Measuring Head

The measuring head is robust. The Ethernet interface and the data lines to the computer are ready for connection. In the camera head, the control electronics, the FPGA as well as the readout electronics are installed, the optical bench and the OCT sensor. The sensor chip consists of 300 * 300 imaging elements. Each sensor has its own optics and its own signal preprocessing.

The image rate of the sensor is 1 Mio. fps, (1 Million frames per second) and the modulation frequency of the light front and demodulation is 5 kHz. The pulse source and the optical bench is installed in the interferometer. The test distance ranges between few millimeters and some centimeters. The single measuring head belongs to the most state-of-the-art OCT – equipment and enables professional working.

Measurement Process

A plane, monochrome light front is emitted by the light source. The light front is directed to the reference arm at the beam splitter and applied to the object (measuring arm). The light reflected and scattered at the measuring object reaches back to the sensor via the beam splitter after the light front on the beam splitter interferes with the light reflected by the reference arm.

The sensor receives interfering light fronts due the conditions of the measuring object and of its depth profiles. Differences in surface geometry, material, scattering or reflection are measured by the detector at a very high rate. The measuring head has dimensions of 70 mm * 55 mm * 200 mm and weighs  500 grams and includes:

  • the optics (adaptable to the measuring task)
  • the light source for generating the light front
  • the APS array (active sensor pixel array) with 300 * 300 pixels
  • the spectrometer
  • the signal preprocessing

The contact-free OCT method is used for:

  • measuring layer thickness
  • determination of refractive index
  • determination of roughness grade
  • determination of geometrical shapes
  • and much more