It feels a bit strange to report on a webcam privacy shade as if it were a novelty: various products already let users put a decorative background on screen in lieu of a live stream, or even pull a physical shade across the lens. What Apple is apparently proposing, though, is a camera with such privacy filters built into the camera module itself. The company just applied for a patent on a camera whose images could selectively transition from opaque to transparent and back again, depending on how much privacy is called for.
Based on that illustration up there, we're going to hazard a guess it could be used in Apple's MacBook and iMac lines, though the patent application doesn't explicitly exclude mobile devices, either. (In fact, the filing acknowledges a camera like this could be used in, ahem, a television.) What we'd really like to know is how easy it would be for the user to active the privacy mode. Alas, though, the USPTO doc doesn't give any definitive answers -- the filing suggests the user could choose to switch modes, or that launching certain applications (i.e., those that use the camera) might trigger a change in privacy settings. In any case, that's about all we can glean from the patent application, but feel free to peek for yourselves if you feel like letting your imaginations get ahead of you.