VL6180X measured distance is dependent on specularity of the target surface

[BLudi]

I am evaluating the VL6180X to be used in a microtiter plate detector device and have noticed the measured distance is significantly underestimated for specular/mirroring/glossy surfaces. Furthermore the results is stronglly dependent on the angle. If the surface is tilted along the long axis of the VL6180X, the measured distance increases both when its tilted to the right or to left. If the surface id tilted along the short axis of the VL6180X, the measured distance very stronly increases or decreases depending on the tilting direction. The effect is much larger than what could possibly be explained by simple geometry (and tilting matted surface has basically no effect).

What is the reason for these effects ? Can they be attenuated/eliminated or compensated for?

[John E KVAM · Accepted solution]

The Vertical Cavity Surface Emitting Laser (VCSEL) used has a limitation. The main bit of light that illuminates the center region of the cone starts just a touch ahead of the outer region. Generally this is not an issue, as the mathematical model used takes this into account. But for very reflective surfaces smooth the model breaks down a bit and there is a small offset. It is this effect you are seeing.

[BLudi]

Is this problem solved in the new VL53L3CX?