometer and the spectroradiometric measurement method
The main function of the integrating sphere in the light source test process is to use it as a light collector, which is an important component of the photometric system. The integrating sphere is a hollow sphere. Reflective paint. According to the different photometric measuring equipment, the integrating sphere measuring system is divided into two types: integrating sphere photometer measuring system and integrating sphere spectral analysis system. The former uses a photometric probe as a detector and cooperates with a photometer to measure optical parameters; The latter uses an optical fiber to collect light from the spherical wall, and cooperates with a spectrometer to measure parameters such as luminosity, chromaticity, and radiance.

The distribution photometer is the main measurement equipment for the light distribution performance test of lamps. It can be used to measure the spatial light intensity of lamps or light sources, the total distribution of luminous flux and the efficiency of lamps and other parameters. The meter system consists of: precision turntable and control system, spectrum analysis system , standard lamp, alignment system, computer processing system and other parts.
Distribution of parameters such as total luminous flux and lamp efficiency. The meter system consists of: precision turntable and control system, spectrum analysis system, standard lamp, alignment system, computer processing system and other parts.

3. Optical information tests include: total luminous flux (lumens), luminous brightness (canteral) (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 integrating sphere plus photometer or spectroradiometer test:
This is the relative measurement method of the total luminous flux; the principle of measuring the total luminous flux by the integral method is to calibrate 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 tested LED lamp product is calculated by comparing it with the standard lamp Generally speaking, the integral method is suitable for testing the total luminous flux and chromaticity parameters of small integrated LED lamps and relatively small LED light sources. Advantages, usually the smaller the volume, the more accurate the test results of the lamps that are closer to the point light source.

The other is the photometric method using a goniophotometer:
This is the absolute measurement method of the total luminous flux. Using the photometric method to test the total luminous flux is to use a distributed photometer, which has few limitations in the total luminous flux test. A device that measures the light intensity of the light source or the illuminance of the light source at a given distance in the direction of the light source, and calculates the total luminous flux through the light intensity data in each direction.

The measurement principle, environment and test method of integrating sphere and distributed photometer are different, and the measurement results of the two are not comparable. We can choose the appropriate method to test according to different standards and different requirements.

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

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

As above, for the content of the LM-79 standard, Hangzhou Hongpu Light and Color has launched several products:

LED spectrometer integrating sphere integrated system, professionally used for measuring the photometric parameters, chromaticity parameters and electrical parameters of single LED and LED lamps. The measured data conforms to CIE177, CIE-13.3, CIE-84, ANSI-C78.377, (EU) 2019/2015 , GB/T24824, IESNA-LM-63-2, Optical-Engineering-49-3-033602, Measurement requirements in LM-80 and LM-79.

Compact Spectroradiometer Integrating Sphere System
Products that meet the requirements of the LM-79-19 standard, a 3D system that can automatically test the light intensity distribution curve, the test distance is 5 to 30 meters, and can meet the test requirements of various light sources, such as LED light sources, plant lighting, HID Various lighting fixtures such as light source, indoor and outdoor lighting, street light and flood light. Measurement parameters: light intensity, light intensity distribution, area luminous flux, luminous efficiency, brightness distribution, utilization factor, brightness limit curve, glare level, maximum allowable distance Ratio, iso-illuminance map, upper luminous flux, downward luminous flux, iso-illuminance curve, iso-intensity curve, effective luminous angle, EEI, UGR, etc.

Hangzhou Hopoo Light&Color Technology Co., Ltd. focuses on the production, research and development and sales of lighting and electrical testing instruments. The whole series of products are developed and produced in strict accordance with the requirements of ISO9001:2015; all products meet the requirements of CIE; in addition, All products of hopoocolor have passed CE certification and obtained the qualification to export to the European Union. The main products include goniophotometer, integrating sphere, spectroradiometer, illuminometer, colorimeter, and LED test instruments. 

If you want to know more technical or product information, please feel free to contact us.
Sales Department: 86 18069445092, Sales_fob@hopoocolor.com