VL53L1X Low Range issue

[spiralbrain]

We use the VL53L1X in one of our products and have been doing that for over 2+ years now. As this device is not easily solderable, we have been relying on the Chinese supply of breakout boards used in the hobby market. 

Just recently we are facing range issues with entire lots of this sensor based boards. All of them exhibit range issues where the Sensor is unable to detect beyond 30 to 40cm. I thought it could be a calibration or offset issue. I've tried getting offset values using the 17% Gray sheets as recommended. Any help in this regard will be appreciated. Thanks.

[spiralbrain]

After having tried everything, I have put this on hold as we are way close to our delivery deadline. If this is the case I am sure many people will bring this up in the future, maybe a solution can be found then. For Now I have designed a custom board with the components and await its delivery. Thank you for all your help, If a solution is found, I will let everyone know.

[spiralbrain]

I removed the protective glass on one of the faulty sensors, The laser Cavity seems ok but the SPAD side has some resin in it, is it normal? Or it it flux that should not be there?  have we found the fault?

Photo attached.

[spiralbrain]

Bad Sensor

Good Sensor: 

This is not flux, the optical lens on the SPAD side seems to have transformed into an opaque solid. Like cataract, Its either age or excessive heat. The mystery has been solved.  Its amazing how this sensor seems to work up till half a meter even when in such a condition. Can I claim this as a warranty issue? :D

[John E KVAM · Accepted solution]

If you want to know what happened, you have to return the sensors. Find another bad on that you have not taken apart and start the return process. It's called return for RMA. (Return Merchandise Authorization)

But the process is not simple. You have to send the parts back through the chain that you bought them from. Generally, this is a distributor. Sometimes the company doing your assembly bought them from the distributor. It all goes back to ST the same way it came. 

That allows us to know who bought them, who soldered them, who stored them and for how long and a bunch of other bits of information that you are not aware of.

But looking at those pictures, there really is only one conclusion. Someone cooked them. They were cooked way too long at way too high a heat. 

The sensor's expected lifetime is so long, that your 'cataract' is not age related. It's heat. 

Start with your manufacturer, ask them for the refund. If they want to get that refund form their source, they have to provide all the information back up the chain. 

Because every one of these sensors has to be calibrated for laser safety, they were all checked at the factory. So returns that were not abused is almost non-existent. But if you really want to know what happened, this is how you go about it. 

- john