TOP 200 - telescopic optical probe for radiance and luminance measurements

The TOP 200 telescopic optical probe is typically used for the testing of displays and panel graphics. It has been completely redesigned and is now based on Pritchard style optics with an integrated alignment camera. In comparison to the previous model (TOP 100), all functions are now controlled via software, so that manual operation is no longer required except for focus adjustment.  

TOP 200 telescopic optical probe

Light is guided from the TOP 200 to the spectrometer via a multimode fiber. A patented mode mixer from Instrument Systems ensures consistent transmission through the fiber. This feature guarantees reproducible measurement results, even when the fiber is physically disturbed somewhere along its length.

Use of a Pritchard style optic means that the viewing area around the spot can be observed and monitored during the measurement. The image generated by the alignment camera is automatically imported by the SpecWin Pro software and saved together with the measurement results.


  • Pritchard optics with an aperture mirror inclined at only 15° delivers perfectly round and sharp image spots (products from other manufacturers can exhibit ellipticity and blur)
  • flexible connection via optical fibers incorporating a patented mode mixer ensures reproducible results and very low polarization sensitivity
  • 4 different measurement spot sizes selectable via software
  • internal alignment camera with a wide field of view
  • smallest measurement spot 80 µm
  • optional illumination of the test object  

Ordering Information:

Item Nr.Item Description
Basic unit and fiber
TOP200-100basic telescope unit with adapter for multimode fiber (w/o. lens and fiber)
TOP200-101multimode fiber (diameter 1 mm) with mode mixer and PLG connector; 300-2200 nm
TOP200-102UV multimode fiber (diameter 1 mm) with mode mixer and PLG connector; 190-1350 nm
Objective lenses and close-up lenses
TOP100-308 fixed focal length 28 mm; F/2.8; 370-1100 nm
TOP100-310zoom 70-300 mm; F/4.2-5.8; 370-1100 nm
TOP100-311fixed focal length 60 mm; F/2.8; 370-1100 nm
TOP100-312fixed focal length 100 mm;F/2.8; 370-1100 nm
TOP100-313fixed focal length 200 mm; F/4.0; 370-1100 nm
TOP100-316zoom 200-500 mm; F/5.0-6.3; 370-1100 nm
TOP100-319fixed focus 90 mm (HRL90); high resolution; 370-1100 nm
TOP100-322UV lens 105 mm; F/4.0; 200-800 nm
TOP100-350close-up lens; x4; 370-1100nm
TOP100-351close-up lens; x2; 370-1100nm
TOP100-360UV close-up lens; x4; 200-800 nm
TOP100-361UV close-up lens; x2; 200-800 nm

The following table provides an overview of the spot sizes available with the 2 most important lenses:

TOP100-311, 60 mm focal lengthHRL90
Working Distance 180 mm 500 mm1 m230mm
Aperture *)Spot size [mm]
Camera field of view [mm]
Height 4.425592.2

*) Only apertures 1 to 4 can be used with the standard multimode fiber.

Pritchard optics

The main component is a mirrored disc, positioned at a particular inclination in the imaging plane of the lens. The disc contains several elliptical holes, representing the separate apertures which define the size of the measurement spot. When viewed along the optical axis, the ellipses are designed to appear circular. The input facet of the fiber is placed immediately behind the aperture disc. Light reflected from the mirrored surface of this disc is reflected by a second mirror onto an alignment camera. The software selectable aperture appears as a central black spot in the image on the camera. As this point defines the aperture as well as the spot on the test object, an exact positioning of the test object is assured.