Short range distance measurement to a point

[esilver]

I'm designing a custom LiDAR sensor for a project and I need a sensor to accurately measure the distance to a small point. I'm looking for an accuracy of +-5mm but the small the better, the maximum range it needs to measure is about 400mm and the minimum range is about 50mm. I would also like a ranging frequency of about 100Hz but that's not set in stone. I've been looking at the VL53 ToF sensors but they all have larger FoV's than I'd like so I have 2 questions:

Which ToF sensor would be best for these specifications?

Is there a way to reduce the FoV? (e.g. with a small aperture or a lens perhaps)

Any help would be appreciated and I'm happy to answer any questions.

[John E KVAM]

You have a lot of things working against you. 

the more time you give the sensor the better the accuracy. It can do 100hz, but the accuracy suffers a bit. 

One could focus the laser to a point, but you would be creating an invisible laser that could really damage your eyes. 

DON'T FOCUS THE LASER. it would be very dangerous.

So that leaves putting a 'blinder' on the input side to narrow the field of view. You could do this physically, but the VL53L1CB has a lens on the receive side and you can limit the Region of Interest to about 5 degrees square. 

That's probably your best bet. (The VL53L1X does too, but the CB version is faster in continuous mode and you wanted speed. 

So, let's try it. For $56 dollars, buy the P-Nucleo-53L1A2. With a USB (mini connector) plug it into your PC, download the free software and run it. See if you can get it to work the way you want. If it works, great. If not, you are only out $56 dollars and an hour or two. 

 But if you really want a point, I'm afraid you are out of luck. We really cannot do that.

- john