For the VL53L0X Emitter Exclusion Zone, what happens if the zone is breached?

[DScha.2]

I am adding a VL53L0X to an existing board design, and would like to keep the same footprint. A relatively small section of the emitter exclusion zone is breached ~16mm away from the top surface so I am curious what the effect would be and how significant? The 25 degree exclusion zone for the collector is clear of all obstructions.

[John E KVAM]

A lot depends on the obstruction. In the best case the transmitted photons would hit at an oblique angle and bounce harmlessly away. Or, if the obstruction were very black, the photons would be absorbed, and not interfere.

But if the obstruction were reflective, you would get additional crosstalk.

Crosstalk normally comes from light hitting the coverglass and bouncing back.

During the manufacturing process, there is a way to calibrate for it.

The photons from your obstruction will be the same as normal crosstalk and will add to it.

Best case, you will be able to calibrate it out.

If you are unable to calibrate it out, you might end up with ghost targets (that are not really there) or you will under-range to targets that exist.

Spend some extra time on the crosstalk calibration step, it might fix you right up.

But do try to shape the the obstruction so the light bounces away. That would be the best way out.

• john