- O6D laser distance sensor
- Technology
O6D laser distance sensor: Time-of-flight technology
The O6D laser distance sensor reliably detects objects of varying color, texture, size, shape and material, in a wide range of environments and from mounting positions that prevent other optical sensors from working.
It overcomes common optical sensor challenges by reliably detecting objects without manual recalibration for different targets or changing environmental factors. The O6D achieves this using:
- Photonic mixer device (pmd) time-of-flight (ToF) technology requiring minimal light return
- A proprietary High Excess Gain feature to detect virtually any target
- Fast switching speed to automatically recalibrate when it detects an object
- Robust detection of small reflective, shiny or black objects
- Multicolored objects are reliably detected
- Reliable detection with environmental interferences
- Fast installation thanks to color and angle independence
- Measured distance information via IO-Link
Not all surfaces return the same amount of light:
- White surfaces reflect approximately 90% of incident light
- Gray reflects around 18%
- Black reflects just 6%
A sensor calibrated for one target type will underperform or fail entirely on another:
- Highly reflective surfaces such as polished metal or oiled steel flood the receiver with so much light that it saturates, producing no usable signal
- Black or matte targets return a signal too weak to cross the detection threshold
- Surface variations reduce reliability for triangulation-based sensors that calculate distance by measuring where reflected light lands on a receiver array. Geometric calculation breaks down when light scatters or gets redirected
- Steep mounting angles create the same effect: insufficient reflected light reaches the receiver at the required position, and detection fails
Two sensing engines dominate industrial optical distance measurement:
Complementary Metal-Oxide-Semiconductor (CMOS) and Time-of-Flight (ToF).
The O6D laser distance sensor from ifm uses pmd Time-of-Flight. It builds on phase-shift ToF with an additional, proprietary layer of sensing that standard ToF lacks.
The O6D laser sensor uses three features to reliably detect any object without manual recalibration:
pmd Time-of-Flight
Photonic mixer device (pmd) technology processes the returning phase-shifted light signal at the pixel level. Each pixel can independently measure phase shift. Because the measurement depends on phase shift rather than intensity, the O6D functions reliably across surface types and mounting angles that cause intensity-based sensors to fail.
This architecture gives the O6D two critical advantages:
- It requires only a small fraction of the reflected light to calculate distance accurately
- It is not dependent on the geometry of where that light lands on the receiver.
High Excess Gain feature
Fixed sensitivity settings prevent most optical sensors from detecting a wide range of colors or lighting conditions without recalibration. The O6D's patent-protected High Excess Gain feature produces a 10x increase in sensitivity for black target performance without sacrificing white target detection at close range.
The pmd receiver continuously monitors whether the incoming signal is saturated or insufficient changes its internal parameters to reflect what it captured. The process is similair to High Dynamics Range (HDR) in photography.
High Excess Gain eliminates the need for manual calibration or multiple sensor types as the two extremes are handled by the same sensor on the same line.
Switching Speed
The O6D sensor maintains full line-speed performance while continuously adapting to whatever target is in front of it. The adjustment process completes within its normal switching cadence of over 1 kHz.
Distribution center conveyor lines operate at fixed speeds with no margin for sensor lag. A meaningful drop in switching speed translates directly to missed detections as objects pass through the detection zone faster than the sensor can cycle.
The High Excess Gain adjustment cycle completes within 5 milliseconds, fast enough to not interrupt the output signal or reduce the sensor's switching cadence.
The O6D is a Class 1 laser device, operating at near-zero milliwatts of electrical power output. It does not require enclosures or operator precautions.
The sensing engine’s new pixel-based laser architecture is longer-lasting and more power-efficient than previous industrial laser types. Since it generates more internal heat than other pixel-based lasers, the O6D has a plastic housing, rather than metal, for heat dissipation.
The sensor’s streamlined visual display consists of dual status LEDs and two-button “teach” functionality. Since the O6D automatically recalibrates, controls are only needed to turn the sensor on and off and alert it to an initial target.
The O6D can use IO-Link to provide measured distance data digitally to the PLC alongside the standard switched output.