GL Optic's new spectrometer and integrating sphere can be coupled for LED spectral test and measurement

Nov. 26, 2014

Optimal LED measurement in large-scale applications with GL Optic’s GL SPECTIS 6.0 and GL OPTI SPHERE 500

In the realm of LED measurement and testing, a lot of attention has as of late been given to the development of small, handy size devices, allowing for the quick and easy assessment of any light source. GL OPTIC has therefore been continually developing its range of hand-held state-of-the-art spectrometers. Yet the need for top performing spectrometers in industrial or extensive laboratory settings has by no means diminished. The growing number of quality requirements introduced by new standards for lighting has made it necessary to ensure constant control of LED products as they are being produced. It is in response to this particular need that GL OPTIC has developed a robust, laboratory-grade product engineered for large scale purposes: the GL SPECTIS 6.0.

It comes in a rack-mountable 2U 19” housing (480 x 262 x 88.9 mm) which can be easily integrated into a standard data cabinet and supports measurements in a wide spectral range of 200 nm to 1050 nm, spanning from ultraviolet (UV) through visible range (VIS) to near infrared (NIR), offering a high resolution of 3.5nm. The high-end spectrometer is specifically designed to meet the demands of production process control in the manufacture of LED chips or lamps and adheres to the requirements of ever more strict international lighting standards, such as CIE 127:2007 for LED measurements which defines techniques for assessing photometric and radiometric quantities such as total radiant flux or partial LED flux or IESNA LM-79-08 which describes procedures to perform reproducible measurements of total luminous flux, luminous intensity distribution or chromaticity of SSL products. The SPECTIS 6.0 also meets the ecodesign requirements for LEDs in accordance with EU Commission Regulation no. 1194/2012 which enforces minimum efficiency levels and labelling requirements of LED packaging. Another key characteristic of LED lighting is the issue of energy efficiency which is often compared to conventional light sources. This is typically characterized using luminous efficacy (measured in [lm/W]) and is determined by quantifying spectral characteristics of respective luminous elements assessed mainly on the basis of luminous flux and radiant power. These measurements can be made by coupling the spectrometer with an integrating sphere, such as the GL OPTI SPHERE 500. Spectrally calibrated and featuring a 500mm diameter, it is the ideal tool to measure radiant power and spectral distribution in medium-sized LED arrays. A variety of photometric parameters can be assessed simultaneously and include color coordinates, color temperature or the color rendering index (CRI). This in turn forms a basis to calculate the extent to which electronic components, drivers or power supplies influence the characteristics of the LEDs. The geometry of the GL OPTI SPHERE 500 allows for the installation of a variety of adapters to measure indivdual LEDs and all other types of light sources. To conform to CIE recommendations, front-emitting diodes can be measured at the wall of the sphere in 2π geometry, while other types are measured at the center of the sphere in 4π geometry. The port of the sphere features a precise 80mm aperture which can be used in partial flux measurements of LEDs. An auxiliary light source is also provided to compensate the self-absorption effect of the test LED. In addition, the walls of the sphere are coated with barium sulfate (BaSO4) which ensures high reflectance properties of up to 97%. As with all GL OPTIC integrating spheres, the OPTI SPHERE 500 with a spectral range spanning 240 nm to 2600 nm can be used with any GL OPTIC spectrometer, yet matching it with the high-end GL SPECTIS 6.0 will optimally meet the development and quality assurance needs of lamp manufacturers, as well scientific institutes, consultants, material researchers, and many other user groups.


GL OPTIC, the brand of JUST Normlicht GmbH - Mikolaj Przybyla, brand director


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