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Laser distance sensor with time-of-flight technology for precise measurement

Most important features at a glance:

  • Reliable photoelectric distance detection with long range
  • Very good reflection resistance and background suppression for reliable switching
  • High precision for the detection of small parts
  • Colour-independent measurement even with difficult surfaces
  • Versions with laser protection class 1 or 2

Function principle

The sensor uses laser to transmit a modulated light wave which is reflected back by the object to be measured. The phase position of the received reflected light signal is compared with the phase position of the transmitted light. Based on the phase shift, i.e. the "distance" between the wave crests, the time of flight of the light is determined and the distance between the sensor and the object is calculated.

Precision within a millimetre

The PMD sensors from ifm use a "system-on-chip" design: Both sensor element and electronics for signal evaluation are integrated on a single silicon chip called a Photonic Mixer Device (PMD).  Advantage: This innovative ifm design offers high measurement accuracy in a compact, industrially compatible housing – at a fraction of the price of conventional systems. 

With the extremely small laser light spot, the sensors are perfectly suited for the detection of small parts, e.g. in error-proofing applications.

Detection of difficult surfaces made easy

What is particularly special about the PMD technology: The PMD sensors measure the distance irrespective of the surface colour. Even ambient light sources, reflective, oil film wetted surfaces or very dark objects are no problem. The impact angle of the object may be up to 20 degrees.

PMD sensors detect objects with laser protection class 1 which is uncritical to the eye. The excellent reflection resistance and background suppression, together with a high excess gain, enable reliable operation. The switch point is set easily and within a millimetre by means of user-friendly 3-button handling or alternatively via IO-Link. It also allows provision of the current distance value.