Luminous flux and efficiency



This integrating sphere with 50 cm diameter was designed in the light & lighting laboratory and custom made by Gigahertz Optik (Germany) in 2007. Apart from three sphere ports, this sphere has a perfect homogenous and diffuse reflecting white coating on the sphere wall. The ports are (from left to right in the figure) the calibration port, a detector port, and the measurement port. A separate calibration and measurement port was chosen to avoid substitution errors. Calibration and measurement are performed immediately one after another, without changing the sphere configuration (as opposed to classic integrating spheres).

The following options are available for the sphere:

  • A fiber with a lambertian diffusor positioned in the detection port aligned with the sphere wall.
  • A diaphragm with calibrated diameter which can be mounted on the calibration port.
  • An extra diffusor for larger detectors (to be mounted in the detection port).
  • Aluminum mounting plates for the light sources (which can be perfectly aligned with the sphere wall).
  • Lambertian diffusing material which can be custom sized to coat the aluminum plates.
  • A Peltier cooler to drive LEDs at different currents and different temperatures.


To perform practical measurements with this integrating sphere setup, the following items are available:

  • A power supply for the calibration standards
  • Different power supplies for the light sources (DC, PWM, mains voltage)
  • A power meter with 4 wire measurement configuration
  • A spectrometer with CCD
  • A power supply for the Peltier cooler
  • A computer with software for data processing
Calibration sources
Overview of the different ports (left to right: calibration, dection, sample port)
Overview of the different ports
Port configuration
Mounting plate with Peltier cooler
Optical fiber with diffusor