Instrument Systems – The expert for accurate light measurement

LED Test & Measurement – a proven track record

LEDs cannot be manufactured with consistent optical properties as a result of the production processes involved. Brightness and color can vary substantially from component to component even in the same production batch. This is why LEDs have to be tested during production and in their final application. Comprehensive optical characterization is also essential during research and development of LEDs and for LED-based products.

Instrument Systems has developed turnkey solutions for determining luminous intensity, luminous flux, color, spectrum and spatial radiation pattern of LEDs. The measurement systems generate very accurate results with reliable reproducibility in conformity with the guidelines of the CIE 127 document of the International Commission on Illumination. Instrument Systems uses high-performance spectroradiometers to deliver these solutions.

Two areas of application are defined for our LED measurement products:

  • Laboratory applications: In research and development and in quality control
  • Production testing: Wafer testing and die sorting in front-end, and testing and sorting of packaged LEDs in back-end

LED – the light of the future.

Since the development of high-brightness blue and white LEDs, the market for LED light has been booming. LEDs are used in displays, illuminated advertisements and lamps. The new light of white LEDs is already being integrated in cars, aircraft, traffic lights and classic architectural lighting. It’s no surprise that a brilliant future has been predicted for LEDs.

Companies like Osram, Philips and General Electric work round the clock to improve LED light. Instrument Systems is cooperating intensively with these companies on metrology. This commitment represents an investment in the future because joining forces in this way provides information on the needs of industry when it comes to measuring LEDs. We also make an important contribution to the definition of international standards. And this is one of the reasons why Instrument Systems is the market and technology leader in LED measurement today.

Solid-State Lighting – The light of the future with the right measurement equipment

LEDs have created a completely new product category in general lighting. As a new technology, SSL is the light of the future with exciting opportunities but also challenges.

Since the manufacturing process of LEDs requires extensive testing at the production stage and during quality assurance, SSL products have also placed more stringent demands on optical characterization. The electrical operating parameters and thermal management of a SSL lamp or luminaire exert a major influence on the light distribution and colorimetric properties.

Instrument Systems is the global market leader in LED test & measurement and has an extensive track record of experience in this innovative technology. We are therefore in a position to extend our expertise to the specific requirements of Solid-State Lighting with our new goniophotometers and integrating spheres.

We offer comprehensive turnkey solutions in combination with our refined range of spectroradiometers and photometers designed to identify the photometric and colorimetric characteristics of LED modules and all LED-based lamps and luminaires.

Display measurement – Discover our complete product range

Nowadays we encounter displays in every walk of life. All these applications require sophisticated measurement instrumentation in R&D and manufacturing.

Instrument Systems has a long track record as the market leader in test and measurement systems for displays in the automotive and avionics industry. And our comprehensive product range is used to test and calibrate smartphone displays, tablet PCs, and TV sets.

In 2012, Instrument Systems took over the DMS product line from Autronic-Melchers. These measurement systems allow the characteristics of LCD panels and OLEDs to be comprehensively analyzed.

Spectroradiometry and photometry – the entire light spectrum

Instrument Systems supplies technically refined test & measurement systems to meet all requirements in spectroradiometry and photometry, e.g. measurements of the solar spectrum, from a solar simulator or at an energy-saving lamp. These measurement systems are calibrated using standards that are based on PTB (Germany) or NIST (USA) reference standards.

Radiometric quantities describe the physical radiation properties over the entire spectrum from UV to infrared, while photometric quantities relate to the effect on the human eye and are therefore restricted to the visible range from 380 to 780 nm. Spectroradiometry relates to spectral measurements of radiometric quantities.

The following table gives an overview of the different optical quantities with sample applications:

Test & measurement accessories Radiometric unit Photometric unit
Energy-saving lamp ISP Integrating Sphere

Radiant power [W]

Luminous flux

LED LED Adapter

Radiant intensity

Luminous intensity
[lm/sr = cd]

Sun EOP External Optical Probe


[lm/m² = lux]

Display TOP Telescopic Optical Probe

[W/sr m²]


Spectoradiometry and photometry place extremely high requirements on the spectrometer, if accurate measurement results are to be attained. The high-quality and precise spectrometers from Instrument Systems have been specially designed for these applications. The appropriate measurement accessories are also supplied for the relevant radiometric and photometric quantities. Accessories are connected to the spectrometer by an innovative fiberoptic adapter. This feature maintains absolute calibration even if accessories are changed.

Miniature spectrometers with low-cost front-Illuminated CCD line sensors do not meet the specified requirements because their dynamic range and stability are not adequate for accurate absolute calibrations.


Instrument Systems recommends the following spectrometers for precise spectroradiometric measurements:

  • The CAS 140CT Array Spectrometer is ideal for taking measurements at flash lamps and solar simulators. Different models cover the spectral range from 200 to 2150 nm.
  • The Spectro 320 scanning spectrometer is supplied as a single or double monochromator and is ideal for applications that require a large dynamic range and very low stray light (e.g. UV-B measurements). This spectrometer also allows a broad spectral range from 190 to 5000 nm to be analyzed in a single scan.


Photometric measurements are restricted to the visible spectrum of 380 to 780 nm (360 to 830 nm in extended range). Photometric and colorimetric quantities can also be calculated from spectral data but the reverse calculation is not possible. Spectroradiometers rather than conventional photometers are therefore generally used to obtain accurate photometric measurements. Photometers also require a correction for the spectral mismatch.

The following spectrometers from Instrument Systems are recommended for photometric measurements:

  • The CAS 140CT Array Spectrometer as a precision measuring instrument to meet all requirements in R&D and production
  • The MAS 40 CCD Array Spectrometer as a low-cost entry-level instrument for laboratory settings and quality control