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Sometimes PCB designers will draw some art on unused PCB areas. Like here and here.

Looks great, but does this affect schema functioning? According to answers to this question an entirely isolated stripe of aluminum foil may act as a stripe antenna.

So I'd imagine the following scenario is quite possible:

  1. a PCB layout is designed and some area is left unused
  2. an artwork is added there
  3. the artwork adds capacitance or otherwise affects operations

Does PCB artwork affect schema operation? How do designers validate the effects are tolerable?

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Most artwork - with the exception of homemade boards - is done on the silkscreen layer, not in the copper layer, so should have no electrical effect. Artwork on the copper layer could increase parasitic capacitance in neighbouring traces.

Since it's rare for modern professionally produced boards to not have a separate silkscreen layer, I suspect the only people doing artwork in the copper layer are people producing their own boards - and they'll validate that it's not a problem simply by empirical testing.

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I have done artwork, professionally, in the copper layers. Often it is easier to "slip the artwork past the bosses" if it is done in copper, since does not stand out as much as white silkscreen on green boards.

Sometimes I would do the artwork in "negative" on the power planes. To view the art you would have to hold the PCB up against the light, and allow the light to shine through the PCB.

In theory, any extra (or removed) copper could effect how the circuit operates. But when when I did this I was careful to put the art in areas of the PCB that were basically unused and any side effects were minimal to non-existent.

It would be silly to add artwork that negatively effected circuit operation.

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The 1st Mickey Mouse watch had the cartoon character etched in metal on the silicon chip. We saw with our SEM back in the early 80's. Designer Logos are common often hidden from obvious viewers. Fab shops often add their own to the silkscreen. If a logo was added, I would suspect the project designer would have been shown it and approved it. I did not see any interference in the examples I've seen.

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  • \$\begingroup\$ The three or four PCB shops that I use typically add logos and date/batch codes in copper, not silkscreen. But I have seen other shops do silkscreen. The pcb designer is never asked to approve it (unless they specifically request this in advance). I too have not seen interference from this. \$\endgroup\$
    – user3624
    Dec 6 '12 at 14:05
  • \$\begingroup\$ Most shops with experience I used, prefer to use copper as the features are finer but may choose screen print if there is not room or doubt. But out of 7 companies, I have worked for, never seen a "Designer" not review artwork before it is complete and is responsible for the design implementation as a whole. But I agree board shop rarely asks for permission unless specified for Logo placement. If PCB design is farmed out, it is always sent back for review. The same is true for UL logo for safety. \$\endgroup\$ Dec 6 '12 at 18:21

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