Instrument Systems has developed a range of suitable measurement adapters for measuring luminous intensity [cd] of LEDs. Differentiated is determined by their useable spectral range (visible or UV), the required measurement geometry ILED-A or ILED-B and the intended application (laboratory or manufacturing).

Incorporating a diffuser with a precision aperture of 1 cm² these Measurement adapters represent the light sensitive area of the detector. An entrance facet of a fiber bundle is positioned behind the diffuser and serves to couple the light into the spectrometer. This specific design is characterized by a high light throughput together with acceptable homogeneity of the detector area. LED-4xx series of measurement adapters is particularly suitable for low light output LEDs as well as for fast production testing.

If you require require the highest accuracy, the LED 25 was developed for “Averaged LED Intensity” measurements according to CIE 127 recommendations. It is based on an integrating sphere and features a perfectly homogeneous light sensitivity over the entire detector area, although with significant sacrifice of the light throughput.

LED-4xx measurement adapters prove compatible with all test sockets of the LED-5xx, -6xx, and -81x series. A clamping fixture. of reproducible and exact positioning of the LEDs is ensured by use of Special shortened versions that are available for use in manufacturing environments (e.g. in combination with LED sorting machines.


  • CIE 127 compliant for luminous intensity or “Averaged LED Intensity”
  • available in configurations for ILED-A and ILED-B
  • high light throughput enables short acquisition times
  • clamping fixture ensures reproducible positioning of LED test sockets
  • suitable for all LED test sockets with 25 mm diameter (LED-5xx, LED-6xx, LED-81x)
  • connects via fiber bundle to all Instrument Systems spectrometers


ModelSpectral rangeMeasurement geometryFormat
Measurement adapter for lab applications (with LED test sockets)
LED25-430UV-VIS-IRCIE ILED-Bintegrating sphere
LED25-440UV-VIS-IRCIE ILED-Aintegrating sphere
Short measurement adapter for production applications
LED-433-1 1)VIS-IRCIE ILED-Bdiffuser
LED-434-1 1)UV-VIS-NIRCIE ILED-Bdiffuser
LED-453VIS-IR0.01 sr at 50 mm separationdiffuser
LED-454UV-VIS-NIR0.01 sr at 50 mm separationdiffuser
LED-439 2) 
LED25-235 3) CIE ILED-Bintegrating sphere
1) Version with protective glass
2) LED-439 is an extension for use of the LED-43x und LED-45x adapters with the Instrument Systems LED test sockets
3) Adapter for LED 25 optical probe

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