Infrared Position Detector for OEM Integration

Thermal PSD

Position Sensitive Device

greenTEG’s Infrared Position Detector is a Thermal PSD (Position Sensitive Device). The Thermal PSD consists of a Thermopile Laser Power Sensor, in which the thermocouples are electrically connected in four separate sections. (see schematic drawing below). The sensors are packaged to ensure the thermal coupling of all four quadrants and coated with a black absorber. An incoming laser beam introduces a lateral heat flow in the Thermal PSD, which causes a position dependent voltage signal in each of the four quadrants. The latter allows you to determine exactly where the laser beam is positioned.

This Wikipedia article gives a good explanation of the PSD concept: PSD on Wikipedia

Advantages of Thermal PSD’s

As Thermal PSDs consist of a thermopile laser detectors, they offer the same advantages as thermopile detectors.

  • Flat Spectral Sensitivity from 190 nm to 15 µm
  • Sensitivity Independence toward Angle of Incoming Radiation
  • Measureable Laser Powers of 1 mW to 5 Watts (extendable to 25 W)

Thermal PSD Principle

How to use a Thermal PSD

Thermal PSDs work very similarly to conventional PSDs. The only difference in usage is that a Thermal PSD generates voltage signals, instead of a current signal. As these voltage signals are typically in the mV range, voltage signal amplification is needed prior to data interpretation.

Thermal PSD Quadrant Response

Applications for Thermal PSD’s

Thermal PSD’s can be used for a number of positioning applications. The most common applications are

  • Position control mechanisms, especially within IR laser systems
  • Measurement and control of thermal and mechanical distortions
  • Centering of laser beams

Thermal PSD’s

The IR Thermal PSD’s are coming soon. If you wish to receive the preliminary datasheet or be informed when these Detectors are released, send us an email.

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