Clarification on Time-of-Flight Cover Glass

[J1234]

Hi, 

 

I was reading @John E KVAM excellent post on Time of flight sensor glass:

https://community.st.com/t5/mems-and-sensors/time-of-flight-cover-glass/ta-p/49259

and this documentation

https://www.st.com/content/ccc/resource/technical/document/application_note/group0/9d/93/be/33/13/be/46/19/DM00326504/files/DM00326504.pdf/jcr:content/translations/en.DM00326504.pdf

 

And was just wondering, how important is the IR coating:

Our application will have a large sheet of glass, shared by a display (see image for reference)

 

And it would be cost prohibitive to IR coat the whole glass. For reference the glass will be ~ 1.1 mm thick. 

Is this likely to cause problems?

[John E KVAM]

The illustration above was trying to indicate that if you had an IR coating, put it on the underside of the glass. 

IR coatings are not a must. Lots of people don't use them. If you are generally using the device inside, you won't have an issue. 

All those parameters discussed are additive. You can get away with some parameters being sub-optimal if the other parameters are pretty good. If the transmissivity of your glass is good, and you glass is 1.1mm thick, you should be OK. But watch the air gap. If it's large, you MUST use the gasket. 

 

- john