Why can't wireless charging be used through front glass? - chintan_io
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magicpat2010
Wireless charging can't be used through the front glass of a phone because it
needs to have a receiving (Rx) coil and not cause electrical interference with
the parts between the receiving and transmitting coils by the magnetic flux
produced by wireless charging.

If you look at the bottom of page 4 of this PDF document (numbered page 11 if
it were printed), [https://www.mouser.com/pdfDocs/TI-Designing-a-Qi-
compliant-r...](https://www.mouser.com/pdfDocs/TI-Designing-a-Qi-compliant-
receiver-coil.pdf), you can see a picture (Figure 8) that shows the
construction of wireless charging coils for phones. The Rx portion would be
inside the phone. Notice that there is a part titled "Rx Shield". The Rx
Shield is to protect components of the phone above it.

Figure 5 (on page 2 of the document) has a picture that shows the magnetic
flux density graphed. The fields produced are in the low mT range, so parts
need to be able to handle it without heating or interference and boards will
need to have appropriate filtering, if you wanted to charge through the front
glass.

