Optical Triangulation Position Sensors

Optical triangulation position sensors use reflected waves to pinpoint position and displacement. The source of these waves may be a light emitting diode (LED), infrared (IR) light, or laser. Most optical triangulation position sensors house the sensor itself with the emitter. The sensor detects the beam that is reflected from the surface or object and provides an output that varies with the distance. Outputs for optical triangulation position sensors include analog current, analog voltage, and frequency. Digital, serial, and parallel outputs are also available, along with alarms and changes in state of switches.  

Typically, the sensing component for optical triangulation position sensors is either a charged coupled device (CCD) or a photodiode (PSD). The sampling rate is important, as this specification may determine the suitability of optical triangulation position sensors for specific applications. Beam patterns are designated as point, line, or area. To achieve a line pattern, many point-style sensors are used together in a line. To create an area scan, several optical triangulation position sensors are used together in a matrix or other shape. 

Optical triangulation position sensors have a working range and a reference or standoff distance. This standoff distance is the mid-point in the working range. By definition, the working range is either more or less the reference-distance and usually given as a value. For example, a sensor with a reference of 9” and a working range of 4” will have an effective total range of 8” over which it can measure. Since the midpoint of that range is 9” from the sensor, the distance to measure must be between 5” and 13” from the sensor.  

Optical triangulation position sensors may use either visible or invisible light beams. Sometimes, a visible beam can make the sensors easy to mount and aim at a target. Occasionally, a visible beam can be undesirable. For instance, in a factory or processing center personnel are working, a visible beam may be distracting and potentially lead to accidents. Additional considerations when selecting optical triangulation position sensors are resolution and accuracy. Resolution is the smallest unit of distinction that optical triangulation position sensors can detect. Accuracy is a percentage of full scale.

• Position Sensors and Position-Sensing Instruments
  Position sensors include wide range of sensors, switches and technologies that are used to determine the placement, speed or movement, direction, and location of a given target. Linear position...
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• Optical Triangulation Sensors
  Optical triangulation sensors use reflected waves, whose source may be a LED, infrared, or laser source to pinpoint position and displacement. A sensor, usually integrally housed with the emitter,...
  (read more)

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